Table 1.
Patient demographics and univariate analysis
| Variable | Knee dislocation cohort (n = 88) | No HO cohort (n = 58) | HO cohort (n = 30) | p value |
|---|---|---|---|---|
| Age (mean [SD] in years) | 33.4 (10.5) | 31.8 (9.9) | 36.7 (10.7) | 0.031* |
| Sex (male) | 69 (78.4%) | 44 (76%) | 25 (83.3%) | 0.586 |
| Head injury | 2 (2.3%) | 1 (1.7%) | 1 (3.3%) | 1.00 |
| High-energy mechanism | 49 (55.7%) | 30 (51.7%) | 19 (63.3%) | 0.368 |
| Associated fractures | 23 (26.1%) | 14 (24.1%) | 9 (30%) | 0.612 |
| External fixator applied | 16 (18.2%) | 6 (10.3%) | 10 (33.3%) | 0.017† |
| Injury classification (Schenck) | ||||
| KD I | 19 (21.6%) | 16 (27.6%) | 3 (10%) | 0.099 |
| KD II | 2 (2.2%) | 1 (1.7%) | 1 (3.3%) | 1.00 |
| KD IIIL | 27 (30.7%) | 17 (29.3%) | 10 (33.3%) | 0.808 |
| KD IIIM | 22 (35%) | 18 (31%) | 4 (13.3%) | 0.076 |
| KD IV | 12 (13.6%) | 4 (6.9%) | 8 (25.7%) | 0.018 |
| KD V | 6 (6.8%) | 2 (3.4%) | 4 (13.3%) | 0.175 |
| Vascular injury requiring reconstruction | 6 (6.8%) | 2 (3.4%) | 4 (13.3%) | 0.175 |
| Fibular head fracture | 15 (17%) | 9 (15.5%) | 6 (20%) | 0.766 |
| Reconstructive surgery | 68 (77.4%) | 44 (76%) | 24 (80%) | 0.791 |
| PMC reconstruction or repair | 25 (28.4%) | 17 (29.3% | 8 (25.7%) | 1.00 |
| PLC reconstruction or repair | 39 (44.3%) | 21 (36%) | 18 (60%) | 0.043† |
| PCL reconstruction | 47 (53.4%) | 26 (44.8%) | 21 (70%) | 0.042† |
| ACL reconstruction | 53 (60.2%) | 36 (62.1%) | 17 (56.7%) | 0.652 |
| Time from injury to reconstruction (median [IQR] in days) | 242 (357.9) | 311.3 (411.4) | 136.2 (200.5) | 0.046‡ |
* Independent samples t-test; †Fisher’s exact test; ‡Wilcoxon rank sum test; HO = heterotopic ossification; KD = knee dislocation; PMC = posteromedial corner; PLC = posterolateral corner; PCL = posterior cruciate ligament; ACL = anterior cruciate ligament; IQR = interquartile range.