Correction of clawed hallux deformity: Comparison of the Jones procedure and FHL transfer in a cadaver model

Background: A clawed hallux is defined as extension of the first metatarsophalangeal (MTP) joint combined with flexion of the interphalangeal JP) joint. Two operative procedures, the modified Jones procedure and flexor hallucis longus (FHL) transfer, are indicated for correction. The purpose of this study were to evaluate the overall effectiveness of these two procedures in correcting both the clawed hallux deformity and its mechanical consequences and to compare their effect on postoperative plantar pressures. Methods: The modified Jones procedure and FHL transfer were done on cadaver specimens that were tested before and after surgery in a specialized footloading frame. We quantified the angular correction of the MTP and the IP joints, as well as the plantar pressures under the head of the first metatarsal and the hallux. Results: Both surgeries were equally effective in correcting the angular deformity at the MTP and IP joints (p = 0.037 and 0.0020, respectively). A significant reduction in the plantar pressure (p = 0.015) beneath the first metatarsal was observed with both the modified Jones procedure and the FHL transfer. Overall, there was no significant difference between preoperative and postoperative pressures beneath the hallux (p = 0.5); however, for the FHL overpull group there was significantly less pressure beneath the hallux after surgery (p = 0.014). Conclusions: The two surgeries produced similar results, but the FHL transfer does not require fusion of the hallux, which is considered an undesirable comorbidity of the modified Jones procedure.