Acromial and scapular fractures after reverse total shoulder arthroplasty (rTSA) are an important cause of failure of reverse total shoulder arthroplasty.
These authors analyzed 4125 primary reverse total shoulders in 3,995 patients in an effort to identify risk factors for this complication and to compare the outcomes of patients with and without, acromial and scapular fractures.
Sixty-one of the 4,125 (1.77%) shoulders had radiographically identified acromial and scapular fractures at a minimum follow-up of 2 years, with the fractures occurring at a mean (and standard deviation) of 17.7 ± 21.1 months after surgery.
Ten patients had a Levy Type-1 fracture, 32 had a Type-2 fracture, 18 had a Type-3 fracture, and 1 fracture could not be classified.
Patients with acromial and scapular fractures were more likely to be female (84.0% versus 64.5% [p = 0.004]; odds ratio [OR] = 2.75 [95% confidence interval (CI) = 1.45 to 5.78]), to have rheumatoid arthritis (9.8% versus 3.3% [p = 0.010]; OR = 3.14 [95% CI =1.18 to 6.95]), to have rotator cuff tear arthropathy (54.1% versus 37.8% [p = 0.005]; OR = 2.07 [95% CI = 1.24 to 3.47]), and to have more baseplate screws (4.1 versus 3.8 screws [p = 0.017]; OR = 1.53 [95% CI = 1.08 to 2.17]) than those without fractures.
The X-ray below shows a superior screw at the junction of the scapular spine and the body of the scapula with an associated spine fracture resulting in inferior angulation and contact of the acromion with the tuberosity.
Patients with fractures had significantly worse outcomes than patients without fractures, and the difference in mean improvement between these 2 cohorts exceeded the minimum clinically important difference for the majority of measures.
Comment: Acromial and scapular spine fractures are serious complications of reverse total shoulder. The risk of these complications can be minimized by avoiding drill and screw penetration of the base of the scapular spine, by avoiding excess tension on the acromion, and by cautioning all patients to rehabilitate their shoulders slowly, giving the bone the opportunity to adapt to its new loading environment. Patients are cautioned to notify their surgeon if any pain arises in the area of the scapula so that the presence and management of a fracture or pending fracture can be defined. It is of note that in some cases, the earliest evidence of an acromial or spine fracture can be local tenderness that becomes evident before radiological changes occur. Finally, the long time between reverse total shoulder and the diagnosis of the fracture (17 months) in this series is noteworthy.
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