U.S. patent number 3,924,276 [Application Number 05/550,173] was granted by the patent office on 1975-12-09 for surgically implantable trapezium prosthesis and method of reconstructing the thumb carpometacarpal joint.
Invention is credited to Richard E. Eaton.
United States Patent |
3,924,276 |
Eaton |
December 9, 1975 |
Surgically implantable trapezium prosthesis and method of
reconstructing the thumb carpometacarpal joint
Abstract
A prosthesis for the trapezium of the thumb carpometacarpal
joint comprising an integral elastomeric member configured to
include a generally cylindrical portion, having extending from one
end thereof an elongated, longitudinally extending tapered portion
adapted to be embedded into a reamed out-channel in the thumb
metacarpal bone, while the opposite end of said cylindrical portion
is slightly concave to conform to the navicular bone, and wherein
said cylindrical portion includes a transverse aperture. In the
subject method following the step of implanting the tapered
projection of the subject prosthesis in the thumb metacarpal bone,
the axis of the aperture is aligned perpendicular to the plane of
the thumb, and a segment of the flexor carpi radialis tendon is
then passed over the cylindrical portion of said prosthesis and
down through the aperture, and then fixed to the main portion of
said tendon, thereby forming a reinforced structure to inhibit
dislocation of the prosthesis.
Inventors: |
Eaton; Richard E. (Pelham
Manor, NY) |
Family
ID: |
24196046 |
Appl.
No.: |
05/550,173 |
Filed: |
February 18, 1975 |
Current U.S.
Class: |
623/21.15 |
Current CPC
Class: |
A61F
2/4241 (20130101); A61F 2/4261 (20130101); A61F
2002/30299 (20130101); A61F 2002/30224 (20130101); A61F
2/08 (20130101); A61F 2230/0069 (20130101); A61F
2002/4258 (20130101); A61F 2002/30878 (20130101); A61F
2/0811 (20130101); A61F 2002/4276 (20130101); A61F
2002/30069 (20130101); A61F 2230/0093 (20130101); A61F
2002/30772 (20130101) |
Current International
Class: |
A61F
2/42 (20060101); A61F 2/00 (20060101); A61F
2/08 (20060101); A61F 2/30 (20060101); A61F
001/24 () |
Field of
Search: |
;3/1.9-1.913,1
;128/92C,92CA |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Silicone Rubber Implants for Replacement of Arthritic or Destroyed
Joints in the Hand," by Alfred B. Swanson, Surgical Clinics of
North America, Vol. 48, No. 5, Oct. 1968, pp. 1113-1127..
|
Primary Examiner: Frinks; Ronald L.
Attorney, Agent or Firm: Casella, Esq.; Anthony J.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A prosthesis for the trapezium of the thumb metacarpal joint
comprising an integral, elastomeric member configured to include a
generally cylindrical portion, having extending from one end
thereof an elongated, longitudinally extending tapered portion, and
wherein said cylindrical portion includes a transverse aperture
extending through the longitudinal axis of said prosthesis.
2. A prosthesis for the trapezium of the thumb metacarpal joint as
in claim 1 wherein said elongated, longitudinally extending tapered
portion is annular in cross section and includes a blunt end.
3. A prosthesis for the trapezium of the thumb metacarpal joint as
in claim 1 wherein the opposite end of said cylindrical portion is
slightly concave to conform to the end of the navicular bone.
4. A prosthesis for the trapezium of the thumb metacarpal joint as
in claim 1 wherein said elastomeric is silicone rubber.
5. A method of reconstructing the metacarpal joint of a thumb by
surgically implanting an improved trapezium prosthesis having a
cylindrical portion to which is integrally connected an elongated
tapered portion, and with an aperture extending transversely
through said cylindrical portion, comprising the steps of:
a. removing the diseased trapezium;
b. reaming the medullary canal of the thumb metacarpal bone to fit
the elongated tapered portion of said prosthesis;
c. inserting the prosthesis elongated tapered portion into said
medullary canal, and aligning the aperture in the cylindrical
portion of the prosthesis to extend perpendicular to the plane of
the thumb nail;
d. stripping away approximately a 6 centimeter portion of the
flexor carpi radialis tendon, leaving the distal attachment intact
adjacent the prosthesis;
e. extending the split tendon around the surface of the prosthesis
then passing the same through the aperture in the prosthesis to a
point intersecting the remaining flexor radialis at the palm side
of the hand, and suturing said split tendon to the flexor radialis
tendon;
f. weaving the remaining free end of the tendon in the vicinity of
the prosthesis to form a new capsule securing the prosthesis in
place.
Description
Freedom from pain is essential for normal thumb function. Although
the carpometacarpal joint of the thumb is described as a saddle
joint, it is actually formed by apposed saddles, one astride the
other, each one's longitudinal axis perpendicular to the other.
Such a relationship creates a joint where two primary planes of
motion, flexion-extension and adduction-abduction, are
perpendicular to one another. With rotatory movement such as
opposition and circumduction, the surfaces are twisted into a less
congruous relationship, causing tightening of the joint capsule and
thereby increasing joint stability, provided all ligaments are
competent.
Idiopathic hypermobility of the thumb basal joint is not uncommon,
particularly in women, and would seem to be a major factor in
producing the arthrosis which so frequently afflicts this joint.
Trauma, acute or recurrent, causing partial tears or stretching of
the ligaments, likewise will produce varying degrees of
hypermobility. Undetected articular damage may also accompany such
trauma, thereby compounding the pathological process. When painful
hypermobility is present, restoration of ligament stability will
not only relieve the pain and stabilize the joint, but, when done
prior to the onset of articular damage, may prevent or at least
retard subsequent joint degeneration. A new ligament reconstruction
procedure for painful, unstable thumb carpometacarpal joint is
presented in an article entitled "Ligament Reconstruction for the
Painful Carpometacarpal Joint," by applicant, Dr. Richard Eaton,
and Dr. J. William Littler, which appears in the Journal of Bone
and Joint Surgery, Vol. 55-A, No. 8, pp. 1655-1666, December,
1973.
For more advanced arthrosis, ligament reconstruction is not
sufficient. Advanced arthrosis is generally recognized by the
obvious dorsal subluxation of the metacarpal base. As the base of
the thumb metacarpal subluxates dorsally, there is a reciprocal
flexion-abduction of the metacarpal shaft, and frequently
flexion-adduction contracture of the entire thumb ray. Carried to
the extreme deformity, the metacarpophalangeal joint compensates
for the metacarpal flexion-adduction position by hyperextending and
the joint may become fixed in this hyperextended position. These
sequential compensation deformities must be recognized and
corrected at the same time as reconstruction of the basal joint is
carried out.
Heretofore, deformities of the carpometacarpal joint have been
undertaken utilizing a trapezium prosthesis, and implanting the
prosthesis following removal of the diseased trapezium bone. One
known prosthesis comprises an integral elastomeric member,
preferably of a flexible silicone material, having a cylindrical
base portion from one end of which extends a triangular shaped
projection adapted to be imbedded into the reamed-out channel in
the thumb metacarpal bone. In view of the very slippery, low
coefficient surface of the material of the prosthesis, and the fact
that the elastomeric material of the prosthesis is difficult to
handle and will not hold a stitch, when implanted, the prior art
prosthesis has a tendency to slip out of place in that the opposite
end of the cylindrical portion of the prosthesis merely rests
against the adjacent navicular. Furthermore, when implanted, the
amount of force applied by the patient, in a pinching direction of
the hand, must be limited in order to prevent inadvertent popping
out of the prior art prosthesis. Still further, in order to insure
as close a fit as possible, in order to minimize slipping out of
position of the prosthesis, several different sizes of prosthesis
must be manufactured, and by trial and error implanted into the
patient's hand.
Another form of known prosthesis or trapezium prosthesis is of the
general shape of the prior art device described above with the
addition of several elastomeric tails or extending elements which
are looped around a structure of the palmer aspect of the hand in
an attempt to keep the prosthesis from dislocating dorsally. As is
readily apparent, considering the type of material which must be
employed for an implantable prosthesis, the tails or extending
elements are extremely fragile, and tend to wear and break thereby
losing the fixation sought to be obtained. In addition, it is
difficult to firmly secure the elastomeric tails to the hand
structure, thereby resulting in the patient having to limit the use
of his hand with reference to the application of hand grip
forces.
Accordingly, it is the object of the subject invention to provide a
new and improved surgically implantable trapezium prosthesis, as
well as a new and improved method of reconstructing the thumb
metacarpal joint. More particularly, it is an object to provide a
new and improved prosthesis and method which will provide the
patient with, as close as possible, his original strength and
flexibility of the carpometacarpal joint.
Specific details relative to the subject invention will be fully
described below with reference to the accompanying drawings in
which:
FIG. 1 is a perspective view of the new and improved surgically
implantable trapezium prosthesis according to the subject
invention;
FIG. 2 is a side view of said prosthesis;
FIG. 3 is a top view of a thumb and the surgically implanted
trapezium prosthesis according to the subject invention; and
FIG. 4 schematically illustrates the completed surgically implanted
trapezium prosthesis as firmly fixed in place by the use of a
portion of the patient's tendon.
Referring to FIGS. 1 and 2, the trapezium prosthesis of the subject
invention is generally designated by the numeral 10 and comprises
an integral elastomeric member, preferably a silastic material such
as silicone rubber, and which is inherently flexible and
physiologically inert. The prosthesis 10 includes a generally
cylindrical portion 12 having end faces 14 and 16, and integrally
formed and projecting from the end face 14 is an elongated,
longitudinally extended tapered portion 18. The end 19 of the
tapered portion 18 is blunted, and the tapered portion has a
generally annular cross-section. The opposite end face 16 of
cylindrical portion 12 is slightly concave in order to more
effectively cooperate with the navicular or scaphoid bone 40 (see
FIGS. 3 and 4), as will be more particularly described
hereinafter.
Extending transverse to the longitudinal axis of the prosthesis 10,
and more particularly radially through the cylindrical portion 12
is an aperture 20. The diameter of the aperture 20 is suitably
dimensioned relative to the size of the cylindrical portion 12 to
prevent tearing of the prosthesis 10, and furthermore is large
enough to fully accommodate the portion of the tendon which is to
be inserted therethrough, as described below.
FIGS. 3 and 4 illustrate steps in the process of applicant's
invention. As shown in FIG. 3, in the subject process of
reconstructing the thumb carpometacarpal joint 34 following the
surgical removal of the diseased trapezium, the surgeon then
performs the step of hollowing out the lining of the marrow cavity
of the metacarpal bone 36 utilizing conventional techniques and
conventional apparatus such as an electric reaming device in order
to define any elongated cavity 38 in the metacarpal bone 36. The
prosthesis 10, and more particularly the elongated extended portion
18 is inserted into the cavity 38, and the prosthesis is rotated so
that the longitudinal axis of the aperture 20 extends orthogonal to
the plane of the patient's thumb nail 32 of the thumb 30. The
alignment of the aperture is important in reconstructing the
metacarpal joint 34, as will be more fully described hereinafter.
The base or end face 16 of the prosthesis 10 should fit in good
contact circumferentially with the cortex or outer portion of the
thumb metacarpal 36 so that it has even pressure around the entire
contact surface. Likewise the opposite end face 16, which is
slightly concave, should fit in good firm contact with the
navicular or scaphoid 40. The next step in the subject process is
to obtain a strip of adjacent tendon for which is suggested the use
of the flexor carpi radialis tendon. Through conventional
technique, two incisions are made above the wrist, and the flexor
carpi radialis tendon 50 is partially cut across its width as at
52, and stripped along the longitudinal line 54 to obtain a strip
56 of about 6 centimeters in length. This segment 56 is tunneled
under the skin to emerge at the wrist in the vicinity of the
metacarpal joint, after which the free end of the tendon strip 56
is directed around the surface of the prosthesis 10 (see FIG. 4)
and then penetrated through the residual capsule attached to the
metacarpal 36 at a point which again is perpendicular to the plane
of the thumb nail 32, and then the tendon strip 56 is passed
through the aperture or channel 20 in the prosthesis 10, and then
to the remaining flexor radialis, as at point 58, at the palm side
of the new reconstructed joint. The strip 56 is fixed, such as by
means of two switches, to the flexor radialis tendon 50 on the
dorsal side of the hand, at the point where it enters the
prosthesis on the dorsal of the wrist, and then likewise the
prosthesis is pulled into place by pulling on the ligament, thereby
seating it into its socket, and then a second suture is placed
between this new ligament and the flexor radialis 50. The free tail
60 usually represents about 4 centimeters, and this free tail is
then interwoven across and around the prosthesis to form a new
capsule for the metacarpal joint. The use of a tendon as a building
material to weave a new capsule provides an extremely strong and
durable construction, since it is thicker than the natural capsule,
and of course, since it is the patient's own tissue it cannot and
won't be rejected. It will adhere to any normal tissue, and it will
not adhere to the elastomeric material of the prosthesis 10. Of
course, the tendon does not have to adhere to the prosthesis since
it passes directly through the prosthesis and therefore becomes
incorporated in the prosthesis. As indicated before, suturing of a
prosthesis is not possible because of the nature of the substance,
and secondly because the prosthesis would be much weaker than using
the thick 3 or 4 millimeter tendon which is passed through the
center of the prosthesis, as in applicant's process. Furthermore,
the tendon cannot tear the prosthesis.
The resulting reconstructed metacarpal joint is significantly
stronger and more durable than prior art reconstructed joints using
conventional prosthesis. The alignment of the aperture 20 of the
prosthesis assures that the passing of the tendon therethrough will
hold the prosthesis in the socket that was created by the removal
of the diseased trapezium, and provide the necessary reconstructed
metacarpal joint to enable the patient to resume his normal
activities without fear of slipping of the prosthesis or movement
thereof. According to the inventor's experimentation, it has been
found that with prior art prosthesis, the patient's grip strength
is only restored to the extent of 8 to 10 pounds, and certainly not
in excess of 15 pounds, whereas the normal joint strength of a
patient is in the area of 40 to 80 pounds grip strength. Utilizing
applicant's prosthesis and applicant's process, such grip strengths
on the order of 40 to 80 pounds may be restored in the event of a
diseased trapezium, when using applicant's device and process.
While the prosthetic device was described with reference to the
drawings as being made of silicone rubber it will be realized that
other inherently flexible, clinically inert materials having
sufficient strength may also be used.
To those skilled in the art to which this invention relates, many
changes in construction and widely different embodiments and
applications of the subject process and device will suggest
themselves without departing from the spirit and scope of the
invention. The disclosures and descriptions herein are purely
illustrative and are not intended to be in any sense limiting.
* * * * *