Epidemiology and Risk Factors of Patellofemoral Osteoarthritis in Adults: A Population-Based Study in Southern Thailand
Boonsin Tangtrakulwanich MD*, Poramet Suwanno MD*
Affiliation : * Department of Orthopaedic Surgery and Physical Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
Objective : Study the epidemiology and factors associated with patellofemoral osteoarthritis.
Material and Method: A population-based survey was undertaken in Songkhla, a province in the southern part of Thailand.
Residents aged 40 years and older were sampled using primary care units as a primary sampling frame, stratified by age
and sex. All participants were taken to a private clinic for an interview and radiographic examination, including anterior-
posterior, lateral and skyline views of both knees. Types and severities of involvement in each compartment were graded
by one musculoskeletal radiologist.
Results : Of the eligible 694 subjects, 576 (81.4%) agreed to participate in the present study. The prevalence of radiographic
patellofemoral osteoarthritis was 37.9%, of which 96% was bilateral involvement. Isolated patellofemoral osteoarthritis
was the most common pattern in males (18.0%), while the combined pattern (involvement of both tibiofemoral and
patellofemoral compartments) was the most common pattern in females (31.2%). Elderly (OR = 8.8, 95% CI: 5.1-15.3) and
obese (OR = 7.9, 95% CI: 3.3-15.3) were independent risk factors predicting patellofemoral osteoarthritis.
Conclusion : There was a high prevalence of patellofemoral osteoarthritis among Thais over 40 years of age, associated
with age and obesity.
Keywords : Epidemiology, Risk factors, Patellofemoral osteoarthritis
