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Authors of section


Arnold Besselaar, Daniel Green, Andrew Howard

Executive Editor

James Hunter

General Editor

Fergal Monsell

Open all credits

ESIN (retrograde)

1. General considerations

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.

Final construct

2. Instruments and implants

Instrument set for ESIN

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

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

End cutter

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


Nail diameter

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

Both nails need to be of the same diameter.

Pearl: To estimate the optimal nail diameter place the selected nail on the leg parallel to the bone and check with an image intensifier (as shown in the illustration).
For later precontouring mark the level of the fracture site on the nail.
Nail diameter should be 33–40% of narrowest part of medullary canal.

3. Patient preparation and approach

Patient positioning

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.

Supine patient position


Expose the bone at both entry points.

Approach to the entry points

4. Opening the canal

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.

Opening the entry points

5. Nail insertion

Precontour both nails with the apex at the level of the fracture site.

The nail bend should be about three times the diameter of the medullary canal.

Precontouring the nails

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

Insertion of the first nail through the lateral entry point
Pearl: Insert the nail with the tip perpendicular to the shaft axis until the far cortex is felt. Rotate the nail 180° and advance it using the curved side of the tip.
If the tip is stuck in the far cortex and cannot be advanced, remove the nail and bend the tip to give a slightly more pronounced curvature.
Pearl: A short working length (3–5 cm) between the entry point and the inserter improves control of the nail during insertion.
Pearl for nail insertion

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

Pearl: Use a T-handle on the medial nail to act as a joystick reduction tool. This also avoids changing the inserter from one nail to the other.
Insertion of second nail
Pitfall: Make sure that the second nail has not crossed the first more than once to avoid the corkscrew phenomenon.
If this happens reinsert a new nail.
Pitfall: corkscrew phenomenon

6. Proximal fragment advancement

Reduce the fracture freehand, with a reduction tool or with a fracture table.

Advance both nail tips with an oscillating maneuver past the fracture site into the proximal fragment.

Use the nails as joysticks to reduce the main fragments.

Advancing the nails past the fracture site into the proximal fragment

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

Reduction with F-tool

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

Reduction with Steinmann pin

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

Open reduction through a limited lateral approach

Assessment of rotational alignment

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.

7. Final seating

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.

Final seating of nail tips

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

Advancing the nails into femoral neck and greater trochanter with proximal fractures

Pitfall: penetration of femoral neck

Take care not to advance the medially introduced nail too far and thereby penetrate the femoral neck.
Use lateral image intensifier views to confirm correct position.
Pitfall: penetration of femoral neck

8. Cutting the nails

Cut the nails with the dedicated nail cutter.

Cutting 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.

Retracting the nails for cutting with common cutter
Pearl: Bend the nail to just elevate it from the bone as this facilitates removal. Further bending is not recommended as it may cause skin irritation.
Excessive bending leading to skin irritation

End caps

End caps are not recommended in transverse fractures as they may prevent fracture compression with weight bearing.

Final nail position without end caps

9. Final assessment

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

Obtain final AP and lateral fluoroscopic views.

Checking the range of internal and external leg rotation

10. Aftercare

Immediate postoperative care

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.

Ambulation with crutches on first postoperative day


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

Neurovascular examination

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 care

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.

Clinical assessment of leg length with tape measure form ASIS to 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.

Leg length measured in a long-leg x-ray from femoral head to ankle joint

Implant removal

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.