title: Heterotopic ossification after reverse total shoulder arthroplasty.
abstract: OBJECTIVE
  Heterotopic ossification (HO) occurs after arthroplasty, especially total hip arthroplasty. In this study we describe the incidence, evolution, morphology and clinical consequences of HO following reverse shoulder arthroplasty.
  
  
  METHODS
  This is a single-centre retrospective study of 132 consecutive patients who received a Delta III or Delta Xtend reverse total shoulder arthroplasty between 2006 and 2013 for the treatment of cuff tear arthropathy. There were 96 women and 36 men. Their mean age at the time of surgery was 69 years (49 to 89) and the mean follow-up was 36 months (12 to 84). The incidence, evolution, morphology and clinical consequences of HO using the Constant-Murley score (CS) were analysed. A modified Brooker classification of HO of the hip was used.
  
  
  RESULTS
  HO was seen in 39 patients (29.5%). A total of 31 of these patients (81.6%) began to develop HO by three months post-operatively. According to the Hamada classification, 11 patients had grade 1a, eight had grade 1b, six had grade 1c and 14 had grade 2 HO. The HO evolved over a mean of 8.3 months (3 to 21). Patients with HO had a lower mean CS at three (p = 0.017), six (p < 0.001) and 12 months (p < 0.001) post-operatively. HO was not associated with notching (p = 0.675).
  
  
  CONCLUSIONS
  HO after reverse shoulder arthroplasty is a non-progressive condition without long-term clinical consequences. Only grade 2 HO is clinically relevant with a negative effect on the function of the shoulder during its development. Cite this article: Bone Joint J 2016;98-B:1215-21.
authors: Ghent University Hospital, 185 De Pintelaan, 9000 Ghent, Belgium.
authors: B
authors: B
authors: Verhofste
authors: Ghent University Hospital, 185 De Pintelaan, 9000 Ghent, Belgium.
authors: T
authors: T
authors: Decock
authors: Ghent University Hospital, 185 De Pintelaan, 9000 Ghent, Belgium.
authors: A
authors: A
authors: Van Tongel
authors: Ghent University Hospital, 185 De Pintelaan, 9000 Ghent, Belgium.
authors: L
authors: L
authors: De Wilde
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects* / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009999:Ossification, Heterotopic / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D017678:Sex Distribution
keywords: Cuff tear arthropathy; Heterotopic ossification; Notching; Reverse total shoulder arthroplasty