Findings: The initial views of the right foot from April 1997 demonstrate no fractures (see lateral view of the right ankle from April 1997). A subsequent bone scan was performed. The delayed lateral views of the feet demonstrate two linear areas of increased radiopharmaceutical uptake within the right calcaneus. The left calcaneus demonstrates a linear area of increased radiopharmaceutical uptake at its superior margin. Follow-up radiograph of the right foot in the lateral projection demonstrates two linear areas of increased density within the right calcaneus corresponding to the areas of increased radiopharamceutical uptake. The lateral view of the left foot demonstrates a linear area of increased bone density which also corresponds to the abnormality on the patient’s bone scan of the left foot.

Diagnosis: Two stress fractures of the right calcaneus and a single stress fracture on the left.

Discussion: This patient was initially referred for edema of the right ankle and foot as well as right heel pain. The symptoms had been present for approximately one month without a history of trauma. The patient’s initial radiographs of the right foot were normal. The patient was subsequently treated with anti-inflammatory agents as well as a right lower extremity ultrasound. These examinations were negative. Since the patient’s symptoms were persistent, three-phase bone scintigraphy was performed. These images were positive for calcaneal stress fractures. Follow-up radiographs were also positive.

This clinical history is typical for the presence of a stress fracture in an elderly patient. In a review of three-phase bone scintigraphy in sports medicine 69.3% of initial radiographs were normal. In this series, 77.7% of the three-phase bone images were abnormal in at least one phase. 22.3% of the examinations were normal in patients who had final diagnoses of soft tissue pathology. Stress fractures typically occur in normal bones subjected to increased stress such as, in military recruits or specific sports such as running, gymnastics, blade and roller skating. In elderly patients, stress fractures are also referred to as insufficieny fractures, since the fracture occurs in normal bones subjected to a normal amount of stress. Insufficiency fractures occur in a variety of conditions; a common underlying condition is osteoporosis of aging. Other causes include rheumatoid arthritis; osteomalacia, osteogenesis imperfecta, hyperparathyroidism, scurvy, Paget’s disease, and fibrous dysplasia.

References:
Frupany HD, Holder LE, Espanola BA, Ngn SI. Three-phase Radionuclide
Bone Imaging in Sports Medicine. Radiology 1985;156:187-196.

Reeder MT, Dick BH, Atkins JK. Stress Fractures. Current Concepts of
Diagnosis and Treatment. Sports Medicine 1996;22(3):198-212.

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