Stress Fracture in Posterior Aspect of the Tibia

PURPOSE: To determine correlation between stress fracture of the posterior tibia and flexor digitorum longusmuscle injury caused by athletic or sporting activity during adolescence. MATERIALS AND METHODS: Eleven casesdiagnosed as stress fracture after X-ray and MR imaging of the lower leg were reviewed. With regard to eachfracture, the following features were noted: age, sex, and athletic or sporting activity of the patient, and site.Using MR imaging techniques, axial and sagittal T1 and T2 weighted images were obtained in all cases and T1-GdDTPA images in seven. RESULTS: The activities undertaken were running (n=3), football (n=2), ballet (n=2),taekwando (n=1), badminton (n=1), field hockey (n=1), and basketball (n=1). MR images revealed localized corticalthickness (n=11), linear intramedullary callus showing a low signal on T1 and T2 weighted images (n=9), marrowhyperemia (n=7), and flexor digitorum longus muscle injury showing a high signal on T1-Gd DTPA and T2 weightedimage (n=7). CONCLUSION: Stress fracture of the posterior tibia might be induced by flexor digitorum longusmuscle activity induced by athletic or sporting activities during adoleseence.

MR Imaging Findings of Fatigue Fractures of Lower Extremity in Young Soldiers

PURPOSE: To evaluate the MR imaging findings of fatigue fractures of the lower extremity in young soldiers. MATERIALS AND METHODS: In 22 cases of fatigue fractures of the lower extremity in young soldiers proven byclinical findings and radiological follow up, the MRI findings were retrospectively evalvated. All patients weremale and aged between 19 and 21 years. As seen on MRI, the bone marrow edema, intramedullary low signal intensityband, cortical fracture line, periosteal reaction, surrounding soft tissue edema, and enhancement pattern wereanalyzed and the site of involvement was determined in the axial plane. RESULTS: The locations of fatiguefractures of the lower extremity were the tibia (n=12), fibula (n=8), femur (n=1) and second metatarsus (n=1). Alloccurred in diaphyses: the junction of the proximal and middle (n=10), middle (n=9), proximal (n=2), and distalshaft (n=1). The sites of involvement were the posteromedial (n=6) and medial side (n=6) of the tibia, and theentire portion of the fibula(n=5) in the axial plane. MRI findings were bone marrow edema in 20 cases,intramedullary low signal intensity band in 14 (which were continuous with the cortex or cortical fracture line),cortical fracture line in 13, and periosteal reaction and surrounding soft tissue edema in all. Ongadolinium-enhanced images, enhancement was seen in the bone marrow in 19 cases, in the subperiosteal region in18, and in the surrounding soft tissue in 22. CONCLUSION: In fatigue fractures of the lower extremity in youngsoldiers, the main locations were the tibia and fibula, and characteristic MR imaging findings were intramedullarylow signal intensity bands, which were continuous with the cortex or cortical fracture line and often accompaniedby bone marrow edema, periosteal reaction, and surrounding soft tissue edema.