Troublesome heterotopic ossification and stroke: Features and risk factors. A case control study.

Primary Objective: To determine the features of stroke-related HO in a large sample of patients and to assess if HO risk is increased by haemorrhagic stroke.

Research Design: A case control study (risk factor of a rare event using retrospective analysis).

Methods And Procedures: Sixty-one patients with stroke-81 troublesome HOs-were included, each was matched with four controls, i.e. 244 patients with no HO after stroke. Matching criteria were age (±3.5 years) and sex. Data recorded were time from stroke to surgery, ischaemic or haemorrhagic stroke and presence of HO risk factors.

Main Outcomes And Results: Mean age at time of stroke = 46.02 ± 11.4 years (15.9-76.3) for the case sub-group. Time from stroke to surgery = 23.4 ± 27.8 months (3.6-150.0). There was a significant relationship between haemorrhagic stroke and HO development (OR = 3.01; 95% CI = 1.14-7.98; p < 0.05), but not for ischaemic stroke. This became non-significant when all matching and risk factors were included in the model (adjusted OR = 1.98; 95% CI = 0.60-6.54; p = 0.26).

Conclusion: Haemorrhagic stroke appears to increase the risk of HO development. Further studies are required to determine if this risk factor is independent from other comorbid factors.