GAIT MECHANICS IN PEOPLE WITH CLINICALLY DIAGNOSED HYPERMOBILITY EHLERS DANLOS SYNDROME

Lindsey Nicole Ball, Stephen Duncan, Mary Sheppard, Michael Samaan. University of Kentucky, Lexington, KY. BACKGROUND: Hypermobile Ehlers Danlos Syndrome (hEDS) is a heritable connective tissue disorder that affects muscle function yet the impact of hEDS on gait mechanics is not well understood. Therefore, the purpose of this study was to assess gait mechanics in people with and without hEDS. METHODS: Eleven people with hEDS were matched to 11 asymptomatic controls (CONT). Participants underwent a 3D gait analysis while walking on an instrumented treadmill at a self-selected speed. Between-group differences in sagittal plane hip, knee and ankle joint kinematics and internal moments were evaluated using independent t-tests (Microsoft Excel; p0.05), the hEDS group walked with lower peak hip extensor moments (CONT: -0.98±0.46Nm·kg-1, hEDS: -0.52±0.28Nm·kg-1, p=0.01) and knee flexor moments (CONT: -0.60±0.38Nm·kg-1, hEDS: -0.32±0.17Nm·kg-1, p=0.04) during loading response as well as lower ankle plantarflexor moments (CONT: -1.85±0.65Nm·kg-1, hEDS: -1.34±0.25Nm·kg-1, p=0.03) during terminal stance. Also, 73% of the hEDS participants self-reported a high incidence of hip joint subluxations as well as a moderate level of hip pain (4/10) during walking. CONCLUSIONS: People with hEDS ambulate with similar walking speeds and joint kinematics as healthy controls yet people with hEDS walk lower peak hip extensor, knee flexor, and ankle plantarflexor moments. Our data may indicate an altered gait strategy in hEDS to prevent incidence of hip subluxations and hip pain. Lower peak hip extensor and knee flexor moments during loading response may suggest a compensatory strategy to offload the hip joint in order to prevent hip subluxations and hip pain. Prior work demonstrated that walking with higher foot push-off (i.e. higher plantarflexor force) reduces the anterior hip joint contact force. Reduced plantarflexor moment during terminal stance in the hEDS group may result in higher anterior hip joint contact forces leading to the moderate hip pain reported by the hEDS group during walking (Lewis & Garibay, 2015). Our study results suggest that a rehabilitation program encompassing posterior chain strengthening and gait retraining may lead to optimized gait mechanics and help to reduce incidence of hip subluxation and hip pain during walking in people with hEDS. This research was supported in part by the University of Department of Kinesiology and Health Promotion Graduate Student Research Funding and NIH - K01AG073698-01 (Samaan