Supination stress of the great toe for assessing intraoperative correction of hallux valgus.

BACKGROUND: We have devised a new intraoperative technique (supination stress of the great toe) in which correction of hallux valgus and metatarsus primus varus, and reduction of the sesamoids could be simultaneously obtained at hallux valgus surgery. The purpose of this study was to prospectively investigate the efficacy of supination stress for assessing intraoperative correction of hallux valgus.

METHODS: Thirty patients (31 feet) with an average age of 59.8 years who had hallux valgus were treated with a proximal metatarsal osteotomy. Supination stress under traction was manually applied to the great toe after release of the distal soft tissues and a proximal metatarsal osteotomy. C-arm fluoroscopy was used to verify correction of hallux valgus and to obtain dorsoplantar non-weightbearing images under supination stress. The dorsoplantar non-weightbearing fluoroscopic images were assessed preoperatively and at the time of intraoperative supination stress. The hallux valgus and intermetatarsal angles were measured. The position of the medial sesamoids was classified with a grading system ranging from I to VII as described by Hardy and Clapham. We defined a grade of IV or less as the normal position of the sesamoids and grade V or greater as lateral displacement of the sesamoids.

RESULTS: The average hallux valgus angle was 34.3° preoperatively and 11.9° at the time of intraoperative supination stress. The average intermetatarsal angle was 16.4° preoperatively and 5.5° at the time of intraoperative supination stress (p < 0.0001, p < 0.0001, respectively). At the time of intraoperative supination stress, the hallux valgus angle was 20° or less in all feet, and the intermetatarsal angle was 10° or less in all feet. Preoperatively, all feet were classified as having lateral displacement of the sesamoids. At the time of intraoperative supination stress, all feet were classified as having normal positioning of the sesamoids.

CONCLUSIONS: Supination stress of the great toe was an effective maneuver for assessing intraoperative correction of hallux valgus and metatarsus primus varus, and reduction of the sesamoids.