Femoral Neck Stress Fractures

Introduction

Fracture of the femoral neck secondary to repetitive loading of bone
- two types
  - compression side (inferior-medial neck)
  - tension side (superior-lateral neck)
Epidemiology
- common in runners
Mechanism
- repetitive loading of femoral neck
Pathophysiology
- repetitive loading causes microscopic fractures in the femoral neck
  - crack "initiation"
- continued repetitive loading does not allow for healing response and stress fracture occurs
  - crack "propagation"
Associated conditions
- "female athlete triad"
  - amenorrhea, eating disorder, and osteoporosis
  - must be considered in any female athlete with stress fracture
Prognosis
- dependent upon patient compliance

Anatomy

Muscle insertions around femoral neck
- iliopsoas
- quadratus femoris
- gluteus medius
- piriformis
Blood supply to femoral neck
- provided by two branches of the femoral artery including
  - medial femoral circumflex artery
  - lateral femoral circumflex artery
Biomechanics of femoral neck
- compression side
  - inferior medial neck with weight bearing
- tension side
  - superior lateral neck with weight bearing

Presentation

History
- history of overuse or increase in normal training regimen
Symptoms
- insidious onset of pain
  - improves with cessation of activity
  - high impact activities increase pain
- anterior thigh or groin pain with weight bearing
Physical exam
- usually benign exam
- may have tenderness directly over femoral neck region with deep palpation

Imaging

Radiographs
- recommended views
  - AP pelvis, AP and lateral of hip
- findings
  - usually negative
  - later findings include linear lucency and cortical changes
MRI
- sensitive and specific for diagnosis
- detects early changes
- modality of choice for stress fractures when radiographs are normal
Bone scan
- has good sensitivity but very poor specificity (therefore MRI is better)

Treatment

Nonoperative
- non-weight bearing and activity restriction
  - indications
    - compression side stress fractures (inferior-medial neck)
Operative
- ORIF with percutaneous screw fixation
  - indications
    - tension side stress fractures (superior-lateral neck)

Complications

Fracture progression
- occurs if fracture is unrecognized and the athlete continues to train

TAG

(OBQ11.184) A 24-year-old female marathon runner experiences gradual onset of right groin pain. Initially it was only painful during running, but now it is painful with walking. She has no mechanical symptoms and denies back or lower leg symptoms. On exam, she has pain when attempting a straight leg raise and with passive internal rotation of the hip. Pelvis and hip radiographs demonstrate normal acetabular version and normal femoral head-neck offset. What is the next most appropriate step in her care? Topic

Review Topic

1. Intra-articular hip corticosteroid injection
2. Tapered oral corticosteroid dosing regimen for one week
3. EMG and nerve conduction studies
4. MR imaging of the hip
5. CT abdomen and pelvis to evaluate for sports hernia

PREFERRED RESPONSE ▶

DISCUSSION: Gradual onset, progressive groin pain in a marathon runner is concerning for a femoral neck stress fracture, which warrants further imaging such as an MRI or bone scan. Normal radiographs are common and do not preclude the presence of a stress fracture.

Treatment recommendations are based on the location and severity of the fracture. Compression-sided fractures are usually treated non-operatively, with protected weight-bearing until pain-free, and cessation of running until healed. Tension-sided fractures and fractures that involve more than 50% of the femoral neck are generally treated operatively with percutaneous screw placement. A careful evaluation of the training regimen, dietary history, and menstrual history should also be performed.

Incorrect Answers:
1. & 2. Corticosteroids are not used for treatment of stress fractures. An injection may be useful in the diagnosis and treatment of intra-articular pathology, such as a hip labral tear.
3. Hip and back pain can overlap and an EMG/NCV study can be used to evaluate for lumbar radiculopathy.
5. The clinical scenario is not typical of sports hernia and the use of imaging modalities to diagnose sports hernia remains controversial.

REFERENCES:

1. Shah A, Busconi B. Hip and pelvis. In: DeLee JC, Drez D, Miller MD, eds. Orthopaedic Sports Medicine. 3rd ed. Philadelphia, PA: Saunders-Elsevier; 2010:1451-1477.

2. Sekiya JK, Gibbs AE. Groin and pelvis injuries. In: Kibler WB, ed. Orthopaedic Knowledge Update: Sports Medicine 4. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2009:83-90.

Question Authors:

Patrick McCulloch MD, Patrick McCulloch MD, John Badylak MD,

Please Rate Educational Value!

4.0

Average 4.0 of 5 Ratings

TAG

(OBQ04.272) A 20-year-old male marathoner has had left sided groin pain for the past 4 weeks. He has continued to maintain his routine running regimen despite the discomfort. Radiograph, bone scan, and MR images are shown in Figures A-D. What is the most appropriate next step in management? Topic

Review Topic

FIGURES: A

1. Referral to orthopaedic oncologist
2. Valgus intertrochanteric osteotomy
3. Hip arthroscopic evaluation and labral repair
4. Percutaneous screw fixation
5. Irrigation and debridement with course of intravenous antibiotics

PREFERRED RESPONSE ▶

DISCUSSION: The patient's history and imaging are consistent with a femoral neck stress fracture. While most compression-sided fractures may be treated non-operatively with protected weightbearing, percutaneous screw fixation is indicated for tension-sided fractures and compression-sided fractures that extend greater than 50% of the way across the neck, as in this case.

The fracture is not evident on the pelvis radiograph but is visualized on the bone scan, T1, and T2 MR images. Bone density is not an important consideration in the decision to surgically treat a stress fracture of the hip, however whether the stress fracture is compression versus tension-sided is important. A visible fracture line on radiographs obviates the need for a MRI and increases the likelihood of displacement being present. Displaced femoral-neck fatigue fractures are urgent surgical situations.

The review article by Shin et al suggest that tensile forces at a stress-induced fracture often lead to poor healing and require aggressive operative treatment to avoid osteonecrosis, malunion, and coxarthrosis. The authors also suggest that compression-sided fracture that involves >50% of the neck (as demonstrated in this case) should have strong consideration for operative fixation or alternatively be placed on strict nonweightbearing with weekly radiographs to evaluate for displacement.

REFERENCES:

1. Shin AY, Gillingham BL. Fatigue Fractures of the Femoral Neck in Athletes. J Am Acad Orthop Surg. 1997 Nov;5(6):293-302. PMID:10795065 (Link to Abstract)

Question Authors:

Michael Hughes MD, John Badylak MD, Dave Marcu MD,

Please Rate Educational Value!

4.0

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Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions, Personal Observations, and Biomechanic Studies)

Shin AY, Gillingham BL. Fatigue Fractures of the Femoral Neck in Athletes. J Am Acad Orthop Surg. 1997 Nov;5(6):293-302. PMID:10795065 (Link to Abstract)

Textbooks

Review of Orthopaedics, 6th Edition, Mark D. Miller MD, Stephen R. Thompson MBBS MEd FRCSC, Jennifer Hart MPAS PA-C ATC, an imprint of Elsevier, Philadelphia, Copyright 2012
AAOS Comprehensive Orthopaedic Review, Jay R. Leiberman. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2009
Orthopaedic Knowledge Update 10, John M Flyn. Published by American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2011
Hoppenfeld SP. Surgical Exposures in Orthopaedics: The Anatomic Approach. Lipponcott, Williams, and Wilkins, Philadelphia, PA, Copyright 2009
Orthopaedic In-training Examination (OITE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Self-Assessment Examination (SAE) Questions 2004-2012, American Academy of Orthopaedic Surgeons, Rosemont IL. Copyright 2004-2012
Sekiya JK, Gibbs AE. Groin and pelvis injuries. In: Kibler WB, ed. Orthopaedic Knowledge Update: Sports Medicine 4. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2009:83-90.
Shah A, Busconi B. Hip and pelvis. In: DeLee JC, Drez D, Miller MD, eds. Orthopaedic Sports Medicine. 3rd ed. Philadelphia, PA: Saunders-Elsevier; 2010:1451-1477.

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