- Discussion:
- lunate shaped spacer implant made of silicone, vitallium, acrylic, or rolled-tendon is inserted into theresulting 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.