People With Marfan Syndrome Ambulate With Altered Joint Mechanics

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by mutations in the fibrillin-1gene. MFS is associated with muscle dysfunction, severe joint pain, and a high incidence of osteoarthritis (OA). The impact of MFS on gait mechanics and possible association with joint degeneration has yet to be investigated. PURPOSE: To assess the effects of MFS on lower extremity joint kinematics and kinetics during walking. METHODS: 18 people with MFS (16F; age = 39.3 ± 11.3 yrs; body mass index (BMI) = 25.8 ± 5.7 kg/m2) and 18 sex and BMI-matched healthy, asymptomatic controls (16F; age = 26.4 ± 7.5 yrs; BMI = 23.7 ± 3.9 kg/m2) underwent 3D gait analysis while walking at a fixed speed of 1.35 m/s, the average level-ground walking speed of females and males. Between-group differences in sagittal plane hip, knee, and ankle joint kinematics and kinetics were assessed using an analysis of covariance, adjusting for age, with p < 0.05 used for statistical significance. RESULTS: The MFS group was significantly older than the control group (p < 0.01). The MFS cohort ambulated with a higher peak hip flexion angle (p = 0.02), peak knee flexion angle during loading response (p < 0.01), knee excursion (p < 0.001), peak ankle dorsiflexion angle (p < 0.01), and ankle range of motion (p = 0.04). The MFS cohort also exhibited a significantly higher hip extensor moment impulse (p = 0.02) and impulse duration (p = 0.04), higher knee extensor moment (KEM) impulse during the 1st half of stance (p = 0.03), higher peak KEM during the 2nd half of stance (p = 0.01), and a shorter KEM duration during the 2nd half of stance (p = 0.04). The MFS group exhibited a significantly lower ankle dorsiflexion moment (p < 0.01) and moment impulse (p < 0.01) as well as a longer ankle plantarflexor moment duration (p = 0.01). CONCLUSION: These results suggest that people with MFS walk with altered hip, knee, and ankle joint mechanics. More specifically, people with MFS ambulate with a more flexed lower extremity, which places a higher demand on the hip and knee extensor musculature to maintain an upright position during walking. These altered lower extremity joint mechanics may explain the higher incidence of OA and joint pain in the MFS population, yet further evaluation to understand a causative link between joint mechanics and joint degeneration in the MFS population is needed. The Marfan Foundation, NIH (KL2-TR001996, K01-AG073698, & K01-HL149984)