Prevalence of flat foot in patients undergoing total knee arthroplasty: A retrospective survey

Abstract

Purpose: In our hospital, four of five patients who underwent triple arthrodesis for the treatment of stage III posterior tibial tendon dysfunction (PTTD) had previously undergone an ipsilateral or contralateral total knee arthroplasty (TKA). A survey was hence conducted to explore a possible association between severe knee osteoarthrosis (OA) and the onset of PTTD.

Methods: Foot-printing was conducted to evaluate the prevalence of flat foot in 200 foot of 100 patients who had undergone TKA. The correlation between femoro-tibial angles (FTA) and the prevalence of flat foot was also investigated.

Results: Flat foot were observed in 38 foot of 27 patients. However, there was no significant statistical difference between FTA and the prevalence of flat foot.

Discussion: Patients with severe knee OA frequently have a toe-out gait. Analyses of standing radiographs showed that the hip-calcaneus line, drawn from the femoral head through the bottom of the calcaneus with a toe-out leg position, passed through the inner side of the knee joint and metatarsus, farther than that of a toe-straight leg position. The resulting increased pressure on the tibialis posterior tendon and spring ligament can cause flat foot. Therefore, the higher prevalence of flat foot in patients with severe knee OA may be, in part, due to the toe-out gait.

Conclusion: While there was no significant difference between FTA and the prevalence of flat foot, it is considered that a toe-out gait may be related to the prevalence of flat foot.