Ab1186 body Mass Index Effects Quadriceps Muscle Architectural Characteristics in Patients With Knee Osteoarthritis

Abstract

BackgroundSufficient lower extremity muscle mass is necessary for performing functional tasks. It is well known that body mass index (BMI) adversely effect knee cartilage health but in knees with osteoarthritis (OA) it is still unclear how BMI level effect knee muscle architectural characteristics.ObjectivesThe aim of this study was to investigate effect of body mass index (BMI) level on quadriceps muscle architecture in patients with knee OA and healthy controls.MethodsNineteen patients with OA (mean age= 50.58±4.56 years, mean BMI=28.29±2.51 kg/m2,) and twenty healthy controls (mean age= 48.35±2.83 years, mean BMI=26.76±4.88 kg/m2) were included in the study. Rectus Femoris (RF), Vastus Medialis (VM) and Vastus Lateralis (VL) muscles thickness and pennation angle were evaluated using B-Mode ultrasonography (Esaote MyLab X8 eXP Ultrasound System, Florence, Italy). Ultrasound images were analyzed offline using an image analysis software (Image J, National Institutes of Health, Bethesda, MD, USA) program. When investigating the changes in muscle architecture by group, the effect of BMI was adjusted using covariance analysis (ANCOVA) tests.ResultsThere were no differences between age (p=0.073) and BMI (p=0.10) in both groups. Interaction between groupXBMI represented in Table 1. Control group had higher RF muscle thickness, RF pennation angle, VM muscle thickness, VM pennation angle and VL muscle thickness than OA group. There was significant effect of BMI on VM and VL muscle thickness.ConclusionPatients with knee osteoarthritis has lower quadriceps muscle thickness and pennation angle than matched healthy controls and BMI was an important factor effecting muscle characteristics. The decrease in VM and VL muscle thickness were associated with increased BMI in knee OA group. These findings highlight the need of body weight control in order to restore muscle thickness in knee OA patients.References[1]Aily JB, de Noronha M, de Almeida AC, et al. Evaluation of vastus lateralis architecture and strength of knee extensors in middle-aged and older individuals with knee osteoarthritis. Clin Rheumatol. 2019;38(9):2603-2611.[2]Keng A, Sayre EC, Guermazi A, Nicolaou S, Esdaile JM, Thorne A, Singer J, Kopec JA, Cibere J. Association of body mass index with knee cartilage damage in an asymptomatic population-based study. BMC Musculoskelet Disord. 2017 Dec 8;18(1):517. doi: 10.1186/s12891-017-1884-7.Table 1.Muscle architectural characteristics of the groups and interaction between group and BMI.ParametersOA Group (n=19, 27 knees)mean (SD)Healthy Group (n=20, 39 knees)mean (SD)Group effectpBMI effectpRFMuscle thickness (cm)1.78±0.351.99±0.300.0060.153Pennation angle (°)11.76±3.6313.71±2.290.0080.444VMMuscle thickness (cm)1.6±0.371.88±0.28<0.0010.032*Pennation angle (°)10.08±3.6213.05±2.7<0.0010.889VLMuscle thickness (cm)1.84±0.52.05±0.330.0140.032*Pennation angle (°)15.85± 2.9615.71±2.830.8990.770OA: Osteoarthritis, RF: Rektus Femoris, VM: Vastus Medialis, VL: Vastus Lateralis, SD: Standard Deviation*p<0.05 Significant effect of BMI on groups.Acknowledgements:NIL.Disclosure of InterestsNone Declared.