The Correlation Between Clinical and Radiological Severity of Primary Knee Osteoarthritis at the Kenyatta National Hospital

Abstract

Background: Primary osteoarthritis is the main cause of knee pain in patients seen at the KNH arthroplasty outpatient clinic. Appropriate management of knee osteoarthritis is based on both clinical and radiological findings. However, there is discordance on how knee pain, deformity and functional impairment can be correlated. This would aid in informing management plans. Currently, there is no laid-out protocol on how to manage the different patients with primary knee OA at KNH. This study is aimed at establishing the correlation between the clinical and radiological severity of knee OA which would aid in developing a management protocol for such patients. Broad objective: To correlate the radiological grading of primary knee OA with the severity of pain, stiffness, and degree of deformity of the knee Study design: A prospective cross-sectional study Study site: The Kenyatta national hospital arthroplasty outpatient clinic. Methodology: Patients attending the arthroplasty outpatient clinic with a diagnosis of primary knee OA at Kenyatta National Hospital (KNH) will be included in this study. The American College of Rheumatology (ACR) clinical criteria will be used in the diagnosis of primary knee OA. Also recorded will be the patient demographic data including age, sex and body mass index. Only one knee will be considered for evaluation which will be the index knee and in instances of bilateral knee joint pains, the most painful joint will be recruited. Whereas if the magnitude of the knee pain is equal according to the patient, knee selection for the study will be done randomly and considered the index knee. The Kellgren and Lawrence scale will be used in grading the anteroposterior and lateral views radiographs of weight bearing knee. On the other hand, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) will be used in grading pain, stiffness, and degree of disability of the index knee. A sample size set at 70 will be determined using Fischer et al. formula. Data was analyzed using SPSS vs. 25. xii Results: The study involved a sample of 70 patients with knee OA seen at KNH. The mean age was 61.49 ±11.09 years. A majority of the participants 35.7% (N = 25) were aged between 61 – 70 years, females patients 81.4% (N = 57), had the right knee affected 55.7% (N = 39), had mechanical knee pain 98.6% (N = 69), reported morning stiffness 65.7% (N = 46), had knee crepitus 82.9% (N = 58), had bonny tenderness 61.4% (N = 43), had bonny enlargement 51.4% (N = 36), and had palpable knee warmth 85.7% (N = 60). On WOMAC, the total score for the pain rating had a minimum of 2 while the highest score was 17 and a mean of 8.33± 3.62. The stiffness total score ranged from 0 - 7 with a mean of 3.19 (SD= 2.29). For the difficulty in completing activities of daily living, the score ranged from 6 to 63 with a mean of 30.39 (SD = 11.89). Overall, the minimum WOMAC score ranged from 11 through 86 with a mean of 41.91 (SD = 15.75). On KL classification, the three radiologist agreed that 35.7% (N = 25) participants had extreme OA, 30.0% (N = 21) had severe OA, 15.7% (N = 11) had moderate OA, 11.4% (N = 8) had mild OA while 7.1% (N = 5) had no OA. Cohen Kappa interrater reliability test indicated there was no agreement between the WOMAC and KL scale in grading the severity of knee OA (k = - 0.030). Conclusion: There was no agreement between the scoring of OA using the WOMAC in comparison to rating based on KL classification. Based on the primary findings, this study recommends the use of more than one scale in making the diagnosis for OA