Chondrolysis, osteonecrosis, and slip severity in patients with subsequent contralateral slipped capital femoral epiphysis.

BACKGROUND

Prophylactic pinning of the radiographically and clinically normal contralateral hip in a patient with a unilateral slipped capital femoral epiphysis remains controversial. The purpose of this study was to identify the prevalence of chondrolysis and osteonecrosis and the degree of slip severity in contralateral hips with a subsequent slipped capital femoral epiphysis to determine whether the outcome or complications on the contralateral side were greater than the risks of prophylactic pinning.

METHODS

The medical records of the patients operated on between 1993 and 2003 at a single hospital for treatment of a slipped capital femoral epiphysis were retrospectively evaluated. The severity and the chronicity of the slips were graded. Only children who initially had had a unilateral slip and had been followed for a minimum of twenty-four months or until skeletal maturity were included in the analysis for detection of a subsequent contralateral slip. Patients with more than twelve months of follow-up were included in the analysis for detection of osteonecrosis and chondrolysis.

RESULTS

Two hundred and twenty-seven patients had a unilateral slipped capital femoral epiphysis at the time of the primary admission. A subsequent slip developed in the contralateral hip of eighty-two children (36%) within a mean of 6.5 months. Eighteen of the contralateral slips were of moderate or severe severity, with a potential for a poor outcome due to a risk of osteoarthritis in the future. Osteonecrosis or chondrolysis, each an established complication with a poor long-term prognosis, developed in five of the patients with a subsequent contralateral slip.

CONCLUSIONS

The high prevalence of a subsequent contralateral slip (36%) and the potential complication (high slip severity) and established complications (osteonecrosis and chondrolysis) related to the contralateral slip indicate that prophylactic pinning of the contralateral hip in a patient with a unilateral slipped capital femoral epiphysis is safer than and preferable to observation and symptomatic treatment.