Proximal opening-wedge osteotomy of the first metatarsal for moderate and severe hallux valgus with low-profile plates

Abstract

Objective: The objective of this study was to present the results of the treatment of moderate and severe hallux valgus with the proximal metatarsal opening wedge (PMOW) osteotomy using two different screw and plate fixation systems. Methods: Forty one patients (70 feet) were treated in a period of 4 years (2005 to 2009) with an average follow-up of 2.4 years. Age varied from 19 to 83 years with an average of 52 years. As for sex, 93% of the patients were female and 7% were male with a gender proportion of 13: 1. The fixation of the PMOW osteotomy was obtained by the Darco® BOW plate in 36 feet (51%) and by the Arthrex® LPS in 34 feet (49%). Both techniques are similar and the lateral cortex was violated in 31% of the cases (22 feet). Biplanar chevron distal osteotomy and/or Akin proximal phalangeal osteotomy were associated according to the magnitude of the distal metatarsal articular (DMMA) and hallux valgus interphalangeus (HVI) angles. Pre and post-operative weight-bearing radiographs were measured to compare the following radiographic variables: hallux valgus angles (HVA), I-II intermetatarsal angle (IMA), DMAA, HVI, relative lengths of I and II metatarsals and sesamoid position. The pre and post operative American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score were recorded for each patient. Results: The HVA improved by a mean of 14°; the IMA improved by a mean of 8°, the DMAA improved by a mean of 11° and the HVI improved by a mean of 7°. No changes in the relative lengths of I and II metatarsals were detected. According to the sesamoid position, 79% of the feet have improved and 32% have been normalized this variable. The AOFAS forefoot score improved from a mean of 50 to 82. There were five painful hardware, five persistent swelling, two nonunion, two tarsometatarsal dislocation and six other minor complications. Conclusion: The PMOW osteotomy is an effective method for correcting a moderate or severe hallux valgus deformity. Both screw and plate systems used in this series showed to guarantee the stability and correction of the osteotomy site. The combination with distal biplanar chevron osteotomy and/or Akin osteotomy is advisable to correct the DMAA and HVI angles.