Does the presence of pes planus deformity increase recurrence of hallux valgus deformity following surgery?

L. Weigelt, G. Heyes, A. Vosoughi, L. Mason, A. Molloy

Background: Risk factors for Hallux Valgus include; shod footwear, genetic factors, metatarsal morphology, ligamentous laxity and Pes Planus. Loss of arch increases Hallux plantar medial pressures and drives deformity during heel rise. Elevation of Hallux with defunctioning of Peroneus Longus, hindfoot eversion and forefoot abduction also contribute. There is little in the literature regarding whether Pes Planus is associated with increased recurrence rates.

Methods: This paper reports a restrospective review of 183 consecutive Hallux valgus cases performed 07/03/2008-05/12/2017. Follow up for at least six months . X-rays were performed at six weeks, three months and at six and/or 12 months . We examined Sesamoid location (Hardy and Clapham Classification), Hallux Valgus Angle (HVA), Intermetatarsal Angle, Meary's angle and Talonavicular uncovering.

Results: 12 were excluded due to previously amputated second toes, Hallux Varus, revision surgery and loss to follow up. Of the 171 remaining cases 75 had Pes Planus (Meary's < -4^o). 144/171 (84.2%) cases had HVA correction to < 15^o. The incidence of recurrent HVA > 15^o was significantly higher in those with Meary's angle < - 4^o (Chi-Sq P-value0.000002). Those with a Meary's angle -20^o to -10^o had a significantly higher rate of recurrence than ones measuring -10^o to -4^o (Chi-Sq P-value0.0018). 51/75 (68%) breaks in Meary's line were located at the Naviculocuneiform joint. Overall progression of deformity was no different between those initially corrected post surgery to HVA < 15^o (Chi-Sq P-value0.61) and those not. Multiple regression analysis revealed there was no meaningful association with sesamoid location and recurrence.

Conclusions: Our results demonstrate a link between Pre-operative Pes Planus deformity and increased recurrence rates of Hallux Valgus deformity following surgery.