Arthroscopic proximal carpal row replacement by semitendinosus and gracilis graft (CArpus Row Plasty Using the Semitendinosus: CARPUS procedure). An anatomical study of 16 cases

Abstract

Introduction: Post-traumatic lesions of the carpus (scapholunate rupture, scaphoid non-union) frequently evolve into disabling osteoarthritis (scapholunate advanced collapse or scaphoid non-union advanced collapse: SLAC or SNAC wrist). Proximal row carpectomy (PRC) is a reliable option but with poorer prognosis in case of osteoarthritis of the distal radius or capitate head. In such situations, radiocarpal arthrodesis may be necessary, sacrificing wrist motion. To circumvent this limitation, we propose a new procedure consisting in arthroscopic PRC and replacing the proximal row by tendon graft.

Methods: This was a study on 16 cadaver specimens. A scapholunate pin was introduced via an approach into the anatomical snuffbox and used as a guide for a cannulated drill bit (9mm) to create a tunnel through the proximal row. The arthroscope and a reamer were introduced into the tunnel via its radial and ulnar ends. PRC was performed under arthroscopic control. The gracilis and semitendinosus tendons were harvested and folded so as to obtain a graft with the same length and diameter as the proximal row. The graft was threaded through the radial approach and fixed to the capsule.

Results: Mean procedure time was 68min. There was no pre- to postoperative difference in joint motion or carpal height. On radiocinematography, the graft was stable between the radius and the second row of the carpus. The radial and ulnar sensory branches, median nerve and radial artery were intact at end of procedure.

Discussion: This technique could be a solution in SLAC or SNAC wrist with osteoarthritis of the capitate head or radial glenoid. It also conserves carpal height. Being arthroscopic, the procedure avoids the major edema observed after a dorsal approach of the carpus, and also ensures graft stability, since the radiocarpal ligaments are conserved. Harvesting from a second anatomical site and the in vivo fate of the transplant are two issues that need to be discussed.

Conclusion: This anatomical study paves the way for clinical experimentation.

Level of evidence: IV.

Keywords: Arthroscopy; Carpus; Plasty; Proximal row; Semitendinosus; Wrist.