Unilateral versus bilateral primary knee osteoarthritis: Relation to the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), C-reactive protein and radiological assessment in Egyptian patients

Abstract

Aim of the workTo study the differences between unilateral and bilateral knee osteoarthritis (KOA) patients in relation to the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), C-reactive protein (CRP) and radiological assessment. Patients and methodsThe study included 80 primary KOA patients subgrouped into those with unilateral or bilateral condition according to the X-ray. WOMAC scale and body mass index (BMI), waist (WC) and thigh (TC) circumferences were measured. The CRP and lipid profile were evaluated and plain X-ray knees assessed by Kellgren and Lawerence (KL) grade. ResultsPatients mean age was 50 ± 9.8 years, disease duration 4 ± 3 years and were 61 females and 19 males. Mean BMI was 32 ± 6.6, WC 96 ± 20 cm, TC 56 ± 11.5 cm, WOMAC 43 ± 14 and KL grade 2 ± 0.9. Unilateral knee was detected in 28 (35%) and was bilateral in 52 (65%) patients. Highest pain was detected in female patients on using stairs and was significant on weight-bearing (p = 0.004), but going downstairs and the KL grade were significantly more in males (p = 0.004 and p = 0.03 respectively). The WOMAC pain subscale items and KL grading were significantly increased in patients with bilateral KOA. The WOMAC significantly correlated with the BMI, WC, TC, lipid profile and KL grade (p < 0.0001 for all). On regression, only the disease duration and cholesterol levels were predictors of WOMAC score (β = 0.2, p = 0.04 and β = 0.29, p = 0.03 respectively). ConclusionsPain on weight bearing in females and bending activities especially going downstairs (in males) appears early with primary KOA. Bilateral involvement is more painful with more radiographic severity.