Fig. 9
From: Stress fracture of the pelvis and lower limbs including atypical femoral fractures—a review
A male patient in his early 60s underwent surgical resection and postsurgical radiotherapy of the right groin and proximal femur for a soft tissue sarcoma. Five months after the radiotherapy the patient experienced right groin pain, and local recurrence was suspected. MRI showed a severe stress fracture of the right acetabulum [coronal T1w (a) and coronal STIR (b) images; see arrows]. Eleven months after the radiotherapy the patient developed a spontaneous right femoral neck fracture after prodromal pain. Coronal MRI (c T1w, d STIR) shows the absence of an underlying malignancy, an impacted femoral neck fracture (arrowhead) and bone marrow with high fat content. The stress fracture of the acetabular roof has largely healed (arrows). There is persistence of marked soft tissue oedema after radiotherapy. CT imaging (e, coronal reformat) also demonstrates the femoral neck fracture (arrowhead) and shows mild sclerosis of the bone marrow in the femoral head and neck, and no obvious osteopenia. The acetabular stress fracture can be appreciated as an area of sclerosis (arrows). Radiotherapy impairs the bone repair capability and predisposes the patient to stress fractures, often in the first year after radiotherapy