Purpose: Osteoarthritis (OA) is a leading cause of disability, affecting 60-70% of people aged ≥60 years. Community-based prevalence estimates of OA in Nigeria are not readily available for referencing. This study investigated the prevalence and pattern of knee OA in Igbo-Ora, a rural community in Southwestern Nigeria. Methods: A total of 1044 adults (487 males, 557 females) aged ≥ 40 years in Igbo-Ora were recruited into this door-to-door survey through multi-stage cluster sampling. Knee OA was diagnosed using the American College of Rheumatology (ACR) clinical criteria. Knee OA severity was assessed using the Lequesne Algofunctional Index and interference with role performance was rated by participants who met the ACR criteria. Plain radiographs of a multiphase sample of 15 participants with Knee OA were taken. Data was analysed using percentages and Chi square. Results: Two hundred and five (119 females, 86 males) out of the 1044 participants fulfilled the ACR criteria, giving a point prevalence of symptomatic knee OA of 19.6%. The prevalence of knee OA was 21.4% among the females and 17.5% among the males, giving a female bias in the ratio of 1.2:1. Prevalence increased and was significantly associated (P\u3c 0.001) with age. Most participants (98.5%) had moderate-extremely severe disease and knee OA interfered with role performance in 90.2% of participants. All radiographs showed signs consistent with OA. Conclusion: One out of every five adults aged ≥40 years in this Nigerian rural community has symptomatic knee OA, with a female preponderance in the ratio of 1.2:1
