Efficacy of first metatarsophalangeal joint lateral release in hallux valgus surgery

Abstract

Lateral release of the sesamoid ligament complex is one of the key step to the surgical treatment of hallux valgus. Although numerous techniques are available to perform this procedure, there is no accepted consensus on the method of choice. The goal of this study was to evaluate the efficacy of sequential release of lateral soft tissue structures for correction of hallux valgus deformity. This study included 40 patients, mean age 50.9 years old (±17.4), with 49 hallux valgus deformities from mechanical causes. The first metatarsophalangeal angle (M1P1), the intermetatarsal angle (M1M2) and the position of the sesamoids in relation to mechanical axis of M (according to the Research Committee of the American Orthopedic Foot and Ankle Society) were determined on preoperative X-rays. During the procedure, lateral release was performed in several steps: sectioning the metatarsosesamoid suspensory ligament then sectioning the phalangeal insertional band (PIB) and complete detachment of the adductor on the fibular sesamoid ligament. We measured the changes in the M1P1 and M1M2 angles during this step-by-step release. The M1P1 angle decreased during each step of release and went from 29.9° to 11.1° (P<0.001). The M1M2 decreased by 1.70° following medial capusolorrhaphy. Simple capsulorrhaphy reduced the hallux valgus deformity by 8.2° (44%). Release of the metatarsosesamoid suspensory ligament resulted in a decrease of 3.9° (or 21% of total release), release of the PIB in a decrease of 5.1° (27%) and complete detachment of the adductor in a decrease of 1.5° (8%). Thirty six percent of the sesamoids were reduced after metatarsosesamoid ligament resection, 56% after PIB release, and 60% after adductor release. Lateral soft tissue release is ensured in most cases by sectioning the metatarsosesamoid suspensory ligament and the PIB. Release of the adductor from the fibular sesamoid has a limited effect. Lateral soft tissue release should include sectioning the metatarsosesamoid suspensory ligament and detaching the PIB. This release should be enough to correct the deformity without performing any osteotomy in hallux valgus with M1P1<27° and M1M2<10°, as long as a stable medial plane can be obtained. Level IV.