Heterotopic Ossification

Question 1

Where does heterotopic ossification usually occur in TBI and SCI?

Answer 1

TBI (traumatic brain injury)
hip>elbow>shoulder>knee

SCI (spinal cord injury)
hip>knee>elbow>shoulder

Question 2

What dose of indomethacin is used for heterotopic ossification?

Answer 2

75mg/day for 10 days to 6 weeks

Question 3

What is the radiative dose for HO?

Answer 3

700cGy4 hours preoperative or within 72hrs post-op

Question 4

What do ALP, radiographs, and bone scans show about heterotopic ossification?

Answer 4

Radiographs show sharp cortical margins, demonstrating lesion maturity
Bone scans can sometimes still be “hot” with maturity
ALP >250 can aid in diagnosis
ESR, CRP and CK can sometimes be elevated

Question 5

What are risk factors for the formation of heterotopic ossification?

Answer 5

High ISS, TBI, SCI, decubitus ulcers, anterograde femoral nail, femoral traction pin (>5mm), THA (anterior and direct lateral), acetabular fracture (extended iliofemoral>Kocher>ilioinguinal), TKA (notching, post-op mua), prolonged ventilator time, severe burns, amputations through zone of injury