Surgical reduction and ligament reconstruction for chronic dorsal dislocation of the lesser metatarsophalangeal joint associated with hallux valgus.

Background: Hallux valgus (HV) is occasionally associated with chronic dislocation of the lesser metatarsophalangeal (MTP) joints. We have developed a novel surgical procedure to treat dislocation of the lesser MTP joints. This study aimed to describe our procedure and investigate the outcomes of surgical intervention in the treatment of HV with dislocation of the lesser MTP joints.
Methods: Twenty-three patients (27 feet, average age: 63.6 years, average follow-up: 49.5 months; a minimum follow-up of 24 months) underwent surgical intervention for HV and dislocation of the lesser MTP joints. Twenty-three feet had dislocation (10 feet) or subluxation (13 feet) of the second MTP joint, whereas 4 feet had dislocation of the second and third MTP joints. The surgical procedure included a distal soft-tissue procedure combined with proximal osteotomy for correction of the HV, and reconstruction of the collateral ligaments (CL) following open reduction with complete release of the capsule and the CL at the metatarsal head for dislocation of the lesser MTP joints. Outcomes were assessed using the Japanese Society for Surgery of the Foot (JSSF) scale and radiological examinations.
Results: The JSSF score improved significantly from an average of 49.7 points preoperatively to 93.1 points postoperatively. The average HV angle and intermetatarsal angle decreased significantly from 44.6° and 18.1° preoperatively to 7.9° and 6.0° postoperatively, respectively. The average extension and flexion of the second MTP joint was 53.1° and 13.8° at the most recent follow-up, respectively. Postoperatively, no feet had dislocation of the second or third MTP joint, three had subluxation of the second MTP joint, and one had subluxation of the third MTP joint. Osteoarthritis of the lesser MTP joint had developed in two feet (7.4 %) at the time of the most recent follow-up.
Conclusion: Our surgical procedure achieved significant correction of HV, a low rate of postoperative re-dislocation of the lesser MTP joints, and significant improvement of pain and function for symptomatic moderate-to-severe HV with dislocation of the lesser MTP joints.
Level of Evidence: Level IV, retrospective case series.