Background: Femoral neck stress fracture (FNSF) accounts for 3% of all sports-related stress fractures. The most common cause is marathon running. The main types of FNSF are compression-sided, tension-sided, and displaced fracture. The most common symptom is groin pain. Plain radiograph is the first-line investigation, and the magnetic resonance imaging (MRI) is the second-line investigation. The location and displacement of the fracture guide the management. Early detection and diagnosis decrease the rate of fracture displacement and osteonecrosis of the femoral head.

Objective: To report two cases of FNSF that developed in two Thai marathon runners, and to review what is currently known about FNSF in this specific sports-related setting.

Materials and Methods: Two cases of FNSF are described, and a review of the literature relative to FNSFs in long-distance runners describes the role of imaging, management, and return to running.

Results: FNSFs are a rare injury, and marathon runners  presenting with exercise-related groin pain should be evaluated. Management is based on fracture location and whether or not the fracture is displaced. The first case profiles a patient with delayed FNSF diagnosis. Fracture displacement was found two weeks after symptom onset, and total hip arthroplasty was performed. The second case describes a patient with early FNSF diagnosis that was treated conservatively with good outcome.

Conclusion: Although FNSF is a rare injury, it should be considered in marathon runners who present with exercise-related groin pain. Delayed diagnosis can adversely affect quality of life. Early detection and management of FNSF shows excellent results in terms of return-to-sport rates.

Keywords: Femoral neck stress fractures, sport-related injuries, stress fracture, marathon runners, long-distance running