Electromyographic Muscle Activity and Three‐Dimensional Scapular Kinematics in Patients With Multidirectional Shoulder Instability: A Study in the Hypermobile Type of the Ehlers‐Danlos Syndrome and the Hypermobility Spectrum Disorders

Abstract

Objective To investigate differences in electromyography (EMG), muscle activity, and scapular kinematics during elevation in the scapular plane between healthy controls, participants with multidirectional shoulder laxity (MDL), and patients with multidirectional shoulder instability (MDI) who are diagnosed with hypermobile Ehlers‐Danlos syndrome (hEDS) or hypermobility spectrum disorder (HSD). Methods Twenty‐seven women with hEDS/HSD and MDI, 27 female healthy control subjects, and 28 female subjects with MDL participated in this study. Scapular 3‐dimensional kinematic data were obtained using 8 Oqus Qualisys cameras. Simultaneously, surface EMG was used to measure muscle activity of the upper, middle, and lower trapezius, infraspinatus, latissimus dorsi, serratus anterior, posterior deltoid, and pectoralis major during arm elevation in the scapular plane. Group differences were assessed using statistical parametric mapping. Results Regarding scapular kinematics, significantly less upward rotation was observed in hEDS/HSD patients with MDI compared to both healthy controls and MDL subjects. Significantly less posterior tilt was seen in hEDS/HSD patients compared to MDL subjects. Furthermore, significantly higher EMG activity of the infraspinatus, middle trapezius, and posterior deltoid was found in hEDS/HSD patients with MDI. Conclusion hEDS/HSD patients with MDI demonstrate altered scapular kinematics and increased EMG muscle activity compared to subjects without MDI. These findings could serve as a stepping stone for future research regarding treatment strategies in patients whose conditions belong to the hypermobility spectrum.

Multidirectional instability of the shoulder: a systematic review with a novel classification

“…When the history of presenting complaint was analyzed in this review, patients were deemed symptomatic when they presented with either pain, instability and/or subluxation, and/or dislocation in 45 studies ( 1 , 13 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ).…”

“…Twenty-four studies explicitly excluded voluntary dislocators ( 1 , 19 , 21 , 22 , 23 , 28 , 36 , 37 , 42 , 43 , 44 , 45 , 48 , 50 , 55 , 59 , 61 , 62 , 67 , 68 , 69 , 70 , 71 , 73 ), while the rest of the studies did not.…”

One-year effectiveness of high-load compared with low-load strengthening exercise on self-reported function in patients with hypermobile shoulders: a secondary analysis from a randomised controlled trial

“…Acknowledging the fact that patients with HSD and shoulder symptoms have different clinical profiles (eg, regarding symptoms and coexistent shoulder diagnoses),25 the difference in exercise programmes may be of importance when choosing which exercises the patient should use. There is moderate evidence for altered muscle activity and altered humeral and scapular kinematics in individuals with multidirectional instability with and without HSD that could be addressed in the rehabilitation 42 43. Closed kinetic chain shoulder abduction exercises may enable full range of motion earlier in rehabilitation programmes, and open kinetic chain shoulder abduction exercises are required to facilitate the stabilising role of the rotator cuff and axioscapular muscles through daily function 44.…”

Short-term effectiveness of high-load compared with low-load strengthening exercise on self-reported function in patients with hypermobile shoulders: a randomised controlled trial

“…Remarkably, four out of five people with HSD experience symptoms in the shoulder joint3 9–11 with profound consequences in daily life 4 5. Recent studies have reported altered scapular kinematics, imbalanced electromyographic scapular muscle activity and increased humeral head translation in patients with HSD and multidirectional shoulder instability 12 13. However, there is no gold standard management, and no studies have focused on treatments of the shoulder for this patient group 14–17.…”

“… 4 5 Recent studies have reported altered scapular kinematics, imbalanced electromyographic scapular muscle activity and increased humeral head translation in patients with HSD and multidirectional shoulder instability. 12 13 However, there is no gold standard management, and no studies have focused on treatments of the shoulder for this patient group. 14–17 Generally, an important and effective component of exercise interventions for persistent shoulder complaints—such as rotator cuff tendinopathy and anterior or multidirectional glenohumeral instability—aims to improve the function of the scapular stabilising muscles and rotator cuff muscles.…”