Imaging description

Navicular stress fractures are seen on AP radiographs of the foot, coronal CT images, or coronal MR images as a linear or curvilinear fracture line extending longitudinally in the sagittal plane (Figure 74.1). Stress reaction of the navicular can be seen as bone marrow-like edema within the navicular on MR images. When the fracture line is curvilinear it will typically curve laterally. Stress fractures of the navicular can also be complete or incomplete. When incomplete they will be proximal in location and usually involve the proximal articular surface of the navicular bone.

Importance

Navicular stress fractures typically occur in athletes and can be difficult to diagnose on clinical exam. A high degree of suspicion must be present. Given the difficulty in diagnosing this injury clinically, the average time from onset of symptoms to diagnosis is between four to seven months. Navicular stress fractures respond well when they are treated early; however, the delay in diagnosis that usually occurs can result in suboptimal treatment. Unfortunately, misdiagnosis and delayed diagnosis resulting in inadequate treatment of these lesions can have disastrous consequences for the athlete.