Challenges and advances in the management of heterotopic ossification in total hip arthroplasty

Heterotopic ossification is the formation of ectopic lamellar bone, predominantly in muscle and soft tissues, without attachment to the periosteum. 1 The condition was first described as "paraosteoarthropathy" by French physicians Dejerne and Ceiller, as a consequence of traumatic paraplegia in patients injured during the First World War. 2 It remains a recognized cause of morbidity in military personnel and a major cause of disability in the civilian population following orthopaedic surgery, trauma, burns, and neurological injuries. [3][4]4][5][6] The reported prevalence of heterotopic ossification is 8% to 90% following total hip arthroplasty (THA), 17% to 100% following acetabular fractures, 0.2% to 4% following burn injuries, and 18% to 50% following traumatic brain injury. 4,[7][8]][9][10][11] Patients present with variable levels of disability owing to pain, joint contractures, muscle loss, joint ankylosis, or fractures from disuse osteopenia. 3,4,12espite recent advances across several clinical and research fields in orthopaedics, the pathophysiology of heterotopic ossification has not yet been fully determined. [13][14]4][15] The proposed mechanism of heterotopic ossification involves soft-tissue trauma, followed by an influx of inflammatory cells, and downstream signalling leading to osteogenic and chondrogenic activation. [16][17]7][18][19] Understanding the key challenges and recent advances in the pathophysiology, risk factors, and management strategies of heterotopic ossification is essential for optimizing patient outcomes, reducing long-term morbidity, and guiding further research in this field.