Arthroplasty iSAWE 3

Question

A 66 year old man with ankylosing spondylitis has a stiff hip 6 months after total hip replacement.

Arthroplasty iSAWE 3, ap radiograph of the hip
AP radiograph of the hip. Image by Tdvorak, Wikimedia Commons, CC BY-SA 3.0.
  1. How is this classified?
  2. What are the risk factors and prophylaxis options?
  3. How is established disease managed?

Answer

Brooker classification

GradeDescription
IIslands of bone in the soft tissues
IISpurs with at least 1 cm between opposing surfaces
IIISpurs with less than 1 cm between surfaces
IVApparent bony ankylosis

Risk factors

  • Previous heterotopic ossification
  • Male sex, ankylosing spondylitis, DISH and hypertrophic osteoarthritis
  • Paget disease and head injury
  • Extensive soft tissue dissection

Prophylaxis

  • NSAIDs such as indomethacin for several weeks
  • Single dose radiotherapy within 24 hours before or 72 hours after surgery
  • Avoid NSAIDs with renal impairment or when bone healing is needed

Established disease

  • Excision for functional limitation in Brooker III and IV
  • Wait for maturation, usually 6 to 12 months
  • Prophylaxis after excision to prevent recurrence

Related pages

Author Contributions

Orthofracs team

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.