Incidence of primary osteoarthritis knee below 40 years of age and its etiological factors: OPD survey of 200 knee pain patients

Introduction: For decades, knee OA had been viewed as a disease mostly affecting older population, consequently, only few population-based studies have examined the frequency and characteristics of OA knee in persons under the age of 40 years leading to dearth of literature over this subject matter. Recent evidence however, documents increased incidence of two key risk factors for knee OA – traumatic knee injury and obesity, particularly in the young. Studies have shown that mean age of onset of osteoarthritis knee has decreased over couple of decades and projected incidence of the disease in young is on the rise. Materials and Methods: Patients of either sex coming to the OPD of the Department of Orthopaedics with chief complaint of knee pain were assessed as per the preformed and pretested questionnaire and subjected to AP view of both knee in standing position until 200 such cases with age ? 40yrs were separated. The cases were assessed as per Kellgren Lawrence grading. The patients were also assessed for height, weight, BMI and other parameters. Cases were selected carefully after excluding the subjects as per the adopted exclusion criterion. Results: After survey of 200 knee pain patients below 40 years of age, over a period of one and a half years, incidence of primary osteoarthritis knee on the radiological basis was found to be 6.54%. Mean age of 200 subjects were 34.7 years with female: male ratio being 6:1(p=0.004). 82.1% cases of OA had BMI >24.9kg/m2 (p=0.004) whereas 80 females cases had BMI>24.9kg/m2 (p=0.007). 53.5% cases had predominantly sitting/ squatting /kneeling as household habits (p=0.02). 67.8% cases were of medium activity group on the basis of their occupation while 57.1% (p=0.05) of cases had history of OA knees in the first degree relatives. Conclusion: The incidence of OA knee in the young is increasing. Knowing the risk factors and disease volume in younger age groups would allow primary prevention of OA to be implemented in young adulthood to curtail the emergence of radiographically-defined OA at the mid-life and also prevent disabilities saving the healthcare system from the tremendous economic burden of the disease.