DDx
Parosteal OS
- bone is not continuous with cortex in MO
Aetiology
3% incidence in elbow joint trauma to some degree
Head + elbow joint trauma > 90%
Pathogenesis
Ectopic bone may ossify ligaments and capsule
- does not respect anatomical boundaries
- can completely envelope ulna nerve
- may form radio-ulnar synostosis
Usually in brachialis
Xray
CT
Show mature trabeculation
Define anatomical location
Surgery
Timing
Gartland
- negative Alk Phos and negative bone scan do not rule out recurrence after excision
- recommends do not resect till about 18/12
- well defined trabeculae on x-ray
Excision must be coupled with prophylaxis
Prophylaxis
Indomethacin
- 25 mg tds for 2 - 6 weeks
Radiotherapy
- 700 Gray single dose post operatively
Prognosis
A poor neurological recovery and spasticity associated with recurrence
Approach
Depends on site of ectopic bone
Options
- posterolateral
- anterolateral
- medial
Complications
Recurrence
Nerve injury
Beware post operative instability
