Intertrochanteric Fracture

An intertrochanteric fracture is an extracapsular proximal femoral fracture involving the region between the greater and lesser trochanters.

Unlike femoral neck fracture, femoral head blood supply is generally preserved and union potential is good.

The principal mechanical question is whether the fracture is stable or unstable.

AO/OTA classification

31A1

Simple pertrochanteric fracture with an intact lateral wall.

Typically relatively stable after reduction.

31A2

Multifragmentary pertrochanteric fracture with posteromedial comminution and an incompetent or compromised lateral wall.

Unstable.

31A3

True intertrochanteric or reverse obliquity pattern involving both medial and lateral cortices.

Subtypes include:

• A3.1 simple oblique
• A3.2 simple transverse
• A3.3 wedge or multifragmentary

These are unstable patterns.

Evans stability classification

Stable

• Posteromedial cortex intact or minimally comminuted
• Cortical contact can be restored
• Fracture can resist compressive loading after reduction

Unstable

• Significant posteromedial comminution
• Lateral wall failure
• Reverse obliquity
• Subtrochanteric extension
• Loss of medial cortical buttress.

Typical patient is an older adult after a low energy fall.

Findings include:

• Groin or proximal thigh pain
• Inability to weight bear
• Shortened externally rotated limb
• Proximal thigh swelling and ecchymosis

High energy fractures occur in younger patients and may be associated with other injuries.

AP pelvis and AP and lateral hip radiographs: usually diagnostic.

Include enough proximal femoral shaft to identify subtrochanteric extension.

MRI is appropriate when an occult hip fracture remains clinically suspected after negative radiographs.

CT is useful when fracture morphology is unusual or when a complex intertrochanteric and subtrochanteric pattern requires further definition.

Most intertrochanteric fractures require operative fixation to permit early mobilisation.

For geriatric hip fracture, aim for surgery on the day of or day after admission once immediately correctable physiological problems are addressed.

Reduction

Reduction quality is one of the strongest determinants of fixation success.

Restore:

• Length
• Neck shaft angle
• Medial cortical continuity
• Appropriate rotation

Avoid varus reduction, which markedly increases implant loading and cut out risk.

Stable fracture

A stable two part pattern can be treated with:

Sliding hip screw with side plate

or

Cephalomedullary nail.

Both provide reliable fixation in appropriately reduced stable fractures.

The sliding hip screw allows controlled collapse and impaction through the fracture.

Unstable fracture

Use a cephalomedullary nail for:

• Reverse obliquity
• 31A3 pattern
• Subtrochanteric extension
• Major posteromedial comminution
• Significant lateral wall incompetence

The intramedullary device provides a shorter lever arm and greater control of unstable patterns.

Cephalic screw positioning

Regardless of implant, fixation in the femoral head must be accurate.

Aim for a central or slightly inferior position on AP imaging and central position on the lateral view.

For lag screw constructs, maintain a tip apex distance below approximately 25 mm to reduce cut out risk.

Avoid:

• Superior head placement
• Excessively shallow screw position
• Varus neck reduction

Postoperative care

After stable fixation, older patients should generally weight bear as tolerated.

Begin mobilisation early.

Provide approximately one month of VTE prophylaxis after fragility proximal femoral fracture when bleeding risk permits.

Evaluate osteoporosis and falls risk.

Major fixation complications include:

• Lag screw cut out
• Varus collapse
• Excessive shortening
• Nonunion
• Implant breakage
• Periprosthetic fracture