U.S. patent application number 13/850805 was filed with the patent office on 2013-08-22 for surgical implantation method and devices for an extra-articular mechanical energy.
This patent application is currently assigned to Moximed, Inc.. The applicant listed for this patent is Moximed, Inc.. Invention is credited to Anton G. Clifford, Michael E. Landry, Mary O'Connell, Paul Tornetta, III.
Application Number | 20130218272 13/850805 |
Document ID | / |
Family ID | 48982856 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130218272 |
Kind Code |
A1 |
Clifford; Anton G. ; et
al. |
August 22, 2013 |
Surgical Implantation Method and Devices for an Extra-Articular
Mechanical Energy
Abstract
A surgical implantation approach for preparing a patient and
precisely and effectively placing an energy absorbing apparatus
relative to the patient's anatomy. Various surgical implantation
apparatus and methods for achieving proper device-to-anatomy
juxtapositional relationships are employed in the implantation
approach.
Inventors: |
Clifford; Anton G.;
(Mountain View, CA) ; O'Connell; Mary; (Menlo
Park, CA) ; Landry; Michael E.; (Austin, TX) ;
Tornetta, III; Paul; (Chesnut Hill, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Moximed, Inc.; |
|
|
US |
|
|
Assignee: |
Moximed, Inc.
Hayward
CA
|
Family ID: |
48982856 |
Appl. No.: |
13/850805 |
Filed: |
March 26, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12113162 |
Apr 30, 2008 |
8425616 |
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13850805 |
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Current U.S.
Class: |
623/13.12 |
Current CPC
Class: |
A61B 17/1739 20130101;
A61B 17/68 20130101; A61N 1/36071 20130101; A61B 17/88 20130101;
A61B 17/6425 20130101; A61B 2017/567 20130101; A61F 2/3836
20130101; A61B 17/1728 20130101; A61B 17/1764 20130101; A61F 2/08
20130101; A61B 2090/061 20160201 |
Class at
Publication: |
623/13.12 |
International
Class: |
A61F 2/08 20060101
A61F002/08 |
Claims
1-11. (canceled)
12. A method of attaching a medical device across a joint including
first and second members, comprising: attaching a first base to the
first member with compression and locking screws; attaching a
second base to the second member with one or more of compression
and locking screws; and affixing a third component to the first and
second bases.
13. A method of implanting a medical device with an articulating
element across an articulating knee joint, comprising: viewing a
femur and a tibia of the articulating joint from a side vantage
point; identifying a midpoint of Blumensaat's line; configuring the
medical device such that the articulating element thereof
corresponds to the midpoint of Blumensaat's line.
14. The method of claim 12, further comprising placing an elongate
member in first member and passing a guide over the elongate member
to select the first base prior to attaching the first base to the
first member.
15. The method of claim 14, wherein the first member is the femur
and the second member is the tibia.
16. The method of claim 15, wherein the third component includes a
compression spring for reducing the load on the joint.
17. The method of claim 12, wherein the third component is affixed
to the first and second bases by two pivotal connections.
18. The method of claim 17, wherein the pivotal connections are
ball and socket connections.
19. The method of claim 13, wherein the articulating element is
positioned anterior and proximal to a midpoint of Blumensaat's
line.
20. The method of claim 13, wherein the medical device comprises a
first base affixed to the femur, a second base affixed to the
tibia, and an articulating load absorbing component connected
between the first and second bases.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 11/775,139, filed Jul. 9, 2007, a
continuation-in-part of U.S. application Ser. No. 11/775,149, filed
Jul. 9, 2007 and a continuation-in-part of U.S. application Ser.
No. 11/775,145, filed Jul. 9, 2007, the entire disclosures of which
are expressly incorporated herein by reference..
BACKGROUND
[0002] The present disclosure is directed towards methods for
treating tissue of a body and more particularly, towards procedures
and devices for implanting an extra-articular mechanical energy
absorbing apparatus.
[0003] Both humans and other mammals belong to the subphylum known
as vertebrata. The defining characteristic of a vertebrate is
considered the backbone or spinal cord, a brain case, and an
internal skeleton. In biology, the skeleton or skeletal system is
the biological system providing physical support in living
organisms. Skeletal systems are commonly divided into three
types--external (an exoskeleton), internal (an endoskeleton), and
fluid based (a hydrostatic skeleton).
[0004] An internal skeletal system consists of rigid (or
semi-rigid) structures, within the body, moved by the muscular
system. If the structures are mineralized or ossified, as they are
in humans and other mammals, they are referred to as bones.
Cartilage is another common component of skeletal systems,
supporting and supplementing the skeleton. The human ear and nose
are shaped by cartilage. Some organisms have a skeleton consisting
entirely of cartilage and without any calcified bones at all, for
example sharks. The bones or other rigid structures are connected
by ligaments and connected to the muscular system via tendons.
[0005] A joint is the location at which two or more bones make
contact. They are constructed to allow movement and provide
mechanical support, and are classified structurally and
functionally. Structural classification is determined by how the
bones connected to each other, while functional classification is
determined by the degree of movement between the articulating
bones. In practice, there is significant overlap between the two
types of classifications.
[0006] There are three structural classifications of joints, namely
fibrous or immovable joints, cartilaginous joints and synovial
joints. Fibrous/Immovable bones are connected by dense connective
tissue, consisting mainly of collagen. The fibrous joints are
further divided into three types: [0007] sutures which are found
between bones of the skull; [0008] syndesmosis which are found
between long bones of the body; and [0009] gomphosis which is a
joint between the root of a tooth and the sockets in the maxilla or
mandible.
[0010] Cartilaginous bones are connected entirely by cartilage
(also known as "synchondroses"). Cartilaginous joints allow more
movement between bones than a fibrous joint but less than the
highly mobile synovial joint. Synovial joints have a space between
the articulating bones for synovial fluid. This classification
contains joints that are the most mobile of the three, and includes
the knee and shoulder. These are further classified into ball and
socket joints, condyloid joints, saddle joints, hinge joints,
center of rotation joints, and gliding joints.
[0011] Joints can also be classified functionally, by the degree of
mobility they allow. Synarthrosis joints permit little or no
mobility. They can be categorized by how the two bones are joined
together. That is, synchrondoses are joints where the two bones are
connected by a piece of cartilage. Synostoses are where two bones
that are initially separated eventually fuse together as a child
approaches adulthood. By contrast, amphiarthrosis joints permit
slight mobility. The two bone surfaces at the joint are both
covered in hyaline cartilage and joined by strands of
fibrocartilage. Most amphiarthrosis joints are cartilaginous.
[0012] Finally, diarthrosis joints permit a variety of movements
(e.g. flexion, adduction, pronation). Only synovial joints are
diarthrodial and they can be divided into six classes: 1. ball and
socket--such as the shoulder or the hip and femur; 2. hinge--such
as the elbow; 3. center of rotation--such as the radius and ulna;
4. condyloidal (or ellipsoidal)--such as the wrist between radius
and carps, or knee; 5. saddle--such as the joint between carpal
thumbs and metacarpals; and 6. gliding--such as between the
carpals.
[0013] Synovial joints (or diarthroses, or diarthroidal joints) are
the most common and most moveable type of joints in the body. As
with all other joints in the body, synovial joints achieve movement
at the point of contact of the articulating bones. Structural and
functional differences distinguish the synovial joints from the two
other types of joints in the body, with the main structural
difference being the existence of a cavity between the articulating
bones and the occupation of a fluid in that cavity which aids
movement. The whole of a diarthrosis is contained by a ligamentous
sac, the joint capsule or articular capsule. The surfaces of the
two bones at the joint are covered in cartilage. The thickness of
the cartilage varies with each joint, and sometimes may be of
uneven thickness. Articular cartilage is multi-layered. A thin
superficial layer provides a smooth surface for the two bones to
slide against each other. Of all the layers, it has the highest
concentration of collagen and the lowest concentration of
proteoglycans, making it very resistant to shear stresses. Deeper
than that is an intermediate layer, which is mechanically designed
to absorb shocks and distribute the load efficiently. The deepest
layer is highly calcified, and anchors the articular cartilage to
the bone. In joints where the two surfaces do not fit snugly
together, a meniscus or multiple folds of fibro-cartilage within
the joint correct the fit, ensuring stability and the optimal
distribution of load forces. The synovium is a membrane that covers
all the non-cartilaginous surfaces within the joint capsule. It
secretes synovial fluid into the joint, which nourishes and
lubricates the articular cartilage. The synovium is separated from
the capsule by a layer of cellular tissue that contains blood
vessels and nerves.
[0014] Cartilage is a type of dense connective tissue and as shown
above, it forms a critical part of the functionality of a body
joint. It is composed of collagenous fibers and/or elastin fibers,
and cells called chondrocytes, all of which are embedded in a firm
gel-like ground substance called the matrix. Articular cartilage is
avascular (contains no blood vessels) and nutrients are diffused
through the matrix. Cartilage serves several functions, including
providing a framework upon which bone deposition can begin and
supplying smooth surfaces for the movement of articulating bones.
Cartilage is found in many places in the body including the joints,
the rib cage, the ear, the nose, the bronchial tubes and between
intervertebral discs. There are three main types of cartilage:
hyaline, elastic and fibrocartilage.
[0015] Chondrocytes are the only cells found in cartilage. They
produce and maintain the cartilaginous matrix. Experimental
evidence indicates that cells are sensitive to their mechanical
(stress-strain) state, and react directly to mechanical stimuli.
The biosynthetic response of chondrocytes was found to be sensitive
to the frequency and amplitude of loading (Wong et al., 1999 and
Kurz et al., 2001). Recent experimental studies further indicate
that excessive, repetitive loading may induce cell death, and cause
morphological and cellular damage, as seen in degenerative joint
disease (Lucchinetti et al., 2002 and Sauerland et al., 2003).
Islam et al. (2002) found that continuous cyclic hydrostatic
pressure (5 MPa, 1 Hz for 4 hours) induced apoptosis in human
chondrocytes derived from osteoarthritic cartilage in vitro. In
contrast, cyclic, physiological-like loading was found to trigger a
partial recovery of morphological and ultra-structural aspects in
osteoarthritic human articular chondrocytes (Nerucci et al.,
1999).
[0016] Cancellous bone (also known as trabecular, or spongy) is a
type of osseous tissue which also forms an important aspect of a
body joint. Cancellous bone has a low density and strength but very
high surface area, that fills the inner cavity of long bones. The
external layer of cancellous bone contains red bone marrow where
the production of blood cellular components (known as
hematopoiesis) takes place. Cancellous bone is also where most of
the arteries and veins of bone organs are found. The second type of
osseous tissue is known as cortical bone, forming the hard outer
layer of bone organs.
[0017] Various maladies can affect the joints, one of which is
arthritis. Arthritis is a group of conditions where there is damage
caused to the joints of the body. Arthritis is the leading cause of
disability in people over the age of 65.
[0018] There are many forms of arthritis, each of which has a
different cause. Rheumatoid arthritis and psoriatic arthritis are
autoimmune diseases in which the body is attacking itself. Septic
arthritis is caused by joint infection. Gouty arthritis is caused
by deposition of uric acid crystals in the joint that results in
subsequent inflammation. The most common form of arthritis,
osteoarthritis is also known as degenerative joint disease and
occurs following trauma to the joint, following an infection of the
joint or simply as a result of aging.
[0019] Unfortunately, all arthritides feature pain. Patterns of
pain differ among the arthritides and the location. Rheumatoid
arthritis is generally worse in the morning; in the early stages,
patients often do not have symptoms following their morning
shower.
[0020] Osteoarthritis (OA, also known as degenerative arthritis or
degenerative joint disease, and sometimes referred to as
"arthrosis" or "osteoarthrosis" or in more colloquial terms "wear
and tear"), is a condition in which low-grade inflammation results
in pain in the joints, caused by wearing of the cartilage that
covers and acts as a cushion inside joints. As the bone surfaces
become less well protected by cartilage, the patient experiences
pain upon weight bearing, including walking and standing. Due to
decreased movement because of the pain, regional muscles may
atrophy, and ligaments may become more lax. OA is the most common
form of arthritis.
[0021] The main symptoms of osteoarthritis is chronic pain, causing
loss of mobility and often stiffness. "Pain" is generally described
as a sharp ache, or a burning sensation in the associated muscles
and tendons. OA can cause a crackling noise (called "crepitus")
when the affected joint is moved or touched, and patients may
experience muscle spasm and contractions in the tendons.
Occasionally, the joints may also be filled with fluid. Humid
weather increases the pain in many patients.
[0022] OA commonly affects the hand, feet, spine, and the large
weight-bearing joints, such as the hips and knees, although in
theory, any joint in the body can be affected. As OA progresses,
the affected joints appear larger, are stiff and painful, and
usually feel worse, the more they are used and loaded throughout
the day, thus distinguishing it from rheumatoid arthritis. With
progression in OA, cartilage looses its viscoelastic properties and
it's ability to absorb load.
[0023] Generally speaking, the process of clinical detectable
osteoarthritis is irreversible, and typical treatment consists of
medication or other interventions that can reduce the pain of OA
and thereby improve the function of the joint. According to an
article entitled Surgical approaches for osteoarthritis by
Klaus-Peter Gunther, MD, over recent decades, a variety of surgical
procedures have been developed with the aim of decreasing or
eliminating pain and improving function in patients with advanced
osteoarthritis (OA). The different approaches include preservation
or restoration of articular surfaces, total joint replacement with
artificial implants, and arthrodeses.
[0024] Arthrodeses are described as being reasonable alternatives
for treating OA of small hand and foot joints as well as
degenerative disorders of the spine, but were deemed to be rarely
indicated in large weight-bearing joints such as the knee due to
functional impairment of gait, cosmetic problems and further
side-effects. Total joint replacement was characterized as an
extremely effective treatment for severe joint disease. Moreover,
recently developed joint-preserving treatment modalities were
identified as having a potential to stimulate the formation of a
new articular surface in the future. However, it was concluded that
such techniques do not presently predictably restore a durable
articular surface to an osteoarthritic joint. Thus, the correction
of mechanical abnormalities by osteotomy and joint debridement are
still considered as treatment options in many patients. Moreover,
patients with limb malalignment, instability and intra-articular
causes of mechanical dysfunction can benefit from an osteotomy to
provide pain relief The goal being the transfer of weight-bearing
forces from arthritic portions to healthier locations of a
joint.
[0025] Joint replacement is one of the most common and successful
operations in modern orthopaedic surgery. It consists of replacing
painful, arthritic, worn or diseased parts of the joint with
artificial surfaces shaped in such a way as to allow joint
movement. Such procedures are a last resort treatment as they are
highly invasive and require substantial periods of recovery. Joint
replacement sometimes called total joint replacement indicating
that all joint surfaces are replaced. This contrasts with
hemiarthroplasty (half arthroplasty) in which only one bone's joint
surface is replaced and unincompartmental arthroplasty in which
both surfaces of the knee, for example, are replaced but only on
the inner or outer sides, not both. Thus, arthroplasty as a general
term, is an operative procedure of orthopaedic surgery performed,
in which the arthritic or dysfunctional joint surface is replaced
with something better or by remodeling or realigning the joint by
osteotomy or some other procedure. These procedures are also
characterized by relatively long recovery times and their highly
invasive procedures. The currently available therapies are not
condro-protective. Previously, a popular form of arthroplasty was
interpositional arthroplasty with interposition of some other
tissue like skin, muscle or tendon to keep inflammatory surfaces
apart or excisional arthroplasty in which the joint surface and
bone was removed leaving scar tissue to fill in the gap. Other
forms of arthroplasty include resection(al) arthroplasty,
resurfacing arthroplasty, mold arthroplasty, cup arthroplasty,
silicone replacement arthroplasty, etc. Osteotomy to restore or
modify joint congruity is also an arthroplasty.
[0026] Osteotomy is a related surgical procedure involving cutting
of bone to improve alignment. The goal of osteotomy is to relieve
pain by equalizing forces across the joint as well as increase the
lifespan of the joint. This procedure is often used in younger,
more active or heavier patients. High tibial osteotomy (HTO) is
associated with a decrease in pain and improved function. However,
HTO does not address ligamentous instability--only mechanical
alignment. HTO is associated with good early results, but results
deteriorate over time.
[0027] Other approaches to treating osteoarthritis involve an
analysis of loads which exist at a joint. Both cartilage and bone
are living tissues that respond and adapt to the loads they
experience. If a joint surface remains unloaded for appreciable
periods of time the cartilage tends to soften and weaken. Further,
as with most materials that experience structural loads,
particularly cyclic structural loads, both bone and cartilage begin
to show signs of failure at loads that are below their ultimate
strength. However, cartilage and bone have some ability to repair
themselves. There is also a level of load at which the skeleton
will fail catastrophically. Accordingly, it has been concluded that
the treatment of osteoarthritis and other conditions is severely
hampered when a surgeon is not able to precisely control and
prescribe the levels of joint load. Furthermore, bone healing
research has shown that some mechanical stimulation can enhance the
healing response and it is likely that the optimum regime for a
cartilage/bone graft or construct will involve different levels of
load over time, e.g. during a particular treatment schedule. Thus,
there has been identified a need for devices which facilitate the
control of load on a joint undergoing treatment or therapy, to
thereby enable use of the joint within a healthy loading zone.
[0028] Certain other approaches to treating osteoarthritis
contemplate external devices such as braces or fixators which
control the motion of the bones at a joint or apply cross-loads at
a joint to shift load from one side of the joint to the other.
Various of these approaches have had some success in alleviating
pain but suffer from patient compliance or lack an ability to
facilitate and support the natural motion and function of the
diseased joint. Notably, the motion of bones forming a joint can be
as distinctive as a finger print, and thus, each individual has his
or her own unique set of problems to address. Therefore, mechanical
approaches to treating osteoarthritis have had limited
applications.
[0029] Prior approaches to treating osteoarthritis have also been
remiss in acknowledging all of the basic functions of the various
structures of a joint in combination with its unique movement. That
is, in addition to addressing loads at a joint and joint movement,
there has not been an approach which also acknowledges the
dampening and energy absorption functions of the anatomy, and
taking a minimally invasive approach in implementing solutions.
Prior devices designed to reduce the load transferred by the
natural joint typically describe rigid body systems that are
incompressible. Mechanical energy is the product of force (F) and
displacement distance (s) of a given mass (i.e., E=Fxs, for a given
mass M). These systems have zero displacement within their working
body (s=0). Since there is no displacement within the device it is
reasonable to say that there is no energy storage or absorption in
the device. Such devices act to transfer and not absorb energy from
the joint. By contrast the natural joint is not a rigid body but is
comprised of elements of different compliance characteristics such
as bone, cartilage, synovial fluid, muscles, tendons, ligaments,
etc. as described above. These dynamic elements act to both
transfer and absorb energy about the joint. For example cartilage
compresses under applied force and therefore the resultant force
displacement product represents the energy absorbed by cartilage.
In addition cartilage has a non linear force displacement behavior
and is considered viscoelastic. Such systems not only absorb and
store, but additionally act to dissipate energy.
[0030] Approaches for surgically implanting extra-articular
mechanical energy absorbing apparatus have been developed. As
precise and effective placement are critical to the efficacy of an
implanted extra-articular mechanical absorbing apparatus, further
advancements in patient preparation and device-to-anatomy
juxapositional relationships have been found to be both useful and
necessary.
[0031] Therefore, what is needed are further refinements and other
approaches to properly and effectively implant energy absorbing
apparatus.
[0032] The present invention satisfies these and other needs.
SUMMARY OF THE DISCLOSURE
[0033] Briefly and in general terms, the present disclosure is
directed towards a surgical procedure for implanting a medical
device. More particularly, the procedure involves placement of an
extra-articular mechanical energy absorbing apparatus across
anatomy being treated. In one aspect, the energy absorbing
apparatus is placed across an articulating joint.
[0034] In one embodiment, the contemplated approach involves one or
more of patient preparation, identification of device position
relative to anatomy, structure of proper device components and
device implantation. Various devices and implantation aids are
disclosed to accomplish effective and proper placement of a medical
device.
[0035] In one contemplated approach, the position of the patient
and treatment areas are selected for easy access and to achieve
proper alignment at an implantation site. Use of vacuum lock
supports and arch bed structure accomplishes desired treatment site
stabilization and orientation. An adjustable surgical table also
facilitates desired positioning.
[0036] Moreover, in various contemplated approaches, guide
structures are configured adjacent a treatment site to aid in
identifying a proper juxtapositional relationship between patient
body anatomy and mechanical energy absorbing apparatus. In one
particular aspect, guide structures can be embodied in a
multi-directional center of rotation locator configured to identify
a center of rotation of an articulating limb. Further, remote
visualization as well as templates are contemplated for use in both
identifying device-to-anatomy mounting locations as well as
incision sites. Further, anatomical references can be used to
locate the center of rotation, and the target location can be
manually positioned by referencing these anatomical references.
[0037] In further contemplated approaches, proper size and
configuration of components of the mechanical energy absorbing
apparatus involves understanding the anatomy of the treatment area
as well as the unique characteristics of the anatomy of the
patient. When the energy absorbing apparatus includes one or more
bases which are to be fixed to a bone, such bases are selected to
provide surfaces which approximate the bone to which it is to be
attached and includes desired separation from the bone to provide
connecting structure. In this regard, remote sizing devices and a
direct physical inspection of the anatomy is undertaken.
Furthermore, fixed distance links, dummy links and base locating
tools are employed to facilitate both selection of base
implantation sites and proper component identification.
[0038] Assemblies for preparing bone mount sites and providing
access thereto are used in contemplated implantable procedures.
Structure in the form of base trials are used to identify and
initiate device mounting and act as drill guides. Also, tools are
provided to connect various components of an energy absorbing
apparatus at the treatment site. Kirscher wires (K-wires) and
Steinmann pins are employed to help maintain alignment of
components within the interventional site. In the art, "Kirscher
wire" or "K-wire" is generally used to refer to wires up to 2 mm in
diameter. "Steinmann pin" is generally used to refer to wires above
2 mm in diameter. For the purpose of this application, the term
"K-wire" is used generically to cover both Kirscher wires and
Steinmann pins. Both compression and locking screws are
contemplated for fixation purposes.
[0039] Moreover, an elongated handle with a distal attachment to a
component of an energy absorbing apparatus is contemplated to form
a tunnel or other access area at an interventional site as well as
to deliver components thereto. Devices and approaches are also
contemplated for advancing components through the tunnel formed
below a patient's skin and for both temporary fixation and
permanent assembly of parts. Post-implanted and post operative
examination is also contemplated to ensure proper operation of the
mechanical absorbing device.
[0040] The mechanical energy absorbing apparatus has the capacity
to absorb energy in addition to transfer energy from the joint.
Various joints of the body can be treated employing the systems and
methods of the present invention. In particular, articulating bones
involved in synovial joints can benefit from the present invention.
Accordingly, there are contemplated applications to the joints in
the knee, ankle, shoulder, hip, hand, wrist, elbow, mandible, and
foot.
[0041] In one specific embodiment, the presently disclosed
apparatus is embodied in a device utilizing an element, or elements
functioning as a unit, which responds to bending or changes in
elongation. Further, the device is used to reduce the loading
experienced by the articular surfaces of the tibiofemoral joint. In
one embodiment, the device is designed to reduce load on the joint
during knee extension with energy absorption. Joint load reduction
in this phase is governed by the compression of the
device--increased compression yields greater joint reduction. The
device is anchored in a position which ensures device elongation
resulting from knee flexion. As the knee moves into flexion, the
device is un-compressed and will cause little to no joint load
changes. The device may have other features which ensure correct
device alignment, and prevent against buckling, as the device
transitions into a compressed state. The device can also be
configured to provide joint load reductions during flexion or
throughout the nearly full range of motion.
[0042] Other features of the present disclosure will become
apparent from the following detailed description, taken in
conjunction with the accompanying drawings, which illustrate, by
way of example, the principles of the approach.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] FIG. 1 is a perspective view, depicting a patient position
for an interventional procedure;
[0044] FIG. 1A is a perspective view, depicting an alternative
positioning for a patient;
[0045] FIG. 2 is a perspective view, depicting an alternate
approach for securing a limb of a patient;
[0046] FIG. 3 is a cross-sectional view taken along lines 3-3,
depicting apparatus of FIG. 2;
[0047] FIG. 4 is a top view, depicting a patient on a surgical
platform;
[0048] FIG. 5 is a side view, depicting further control of the
device shown in FIG. 4;
[0049] FIG. 6 is a top view, depicting one approach for identifying
target patient anatomy;
[0050] FIG. 6A is is a perspective view, depicting a target
location on a patient's anatomy;
[0051] FIG. 7 is a side view, depicting use of a target for
placement of a first K-wire into a femur;
[0052] FIG. 8 is a side view, depicting placement of a K-wire into
a femur;
[0053] FIG. 9 is a perspective view, depicting use of a femoral
guide;
[0054] FIG. 10A is a side view, depicting use of the femoral guide
of FIG. 9;
[0055] FIG. 10B is a side view, depicting further use of the
femoral guide;
[0056] FIG. 11 is a side view, depicting an alternative embodiment
of a guide;
[0057] FIG. 12 is a perspective view, depicting an elongate holder
apparatus;
[0058] FIG. 13 is a perspective view, depicting the elongate holder
apparatus positioned over body anatomy;
[0059] FIG. 14 is a side view, depicting the holder apparatus
positioned over body anatomy;
[0060] FIG. 15 is a side view, depicting target structure of the
elongate holder apparatus;
[0061] FIG. 16 is a perspective view, depicting a guide for
approximating a center of rotation location of an articulating
member;
[0062] FIG. 17 is a side view, depicting a first step in employing
the guide of FIG. 16;
[0063] FIG. 18 is a side view, depicting a subsequent use of the
guide of FIG. 16;
[0064] FIG. 19 is a side view, depicting further operation of the
guide of FIG. 18;
[0065] FIG. 20 is a side view, depicting use of a link in
combination with the guide of FIG. 19;
[0066] FIG. 21 is a side view, depicting yet further use of the
guide of FIG. 20;
[0067] FIG. 22 is a side view, depicting body anatomy with the
guide of FIG. 21 removed;
[0068] FIG. 23 is a perspective view, depicting use of a femoral
base trial;
[0069] FIG. 24 is a perspective view, depicting gaining access to
an implantation site;
[0070] FIG. 25 is a perspective view, depicting placing a base
component on a femur;
[0071] FIG. 26 is a perspective view, depicting attachment of a
base to a femur;
[0072] FIG. 26A is a perspective view, depicting a femoral
placement guide;
[0073] FIG. 26B is a perspective view, depicting a locking screw
guide;
[0074] FIG. 27 is a side view, depicting a second approach to a
template for a use at an interventional site;
[0075] FIG. 28 is a side view, depicting second embodiment of a
template for use at an interventional site;
[0076] FIG. 29 is a perspective view, depicting the template of
FIG. 27 adjacent body anatomy;
[0077] FIG. 30 is a perspective view, depicting physical
examination of a mounting site within a patient's anatomy;
[0078] FIG. 31 is a perspective view, depicting use of a retractor
at an interventional site;
[0079] FIG. 32 is a perspective view, depicting use of a base trial
at an interventional site;
[0080] FIG. 33 is a perspective view, depicting further use of the
base trial at the interventional site;
[0081] FIG. 34 is a perspective view, depicting the interventional
site with the trial base of FIG. 24 removed;
[0082] FIG. 35 is a perspective view, depicting placement of a
first base component adjacent body anatomy;
[0083] FIG. 36 is a perspective view, depicting a tool shaped for
attaching a socket mount to a base component;
[0084] FIG. 37 is a perspective view, depicting a base component
placed at an interventional site;
[0085] FIG. 38 is a perspective view, depicting use of a drill
guide at the interventional site;
[0086] FIG. 39 is a perspective view, depicting attaching a base
component at an interventional site using fastening devices;
[0087] FIG. 40 is a perspective view, depicting forming a tunnel
beneath the skin;
[0088] FIG. 41 is a perspective view, depicting the femur and tibia
with a femoral base and an absorber unit;
[0089] FIG. 42 is a perspective view, depicting forming a space for
a tibia base component;
[0090] FIG. 43 is a perspective view, depicting attaching a tibia
base to an absorber;
[0091] FIG. 44 is a perspective view, depicting the tibia with a
base attached thereto;
[0092] FIG. 45 is a perspective view, depicting manipulation of a
sheath surrounding an absorber;
[0093] FIG. 46 is a perspective view, depicting physical inspection
of a second mounting site at an interventional site of a
patient;
[0094] FIG. 47 is a perspective view, depicting a retractor
providing access to the second mounting site depicted in FIG.
46;
[0095] FIG. 48 is a partial cross-sectional view, depicting a dummy
link assembly;
[0096] FIG. 49 is a partial cross-sectional view, depicting
attachment of one end of the dummy link assembly of FIG. 48 to a
first base;
[0097] FIG. 50 is a partial cross-sectional view, depicting
attachment of a second base component to a second end of the dummy
link assembly of FIG. 49;
[0098] FIG. 51 is a perspective view, depicting a fixed distance
link;
[0099] FIG. 52 is a perspective view, depicting the fixed distance
link of FIG. 51 attached to a distal end of a handle assembly;
[0100] FIG. 53 is a perspective view, depicting the arrangement of
FIG. 52 further including a cover installed on a distal end of the
fixed distance link;
[0101] FIG. 54 is a perspective view, depicting use of the assembly
of FIG. 53 at an interventional site;
[0102] FIG. 55 is a perspective view, depicting placement of the
fixed distance link to a first base;
[0103] FIG. 56 is a perspective view, depicting use of a drill
guide in combination with a second base at an interventional
site;
[0104] FIG. 57 is a perspective view, depicting fastening the
second base at the interventional site;
[0105] FIG. 58 is a partial cross-sectional view, depicting
rotation of one articulating body member;
[0106] FIG. 59 is a partial cross-sectional view, depicting removal
of a dummy link from the interventional site;
[0107] FIG. 60 is a top view of a base locating tool;
[0108] FIG. 61 is a side view, depicting the base locating tool of
FIG. 60;
[0109] FIG. 62 is a perspective view, depicting a first step in a
method involving the base locating tool;
[0110] FIG. 63 is a perspective view, depicting a subsequent step
involving the base locating tool;
[0111] FIG. 64 is a perspective view, depicting yet another step
involving the base locating tool;
[0112] FIG. 65 is a perspective view, depicting further use of the
base locating tool at an interventional site;
[0113] FIG. 66 is a perspective view, depicting removal of the base
locating tool from an interventional site;
[0114] FIG. 67 is a cross-sectional view, depicting a link stored
within a guide tube housing;
[0115] FIG. 68 is a partial cross-sectional view, depicting use of
the guide tube assembly of FIG. 67 at an interventional site;
[0116] FIG. 69 is a partial cross-sectional view, depicting an
attachment of the link assembly to a first base component;
[0117] FIG. 70 is an enlarged view, depicting a connection between
a link assembly and a base component;
[0118] FIG. 71 is a side view, depicting a link assembly including
socket locks;
[0119] FIG. 72 is a partial cross-sectional view, depicting
configuring a portion of a sheath about a portion of a first base
component;
[0120] FIG. 73 is a partial cross-sectional view, depicting
placement of a portion of a sheath about a portion of a second
based component;
[0121] FIG. 74 is a perspective view, depicting a tool for
temporarily attaching to a mount;
[0122] FIG. 75 is a perspective view, depicting a tool for locking
a link assembly to a mount;
[0123] FIG. 76 is a perspective view, depicting another tool for
accomplishing attachment of a link to a base;
[0124] FIG. 77 is a perspective view, depicting an additional
approach to a tool for assembling a mechanical energy absorbing
apparatus;
[0125] FIG. 78 is a perspective view, depicting the tool of FIG. 77
with a handle removed;
[0126] FIG. 79 is a perspective view, depicting the tool of FIG. 78
with a socket loading tool removed;
[0127] FIG. 80 is a non-sectional view, depicting another approach
to an attachment tool;
[0128] FIG. 81 is a perspective view, depicting an exterior of body
anatomy having mechanical energy absorbing apparatus implanted
therein.
DETAILED DESCRIPTION
[0129] Referring now to the drawings, which are provided by way of
example and not limitation, the present disclosure is directed
towards apparatus for treating body tissues. In applications
relating to the treatment of body joints, the described approach
seeks to alleviate pain associated with the function of diseased or
malaligned members forming a body joint. Whereas the present
invention is particularly suited to address issues associated with
osteoarthritis, the energy manipulation accomplished by the present
invention lends itself well to broader applications. Moreover, the
present invention is particularly suited to treating synovial
joints such as the knee, finger, wrist, ankle and shoulder.
[0130] In one particular aspect, the presently disclosed method
seeks to permit and complement the unique articulating motion of
the members defining a body joint of a patient while simultaneously
manipulating energy being experienced by both cartilage and osseous
tissue (cancellous and cortical bone). Approaches involving varying
energy absorption and transfer during the rotation of the joint and
selecting a geometry for the energy absorption assembly to provide
necessary flexibility are implemented into various embodiments of
the present invention. Certain of the embodiments include geometry
which accomplishes variable energy absorption designed to minimize
and complement the dampening effect and energy absorption provided
by the anatomy of the body, such as that found at a body joint. It
has been postulated that to minimize pain, in an osteoarthritic
joint absorption of 1-40% of forces, in varying degrees, may be
necessary. Variable absorption in the range of 5-20% can be a
target for certain applications. In certain specific applications,
temporary distraction (e.g., less than 3 months) is employed in the
energy manipulation approach.
[0131] Conventional or surgical or minimally invasive approaches
are taken to gain access to a body joint or other anatomy requiring
attention. Arthroscopic approaches are thus contemplated when
reasonable to both implant the energy manipulation assembly as well
as to accomplish adjusting an implanted assembly. Moreover,
biologically inert materials of various kinds can be employed in
constructing the energy manipulation assemblies of the present
invention.
[0132] In one approach for treating a knee, an implantable
extra-articular absorber is designed to reduce medial compartment
loads of the knee. The absorber system is comprised of two
contoured base components, a kinematic load absorber and a set of
bone screws. The implanted system is both extra articular and extra
capsular and resides in the subcutaneous tissue on the medial
aspect of the knee. The device is inserted through two small
incisions superior to the medial femoral condyle and inferior to
the tibial plateau. The contoured base components are fixed to the
medial cortices of the femur and tibia using bone screws.
[0133] The femoral and tibial base components are contoured to
ensure optimal fit to the bony surfaces and are plasma sprayed and
coated with hydroxyapatite on bone contacting surfaces to promote
bony ingrowth and enhance osteointegration. The orthopedic bone
screws provide immediate fixation of the base components to the
bone during osteointegration.
[0134] The kinematic absorber is attached to the base components
between two mobile ball and socket joints. It is comprised of two
helically wound springs on a sliding stabilizer. The springs act to
absorb load from the medial compartment of the knee while the
sliding stabilizer and the ball/sockets allow the device to
accommodate full knee range of motion.
[0135] The load bypassing knee support system is indicated for
patients suffering with medial knee pain secondary to
osteoarthritis who have failed medical treatments.
[0136] It is contemplated that the absorber system is supplied
packaged in a set of individually sealed Tyvek/film pouches. The
base components and absorber assemblies will each be individually
packaged and labeled. Moreover, the load bypassing knee support
system and all its components are provided sterile and are not
intended for reuse/re-sterilization by the user. These devices are
sterilized using EtO. Surgical instruments, positioning and locking
instruments must be sterilized using normal hospital orthopedic
instrument sterilization methods.
[0137] In one particular approach, turning now to FIGS. 1-5, there
are shown various apparatus for positioning a patient and preparing
the patient for an interventional procedure. Although the disclosed
apparatus can be configured for use in various procedures, for
purposes of illustration, the apparatus have been depicted in
conjunction with treatment of a leg 100 of a patient 102. For such
a procedure, the patient 102 is placed upon a surgical table 104 in
a lateral decubitus position with the patient 102 laying generally
on his or her side as shown in FIG. 1. Alternatively, depending on
surgeon preference, the patient can be placed in a supine position
with an ability to flex the knee (See FIG. 1A).
[0138] While in a lateral decubitus position, a top leg 106 of the
patient 102 is flexed forward at the hip 108. A medial side 110 of
the bottom leg 112 is exposed and in full extension. Fluoroscopic
imagery is utilized to ensure that the knee is in full extension
and in a true lateral position. The operating table may be
airplaned and/or moved into slight trendelenberg or reverse
trendelenberg to assist in obtaining and maintaining true lateral
knee fluoroscopy. Any gap between the medial condyles of the
articulating bone structure of the leg is closed by supporting a
lateral side of the distal tibia of the bottom leg 112. In this
regard, an arch bed 114 can be provided to help properly align the
bottom leg 112. The arch bed 114 can further include a post 116 to
which interventional tools can be mounted.
[0139] The patient and limb can be stabilized with a bean bag or
peg board per physician preference. Moreover, the upper leg 106 can
be supported by a vacuum lock support 118. The vacuum lock support
118 can be configured to assume a desired shape and subsequently be
locked into the desired shape during the interventional procedure.
The vacuum lock support 118 structure can also be employed to
support other areas of the patient including the lower leg 100 as
shown in FIG. 1. Where such structure is utilized, a femoral side
of the lower leg 100 should be locked throughout the procedure,
whereas the tibial side should be able to be locked and unlocked to
allow for rotation. Various angulations of the limbs are necessary
during tibial base component fixation and full flexion knee motions
must be available.
[0140] Once the limbs of the patient are properly positioned, the
interventional area is cleaned and shaved as necessary. The entire
leg, thigh through foot should be prepared. Under fluoroscopy or
other remote imaging means 120, femoral condyles (not shown) are
aligned by pivoting the table 104 with table adjustment controls
and to again ensure a true lateral view. As shown in FIGS. 4 and 5,
the table 104 can be rotated laterally to align posterior condyles
and can be rotated longitudinally to align inferior condyles. When
necessary, the table 104 can also be rotated along a third axis of
rotation to achieve proper leg position-to-remote viewing
orientation. Alternatively, the flouroscopy can be rotated to
ensure a true lateral view.
[0141] During the interventional procedure, the operative
articulating knee joint and foot of the patient 102 should be
completely exposed and configured outside a drape covering the
patient 102. The knee should be free to flex and extend as needed
and preferably up to 135.degree. of flexion. Again, any medial
condyle gap should be closed by supporting the lateral side of the
distal tibia and/or ankle. Once the physician is satisfied with leg
positioning and preparation, using palpation to define bone
position, tibia and femur base contours are traced onto the skin
with a surgical marker.
[0142] In one approach, with reference to FIG. 6, an initial step
in treatment involves identifying a patient's Blumensaat's line,
which is a structural feature of a femur. With the patient laying
on a surgical table as described above with respect to FIG. 1,
fluoroscopy or other remote imaging techniques are used to view the
anatomy of the lower leg 112. A leveling guide and platform
assembly 122 is provided and clamped to the table 104. The platform
122 includes a bubble level 124 to aid in leveling the platform 122
relative to the leg 112. After proper orientation of the platform
122 is obtained, and a K-wire guide portion of the platform
assembly is positioned as necessary above the patient's
Blumensaat's line, the platform 122 is locked into position. The
K-wire guide portion 126 of the platform assembly 122 is then
employed as a guide through which a K-wire 130 (shown as a point in
FIG. 6) is inserted and driven through tissue and into underlying
bone at the Blumensaat's line. Additionally, anatomical landmarks
(e.g., center of Blumensaat's line, inferior and posterior regions
of the femoral condyles) can aid in manually positioning a K-wire
in the target location and oriented lateral to the fluoroscopic
view using the bulls-eye instrument. So positioning the K-wire aids
in subsequently positioning a mechanical energy absorbing structure
across a joint. This necessarily involves identifying a center of
rotation of the femur. In one approach, the center of rotation is
assumed or determined to be at a midpoint of Blumensaat's line.
Other approaches recognize that the center of rotation is displaced
from the midpoint of Blumensaat's line. As shown in FIG. 6A, using
Blumensaat's line as an anatomical landmark, an acceptable region
and target location 125 can be identified for placement of a center
of a femoral socket (not shown).
[0143] In a preferred alternative approach, a femoral location for
an energy manipulation device is identified. Palpation of the
medial epicondyle allows a physician to find the recess/sulcus of
the epicondyle which is considered the center of rotation of the
knee. Alternatively, you can find the insertion of the MCL and that
is considered the center of the knee rotation. First, a physician
palpates the medial epicondyle and positions a K-wire antero
proximal to the midpoint of Blumensaat's line 131 (See FIGS. 7 and
8). Using a bulls-eye instrument 133, a 2.4 mm K-wire 135 is
inserted perpendicular to the lateral view of a femur 137. Care is
taken to achieve accuracy as poor positioning of K-wires may lead
to inappropriate placement and malfunction of an implanted
device.
[0144] Next, with reference to FIGS. 9 and 10A, B, a femoral guide
139 is employed to accurately identify the femoral center of
rotation. A moveable hole 141 in the femoral guide 139 is slid over
the implanted K-wire 135. Under fluoroscopy, a physician determines
which arc 143 on the guide 139 best fits the inferior and posterior
regions of the femoral condyle. The selected arc is then aligned
with the condylar curve. If the condylar curve falls between two
arcs, the larger arc is selected. While maintaining arc alignment,
a second K-wire 145 is drilled through a center hole 147 of the
guide 139 (See FIG. 10B). Alternatively, a circle guide can be
used. The circle guide can be, but is not limited to, the following
forms: a series of concentric full circles or a series of
concentric arcs (e.g., 90 deg, 140 deg, 135 deg) designed to match
the posterior & inferior femoral region of femoral condyle.
[0145] Another form of the circle guide is a laminate applied to
the fluoroscopic screen that the physician is viewing. Once the
lateral view is achieved, patient position is maintained, and a
laminate guide is attached to the fluoroscopic screen. The arcs or
curves or circles of the laminate are positioned to align with the
posterior and inferior regions of the femoral condyle.
Magnification of fluoro can aide in this process. The laminate
directly identifies the target location, and the physician inserts
a K-wire into this target location on the patient by matching the
location of the K-wire on the patient's anatomy to achieve the
designated location shown by the target marker on the fluoro screen
laminate. Further, the circle guide can be incorporated into the
fluoroscopic screen (as part of the computer image) to simplify
positioning of the arcs to the condyles on fluoro.
[0146] Additionally, a circle guide on the opposite side of the
joint as that being operated provides an alternative means of
finding the target location. This contralateral location provides
the added benefit that distance of the guide from the joint
(variable among patients due to the thickness of the soft tissue in
this region) results in proportional magnification of the arcs
relative to the condyles. Further, a combination of top and bottom
circle guides can be employed
[0147] The femoral guide 139 is then rotated until a straight line
149 extending across a portion of the guide 139 is aligned parallel
to the femoral shaft 137. A third K-wire 151 is next drilled into
an offset hole 153. Thereafter, the previously placed K-wires 135,
147 are removed as is the femoral guide 139, leaving the third
K-wire in situ. The position of the third K-wire is used
subsequently for accurate placement of a femoral rotational
component of an energy manipulation assembly.
[0148] One specific approach to an alternate design of a guide is
shown in FIG. 11. Here, the guide 159 is configured for a left knee
but other embodiments can be employed for other anatomy such as the
right knee. The guide 159 also includes a center hole for receiving
a K-wire and further embodies arcs (not shown) which show up under
flouroscopy. The arcs can similarly facilitate alignment with local
anatomy and the ultimate positioning of a rotational component of
an energy manipulation assembly.
[0149] In yet another alternative approach, as shown in FIGS.
12-22, an initial step in an interventional procedure involving
implanting a mechanical energy absorbing structure includes
approximating a femoral location. Here, an elongate handle 132
including an arm 134 configured at its distal end is provided and
configured to engage a mid-section of a 2.4 mm K-wire 136 to ensure
accurate trajectory. A proximal end 138 is mounted to the surgical
table as described previously. The K-wire 136 is positioned
perpendicularly and above a femur 137 (See FIG. 13) and is
positioned in an upper left quadrant (See FIG. 14) of an image
provided by a remote viewing device such as that described above.
The C-arm 134 is further equipped with a bulls-eye structure 140 to
aid in properly positioning the K-wire within the desired quadrant.
A fluoroscopic view of the bulls eye 140 and K-wire 136 is shown in
FIG. 15. The K-wire is then fixedly advanced within the femur 137
for use in further aspects of the center of rotation location
procedure.
[0150] Next, a right-angle guide 142 is provided to cooperate with
the K-wire 136. For this particular application, a left knee guide
142 is provided but it is to be understood that various other
guides such as those for a right knee or for other articulating
joints can also be implemented.
[0151] The right angle guide 142 includes a pair of sliding members
144 each of which are received in respective channels 146 arranged
orthogonally to arms 148 defining the guide 142. Knobs 150 are
further provided to accomplish translating the sliding members 144
along the channels 146. Moreover, knobs 157 are provided to effect
movement of the channels along arms 148. Additionally, the channels
146 include one component 152 of a cross-hair 154 while the sliding
members 144 include a second component 156 of a cross-hair 156 (See
FIG. 19). The guide 142 is also equipped with a K-wire receiving
hole 158 arranged perpendicularly to front and back faces of the
guide 142.
[0152] In use, tack-wire receiving hole 158 of the guide 142 is
placed over the K-wire 136 so that the guide is placed adjacent the
leg of the patient. The guide 142 is then rotated about the K-wire
136 to align the guide 142 with a longitudinal axis of the femur
137. An optional axis guide (not shown) can be used to aid in
alignment with the longitudinal axis. A second K-wire 160 is placed
in a second through hole 162 formed in the guide 142 to fix the
rotation of the guide 142 (See FIGS. 17 and 18).
[0153] The cross hairs 154 are then aligned tangent and coincident
to posterior and inferior condyles of the bones of the articulation
joint (See FIG. 19). This is accomplished by rotating knobs 150 and
157 to move the channel 146 and slider 144 within the channel 146.
Proper positioning of the cross-hair is accomplished through remote
imaging techniques.
[0154] Thereafter, a linkage 164 is selected from a line of
available, variably dimensioned linkages and is placed into
engagement with the sliders 144. Notably, the links define a
generally right angle device with terminal ends equipped with holes
for receiving posts 166 extending from the sliders 144 (See FIG.
21).
[0155] The linkage 164 further includes a K-wire receiving through
hole 168 positioned at a junction between arms which define the
linkage 164. This through hole lies above the femoral center of
rotation. A further K-wire 170 is inserted through this hole 168
and fixedly attached to the femur 137 as shown in FIG. 22.
Thereafter the linkage assembly 164 is removed along with the
previously placed K-wires 136, 160.
[0156] An alternative form of targeting can be used, involving the
linkage apparatus with an electronic readout of absorber length.
Optimal position can be determined by moving the target location
until the readout in extension and flexion provide the appropriate
change. This can be aided using a set of rules guiding how to
adjust position based on the readout results of the previous
position.
[0157] Once the third K-wire 151 (FIG. 11) or K-wire 170 of FIG. 22
is placed at the center of rotation, the next challenge becomes
identifying the areas for mounting components of a mechanical
energy absorbing system. In one approach, a femoral base trial
component 171 is slid over the remaining third K-wire 151 (See FIG.
23). The base trial 171 includes a connector mount 173 which
references the K-wire 151. A 3-5 cm incision from the K-wire 151
extending along the posterior edge of the trial base component 171
is then made (See FIG. 24). Using blunt dissection, the vastus
medialus is elevated and retracted anteriorly and laterally to
provide sufficient bone exposure to enable adequate removal of
periosteum 177 and base component placement. To accomplish this, a
periosteum elevator 179 can be employed.
[0158] It is to be recognized that inadequate retraction of the
muscle groups and exposure of bone may lead to poor visibility of
the region and hinder base implant size selection and periostium
removal. Moreover, it must be borne in mind that the medial
superior genicular artery may cross the operative field just above
the knee. If so, it should be protected, ligated or coagulated to
avoid postoperative hematoma.
[0159] Next the trial femoral base component 171 is slid over the
K-wire 151 and the fit is checked to determine if a continuous
apposition of the base to bone exists around edges. Efforts are
made to avoid the application of excessive force to preserve
registration of the distal end K-wire location. Various templates
are utilized to select a preferred base component. Sizing and
positioning can be confirmed by using remote imaging (fluoroscopy)
as well as a gap sizing tool (not shown) to ensure that a majority
of the base component edge is secured against the bone with an
acceptable minimum distance in any gap areas.
[0160] If osteointegration is required the base component should
make intimate contact with the bone surface. In this case, the
periostium in contacting regions of the femoral base can be removed
using a blade, curette or the periosteal elevator 179. It is to be
ensured that a sufficient region of periosteum is removed or
retracted to provide intimate contact between an entire base
component surface and bone. Further, when possible, the periostium
should be pulled back so that it can be repositioned over the base
component once the base has been attached. Here, measures are taken
to avoid inadequate removal of periosteum as the same may prevent
osteointegration of the bone into the base component. Moreover,
excessive removal of periosteum beyond the base component margins
should be avoided as that may reduce the bloody supply to the
bone.
[0161] Once a preferred base component is selected, it is removed
from its packaging and visually inspected for any obvious defects.
If visual defects are observed another like part is selected. As
shown in FIG. 25, the base component 190 is then placed on the
prepared femoral bone 137 by sliding the ball and socket 191 over
the femoral K-wire 151. At this point, a temporary ball and socket
affixed to the base can be employed. Thereafter, two stabilizing
K-wires are drilled into the available holes on the base component
to maintain implant positioning. It is to be noted that slight
adjustments in position of the base component at this point will
assist in seating the base component on the bone and aid finding
the best fit between the base component and the bone. Movements
should be gently executed to preserve registration of the distal
end K-wire location and protect the osteointegration surface.
[0162] Turning now to FIG. 26, the fixation of the base components
to bone can begin, starting with the proximal 3.5 mm bicortical
compression screws 193. An appropriate drill bit and drill guide
are selected. Then screw length is determined by measuring drill
holes with a depth gauge in standard fashion. In one approach,
assurances should be made so that both cortices are captured by the
compression screws 193. To ensure that the base 190 stays at a
correct location relative to the K-wire 151 while the base 190 is
attached to bone, a femoral placement guide 197a can be employed
(See FIG. 26A). The guide 197a is configured to be temporarily
attached to the base 190 and later removed when the base attachment
is completed.
[0163] After placing the first bi-cortical screw 193 to the desired
tightness, a gap sizing tool (not shown) can be used to ensure that
the base 190 is properly positioned and that no new gaps have
formed. If the gap sizing tool indicates an unacceptable gap, the
base component must be repositioned or osteointegration may not
occur properly. This procedure is repeated for the second 3.5 mm
bicortical 193 and 6.5 mm unicortical compression 195 screws. All
three compression screws are tightened to their final setting
before initiating locking screw placement. The two K-wires are
removed from the base component 190. A further verification is made
at this time to ensure that the target K-wire 151 has not been bent
or moved. It is to be noted that the compression screws 193, 195
should be inserted and fixed prior to initiation of the locking
screws to ensure good compression of the base component 190 onto
the femur 137, thereby maximizing osteointegration.
[0164] Next, in order to place locking screws 197, the correct
drill bit and threaded drill guide 197a (See FIG. 26B) are
selected, such as for 5.0 mm locking screws. The locking drill
guide is threaded into the base component 190. A pilot hole is
drilled while ensuring minimal disturbance to the base component
190. The locking screw 197 is then screwed in place to the
specified tightness (such as 4 Nm torque). This procedure is
repeated for the second locking screw 197. The locking screws are
positioned in the area of the base component that is raised off of
the bone surface. The locking of the screws to the base in this
region and then extending into the bone create a rigid structure to
minimize movement of the base.
[0165] In a second approach (See FIG. 27), a plastic template 172
is placed over the patient's leg 175 in the area where the
interventional implantation procedure is to occur. Starting base
component sizes F.sub.1 and T.sub.1 and a link component C.sub.1
are roughly approximated to a patient's anatomy. A pen or other
marker is used to outline appropriate base sizes 176. Perforated
outlines can allow for directly marking a patient's skin. Incision
lines (not shown) can also be made in the area.
[0166] With reference to FIGS. 28 and 29, an alternative approach
to a template 178 is depicted. This second approach involves an
articulating assembly having a middle section 180 which
approximates a link component, the middle section 180 having ends
to which curved, elongate hoops 182, 184 are rotatably connected.
The hoops 182, 184 have a length and shape approximating base
components to be used on opposite sides of an articulating joint,
such as a knee joint.
[0167] At the point of connection between the middle section 180
and a first elongate hoop 182, there is configured a guide 184
having a through hole sized to receive the K-wire 120 placed at a
patient's anatomy center of rotation. Accordingly, the articulating
template 178 is placed adjacent a patient's skin in the area of the
implantable site to thereby provide structure for facilitating
selection of proper components for a mechanical energy absorbing
assembly. Again, marks 176 can be made on a patient's skin to map
out a desired component shape and orientation, as well as to
identify a location for initial incisions.
[0168] After making a first incision 186 within the mapped area,
tissue is dissected to the bone. As shown in FIGS. 30 and 31, in an
application to the knee joint, the first incision 186 is made
through skin and tissue coincident with the femur. The dissection
is made vertically or longitudinally along the leg 175 and is made
along natural tissue planes, posterior to the vastus medialus
muscle (not shown). The underlying periostium is elevated and
removed as necessary while employing standard surgical techniques
and an effort is made to avoid disrupting the joint capsule. To
prepare the implantation site, access is provided by a
scissor-action retractor 188. When possible, the periosteum should
be pulled back so that it can be repositioned over the base
component once the base has been attached.
[0169] In most instances, an one inch incision on a femoral side of
a knee joint is adequate. A tissue dilator or the surgeon's finger
can be used for blunt dissection of tissue from the periostium in
an area where a base component would be placed and extending to and
beyond the point where the K-wire 170 is affixed to bone. The
femoral base component 190 is test fitted based upon contact area
with the bone and clearance from periostium. In this way, the
general contour of a desirable femoral base component can be
identified. The base component 190 is then removed from the
area.
[0170] With reference to FIGS. 32 and 33, in one approach, a next
step can include employing a base trial 192 to create initial
mounting holes for a base component 190. The base trial 192 to be
used can be one of a number of available trials and the selected
trial 192 will embody a base component portion 194 having a shape
and size approximating that previously identified as being
desirable. Alternatively, the base trial itself can be used in
place of a previously described series of steps to identify proper
contour of the base 190. Extending vertically from the base
component portion 194 are a plurality of tubes 196, each sized to
receive a single K-wire 198. Attached to upper ends of the tubes
196 is an arm, a laterally displaced end of which defines a disk
200 having a hole 202 extending therethrough and being sized to
receive the K-wire placed, in the present example, at the femur
center of rotation. This disk 210 allows the trial 192 to move in
three dimensions.
[0171] After sliding the disk 200 of the base trial 192 over and
along the K-wire 170, the base component portion 194 is placed
adjacent bone. Next, the K-wires 198 are inserted through the tubes
196 and fixedly inserted into the femur (See FIG. 34). The K-wire
120 placed at the center of rotation is then removed. The base
trial 192 is then also removed from the interventional site and a
properly sized base component 190 including holes for receiving the
K-wires 198 is placed against bone using the K-wires 198 as a guide
for proper placement. In an alternative approach, a K-wire with a
non-round shape (for example, triangular or square) with a matching
hole on the base component 190 can be used in place of two K-wires.
The non-round shape keeps the base component in the proper
orientation.
[0172] Once placed against bone, mounting access holes 204 formed
in the bone component 190 are employed to drill holes into
underlying bone. Screws (not shown) are then used to affix the base
component 190 in the desired orientation and the K-wires 198 are
removed from the area.
[0173] In another approach, as shown in FIGS. 36-39, a base
component 190 can alternatively be placed against a cleared surface
on the bone, guidance therefor being provided by the K-wire 170
placed at a center of rotation. A component clamping tool 206 is
employed to affix a K-wire socket 208 to the base 190, in the event
the base 190 lacks such structure. One or more forms of this
component clamping tool 206 is contemplated to be used to also
subsequently assemble other components of the mechanical energy
absorbing device in situ. Various temporary K-wire sockets can be
used to match the K-wire hole at the center of rotation dependent
on where the base component 190 best fits on the bone.
[0174] A femoral drill guide 210 is then used to provide a guide
for directly attaching holes through the base component 190 and
into bone at desired angles (See FIG. 29). Such desired angles are
selected to achieve necessary affixation of the base 190 to the
bone as dictated by the patient's anatomy as well as load carrying
requirements. The base component is then affixed to bone as shown
in FIG. 30.
[0175] After the first base component 190 is attached to bone and
the temporary K-wire socket is removed from the base, various
approaches can be employed to assemble in situ the remaining
components of an energy manipulating system. In one preferred
approach, a first step involves creating an absorber tunnel. A
distance of approximately 60 mm is measured from the femoral K-wire
151 along the direction of the tibial shaft. A 2-4 cm incision 191,
beginning at the 60 mm mark is made and extends inferior along the
tibial shaft. With reference to FIG. 40, using blunt dissection
such as by the physician's finger or a tissue dilator, an
extracapsular tunnel 193 for an absorber unit is formed beneath the
skin and through soft tissue that extends from femoral to tibial
incisions. The physician then ensures that the channel is free of
fibrous attachments and can accommodate the absorber element. A
clear and continuous channel should exist between the femoral base
component an expected location for a tibial base component.
Alternatively, the incision can be extended across the entire
length to avoid tunneling. The energy manipulating system can be
pushed or pulled through the tunnel between the two incisions. The
energy manipulating system can be temporarily housed in a sheath or
a dilating introducer.
[0176] Since the infrapatellar branch of the saphenous nerve may be
located in this region, care should be taken to prevent injury to
this structure. Moreover, it is to be noted that the knee must be
in full extension during tibial positioning and attachment and the
gap between the femur and tibia should be closed by the physician
by applying a varus stress on the leg for a medial placement, a
valgus stress on the leg for a lateral placement, and an axial
stress on the leg for a bilateral placement of an absorber(s).
Failure to maintain this position may result in incorrect absorber
length, inadequate device function, or device failure. Next, using
fluoroscopy, the absorber unit 216 is positioned so that it is
perpendicular to the tibial plateau (See FIG. 41). It is to be
noted that the absorber unit can be configured within a sheath and
held in a compressed state, the ends of which can be folded during
and held back for initial implantation. A K-wire can be drilled
(not shown) at the neck of the ball to hold the absorber in this
alignment.
[0177] At this time, a tibial base component size is selected. As
shown in FIG. 42, the skin is retracted to provide sufficient bone
exposure for placement of the tibial base component. A tibial trial
base component (not shown) can be placed at the side to check the
fit (continuous apposition of base to bone is desired around
edges). Excessive force of placement should be avoided to preserve
integrity of the mounting location. Using sizing templates, the
preferred base component can be selected. Sizing should be
confirmed to ensure that a majority of the base component edge is
secured against the bone with an acceptable minimum distance in any
gap areas. These steps are taken while ensuring that absorber
alignment is maintained at all times. The periostium 197 is removed
in contacting regions of the tibial base using a blade, curette or
periosteal elevator 199. A sufficient region of periosteum should
be removed or retracted to provide intimate contact between the
entire base component surface and bone. It is to be recognized that
inadequate removal of periosteum may prevent osteointegration of
the bone into the base component. Moreover, excessive removal of
periosteum beyond the base component margins may reduce blood
supply to the bone. When possible, the periostium should be pulled
back so that it can be repositioned over the base component once
the base has been attached.
[0178] Once a proper sized tibial base is selected, it is removed
from its packaging and visually inspected for any obvious defects.
If visual defects are observed, another component is selected. The
tibial base 215 is then attached to the absorber 195 using an
assembly tool (See FIGS. 74-80).
[0179] As shown in FIG. 43, the base component 215 is then placed
onto the prepared tibial bone and it is readjusted to find the
optimal positioning. During tibial attachment, the knee should be
in full extension with varus stress for a medial placement. In
certain applications as for example those relating to knee, it has
been found to be beneficial to close a gap between the bones
forming a joint and then selecting an optimum position for
placement of the second base component. Further, varus or valgus
stresses can be applied to close the gap between the joint members.
In this way, the ultimate positioning of the second (tibial) base
will then involve ensuring that there will be sufficient space
between joint members when a complete extra-articular mechanical
energy absorbing apparatus is placed across the joint. Moreover,
slight adjustments in position of the tibial base component 215 at
this point will assist in seating the base component on the bone
and aid in finding the best fit between the base component and the
bone. Alignment of the absorber 195 must be maintained at all
times. Adjustments in base position should be gently executed to
protect the osteointegration surface on the base component. One or
more stabilization K-wires 217 can be drilled into the available
holes on the tibial base component 215 to maintain position.
[0180] The fixation of the tibial base component to the bone with
distal 3.5 mm compression screws 219 can now commence (See FIG.
44). An appropriate drill bit and drill guide (not shown) are
selected and a pilot hole is drilled in the area. Appropriate screw
lengths are then determined by measuring drill holes with a depth
gauge in standard fashion. Steps are taken to ensure that both
cortices are captured by the 3.5 mm compression screws.
[0181] After placing the first screw base to the desired tightness,
a gap sizing tool (not shown) can be used to ensure that the base
is properly positioned and that no new gaps have formed. If the gap
sizing tool indicates an unacceptable gap, the base component
should be repositioned. This procedure is repeated for the second
3.5 mm bicortical 219 and the 6.5 mm unicortical 221 compression
screws. The three compression screws should be inserted and fixed
prior to initiation of the 5.0 mm locking screws 223 to ensure good
compression of the base component onto the tibia, thereby
maximizing osteointegration. All of the compression screws are then
tightened to their final setting. The K-wire 217 is removed from
the tibial base component. A verification is made that the target
K-wire 151 has not bent or moved and that the absorber unit remains
aligned perpendicular to the tibial plateau.
[0182] The locking screws 223 are then selected. First, the correct
drill bit and threaded drill guide to produce the correct hole size
for the 5.0 mm locking screws is also selected. A locking drill
guide (not shown) is threaded into the tibial base component 715. A
pilot hole is then drilled while ensuring minimal disturbance to
the base component. The locking screws are screwed in place to the
specified tightness (about 4 Nm torque). This procedure is repeated
for the second locking screw 223.
[0183] The sheath 225 covering the internal components of the
longitudinally compressed absorber 216 is now released from its
folded back configuration. First, the absorber 216 is released by
cutting structures such as retention sutures or wires (not shown)
from the femoral side. This releases both the absorber and
retracted ePTFE sheath. The knee should be in extension during
absorber release. Next, the sheath is drawn over the mount and
adjacent base region until an affixation point of the hole in the
sheath aligns with the hole 227 in the base component. A split pin
can be inserted into the aligned hole to secure the sheath onto the
femoral base component. The procedure is repeated to attach sheath
to the tibial base component.
[0184] Thereafter, a final verification is conducted. Thus, after
placement, the knee should be rotated through deep flexion and full
extension. The knee and device should be free to move normally.
Motion of the device may be confirmed visually using fluoroscopy.
If motion of the knee or device has been compromised in an
unexpected manner as a result of the surgery, the device should be
removed. If excessive soft tissue binding is observed, widening of
the subcutaneous tunneled channel may be necessary.
[0185] Finally, the wounds are flushed thoroughly. Each wound is
closed layer by layer using physician's preferred technique and
suture preference and cover the wound with dressing.
[0186] With reference now to FIG. 46, in another approach, through
a second incision 212 on an opposite side of articulating members
at the interventional site, the bone is prepared for affixing a
second base component 215. Again, the surgeon's finger is used for
blunt dissection and along natural tissue planes, and the
periostium in the area is removed and displaced. Tissue is scraped
to the bone to expose a white, bleeding bone area while being
cautious not to disrupt the joint capsule. The refractor 188 can
again be used to stretch the tissue forming the opening during
implantation site preparation. While holding the incision open, one
or more possible second base components 215, here the tibia base
component, are placed against the prepared bone to identify a
desirable base-to-base component fit. As with all steps of the
procedure, remote viewing such as that provided by fluoroscopy is
employed to aid in proper sizing and fit.
[0187] Turning now to FIGS. 48-50, in one approach the second base
component 215 is removed from the site. A dummy link 216, including
first and second tapered ends 218, 220 is inserted through the
second incision 212 and is attached to a lower end of the first
base 190 (where the K-wire socket structure 208 has been removed).
The second base 215, the size and shape of which were previously
described, is subsequently inserted through the second incision 212
and placed against bone. Further, the second base component 215 is
connected to the dummy link 216 so as to get a sense of the
dimensions required for a proper link assembly to be attached to
both bases and to span a joint. This step can also help to confirm
or select the optimum placement of the second base 215 to bone.
[0188] In a related approach (See FIGS. 51-55), a fixed distance
link 222 having first and second ends 224, 226 can be utilized for
proper link selection and for confirming and selecting the optimum
second base position on a bone. Here, the second end 226 of the
fixed distance link 222 is releasably attached to a distal end of
an insertion and tunneling tool 228. A cover 230 having a tapered
profile is placed upon the first end portion of the fixed distance
link. A second cover 232 (See FIG. 54) can be additionally provided
to facilitate operation of the tunneling tool 228 within patient's
anatomy.
[0189] The insertion and tunneling tool 228 is placed within the
second incision 212 and is advanced toward the implanted first base
component 190 (See FIG. 54). The tool 228 forms a tunnel between
mounting locations without causing excessive tissue disruption. At
this time, the knee is flexed to ensure the tunnel is established
for all possible flexion/extension angles. Once there, the cover
230 is removed from the device and the first end 224 of the fixed
distance link 226 is attached to the first base 190. If a second
cover 232 is used, it is retracted to expose the fixed link 222.
The previously described clamp 206 can be used to accomplish the
connection between the components. The tunneling tool 228 is then
removed.
[0190] Whether using the dummy link 216 or the fixed distance link
222, steps are taken to connect the second base to bone (See FIGS.
56 and 57). As was done with the first base 190, a direct guide 234
can where desirable, be placed over the second base component 215.
While holding the incision 212 open, support K-wires 236 are
drilled through the guide 234, second base through holes 238 and
into bone. After removing the guide 234, compression screws or
other fasteners are used to fix the second base component 215 to
the bone. Verification of placement is confirmed through remote
imaging. Finally, the K-wires 236 are removed from the second base
component 215.
[0191] As shown in FIGS. 58 and 59, after removing structure
maintaining the position of the leg 175 in an extended position,
the lower portion of the leg is flexed so that it forms an angle
with the upper leg. The ends of the dummy or flexed length link
216, 222 are then disengaged from the bases 190, 215 and the link
is removed from the interventional site.
[0192] With reference now to FIGS. 60-66, one alternative or
complementary approach to sizing and selecting a link component is
described. A base location tool 240 including a pair of sliding
halves 242, 244 which form a hoop structure can be placed between
the first and second base components 190, 215. This tool 240 can be
used with bases that have been fixed to bone or prior to such
fixation. During use, a top side 246 resides on the outside of the
patient's skin. The top portion 246 can include indicia 247 for
identifying with certainty the space between the bases or the
length of a proper link. A bottom portion includes a pair of
oppositely located and spaced connection structure 248, 250. The
spaced connecting structure 248, 250 are sized and shaped to
releasably engage a respective one of the first and second bases
190, 215 and to permit a limited range of motion between the tool
and bases. It is also contemplated that the height of the base
locating tool can be modified for variations in patient skin and
tissue thicknesses.
[0193] Where the bases are yet to be fixed to bone, K-wires 248 can
be used to temporarily fix the bases in place (See FIG. 63).
Various sized and shaped bases 190, 215 can be used to achieve
proper fit. Next, the patient's anatomy, here the limbs forming the
knee, are flexed to record the maximum link extension required. A
check for bending of the components is made at this time both when
the anatomy is in its flexed (FIG. 64) and in its extended position
(FIG. 65). The bases are then affixed to bone (if not already done
so) and the base locator tool (and K-wires 248) is removed from the
site. In this way, proper position of the bases 190, 215 and/or
proper selection of a link is accomplished.
[0194] Turning now to FIGS. 67-73, once proper sizing of a link
component 250 has been made, an insertion and tunneling tool 228 is
employed to complete the assembly of a mechanical energy absorbing
device at the implantation site. The mechanical energy absorbing
device can be held in a longitudinally compressed condition by
wires or other delivery structures. Such a wire or other structure
can operate on the spring assembly of the device or can be attached
to other structure to accomplish the desired compression. Although
different embodiments can be used, here, the link assembly 250
includes first 252 and second 254 ends each with an articulatable
tapered post. The posts are each sized to fixedly engage one base
component 190, 215. The two part base/tapered post mounts provide a
method for good attachment of the base to the bone and a more
simple surgical technique for installing the link assembly. It also
allows the sheath and/or wear components of the link/mount assembly
to be removeable and/or replaceable without removing or replacing
the base components. It further allows the wear components of the
link/mount assembly and the base components to be different
materials. For example, the base components can be titanium or
titanium alloy which promote osteo-integration and the wear
components can be much harder materials such as cobalt chrome
(e.g., Biodur CCM Plus), ceramic, or other durable materials that
produce a minimal amount of particulate material or, if particulate
material is generated, the smallest size of particulate material.
The link assembly also includes energy absorbing and manipulating
structure 256 as well as an extendable sheath 260 extending between
a pair of spaced socket locks 262.
[0195] The tunneling tool 228 further includes a push rod 264, a
distal end of which releasably engages and stabilizes the link
assembly 250 through a connection with the second tapered post
structure 254. In use, the tunneling device 228 loaded with a link
assembly 250 is placed within the second incision 212 (an approach
through the first incision can also be employed with a link
assembly loaded in an opposite direction) and advanced as described
above previously toward the first base component 190. After
removing the distal cover 230, the first end 252 of the link
assembly is placed into complementary structure 266 of the base
component (See FIG. 70). To accomplish this connection, clamp 206
(See FIG. 27) or a similar tool is utilized. Additionally, a
plastic barrier can be temporarily inserted to keep the soft
tissues beneath the joint from interfering in connection of the
link assembly and sheath to the base component. An adjacent socket
lock 262 (See FIG. 71) is then manipulated to permit extending the
sheath (See FIG. 72) over a portion of the first base component
190. Similar steps are taken to connect and cover the second base
component 215 to the link assembly 250. Inspections are made to
ensure proper connections and the tunneling tool is then removed
from the site.
[0196] In an alternate approach, after creating a tunnel, the link
assembly can be placed in a sheath like sheath 232 of tunneling
tool 228 having a leading end closed by a suture (not shown). The
sheath with a leading suture can be inserted through the second
incision 212 and then through the space created between the
incision 190, 232, and thereafter, advanced toward the first
incision 190 by pulling on the lead suture. It is also contemplated
that one or more colored sutures can be employed for different
functions, such as pulling the sheath through the site and holding
a link assembly in a compressed state. In this way, the sheath acts
like a protective poncho facilitating the advancement of the link
assembly, being held in a longitudinally compressed state, through
the interventional space. Subsequently, cutting the suture can
release the link from the sheath so that the sheath can be removed
from the site. In the event multiple colored sutures are employed,
a second suture can be severed when desired to permit the link
device to assume a longitudinally expanded state.
[0197] Moreover, various tools can be employed to aid in
configuring a link assembly 250 between the bases 190, 215. As
shown in FIG. 74, a socket holder 280 including a ringlet 282 is
used to temporarily attach the link assembly 250 to a mount of the
femoral base 190. The ringlet can be pulled by hand or another tool
through a tunnel formed beneath the skin between the bases 190, 215
or alternatively simply used to temporarily attach the link to the
mount of the base. After temporarily attaching the link assembly
250 to the femoral base 190, the temporary socket holder is
replaced by a socket holder assembly 282 (See FIG. 75) which
includes clamping arms 284, 286 each having a terminal end which
engages opposing sides of a mount of a femoral base assembly. A
taper lock tool assembly 288 is configured about the clamping arms
284, 286. The taper lock tool assembly 288 includes an activation
arm 290 and a taper lock pusher block 292, each of which are guided
by a pair of spaced shafts 294. Actuation of the activation arm
results in the pusher block 292 accomplishing a locking engagement
of the link assembly 250 to the femoral base 190. In yet another
approach, temporary attachment of the link assembly 250 to the
femoral base 190 as well as the advancement of the link assembly
250 within a patient's skin can be achieved by using the socket
hook 296 shown in FIG. 76.
[0198] Turning now to FIGS. 77-79, another locking tool 300 is
illustrated. Here, the tool 300 includes a socket loader 302 having
a lead end configured to graspingly engage a mount 304 of a link
assembly 250. The socket loader 302 is sized and shaped to receive
a shaft 306 having a threaded portion for engagement with
complementary structures formed in the socket loader. A back end of
the shaft 306 includes a hex structure configured to receive a hex
drive component 308. In order to stabilize the tool 300, a counter
torque handle 310 sized to grasp the socket loader 302 is further
provided. In use, the socket holder 302 is placed into engagement
with a mount 304 and the hex drive 308 is turned to advance the
shaft distally. As the shaft 306 is advanced, it engages a recess
312 or other convenient structure of the base 190. From this anchor
position, the mount 304 is effectively drawn into locking
engagement with the base 190.
[0199] In an alternate approach, a locking tool 320 can further
include such structure intended to prevent damage to an implant
should a physician attempt to over tighten or use excessive force
to accomplish a locking engagement between implant components.
Thus, the tool 320 can embody a Belleville spring stack 322
configured to compress enough so that a shoulder on a hex 324 will
advance against a body 326 of the tool 320 and thus absorb the
excess forces rather than allow the same to be applied against the
implant. Accordingly, turning the hex 324 will advance a threaded
shaft 330 within the tool 320 to thereby move a top of a base/mount
engagement member 332 against a mount placed within a recess 334
sized for receiving the mount. Again, any excessive forces employed
to accomplish a locking engagement between implant components will
be blocked by the Belleville stack 327.
[0200] Once the physician is satisfied with the implantation, the
first 180 and second 212 incisions made at the interventional site
are then closed (See FIG. 81) and post-surgery clean-up is
performed. In instances where it is desirable to remove or replace
the link across two previously implanted base components two
incisions are made above each end of the absorber and tissue is
retracted to expose the absorber base coupling area and the sheath
is retracted or cut back. Using a removal tool the absorber is
decoupled from each base component without permanent deformation of
the base component and the absorber removed from within the tissue
tunnel. Another absorber unit may be coupled to the remaining bases
using previously described methods. In instances where it is
desirable to remove the base components in addition to the
absorber, the screws are removed and base components lifted from
the bone surface. In this scenario the device assembly including
absorber may be removed as a single unit.
[0201] In the event that it becomes necessary to remove the device
the following should be considered. To remove the kinematic
absorber unit, a removal instrument is inserted into the base
socket access port. The instrument is levered to press on locked
portion of the implant. Once this step is completed on both the
femoral and tibial bases, the absorber unit can be removed.
[0202] Stimulation of the interventional sites in combination with
implantation of a mechanical energy absorption device may
facilitate treating conditions affecting a body joint, such as
osteoarthritis, via a number of different mechanisms. Such
stimulation means can form an integral part of the mechanical
energy absorbing apparatus or can define separate structure.
[0203] In a first approach, electrical stimulation may block the
perception of pain associated with osteoarthritis. Electrical
stimulation of a joint affected by osteoarthritis, an
intraarticular joint space of the affected joint, one or more
peripheral nerves that innervate the affected joint, the spinal
cord, spinal segments supplying somatic sensation at the affected
joint, spinal segments supplying sympathetic control of the
affected joint, the nucleus gracilis, one or more cranial nerves,
one or more areas in the brain, the hypothalamus, the thalamus, the
motor cortex, and/or any other stimulation site may effectively
inhibit or relieve pain associated with osteoarthritis and help
with the efficacy of the implantation procedure.
[0204] Another contemplated approach involves the infusion of
drugs, chemicals, and/or other substances designed to or known
empirically to treat osteoarthritis. Infusing drugs, chemicals,
and/or other substances directly into the local area of an affected
joint or into nerves and/or arteries supplying the joint may allow
relatively high therapeutic doses. Thus, the infusion of drugs,
chemicals, and/or other substances into a joint affected by
osteoarthritis, an intraarticular joint space of the affected
joint, an artery supplying the affected joint, one or more
peripheral nerves that innervate the affected joint, the spinal
cord, spinal segments supplying somatic sensation at the affected
joint, spinal segments supplying sympathetic control of the
affected joint, the sympathetic ganglia, the nucleus gracilis, one
or more cranial nerves, one or more areas in the brain, the
hypothalamus, the thalamus, the motor cortex, and/or any other
stimulation site may also effectively facilitate treatment.
[0205] Stimulation can also involve proprioceptive pathways
supplying a joint with osteoarthritis. Stimulation of
proprioceptive pathways supplying a joint may improve patient
proprioception through the phenomenon of stochastic resonance.
Accordingly, stimulation of a joint affected by osteoarthritis, an
intraarticular joint space of the affected joint, one or more
peripheral nerves that innervate the affected joint, the spinal
cord, spinal segments supplying sympathetic control of the affected
joint, the nucleus gracilis, one or more cranial nerves, one or
more areas in the brain, the hypothalamus, the thalamus, the motor
cortex, and/or any other stimulation site may also lead to higher
incidence of efficacy.
[0206] Moreover, modulating the blood supply to a joint or direct
stimulation of the arteries supplying an affected joint may have
beneficial results. Therefore, stimulation of an artery supplying
the affected joint, one or more peripheral nerves that innervate
the affected joint, the spinal cord, spinal segments supplying
somatic sensation at the affected joint, spinal segments supplying
sympathetic control of the affected joint, the sympathetic ganglia,
the nucleus gracilis, one or more cranial nerves, and/or any other
stimulation site is contemplated. Alternatively, the blood flow
into a joint may be decreased by exciting sympathetic drive
responsible for generating vasoconstriction. Decreasing the blood
flow into a joint may reduce swelling in the affected joint and aid
in joint improvement.
[0207] Therefore, the present disclosure provides a number of ways
to treat body tissues and in particular, to implant absorb energy
or manipulate forces to reduce pain. Various aspects of the
disclosed approaches can be substituted for or used to complement
other of the disclosed approaches. Moreover, the present disclosure
can be used throughout the body but have clear applications to
articulating body structures such as joints.
[0208] Thus, it will be apparent from the foregoing that, while
particular forms of the invention have been illustrated and
described, various modifications can be made without parting from
the spirit and scope of the present disclosure.
* * * * *