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Femoral neck fractures are intra-capsular fractures of the proximal femur, at the neck of the femur between the trochanteric line and head of the femur. They are associated with avascular necrosis of the head of the femur, impaired healing and have a high risk of morbidity and mortality. Stress fractures uncommon, but are possible, especially in athletes who are starting a new activity.
Treatment depends on displacement of the fracture, bone quality and location of the fracture.
Bimodal distribution. Affects women more than men. it has a high mortality, with a 25 – 30% 1 -year risk.
Garden classification: based on AP X-ray to determine management based on stability of the fracture. Does not consider lateral or sagittal plane alignment. Posterior roll-off and/or angulation of the femoral head leads to increased reoperation rates
| Classification | Description | Treatment |
|---|---|---|
| Type I | Incomplete fracture, valgus impacted | Cannulated screw fixation |
| Type II | Complete fracture , non-displaced | Cannulated screw fixation |
| Type III | Complete fracture, partially displaced (< 50%) | ORIF, Hemiarthroplasty vs total hip arthroplasty |
| Type IV | Complete fracture, fully displaced | ORIF, Hemiarthroplasty vs total hip arthroplasty |
Simplified Gardens Classifiaction
| Classification | Gardens | Treatment |
|---|---|---|
| Non-displaced | Garden type I and type II | Cannulated screw fixation |
| Displaced | Garden type III and IV | Hemiarthroplasty vs total hip arthroplasty |
Pauwels classification for femoral neck fracture (looks at orientation of the fracture line to determine stability)
| Classification | Description |
|---|---|
| Type I (stable) | < 30 degrees from horizontal |
| Type II (less stable) | 30 – 50 degrees from horizontal |
| Type III (unstable) | > 50 degrees from horizontal. Most unstable with the highest risk of avascular necrosis |
- Anatomy
- The femoral neck is intracapsular with limited blood supply. It lacks a periosteal layer and is surrounded by synovial fluid. It’s limited blod supply impairs hearing
- Parts include subcapital vs transvervical vs basicervical
- Neck to shaft angle is about 130 degrees and an angle of anteversion of about 10 degrees
- Major blood supply is the lateral epiphyseal branch of the medial femoral circumflex artery. Other branches arise from the lateral femoral circumflex, inferior gluteal artery and insignificant supply from the arter yo fht eligamentum teres. A displaced fracture disrupts blood supply to the femoral he
- The calcar femorale is located in the posteromedial aspect and made of a dense plate of bone. It transfers stress from the trabecular bone of the head to the cortical boen of the shaft.
- Mechanism
- High energy mechanism (young patients)
- Motorvehicle accident
- Fall from height
- Low energy mechanism (elderly or osteoporotic)
- Fall from standing height
- High energy mechanism (young patients)
- Associated injuries
- Signs and symptoms
- Physical examination
- Pain with log roll or straight leg raise
- No obvious deformity (non-displaced)
- External rotation and shortening (displaced – natural position of the femur when it is not held by ligaments)
- Tenderness on percussion of th egreater trochanter
- Investigations
- X**-ray:** AP pelvis, AP Hip, cross-table lateral hip, full-length femur and traction-internal rotation AP hip
- AP view to determine lateral displacement
- Cross-table lateral view to ****determine AP displacement
- CT scan: to determine displacement and degree of comminution. Also for surgical planning
- MRI: Gold standard for occult fracture
- Bone scan: to rule out occult fracture
- Dopple ultrasound of both lower limbs: to rule out DVT in patients with delayed presentation after hip fracture
- X**-ray:** AP pelvis, AP Hip, cross-table lateral hip, full-length femur and traction-internal rotation AP hip
- Conservative treatment
- Observation: in non-ambulatory patients with minimal pain and high surgical risk
- Operative treatment
- Closed reduction with Percutaneous fixation (inverted triangle of partially threaded cannulated screws): for non-displaced fractures in physiologically elderly and displaced transcervical fractures in young patients. Open reduction may be performed for anatomic reduction.
- Open reduciton internal fixation (ORIF) with sliding (dynamic) hip screw: for displaced fractures in young or physiologically young patients with basicervical and vertical fractures.
- Arthroplasty
- Prognostic factors
- Pre-injury ambulatory status (most important predictor for post-op survival)
- Age
- Cognitive function
- Comorbidities
- Time of surgery (mortality decreases if surgery is performed within 48 hours)
- Complications of femoral neck fracture
- Avascular necrosis: risk is increased with a displaced fracture and in non-anatomic reduction
- Deep venous thrombosis
- Post-operative non-union: especially in ORIF
- Malunion: varus malreduction. Treated with intertrochanteric osteotomy or arhtoplasty
- Dislocation of prosthesis (10%): Risk is higher with total hip arthroplasty than hemiarthroplasty