Table 1.
Analysis of the parameters affecting the development of heterotopic ossification
| Parameter | No. of patients | HO | HO rate (%) | P value (χ2) | P value (logistic regression firth’s correction) | |
| Gender | Male | 60 | 15 | 25 | ||
| Female | 24 | 0 | 0.0 | 0.007 | 0.081 | |
| ≤ 30 | 20 | 6 | 30.0 | |||
| Age | 31-55 | 39 | 8 | 20.5 | 0.067 | 0.205 |
| ≥ 56 | 25 | 1 | 4.0 | |||
| Extremity | Upper | 13 | 1 | 7.7 | ||
| Lower | 71 | 14 | 19.7 | 0.298 | 0.733 | |
| Defect size | Critical | 42 | 8 | 19.0 | ||
| Non critical | 42 | 7 | 16.0 | 0.776 | 0.997 | |
| Chronicity | > 1 yr | 33 | 4 | 12.1 | ||
| < 1 yr | 51 | 11 | 20.3 | 0.229 | 0.731 | |
| Infection | Yes | 30 | 4 | 13.3 | ||
| No | 54 | 11 | 20.3 | 0.420 | 0.451 | |
| Soft tissue defects | Yes | 9 | 3 | 33.3 | ||
| No | 75 | 12 | 16.0 | 0.200 | 0.287 | |
| Previous procedures | 1 | 56 | 8 | 14.3 | ||
| 2-3 | 28 | 7 | 25.0 | 0.227 | 0.315 | |
| Graft type | Autograft | 67 | 13 | 19.4 | ||
| Allograft | 9 | 0 | 0 | 0.463 | 0.663 | |
| No graft | 8 | 2 | 25.0 | |||
| Amount of rhBMP-7 | 1 vial | 75 | 14 | 18.6 | ||
| 2 vials | 9 | 1 | 11.1 | 0.576 | 0.629 | |
P values with the use of χ2 test and with the use of logistic regression model under Firth’s correction. HO: Heterotopic ossification; rhBMP-7: Recombinant human bone morphogenetic protein-7.