Pes Planus Does Not Negatively Affect Clinical Outcomes after Hallux Valgus Surgery

Abstract

Category: Bunion; Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Pes planus is associated with hallux valgus development. Increased forefoot abduction and pressure through the hallux during the heel-rise phase of the gait in a pes planus foot is believed to contribute to hallux valgus formation. These abnormal forces through the hallux may result in poorer healing and more residual pain after surgical correction. We investigated if patients with increasing severity of pes planus presented with more severe hallux valgus deformity and whether these patients had more residual pain and poorer function following hallux valgus surgery. Methods: We evaluated 191 consecutive cases of hallux valgus surgery with Scarf osteotomy as the primary procedure. American Orthopaedic Foot & Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale, visual analog scale (VAS), Short Form-36 physical component summary (SF-36 PCS), mental component summary (SF-36 MCS) and a satisfaction questionnaire were assessed at baseline, 6 months and 24 months postoperatively. Pes planus angles measured were the talonavicular coverage angle (TNCA), lateral talus-first metatarsal angle (Meary's angle) and lateral talocalcaneal angle (LTCA). The cohort was stratified into controls (0°-4.0°), mild (4.1°-14.9°), moderate (15.0°-30.0°) and severe (>30.0°) pes planus groups according to Meary's angle. Clinical outcomes were compared among the groups. Multiple regression was used to determine association between pes planus angles and outcomes. Results: There were 78 controls, 95 mild, 18 moderate and no severe cases of pes planus. Meary's angle was independently associated with preoperative HVA (beta 0.408, 95% CI 0.104-0.712, P =.009). Patients with mild and moderate pes planus had significantly greater preoperative HVA (P <.001) compared to controls. Pes planus angles were not associated with pre- or postoperative VAS, AOFAS score, SF-36 PCS or SF-36 MCS. Among controls, mild and moderate pes planus groups, there were no significant differences in pre- or postoperative clinical scores (Table 1), and satisfaction was 84.6, 80.0% and 77.8%, respectively (P =.667). Conclusion: Patients with increasing severity of pes planus presented with greater severity of hallux valgus deformity. However, patients with pes planus had similar pre- and postoperative clinical outcomes and satisfaction after hallux valgus surgery in comparison to patients with neutral foot arches.