Effects of Bariatric Surgery on Knee Articular Cartilage and Osteoarthritis Symptoms—A 12‐Month Follow‐Up Using T2 Relaxation Time and WOMAC Osteoarthritis Index

Abstract

BackgroundObesity is a significant risk factor for osteoarthritis (OA). The most effective treatment for morbid obesity is bariatric surgery.PurposeTo study the effects of potential surgically induced weight loss on knee articular cartilage and OA symptoms of obese patients over a 12‐month follow‐up.Study TypeProspective longitudinal cohort study.Subjects45 obese patients (38 female, BMI = 42.3 ± 6.5 kg/m2) who underwent gastric bypass (intervention group), and 46 age‐matched conservative‐care controls (37 female, BMI = 39.8 ± 4.6 kg/m2).Field Strength/SequenceMultiecho spin echo sequence at 3 T.AssessmentKnee cartilage T2 measurements and WOMAC Indices were measured presurgery and after 12 months. The intervention group was split into successful (≥20% total weight loss (TWL)) and unsuccessful (<20% TWL) weight loss groups. T2 and WOMAC indices were also measured in controls at baseline and after 12 months. Changes among the three groups were analyzed.Statistical TestsAnalysis of variance (significance level 0.05).ResultsTwenty‐six (58%) intervention patients achieved ≥20% TWL. The <20% TWL group demonstrated significantly more T2 reduction in the deep lateral femur over 12 months compared with the ≥20% TWL group (−3.83 ± 8.18 msec vs. 2.47 ± 6.54 msec, respectively), whereas no significant differences were observed on the medial femoral compartment (P = 0.385, P = 0.551, and P = 0.511 for bulk, superficial and deep regions, respectively). Changes in WOMAC indices over 12 months were significantly greater in the ≥20% TWL group compared with controls. In the <20% TWL group, pain significantly improved over 12 months compared with controls, while stiffness and function changes were not statistically significant (P = 0.063 and P = 0.051, respectively).Data ConclusionCartilage matrix, measured by T2, showed improvement on lateral femoral cartilage with <20% TWL compared with ≥20% TWL. Bariatric surgery provided significant improvements in knee symptoms with ≥20% TWL compared with conservative WL. This effect is also seen to some extent with <20% TWL compared with conservative WL.Level of Evidence2Technical EfficacyStage 4