Does obesity affect knee cartilage? A systematic review of magnetic resonance imaging data.

There is increasing evidence for the effect of obesity on knee osteoarthritis (OA), although the association between obesity, particularly body composition, and knee osteoarthritis, using magnetic resonance imaging (MRI) to examine knee structure, has not been examined. We systematically evaluated the evidence for the relationship between obesity and knee cartilage assessed by MRI. We performed an electronic search of MEDLINE and EMBASE up to December 2012. Included studies investigated the association between obesity and the development and/or progression of knee cartilage changes using MRI. The studies were ranked according to their methodological score and best-evidence synthesis was performed to summarize the results Twenty-two studies were identified for inclusion, of which 7 were cross-sectional, 13 were longitudinal and 2 had both cross-sectional and longitudinal components. Seven cross-sectional and eight longitudinal studies were of high quality. Best-evidence synthesis showed consistent, yet limited evidence for a detrimental effect of body mass index (BMI) and fat mass on knee cartilage. This review identified a consistent detrimental effect of obesity, particularly related to elevated BMI and fat mass on cartilage defects. The strength of evidence was limited by the paucity of high-quality cohort studies examining this question. By further examining the mechanisms for these different effects, new strategies can be developed to prevent and treat knee OA.

Vastus medialis cross-sectional area is associated with patella cartilage defects and bone volume in healthy women.

OBJECTIVES: Although vastus medialis and vastus lateralis are important muscular determinants of patellofemoral joint function, it is unclear how these muscles relate to the structure of the patellofemoral joint. The aim of this cross-sectional study was to determine the relationship between the vasti muscles and patella cartilage volume and defects and patella bone volume. METHODS: One hundred and seventy-five women, aged 40-67 years, with no knee pain or clinical lower-limb disease had magnetic resonance imaging (MRI) of their dominant knee. The cross-sectional areas of the distal vastus medialis and lateralis were measured 37.5mm superior to the quadriceps tendon insertion at the proximal pole of the patella. Patella cartilage volume and defects and patella bone volume were measured from these images using validated methods. RESULTS: There was no significant association between the distal vastus medialis cross-sectional area and patella cartilage volume. For every 1mm(2) increase in the distal vastus medialis cross-sectional area, there was an associated increased risk of patella cartilage defects [odds ratio (OR): 1.2; 95% confidence interval (CI) 1.004, 1.5; P=0.05], and an associated increase in patella bone volume (OR: 3.9; 95% CI 2.0, 5.8; P<0.001) after adjustment for potential confounders. There was no significant relationship between vastus lateralis cross-sectional area and measures of patella cartilage or bone. CONCLUSION: An increased cross-sectional area of the distal portion of the vastus medialis muscle is associated with an increased risk of patella cartilage defects, and an increase in patella bone volume among healthy women. Although these results need to be confirmed in longitudinal studies, they suggest that an increase in the distal vastus medialis cross-sectional area is associated with structural change at the patellofemoral joint.

Factors affecting patella cartilage and bone in middle-aged women.

OBJECTIVE: To evaluate the effects of age, physical activity, and body mass index (BMI) on patella cartilage volume and defects and bone volume in middle-aged women without knee pain. METHODS: Magnetic resonance imaging was performed in 176 healthy women, ages 40-67 years, without knee pain to measure patella cartilage and bone volume and patella cartilage defects. The effects of age, physical activity, BMI, smoking, and alcohol were analyzed to determine whether associations existed between these variables and patella cartilage and bone volume and cartilage defects. RESULTS: Patella cartilage volume decreased with age (P = 0.01) and BMI (P = 0.05) after adjusting for age and patella bone volume. Patella bone volume was positively associated with body height in both the univariate and multivariate models. Cartilage defects in the patellofemoral compartment were present in 36.4% of the study population. Age, weight, and BMI were positively associated with the presence of cartilage defects in the multivariate analysis. CONCLUSION: This study demonstrated that although age is positively associated with both patella bone volume and cartilage defects, it is inversely associated with patella cartilage volume in healthy individuals. Moreover, BMI is inversely associated with both patella cartilage volume and patella bone volume in middle-aged women without knee osteoarthritis. Longitudinal studies will be required to determine whether avoiding a high BMI will reduce the risk of developing patellofemoral osteoarthritis.

The relationship between endogenous testosterone, preandrogens, and sex hormone binding globulin and knee joint structure in women at midlife.

OBJECTIVES: To evaluate the relationship between serum testosterone (T), preandrogens and sex hormone binding globulin (SHBG), and the knee structure in middle-aged women without knee pain. METHODS: One hundred and thirty-nine healthy women without knee pain, aged 40 to 67 years, underwent magnetic resonance imaging of their dominant knee to measure tibial and patella cartilage volumes and defects, respective bone area and volume, and bone marrow lesions. The serum level of T, preandrogens, and SHBG were analyzed using linear regression to determine whether associations existed between these hormones and knee structure. RESULTS: Free T and total T showed no association with cartilage volume or bone structures in the knee. SHBG showed a statistically positive association with patella bone volume after adjusting for confounders (P = 0.02). CONCLUSION: Our study suggests there are no associations between serum levels of T or the preandrogens and knee structure in women. The observed positive association between SHBG and patella bone volume may reflect a favorable effect of estrogen exposure on patella bone volume.