Background Obesity is a major risk factor for osteoarthritis of the knee. However, the fat and muscle have different effects on the pathogenesis of the disease.

Objectives The purpose of this study was to examine the relationship between body composition and knee structure especially cartilage defects, osteophytes and bone marrow lesions (BMLS).

Methods This is a cross-sectional study including patients with primary knee OA. Demographics, clinical and laboratory characteristics for the disease were collected. All patients underwent magnetic resonance imaging (MRI) of the dominant knee. The results were interpreted according to WORMS system [1] (whole organ magnetic resonance imaging score). The body composition was measured using DEXA (dual energy X-ray absorptiometry). The regression was used to assess the association of body mass (fat mass and musculoskeletal mass) with MRI data in particular: cartilage defects, osteophytes and BMLs.

Results Twenty patients with osteoarthritis of the knee were included in the study, 85% were female. The mean age was 59.3±10.3 years. The patients had a mean body mass index 30.1±4.7 kg/ m². The functional discomfort of patients assessed by the WOMAC averaged 38.3±11.3. The mean of total fat mass was 32.6±10.8 kg. The mean of musculoskeletal mass was 15.8±2.5 kg. The fat mass was associated with increased cartilage defects in univariate analysis (p=0.04). However, musculoskeletal mass was not significantly associated with cartilage defects or osteophytes or BMLs.

Conclusions This study suggests that there is an association between fat mass and increased cartilage defects, however we do not find an association between body composition in particular musculoskeletal mass and knee injuries in OA. Further studies are needed to confirm these results.

References

1. OsteoArthritis and Cartilage (2004) 12, 177–190

Disclosure of Interest None declared