Descriptions of the 4 patients who developed postoperative avascular necrosis
| Characteristics | Patient 1 | Patient 2 | Patient 3 | Patient 4 |
|---|---|---|---|---|
| Age at presentation | 14 years | 12 years | 13 years | 10 years |
| Sex | Male | Female | Male | Female |
| Side of slip | Right | Right | Right (of bilaterial slips) | Left |
| Type of slip | Stable | Unstable | Unstable (left slip, stable) | Unstable |
| Grade | Moderate | Mild | Moderate | Mild |
| Time from presentation to operation | 28 hours | 72 hours | 19 hours | 36 hours |
| Manipulation | No | Yes | Yes | Yes, with skin traction |
| No. of screws | 2 cannulated | 1 ASINS | 1 cannulated | 1 cannulated |
| Range of motion, degrees | ||||
| FFD / forward flexion | 0/85 | 10/110 | 0/120 | 30/60 |
| Abduction /adduction | 40/40 | 20/25 | 30/15 | 30/10 |
| Internal/external rotation | 20/ 70 | −5/30 | 10/30 | 0/45 |
| Postoperative pain | Limping, no pain | Pain, stiffness | Minimal pain | Walking with crutches |
| Degree of avascular necrosis | Lateral aspect of head | Advanced OA changes | Flat head with sclerosis | Advanced OA changes |
| Additional procedures | 2 screws changed to a single screw, 1 day later | Proximal femoral triplane osteotomy | At fixation of left slip 2 yr postop, this screw was backed out a few turns because of head collapse | Derotation osteotomy of femoral diaphysis |
FFD = fixed flexion deformity; OA = osteoarthritic; postop = postoperatively