Proximal oblique-domed osteotomy of the first metatarsal for the treatment of hallux valgus associate with flat foot: effect to the correction of the longitudinal arch of the foot

Introduction Flat foot and/or metatarsal primus varus are the major causes of hallux valgus, and it is important to correct these deformities in order to prevent the recurrence of this condition. We demonstrate the clinical and radiological assessment of the correction of hallux valgus, metatarsal primus varus, and flat foot after proximal oblique-domed osteotomy of the metatarsus with distal soft tissue reconstruction. Materials and methods Twenty-seven feet of 22 patients with moderate or severe hallux valgus who had undergone proximal oblique-domed osteotomy were studied. After the adductor hallucis tendon was cut at the attachment of the proximal phalanx and at the sesamoid bone, the osteotomy was performed 3 cm dorsal-distal to the metatarsocuneiform joint to transfer distal fragment approximately 5 mm in the plantar direction, and rotated laterally decreasing the first–second intermetatarsal angle to 5 degrees. Results The mean AOFAS score was 54.1 ± 2.8 points at pre-operation and 92.8 ± 4.8 points at the most recent follow-up (P < 0.0001). Significant improvement was seen between the hallux valgus angle (P < 0.0001), first–second intermetatarsal angle (P < 0.0001), first–fifth intermetatarsal angle (P < 0.0001), talar pitch (P = 0.0032), and calcaneal plantar angle (P = 0.0327) before surgery and at one year after surgery. The average improvement of the talar pitch and calcaneal plantar angle was 2.6 ± 1.4 and 2.4 ± 1.5 degrees, respectively. Conclusion This study suggest that proximal oblique-domed osteotomy of the metatarsal as a surgical procedure for the treatment of moderate or severe hallux valgus with flat foot can be recommended to correct the longitudinal arch of the foot and the first–second intermetatarsal angle.