Effects of Sarcopenic Obesity and Its Confounders on Knee Range of Motion Outcome after Total Knee Replacement in Older Adults with Knee Osteoarthritis: A Retrospective Study

Abstract

Sarcopenic obesity is closely associated with knee osteoarthritis (KOA) and has high risk of total knee replacement (TKR). In addition, poor nutrition status may lead to sarcopenia and physical frailty in KOA and is negatively associated with surgery outcome after TKR. This study investigated the effects of sarcopenic obesity and its confounding factors on recovery in range of motion (ROM) after total knee replacement (TKR) in older adults with KOA. A total of 587 older adults, aged ≥60 years, who had a diagnosis of KOA and underwent TKR, were enrolled in this retrospective cohort study. Sarcopenia and obesity were defined based on cutoff values of appendicular mass index and body mass index for Asian people. Based on the sarcopenia and obesity definitions, patients were classified into three body-composition groups before TKR: sarcopenic-obese, obese, and non-obese. All patients were asked to attend postoperative outpatient follow-up admissions. Knee flexion ROM was measured before and after surgery. A ROM cutoff of 125 degrees was used to identify poor recovery post-surgery. Kaplan-Meier curve analysis was performed to measure the probability of poor ROM recovery among study groups. Cox multivariate regression models were established to calculate the hazard ratios (HRs) of postoperative poor ROM recovery, using potential confounding factors including age, sex, comorbidity, risk of malnutrition, preoperative ROM, and outpatient follow-up duration as covariates. Analyses results showed that patients in the obese and sarcopenic-obese groups had a higher probability of poor ROM recovery compared to the non-obese group (all p < 0.001). Among all body-composition groups, the sarcopenic-obese group yielded the highest risk of postoperative physical difficulty (adjusted HR = 1.63, p = 0.03), independent to the potential confounding factors. Sarcopenic obesity is likely at the high risk of poor ROM outcome following TKR in older individuals with KOA.

The relationship between body mass index and clinical efficacy of knee arthroplasty in patients with knee osteoarthritis

“…Obese patients have larger lower limb loads and less rehabilitation training, thus leading to poor knee function recovery. Previous study has shown that BMI levels are negatively associated with lower limb muscle strength and muscle mass, and that obese people with reduced muscle mass are prone to limited activity, all of which limit the recovery of knee function (16). Hyperglycemia leads to the reduction of blood vessels at the incision, the decrease of phagocyte number and phagocytic capacity, the decrease of leukocyte chemotaxis and protein synthesis ability, the decrease of immune responses, and limits the formation of fibroblasts and collagen.…”

Sarcopenia and Sarcopenic Obesity and Osteoarthritis: A Discussion among Muscles, Fat, Bones, and Aging

“…In addition, symptoms and physical impairments that are related to lower limb OA involving joint pain and stiffness, muscle weakness, and reduced sensory function can be deleterious to balance performance and contribute to the probability of falling. Moreover, changes in joint structure, such as osteophyte formation and cartilage degeneration, may alter mobility patterns, which may in turn negatively impact balance [ 62 , 63 , 64 , 65 , 66 ]. Further, gait analysis reveals that gait differs in adults with antero-lateral and posterior exposure during hip arthroplasty compared to healthy ones [ 67 ].…”

Association between sarcopenic obesity and knee osteoarthritis: A narrative review

“…Hence, the presence of sarcopenia and obesity within the same individual could potentially accelerate OA disease progression because sarcopenia confers additional risks besides the consequences of excess adiposity. Furthermore, obesity alters gait parameters, including stride length and stance, leading to reduced gait speeds [ 51 ]. Muscle weakness also alters gait kinematics [ 3 ] and the compounded influence of sarcopenia and obesity could impact joint biomechanics.…”