A prospective observational comparative study about foot pressure pattern of patients with knee osteoarthritis undergoing total knee arthroplasty

Background: Knee osteoarthritis (OA) alters lower limb alignment and gait biomechanics. This study used a pedobarographic mapping system to evaluate early changes in dynamic single-leg stance plantar pressure distribution in OA patients undergoing total knee arthroplasty (TKA) compared to healthy controls. Methods: In this prospective study, 33 patients undergoing primary TKA and 33 healthy controls were evaluated. Clinical status (Knee Society score (KSS) and Visual Analogue Scale (VAS) score) were measured pre-operatively. Single-leg plantar pressure distribution across nine anatomical zones (M1–M9) were measured preoperatively (T0), immediate post operatively (T1) and postoperatively at 6 weeks (T2) and 3 months (T3). Results: TKA significantly improved clinical outcomes; mean VAS decreased from 8.91 to 0.84 and mean KSS improved from 38.03 to 88.39 at 3 months. Preoperatively, OA patients exhibited abnormal loading concentrated over the great toe (M1) and lateral deficits, differing significantly from controls (p<0.05). Postoperatively, significant progressive pressure redistribution occurred at 6 weeks (M2, M4, M8) and 3 months (M2, M7, M8, M9). By 3 months, pressure patterns approached control baselines, with residual differences limited only to the M4 and M5 regions (p<0.05). Conclusions: Coronal realignment through TKA drives rapid postoperative redistribution of plantar pressures toward normal physiological patterns, aligning with marked clinical recovery. However, persistent lateral forefoot deficits at 3 months suggest that complete biomechanical adaptation requires a longer recovery period.