MRI in idiopathic, stable, slipped capital femoral epiphysis: Evaluation of contralateral pre-slip

Abstract

Abstract:PurposeEarly diagnosis and treatment of slipped capital femoral epiphysis (SCFE) is important to prevent slip progression and avoid complications. We sought to determine if MRI findings in patients with unilateral SCFE could indicate ‘pre-slip’ or predict future SCFE in the contralateral hip.MethodsA prospective study evaluated patients with unilateral SCFE over a two-year period. MRI of the asymptomatic hip was performed within the perioperative period. Patients were followed with radiographs until a contralateral slip occurred or until physeal closure. Demographics, clinical stability, severity, posterior slope angle (PSA), modified Oxford Bone Score (mOBS) and patency of the triradiate cartilage were recorded and statistical analysis performed.ResultsIn all, 33 of 54 patients with unilateral SCFE were enrolled into the study. In all, 29 (87.8%) had complete follow-up. Five of the enrolled patients (15.2%) developed a sequential slip requiring in situ pinning. Six of 33 (18.2%) patients had positive MRI findings: four of which proceeded to sequential SCFE and two which did not. One sequential slip had a negative MRI. PSA predicted 1/11 sequential slips (sensitivity 9.09%, specificity 81.4%, positive predictive value (PPV) 11.1%, negative predictive value (NPV) 77.8%) and mOBS predicted 5/11 sequential slips (sensitivity 45.5%, specificity 93%, PPV 62.5%, NPV 87%). An open triradiate cartilage was present in 8/11 patients with sequential slips (sensitivity 72.7%, specificity 81.4%, PPV 50%, NPV 92.1%).ConclusionMRI findings consistent with ‘pre-slip’ were present in 66.7% of patients who developed a sequential SCFE. Further study on the utility/sensitivity of MRI in predicting sequential SCFE is warranted.Level of EvidenceII, diagnostic

Probability analysis of sequential SCFE (PASS score)

“…A previous study sought to utilize MRI to evaluate contralateral SCFE upon presentation. 7 This study enrolled 33 patients from 2011 to 2013. In this study, six of 33 patients had positive MRI findings suggestive of a pre-slip.…”

“…Many parameters have been proposed as predictive factors for contralateral, sequential SCFE including: skeletal maturity, 5 body mass index (BMI) 6 and magnetic resonance imaging (MRI) pre-slip parameters. 7 Femoral head/neck morphology, especially the posterior sloping of the epiphysis, has also been implicated. 8 - 10 Previous studies have shown that the posterior sloping angle (PSA) of the physis on an axial radiograph is significantly higher in patients who progress to contralateral, sequential SCFE.…”

Surgeon Preference for Prophylactic Contralateral Fixation in Slipped Capital Femoral Epiphysis (SCFE) Patients: A Nationwide POSNA Survey Study

“…In addition, surgeons favored select measurements and frequently utilized advanced imaging. MRI, the most popular alternative among survey participants, 23 and CT scans 24 have been suggested in many studies as adjuncts or alternatives to standard radiography, which remains the first choice for SCFE. However, from this survey, it cannot be determined whether surgeons commonly order advanced imaging in practice or if they would like to consider MRI and CT as an alternative or supplement to radiographs in the future.…”

Classic Slipped Capital Femoral Epiphysis: A Case Report

“…Twenty five percent of SCFE are bilateral. 13,14,15,16 Suspect SCFE in an obese, adolescent boy during the rapid growth spurt that has hip, thigh, or knee pain.…”

“…14 Although MRI still has limited use in making the diagnosis of SCFE, small studies indicate MRI may be useful in determining if an occult or pre-slip is present in the contralateral hip with a sensitivity of 80% and a specificity of 92%. 15,16 Thus, once the diagnosis of SCFE is made, the patient should not bear any…”