Changes in plantar pressure, contact area and contact time symmetry during the gait 4 weeks before and 12 and 24 weeks after unilateral total hip arthroplasty.

Abstract Background Foot to ground pressure changes in total hip arthroplasty patients' gait are not widely described, although they are sensitive to gait abnormalities and the distribution of plantar pressures may differ before and after the surgery. This study aimed to analyse longitudinally differences in plantar pressure during gait in total hip arthroplasty patients compared to healthy controls. Methods Eighteen males participated in this study. Eight males, who underwent unilateral total hip arthroplasty, participated at the data collection three times: 4 weeks before the surgery, 12 and 24 weeks after, and ten healthy controls. All participants were asked to walk over Emed platform. To compare differences between the affected and unaffected limbs, Kolmogorov-Smirnov test was used. Kruskal-Wallis test was used to compare the difference between total hip arthroplasty patients and healthy controls. Findings Statistically significant differences between the affected and unaffected limb were observed only during the preoperative measurement in peak pressure at MH4 area and in the contact area at MH4 and big toe. When comparing total hip arthroplasty patients and controls, a difference in the contact time at MH2, MH3 and MH4 areas 12 weeks after surgery and at MH2 and MH4 24 weeks after the surgery were observed. Interpretation The shorter contact time at forefoot areas may indicate an alteration in the propulsive phase of the gait of both the affected limb and unaffected limb in total hip arthroplasty patients as a result of decreased terminal hip extension during the stance phase described in previous studies.