Background: Knee osteoarthritis (OA) is a common musculoskeletal condition characterized by joint pain, stiffness, reduced muscle strength, and functional limitations. These impairments can affect walking, stair climbing, balance, and activities of daily living. Open kinetic chain (OKC) and closed kinetic chain (CKC) exercises are commonly used in physiotherapy to improve muscle strength and functional performance in individuals with knee OA.

Objective: To compare the effects of open kinetic chain exercises and closed kinetic chain exercises on pain and functional performance in individuals with mild to moderate knee osteoarthritis.

Methodology: This comparative experimental study included 40 participants with mild to moderate primary or secondary knee osteoarthritis, randomly allocated into two groups of 20 participants each. Group A received closed kinetic chain exercises (CKCE), while Group B received open kinetic chain exercises (OKCE). The intervention was conducted over 13 weeks, with progressive exercise protocols. Outcomes were assessed before and after the intervention using the Visual Analogue Scale (VAS) for pain, the 3-Metre Walk Test for walking performance, the Stair Climb Test for functional ability, and the Single-Leg Stance Test for balance. Thirty-seven participants completed the intervention, while three participants discontinued or were lost to follow-up.

Results: Both groups demonstrated improvements in pain and functional performance following the intervention. In the CKCE group, mean VAS scores decreased from 6.35 to 4.25, while the OKCE group showed a reduction from 5.80 to 3.45. The CKCE group demonstrated a reported mean improvement of 1.10 in the 3-Metre Walk Test and 8.22 in the Single-Leg Stance Test. The OKCE group demonstrated a reported mean improvement of 5.85 in the Stair Climb Test and 5.03 in the Single-Leg Stance Test. Within-group analyses indicated statistically significant improvements in several outcome measures. However, inconsistencies in the reported between-group statistical results require verification before definitive conclusions can be drawn regarding comparative effectiveness.

Conclusion: Both open and closed kinetic chain exercise programmes appear to be beneficial for improving pain and functional performance in individuals with knee osteoarthritis. The findings support the use of structured therapeutic exercise in physiotherapy management. Further analysis using verified data and appropriate between-group statistical tests is required to determine whether either intervention is superior.