Heterotopic ossifications following implant surgery--epidemiology, therapeutical approaches and current concepts

The pathophysiology of heterotopic ossification (HO) is still ill-understood. Several risk factors such as osteoarthritis, male gender and injury patterns like traumatic brain injury and severe soft tissue damage have been described. Furthermore, the pathophysiology of local and systemic factors has been investigated leading to an extended knowledge especially on the molecular level. Knowledge of the involved cell types and mediators led to the now widely used prophylactic and therapeutic strategies to prevent heterotopic ossifications. Out of these findings, the beneficial effects of NSAIDs and radiotherapy on HO prophylaxis have been proven for a number of indications such as total hip arthroplasty and acetabular surgery. However, there is little information about the potential effects on heterotopic ossifications around the elbow. Surgical treatment may be considered in some cases, but there are only limited indications. Generally, only clinically relevant bone formations should be resected. Following surgical resection, beneficial effects on range of motion and pain relief has been described. An accurate perioperative regimen is crucial and includes prophylactic medication. In combination with radiotherapy, low recurrence rates were described but there are still controversies about the optimal timing for surgical resection.