Surgical Procedures Based on the Arthrographic Findings of the Fifth MTP Joint With Proximal Phalanx Duplication in Postaxial Polydactyly of the Foot

Radiographic findings in several atypical cases of postaxial polydactyly of the foot do not provide sufficient information to assess the cartilaginous structures or duplicated digit connections at the MTP joint. The purpose of this study was to demonstrate the surgical procedures using arthrography for the cartilaginous structures of the MTP joint in postaxial polydactyly of the foot. We performed arthrography in 7 feet of 7 patients with postaxial polydactyly of the foot in which duplication of the proximal phalanx was observed at the fifth MTP joint on the basis of radiographic evaluation. The average age at surgery was 13.5 months and average duration of postsurgical follow-up was 36 months. Individual surgical procedures were confirmed or modified during the operation by reference to the arthrographic findings. Radiographic and arthrographic findings were assessed in relation to the findings from direct observation of the cartilaginous structures at surgery. Postoperative malalignment, functional disturbance and pain in the reconstructed toe were evaluated. The arthrographic findings provided different forms of cartilaginous structures that could be categorized in 4 types, and reflected the cartilaginous connection visualized at surgery that could not be detected on radiographs in each case. No cases revealed any deformities, functional disturbance, or pain in the reconstructed toe after surgery. The parents’ evaluation in each case was “very satisfied” or “satisfied.” The arthrographic findings provided additional information regarding variations in the cartilaginous structures of the fifth MTP joint and for determining individual surgical procedure for postaxial polydactyly of the foot.