The impact of Joint Hypermobility Syndrome in adults: A quantitative exploration of neuromuscular impairments, activity limitations and participation restrictions

Abstract: Introduction: Joint hypermobility syndrome (JHS) is a heritable connective tissue disorder associated with multiple joint laxity and pain. JHS is severe and disabling condition with a prevalence reaching 55% of patients attended physiotherapy with musculoskeletal symptoms. However, the literature is limited in quantity and quality to support the assessment and management strategies for people with JHS. Therefore, impairment, activity and participation were explored to identify the underlying problems. Methods: A cross-section design was employed to compare a group of adults with JHS against a matched control group. Neuromuscular impairments were explored through five domains: 1) pain intensity in the lower-limb joints was measured using visual analogue scales. 2) Achilles tendon stiffness was measured using the diagnostic ultrasound with strain-gauge myometer. 3) the plantar flexors strength was measured using the strain-gauge myometer. 4) knee proprioception was explored using the angle reproduction test. 5) gastrocnemius medius (GM) elasticity was quantified using the sonoelastography (SEG). Regarding the activity domain, both gait and vertical jump were analysed in terms of spatiotemporal, kinematics and kinetics using the Qualisys motion capture system, synchronised with the Kistler platform. The participation domain was assessed using the 12-item Short Form Health Survey (SF-12) and the Bristol Impact of Hypermobility questionnaire (BIoH). Additionally, the feasibility of the SEG was explored, and the intra-rater reliabilities for examining the Achilles tendon stiffness and gait kinematics were determined. Statistical Package for Social Sciences (SPSS) was used to conduct the statistical analysis. Results: The JHS group included 29 women and two men aged 38.52 ± 14.14 years (mean ± SD), while the control group included 29 women and two men aged 39.06 ± 12.43 years (mean ± SD). Various statistically significant differences were identified in the JHS group when compared to the control group, including increased pain intensity (all p ≤ 0.001), reduced Achilles tendon stiffness (p = 0.03), reduced plantar flexors strength (p = 0.01) and reduced non-dominant knee proprioception (p range 0.001 – 0.04). The gait and jump kinematics in the JHS group were mostly comparable to the control (p ≥ 0.05), with statistically significant reductions in moments (p ranged from 0.001 - 0.04) and power generation and absorption (p ranged from 0.001- 0.04) in the JHS group. Significant reductions in the participation level were evidenced in the JHS group, obtained from SF-12 (p ranged from 0.001 - 0.002), with significant impact from JHS (211.51 ± 39.28)/360 (mean ± standard deviation) obtained from the BIoH. Sonoelastography seems a feasible tool in terms of training, examination time, patient tolerance, and image analysis. High intra-rater reliability was demonstrated for examining the Achilles tendon stiffness (ICC ranged from 0.981 – 0.984), and moderate-high intra-rater reliability was demonstrated for examining gait kinematics (ICC ranged from 0.625 – 0.996). Conclusion: JHS has a multi-dimensional impact, causing neuromuscular impairment, activity limitations and participation restrictions. Assessment strategies should consider this multi-dimensional impact of the condition, and management strategies should be multi-disciplinary, aiming to target the problems identified in the current study. Key words: Joint hypermobility syndrome, impairment, activity, participation.