Flexor Digitorum Superficialis tendon transfer for a long-standing boutonniere deformity finger - a retrospective study of 11 cases.

INTRODUCTION: A long-standing boutonniere deformity is challenging to treat because of well-established complex pathophysiological changes in the extensor expansion mechanism. The role of ulnar slip flexor digitorum superficialis tendon transfer for central slip reconstruction in such chronic deformities is analyzed and correlated with the functional outcome.

HYPOTHESIS: Ulnar slip FDS tendon corrects the long-standing boutonniere deformity and replicates anatomical repair.

METHODS: We conducted a retrospective study between 2014 and 2016 and operated on 11 patients by FDS tendon transfer to the extensor expansion's central slip. We compared the preoperative and postoperative range of movements in the proximal interphalangeal joint, distal interphalangeal joint, Visual analogue score, and grip strength. Also, we statistically correlated various parameters and non-parameters affecting the functional outcomes.

RESULTS: The mean time interval between the injury and surgery was 39 months. The average follow-up of our study was 15.4 months. Ten of the 11 patients had good functional outcomes with statistically significant improvement in the movements and grip strength (p<0.05).

CONCLUSIONS: Ulnar slip FDS tendon transfer is effective for central slip reconstruction in a long-standing boutonniere deformity. Minimal degrees of proximal interphalangeal joint extension deficit is inevitable due to the chronicity and adaptive changes in the ligament-tendon-bone complex.

LEVEL OF EVIDENCE: IV; retrospective case study.