Transmural supraspinatus tendon tear caused by suture anchor tip 19-month postacromioclavicular joint stabilisation

Abstract

Rotator cuff injuries present rarely in paediatric patients due to the tendon strength at this age. There are reports of ruptures caused by either irritation of the lateral clavicle or acromioclavicular (AC) joint in fractures or after usage of hook plates. In this case report, we present a patient with an acute complete supraspinatus rupture caused by a suture anchor tip from a previously performed AC joint stabilisation. After the diagnosis of a new complete supraspinatus, the causative prominent suture anchor was removed, and the tendon subsequently repaired. This case highlights the close anatomic relation of the AC joint and the rotator cuff, which is imperative to adequately address in injuries to this anatomical location.

Background

The prevalence of rotator cuff tears increases with age secondary to degenerative changes in the tendon. Complete ruptures of the rotator cuff tendons in the paediatric population are rare and mostly related to traumatic shoulder injuries.^{1 2} Rotator cuff injuries in patients younger than 20 years are extremely uncommon due to normal tissue integrity with failure loads of up to 2000N.^{3 4} Yet, internal impingement, especially in overhead athletes (ie, volleyball or tennis player), is a frequent cause for partial rotator cuff tears in the younger population. Other rare causes of rotator cuff injuries include direct irritation by fracture of the lateral clavicle or acromioclavicular (AC) joint stabilisation with devices like the hook plate.^{5 6} Despite the close anatomical relationship, impairment of the rotator cuff integrity is not often reported in other types of AC joint stabilisation surgery. We present the case of a young man with a transmural supraspinatus tendon tear caused by the tip of a suture anchor used in a previously performed AC joint repair, which perforated the inferior cortex of the lateral clavicle.

Case presentation

A 17-year-old man with a history of grade V AC joint injury according to Rockwood of his right shoulder following a snowboarding accident who was managed with open AC stabilisation at an external institute now presented to our hospital with a painful AC Joint.⁷ He was treated with open coracoacromial refixation using nonabsorbable sutures with fixation button on the coracoid and the clavicle and suture anchor repair (2×2.8 mm anchors) of the AC ligament (figure 1). Rehabilitation was slow with the patient complaining of pain over the AC joint. Both an arthro-MRI 2 months and a CT scan 10 months postoperatively showed no signs of rotator cuff injury or glenohumeral injury but an osteophyte on the anterolateral aspect of the clavicle (figure 2). This matched the clinical finding of explicit pain on palpation of the anterolateral aspect of the clavicle, thus open surgery was indicated 11 months after AC joint stabilisation. During the surgery, the osteophyte on the anterolateral end of the clavicle was resected and a loose suture anchor on the acromion was removed. The other suture anchor in the posterior part of the lateral clavicle was not visible intraoperatively and therefore left in place because there was no sign of cuff irritation or loosening in that area. Postoperatively, the patient was symptom-free and presented with full function of his right shoulder. During a soccer match approximately 8 months after surgery, the patient fell on his right shoulder as a goalkeeper. He reported immediate pain and the inability to lift his right arm. After persistence of symptoms for more than 1 week the patient was referred to us for re-evaluation. Clinical examination showed a symmetrical, strong shoulder relief with unsuspicious scars and a minimal piano key phenomenon over the right AC joint. The active function of the shoulder showed a flexion up to 160° (contralateral side 180°) with marked pain from the horizontal (painful arc from 90 to 160°) with painful but strong internal rotation to L5. Both Jobe and Whipple test were painful. The passive glenohumeral range of motion was symmetrical with an abduction of 90° and an external rotation 60° without a lag.

Figure 1.

Post-traumatic radiograph showing a high-grade AC joint separation (A). Postoperative after open reduction and stabilisation (B). AC, acromioclavicular.

Figure 2.

No signs of rotator cuff tear on the MRI scan 10 months after initial trauma (A) but an osteophyte was detectable on the CT scan which was congruent with the clinical findings of a painful resistance anterior to the lateral clavicle (B).

Investigations

Further investigation with X-ray and arthro-MRI using a metallic artefact reduction sequence was initiated. X-ray showed no evidence of a fracture or dislocation with an unchanged position of the suture anchors for the AC stabilisation. Arthro-MRI revealed a complete supraspinatus tendon rupture at the greater tuberosity with a retracted tendon to the level of the glenoid (figure 3).

Figure 3.

MRI scan showing new complete supraspinatus tendon tear in coronal (A) and sagittal plane (B) with retraction of the tendon to the level of the glenoid.

Treatment

Based on the diagnosis of the complete, traumatic supraspinatus tendon tear yet good muscle quality, the indication for surgical tendon reconstruction was given. First, we performed a diagnostic shoulder arthroscopy which confirmed the complete supraspinatus tendon rupture. The humeral articular surface underneath the tendon showed a small focal full-thickness chondral defect grade IV according to the Outerbridge classification.⁸ Detailed inspection of the subacromial space demonstrated a perforated suture anchor tip on the inferior cortex of the lateral clavicle in direct opposition to the rupture site (figure 4). The chondral defect was carefully debrided, and the supraspinatus tendon was repaired in a double row technique (2×3.8 mm Y-knot RC all suture-anchor (ConMed Linvatec, Utica, New York, USA) medial and 2×4.5 mm knotless anchor ReelX (Stryker, Mahwah, New Jersey, USA) lateral). The clavicle anchor was removed via a separate incision through the previous scar over the lateral clavicle. Intraoperative stress testing of the AC joint showed no signs of horizontal or vertical instability. Postoperatively, the patient was instructed to use an abduction brace at 30° and physical therapy for passive mobilisation.

Figure 4.

Axial radiograph and intraoperative photo of the shoulder arthroscopy (A) with the tip of the suture anchor as the cause of tendon rupture (B).

Outcome and follow-up

The follow-up until 1 year was uneventful with little pain, full strength and range of motion symmetrically to the uninjured contralateral side.

Discussion

Over 50 surgical techniques have been described for the treatment of AC joint separation. Each technique has its own difficulties and particular complications. The most frequent complications include loss of reduction, persistent pain and fracture at the base of the coracoid or the clavicle. Other complications comprise over-reduction, infection, neurovascular injury and hardware migration.⁹ The herein presented case is, to our knowledge, the first report of complete supraspinatus tendon tear caused by a suture anchor tip. Iatrogenic tendon irritation and consecutive rupture is a known problem when using inadequate sized screws in other fields of orthopaedic surgery.^{10 11} Hardware associated subacromial impingement or rotator cuff injuries have been associated with the use of a hook plate for stabilisation of the AC joint or lateral clavicle fractures.⁶ This stems from the close anatomic proximity of the AC joint, the subacromial space and the rotator cuff. In our case, the tip of the suture anchor was penetrating the inferior cortex of the lateral clavicle directly over the tendon rupture site as seen during arthroscopy, and therefore suggestive as the cause of tendon rupture. The preoperative axial X-ray shows the close relation of the suture anchor and the subacromial space with the arm in adduction (figure 4). The humeral cartilage defect on the opposite of the anchor tip also underlines this theory. Associated rotator cuff injuries are frequently found in the course of an AC joint injury. Some authors recommend concomitant shoulder arthroscopy to address associated injuries at the time of AC joint stabilisation.^{12 13} Yet, this might result in an overtreatment of potentially negligible pathologies. In the presented case, associated glenohumeral injuries were excluded by an Arthro-MRI at the initial trauma evaluation. Additionally, the patient experienced an asymptomatic postoperative period of 8 months after the second surgery, suggesting no initial significant glenohumeral pathology. Suture anchors are frequently used for coracoclavicular ligament reconstruction, yet our patients also received an additional AC suture anchor.¹⁴ Usually, treating AC joint separations with a coracoclavicular reconstruction does not put the rotator cuff at danger. However, other techniques for AC joint stabilisation or lateral clavicle fracture repair like a lateral clavicle plate are more prone to endanger the rotator cuff. Interestingly, iatrogenic rotator cuff injuries after the use of fixation devices such as screws and plates for the fixation of lateral clavicle fractures are not yet described in the literature despite their close relationship with the subacromial space. Yet, subacromial spurs, comparable to the tip of the anchor, have been identified as risk factors for rotator cuff tears.¹⁵ While analysing our patient’s anatomy intraoperatively, we had the impression of a rather laterally located AC joint, which might have predisposed the patient to the described injury due to the even closer anatomic relationship of the suture anchor tip and the supraspinatus tendon. Most of anatomic shoulder classifications describe the acromion or glenoid shape, but do not assess the localisation and anatomy of the AC joint. In conclusion, this case presents a rare complication after AC joint stabilisation but highlights the close anatomic relationship of the AC joint and the rotator cuff. Thus, surgeons should be aware of this anatomic proximity when using anchors and screws in the lateral clavicle or AC joint.

Learning points.

• Rotator cuff injuries in young patients are very rare and predisposing causes have to be evaluated.

• Acromioclavicular (AC) joint injuries are frequently associated with rotator cuff tears.

• Depending on the individual anatomy, very close anatomic relationship between the AC joint and the rotator cuff can be encountered, thus close attention has to be paid when using anchors, plates and screws in lateral clavicle fractures or AC stabilisations.

Ethics statements

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