A multicentre retrospective study of the impact of body mass index on clinical and functional outcomes of total knee arthroplasty: An Indian prospective

Abstract

ObjectiveTo study the impact of body mass index (BMI) on the outcomes of total knee arthroplasty (TKA) in primary osteoarthritis (OA) patients with CR/PS TKS. MethodsWe conducted a retrospective analysis of data from the ongoing, prospective Freedom 400 study, involving 259 patients. Patients were grouped based on the BMI (WHO categorization): Cohort 1 (normal weight, BMI 18.5 kg/m2 to 25.00 kg/m2), Cohort 2 (overweight patients, BMI 25.00 kg/m2 to 29.99 kg/m2), and Cohort 3 (class 1 and 2 obese patients, BMI 30.00 kg/m2 to 39.99 kg/m2). The primary endpoint was implant survivorship and cumulative revision rates. Secondary endpoints included Knee Society score (KSS), Range of Motion (ROM), Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, SF-36 questionnaire for assessing quality of life (QoL), and radiographic analysis up to a 3-year follow-up period. Results were considered significant at p < 0.05. ResultsA total of 252 patients completed the 3-year follow-up. Women dominated each group (79 %, 78 %, and 83 %, respectively). Average BMIs (Kg/m2) were 22.11 ± 1.78, 27.09 ± 1.39, and 33.08 ± 2.67, respectively. Adverse events were significantly low. Clinical KSS scores improved significantly at 6 weeks (p < 0.001) and continued to improve up to 3 years. Similar patterns were observed in functional KSS scores. WOMAC scores showed significant improvements in pain, stiffness, and degree of difficulty across all groups at 3 years (p < 0.001). Also, ROM improved post-operatively, reaching 122.42° ± 6.43°, 122.67° ± 5.34°, and 122.21° ± 5.68° in Groups 1, 2, and 3, respectively. Radiographical assessments at 12 months (n = 211) and beyond showed no wear or osteolysis. X-ray images displayed favourable functionality of the CR/PS TKS. ConclusionsThis study affirms that BMI does not adversely affect TKA outcomes in primary OA patients. The CR/PS TKS demonstrates high clinical effectiveness, safety, and notable improvements in functional and QoL outcomes across all BMI groups over a 3-year period.