End-stage knee osteoarthritis with and without sarcopenia and the effect of knee arthroplasty – a prospective cohort study

Abstract

Background: Sarcopenia often accompanies osteoarthritis (OA) which is managed by total knee arthroplasty (TKA) in late stage. Recent studies have suggested higher risk of post-operative complication after TKA in sarcopenic OA subjects but whether TKA can benefit them as for non-sarcopenic subjects remain unexplored. This study aims to examine the dynamic, mutual impact of sarcopenia and TKA in their one-year post-operative period.Methods: This prospective cohort study was conducted between 2015 to 2018 at our hospital. Patients with end-stage OA of the knee waiting for TKA were recruited into the study. Primary outcome measures were change in muscle strength, mass and function. Secondary outcome measures were Quality of Life (QOL) measurements in pain, psychological and physical health.Results: Fifty-eight patients were recruited, of which 79.3% were female and 32.8% already had sarcopenia at baseline. The average age of sarcopenic subjects and non-sarcopenic subjects were comparable (67.89±7.07 vs. 67.92±6.85; p=0.99) and sarcopenic subjects had lower body mass index (BMI) (25.64±2.64 vs. 28.57±4.04; p=0.01). There was a statistically significant improvement in walking speed (10.24±5.35 vs 7.69±2.68, p<0.01) and muscle strength in both sarcopenic and non-sarcopenic patients after TKA. This was accompanied by an improvement trend in muscle mass in all subjects. There was no change in handgrip power before and after TKA and subsequent follow-up (p=0.97). Quality of life measured with WOMAC, SF12v2 and IPAQ revealed progressive significant improvement (p≤0.01). Further analysis at the IPAQ also found increased engagement of high-intensity activities.Conclusions: This study showed that sarcopenia among patients with end-stage OA of the knee is not uncommon but both sarcopenic and non-sarcopenic OA patients could reach significant clinical and functional improvement after TKA. Further studies with increased sample size and different ethnicities can help ascertain a beneficial role of TKA on sarcopenic OA subjects.