A NEW TECHNIQUE FOR THE THUMB CARPOMETACARCAL JOINT ARTHROPLASTY: FLEXOR CARPI RADIALIS SPARING HUMAN ALLOGRAFT

Abstract

PURPOSE: Trapezial excision with ligament reconstruction combined with tendon interposition has proven to be a highly effective technique for the treatment of OA of the CMC joint. We believe the same procedure is possible with use of modern orthobiologics.

Methods: 35 patients underwent surgical treatment for CMC arthritis with a new technique using Graft Jacket (Wright Med.) instead of FCR. Graft Jacket is an acellular human collagen (dermis) allograft. It is rapidly revascularized, repopulated with host cells and has high tensile strength.

Technique: The Graft Jacket was rehydrated and cut to create a 15cm strip. It was then placed around or sutured to the FCR (the anchor) and passed into the intramedullary cavity of the metacarpal as in the standard LRTI procedure. The remaining Graft Jacket is sutured together as an anchovy to fill the former trapezium gap, so that both suspension and interposition occurred. The mean age of the patients was 56 years and the median follow-up period was 1 year. All patients had marked pain and radiographic evidence of severe arthritis before surgery. Pain, grip and pinch (tip and key) strength, stability and range of motion were measured pre- and post-operatively. Pain was assessed on a VAS (Visual Analog Scale). The ability to perform ADLs (Activities of Daily Living) requiring use of the thumb and to return to work were analyzed as well. Following surgery all thumbs were immobilized in a static splint for 10 days and then were placed into a removable orthoplast splint for 4–6 weeks. Radiographic examination was performed in all patients at the 10th post-op day, and also at 2 and 6 months after surgery.

Results: Significants improvements were seen with grip strength (average 25lb) and tip (average 3.5lb) and key (average 4.5lb) pinch strength as well as palmar and radial abduction (average 25o). Pain was significantly reduced with an average of 6.0 on the VAS. There were no foreign body reactions or other infections in our series.

Conclusions: This study showed that excellent results can be achieved in strength, pain reduction, range of motion and ADLs with this new technique in which Graft Jacket was utilized instead of FCR in ligament reconstruction and interposition arthroplasty of the CMC joint. Our results indicate less morbidity than with use of FCR (swelling, ecchymosis or weakness) with excellent final outcomes.