Acromion fractures in polytrauma patients can be easily overlooked and the diagnosis is often delayed. When inadequately treated, these fractures may eventually lead to pain, limited range of motion, subacromial impingement, as well as rotator cuff injury (6).
Acromion fractures can be classified based on one of three classification systems. Ogawa and Naniwa classified acromion fractures based on their location in regards to the spinoglenoid notch, in which fractures lateral to the notch are Type 1 and fractures medial to the notch are Type 2 (7). Kuhn et al., on the other hand, used a classification algorithm based on fracture displacement. Accordingly, acromion fractures where classified as follows: Type 1, minimally displaced; Type 2, displaced without impacting the subacromial space; and finally Type 3, displaced with a reduction of the subacromial space (8). The AO/OTA classification system is based on the level of fracture comminution as well as fracture displacement (9). In our case report, the acromion fracture is classified as Type I according to Ogawa since the fracture is lateral to the spinoglenoid notch, Type 3 according to Kuhn since it was a displaced fracture resulting in reduction of the subacromial space and A1.2 according to AO/OTA since it is an extra-articular segmented fracture.
Since these fractures are rare, there is no suggested treatment guideline, and accordingly, there is no preferred or recommended surgical approach. Acromion fractures can be treated with K-wire fixation, tension band constructs, cannulated screws, or plate-and-screw constructs. Goss recommended the use of tension band technique and reported good results (1). Hill et al. used a plate for all acromion fractures in a study of 13 patients with good patient satisfaction, with only one case in which the plate was removed due to implant irritation (4). In addition, Zhu et al. recommended the use of perpendicular double-plate constructs with a locking system after evaluating this approach in a study including 9 patients with Type 3 acromion pedicle fracture with a displacement of more than 1 cm. In their study, Zhu et al. reported favorable results with good patient satisfaction rates and good Constant and DASH scores in their patients (10). In our case, we chose a combination of plate and cerclage wires, since this was an avulsion fracture of the lateral aspect of acromion with comminution.
When surgical intervention is indicated for fractures of the acromion is also a matter of debate. It is unclear if we should be more aggressive with such fractures and offer early surgical treatment, or we should take a more conservative approach and only intervene when the conservative therapy seems to be inadequate. A study by Kim et al. compared early and late surgical treatment of acromion fractures in 353 patients and found that all the patients who were surgically treated at an earlier time showed favorable pain and functional outcome scores, with all patients returning to their pre-fracture activities (11). Conversely, Hill et al. showed that the patients who underwent delayed treatment of acromion fractures were also able to return to their pre-injury function levels, similar to patients treated acutely (4). In our case, since the glenohumeral joint was under tension forces from the deltoid muscle which resulted in anterior subluxation of the joint, we opted for surgical treatment. We observed that after reducing the acromion fracture, these displacing tension forces of the deltoid muscle were subsequently neutralized, which in turn resulted in an anatomically articulating glenohumeral joint. Moreover, in an attempt to prevent any further injuries to the muscle itself, we opted for a minimally invasive approach to preserve the deltoid muscle integrity and function.
Unfortunately, our patient had major head trauma and was directly transferred to a neurological rehabilitation center, and as such, we could not assess the patient’s satisfaction or collect functional outcome scores.