Chronic scapholunate instability treated by scaphocapitate fusion: a midterm outcome perspective.

INTRODUCTION

Chronic scapholunate instability can lead to functional deficits and radiocarpal osteoarthritis. A number of procedures, namely scapho-trapezio-trapezoid (STT) fusion, scaphocapitate (SC) fusion or soft tissue reconstruction procedures, aim to improve function while protecting the wrist from osteoarthritis.

HYPOTHESIS

Define the role of scaphocapitate fusion in comparison to STT fusion and capsulodesis and ligament reconstruction.

MATERIAL AND METHODS

A clinical, radiographic and functional evaluation was performed on 31 SC fusion cases with an average follow-up of 5 years.

RESULTS

Range of motion was 41° in flexion and 39° in extension. Radial-ulnar deviation was 43°. Strength was 32.5 kgf (Jamar). The DASH was 27% and the PRWE was 25%. Fifty percent of the wrists were pain-free at rest. Ninety-four percent of patients were satisfied with the procedure. Seventy-eight percent of patients had returned to their occupation. Radiographic analysis revealed that consolidation was obtained at 10.1weeks. The postoperative radioscaphoid angle was 55° with good radioscaphoid congruence. There was no osteoarthritis in the radioscaphoid joint in 84% of the cases. The non-union rate was 13%.

DISCUSSION

These data are similar to the few series that exist. STT fusion leads the same clinical results, but it is technically more difficult and has a higher rate of complications. Capsulodesis and ligament reconstruction provide the same functional results as SC fusion, but with slightly less stiffening. However, these techniques do not seem to protect the wrist from arthritic degeneration at longer follow-up. SC fusion is superior to STT fusion for the treatment of chronic scapholunate instability. This is a pain-relieving intervention with good clinical results and preservation of scaphoid stability. As a component of the surgeon's armamentarium, it can be held in the same regard as capsulodesis and ligament reconstruction for cases of chronic scapholunate instability with a non-reducible scaphoid, or after failure of a soft tissue reconstruction procedure.

LEVEL OF EVIDENCE

Level 4, retrospective study.