Weight loss in obese people has structure-modifying effects on medial but not on lateral knee articular cartilage

Abstract

Background Obesity is an important risk factor for knee osteoarthritis (OA), Weight loss can reduce the symptoms of knee OA. No prospective studies assessing the impact of weight loss on knee cartilage structure and composition have been performed. Objectives To assess the impact of weight loss on knee cartilage thickness and composition. Methods 111 obese adults were recruited from either laparoscopic adjustable gastric banding or exercise and diet weight loss programmes from two tertiary centres. MRI was performed at baseline and 12-month follow-up to assess cartilage thickness. 78 eligible subjects also underwent delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), an estimate of proteoglycan content. The associations between cartilage outcomes (cartilage thickness and dGEMRIC index) and weight loss were adjusted for age, gender, body mass index (BMI) and presence of clinical knee OA. Results Mean age was 51.7±11.8 years and mean BMI was 36.6±5.8 kg/m 2 ; 32% had clinical knee OA. Mean weight loss was 9.3±11.9%. Percentage weight loss was negatively associated with cartilage thickness loss in the medial femoral compartment in multiple regression analysis (β=0.006, r 2 =0.19, p=0.029). This association was not detected in the lateral compartment (r 2 =0.12, p=0.745). Percentage weight loss was associated with an increase in medial dGEMRIC in multiple regression analysis (β=3.9, r 2 =0.26; p=0.008) but not the lateral compartment (r 2 =0.14, p=0.34). For every 10% weight loss there was a gain in the medial dGEMRIC index of 39 ms (r 2 =0.28; p=0.014). The lowest weight loss cut-off associated with reduced medial femoral cartilage thickness loss and improved medial dGEMRIC index was 7%. Conclusions Weight loss is associated with improvements in the quality (increased proteoglycan content) and quantity (reduced cartilage thickness losses) of medial articular cartilage. This was not observed in the lateral compartment. This could ultimately lead to a reduced need for total joint replacements and is thus a fi nding with important public health implications.

Prevention of Incident Knee Osteoarthritis by Moderate Weight Loss in Overweight and Obese Females

“…Previously, 1 study reported a preventive effect of weight loss on cartilage thickness of the knee (18). However, this was an observational study without validated clinical or radiologic OA outcomes, making the results less applicable in clinical practice.…”

“…In trials among subjects with and without established knee OA, weight loss was shown to have advantageous structure-modifying, systemic, and clinical effects (15)(16)(17)(18)(19)(20)(21). In a systematic review on the effects of weight loss on knee OA patients, a weight loss of at least 5% of body weight was indicated for symptomatic relief (22).…”

Is Weight Loss Associated with Less Progression of Changes in Knee Articular Cartilage among Obese and Overweight Patients as Assessed with MR Imaging over 48 Months? Data from the Osteoarthritis Initiative

“…Another study showed that obesity increases the risk for progression in especially varus-aligned extremities (47). Previous studies have shown that the medial compartment in general is exposed to higher rates of cartilage loss in people with osteoarthritis, which could be attributed to a greater proportion of ground reaction forces by the medial tibiofemoral compartment even in normally aligned knees (40,48).…”

“…Similarly, previously investigators reported that the percentage of weight loss is significantly associated with change in cartilage volume (19) and composition (40) of the medial tibia. However, in the previous studies, participants were followed up within a very inhomogeneous and shorter period of time, and the study cohorts with different degrees of weight loss, the group with a substantial amount of weight loss (.10% weight loss) showed significantly lower odds of cartilage degeneration when compared with the stable-weight reference group, whereas the odds were not significantly lower when we compared the 5%-10% weight loss group with the stable-weight group.…”

An update on the treatment of osteoarthritis in obese patients

“…[6] On the other hand, the effect of weight loss in the structural progression of knee OA is still not established, and different studies have reached contrary conclusions. [7,8] A dose-response relationship between the extent of percentage change in body weight and improvement in joint symptoms has been demonstrated, with more robust effects with at least 10% reduction in body weight. [9] A reasonable time frame to achieve this goal is 6 months, with a weight reduction rate of 250-500 or 500-1000 g/week in persons with a BMI > 35 kg/m 2 .…”