Improving the extensor lag and range of motion following free vascularized joint transfer to the proximal interphalangeal joint: Part 2. a clinical series

Background: Free vascularized joint transfer for reconstructing the posttraumatic proximal interphalangeal joint has enjoyed limited popularity because of the low range of motion typically achieved after transfer. One of the commonest complaints is the significant extensor lag. Part 2 of this two-part study is focused on the clinical outcomes following a more anatomical approach to extensor tendon reconstruction. Methods: Nine patients (eight male and one female), with a mean age of 31.7 years, underwent free vascularized joint transfer for posttraumatic proximal interphalangeal joint injuries using the second toe proximal interphalangeal joint. In Part 1, two arrangements of the central slip mechanism were found: type I with an attenuated and type II with a distinct central slip. An algorithm was constructed using this information: in a type I toe with sufficient recipient lateral bands, a centralization procedure was carried out; and when the lateral bands were insufficient, a modified Stack procedure was carried out. In type II toe joints, a tight repair of the corresponding extensor tendons was performed. Results: Four patients underwent centralization procedures, two underwent a modified Stack procedure, and three underwent tight extensor repair. At 23.4 months, the average extensor lag was 18.3 degrees. A total range of motion of 53.9 degrees (mean flexion, 72.2 degrees) was achieved that approximated 81.1 percent of the pretransfer passive range of motion at the toe proximal interphalangeal joint. Conclusion: This preliminary result demonstrates that much improved range of motion can be achieved by reducing the extensor lag using an anatomical reconstruction that takes into account the recipient finger and toe joint anatomy. Clinical Question/Level of Evidence: Therapeutic, IV.