Myositis Ossificans

 

Elbow Myositis OssificansElbow Myositis Ossificans

 

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

 

Elbow HO

 

CT

 

Show mature trabeculation

Define anatomical location

 

Elbow CT Posterior HOElbow CT HO Anterior

 

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

 

Elbow HO Excision PreopElbow HO Excision Post op

 

Complications

 

Recurrence

 

Nerve injury

 

Beware post operative instability

 

Elbow Post HO Excision