Background: Knee osteoarthritis (OA) has functional association with pain, reduced mobility and problems in main domain of activity. The objective of this study was to find out the relationship between the grades of knee OA according to Kellgren and Lawrence system and the functional limitation in the daily activities of the elderly patients using WOMAC Questionnaire.

Patients and Methods: This cross-sectional study was conducted on 160 subjects aged ≥ 50 years, out of which, 131 (82%) of the patients were female and 29 (18%) were male. All participants were diagnosed with knee OA at an orthopedic clinic using the Kellgren and the Lawrence system for classification of Osteoarthritis of the knee with no history of knee joint surgery. Outcome indices were functional limitations in 17 living activities obtained from a WOMAC questionnaire. 

Results: A significant correlation was found between increase in knee OA stages in x-rays and the severity of limitation in physical function (p value <0.01). The results indicated that functional limitation was proportional to the increase in Osteoarthritis x-ray grades. Greatest limitation of movement was found in descending stairs, where the least scores with mild to moderate OA (1.41 ± 0.76; P < 0.01) became (3.78 ± 0.47; P < 0.01) as the X-ray grade increases to IV. 

Conclusion: Functional disability is the principle reason for which patients with chronic knee pain seek medical treatment. The findings of our study suggest that patients with greater disability and functional limitations in their daily activities have advanced knee OA grades III to IV according to the kellgren- Lawerence scale.