A 58-year-old woman was referred to our clinic with a large, indented tear in the right rotator cuff.

Her medical history is complicated, including previous myocardial infarction, Crohn’s disease, hepatitis C, hypertension, depression, chronic obstructive pulmonary disease, and smoking a pack of cigarettes a day for 30 years. She was referred for a rotator cuff pathology examination, but between this time and her first visit (approximately 3 months), her right shoulder suffered minor trauma, during which she felt a "pop" while dressing . Follow-up imaging at her initial visit showed a displacement of the acromion fracture (Figure 1). Before this minor trauma, an external MRI was performed, which confirmed her long-standing massive rotator cuff tear, but it also showed her anatomical position before the injury (Figure 2).

The patient's clinical evaluation revealed pseudoparalysis of the right shoulder and diffuse tenderness throughout the joint. She could not tolerate the passive range of motion and reported that her right arm was unable to perform activities of daily living. Her condition was severely incapacitated, and her acute deterioration was attributed to the separation of her operating system. The patient's previous non-surgical treatments have failed, including physical therapy, NSAIDs, and rotator cuff injections. Now that she is functionally weak, what are the surgical options?

The patient's surgical treatment included open upper capsule reconstruction (SCR), open reduction and internal fixation of the acromion (ORIF), and open suprathoracic biceps tenodesis.

The patient was placed in a beach chair, and preoperative intermuscular nerve block was performed under general anesthesia. A band incision is made on the inside of the fracture site, and a longitudinal split is performed on the triangular trapezoidal fascia at the entrance area of ​​Neviaser to expose the fracture site. The fractured acromion was retracted to the outside, and the long head of the biceps brachii tendon was cut to perform lateral tenodesis, and the rotator cuff laceration with a large number of contractions was visualized to enter the glenohumeral joint. The large nodules and the footprint on the upper glenoid are prepared by removing all remaining fibrous tissue. The suture anchors consist of three 3.9 mm opener suture anchors (Arthrex) for the glenoid and two 4.75 mm SwiveLock anchors (Arthrex) in the nodules for SCR, which can then be easily placed by "predetermining" Open acromion fracture under direct visualization (Figure 3). The suture thread passes through the allogeneic dermal graft in turn, and shuttles the allograft into the joint, from the upper glenoid to the upper nodule. A lateral row configuration was added to compress the lateral graft onto larger nodules throughout the footprint (Figure 4). The intact subscapularis muscle was sutured to the SCR graft, and one of the nodule anchors was used to fix the long head tendon of the biceps and close the triangular trapezoid fascia.

Then expose the scapula through the same skin incision, further exposing the acromion fracture site. A large amount of fibrin material was encountered at the fracture site, and it was removed to form clean, bleeding bone edges on both sides of the fracture. By placing two #5 FiberWire sutures (Arthrex) into the deltoid muscle-acromial bone-tendon junction, the free segment is reduced. While keeping the free segment in an anatomical position, the pre-formed acromion plate was placed above the acromion, and the free segment was fixed with a combination of a locking screw and a medial non-locking screw (Acumed LLC). A 3.5 mm reconstruction steel plate (Stryker) was placed vertically behind and above the acromion to reinforce the upper steel plate. FiberWire sutures are tied around the upper steel plate to provide further repair reinforcement (Figure 5).

The osteoinductive bone allograft material is placed at the fracture site. Intraoperative fluoroscopy confirmed the anatomical reduction of the fracture and the proper screw length and position (Figure 6). The wound is flushed and properly closed. After the operation, the patient received a delayed SCR program and was prohibited from active exercise for 3 months. She was last seen during a visit one year after surgery and was in good condition. Her fixation is intact, she actively raises it forward to 90° and actively rotates it to 40°.

The acromion is an anatomical variation that occurs in approximately 3.4% to 7% of individuals and is caused by failure of acromion ossification and fusion during development. According to reports, patients with acromion muscles have a certain degree of inherent instability and may be at risk for bone and joint degenerative changes or symptomatic pain. Symptomatic cases have been described in the literature, and treatment methods, including os resection, decompression, and internal fixation, have reported varying success rates. When the deltoid stop can be retained, Os resection is a reasonable alternative to internal fixation. However, in the case of significant displacement, the insertion of the deltoid muscle may be affected.

This report describes a case of an acromion fracture that was severely displaced after a minor trauma with a potential, irreparable, massive rotator cuff tear. The senior author's decision to conduct SCR and ORIF at the same time is multi-factorial. First, because a large number of the patient’s deltoid muscles are attached to the displaced fracture mass, os resection alone is not feasible. Secondly, ORIF alone may put the patient at risk of failure of the fixation, because in the case of a defective rotator cuff, the upper shoulder will produce high mechanical stress. Finally, considering the space available through her displaced acromion, the SCR is considered relatively easy to access. It is worth noting that ORIF plus reverse shoulder arthroplasty was also considered, but again, this will bring new mechanical stress to the upper shoulder and may put her at risk of early fixation failure.

The acromion is a relatively common anatomical variation, but it rarely becomes pathological. Here is a unique case report of acromion displacement that occurred in the event of a huge, irreparable rotator cuff tear. Proper entry of the displaced fragments into the subacromial space allows simultaneous SCR and internal fixation of the displaced fragments. This patient has a good functional prognosis one year after surgery, with anterior elevation to 90° and external rotation to 40°. Although this case highlights the unique surgical issues of a single patient, the anatomical considerations are broad and apply to all pathologies of the shoulder.

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