Table 1 Characteristics of benign cartilaginous tumours detected on MRI scan, split by radiological diagnosis of EC vs. ACT (n = 672)

Tumour size (in cm; mean ± SD)

1.6 ± 1.1

1.5 ± 0.9

5.1 ± 1.9

< 0.001**

Side

Left

312 (46.4)

301 (46.3)

11 (50.0)

0.829

Right

360 (53.6)

349 (53.7)

11 (50.0)

Bone

Distal femur

490 (72.9)

474 (72.9)

16 (72.7)

0.011

Proximal tibia

137 (20.4)

136 (20.9)

1 (4.6)

Proximal fibula

44 (6.6)

39 (6.0)

5 (22.7)

Patella

1 (0.1)

1 (0.2)

0 (0.0)

Location

Epiphysis

80 (11.9)

80 (12.3)

0 (0.0)

< 0.001

Epimetaphysis

70 (10.4)

65 (10.0)

5 (22.7)

Metaphysis

396 (58.9)

391 (60.2)

5 (22.7)

Metadiaphysis

32 (4.8)

27 (4.1)

5 (22.7)

Diaphysis

93 (13.9)

86 (13.2)

7 (31.9)

Patella

1 (0.1)

1 (0.2)

0 (0.0)

Location in Relation to Medullary Canal

Central

386 (57.4)

383 (58.9)

3 (13.6)

< 0.001

Peripheral

286 (42.6)

267 (41.1)

19 (86.4)

Periosteal Reaction

No

670 (99.7)

650 (100.0)

20 (90.9)

0.001

Yes

2 (0.3)

0 (0.0)

2 (9.1)

Medullary Oedema

No

666 (99.1)

646 (99.4)

20 (90.9)

0.014

Yes

6 (0.9)

4 (0.6)

2 (9.1)

Endosteal Scalloping

No

656 (97.8)

649 (99.9)

8 (36.4)

< 0.001

Yes

15 (2.2)

1*** (0.1)

14 (63.6)

Contrast Agent

No

591 (88.0)

582 (89.5)

9 (40.9)

< 0.001

Yes

81 (12.0)

68 (10.5)

13 (59.1)