MR imaging in sports-related glenohumeral instability

Abstract

Sports-related shoulder pain and injuries represent a common problem. In this context, glenohumeral instability is currently believed to play a central role either as a recognized or as an unrecognized condition. Shoulder instabilities can roughly be divided into traumatic, atraumatic, and microtraumatic glenohumeral instabilities. In athletes, atraumatic and microtraumatic instabilities can lead to secondary impingement syndromes and chronic damage to intraarticular structures. Magnetic resonance (MR) arthrography is superior to conventional MR imaging in the diagnosis of labro-ligamentous injuries, intrinsic impingement, and SLAP (superior labral anteroposterior) lesions, and thus represents the most informative imaging modality in the overall assessment of glenohumeral instability. This article reviews the imaging criteria for the detection and classification of instability-related injuries in athletes with special emphasis on the influence of MR findings on therapeutic decisions.

Fig. 1a, b

ABER position: normal findings. a Coronal localizer image of the shoulder obtained in abduction and external rotation shows correct orientation of transverse oblique sections aligned with the humeral shaft. b Resulting transverse oblique T1-weighted MR arthrogram demonstrates normal appearance of anteroinferior labrum (white arrow) with taut IGHL (arrowheads), posterosuperior labrum (black arrow), and supraspinatus tendon (**) (T greater tuberosity of humeral head)

Fig. 2a–f

Classification of Bankart and Bankart variant lesions. a Bankart lesion, b bony Bankart lesion, c Perthes lesion, d ALPSA (anterior labro-ligamentous periosteal sleeve avulsion) lesion, e GLAD (glenolabral articular disruption) lesion, f HAGL (humeral avulsion of glenohumeral ligaments) lesion. (LLC anteroinferior labro-ligamentous complex, P scapular periosteum, HH humeral head, AC articular cartilage of glenoid, IGHL inferior glenohumeral ligament)

Fig. 3a–c

Bankart lesion. a Transverse and b coronal oblique T1-weighted MR arthrograms show complete detachment of the anteroinferior labrum (arrows) which “floats” within the anterior capsular recess but remains attached to the IGHL (arrowheads). c Fat-suppressed T1-weighted MR arthrogram obtained in ABER position reveals separation of the anteroinferior labrum from the glenoid edge as well as disruption of the periosteum (arrow). Note taut IGHL adherent to the labrum (arrowhead)

Fig. 4a–d

Bony Bankart lesion. a Coronal oblique and b transverse T1-weighted MR arthrograms show avulsion of a large osseous fragment (arrowheads) from the glenoid together with the attaching anteroinferior labrum and IGHL (arrow). c Sagittal oblique T1-weighted MR arthrogram demonstrates “inverted peer” geometry of glenoid in presence of a “relevant” bony Bankart lesion (arrowhead). Note smaller anteroposterior diameter of glenoid below (**) midglenoid notch than above (++) it. For comparison, normal peer-shaped configuration of glenoid is shown on d sagittal oblique T1-weighted MR arthrogram from individual with stable shoulder (C coracoid process)

Fig. 5a, b

Perthes lesion. a Transverse fat-suppressed T1-weighted MR arthrogram shows detachment and slight displacement of the anteroinferior labro-ligamentous complex (arrow) and stripping of the intact scapular periosteum (arrowhead). On b corresponding T1-weighted MR arthrogram obtained in ABER position the anteroinferior labrum is realigned with the glenoid edge by the taut IGHL (arrowhead). Although the tear is still demarcated by contrast media (arrow), it is less conspicuous than on the conventional transverse section in this case. (M middle glenohumeral ligament

Fig. 6a, b

ALPSA lesion. a Coronal oblique and b transverse T1-weighted MR arthrograms demonstrate a nodular shaped anteroinferior labroligamentous complex (arrows) that is displaced medially and inferiorly on the scapular neck. Note cleft (arrowheads) between fibrous tissue and glenoid

Fig. 7

GLAD lesion. Transverse T1-weighted MR arthrogram shows a nondisplaced tear of the anterior labrum (arrow) associated with a full-thickness chondral defect of the anterior glenoid (arrowhead). A small fragment of hyaline cartilage adheres to the torn labrum

Fig. 8a, b

HAGL lesion. a Coronal oblique fat-suppressed T1-weighted MR arthrogram and b corresponding intermediate weighted TSE image demonstrate avulsion of the IGHL at its humeral insertion causing a J-shaped configuration of the axillary recess (arrowheads). Contrast extravasation can be seen at the site of the tear (arrows). Bone marrow edema within humeral head (*) was caused by acute Hill-Sachs defect (not shown)

Fig. 9

Nonclassifiable anteroinferior labro-ligamentous injury. Transverse T1-weighted MR arthrogram shows markedly deformed and enlarged labro-ligamentous complex without differentiability of labrum, IGHL, and scapular periosteum. The lesion was associated with chronic anteroinferior instability

Fig. 10a–c

Hill-Sachs defect: MR appearance. a Acute lesion: transverse fat-suppressed intermediate weighted TSE image shows impaction of the posterolateral humeral head (arrowhead) with adjacent bone marrow edema following acute anteroinferior dislocation. b, c Chronic lesions: b transverse fat-suppressed T1-weighted and c transverse T1-weighted MR arthrograms obtained in two different patients several months after anteroinferior dislocation depict circumscribed (b) and extensive (c) osteochondral defects (arrowheads) of the humeral head (C tip of coracoid process)

Fig. 11a, b

Atraumatic glenohumeral instability: labral degeneration. a Transverse fat-suppressed T1-weighted and b corresponding sagittal oblique T1-weighted MR arthrograms reveal markedly swollen and enhanced but nondisplaced anterior glenoid labrum in an athlete with multidirectional shoulder instability. Extensive labral degeneration was verified by arthroscopy (not shown)

Fig. 12a–e

PSI: spectrum of findings on MR arthrography. a Transverse fat-suppressed T1-weighted MR arthrogram and b, c corresponding coronal oblique images obtained in a tennis player with posterior shoulder pain show a posterosuperior labral tear (arrow in a) associated with an articular-sided partial tear of the posterior aspect of the supraspinatus tendon (arrowhead in b) and a SLAP type 2 lesion (arrow in c). Note large volume of anterior capsule (* in a). d, e T1-weighted MR arthrograms obtained in ABER position from two athletes with PSI: d Arthrogram demonstrates the “kissing lesion” pattern with corresponding tears of the posterosuperior labrum (white arrow) and the undersurface of the supraspinatus tendon (black arrowhead) accompanied by sclerosis of the greater tuberosity of the humeral head at the contact zone with the glenoid (black arrow). Note elongation of the IGHL (white arrowhead). e Arthrogram shows interposition of the supraspinatus tendon (*) between the greater tuberosity and the superior glenoid as well as a tear of the IGHL (arrowhead) with consecutive contrast extravasation

Fig. 13a–d

SLAP lesions: classification according to Snyder [56] on coronal oblique MR arthrograms (from [35]; modified). a SLAP type 1 lesion, b SLAP type 2 lesion, c SLAP type 3 lesion, d SLAP type 4 lesion (LBC labral-bicipital complex, HH humeral head, G glenoid)

Fig. 14

Sublabral recess. Coronal oblique T1-weighted MR arthrogram demonstrates medially oriented cleft (arrowhead) between the superior labrum and the glenoid outlined by contrast media which was also diagnosed as a sublabral recess with a stable biceps insertion on arthroscopy (not shown). Note meniscoid shape of superior labrum (*) and integrity of the biceps anchor (arrow)

Fig. 15a–d

SLAP type 2 lesion in association with a Bankart lesion in traumatic anterior glenohumeral instability. a Coronal oblique fat-suppressed T1-weighted MR arthrogram shows superior extension of contrast media into the superior labrum and biceps anchor (arrowhead). b Corresponding sagittal oblique MR arthrogram reveals tearing of the entire anterior labrum (arrowheads) extending from inferior to superior. c, d Corresponding transverse MR arthrograms demonstrate detachment of the anterior labrum that continues as a classic Bankart lesion anteroinferiorly (arrows)