Preoperative assessment of idiopathic scoliosis in adolescent and young adult with three-dimensional T2-weighted spin-echo MRI.

PURPOSE: To compare tridimensional (3D) T2-weighted spin-echo MRI and CT for minimal pedicle width measurements in the preoperative assessment of adolescent idiopathic scoliosis (AIS) in adolescent and young patients. MATERIALS AND METHODS: A total of 22 adolescents/young patients suffering from AIS were retrospectively included. There were 18 females and 4 males with a mean age of 15.3±2.3 (SD) years (range: 11-21years). Preoperative lumbar spine MRI and CT examinations of the 22 patients were reviewed by two independent readers who measured the minimal width of 259 pedicles. Inter-reader agreement for CT and MRI was assessed using intra-class correlation coefficient (ICC). Intra-reader agreement and relative differences in measurements between MRI and CT were also assessed for each reader. RESULTS: Inter-reader agreement was excellent (ICC≥0.8) for both CT and MRI. Relative differences in measurements between CT and MRI was 10.3% for reader 1 and 9.4% for reader 2. CONCLUSION: 3D T2-weighted spin-echo MRI underestimates minimal pedicle width by only 9.4 - 10.3% compared to CT. 3D T2-weighted MRI appears as a valuable alternative to CT for preoperative measurements of vertebral pedicles in AIS.

Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years' follow-up: a 222 case series.

INTRODUCTION: Slipped capital femoral epiphysis (SCFE) can lead to hip impingement, more or less rapidly depending on initial slippage severity and on surgical technique. Various surgical options are applicable, including in situ fixation (ISF). The aim of the present study was to look for long-term signs of radiological impingement in hips treated for SCFE by IFS, in order to identify a slip threshold beyond which impingement more regularly appears. MATERIAL AND METHODS: A multicenter retrospective study assessed the clinical and radiological evolution of patients operated on by ISF for SCFE, with a minimum 10 year's follow-up. Coxometric analysis of postoperative and last follow-up radiographs was performed. Functional outcome was assessed on Oxford hip score and radiographic osteoarthritis on the Tönnis classification. Alpha angle was measured on lateral views to highlight hip impingement. RESULTS: Two hundred and twenty-two hips were included, with a mean 11.2 years' follow-up. Mean age at diagnosis was 12.8 years. Mean preoperative Southwick angle was 38.8°, with 43% of hips at stage I, 42% at stage II and 15% at stage III. At latest follow-up, mean Oxford score was 14.86, with 88% of hips rated Tönnis 0 or I. Only 15 cases of impingement were diagnosed. There seemed to be a non-significant trend for hip impingement in SCFE exceeding 35°. CONCLUSION: ISF led to hip impingement in moderate to severe initial epiphyseal displacement. However, in smaller displacement, the consequences were milder, with perfectly satisfactory function scores and no clinical or radiological evidence of impingement. The threshold seemed to be around 35° slippage, beyond which other surgical options than ISF should be considered. Thus, it seems reasonable to propose isolated ISF in SCFE<35° and to treat symptomatic impingement by surgery in stage II slips.