Femoral Neck Stress Fracture xray

A 24-year-old male presents with progressively worsening left groin pain for six weeks after he began training for a marathon. He states he had x-rays done by his PCP that were negative four weeks ago and was diagnosed with a groin strain. X-rays were obtained and featured to the right.

What is your diagnosis? What is the typical mechanism? What is your management in the Emergency Department? What is your disposition?

FNSF

Figure 1: Case courtesy of Dr. Hein Els, Radiopaedia.org.

Femoral neck stress fracture (FNSF)

  • Pearl: FNSF diagnosis is difficult because the physical exam is non-specific. Patients present with an antalgic gait, pain with end range of motion at the hip, pain with combined flexion, abduction and external rotation, and pain with hip log roll [2].
  • Pearl: X-rays for FNSF usually are not positive early in the course and if missed can lead to complications such as complete fracture, displacement, non-union, and avascular necrosis. Keep a high clinical suspicion in a running athlete [3,4].
  • Femoral neck stress fractures are usually a result of repetitive abductor muscle contraction [1].
  • Onset is often insidious. Pain is worse with weight-bearing and activity and improves with cessation of activity. The injury often occurs secondary to a recent change in activity intensity or volume [1,2].
  • Femoral neck stress fractures are uncommon injuries, but are prevalent among long-distance runners and military recruits.
  • Obtain AP and oblique hip radiographs to start
  • Pearl: There are two sites where the stress fracture can occur.
    • Compression side (inferior femoral neck) which is seen in this case.
      • The patient should be made non-weight bearing with crutches.
    • Tension side (superior femoral neck). These fractures are less common but require surgical fixation [1,2].
      • Orthopedics should be consulted in the emergency department to determine whether the patient should go for urgent internal fixation [1,2,3].
  • Pearl: If the patient is non-weight bearing, consider a rapid MRI of the hip (see Figure 2). These scans with the appropriate technician can be performed in 5-10 minutes [5].

Figure 2: MRI of the left hip demonstrating a linear hypointense signal at the base of the femoral neck. Case courtesy of Dr. Hein Els, Radiopaedia.org

  • Compression side FNSF: Discharge with follow-up with sports medicine or orthopedics in 1-3 days for further management.
  • Tension side FNSF: Will be determined on a case-by-case basis – discuss with orthopedics if inpatient management is required.

References:

  1. Brukner P, Khan K. Brukner & Khans Clinical Sports Medicine. North Ryde, N.S.W.: McGraw-Hill Education (Australia); 2017
  2. Harrast MA, Finnoff JT. Sports Medicine: Study Guide and Review for Boards. New York, NY: Demos Medical Publishing; 2017
  3. Biz, C., Berizzi, A., Crimi, A., et al. Management and Treatment of Femoral Neck Stress Fractures in Recreational Runners: A Report of Four Cases and Review of the Literature. Acta Biomedica. 2017; 88(4): 96-106. PMID: 29083360
  4. Clough, T. Femoral Neck Stress Fracture: The Importance of Clinical Suspicion and Early Review. 2002; 36(4): 308-309. PMID: 12145125
  5. Lauren May MA, Chen DC, Liem Bui-Mansfield CT, Usa M, Seth O LD. Rapid Magnetic Resonance Imaging Evaluation of Femoral Neck Stress Fractures in a U.S. Active Duty Military Population. Mil Med. 1619;182. PMID: 28051983
Aimee Monahan, DO

Aimee Monahan, DO

Fellow
Department of Family Medicine
University of Arizona/Banner Health
Aimee Monahan, DO

Latest posts by Aimee Monahan, DO (see all)

Brendan Parker, MD

Brendan Parker, MD

Fellow
Department of Emergency Medicine
University of Arizona
Brendan Parker, MD

Latest posts by Brendan Parker, MD (see all)

William Denq, MD CAQ-SM

William Denq, MD CAQ-SM

Assistant Professor
Department of Emergency Medicine
University of Arizona
William Denq, MD CAQ-SM

@willdenq

Clinical Assistant Professor Emergency Medicine and Sports Medicine University of Arizona George Washington University '18 University of Pittsburgh '14 and '10
William Denq, MD CAQ-SM

Latest posts by William Denq, MD CAQ-SM (see all)