Evaluation of Inferior Capsular Laxity in Patients with Atraumatic Multidirectional Shoulder Instability with Magnetic Resonance Arthrography

Abstract

Objective To compare inferior capsular redundancy by using magnetic resonance arthrography (MRA) images in patients with multidirectional instability (MDI) of the shoulder and control subjects without instability and thereby develop a screening method to identify the presence of shoulder MDI. Materials and Methods The MRA images of patients with MDI of the shoulder (n = 65, 57 men, 8 women; mean age, 24.5 years; age range, 18–42 years) treated over an eight-year period were retrospectively reviewed; a control group (n = 65, 57 men, 8 women; mean age, 27.4 years; age range, 18–45 years) without instability was also selected. The inferior capsular redundancy was measured using a new method we named the glenocapsular (GC) ratio method. MRA images of both groups were randomly mixed together, and two orthopedic surgeon reviewers measured the cross-sectional areas (CSAs) and sagittal capsule-head ratios on oblique sagittal images, as well as the axial capsule-head ratios on axial images and GC ratios on oblique coronal images. Results The CSAs and GC ratios were significantly higher in patients than in controls (both, p < 0.001); however, the sagittal capsule-head ratios and axial capsule-head ratios were not significantly different ( p = 0.317, p = 0.053, respectively). In addition, GC ratios determined the presence of MDI more sensitively and specifically than did CSAs. A GC ratio of > 1.42 was found to be most suggestive of MDI of the shoulder, owing to its high sensitivity (92.3%) and specificity (89.2%). Conclusion GC ratio can be easily measured and used to accurately screen for MDI of the shoulder.

Management of shoulder instability in hypermobility-type Ehlers-Danlos syndrome

“…Magnetic resonance arthrography (MRA) either with saline or with contrast 77 has an advantage in this regard, as it is a more sensitive modality in detection of capsular laxity and redundancy (Figure 4). The particular finding on MRA for this pathology is J o u r n a l P r e -p r o o f an increase in the glenocapsular ratio, which is supportive of a diagnosis of hEDS 61 . In contrast to healthy patients with traumatic dislocations, the absence of a labral tear on cross-sectional imaging of an unstable shoulder is often more suggestive of a diagnosis of underlying hEDS.…”

Magnetic resonance arthrography in patients with multidirectional instability: could inferior capsulsar width be considered the cornerstone in the diagnosis of non-traumatic shoulder instability?

“…As inferior instability is the main component of MDI of the shoulder, previous authors experimented different methods to measure capsular redundancy, such as gleno-capsular ratio or labro-capsular distance and they all agree that increased axillary recess depth is correlated to shoulder instability [8,10]. Lee et al and Kim et al also found significant correlation between inferior capsular redundance and MDI [19,20].…”

“…Different methods have been previously reported; some authors have shown how an increased capsular volume, expressed as the three-dimensional capsular volume with respect to glenoid surface, and an increased sagittal cross-sectional capsular area are related to MDI [8,14]. However, they also observed that the glenoid surface area is not significantly different in patients with or without atraumatic instability.…”

“…Imaging may be useful in the diagnosis of MDI; in particular magnetic resonance arthrography (MR-a) may demonstrate an increased capsular volume defined by the glenocapsular ratio [1,7], although these measures are difficult to reproduce [8].…”

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

“…Three studies defined a symptomatic patient as a patient with pain alone ( 58 , 59 , 60 ), while eight studies accepted instability and/or subluxation and/or dislocation alone ( 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ). Twelve studies did not explicitly state what patient history would constitute a symptomatic patient ( 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 ).…”