Chronic instability of the thumb metacarpo-phalangeal joint: Seven-year outcomes of three surgical techniques.

BACKGROUND: Severe sprain of the thumb metacarpo-phalangeal joint (TMCPJ) is a common injury whose functional outcome is good when repair is performed at the acute stage. The diagnosis is often missed, however, leading to chronic instability. The optimal treatment of chronic TMCPJ instability is controversial. The objective of this study was to compare the clinical outcomes of the three main surgical techniques used to treat chronic TMCPJ instability.

HYPOTHESIS: Arthrodesis is the best surgical option when ligament repair is not feasible.

MATERIAL AND METHODS: This single-centre retrospective study included all patients managed surgically between 2000 and 2012 for chronic post-traumatic TMCPJ instability using any of the three following techniques: primary repair, ligament reconstruction, and arthrodesis. Subjective and objective outcomes and complication rates at last follow-up were compared across these three techniques.

RESULTS: Of 67 included patients, 55 were re-evaluated, after a mean follow-up of 84 months (range: 24-164 months). Among them, 48 (87.3%) were satisfied or very satisfied with the outcome. Pain relief was significantly better in the arthrodesis group. Mean Quick-DASH scores were 17.4 (range: 0.0-89.5) with primary repair, 25.7 (range: 0.0-58.3) with ligament reconstruction, and 17.8 (range: 0.0-50.0) with arthrodesis. Mean pinch-test strength compared to the normal side was 89% with primary repair, 84% with ligament reconstruction, and 94% with arthrodesis. In the ligament reconstruction group, 6 of the 10 patients had instability at last follow-up and the proportion of patients describing themselves as fully recovered was significantly smaller than in the other groups. Four failures were recorded at last follow-up.

CONCLUSION: Surgery to treat chronic TMCPJ instability produces good outcomes. Primary repair deserves preference whenever possible. In contrast to previous reports, outcomes after ligament reconstruction were not better compared to arthrodesis.

LEVEL OF EVIDENCE: IV, retrospective study.