1 Introduction

Postoperative deltoid muscle ruptures have been described in literature as a complication of open rotator cuff repair.¹ The anterior and middle portion of the deltoid muscle are the most common locations for muscular tearing due to the dettachment needed to improve surgical access to the rotator cuff in open repair techniques.² Deltoid rupture leads to muscle insufficiency, tendon retraction and subdeltoid adhesions resulting in important functional impairment and pain.^3,4 The incidence of this condition is still unknown.⁴

Although some authors advocate that small acute deltoid ruptures (inferior to 3 cm) after rotator cuff repair may be treated non-surgically, surgical re-insertion might be indicated in ruptures greater than 3 cm.⁴

The authors present a clinical case of deltoid rupture after failed open rotator cuff tear repair, discussing the clinical and radiological characteristics of this entity that are essential to diagnosis as well as our surgical approach through the review of the current literature.

2 Case report

The authors report a case of a 55-year-old woman, right-hand-dominant, previously submitted to right shoulder surgery - open supraspinatus tendon repair and lateral acromioplasty. Due to persistent shoulder disfunction and pain, she was referred to our institution one year after surgery. The patient reported an initial pain score in visual analog scale (VAS) of 7/10, and a Disabilities of Arm, Shoulder and Hand score (DASH score) of 72,5.

3 Clinical findings

Clinical examination revealed asymmetrical contour of the shoulders, with the right shoulder presenting lateral soft tissue subacromial depression and tenderness in the anterior and lateral portion of the acromion (Fig. 1). There was clear limitation of active range of movement, being capable of 100° of anterior elevation. There was also significant deficit of abduction strength and scapular dyskinesia. Jobe test and drop arm test were positive, indicating insufficiency of the supraspinatus tendon. Under resisted abduction the gap in the anterolateral deltoid became more pronounced. The strength and mobility of the contralateral shoulder were normal. The remaining physical examination was unremarkable.

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Fig. 1a (anterior view), 1b (antero-lateral view) and 1c (superior view): Images eliciting lateral soft tissue subacromial depression around the middle head of the right deltoid and previous scar.

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4 Diagnostic assessment

The plain radiographs showed mild acromioclavicular degenerative changes but with subacromial space within normal range. The magnetic resonance imaging (MRI) revealed a complete re-rupture of the supraspinatus tendon with 24 mm dimension in the coronal plane with mild fat infiltration (grade I of the Goutallier classification) and no relevant myotendinous retraction (Fig. 2b). The long head of the biceps brachii tendon (LHBB) was restricted to the bicipital groove displaying minor synovial distension. The evaluation of the deltoid muscle elicited discontinuity of the middle head with the gap occupied by fibrous tissue (Fig. 2a).

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Fig. 2a T2-weighted MRI eliciting discontinuity of the middle head of deltoid muscle. Yellow arrow pointing to the retracted deltoid muscle margin.

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Fig. 2b Fat-suppressed T2-weighted MRI eliciting complete re-rupture of the supraspinatus tendon in the coronal plane.

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5 Differential diagnosis

Cervical spine pathology was excluded. Merging clinic and radiological findings the diagnosis of right rotator cuff re-tear and deltoid rupture was made.

6 Therapeutic intervention

After discussion of all treatment options, the patient opted to undergo surgical treatment.

The patient was positioned in a beach chair position after interscalene block and induction of general anesthesia. An open procedure through a sabercut incision was preferred to address the deltoid rupture a concomitant supraspinatus re-tear.

Dissection progressed to the level of deltoid fascia. Intraoperative inspection of the deltoid revealed that middle deltoid head was detached from its origin and retracted distally (Fig. 3a). After wide recession of the fibrous tissue over the insertion of middle head of deltoid, the greater tuberosity of the humerus was exposed and decorticated. Repair of supraspinatus tear was then performed using a double-row suture technique: a 2.6mm triple loaded all-suture anchor (Fibertak® - Arthrex) was inserted just lateral to the articular margin, the tapes were passed through the supraspinatus tendon, and laterally fixed in the greater tuberosity using a 4.75 mm anchor (Swivelock® - Arthrex).

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Fig. 3a Sabercut approach to the plane of the deltoid muscle, revealing middle deltoid head detachment and its substitution by fibrous tissue (delimitated by white dotted area).

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To reinsert the deltoid muscle, the remaining acromion was gently decorticated, and five transosseous tunnels were made using a 1,0 mm drill bit (Fig. 3b). The Fiberwires® were passed through the transosseous tunnels and 1 cm from the upper margin of the disinserted deltoid. Sequential tightening of the sutures with simple stitches was performed with the shoulder in 90^o of abduction to reduce stress in the repair site, providing satisfactory approximation without overtensioning of the middle head of the deltoid to its anatomical insertion in the acromion. Intraoperative testing of the repair with mobilization of the shoulder elicited good patency of the suture at the repair site (Fig. 3c).

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Fig. 3b Fibrous tissue wide resection, acromion exposure and decortication (bone tunnels positioning illustrated in green dots).

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Fig. 3c Final aspect of the deltoid reattachment. Note the restauration of the deltoid contour.

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After profuse irrigation and hemostasis revision the deltotrapezoid fascia was closed with a running absorbable suture and the wound was closed in a layered fashion.

7 Follow-up and outcomes

The patient was immobilized with a 30° abduction brace for four weeks and through this period was allowed to perform restricted pendular shoulder exercises and active mobilization of the elbow. At four weeks after surgery the patient initiated a physical rehabilitation program starting with passive and assisted active mobilization of the shoulder in sagittal, coronal and scapular plane and at eight weeks the patient initiated active mobilization with strengthening of the scapula stabilizers and hydrotherapy. At three months postoperatively, the patient presented a significant increase in active range of movement with 150^o of anterior elevation, 120^o of abduction and 60^o of external rotation. At one year follow-up the patient referred no shoulder pain at rest and minimal pain when sleeping on the affected side and at the extremes of shoulder range of movement, with a reported VAS score of 3/10. There was also a significant functional improvement with a final assessed DASH score of 35. The control MRI showed patency of supraspinatus tendon tear re-insertion and healing of the middle deltoid rupture as show in coronal T2-weighted images (Fig. 4a and b).

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Fig. 4a Postoperative T2-weighted MRI showing deltoid healing to the insertion site in the acromion.

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Fig. 4b Postoperative T2-weighted MRI showing supraspinatus tendon healing after double-row repair.

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8 Discussion

Rotator cuff repair is one of the most frequent procedures in shoulder surgery. Until the spread of arthroscopic techniques, open repair was the gold standard procedure in surgical treatment of this pathology.¹ In classical open repair techniques, deltoid detachment was performed routinely to allow better visualization and access to the rotator cuff tendon tear. This approach is associated with a higher incidence of deltoid origin injury.² Gumina et al., reported an incidence of 8% of postoperative deltoid rupture following massive rotator cuff tear open repair. In all the cases, acromioplasty was performed. Therefore, the authors hypothesized that extensive lateral acromioplasty could be an additional risk factor to postoperative deltoid rupture as over-resection of the acromion may cause weakness at the origin of the deltoid.⁴ More recently, Kholinne et al., described a slightly inferior incidence of deltoid detachment in their series (5.4%), reiterating that meticulous re-attachment of the deltoid has been proven to be a crucial step when performing open rotator cuff repair surgery.² Failing to do so, may result in progressive shoulder pain, functional impairment, and aesthetical deformity.

Cho et al., proposed a topographical classification of the proximal deltoid into 5 zones and showed that deltoid ruptures after open rotator cuff repair mostly occur in zone 2 (anterior acromion) and zone 3 (anterior third of the lateral acromial border).¹ Like the series of Morisawa et al., in our case the rupture affected the middle deltoid head (zone 3).⁵

Clinically, deltoid rupture in the setting of an open rotator cuff repair may be suspected if the patient complaints of sudden onset of shoulder pain, associated with weakness and limited shoulder range of movement.⁶ Soft tissue subacromial depression around the deltoid is an uncommon clinical finding, occurring in 8,3% of the cases, as stated by Ilaslan et al.⁷

According to Matzen et al., small acute deltoid ruptures (inferior to 3cm) after rotator cuff repair might be managed with non-operative treatment. In the other hand, surgical re-insertion might be indicated in ruptures greater than 3cm.⁸

In our clinical case, the patient presented progressive shoulder pain, important functional deterioration and evident subacromial soft tissue depression around the deltoid. The MRI documented a supraspinatus tendon full thickness re-tear and a significant middle deltoid head detachment. Our surgical approach consisted in a double-row reinsertion of supraspinatus tendon and a deltoid transosseous suture to the acromion as previously described by Gerber et al.⁸ Differently to Alben et al.,⁶ that preconized the use of a 3-hole mini plate over the acromion in order to minimize stress at the repair site and avoid bone cut-out, we decided to avoid the use of an extra implant that could possibly lead to a revision surgery in the future to remove the plate. Furthermore, the intraoperative testing of the repair with mobilization of the shoulder elicited good patency of the suture at the repair site. Nevertheless, we recognize that the use of this neutralization plate could be a good option in patients with bad bone stock or osteoporosis.

One year after surgery the patient obtained a significant improvement in pain and functional scores, regaining a good range of motion with sporadic complaints when sleeping on the affected side and extreme movements.

In this case the presence of concomitant supraspinatus re-tear and deltoid detachment makes it difficult to attribute the functional incapacity to one lesion or another, however, given the evident deltoid lesion we decided to address both lesions simultaneously.

In our opinion, this case reiterates that meticulous re-attachment of the deltoid is a crucial step when performing open rotator cuff repair surgery.

Financial support and sponsorship

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Informed consent

Informed consent was obtained from the patient for the publication of the case study.

Institutional ethical committee aproval

Ethical approval for this study was obtained by Ethical Committee of our Instituition.

CRediT authorship contribution statement

Diogo Soares: Conceptualization, Methodology, Writing – original draft. Francisco Bernardes: Visualization, Investigation. João Lixa: Visualization, Investigation. João Afonso: Supervision, Project administration, Writing – review & editing.