Table I.

Disease specific inclusion criteria.

Perthes' disease

Slipped capital femoral epiphysis

Diagnosis made while skeletally immature. Any of the following radiological features within the femoral epiphysis: Flattening Sclerosis Fragmentation Collapse Re-ossification Features may be evident on plain radiographs, or MRI Resident within England, Scotland, or Wales Able to understand the study documentation No record of the following PRIOR to the first diagnosis Treatment for developmental hip dysplasia (not including double nappies) Chemotherapy for malignancy. Diagnosed sickle cell anaemia. Multiple epiphyseal dysplasia or spondyloepiphyseal dysplasia. A known coagulopathy Gaucher’s disease Same-sided hip fracture Hypothyroidism

Diagnosis made while skeletally immature. Radiological confirmation of displacement of the epiphysis relative to then metaphysis occurring at the proximal femoral physis. Treatment (surgery or activity restriction) following the diagnosis to stabilize the epiphysis. Able to understand the study documentation