MRI for paediatric flatfoot: is it necessary?

To determine the additional benefit of MRI for children with flatfoot deformity assessed with weight-bearing radiographs in a specialist paediatric orthopaedic unit. Patient cohort was obtained by searching the Radiology Information System for children referred for investigation of flatfoot. All patients with flatfoot on weight-bearing radiographs who had undergone MRI were included. Radiographs were classified by a consultant musculoskeletal radiologist as showing no underlying abnormality, talo-calcaneal coalition, calcaneonavicular coalition, accessory navicular or other abnormality. MRI studies were classified similarly by a different consultant musculoskeletal radiologist blinded to the radiographic findings. 33 males and 24 females were included (mean age 12.5 years; range 3-18 years). 24 had bilateral abnormality, so 81 feet were assessed. Radiographs showed no specific abnormality ( MRI is a valuable adjunct to weight-bearing radiography for investigating paediatric flatfoot deformity. MRI is of value in the assessment of paediatric flatfoot, additional diagnostic information to radiography being identified in 23.5% cases, while in 60.8% of cases for which radiographs provided no specific diagnosis MRI confirmed no underlying abnormality.