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Joint
fusion results in permanent loss of
motion at the affected joint. Soft
tissue arthroplasty requires replacement
of the joint space with interpositional
soft tissue. Normal anatomic
features of a joint are not restored and
this can lead to instability and
deformity. Silastic arthroplasty,
also known as Swanson arthroplasty, is
performed with a silastic (silicone) one
piece joint. The joint contains a
central area with reduced bulk that acts
as a hinge. It requires adequate
bone stock and soft tissue, with good
muscle tendon balance. Two piece
arthroplasty is also known as surface
replacement arthroplasty. It was
developed by Linscheid in an attempt to
recreate normal joint surface
anatomy. Rectangular stems on the
implants minimize rotation, while the
bicondylar design aids in lateral
stability.
Complications
of joint replacement include
Secondary
surgery with extensor of flexor
tenolysis may be required.
Vascularized
joint transplantation provides a living
joint, using the second to PIP or MP
joint as a donor. Because the
tissue is vascularized, this type of
joint replacement can last a lifetime,
and is not prone to mechanical failure
like a silicone or metal joint. It
can also provide soft tissue and bone
where those have been lost by injury or
infection. Tendon can also be
brought with the joint as a single unit.
Clinical
Example Vascularized Joint and Two Piece
Arthroplasty
 This
patient suffered a saw injury to the
right hand with near amputation of the
index finger including loss of the
extensor tendon, pip joint and middle
phalanx. The long and ring fingers
suffered dorsal extensor tendon injuries
and pip joint destruction.
 The
long and ring fingers were placed in a
fixed extension position with k-wires
and the extensor tendons were
repaired. The index finger was
placed in an external fixation system to
hold the finger out to length, since the
middle phalanx was lost in the
injury.
 The
index finger bone loss in pictured in
the radiograph. The external
fixator holds the proximal and distal
phalanx out to length and in good
position.
 Preoperative
angiography of the hand revealed good
digital artery perfusion to the index
finger with a patent arch supplied by
relatively equal ulnar and radial
arteries. The radial digital
artery could be used for inflow in the
transplant since the ulnar digital
vessel supplied good flow to the tip of
the finger.
 A
vascularized joint transplant was used
to reconstruct the PIP joint of the
index finger and to replace the lost
middle phalanx. The toe is
pictured harvested with the volar
pedicle and dorsal venous system visible
against blue backgrounds.
The toe is
illustrated above, showing the arterial
and venous system, as well as the flexor
and extensor tendon. Further
surgical dissection was then performed
to isolate the PIP joint with middle
phalanx with a portion of proximal
phalanx and extensor tendon and flexor
tendon.
After
further dissection, the vascularized toe
joint is illustrated above. The
extensor tendon system was kept to
reconstruct the system that was lost in
the injury. The flexor tendon was
used to replace the mutilated flexor of
the index. A skin paddle is left
dorsally to provide soft tissue coverage
for tissue that was lost and developed
scar contracture while in the external
fixator.
The hand is
shown over one year after the joint
transplant and two piece joint
replacement in the long and ring
finger. Lateral and volar views
reveal good extension and flexion.
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