Knee Osteoarthritis in Farmers: Occupational Risk, Functional Burden and Comparative Review of Patient Reported and Performance Based Assessment Scales
Abstract
Background: Knee osteoarthritis (KOA) is a major cause of pain, functional limitation and disability. Farmers represent an important occupational population because agricultural work commonly involves kneeling, squatting, prolonged standing and walking, lifting, carrying and repetitive knee loading. Epidemiological evidence supports an association between physically demanding agricultural work and KOA, with particularly consistent evidence for cumulative kneeling or squatting exposure. Objective: To review the occupational relationship between farming and KOA and compare commonly used clinical, patient-reported and performance-based assessment instruments, with emphasis on the Lower Extremity Functional Scale (LEFS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), Lequesne index, pain scales, Kellgren–Lawrence radiographic grading and OARSI performance-based measures. Methods: A structured narrative review was prepared using peer-reviewed literature identified through PubMed/MEDLINE and major biomedical literature sources, supplemented by established measurement and clinical guidance documents. Literature concerning occupational knee loading, farming, kneeling and squatting, KOA, and measurement properties of KOA outcome instruments was critically synthesized. Particular attention was given to validity, reliability, responsiveness, interpretability, feasibility and applicability to agricultural workers. Conclusion: Farming is an important occupational context associated with increased KOA risk, although it should not be regarded as a sole cause. No single outcome instrument captures structural disease, pain, function, performance and occupational participation simultaneously. A multidimensional assessment combining a validated patient-reported measure such as LEFS, WOMAC, KOOS or OKS with pain assessment, appropriate structural assessment and objective performance testing can provide a more complete picture of KOA in farmers.