The influence of the length of the first metatarsal on transfer metatarsalgia after Wu's osteotomy

BACKGROUND: The aim of this study was to evaluate how changes in the length of the first metatarsal, hallux valgus angle (HVA), intermetatarsal 1-2 angle (IMA), plantar angulation and sesamoid position influence the severity of the postoperative 2-5 metatarsalgia and to determine patient satisfaction with the cosmetic outcome after Wu's osteotomy. MATERIALS AND METHODS: A retrospective analysis of the clinical data and radiographs of 87 cases was performed at a mean followup time of 4.2 years after Wu's subcapital cross osteotomies. RESULTS: The mean HVA decreased from 42 to 13 degrees, the mean IMA 1-2 from 22 to 10 degrees. The mean first metatarsal lengthening was 0.3 mm. A negative correlation was found between lengthening of the first metatarsal and metatarsalgia at rays 2 and 3. No such pattern was found between the fourth and fifth metatarsal. No correlation was found between the 2-5 metatarsalgia and the decrease in either the HVA or the IMA 1-2. A positive correlation was detected between the HVA decrease and the patients' satisfaction with their postoperative foot alignment; there was no correlation between the perceived postoperative foot alignment and either the first metatarsal lengthening or the IMA 1-2 decrease. CONCLUSION: Preservation of the length of the first metatarsal during osteotomy seems to prevent the postoperative transfer metatarsalgia on the second and third rays; however, it has no major influence on the satisfaction of the patients with their foot alignment. A greater correction of the HVA angle resulted in a higher level of satisfaction with the foot cosmesis.