Which factor is more reliable considering prophylactic pinning of contralateral hip of unilateral SCFE patients?

BACKGROUND

This study evaluates the radiological parameters of developing subsequent contralateral slips in unilateral slipped capital femoral epiphysis (SCFE) patients at the time of initial presentation.

METHODS

The study group included the review of unilateral SCFE patients treated between June 2007 and August 2018. Age, gen-der, side, stability, posterior slope angle, grade of slip, modified Oxford bone age score (mOBAS), the Risser classification, and the ap-pearance of the triradiate cartilage were evaluated retrospectively. Data were analyzed between two groups: subsequent contralateral SCFE (SCFESC) patients that developed contralateral slip during follow-up and unilateral SCFE (SCFEU) patients that did not develop contralateral slip up to skeletal maturity. Descriptive statistics were used to compare risk factors between groups.

RESULTS

This study included 48 patients and 6 patients (12.5%) developed a SCFESC. Only mOBAS was significantly different be-tween groups. The mOBAS scores in SCFESC were 18 in 2 patients (33.3%), 19 in 4 patients (66.7%). The mOBAS scores in SCFEU were 18 in 1 patient (2.4%), 19 in 24 patients (57.1%), and >20 in 17 patients (40.5%). In the SCFESC group, all patients had a Risser score of 0 and all had open triradiate cartilage.

CONCLUSION

Patients with unilateral SCFE are at risk for SCFESC, and the mOBAS is the best predictor of risk assessment. We agree that mOBAS score of 16,17 or 18 patients' contralateral hips can be prophylactically pinned. We also suggest pinning or close screening of mOBAS 19 patients that some carry relatively high risk of subsequent contralateral slip.

Predicting subsequent contralateral slipped capital femoral epiphysis: an evidence-based approach

PURPOSE

The purpose of this study was to identify risk factors for developing a subsequent contralateral slipped capital femoral epiphysis (SCFE) and provide a prediction score to quantify risk of subsequent slip at the time of initial presentation.

METHODS

This retrospective study included patients that presented with a unilateral SCFE between 2006 and 2017. Chart and radiographic review were performed to collect demographic, clinical and radiographic risk factors. Descriptive statistics, univariate analyses and multivariate regression analysis were used to compare risk factors between patients that did or did not develop a subsequent contralateral SCFE.

RESULTS

This study included 183 patients and 33 patients (18%) developed a subsequent contralateral SCFE. Younger age at time of initial presentation, lower modified Oxford Score and smaller difference in epiphyseal-diaphyseal angle between both sides during index presentation were significant predictors of subsequent contralateral SCFE. Specifically, age ≤ 11 years, modified Oxford Score ≤ 20 and difference in epiphyseal-diaphyseal angle of ≤ 21° between both hips were predictive of a contralateral slip (Area Under the Curve = 0.78; p < 0.05). The presence of each risk factor increased the risk of subsequent contralateral SCFE and having all three risk factors increased the risk to 73%.

CONCLUSION

There is a significant risk of subsequent contralateral SCFE in patients with unilateral SCFE, and predictive risk factors include younger age, lower modified Oxford Score and smaller difference in epiphyseal-diaphyseal angle between the affected and unaffected hips.

LEVEL OF EVIDENCE

Level III.

Prophylactic pinning should be considered in patients at risk for slipped capital femoral epiphysis

Background: The use of prophylactic contralateral pinning for slipped capital femoral epiphysis (SCFE) remains controversial. This study evaluated the outcome of SCFE treatment and examined the use of prophylactic pinning.

Methods: The study included 44 patients (33 men, 11 women; 54 hips [right, 31; left, 23]), with mean age of 12.9 (7.3–29) years, who underwent treatment between 1986 and 2017, with follow-up for more than 6 months. Patients were divided into 3 groups: group 1 had bilateral SCFE at first presentation, group 2 developed contralateral side SCFE during follow-up, and group 3 had unilateral SCFE until final follow-up. Three patients who received prophylactic pinning were excluded. Univariate and multivariate logistic analyses were performed.

Results: Overall, 93% (50/54) of hips underwent positional reduction and in situ fixation and 7.4% (4/54) underwent open reduction. Mean follow-up period was 4.8 (0.5–25) years. Groups 1, 2, and 3 had 7, 3, and 31 cases, respectively. Sex, age, and follow-up period showed no significant differences among the groups. The Rohrer index was significantly higher in group 1, the affected side posterior sloping angle (PSA) was significantly higher in group 3, and the contralateral side PSA and percentage with endocrinopathy were significantly higher in group 2. In multivariate logistic analysis, age, sex, Rohrer index, affected side PSA, and endocrinopathy were significantly correlated with bilateral SCFE.

Conclusion: We recommend prophylactic contralateral side pinning in patients with risk factors of obesity, high PSA before slipping, and endocrinopathy. Careful observation until growth plate closure is required in patients without risk factors.