Epidemiological Trends and Burden of Osteoarthritis of the Hip and Knee in Middle-Aged Adults Across South South Nigeria: A Cross-Sectional Multicentre Study

Osteoarthritis of the hip and knee is a leading cause of musculoskeletal disability in middle-aged and older adults, with an escalating prevalence linked to rising obesity rates, population ageing, and post-traumatic joint disease. Despite its growing impact, population-level epidemiological data on osteoarthritis in South South Nigeria are limited. This cross-sectional multicentre study estimates the prevalence and describes the risk factor profile of symptomatic hip and knee osteoarthritis among adults aged 40 to 70 years in Rivers, Delta, and Edo States. A standardised questionnaire incorporating the validated OARSI clinical criteria, the Oxford Hip Score, and the KOOS (Knee Injury and Osteoarthritis Outcome Score) will be administered to 1,200 patients at three tertiary hospitals and six community health centres. Radiographic grading (Kellgren-Lawrence classification) will be performed where available. Logistic regression will identify significant risk factors including BMI, occupation, prior joint injury, and co-existing hypertension. The study fills a critical epidemiological data gap and provides a population baseline for osteoarthritis burden in the South South zone. Findings will be disseminated to state ministries of health and contribute to national non-communicable disease prevalence reporting. Keywords: osteoarthritis, prevalence, South South Nigeria, KOOS, Kellgren-Lawrence classification.