[Radiological risk factors of bilaterality in unilateral slipped capital femoral epiphysis].

The aim of the study was to determine radiological risk factors of development of secondary contralateral slip in patients with primary unilateral slipped capital femoral epiphysis (scfe). The material consisted of 115 patients operated because of scfe in the Institute of Orthopaedics and Rehabilitation at the University of Medical Sciences of Poznań in 1968-1991. There were 75 boys (65%) and 40 girls (35%) at the mean age 12.8 years. The retrospective analysis showed that contralateral slip developed more often in patients with more vertical orientation of subcapital growth plate (with Alsberg angle less than 60 degrees). The neck-shaft angle, slip angle, slip direction and negative Klein's sign has no prognostic value according to development of secondary contralateral slip. More than 1/3 of the patients with unilateral scfe developed silent, subclinical contralateral slip. In most of that patients radiological signs of preslip stage of contralateral slip can be observed (positive Klein's sign, pathological neck-epiphyseal angle).