Potential for recurrence of hallux valgus after a modified Hohmann osteotomy: a biomechanical analysis.

On the basis of a biomechanical model the present study investigates whether a foot-widening effect, which may result in recurrence of bunions, can be demonstrated in operated patients. Therefore, the medial deviation of the first metatarsal head as a result of flexion forces on the hallux was measured in eight patients with clinical idiopathic hallux valgus, who underwent a modified Hohmann osteotomy, and in eight "normal" persons. We found that (1) before osteotomy, all forefeet broadened while pressing the big toe downward, and (2) after surgery, widening of the forefeet on average had significantly diminished, but still existed, which might explain the development of recurrences. (3) After surgery, the patients showed a slight, but statistically nonsignificant, decrease (from 37 N to 25 N) of the isometrically determined average maximal applicable flexion force. These abnormal hallux loads may cause, or result from, a deviation in gait pattern.