Obesity related measurements and joint space width in patients with knee osteoarthritis

Background The aim of this study is to analyze the relationship between body mass index and obesity related measurements and tibiofemoral joint space which have been the principal method of radiographic evaluation in progression and therapeutic trials of knee osteoarthritis. Methods Fifty-five female patients with the diagnosis of osteoarthritis in knees according to the criteria of American College of Rheumatology in knees were included in the study. The mean age of patients was 57,42 +/- 8,60(SD) years with a range of 42-77. Medial and lateral compartment joint space widths were measured on antero-posterior knee radiography. Body mass index, triceps, biceps, subscapular and suprailiac skinfold thickness, waist and hip circumference were measured. Body composition was determined by dual energy X-ray absorpsiometry (DEXA) (Norland XR 46) and total lean mass (g), total fat mass (g), trunk lean mass, trunk fat mass, abdomen lean mass, abdomen fat mass measurements were recorded. Results Patients with body mass index>30 were accepted as obese patients. According to these criteria 33 of the 55 patients were obese. Tibial medial compartment and tibial lateral compartment measurements of obese patients were significantly lower than nonobese patients (p=0,000, p=0,003 respectively). Body mass index was correlated with total lean mass, total fat mass, trunk fat mass, abdominal fat mass, leg fat mass. Tibial medial compartment and tibial lateral compartment space measurements were negatively correlated with body mass index. Conclusion: Our results revealed significant difference in both medial and lateral joint spaces of obese and nonobese patients with knee osteoarthritis. Medial and lateral joint spaces of obese patients were narrower than nonobese osteoarthritis patients. The more body mass index had the patients the narrower joint space they had displayed. However body composition analysis and obesity related measurements did not show additional correlation with tibial compartment measurement.