The hypermobility type of the Ehlers-Danlos Syndrome and Hypermobility Spectrum Disorders
By Valentien Spanhove, PT and PhD researcher @Ghent University
Hypermobility disorders range from asymptomatic joint hypermobility, through Hypermobility Spectrum Disorders (HSD), to the hypermobility type of the Ehlers-Danlos syndrome (hEDS) (Malfait et al. AJMG 2017). While patients with hEDS are characterized by signs of a connective tissue disorder, such as tissue fragility and atrophic scarring, patients with HSD mainly experience complaints limited to the musculoskeletal system. However, in both disorders, joint hypermobility leads to secondary manifestations such as muscle weakness and chronic pain.
Multidirectional Shoulder Instability (MDI) is a common complaint in patients with hEDS or HSD. Muscle strengthening exercises are a main element in the current rehabilitation of patients suffering from joint hypermobility. However, we should consider the impact of these rehabilitation exercises on glenohumeral biomechanics in this patient population. A recent study investigated this issue and called for more insight into designing exercise programs for this fragile population (Spanhove et al. Physiotherapy 2019).
In this study, translations of the humeral head with respect to the acromion were investigated by the use of quantitative ultrasound during 5 isometric exercises. Results showed that an isometric shoulder flexion and an isometric shoulder or elbow extension, leads to a superior translation in the shoulder joint of patients with hEDS/HSD (figure 1). In contrast, significant more inferior translation (sulcus sign) was seen in patients compared to healthy persons when participants were asked to hold a dumbbell of 2 kg in their hand (video 1).
Figure 1: changes in AHD (acromiohumeral distance) during 5 isometric exercises: ER (external rotation), EXT (shoulder extension), FLEX (shoulder flexion), ELB EXT (elbow extension), DUMBBELL (holding a 2kg dumbbell)
Taken these study results into account, we recommend to use isometric shoulder and elbow extension or shoulder flexion exercises in patients with a manifestly inferior shoulder instability (figure 2,3,4). In addition, we discourage the use of weights of 2 kg or more in open chain exercises for patients with hEDS/HSD and MDI, especially in the early phase of rehabilitation, due to the risk of an inferior shoulder (sub)luxation.
Malfait F, Francomano C, Byers P, Belmont J, Berglund B, Black J, et al. The 2017 international classification of the Ehlers-Danlos syndromes. Am J Med Genet C Sem Med Genet 2017;175(1):8–26.
Spanhove V, De Wandele I, Hougs KB, Malfait F, Vanderstukken F, Cools A. The effect of five isometric exercises on glenohumeral translations in healthy subjects and patients with the hypermobility type of the Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorder (HSD) with multidirectional shoulder instability. Physiotherapy (2019), https://doi.org/10.1016/j.physio.2019.06.010