Table 1.
Subject characteristics*
| Subject characteristics | Overall (n = 880) |
Training set (614/887, 70%) |
Validation set (133/887, 15%) |
Test set (133/887, 15%) |
External Test Set (n = 96) |
|---|---|---|---|---|---|
| Age (years ± SD) | 33.1 ± 19.4 | 34.0 ± 19.9 | 31.8 ± 17.3 | 30.3 ± 18.5 | 31.7 ± 22.1 |
| Sex (females) | 395 (44.9%) | 275 (44.8%) | 60 (45.1%) | 60 (45.1%) | 40 (41.7%) |
| Malignant subtypes | 213 (24.2%) | 149 (24.3%) | 32 (24.1%) | 32 (24.1%) | 31 (32.3%) |
| Chondrosarcoma | 87 (9.8%) | 61 (9.9%) | 13 (9.8%) | 13 (9.8%) | 11 (11.5%) |
| Osteosarcoma | 34 (3.8%) | 24 (3.9%) | 5 (3.8%) | 5 (3.8%) | 7 (7.3%) |
| Ewing’s sarcoma | 32 (3.6%) | 22 (3.6%) | 5 (3.8%) | 5 (3.8%) | 5 (5.2%) |
| Plasma cell myeloma | 28 (3.2%) | 20 (3.3%) | 4 (3.0%) | 4 (3.0%) | 4 (4.2%) |
| NHL B cell | 26 (2.9%) | 18 (2.9%) | 4 (3.0%) | 4 (3.0%) | 4 (4.2%) |
| Chordoma | 6 (0.6%) | 4 (0.6%) | 1 (0.7%) | 1 (0.7%) | 0 (0%) |
| Benign subtypes | 667 (75.8%) | 465 (75.7%) | 101 (75.9%) | 101 (75.9%) | 65 (67.7%) |
| Osteochondroma | 228 (25.9%) | 160 (26.1%) | 34 (25.6%) | 34 (25.6%) | 16 (16.7%) |
| Enchondroma | 153 (17.4%) | 107 (17.4%) | 23 (17.3%) | 23 (17.3%) | 12 (12.5%) |
| Chondroblastoma | 19 (0.2%) | 13 (2.1%) | 3 (2.3%) | 3 (2.3%) | (2.1%) |
| Osteoid osteoma | 19 (0.2%) | 13 (2.1%) | 3 (2.3%) | 3 (2.3%) | 1 (1.0%) |
| Giant cell tumor of bone | 44 (4.7%) | 30 (4.6%) | 7 (5.0%) | 7 (5.0%) | 6 (6.2%) |
| Non-ossifying fibroma | 34 (3.9%) | 24 (3.9%) | 5 (3.8%) | 5 (3.8%) | 7 (7.3%) |
| Haemangioma | 12 (1.4%) | 8 (1.3%) | 2 (1.5%) | 2 (1.5%) | 3 (3.1%) |
| Aneurysmal bone cyst | 82 (9.3%) | 58 (9.4%) | 12 (9.0%) | 12 (9.0%) | 8 (8.3%) |
| Simple bone cyst | 24 (2.7%) | 16 (2.6%) | 4 (3.0%) | 4 (3.0%) | 5 (5.2%) |
| Fibrous dysplasia | 52 (5.9%) | 36 (5.9%) | 8 (6.0%) | 8 (6.0%) | 5 (5.2%) |
| Location | |||||
| Torso/head | 118 (13.4%) | 79 (12.9%) | 16 (12.0%) | 23 (17.3%) | 16 (16.7%) |
| Upper extremity | 234 (26.6%) | 166 (27.0%) | 28 (21.1%) | 40 (30.0%) | 29 (30.2%) |
| Lower extremity | 528 (60.0%) | 369 (60.1%) | 89 (66.9%) | 70 (52.6%) | 51 (53.1%) |
*Data is given as mean ± standard deviation; data in parentheses are percentages. The internal data set was split for training, validation, and testing 70%, 15%, 15%, respectively. The external test set obtained from a different institution was included for further independent testing. Malignant tumors included chondrosarcoma, osteosarcoma, Ewing’s sarcoma, chordoma, plasma cell myeloma, and b cell non-Hodgkin’s lymphoma NHL. Benign tumors included osteochondroma, enchondroma, chondroblastoma, osteoid osteoma, non-ossifying fibroma NOF, giant cell tumor, haemangioma, simple and aneurysmatic bone cyst, and fibrous dysplasia