Pedobarographic Analysis in Total Knee Arthroplasty.

ABSTRACT

Pedobarographic gait analysis is a useful tool for the determination of loading distributions and alterations on the lower extremity and their reflection on the foot sole after many orthopaedic surgical applications. To date, there have been no studies evaluating the relationship between component alignment and changes of pedobarographic gait analysis in total knee arthroplasty (TKA). We aimed to investigate the effects of TKA and prosthetic alignment on the distribution of pedobarographic parameters. Quantitative gait patterns of 47 patients were prospectively evaluated by using pedobarography 1 week before surgery and at the seventh month, on average, postoperatively. Component positions were assessed, and all applications were divided into three groups according to tibial component position as varus, neutral, and valgus. Pedobarographic results were compared between pre- and postoperative values for all applications and compared among the groups. Mean postoperative tibiofemoral angle was 5.4 degrees in valgus, and preoperative knee scores were markedly improved postoperatively. The range of tibial component alignment changed between 1 and 4 degrees in the varus and valgus groups. Plantar loading parameters (force and pressure) were significantly decreased in all operated knees, especially in forefoot and midfoot. In varus tibial components, plantar loading values decreased in midfoot and hindfoot. However, in the neutral and valgus groups, similar alterations of plantar loadings were obtained, which included decreasing in forefoot and midfoot with significant increase in hindfoot. Plantar loading distribution changed statistically significantly after TKA despite good clinical and radiographic results. Tibial component alignment was also responsible for plantar loading distribution. Tibial components in varus position create different foot loading characteristics compared with neutral and valgus aligned components. Pedobarographic evaluation in TKA allows clinicians to obtain a proper understanding of abnormal gait caused by component malposition.