Heterotopic Ossification
Pronunciation: HET-er-oh-TOP-ik OS-ih-fih-KAY-shun
Also written as: HO
The pathological formation of bone in soft tissues—such as muscle, tendons, or periarticular structures—commonly complicating traumatic brain injury, spinal cord injury, or major joint surgery.
Full Definition
Heterotopic ossification (HO) is an abnormal process in which mature lamellar bone forms within soft tissues outside the skeleton. In PM&R, it is a recognized complication following TBI, SCI, burns, and total hip or knee arthroplasty, often leading to pain, swelling, and joint range-of-motion restriction. Early recognition is critical because HO can significantly impede rehabilitation progress. It is documented in physiatric notes, radiological reports, and surgical consultation records. Editors should not confuse HO with calcification; ossification produces histologically mature bone, while calcification refers to calcium salt deposition without bone architecture.
Usage
Usage note: Do not interchange with 'calcification'. 'Myositis ossificans' is an acceptable synonym only when the HO is confined to muscle tissue.
In Context
- "Heterotopic ossification was identified on plain radiograph of the left hip, prompting a referral to orthopaedic surgery for excision planning." — Physiatric progress note
- "Prophylactic indomethacin was prescribed to reduce the risk of heterotopic ossification following total hip replacement." — Post-operative rehabilitation protocol