[Persistent coxalgia in the child. The value of magnetic resonance]

This study was aimed at assessing the Magnetic Resonance (MR) features of persistent hip pain in children. Twenty-six patients aged 1.6 to 15.2 years (mean: 6.5 years) were clinically selected for the study; at clinics, all patients had persistent hip pain after 10 days' therapy. All patients were examined with radiography, US and MRI at 0.5 T. SE T1-weighted sequences, with and without fat suppression (FS), SE T2-weighted and gradient echo (GE) T1-weighted-like (T1*) sequences were acquired on the coronal plane. Slices were 5 and 3 mm thick on SE and GE T1* sequences, respectively. Morphology and signal intensity of epiphysis, growth plate and metaphysis were prospectively studied with MRI. Clinical and/or imaging follow-up (3 months) was the reference standard in our study. Final diagnoses were: no evidence of alteration (n = 3), transient synovitis (n = 6), rheumatic fever (n = 3), Perthes' disease (n = 7), Meyer's dysplasia (dysplasia epiphysealis capitis femoris, DECF) (n = 2), early slipped capital femoral epiphysis (n = 2), incomplete fracture (n = 1), extraarticular cause of pain (muscular abscess, osteomyelitis) (n = 2). In 23 of 26 patients MRI confirmed clinical, radiographic and US findings. MRI was particularly helpful in making an unquestionable diagnosis in the other 3 cases; in a patient with suspected slipped capital femoral epiphysis MRI revealed an incomplete fracture, in a patient with suspected Meyer's dysplasia MRI revealed early Perthes' disease and finally in a patient with suspected transient synovitis MRI revealed Perthes' disease. To conclude, MRI allows the condition causing persistent hip pain to be assessed and accurately depicted, integrating clinical, radiographic and US findings and in some cases also changing diagnosis and therapy.