Imaging of traumatic shoulder injuries - Understanding the surgeon's perspective

Abstract

Imaging plays a key role in the assessment and management of traumatic shoulder injuries, and it is important to understand how the imaging details help guide orthopedic surgeons in determining the role for surgical treatment. Imaging is also crucial in preoperative planning, the longitudinal assessment after surgery and the identification of complications after treatment. This review discusses the mechanisms of injury, key imaging findings, therapeutic options and associated complications for the most common shoulder injuries, tailored to the orthopedic surgeon's perspective.

Keywords: ABER, abducted and external rotated; AC, acromioclavicular; AHI, acromiohumeral interval; ALPSA, anterior labral periosteal sleeve avulsion; AO, Arbeitsgemeinschaft für Osteosynthesefragen; AP, anteroposterior; Acromioclavicular (AC) joint separation; CT, computed tomography scan; Clavicle facture; GLAD, glenolabral articular disruption; Glenohumeral dislocation; MR, magnetic resonance; MRI, magnetic resonance imaging; ORIF, open reduction and internal fixation; Proximal humerus fracture; RCT, rotator cuff tear; Scapular fracture; Traumatic rotator cuff tear; US, ultrasound scan.

Fig. 1

Neer classification of proximal humerus fracture with (A) one-, (B) two-, (C) three-, (D) classic four-, and (E) valgus-impacted four-part fractures. In the classic four-part fracture, the humeral head articular surface no longer articulates with the glenoid, whereas the articulation is maintained in a valgus-impacted four-part fracture. GT, greater tuberosity; LT, lesser tuberosity; H, humeral head; S, humeral shaft; GL, glenoid.

Fig. 2

A 65-year-old woman with proximal humerus fracture. (A) Frontal shoulder radiograph shows a complex fracture through the surgical neck with displaced humeral head and greater tuberosity. (B and C) Nonenhanced coronal and axial CT images better characterize the injury as a four-part fracture, with the greater tuberosity (GT), lesser tuberosity (LT), humeral head (H), and humeral shaft (S) all displaced by ≥ 1 cm or angulated ≥ 45°.

Fig. 3

A 47-year-old male with proximal humerus fracture through the surgical neck in varus alignment. Varus alignment carries a worse prognosis compared to normal or valgus alignment.

Fig. 4

A 61-year-old man with proximal humerus fracture resulting in a large pseudoaneurysm. (A) Trans-scapular Y-view shows a displaced fracture through the surgical neck. Coronal CT angiography (B) and conventional angiography (C) reveals a pseudoaneurysm originating from anterior humeral circumflex artery origin (arrows) with surrounding hematoma. (D) Successful coil embolization of the pseudoaneurysm (arrowhead) is seen on angiography.

Fig. 5

A 51-year-old female with proximal humerus fracture complicated by hardware backout. (A) Right proximal humeral fracture with inferior dislocation of the humeral head in relation to the glenoid fossa is treated by surgical fixation (B). (C) One month postoperative radiograph shows complete separation of the humeral head from the superior fracture plate and screws (arrow) with recurrent humeral head subluxation, which required placement of a strut graft (D). H, humeral head; S, humeral shaft; GL, glenoid.

Fig. 6

A 60-year-old female with proximal humerus fracture complicated by avascular necrosis. (A) Left proximal humeral fracture with inferior posterior dislocation of the humeral head is treated by surgical fixation (B). (C) New collapse of the left humeral head with extension of screws beyond the articular surface (arrows) is consistent with avascular necrosis that is treated by reverse total shoulder arthroplasty (D).

Fig. 7

Glenohumeral dislocation types as categorized by location of the humeral head (H) in relation to the glenoid (GL). Anterior dislocation seen on anteroposterior (A) and trans-scapular Y (B) views. The latter shows migration of the humeral head towards the coracoid process (C). Posterior dislocation shows widening of the glenohumeral distance (black line) on the internal rotation view (C) and posterior migration of the humeral head in relationship to the coracoid process on nonenhanced axial CT image (D). Inferior dislocation (luxatio erecta) showing abduction of the affected arm on CT scout image (E) and inferior dislocation of the humeral head relative to the glenoid on nonenhanced coronal CT image (F).

Fig. 8

A 37-year-old man with anterior shoulder dislocation. (A) Anterior dislocation of the humeral head (H) in relation to the coracoid process seen on sagittal T2 weighted fat-suppressed MR image with a Hill-Sachs fracture (arrow) at the posterior superior humeral head. (B) Post-reduction axial T2 weighted fat-suppressed MR image reveals a bony Bankart fracture (arrow) at the anterior inferior glenoid.

Fig. 9

A 59-year-old man with posterior shoulder dislocation after closed reduction. (A) Frontal shoulder radiograph shows a reverse Hill-Sachs defect (arrow) at the anteromedial aspect of the humeral head. (B and C) Axial T2 weighted fat-suppressed MR images better show the reverse Hill-Sachs defect (arrow) and a chondrolabral tear along the posterior labrum (arrowheads).

Fig. 10

A 21-year-old man with persistent pain after arthroscopic Bankart repair with retained surgical hardware. Nonenhanced axial CT (A) and 3D reformatted sagittal (B) and coronal (C) images show a bony Bankart injury at the anterior inferior glenoid (arrows) with a retained metallic suture anteromedially (arrowheads).

Fig. 11

A 45-year-old man with anterior shoulder dislocation. Nonenhanced sagittal (A) and axial (B) CT images show respective anterior and medial displacement of the humeral head (H) in relation to the coracoid process (C) and glenoid (GL). (C) Post-reduction nonenhanced axial CT image shows the humeral head in normal alignment with the glenoid and a Hill-Sachs deformity (arrow).

Fig. 12

A 23-year-old man with prior anterior and posterior shoulder dislocation. Sagittal (A) and axial (B) post arthrogram CT images demonstrate anterior (arrows) and posterior (arrowheads) glenoid fractures.

Fig. 13

A 42-year-old man with unsuccessful relocation attempts of anterior shoulder dislocation. Small osseous fracture fragments (arrow) are seen preventing relocation of the humeral head over the glenoid on nonenhanced axial CT image.

Fig. 14

A 37-year-old woman with anterior glenoid fracture after anterior shoulder dislocation. (A) Axial post arthrogram CT image shows a bony bankart fracture (arrows) with normal attachment of the anterior labrum (arrowhead) to the fracture fragment. The size of the bankart fracture fragment is better shown on sagittal post arthrogram CT image (B) which helps in surgical planning. (C) 3D reformated image can estimate the degree of glenoid bone loss using a best-fit circle (red) that approximates the normal glenoid articular surface. The distance measured between the anterior margin of the circle and the anterior margin of the glenoid (white line) is divided by the circle diameter to calculate the percentage bone loss, which is 28% in this case.

Fig. 15

Arthrographic MRI appearances of Bankart variants at the anterior inferior labrum as indicated by labral defects (arrows) and osseous or periosteal defects (arrowheads). (A) normal, (B) labral Bankart, (C) osseous Bankart, (D) Perthes, (E) ALPSA, (F) GLAD. ALPSA, anterior labral periosteal sleeve; GLAD, glenolabral articular disruption.

Fig. 16

ABER MRI sequence. T1 weighted fat-suppressed MR arthrogram image with the arm in the ABducted and External Rotated position shows displacement of the anteroinferior labraligamentous complex (arrow). (Case courtesy of Dr. Andrew Haims, New Haven CT).

Fig. 17

55-year-old man with traumatic subscapularis tendon tear and biceps tendon dislocation sustained while skiing. Axial T2 weighted fat-suppressed MR images show complete tearing of the subscapularis tendon (arrow) with retraction. The long head of the biceps tendon (arrowhead) is dislocated medially due to subscapularis tendon disruption.

Fig. 18

A 60-year-old female with traumatic supraspinatus rotator cuff tear. Coronal (A) and sagittal (B) T2 weighted fat-suppressed MR images demonstrate a full-thickness (arrow), partial width (black line) tear of the supraspinatus tendon involving the anterior fibers with retraction of the frayed proximal tendon edge. There are intact posterior fibers (arrowheads) of the supraspinatus tendon. No tendon stump or osseous avulsion is seen.

Fig. 19

73-year-old man with rotator cuff atrophy. Sagittal T1 weighted MR image shows severe fatty atrophy of the supraspinatus (SP) and infraspinatus (IF) muscles. The “tangent sign” shows most of the supraspinatus muscle belly is below a tangential line (white line) between the coracoid and scapular spine.

Fig. 20

69-year-old female with history of prior open supraspinatus tendon repair found to have retear. (A) Coronal T1 weighted MR arthrogram image show complete tearing of the supraspinatus tendon (arrow) with retraction to almost the glenoid rim. (B) Sagittal T1 weighted fat-suppressed MR arthrogram image marks the expected locations of completely torn supraspinatus (arrow) and infraspinatus (arrowhead) tendons.

Fig. 21

A 56-year-old man with traumatic massive rotator cuff tear. (A) Frontal right shoulder radiograph shows narrrowing of the acromiohumeral interval (arrow) that is suggestive of supraspinatus tendon tear. Coronal (B) and axial (C) T2 weighted fat-suppressed MR images show complete rupture of the supraspinatus (arrow) and infraspinatus (arrowhead) tendons. (D) Intramuscular edema within the supraspinatus (SP) and infraspinatus (IF) can be consistent with acute trauma.

Fig. 22

44-year-old man with history of prior rotator cuff repair found to have postoperative denervation injury. (A) Coronal T1 weighted MR image shows suture anchors (arrowhead) attaching the repaired distal supraspinatus tendon (arrow) to the greater tuberosity. (B) Coronal T2 weighted fat-suppressed MR image shows diffuse intramuscular edema involving the deltoid (DT) and teres minor (TM), suggestive of denervation injury to the axillary nerve.

Fig. 23

A 24-year-old man with grade 2 acromioclavicular joint separation. (A) Frontal radiograph shows abnormal widening of the acromioclavicular interval (white line) between the acromion (A) and clavicle (C). (B) Coronal T1 weighted MR image shows disruption of the acromioclavicular joint capsule (arrow).

Fig. 24

36-year-old man with grade 3 left acromioclavicular joint separation. Anteroposterior radiograph shows abnormal widening of both acromioclavicular (black line) and coracoclavicular (white line) intervals.

Fig. 25

A 31-year-old man with grade 3 acromioclavicular joint separation. (A) Frontal radiograph shows abnormal widening of both the acromioclavicular (white line) and coracoclavicular (black line) intervals. (B) Coronal T2 weighted fat-suppressed MR image shows rupture of the coracoclavicular ligament (arrow) between the coracoid (CO) and clavicle (CL). (Case courtesy of Dr. Jennifer Nimhuircheartaigh, Limerick Ireland).

Fig. 26

28-year-old male with surgical hardware migration after AC joint reconstruction. (A) Frontal left shoulder radiograph shows widening of the AC (white line) and CC (black line) intervals consistent with grade 3 AC joint separation. Small osseous fragment (arrow) represents a fractured bone fragment. (B) Postoperative radiograph after AC joint reconstruction and placement of a surgical wire approximating the clavicle and coracoid (C) shows improved AC joint alignment. (C) The patient returns with persistent shoulder pain 2 month after surgery and repeat radiograph demonstrates superolateral displacement of the surgical wire, which no longer encircles the coracoid (C). The AC and CC intervals are again increased. AC, acromioclavicular; CC, coracoclavicular.

Fig. 27

50-year-old male with AC hook plate migration after AC joint injury. (A) Frontal right shoulder radiograph shows widening of the AC (white line) and CC (black line) intervals that is consistent with grade 3 AC joint separation. (B) Postoperative radiograph shows improved AC joint alignment after AC hook plate placement. (C) The patient returns with persistent postoperative pain and nonenhanced CT study demonstrates superior migration of the distal hardware in relation to the acromion (A). AC, acromioclavicular; CC, coracoclavicular.

Fig. 28

Allman Classification of clavicular fractures based on their location: group 1, middle third; group 2, lateral third; group 3, medial third.

Fig. 29

Various types of clavicular fractures. (A) Comminuted group 1 midshaft fracture (arrowhead) with associated moderate sized pneumothorax (arrows). Comminuted group 2 lateral clavicular fracture (arrowhead) in the region of the coracoclavicular ligaments seen on frontal radiograph (B), with coronal nonenhanced CT image (C) showing an intact lateral trapezoid ligament (arrow); however, the medial conoid ligament is disrupted (arrowhead). (D) Comminuted lateral clavicular fracture with a displaced vertical “zed” fragment (arrow), which carries a higher rate of non-union, and acromioclavicular joint separation.

Fig. 30

A 32-year-old man with clavicular fracture plate failure. (A) Frontal right shoulder radiograph shows a midshaft clavicular fracture (arrow) with apex superior angulation that is corrected by a surgical fixation plate (B). (C) The patient returns with postoperative shoulder pain and deformity, and repeat radiograph demonstrates displacement of the fixation plate allowing recurrent angulated deformity of fracture fragments.

Fig. 31

A 37-year-old man with glenoid fracture. Nonenhanced coronal CT (A) and 3D reformatted sagittal (B) images show a fracture of the middle portion of the glenoid with articular stepoff (arrows).

Fig. 32

A 45-year-old man with scapular fracture. (A) Trans-scapular Y view shows a displaced scapular body fracture (arrow). (B) Nonenhanced axial CT image shows associated extensive pneumomediastinum (arrows) and left clavicular fractures (arrowhead).