ARTHROSCOPIC DEBRIDEMENT AND CLOSED PINNING FOR LATE PRESENTING DYNAMIC SCAPHOLUNATE INSTABILITY.

Abstract

Arthroscopic debridement and pinning is not considered to be effective in dynamic scapholunate (SL) instability treated more than three months post injury; open procedures (capsulodesis, tenondesis, SL ligament reconstruction, intercarpal fusions) are preferred for these patients. The best procedure for this problem is yet to be determined. A restrospective review of the senior author’s records produced thirteen patients with late presenting dynamic SL instability who were unwilling to undergo an open procedure and were treated initially with aggressive arthroscopic debridement and pinning. The mid-term results of this approach are presented.

Eleven of the initial thirteen patients were available for follow-up. Their mean age was 36 years (range 23–50) and the mean time elapsed from injury was 7 months (range 4.5–10). The diagnosis of dynamic SL instability was based on a positive Watson’s test, SL gapping on grip view radiographs and arthroscopic findings of a Geissler type III (in 5 patients) or type IV (in 6 patients) SL tear. The SL angle was under 550 in all patients. The procedure included aggressive arthroscopic debridement of the torn portion of the SL ligament to bleeding bone in an effort to induce scar formation in the SL interval. The SL interval was subsequently reduced and pinned (with 2 pins through the SL and one pin in the scaphocapitate joint) under fluoroscopy. The pins were removed at a mean of 9.6 weeks (range 8–14).

The mean follow-up was 36 months (range 12–76). Three patients were re-operated at 9, 10 and 11 months after the initial procedure. Re-operations included a dorsal capsulodesis, a four-corner fusion and a wrist arthrodesis. The eight remaining patients achieved two excellent, four good, one fair and one poor result with the Mayo wrist score. Patients diagnosed with Geissler III tears were found to be younger and achieved better final wrist score (mean 86 points versus 76 points in patients with Geissler IV tears). Two pin track infections were treated conservatively.

Late (more than three months post injury) arthroscopic debridement and pinning was found to be only moderately successful for dynamic SL instability (6 out of 11 patients achieved a good or excellent result without re-operation). This approach, however, does not preclude subsequent open surgery. It is best suited for patients with Geissler type III tears (not a gross drive through sign) who are unwilling to undergo an extensive open procedure provided they understand the risks and benefits of this approach.