Contribution of Bone Scintigraphy in the Diagnosis of a Calcaneus Fatigue Fracture in a Case at the Nuclear Medicine Department of Idrissa Pouye General Hospital (HOGIP) in Dakar

Introduction: Fatigue fractures are secondary to excessive, unusual, repeated mechanical stress, occurring on healthy bone. Bone scintigraphy (BS) with 99mTc-HMDP is an excellent means of diagnosis. We report a case of stress fracture of the calcaneus with scintigraphic diagnosis, in a marathon runner. Patient and Methods: He is a 40-year-old athlete in overtraining with right calcaneal pain on running, intense at first, moderate in the middle and then persistent after exercise. The interrogation found no trauma to the right foot and the x-ray of the foot was without abnormality. The so 3 phases were performed following an injection of 564 MBq of 99mTc-HMDP, with a SPECT gamma camera. Results: Bone scintigraphy found in the early phase, hyper-perfusion and hyper-fixation of the right calcaneal region compared to its left counterpart and in the bone phase persistence of focal hyperfixation opposite the right calcaneus. This scintigraphic aspect of the right calcaneus in a overtrained marathon runner, in a painful context and in front of a normal X-ray, made us evoke a fracture of fatigue. A complementary CT scan performed two days after the BS was without abnormality. Conclusion: Fatigue fractures are micro-fractures generally not noticed on radiography and CT. BS due to its high sensitivity is an excellent or the best tool for the early diagnosis of stress fractures.