Gait Dynamics for Level and Inclined Surfaces: A Comparison Between TKA Patients and Healthy Controls

Introduction: Total knee arthroplasty (TKA) has been shown to significantly improve gait dynamics for individuals suffering from severe osteoarthritis(1). However, previous research has limited gait analysis for TKA patients to level surfaces. Gait analysis among young, healthy individuals has shown that lower limb mechanics change as individuals move from level to inclined walking surfaces, with the most pronounced changes occurring at the knee joint (2,3). These changes should be kept in mind when determining functional outcomes for TKA patients with respect to gait analysis. The purpose of this study was to compare gait patterns between TKA patients and controls during both level and inclined tasks. Methods: Sixteen participants (12 M/4 F; age=62±6, BMI=30±3 kg/m2) were recruited from the local hospital for the TKA participant group. Inclusion criteria dictated that participants be between 50-75 years of age, with a BMI ≤35 kg/m2, having undergone unilateral TKA for severe knee osteoarthritis within the past 6-12 months (mean=11±5 months). Control participants (n=16; 12M/4 F; age=63±8, BMI=27±4 kg/m2) were recruited from the local community with similar inclusion criteria, having no lower limb injuries or musculoskeletal diseases. Three-dimensional motion analysis was conducted using 10 Vicon MX cameras; inclined walking trials were performed on a 4 metre ramp set at a 9° (12.5%) incline. Ground reaction forces were calculated using 2 force plates embedded within the respective walkway; kinetic measures were calculated using an inverse dynamics approach. Participant performed 5 trials for each walking task. Individual averages across these trials were calculated for each participant and were later used to calculate group means for each variable of interest. Trials were analyzed and time normalized (for consecutive heel strikes) in a customized Matlab software; statistical analysis was conducted using SPSS 21.0 software. One-way ANOVAs were conducted to compare peak kinematic and kinetic values across walking tasks (Level, Uphill, Downhill) and groups (TKA vs. Control), with an α=0.05. Results: For each of the walking tasks, TKA participants exhibited significantly reduced knee flexion angles in both the early stance (10-30%) and swing (62-100%) of the gait cycle (Table 1), along with reduced power absorption and generation at the knee throughout the gait cycle (Figure 1). It is of interest to note that no significant differences were observed for hip kinematics or kinetics between the TKA and control groups during any of the three walking tasks. During each of the gait tasks TKA patients experienced reduced extension moments during early …