Functional outcome assessment of total knee arthroplasty using the knee society score: a prospective single-centre study from a tertiary care hospital in Lucknow, Uttar Pradesh

Abstract

Background: Knee osteoarthritis (OA) is a leading cause of chronic pain and functional disability, disproportionately affecting elderly individuals in low- and middle-income countries. Total knee arthroplasty (TKA) is the definitive treatment for end-stage disease, yet outcome data from tertiary care hospitals in Uttar Pradesh using validated scoring tools remain limited. Objectives were to assess the preoperative and postoperative functional outcomes of patients undergoing primary TKA using the Knee Society Score (KSS), and to examine associations between functional outcome and patient-level demographic variables.

Methods: A hospital-based prospective observational study was conducted in the Department of Orthopaedic Surgery, Balrampur Hospital, Lucknow, from September 2024 to August 2025. Sixty-five consecutive patients with primary knee OA undergoing primary TKA were enrolled. Patients with inflammatory or post-traumatic arthritis, revision surgery, active infection, or neuromuscular disorders were excluded. Functional outcome was assessed using the two-component KSS (Knee score and functional score) preoperatively and at 12-month follow-up. Preoperative-postoperative comparison was performed using paired t-test; associations between functional outcome category and demographic variables were assessed using the chi-square test (p<0.05 considered significant).

Results: Mean patient age was in the sixth decade, with female predominance (63.1%). The mean Knee Score improved from 41.6±8.9 preoperatively to 86.9±6.7 at 12 months (mean difference 45.3; p<0.001), and the mean functional score from 38.2±9.4 to 82.4±7.9 (mean difference 44.2; p<0.001). Excellent outcomes were achieved in 73.8% of patients and good outcomes in 18.5%, yielding a combined excellent-to-good rate of 92.3%. Patients aged ≥60 years demonstrated significantly better functional outcomes than younger patients (p=0.024). Gender and body mass index did not independently influence postoperative functional scores. No cases of deep infection or revision surgery were recorded during follow-up.

Conclusions: Primary TKA produces significant, sustained improvement in knee function and mobility at one year, achieving excellent-to-good outcomes in over 90% of patients. The KSS is a reliable and responsive instrument for routine outcome audit. Appropriate patient selection, structured rehabilitation, and targeted expectation management-particularly in younger patients-are key determinants of optimised postoperative results.