Heterotopic ossification of the long head of the triceps after reverse total shoulder arthroplasty.

BACKGROUND

Heterotopic ossification (HO) around shoulder arthroplasty is a frequent finding with unclear clinical relevance. This study evaluated the incidence, relevance, and predisposing factors of HO in the long head of the triceps tendon after reverse shoulder arthroplasty.

METHODS

Retrospective chart review was conducted to identify patients who had a reverse shoulder arthroplasty performed between 2008 and 2012. Patient demographics, implant types, and diagnoses were noted. Three fellowship-trained shoulder/elbow surgeons independently evaluated postoperative Grashey radiographs using a novel classification system.

RESULTS

Within a 164-patient cohort, the overall HO rate in the long head of the triceps tendon was 61.6%; 23.2% of osteophytes were considered impinging, 14.6% had notching, 14.0% were free-floating, and 3.0% appeared ankylosed. Although not statistically significant, revision surgery had a higher rate of HO (68.3%) compared with primary surgery (59.4%). There was no difference in HO rates between diagnoses or implant types. Male and female HO rates were 74.0% and 56.1%, respectively (P = .0304). Between patients with and without HO, forward elevation was 121° compared with 133° (P = .0087) and external rotation was 19° compared with 25° (P = .0266); however, HO size did not significantly affect motion.

CONCLUSIONS

Using our novel classification scheme, HO was a common finding in this series. Men had a higher rate of HO formation, and HO formation was associated with worse postoperative motion. Further study is needed to fully characterize the clinical implications of HO involving the long head of the triceps tendon and to explore potential preventive measures.