A 25-year-old male footballer with a past history of lumbar disc pathology presents with a three-month history of a deep constant left thigh ache that is worse at night and responds to painkillers including acetaminophen and ibuprofen. This followed a heavy preseason load of running but persisted despite rest.
There was no significant abnormality found following clinical examination of his lumbar spine, hip and knee.
An MRI scan showed marrow oedema within the left mid-femoral shaft. There was mild thickening of the lateral cortex with an amorphous intermediate signal abnormality and periostitis. This was initially interpreted as a stress fracture. When the patient failed to improve with rest, the MRI was repeated which showed worsening of the endosteal marrow oedema, periostitis and a clear lucent defect within the lateral cortex of the femur. A subsequent CT scan illustrated a nidus with discrete calcification within a lucent defect and linear bands leading away from the centre. There were layers of cortical thickening with bone remodelling and a periosteal reaction.
Based on the radiological finding an osteoid osteoma was diagnosed. These are most common in young males and should be considered as a differential diagnosis for a stress fracture, especially when the pain worsens at night and is alleviated with nonsteroidal anti-inflammatories. In retrospect the location of the lesion was a clue to this not being a bone stress injury. The majority of femoral stress fractures involve the medial femur (not lateral) and relate to proximal muscle attachments.
CT imaging is generally considered to be superior to MRI for demonstrating the calcific nidus. MRI can be very useful for localising the lesion and demonstrating bony activity to differentiate it from vascular channels or bone cysts.
FIFA does not bear any responsibility for the accuracy and completeness of any information provided in the “Radiology Review” features and cannot be held liable with regard to the information provided or any acts or omissions occurring on the basis of this information.