Clinically or radiographically identified predisposing conditions for OA of ipsilateral, surgically resected joint in patients with hip and knee OA
| Hip OA | Knee OA | |
|---|---|---|
| Number (%) idiopathic OA | 238 (58.3) | 251 (66.6) |
| Number (%) secondary OA | 170 (41.7) | 126 (33.4) |
| caused by | ||
| DDH2-150 | 102 (25.0) | — |
| SCFE† | 29 (7.1) | — |
| Perthes disease | 1 (0.3) | — |
| avascular necrosis | 22 (5.4) | 1 (0.3) |
| osteochondritis | 0 (0.0) | 3 (0.8) |
| chondromatosis | 0 (0.0) | 2 (0.5) |
| haemorrhagic diateses | 0 (0.0) | 1 (0.3) |
| infection | 5 (1.2) | 11 (2.9) |
| trauma | 11 (2.7) | 108 (28.7) |
↵2-150 DDH developmental dysplasia of the hip. †SCFE slipped capital femoral epiphysis.