Meyer dysplasia is a rare condition that affects the femoral epiphysis in young children. This developmental disorder of the hip is characterized by delayed, irregular ossification of the femoral epiphyseal nucleus. Onset usually occurs in the second year of life, and the disorder usually disappears by the end of the sixth year. Harel and colleagues review the features of this dysplasia and describe five cases that were initially misdiagnosed.

The five cases included four males and one female who ranged from nine to 48 months of age at the time of presentation. Each child had a history of acute onset of limping of two to 30 days' duration. Three of the children had decreased range of motion on physical examination, and one patient had a fever. The erythrocyte sedimentation rate was elevated in two patients. The initial diagnosis was osteomyelitis in two children and Perthes disease in three children.

Radiographs of the hips revealed epiphyseal changes compatible with Meyer dysplasia. Two children had unilateral involvement, and three had bilateral involvement. Bone scans were normal in all five cases. Magnetic resonance imaging was performed in one child and revealed multiple centers of ossification and no evidence of ischemia or edema. In all patients, limping resolved within one to three weeks without specific treatment.

The authors note that Meyer dysplasia is most often bilateral. Meyer, in 1964, reported that this disorder occurs bilaterally in 42 percent of patients. In contrast, 7 percent of patients with Perthes disease have bilateral involvement. Previous studies indicate that boys are affected five times more often than girls. Patients show continuous improvement, with steady unification and growth of the epiphysis, usually over a three-year period.

Meyer dysplasia likely represents a physiologic variant of ossification of the femoral head. In most cases, the disorder is asymptomatic and is discovered incidentally on radiographs obtained for other reasons. Radiographic features include radiolucent defects in the femoral head and fragmentation of the femoral head. The authors point out that epiphyseal dysplasia and hypothyroidism should be included in the differential diagnosis whenever bilateral changes are visualized on plain radiographs of the hips. Bone scans are normal in patients with Meyer dysplasia. The authors note that Meyer dysplasia may be easily confused with more serious conditions such as osteomyelitis and Perthes disease, but knowledge of this condition can prevent unnecessary hospitalization and treatment.