Heterotopic Ossification Classification

Heterotopic ossificaiton最常使用的分類為Brooker classificaiton:


Class I: Islands of bone within the soft tissue about the hip.
Class II: Bone spurs from the pelvis or proximal end of the femur, leaving at least 1 centimeter between opposing bone surfaces.
Class III: Bone spurs from the pelvis or proximal end of the femur, reducing the space between opposing bone surfaces to less than one centimeter.
Class IV: Apparent bone ankylosis of the hip.

Heterotopic Ossification Risk Factors

Risk Factors for Formation of Heterotopic Ossification

Patient factors

• Previous heterotopic ossification
• Hypertrophic osteoarthritis
• Male gender
• Ankylosing spondylitis
• Diffuse idiopathic skeletal hyperostosis (DISH)
• Previous trauma to the hip

Technique factors

• Surgical approach
• Surgical trauma to the gluteus medius/minimus
• Femoral fracture
• Postoperative hematoma
• Dislocation
• Infection

The anterolateral approach is associated with higher incidence of heterotopic ossification thant the posterolateral approach; however, the incidence of clinically significant heterotopic ossification is low with either approach.

The transtrochanteric approach has been associated with a higher incidence of heterotopic ossification.

Other studies demonstrated no significant difference in the rate of heterotopic ossification on the basis of surgical approach.

O'Rourke MR, Aggarwal A, Evans BG: Chapter 77. Late Complications and Management. Adult Hip. 2nd edition. p 1110.