- Discussion:
- lunate shaped spacer implant made of silicone, vitallium, acrylic, or rolled-tendon is inserted into the
resulting space to prevent migration of other carpal bones;
- due to the high rate of synovitis, most surgeons are now reluctant to use lunate implants;
- Technical Considerations:
- dorsal approach is used, the capsular structures are preserved, distal part of the 4th compartment
is incised, and EDC tendons are retracted ulnarly;
- lunate is removed piecemeal;
-
tendon spacer:
- roll the palmaris longus overr a small portion of the excised lunate (alternatively use the ECRB);
-
artificial spacer:
- use an absorbable suture through the prosthesis and into triquetrum, and also elevates a generous
portion of the dorsal retinaculum from the extensor tendons over the fourth and fifth radial canal;
- this is left attached to the radial border and is then sutured to dorsal surface of the scaphoid and the triquetrum;
- it is important to reconstruct the wrist ligaments & palmar joint capsule inorder to prevent
displacement of the implant;
- Hazards:
- silicone synovitis:
- although synovitis is seen less often w/ the lunate prosthesis as compared to the scaphoid implant,
the results are still unacceptably high;
- synovitis is more prevalent in young active patients;
- the longer the implant is left in place, the more wear debris is present;
- removal of the implant and debridement may not necessarily improve the silicone induced pain and
limitation of motion;
Kienbock's disease: the role of silicone replacement arthroplasty.
Use of a hand-carved silicone-rubber spacer for advanced Kienbock's disease.
The results of treatment of synovitis of the wrist induced by particles of silicone debris.
PM Murray and MB Wood.
JBJS Vol 80-A. No 3. March 1998. p 397.
