Prevalence, patterns, and risk factors of knee osteoarthritis in Thai monks

Patterns and risk factors of knee osteoarthritis in Asian countries where most people have habitual knee bending activities remain unclear. The objective of this study was to evaluate the prevalence, patterns, and risk factors of knee osteoarthritis in Thai monks. The study was a cross-sectional survey of monks who lived in temples in southern Thailand. Investigations included history, physical examination, and radiographic evaluation including weight-bearing antero-posterior, lateral, and skyline views. There were 261 monks from 85 temples included in this study. The overall prevalence of radiographic knee osteoarthritis was 59.4%, with 29.6% having symptomatic radiographic knee osteoarthritis. The patterns of involvement were isolated tibiofemoral compartment (7.7%), isolated patellofemoral compartment (18.8%), and combined (32.9%). Obesity (OR 5.6, 95% CI; 1.6–19.8), age equal to or more than 60years (OR 3.0, 95% CI; 1.5–6.0), and age at ordainment equal to or more than 46years (OR 2.2, 95% CI; 1.1–4.6) were associated with risk of developing radiographic knee osteoarthritis. Obesity (OR 17.9, 95% CI; 2.4–132.1) and current smoking (OR 7.7, 95% CI; 2.4–24.3) were associated with symptomatic radiographic knee osteoarthritis. Severity of involvement was associated with obesity (OR 12.0, 95% CI; 2.3–60.9), older age (OR 3.8, 95% CI; 1.3–5.1), and older age at ordainment (OR 2.8, 95% CI; 1.3–6.1). The prevalence of radiographic knee osteoarthritis with patellofemoral involvement in Thai monks is high and is more common among the elderly, those who were older at ordainment, and obese subgroups. Each pattern of knee osteoarthritis might have a different pathomechanism in the development of osteoarthritis.