Long-term influence of total knee arthroplasty on patients' biomechanics, body mass index and clinical outcomes: a 7-year follow up

Abstract

Total knee arthroplasty (TKA) is widely considered as the most viable and successful management option to improve pain and quality of life for patients with severe knee osteoarthritis (OA). However, many patients who had undergone TKA have residual anterior knee pain, impaired functional performance and lower limb biomechanics after surgery. These impaired lower limb biomechanics may lead to altered distribution of forces across the knee joint, which in turn could be one of the factors responsible for prosthesis failure; another common factor of prosthesis failure is patients presenting high body mass index (BMI). However, the association between impaired biomechanics, BMI and clinical outcomes of patients after TKA are yet to be investigated both immediately and at long-term. Understanding if these modifiable factors influence clinical outcomes of patients that had undergone TKA may shed some light on the underlying factors linked to the high rates of patients unsatisfaction and revision after TKA. Therefore, the aim of this project is to conduct a 7-year follow-up of a cohort of patients who had undergone TKA and control participants to investigate the trunk and lower limb biomechanics, BMI and clinical outcomes. Seven-year follow-up data will be derived from a cohort (n = 80) that included patients who had undergone TKA (TKA group) and control participants (control group) who underwent a biomechanical assessment in the gait laboratory of La Trobe University (1 year after TKA). All participants from the original cohort (n = 80) were invited by email or telephone to participate in the follow-up study, 7 years after the first timepoint assessment (1 year after TKA), and 48 participants (TKA group [n = 26]; control group [n = 22]) responded our invitation and consented to participate. Demographic data (age, height, body mass), the American Knee Society Score (AKSS) and the Total Knee Function Questionnaire (TKFQ), will be collected prior to testing. Then, participants will undergo a kinematic assessment of trunk and lower limb biomechanics during four functional activities (walking, a standing squat whilst weightbearing on both limbs, lunging in stride stance with the operated limb placed in front of the body, and lunging in stride stance with the operated limb placed behind the body) using a 12 camera Vicon MX3 Motion Analysis System. A multivariate mixed-model analysis of variance (ANOVA) will be used with time (1-year follow-up, 7-year follow-up) as a within-subject variable and group (TKA group, control group) as a between-subject variable, to examine effects of TKA on trunk, pelvis and knee biomechanics and BMI. A Pearson product-moment correlation matrix will be used to explore the association among trunk and lower limb biomechanics, BMI and clinical outcomes (pain and functional capacity) of patients who had undergone TKA at two timepoints (1 year after TKA and 7 years after TKA). (AU)