The Impact of Transferred Vascularized Toe Joint Length on Motion Arc of Reconstructed Finger Proximal Interphalangeal Joint

Abstract

Objective: Vascularized toe joint transfer for finger proximal interphalangeal joint (PIPJ) reconstruction is a well-described technique in the literature. However, the reconstructed PIPJ is known to have issues with suboptimal range of motion and extension lag. One of the reasons for this problem is the length of the intercalated bony segment. There is a lack of evidence and consensus regarding the optimal length of the intercalated segment. This study hence was performed to determine the impact of the intercalated segment length on the subsequent passive arc of motion (AOM) and extension lag of the reconstructed PIPJ. Materials and Methods: We harvested the intercalated joint graft (the toe PIPJ along with its associated extensor tendons) from the lesser toes and transferred it to the finger of cadavers. A predetermined constant PIPJ defect size of 2 cm was created on the finger. By insetting 3 different lengths of the intercalated segment to the finger PIPJ, we investigated the effect of shortened (1.5 cm), exact (2.0 cm), or lengthened (2.5 cm) intercalated segment lengths on the AOM and extension lag of the reconstructed PIPJ. Results: The average AOM of finger PIPJ was 81.0° ± 19.1° and that of the toe PIPJ was 53.6° ± 16.1°. In the group with longer intercalated segment, the average AOM was 29.9° ± 10.5° with an extension lag of 32° ± 11.7°. In the group with equal intercalated segment length, the average AOM was 49.1° ± 11.5° with an extension lag of 15.4° ± 10.6°. In the group with shorter intercalated segment, the average AOM was 70.9° ± 12.6° with an extension lag of 8.4° ± 8.9°. Conclusions: From our study, shortening the intercalated segment may provide the most reduction in the extension lag of the reconstructed PIPJ. Future studies could involve further refinement of the amount of length to be shortened. This would probably lie between 0 to 5 mm.