Bilaterality in slipped upper femoral epiphysis
The frequency of slipping and osteoarthritis of the contralateral hip was recorded in 260 patients with slipped upper femoral epiphysis between 1910 and 1960. Twenty-three of these patients (9%) had primary bilateral slipping, 32 (12%) had a contralateral slip diagnosed later during adolescence and a further 104 (40%) had signs of contralateral slipping at follow-up 16 to 66 years later, giving a