Reconstruction of the condyles of the proximal phalanx with osteochondral grafts from the ulnar base of the little finger metacarpal.

Purpose: Traumatic defects of the condyles of the proximal phalanx (P1) are challenging injuries. Use of osteochondral grafts from the hamate had been described for defects of the base of the middle phalanx. Extending this concept, the purposes of this study were to see whether an osteochondral graft from the base of the little finger metacarpal was anatomically feasible to reconstruct a condyle of P1, and to determine whether the reconstructions performed were clinically successful.

Methods: We measured the radius of curvature of the base of M5 and the condyles of P1 of the 4 fingers in 15 dry hand skeletons and compared them. We retrospectively reviewed 15 patients with traumatic loss of one condyle of P1. In addition, 16 osteochondral grafts from the ulnar side of the base of the M5 were harvested, tailored to reconstruct the defect, and fixed with screws. Average follow-up was 4.8 years (range, 1-7.5 y). We measured the active arc of motion of the proximal interphalangeal joint.

Results: The radius of curvature of the base of M5 was 5.6 mm (range, 4.2-7.2 mm), whereas the radiuses of curvature of the condyles of P1 of the index and long fingers were 4 mm, and those of the ring and little fingers were 3.8 mm. The radius of curvature of the base of the M5 was 40% and 47% larger than that of the P1 condyles of the index-long and ring-little fingers, respectively. The active arc of motion of the proximal interphalangeal joint in the clinical cases averaged 49 degrees (range, 20 degrees to 100 degrees ). There was partial graft resorption without pain, instability, or notable loss of arc of motion. There was no severe donor-site morbidity.

Conclusions: The base of the M5 is a suitable donor site of osteochondral grafts for the condyles of P1 based on anatomical grounds. The series reported, though short and nonhomogeneous, suggests that the medium-term results of this technique are acceptable.

Type Of Study/level Of Evidence: Therapeutic IV.