Acromion and Clavicle Stress Fractures After Reverse Total Shoulder Arthroplasty Reflect Failure to Address Osteoporosis: A Case Report and Literature Review.

Abstract

The exponential increase in the rate of reverse total shoulder arthroplasty (RTSA) has been accompanied by a rise in complication rates of this procedure. Of these, peri-prosthetic stress fractures can be particularly problematic due to their potential to cause significant impairment of shoulder function. Despite the association between these stress fractures and osteopenia/osteoporosis, pre-operative bone density assessment is not standard practice for elective RTSA. We report the case of a 68-year-old female patient who, at eleven weeks after elective RTSA (for rotator cuff-tear arthropathy), experienced a non-traumatic stress (insufficiency) fracture of the acromion process of the ipsilateral scapula. Thirteen weeks later, new-onset pain occurred with minimal shoulder use, and a midshaft clavicle stress fracture was detected. She was then diagnosed and treated for osteoporosis, vitamin D deficiency, and hypothyroidism. An ultrasound-based bone-growth stimulator was used to treat both fractures, but only the acromion fracture healed. The clavicle fracture became a 100% displaced chronic non-union. However, the patient felt that surgical fixation of the clavicle fracture would not provide a significant benefit. At 1.5 years after the RTSA, she was moderately satisfied with her shoulder function and highly satisfied with pain reduction, and no additional surgery was required. This is the first reported case describing a patient with acromion and clavicle stress fractures occurring in association with ipsilateral RTSA. We also review the literature of cases with clavicle stress fractures in association with RTSA and highlight key findings: (i) the prevalence of osteoporosis in the population undergoing shoulder arthroplasty is high and (ii) performing shoulder arthroplasty on patients with poor bone quality presents multiple challenges that are underappreciated. This case underscores the importance of pre-operative bone density/health screening to mitigate stress fracture risk after RTSA.