Irreducible posterior fracture and dislocation of shoulder with massive rotator cuff tear due to incarceration of biceps tendon: A case report

Abstract

Acute traumatic posterior glenohumeral dislocation in association with a massive rotator cuff tear is rare. Moreover, only few cases with interposition of the long biceps head of the tendon has been described to prevent reduction in posterior dislocation of the shoulder. In addition, combined scapula fracture with posterior shoulder dislocation also extremely rare. We present a case of Irreducible posterior fracture and dislocation of shoulder with massive rotator cuff tear due to incarceration of biceps tendon. For the treatment arthroscopic in situ superior capsule reconstruction was performed using the long head of the biceps tendon with rotator cuff repair.

1. Introduction

Posterior shoulder dislocation occurs infrequently, occupying 2%–5% of all shoulder dislocation. It occurs when extreme muscle contraction such as seizures, electrical shocks or trauma injury with shoulder flexion, adduction, and internal rotation.¹ Typical clinical features of the posterior shoulder dislocation are including as follow: posterior protrusion of the humeral head with anterior shoulder flattening contour, limited range of motion in shoulder external rotation, internal rotation, forward elevation.¹ Massive rotator cuff tears (RCTs) are more commonly known to occur with traumatic anterior glenohumeral dislocations in patients older than 40 years of age, usually an elderly female who falls on her outstretched hand or the very occasional young patient.2, 3, 4, 5 Massive RCTs rarely occur with posterior glenohumeral dislocations, regardless of patient age. To our knowledge, only few documented cases have been reported involving posterior dislocations with massive RCTs.^3,6, 7, 8

Irreducibility of a glenohumeral dislocation can occur because of a large osteochondral humeral defect or because of soft tissue interposition in the glenohumeral joint.⁹ In posterior dislocation of the shoulder, interposition of the long biceps head of the tendon has been described to prevent reduction.10, 11, 12 In posterior dislocation of glenohumeral joint, the most common fracture was neck fracture (18.5%) followed by lesser tuberosity (14.3%) and greater tuberosity (7.8%).¹³ Other fractures (humerus diaphysis, scapula, clavicle, or any other fracture) were present in 6.0%.¹³ To our knowledge, this case is the first occurrence, so authors supposed to report a case for irreducible posterior fracture and dislocation of shoulder with massive rotator cuff tear due to incarceration of biceps tendon.

2. Case report

A 57-year-old man visited the emergency room with left shoulder pain developing after motorcycle driver injury. Physical examination revealed general tenderness in the left shoulder, and other tests including range of motion (ROM) was not performed because of shoulder pain. Plain radiograph and computed tomography (CT) of the left shoulder showed posterior dislocation of glenohumeral joint and scapula body fracture (Fig. 1) At this time, he underwent an attempted closed reduction of his left shoulder under conscious sedation. However, reduction was impossible probably because of soft tissue interposition. Post-reduction magnetic resonance imaging (MRI) showed posteriorly subluxation of shoulder with massive RCT due to incarceration of biceps tendon (Fig. 2). At 3 days after trauma, we decided to perform surgical treatment for reduction of glenohumeral joint and repair of massive RCT.

Fig. 1.

(A) Pre-operative plain radiograph of shoulder Anterior-posterior view, (B, C) Pre-operative 3 dimensional Computed Tomography of shoulder showing posterior glenohumeral dislocation of the injured shoulder.

Fig. 2.

Pre-operative magnetic resonance images (A, B) Coronal and saggital T2 weighted images showing massive rotator cuff tear, (C, D) Axial and coronal T2 weighted images showing interposition of the long head of the biceps tendon. Arrowhead; long head of the biceps tendon.

The patient is positioned in the lateral decubitus position with the affected arm in 10 lbs. of balanced longitudinal and lateral suspension via use of the STAR device (Arthrex, Naples, FL). A standard posterior portal is created for initial intra-articular visualization. Under direct visualization, the anterior working portal (anteroinferior portal) is created through the rotator interval using the outside-in technique. The biceps tendon was dislocated from the bicipital groove and located between glenoid and humeral head, preventing reduction of the glenohumeral joint (Fig. 3A). Massive full thickness RCT involving the subscapularis, supraspinatus, and infraspinatus was revealed and the glenohumeral joint superior capsule was also disrupted (Fig. 3B and C).

Fig. 3.

Intraoperative arthroscopic findings. (A) Interposition of the long head of the biceps tendon at the glenohumeral joint was observed. (B, C) Massive full thickness RCT involving the subscapularis, supraspinatus, and infraspinatus was observed. H: Humerus, LHBT: Long head of the biceps tendon, RC: Rotator cuff.

For the accurate reduction of the glenohumeral joint and reconstruction of superior capsule, arthroscopic in situ superior capsular reconstruction (SCR) using the long head of the biceps tendon (LHBT) was performed (Fig. 4A).¹⁴ After two medial anchors insertion (Triple loaded Y-Knot® RC All-Suture Anchor; ConMed, New York, New York), LHBT was moved between two medial anchors and one wrap-around tie with posterior medical anchor was also made. After finishing the arthroscopic in situ SCR with the LHBT, rotator cuff repair was performed using suture bridge technique with additional lateral row suture anchors (3.5-mm PushLock; Arthrex, Naples, FL) (Fig. 4B).

Fig. 4.

Intraoperative arthroscopic findings. (A) After superior capsule reconstruction with rerouting of long head of the biceps tendon. (B) After finishing the rotator cuff repair. H: Humerus, LHBT: Long head of the biceps tendon, RC: Rotator cuff.

3. Post-operative rehabilitation and clinical outcomes

The patient wore a shoulder immobilizer (Ultrasling ER; Donjoy, Vista, CA) that kept the shoulder at 30° of external rotation for 6 weeks postoperatively. Only pendulum exercises and scapular retraction were accepted during the period with a shoulder immobilizer. For the next 6 weeks after the immobilization period, progressively increase the ROM and pain free strength exercise were allowed. In 12–16 weeks, a more intensive strengthening exercise regimen was allowed and the patient was able to return to work.

The patient showed remarkable progress through postoperative recovery and rehabilitation. He recovered well for 6 months after discharge and returned to daily life and work, ROM of the shoulder joint was full and Follow-up sonography at 6 months showed healed tendon without retear (Fig. 5). Also, the VAS score at this time was 2 out of 10, and the American Shoulder and Elbow Surgeon score was 85 of 100, and the Korean shoulder scoring system was 88 of 100 that represent the excellent prognosis respectively.

Fig. 5.

Postoperative follow up sonography at the six months showed healed tendon without re-tear.

4. Discussion

Rotator cuff tears are well recognized to occur in association with traumatic anterior shoulder dislocation; especially in patients over 40 years of age.2, 3, 4, 5 However, an association with a posterior dislocation is rare regardless of the patient age.^3,6, 7, 8^,15 To our knowledge, this is the first case to report a irreducible posterior dislocation of shoulder with massive rotator cuff tear due to interposition of the long biceps head of the tendon which prevent reduction and combined scapula fracture.

Based on the clinical evidence available in present and prior reports, all massive rotator cuff tears in posterior shoulder dislocations were identically avulsed from the humeral origin, the supraspinatus and infraspinatus were consistently involved.^3,6, 7, 8^,15 The tears may have extended anteriorly into the subscapularis and posteriorly into the teres minor.^3,6, 7, 8^,15 Complete tearing of the entire rotator cuff tendon could occur when the injury was extremely severe as seen in one of our cases and in one of the previous reports.⁶ According to the current literature, there are only few cases which had interposition of the long head of the biceps tendon has been described to prevent reduction after posterior shoulder dislocation.10, 11, 12 In addition, combined scapula fracture with posterior shoulder dislocation is also extremely rare.¹³ This case is the first case to report a irreducible posterior dislocation of shoulder due to incarceration of biceps tendon with massive rotator cuff tear and scapula fracture.

The superior capsule is an important glenohumeral joint static stabilizer.^16,17 This function explains why the superior capsule reconstruction (SCR) can improve disability and relieve pain in massive rotator cuff tears.^18,19 In a cadaver study, Ishihara et al.¹⁷ reported that a defect in the superior capsule can increase glenohumeral translations, which means that alterations in the shoulder joint stability due to a defect in the superior capsule can cause progression of cuff tear arthropathy. Mihata et al.^18,19 demonstrated good clinical outcomes from this reconstructive procedure. Arthroscopic repair of massive RCTs is associated with a high retear rate, especially in traumatic RCTs.^20,21,²² Mihata et al.²² also reported that SCR for reinforcement prevented retear at 1 year after rotator cuff repair and improved the quality of the repaired tendon on MRI. Recently, Kim et al.¹⁴ demonstrated an arthroscopic SCR technique using LHBT rerouting without autologous tensor fascia lata graft. This technique is good for preventing donor-site morbidity and reducing infection risk and operation time in the harvesting and preparation of graft tendon. In this case, the authors determined SCR with biceps rerouting technique for the reduction of incarceration of biceps tendon at the glenohumeral joint and reinforce of massive rotator cuff repair. As a result, satisfactory outcomes were obtained without retear or other complications.