EFORT Michael Freeman Award 2020: Knee biomechanics before and after total knee arthroplasty with either a medial pivot or posterior stabilized implants.

Abstract

Can the design of a total knee replacement affect how patients walk and their reported outcomes compared to healthy adults, considering age and body mass index (BMI)? Many studies have produced conflicting results, often not including a pre-operative assessment and relying on discrete measurements. Twenty-eight patients randomly received either a medial-ball-and-socket (n = 14, age = 62.7(5.8) years, BMI = 27.0(3.8)kg/m², females = 6) or posterior-stabilized (n = 14, age = 64.5(8.1) years, BMI = 29.8(3.4)kg/m², females = 6) implant and completed a gait analysis before and 12 months following total knee arthroplasty and were compared to 14 healthy controls (age = 64.4(5.6) years, BMI = 24.9(2.1) kg/m², females = 7). Temporospatial, knee biomechanics and patient-reported outcome measures were measured during five gait trials. Knee biomechanical measures were evaluated across the gait cycle using statistical parametric mapping. Preoperatively, the medial-ball-and-socket and posterior-stabilized were similar, with no differences in age, BMI, patient-reported outcome measures, or knee biomechanics (P > .05). Pre-operatively, compared to controls, both medial-ball-and-socket and posterior-stabilized had different movement patterns, primarily in stance and swing phase knee flexion angles (P < .05). Postoperatively the medial-ball-and-socket had less knee flexion angle during stance phase compared to the controls (P < .05), whereas the posterior-stabilized walked with less knee flexion angle than the controls during stance and swing phase (P < .05). The medial-ball-and-socket group demonstrated a gait pattern more closely resembling that of the controls compared to the PS group, exhibiting fewer differences in sagittal knee angles. Although both groups showed post-operative improvement across all patient-reported outcome measures, no significant differences were detected between them. NCT02589197, October 28, 2015.