Does skeletal maturity predict sequential contralateral involvement after fixation of slipped capital femoral epiphysis?

BACKGROUND

The management of the uninvolved hip after fixation of unilateral slipped capital femoral epiphysis (SCFE) remains controversial. The purpose of this study was to determine the relationship of sequential contralateral slip to the initial patient presentation, specifically skeletal maturity.

METHODS

The medical records and radiographs for all patients who underwent fixation of unilateral SCFE between June 1996 and October 2003 were reviewed retrospectively. Data were gathered on age, sex, stability, chronicity, body mass index, modified Oxford bone age (mOBA), physeal slope angle, grade, and contralateral involvement as determined by need for fixation.

RESULTS

Seventy-one children underwent fixation of unilateral SCFE. At initial presentation, the triradiate cartilage was open in 43 patients and closed in 28 patients. There was no difference in the rate of contralateral involvement based on any measured parameter. Although not statistically significant, closure of the triradiate cartilage and increased mOBA were associated with lower rates of sequential slip progression. Only 1 patient with a mOBA greater than 22 had contralateral progression. The rate of contralateral slip was 23% when the triradiate cartilage was open. When the triradiate cartilage was closed, 93% demonstrated no sequential contralateral slip.

CONCLUSIONS

In this series, 23% of patients with open triradiate cartilage went on to contralateral slip, but all sequential slips were classified as mild. No studied variable proved to be a statistically significant predictor in this group of patients, including skeletal maturity. Further study to identify useful predictive factors would be beneficial to these patients, but our results question the need for prophylactic pinning in this population.

LEVEL OF EVIDENCE: Level IV.