Evaluation of hallux valgus surgery using computer-assisted radiographic measurements and two direct forefoot parameters

Abstract

Computer-assisted measurements on radiographs were used to evaluate hallux valgus surgery in 11 ft in eight patients undergoing scarf osteotomy. Hallux valgus angle and intermetatarsal angles give an indirect measure of reduction of forefoot dimensions. In this study, the dimensions at forefoot before and after surgery were quantified using two direct linear parameters and these were correlated with angular measurements. With the patient standing the maximum circumference at the forefoot was measured before and at 3 months after surgery. An average reduction of 14.2 mm was noted. On weight bearing anteroposterior radiographs of the foot, the distance between the most prominent points on the outer cortex of heads of first and fifth metatarsals was measured on preoperative radiographs and those obtained at final follow up. This measurement termed by author VKP the ‘metatarsal span’ showed an average reduction of 7.26 mm. Average reduction of hallux valgus angle was from 41.35 to 15.71°, intermetatarsal angle from 14.81 to 7.67° and distal metatarsal articular angle from 28.82 to 8.69°. The computer-assisted measurements evaluate radiographic parameters in hallux valgus surgery with digital accuracy. The reduction in metatarsal span correlates best with reduction in intermetatarsal angle. These direct linear forefoot parameters help in addition to the usual parameters to evaluate the reduction of forefoot dimensions objectively, assisting comparison between different surgical techniques.