High Body Mass Index Is Associated With Increased Diurnal Strains in the Articular Cartilage of the Knee

Abstract

Objective Obesity is an important risk factor for osteoarthritis and is associated with changes in both the biomechanical and inflammatory environments within the joint. However, the relationship between obesity and cartilage deformation is not fully understood. The goal of this study was to determine the effects of body mass index (BMI) on the magnitude of diurnal cartilage strain in the knee. Methods Three-dimensional maps of knee cartilage thickness were developed from 3T magnetic resonance images of asymptomatic age- and sex-matched subjects with normal (18.5–24.9 kg/m2) or high (25–31 kg/m2) BMI. Site-specific magnitudes of diurnal cartilage strain were determined using aligned images recorded at 8:00 AM and 4:00 PM on the same day. Results High BMI individuals had significantly thicker cartilage on the patella and femoral groove than the normal BMI individuals. Diurnal cartilage strains were dependent on location as well as BMI. Subjects with high BMI exhibited significantly higher compressive strain in tibial cartilage than did those with normal BMI. Cartilage thickness decreased significantly on both femoral condyles from the AM to PM time point; however, there was no significant effect of BMI on diurnal cartilage strain in the femur. Conclusions Increased BMI is associated with increased diurnal strains in the articular cartilage of both the medial and lateral compartments of the knee. The increased cartilage strains measured in high BMI individuals may, in part, explain the elevated OA risk associated with obesity or may reflect altered cartilage mechanical properties in subjects with high BMI.

Identifying specific profiles in patients with different degrees of painful knee osteoarthritis based on serological biochemical and mechanistic pain biomarkers

“…3,7,17 Another excluded variable that is commonly used as part of OA diagnosis is the BMI, where elevated BMI has been associated with an elevated OA risk. 48 The biochemical markers not included were CIIM and VICM. VICM has shown to be elevated in the autoimmune-based disorder ankylosing spondylitis (AS) and rheumatoid arthritis (RA) 5 ; however, OA does not share the same autoimmunity as RA and AS.…”

Functional imaging in OA: role of imaging in the evaluation of tissue biomechanics

“…While studies of cartilage mechanics using imaging have noninvasively quantified surface deformation (thickness) and volume changes during loading in patient populations [116–119], results from these studies provide limited information on the three-dimensional deformation occurring in the cartilage interior. Surface shape and volume alone does not account for complex internal mechanical behavior, such as deformation between arbitrary tissue locations, which is known to vary over the thickness of the tissue [47] and locally in the progression of OA [66].…”

“…It is further very challenging to reliably measure small changes in cartilage thickness of large patient populations, noting that the viscoelastic nature of the tissue can mean small deviations in tissue thickness develop even as the patient walks from waiting room to MRI scanner. Care must therefore be placed on the development of rigorous protocols that account for the history of loading in individual patients [119]. These challenges also suggest the importance of looking beyond structural and morphological measures alone to consider functional imaging methods that enhance sensitivity and specificity to disease severity (e.g.…”

Diurnal Variation in Distal Femoral Cartilage Thickness

“…Cartilage thickness on femoral condyles decreased significantly from AM to PM. BMI did not have an influence on diurnal cartilage strain in the femoral cartilage, but did in the tibial cartilage 7 . We investigated the diurnal variation in the thickness of distal femoral cartilage by using US in healthy adults and showed diurnal variations reaching up to 10.6% 8 .…”

“…In another study, Coleman, et al showed that cartilage thickness of the right knee joint decreased from AM to PM in all areas except the patellofemoral groove and lateral femoral condyle, after an average of 8057 steps during daily activities 6 . Finally, Widmyer, et al examined the effect of body mass index (BMI) on diurnal variation of cartilage thickness in the knee joint 7 . Cartilage thickness on femoral condyles decreased significantly from AM to PM.…”