Femoral Neck Fractures

What are the four disadvantages to dynamic hip screws

1) prominent implants 2) affects biomechanics of hip joint 3) lower physical function on SF-36 4) decreased quality of life

What are the guidelines for acceptable hip reduction?

AP - valgus or anatomic alignment Lateral view maintain anteversion while avoiding posterior translation

Where is the capsule of the femur attached?

Anteriorly on Intertroch line, posteriorly 1-1.5 cm proximal to intertroch line

When is ORIF indicated in Femoral neck fractures?

Displaced fracture in young or physiologically young patients (usually if <65)

When must patients be taken to surgery for hip fracture?

Less than 4 days, as soon as medically optimal

What is the major blood supply to the femoral head? What are 4 minor contributors?

Medial femoral circumflex is major supply Some from anterior and inferior head from lateral femoral circumflex Some from inferior gluteal artery Small amount from ligamentum teres

When is THA indicated?

Older active patients Have preexisting hip osteoarthritis (more predictable and better functional outcome than hemi) <85 years Garden III or IV

Why does a valgus osteotomy work in nonunion?

Turns the vertical fx line into horizontal fx line and decreases shear forces across fracture line

What are the four treatment options for nonunion in femoral neck fractures?

Valgus Intertroch osteotomy Free vascularized fibula graft - must be young and have viable head Arhtroplasty - older patients and nonviable heead revision ORIF

What most closely correlates with failure of fixation after reduction and cannulation screw fixation?

Varus malreduction

Why is it important to be in calcar during screw fixation?

stronger fixation and higher load to failure

Co managing these trauma patients results in?

1) Decreased mortality 2) Decreased post-op complications 3) Decreased time to surgery 4) improved post op mobility at 4 months

What is normal femoral anteversion?

10 +/- 7 degrees

What is the normal neck shaft-angle?

130 +/- 7 degrees

What is the prognosis of femoral neck fractures? What predicts post op survival?

25-30 percent at one year Pre injury mobility most significant CKD - 2 year mortality is 45%

How many of impacted neck fractures develop ON?

5-15% develops ON

What X-Rays ordered for femoral neck fractures?

AP Pelvis AP Hip and cross table lateral with traction internal rotation to best define fracturre AP Femur

What is the epidemiology of the femoral neck fractures?

Aging population Women > men Whites > blacks Most expensive fracture in the US

Three goals of treatment for hip neck fractures?

Allow rapid mobilization, restore hip function, decrease discomfort

What are indications for a sliding hip screw

Basicervical Vertical fracture pattern in young patient Can place cannulated screw above sliding hip screw to prevent rotation

What is the main osteology about the femoral neck responsible for its stability? Describe its orientation?

Calcar femorale - vertically oriented plate from PM portion of shaft radiating to greater troch

Are MRI, bone scan, and duplex useful in femoral neck fractures?

Can assess occult fracture but not good for reliably assessing viability of femoral head after fracture Duplex rules DVT out after hip fracture

When are hemiarthroplasties indicated in femoral neck fractures

Debilitated old patients with metabolic bone disease

Two subcategories of low energy hip fractures?

Direct - fall onto greater trochanter OR forced external rotation of LE impinges osteoportoic neck onto posterior acebaulum (get posterior comminution) Indirect - Muscles overwhelm strength of neck

Following hip fracture what is essential? Why?

Early bed to chair mobilization! Decreases risks and complications of poor pulm toilet, atelectasis, venous stasis, and pressure sores.

If a femoral neck fracture is found, what else must be evaluated? Which injury if found should be addressed first?

Femoral shaft fracture - 6-9% of them associated with neck fractures Must fix neck first becuase anatomic reduction necessary to avoid AVN and nonunion

Describe the trabecular anatomy of the femoral head

Forms parallel to direction of compressive forces Bony trabeculae laid down along the lines of internal stress Vertically oriented trabeculae result from weight bearing forces across femoral head Set of horizontally oriented trabeculae from abductor forces

Compression sided stress fractures are seen where? Are they at risk?

Haze of callus at inferior neck Minimal risk for displacement without additional trauma - Tx with protective crutch ambulation until asx and only surgery if painful or refractory fractures.

What did 2 year follow up show in patients with >70 years and displaced femoral neck fractures? What about 2-10 year followup?

High prior to 2 years, levels off after 1) 46% with fixation techniques 2) 8% with arthroplasty 2-10 years had a 2-4% failure rate (but fixation still higher failure rates than THA)

Describe the technique for fracture reduction of femoral necks

Hip flexion with traction and ER to disengage fragments Then slow extension and internal rotation

What three ligaments attach in the area of the femoral neck

Iliofemoral: Y ligament of Bigelow (anterior) Pubofemoral: anterior Ischiofemoral: posterior

Advantages vs disadvantages of THA in femoral neck fracture

Improved functional hip scores and lower reop rates compared to hemiarthroplasty even though higher rates of dislocation with THA (~10%) and is 5 x higher than hemis

How many "impacted" fractures displace?

In 40% of impacted or nondisplaced fractures will displace without internal fixation

What increases the risk of ON in femoral neck fractures? What is the treatment of ON?

Increases with initial displacement and nonanatomical reduction Tx: Young patient - 50% involvement then treat with FVFG vs THA Older patients - prosthesis

How does DHS compare to cannulated screws?

Lower reop rates for SHS in: 1) displaced femoral neck fractures 2) basicervical neck fracture 3) Current smokers

What are indications for cannulated screw fixation in hip fracture?

Nondisplaced transcervical fx Garden 1 or II in elderly displaced transcervical in young patient (this is an emergency to reduce loss of vascular insult so it must be anatomic)

Is open vs closed reduction superior in femoral neck fractures?

None is superior but there are worse outcomes with displacement > 5mm (higher rates of osteonecrosis and nonunions) Should not attempt multiple closed reductions because higher risk of ON

What is second highest complication of femoral neck fracture?

Nonunion in 5-30% patients increased with displaced fracture (no correlation with age, gender)

78 yo Patient with valgus impacted hip fracture treated with CRIF done 11 months ago now complains of groin and butt pain, pain with extension of hip and pain with weight bearing. What is dx? Tx?

Nonunion, treat with arhtroplasty of proximal femoral osteotomy if young

Nonoperative treatment is considered when for hip fractures?

Only if extreme medical risk OR demented nonambulator without pain

Describe the three screw fixation technique?

Only if noncommunited 3 inverted screw triangle placed: 1) Inferior screw along calcar 2) Posterior/Superior screw 3) Anterior/Superior screw Starting point must be at or above level of lesser trochanter to avoid fracture and obtain as much spread as possible.

78 yo Patient with valgus impacted hip fracture treated with CRIF done 11 months ago now thigh and butt pain. What is dx? Tx?

Osteonecrosis Early without xray changes - weight bearing or possible core decompression Late with xray changes - Tx with arthroplasty whereas younger patients treated with osteotomy, arthrodesis, or arthroplasty

What is highest complication of femoral neck fracture?

Osteonecrosis (10-45%)

What are contraindications to three screw fixation in impacted neck fractures? What is done instead?

Pathologic fractures, severe OA/RA, Paget disease, or other metabolic conditions. Instead do prosthetic replacement.

Describe approaches to hemiarthroplasty in femoral neck fractures

Posterior - increased risk dislocation Anterolateral - increased abductor weakness Cemented > uncemented

What has more effect on healing, reduction method/quality or timing?

Reduction quality

Tension sided stress fractures are seen where? Are they significant?

Seen at superior lateral neck on an internally rotated AP view Significant risk for displacement so must do in situ fixation

Why is it important to not perforate cortex multiple times?

Should not do it with guid pin or screw to avoid development of lateral stress riser

The forces across the hip joint are changed how much if 1) straight leg 2) One legged stance 3) Two legged stance

Straight leg: 1.5 x BW One - legged : 2.5 x BW Two legged - 0.5 x BW

Symptoms and physical exam of hip fractures?

Sx - Impacted and stress fractures (pain in groin or referred along medial knee and thigh) if impacted or minimal displacement. Displaced fractures have entire hip pain PE- Impacted and stress - no obvious deformity but may have minor discomfort with active or passive hip rom, pain with percurssion over greater trochanter Displaced- external rotation and abduction with shortening

Why are femoral neck fractures so important to reduce correctly?

The neck is intracapsularand bathed in synovial fluid and lacks periosteal layer so callus formation limited