Comparison of the Femoral Head Height/neck Length Ratio between the Unaffected Hip of Patients with a Unilateral Slipped Femoral Head and the Hips of Individuals without a Slipped Femoral Head.

Objective - To compare the head/neck ratio on the contralateral side of patients with a unilateral slipped capital femoral epiphysis (SCFE) with control individuals. Methods - Seventeen patients who were followed up at the Department of Orthopedics and Traumatology, Federal University of São Paulo, Brazil, between 1985 and 2007, were assessed. The control group consisted of 34 individuals from the same place who were matched for gender and age, with a history of trauma that necessitated pelvic radiography. The femoral head height and femoral neck measurements were made using simple pelvic radiography in accordance with the criteria of Bleck (1983), on both sides in the control group and on the contralateral hip in the patients. Nonparametric statistics were used, with a p-value ≤ 0.05. Results - There was no difference in the distribution of age, gender, body mass index and bone age between the groups. The head/neck ratio on the right and left side in the controls did not differ (p = 0.64). However, the head/neck ratio from the contralateral hip of the patients with SCFE was significantly lower than that of the control group (p = 0.00). Conclusion - The significantly lower head/neck ratio in the patients with epiphysiolysis could be indicative of a risk of SCFE.