Assessment of Functional Outcome after Total Knee Replacement: A Prospective Observational Study

Abstract

Background: Total knee arthroplasty (TKA) is an established surgical intervention for advanced symptomatic knee osteoarthritis when conservative treatment fails to provide adequate pain relief and functional restoration. Although implant survivorship remains an important measure of surgical success, contemporary assessment increasingly emphasizes patient function, pain, mobility, and ability to perform activities of daily living. The present study assessed the temporal pattern and magnitude of functional recovery following primary total knee replacement.

Methods: A prospective observational study was conducted among 100 adults undergoing primary unilateral TKA for advanced knee osteoarthritis. Patients were evaluated preoperatively and at 6 weeks, 3 months, and 6 months postoperatively. Functional outcome was assessed using the Knee Society Knee Score (KSS-Knee), Knee Society Function Score (KSS-Function), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analogue scale (VAS) for pain, and knee range of motion (ROM). Longitudinal changes were analyzed using paired and repeated-measures statistical testing, and multivariable logistic regression was used to identify determinants of high functional status at 6 months.

Results: Mean age was 65.8 ± 7.3 years, and 68% of participants were women. KSS-Knee improved from 41.8 ± 11.5 preoperatively to 84.6 ± 9.8 at 6 months, while KSS-Function increased from 38.6 ± 14.2 to 79.2 ± 15.1 (both p<0.001). WOMAC decreased from 61.3 ± 11.9 to 22.6 ± 10.5, and VAS pain decreased from 7.4 ± 1.1 to 2.0 ± 1.2 (p<0.001). Mean knee flexion increased from 92.4° ± 12.1° to 111.8° ± 9.6°. Higher preoperative functional status and greater flexion at 6 weeks independently favored high 6-month function, whereas advanced age and multiple comorbidities were associated with less favorable recovery. Overall satisfaction was 88%.

Conclusion: Primary TKA produced substantial improvements in pain, knee-specific function, mobility, and activities of daily living, with the greatest recovery occurring during the first 3 months and continued improvement through 6 months. Early functional assessment may assist in identifying patients requiring intensified rehabilitation.