Background: The distal soft tissue procedure is considered to be an effective surgical procedure to increase the correction in hallux valgus surgery. The goal of this study was to evaluate the efficacy of each single step of the lateral release in an experimental setup to assess which surgical steps are essential to correct hallux valgus deformity, which steps may be ineffective, and which steps may be risky.
Materials and methods: Three techniques of lateral release that differ in the sequence of surgical steps were evaluated in 15 fresh-frozen cadaver feet. After each step, an identical medial capsular reefing was simulated and the corrective effects on the metatarsophalangeal (MTP) angle, intermetatarsal (IM) angle, and sesamoid subluxation were assessed radiographically.
Results: Transection of the deep transverse metatarsal ligament and the attachment of the adductor hallucis muscle had virtually no corrective effect. Dissection of the lateral metatarsosesamoid suspensory ligament following incision of the lateral capsule and the lateral collateral ligament allowed correction of the MTP and IM angles as well as sesamoid subluxation in all three experimental settings. Dissection of the lateral short sesamophalangeal ligament and the plantar attachment of the articular capsule led to overcorrection and instability of the joint.
Conclusion: Transecting the lateral metatarsosesamoid suspensory ligament was the key to a successful lateral release in this model. Release of the deep transverse metatarsal ligament and the adductor hallucis muscle did not contribute to hallux valgus correction. The authors believe that the lateral short sesamophalangeal ligament and the plantar attachment of the articular capsule should be preserved to minimize the risk of possible joint instability.
Clinical relevance: The results of these study clarify contradictory findings in former clinical studies and should be considered in clinical practice.