ESIN (retrograde)

The ESIN method involves closed reduction and internal fixation with elastic nails.

It is difficult to treat shaft fractures of the middle and proximal third with antegrade nail insertion as the nail entry sites are close to the fracture and the configuration of the nails does not produce sufficient stability.

Using a retrograde nail construct will provide sufficient stability in these fractures.

• 2.5–4.0 mm elastic nails
• Awl or drill
• Inserter
• Hammer
• End caps and insertion device
• Impactor
• Extraction plier
• Nail cutter

The end cutter is useful to avoid sharp ends and soft-tissue irritation.

The F-tool can be helpful to align the femur.

For optimal stability, the nail diameter should be between 33% and 40% of the narrowest part (isthmus) of the medullary canal.

A larger size of the nail may be required for increased stability.

Both nails need to be of the same diameter.

Place the patient in a supine position on a radiolucent fracture table with or without traction.

When positioning the patient check the rotational alignment of the uninjured femur.

Expose the bone at both entry points.

Place the awl or drill directly onto the bone and perforate the near cortex, under direct vision, perpendicular to the bone.

Do not hammer the awl to avoid perforation of the far cortex.

When the medullary canal is entered, lower the awl or drill 45° to the shaft axis. Advance it with oscillating movements to produce an oblique canal.

In multifragmentary fractures the contouring should be gentle C-shaped over the whole length of the bone.

Insert the first nail through the lateral entry point into the intramedullary canal and advance it towards the fracture site with an oscillating maneuver.

Insert the second nail into the medial entry point in an identical manner.

Advance the first nail past the fracture zone and into the distal fragment with an oscillating maneuver.

Advance the second nail in the same way.

Use the nails as joysticks to reduce the main fragments.

If necessary, use an F-tool to align both fragments.

If this is unsuccessful use a bone hook or Steinmann pin through a small incision.

Open reduction (through a limited lateral approach) may be necessary if closed reduction cannot be achieved.

Advance the first nail past the fracture site through the floating segment and into the distal fragment with gentle hammer blows.

This avoids rotation and splitting of the middle segment.

Advance the second nail in an identical manner.

A wedge fragment does not need to be reduced anatomically.

If it the fracture is axially unstable, end caps are recommended.

Confirm rotational alignment of the femur clinically and radiographically before fixing the second fragment. This can be done by:

• Fluoroscopy of the fracture site (matching shaft diameters)
• Comparing internal and external rotation to the contralateral side (consider preparing and draping the uninjured side as well)
• Fluoroscopy of proximal femur (lesser trochanter profile)

For more detail see the additional material on assessment of rotation.

Advance the nail started on the medial side and impact it at least to the level of the lesser trochanter.

Impact the nail started on the lateral side towards the greater trochanter. Optimally the nail tips are at the same level.

Align the nail tips so that they diverge.

For a fracture in the proximal third advance the medial nail into the femoral neck and the lateral nail into the greater trochanter.

Cut the nails with the dedicated nail cutter.

If this is not available, withdraw the nails far enough to apply the nail cutter.

Reinsert the nails so at least 1 cm of the nail remains outside the bone.

The ESIN impactor can be used to ensure the optimal length of the nail outside the bone to apply an end cap.

End caps can be used to increase axial stability.

They will also protect soft tissues.

Insert the end cap over the cut end of the nail and screw it into the metaphysis.

Confirm that the end cap is covering the nail and fixed to the bone with image intensification.

Check the range of internal and external rotation of the leg and compare with the contralateral limb.

Obtain final AP and lateral fluoroscopic views.

The patient should get out of bed and begin ambulation with crutches on the first postoperative day.

In most cases the postoperative protocol will be protected weight bearing for the first 4 weeks.

Routine pain medication is prescribed for 3–5 days postoperatively.

The patient should be examined frequently, to exclude distal neurovascular compromise.

Compartment syndrome, although rare, should be considered in the presence of severe swelling, increasing pain, and changes to neurovascular signs.

Discharge from hospital follows local practice and is usually possible after 1–3 days.

The patient should ambulate with crutches and begin knee range-of-motion exercises.

Clinical and radiological follow-up is usually undertaken every 2–8 weeks until radiographic healing and restoration of function.

Clinical assessment of leg length and alignment is recommended at one-year.

Clinical assessment of leg length uses a tape measure from the ASIS to the medial malleolus.

If there is any concern about leg length discrepancy or malalignment, long-leg x-rays are recommended.

Leg length is measured from the femoral head to the ankle joint.

If the patient develops symptoms related to the implant, it can be removed once the fracture is completely healed, usually 6–12 months following injury.