Spontaneous First Metatarsal Rotational Correction by the Syndesmosis Procedure for Hallux Valgus Deformity: A Case Report.

Introduction: If not corrected, the first metatarsal pronation rotation deformity is deemed responsible for the high hallux valgus (HV) deformity recurrence rate. Its correction method by osteotomy and arthrodesis has been recommended, just like the metatarsus primus varus (MPV) deformity correction. Since the pathogenesis of the first metatarsal pronation is not well understood, there may be other surgical approaches to correct it.

Case Report: A 53-year-old female's HV feet presented with severe left hallux pronation, and positive radiological round head and inferior tubercle shift signs of the first metatarsal. She underwent a non-osteotomy non-arthrodesis soft-tissue procedure that was expected to correct the MPV deformity but not the pronation deformity. Post-operative hallux pronation was reversed, and round head and inferior tubercle signs were corrected.

Conclusion: The first metatarsal hypermobility and displacement of HV feet are probably in all three planes. Correction of MPV in the first metatarsal entirety in the transverse plane without osteotomy or arthrodesis can also induce a correction effect on its sagittal and frontal planes.