Immediate effect of hallux valgus surgery on the biomechanical behavior of the first ray

BACKGROUND: The surgical treatment of hallux valgus (HV) deformity has been the subject of countless publications but few focus on the altered windlass mechanism or analyze the biomechanical behavior immediately after surgery.
METHODS: Patients treated for HV between January and March 2023 were included. The surgery consisted of a L-reverse first metatarsal osteotomy. To analyze the windlass mechanism we record two different measurements; the isolated first metatarsophalangeal joint (MTPJ) dorsiflexion angle (IDA) and dynamic plantarization of the first metatarsal head when performing first MTPJ dorsiflexion imprinting a mark on a modeling foam.
RESULTS: A total of 30 patients diagnosed with symptomatic HV were included. In all patients, a change in the IDA angle was evident, being overall statistically significant. About modeling foam imprinted mark, all measurements, in all planes of space, had a clear tendency to increase, which turned out to be statistically significant (p < 0.001).
CONCLUSIONS: An altered windlass mechanism may be successfully recovered immediately after hallux valgus deformity surgery. This could be evinced by an indirect measurement analyzing the imprint of the head of the first metatarsal in a modeling foam and the IDA.