Gait Kinematics and Knee Stability 10-Years Following Posterior-Stabilised Total Knee Arthroplasty Comparable to Healthy Adults >55

Purpose: The purpose of this study was to compare the long-term objective biomechanical and functional parameters of a high-flexion total knee arthroplasty (TKA) design against healthy older adults to determine whether knee biomechanics are comparable in both populations.

Methods: One cohort of patients with a primary TKA, and a cohort of healthy adults over 55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, and gait patterns were analysed with a 3D-motion capture system. An arthrometer quantified anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS software (α = 0.05).

Results: 23 knees were replaced in 20 patients. At 9.8±3.1 years postoperatively, the patients’ knees had a statistically significant poorer RoM than healthy controls’ knees (n=23) due to limited flexion; p<0.0001. Patients also failed to achieve the same degree of knee flexion as controls during downhill gait. No kinematic differences were observed during mid-flexion in level nor downhill gait; a state that has been associated with instability (p=0.614; not significant (n.s)). There were no differences between groups in knee laxity (n.s).

Conclusion: Patients in this study had similar gait patterns to healthy older adults during mid-flexion, and were no more likely than the healthy controls to exhibit anterior-posterior translation of the knee >7mm; a known risk factor of instability. However, the knee flexion range was poorer. This likely led to bilateral pathological knee flexion patterns during downhill gait.