[Effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint].

Objective: To investigate the effects of tibial second toe free flap bridged with blood flow and nerve in the treatment of severe flexion contracture of the proximal interphalangeal joint. Methods: A retrospective observational study was conducted. From March 2013 to October 2019, 9 patients with severe flexion contracture (type Ⅲ) of the proximal interphalangeal joint after trauma operation, conforming to the inclusion criteria, were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 5 males and 4 females, aged from 17 to 62 years. After the contracture tissue affecting the extension of the proximal interphalangeal joint was cut off, and the scar tissue was resected, the size of the volar wound near the proximal interphalangeal joint in extended position was 2.0 cm×1.0 cm-2.5 cm×1.5 cm, with the length of proper digital artery and nerve defect being 1.0-1.5 cm. A free flap of the same size as the wound was cut from the tibial side of the second toe and transplanted to repair the wound, and the defective proper digital artery and nerve was repaired by bridging with the tibial proper plantar digital artery and nerve of about 1.5 cm in length. The full-thickness skin graft was taken from the proximal tibial side of the lower leg to repair the wound at flap donor site. The wound at skin graft donor site was sutured directly. The survival of flap and skin graft was observed after operation. The patients were followed up, and at the last follow-up, the recovery of the affected finger and the second toe, including the donor and recipient areas were observed, the two-point discrimination distances of the flap repaired site and the pulp of the affected finger were observed and measured at the same time, the blood flow patency of bridged vessel of the affected finger was examined by Allen test, and the function of the proximal interphalangeal joint of the affected finger was evaluated according to Chinese Medical Association's standard for the range of motion of proximal interphalangeal joint. Results: The flaps and skin grafts survived smoothly after operation. The follow-up after operation lasted for 5 to 22 months, with a mean of 10 months. At the last follow-up, the flap repaired site had good shape, good color and texture, with the two-point discrimination distance being 9-12 mm, and the two-point discrimination distance of the pulp of the affected finger was 6-10 mm; the Allen test results of the affected fingers were all negative (i.e., the bridged vessels had good blood flow patency), with no recurrence of flexion contracture, and the function of the proximal interphalangeal joint was evaluated as excellent; the skin graft area of the second toe was not ruptured but was a little pigmented, and the flexion and extension activities of toe were good. Conclusions: The tibial second toe free flap bridged with blood flow and nerve has reliable therapeutic effect in the treatment of severe flexion contracture of the proximal interphalangeal joint, and the color and texture of the flap repaired area are good. Bridging to repair the severely contracted proper digital artery and nerve is beneficial to improve the blood supply of the finger body and rebuild the sensation.