MRI evaluation of growth plate closure rate and pattern in the normal knee joint.

The records of 320 patients (145 boys and 175 girls) who underwent magnetic resonance imaging (MRI) for the diagnosis of meniscal injury were reviewed. Growth plates of the distal femur and proximal tibia were examined, and the closure rate of the growth plates in each age group was evaluated. Imaging of the growth plates was low-signal intensity on T1-weighted MRI, high-signal intensity on T2-weighted MRI, and high-signal intensity on T2-gradient-recalled echo MRI. The disappearance rates of high-signal band on T2-gradient-recalled echo MRI in each age group were: 0% at < or = 11 years, 5% at 12 years, 34% at 13 years, 53% at 14 years, 94% at 15 years, and 100% at > or = 16 years. In the tibial growth plate on coronal MRI, the central portion had a tendency to close earlier than the peripheral portion. The results of this study suggest T2-gradient-recalled echo MRI should be used for diagnosis and follow-up of the growth plate. Furthermore, the fact that growth plate closure starts centrally suggests the possibility of using a tibial tunnel for anterior cruciate ligament reconstruction in young patients.