Fredericson MRI classification of medial tibial stress syndrome
Fredericson classification








Medial tibial stress syndrome.
The Fredericson MTSS classification follows a progression related to the extent of injury. This begins with periosteal oedema (grade 1), followed by progressive marrow involvement (grades 2 and 3), and eventually cortical stress fracture (grades 4a and 4b).
Case Discussion
MRI classification of medial tibial stress syndrome (MTSS) is an accurate way to correlate the extent of bone involvement with clinical symptoms, which leads to more accurate recommendations for rehab and return to sports activity.
The estimated delay in returning to impact activity based on this classification is 2:
Grade 1: 2-3 weeks
Grades 2-4a: 6-7 weeks
Grade 4b: 9-10 weeks or more