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Heterotopic Ossification (HO) Calculator

Heterotopic ossification (HO), the development of abnormal bone in the soft tissue, is a rare but severely debilitating complication of burn injuries. The Boston-Harvard Burn Injury Model System developed a risk scoring system that can be used to predict HO at the time of hospital admission.

Burn Calculator

This Calculator is intended to be used at time of admission to determine an adult burn patient's risk of developing heterotopic ossification.

To use this calculator:

  1. Select burn size category represented as the percentage of the body surface area with second and third degree burns (%TBSA)
  2. Select areas with deep burns that are highly likely to require an operation for burn wound excision and skin grafting (auto graph)

The point sum produced can be matched with a percent risk in the table below. The average risk of HO is 3.06%.

Select percentage of body with second and third degree burns (%TBSA)*
Selection required to calculate risk.
Select areas with deep burns that are highly likely to require an operation for burn wound excision and skin grafting (autograft)
Heterotopic Ossification Risk
Point Sum Median Percent Risk Compared to Average Risk
0 0.04% < average risk
1 0.16% < average risk
2 0.18% < average risk
3 0.55% < average risk
4 0.88% < average risk
5 2.34% < average risk
6 1.69% < average risk
7 4.88% 1.6 times the average risk
8 9.77% 3.2 times the average risk
9 18.21% 6.0 times the average risk
10 34.96% 11.4 times the average risk
11 52.28% 17.1 times the average risk
12 70.16% 22.9 times the average risk
13 72.79% 23.8 times the average risk

This calculator was developed using data from the Burn Model System National Database. The records of 3,693 adult burn patients were analyzed for potentioal predictors of the development of heterotopic ossification (HO). It was found that total body surface area burned (TBSA), and the need for grafting of the head/neck, arm, and trunk weere associated with an increased risk of HO.

Schneider JC, Simco LC, Goldstein R, et al. Predicting Heterotopic Ossification Early After Burn Injuries: A Risk Scoring System. Ann SUrg. 2017;266(1):179-184. doi:10.1097/SLA.0000000000001841

The contents of this website were developed under a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (#90DP0035). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of website do not necessarily represent the policy of NIDILRR, ACL, HHS, and you should not assume endorsement by the Federal Government.