An Avulsion Fracture of the Lesser Trochanter of the Femur with Prodromal Symptoms in an adult: A Case Report and Review of Literature

INTRODUCTION: An avulsion fracture of the lesser trochanter of the femur in adults is rare and should be differentiated from neoplastic lesions. We present a rare case of avulsion fracture of the lesser trochanter of the femur with prodromal symptoms in an adult. CASE REPORT: A right-handed 40-year-old man with gradual-onset left hip joint pain resulting from baseball pitching consulted a neighborhood doctor. X-ray images did not show any obvious anomalies; however, the pain persisted. Two months after the onset of pain, he stumbled when getting into a car, and the pain worsened. He was then brought into our hospital’s emergency unit, and an avulsion fracture of the lesser trochanter of the left femur was detected. Due to mild displacement (<20 mm) and no neoplastic lesions by gadolinium-enhanced magnetic resonance imaging and the technetium scintigraphy, he was managed conservatively. During the final follow-up, 1 year after the onset of symptoms, non-union of the lesser trochanteric fracture was noticed. However, there were no pain and no limited range of motion at the hip joint; therefore, he had no problems with daily activities and sports. CONCLUSION: The avulsion fracture of the lesser trochanter of the femur in our patient may have been caused by repeated flexion, adduction, and internal rotation of the hip joint during baseball pitching. Although bone union was not achieved, his condition was managed successfully using conservative treatment. Our experience offers a few key learning points to manage such rare fracture occurrences in adults and suggests that conservative treatment is often sufficient for mild displacement (<20 mm) of the fracture.