Authors of section


Peter V Giannoudis, Hans Christoph Pape, Michael Schütz

Executive Editors

Chris Colton, Rick Buckley

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Antegrade nailing

1. General considerations

Reamed versus unreamed nailing

In general, reamed nailing allows the use of larger diameter implants and may therefore provide greater initial stability. Some studies show a tendency towards less malunion and nonunion when reaming is performed. On the other hand, fat embolization is a concern and with the solid unreamed nails, the forces required to achieve nail torsion are higher. Most centers prefer reamed nailing as the standard procedure.

For bone graft while reaming, see Frequently Asked Questions about the Reamer Irrigator Aspirator system.

Note on illustrations

Throughout this treatment option illustrations of generic fracture patterns are shown, as four different types:

A) Unreduced fracture
B) Reduced fracture
C) Fracture reduced and fixed provisionally
D) Fracture fixed definitively

antegrade nailing

2. Patient preparation

3. Antegrade nailing approaches

The piriformis entry point is used for straight nails.

The trochanteric entry point is used for proximally curved nails.

4. Reduction

General considerations

In more proximal fractures, due to the pull of the iliopsoas muscle, the upper main fragment may be flexed and externally rotated, and the distal segment lies posteriorly due to gravity.

Reduction is performed under image intensification.

Several options for fracture reduction can be considered:

  • Elevation of the distal fragment by use of a crutch.
  • Lowering of the proximal fragment by external pressure from a mallet.
  • A wrap around the femur.
  • A Schanz screw inserted into one of the fragments.
  • Use of a bone hook.
  • (Manual reduction)
  • Poller screws
antegrade nailing

Elevation of the distal fragment by use of a crutch

This option may only be used if the patient is on traction. A crutch is slid beneath the distal main fragment to elevate it to the level of the proximal fragment.

Antegrade nailing – Subtrochanteric femoral fracture – Elevation of distal fragment

Lowering of the proximal fragment by external pressure from a mallet

Firm manual pressure is usually required to achieve fracture reduction.

Femoral shaft – Reduction using mallet

A wrap around the femur

Based on the nature of the fracture, the wrap is usually placed around the larger fragment.

Femoral shaft – Reduction using wrap

A Schanz screw inserted into one of the fragments

A monocortical Schanz screw (preferably 5 mm) can be helpful for providing direct control of the displaced fragments. It is superior to reduction maneuvers through the skin.

Femoral shaft – Reduction using Schanz screw

Bone hook

Direct reduction with a bone hook may be helpful for securing an anatomic alignment. Careful insertion and manipulation must be performed, to minimize soft-tissue trauma and to prevent injury to the femoral artery.

Femoral shaft – Reduction using bone hook

Reduction using a bone hook with minimal incision is advised.

Femoral shaft – Reduction using bone hook

Manual reduction

Manual reduction may be attempted, but radiation of the surgeon‘s hands may be unavoidable.

Guide wire insertion

A guide wire is advanced into the distal main fragment until it is about 5 mm proximal to the intercondylar notch. It is important that the guide wire be centered to prevent eccentric reaming and subsequent malposition of the nail, which can result in varus/valgus/antecurvatum/retrocurvatum malalignment.

Unreamed nailing does not require a guide wire. When unreamed nailing is performed, the nail is used as a reduction tool.

Femoral shaft – Antegrade nailing – Guide wire insertion

Guide wire inserted down the femur before reduction of femur shaft and nailing.

antegrade nailing

To ensure maintenance of alignment of the K-wire throughout the reaming process, it may be gently tapped to provide purchase in the cancellous subchondral bone. If this is not achieved, the guide wire may displace on removal and exchange of the reamers.

Antegrade nailing – Subtrochanteric femoral fracture – Correct guide wire insertion

Teaching videos

AO teaching video: Femur - Shaft fractures - Intramedullary Nailing with the Antegrade Femoral Nail (AFN)

AO teaching video: Femur—Shaft fracture 32-B2 Intramedullary nailing with the Expert Lateral Femoral Nail (LFN)

5. Poller screw (blocking screw)

General considerations

The concept of a poller screw is based on the principle that the malalignment induced by oblique, proximal and distal fractures can be counteracted by the nail-directing effect of the screw. Therefore, its position should aim to counteract the displacement of the fracture. Most often it is therefore placed in the short side in the distal fragment. If there is a wide canal, two screws can be placed on either side of the path of the nail.

It is advisable to insert the poller screw prior to reaming, and in case of unreamed nailing, prior to nail insertion, to provide adequate contact between the nail and the screw. If the poller screw is inserted after reaming, the path of the nail is already set and the poller screw may not work. A small fracture screw or a locking screw can be used as a poller screw, depending on the local anatomy.

The reaming process in the presence of the poller screw must be performed very carefully in order not to harm the reamer tip.

The most frequent indication for poller screws is a proximal or distal oblique fracture which tends to shift when the axial knee blow technique is used to close any fracture gap, or when the patient is mobilized.

In these cases, prophylactic poller screws are very helpful.

See also:
Stedtfeld HW, Mittlmeier T, Landgraf P et al. The Logic and Clinical Applications of Blocking Screws. J. Bone Joint Surg. Am. 2004; 86-A Suppl 2:17-25.

Midshaft comminuted fractures

Poller screws are used according to the initial displacement and the size of the canal. In general, midshaft fractures tend to align better than more proximal or distal fractures and, therefore, the indication for poller screws is uncommon.

Poller screw (blocking screw) in midshaft fractures

6. Determine nail length and diameter

Determine nail length via guide wire (only with reamed nailing)

The correct length of the nail is determined by comparing a second guide wire to the one that has been inserted. The correct placement of the guide wire in the distal canal should be assessed via image intensifier. Additionally, the second guide wire must be positioned in contact with the greater trochanter. This must be verified by image intensifier as well.

Femoral shaft – Antegrade nailing - Nail length and diameter using guide wire

Radiographic ruler

Alternatively, a radiographic ruler may be used.

The tip of the ruler should be positioned in the center of the distal end of the femur. Nail length is determined by the position of piriformis fossa, not by the tip of the greater trochanter.

Femoral shaft – Antegrade nailing - Nail length and diameter using radiographic ruler

It is important to visualize the fracture zone by image intensifier to ensure that adequate restoration of femoral length has been achieved.

Femoral shaft – Antegrade nailing - Nail length and diameter using radiographic ruler

Nail diameter

It is important to measure the medullary diameter at the mid portion of the femur, which represents the narrowest segment of the medullary canal.

The inner cortical edge should touch with the inner numbered disk of the ruler aperture. In the illustration an inner cortical diameter of 14 mm is shown.

Femoral shaft – Antegrade nailing - Nail length and diameter using radiographic ruler

Consideration for special situations

In multifragmentary fractures, or in open fractures with bone loss, it is safer to perform preoperative planning on the uninjured leg. In bilateral femoral fractures, the less comminuted side should be used to determine the length and diameter of the nail.

7. Reaming

Insertion of reaming rod

After the tissue protector has been introduced, the reaming shaft, fitted with the first reamer head, is inserted over the guide wire. Usually reaming begins with a 9 mm medullary reamer.

Femoral shaft – Antegrade nailing – Insertion of reaming rod

Sequential reamer size increase

Reaming is performed in sequential steps by increments of 0.5 mm each.

As soon as chatter from cancellous bone can be felt and heard, the inner cortex has been reached. This may not be the case in segmental fractures or when severe comminution is present.

Adequate reaming must be performed to allow for smooth nail insertion. For example, for a nail width of 10 mm, drill bits of up to 10.5 or 11 mm diameter are used. If a very tight fit of the reamer can be detected before the desired reaming size is reached, one should consider using a smaller nail than previously planned.

Femoral shaft – Antegrade nailing – Sequential reamer size increase

Pitfall 1: Eccentric reaming

Eccentric reaming can cause weakening of the adjacent cortex which may interfere with healing or even cause a fatigue fracture.

Pitfall 2: Trapping of reamer by slow spinning
If the reamer becomes trapped while reaming, it must be gently removed by the most senior surgeon, because breakage of the reamer tip in this situation can be a devastating complication.

Pitfall 3: Heat necrosis by overaggressive reaming
Overaggressive reaming should be avoided because it may cause heat necrosis of the femoral canal. This applies especially for narrow midshaft canals (9 mm or less in diameter).

Pitfall 4: Rapid thrusting/systemic fat embolization
Care should be taken to use sharp reamers, to advance the reamers slowly, and to allow sufficient time between reaming steps for the intramedullary pressure to normalize. Rapid thrusting of the reamer may worsen the intramedullary pressure increase that is observed during nailing. This image demonstrates fat extrusion in a human cadaver specimen with a window in the proximal section.

Femoral shaft – Antegrade nailing – fat embolization during reaming

This may cause pulmonary embolization of medullary fat, which in turn may lead to pulmonary dysfunction (lower image in the enlarged view shows an example of fat embolization through the right atrium).

Femoral shaft – Antegrade nailing – Reaming

Special situation: conversion from an external fixator to an intramedullary nail

Because the external fixator is still in place, the Schanz screws must be partially withdrawn to allow the guide wire, the reamers, and later the nail, to pass through. The external fixator is held in place by monocortical purchase to assure that the fracture remains stable. The external fixator also acts as a joystick for the reduction.

Femoral shaft – Antegrade nailing – conversion from external fixator to intermedullary nail

8. Nail insertion

Connecting handle to nail

The insertion handle is connected to the nail by the corresponding connecting screw. It is attached using the hexagonal screwdriver through the hole in the insertion handle. It is recommended that the nail be inserted manually and rotated about 90 degrees from its point of entry to its final orientation.

Antegrade nailing – Subtrochanteric femoral fracture – Nail handle

Introduction of nail

Under control with the image intensifier, the nail is pushed down as far as the fracture zone. After the driving cap has been fixed to the insertion handle, the nail is further advanced into the medullary cavity by gentle hammer blows, whilst verifying the position of the tip of the nail under the image intensifier.

In this intraoperative view, the nail is about to pass the fracture site in the intensifier image.

Femoral shaft – Antegrade nailing – Nail introduction

In this intraoperative view an unreamed nail is inserted and the external fixator is used as a joystick to help to reduce the fracture anatomically.

Femoral shaft – Antegrade nailing – Nail introduction

Once past the fracture, the nail is advanced by hand or by gentle hammer blows.

Femoral shaft – Antegrade nailing – Nail introduction

Passing the fracture zone

It is important that the tip of the nail does not become trapped in the distal main fragment because blow out fractures can occur. Each gentle hammer blow should advance the nail. Do not force the nail through a tight canal – if necessary, re-ream to another 0.5 mm diameter.

In many cases, the nail will help to align the fracture.

Femoral shaft – Antegrade nailing – Nail passing fracture zone

A solid nail (unreamed technique) passes the fracture site into the distal medullary canal.

Nail insertion

Assessing proper nail insertion

The nail is then completely inserted. This is assessed by using an additional K-wire that marks the upper end of the nail.

Intraoperative photo of nail inserted with fracture reduced and mild distraction.

antegrade nailing

AP image of nail inserted in the proximal femur.

antegrade nailing

9. Nail locking

Purpose of locking

Locking was developed to provide and maintain rotational stability and length. It can also be used to finalize fracture reduction.

Static locking

Multifragmentary fractures are the least axially stable fractures. Special care must be taken to avoid limb shortening and static locking should be performed in all cases. The length may be assessed by comparison to the contralateral femur.

Femoral shaft – Antegrade nailing – Nail locking

10. Distal locking

Verification of nail position

Before locking, the correct position of the nail and the rotation of the femur must be verified.

If no traction table is used (ie, using the freehand technique) the cable method may be used. In this approach, a line is drawn from the iliac spine across the patella to the cleft between the first and second toes. If rotation is correct, this line will pass over the mid line of the patella. The radiological landmarks of the center of the femoral head, the center of the knee and the center of the ankle joint should all be in line if the mechanical axis of the femur is correct.

Another method of assessing rotational reduction is to compare the cortical thickness above and below the fracture. If a shaft fracture is multifragmentary, the image intensifier cannot be used to assess the analogue cortical diameter on both sides of the fracture.

Distal locking

Distal aiming

For distal locking, the image intensifier is brought into a strict lateral position. The distal hole must be seen as a perfect circle and the tip of a scalpel is projected into the center of the hole.

Distal locking

This guides the stab incision down to the femoral cortex.

Femoral shaft – Antegrade nailing – Distal aiming

Screw insertion technique

The radiolucent drive helps to position the drill bit so that the locking screw can be properly inserted. While the locking hole is drilled, the assisting surgeon must prevent the lower extremity from moving in order not to miss the target hole. The length of the locking screw is determined, using the appropriate depth gauge. Then the locking screw is inserted.

Femoral shaft – Antegrade nailing – Screw insertion for locking

If a radiolucent drive is not available, the projection of the tip of the drill bit should be placed as centrally as possible (see image). Start drilling but assess the position of the tip of the drill bit repeatedly, with the drill temporarily uncoupled.

Femoral shaft – Antegrade nailing – Screw insertion for locking

Pearl: If the contact between the screw driver and the locking screw is lost, the screw may move within the soft tissue and become extremely hard to capture. To prevent this time-consuming complication, the locking screw should be lassoed with a strong absorbable suture.

Pitfall: If the screw holes are not perpendicular to the nail, the locking screw may become trapped and may not be advanced properly.

Femoral shaft – Antegrade nailing – Screw insertion pearl

Second locking screw

The second locking screw is inserted into the distal locking hole. After distal locking, an axial blow to the knee region may be used to reduce any fracture distraction.

Alternatively, when distal locking is completed prior to proximal locking, a slotted hammer can be used to pull back the locked nail and the distal fragment.

Femoral shaft – Antegrade nailing – Second locking screw

Completed distal locking

The image shows the distal locking completed.

Femoral shaft – Antegrade nailing – Complete distal locking

Pitfall: screw loosening

Care should be taken to capture the far cortex to prevent toggling when the patient is mobilized. This would lead to early loosening of the locking screw. In the image shown, the proximal locking screw is of correct length, but the distal one is marginally too short.

Femoral shaft – Antegrade nailing – Screw loosening

11. Intraoperative radiological assessment

Assessment of rotation

The profile of the lesser trochanter is compared with that of the contralateral leg (lesser trochanter shape sign).

Before positioning the patient, the profile of the lesser trochanter of the intact opposite side (patella facing anterior) is stored in the image intensifier.

The illustration shows the lesser trochanter of the intact opposite side.

Femoral shaft – Nailing – Intraoperative radiological assessment


In cases of malrotation, the lesser trochanter is of different profile when compared to that of the contralateral leg.

Care should be taken to assess rotation with the patella facing directly forwards.

Femoral shaft – Nailnig – Intraoperative radiological assessment
Femoral shaft – Nailing – Intraoperative radiological assessment

Matching of the lesser trochanter shape

After distal locking, the correction is achieved by using the handle of the nail insertion device. Thereby the distal main fragment can be rotated in relation to the proximal main fragment.

Femoral shaft – Nailing – Roatation

Cortical step sign and diameter difference sign

The presence of considerable rotational deformity may be diagnosed by the difference in thickness of the cortices above and below the fracture zone.

The diameter difference sign is of use at levels where the bone cross section is oval rather than round. In cases of malrotation, the proximal and distal main fragments will appear to be of different diameters.

Femoral shaft – Nailing – Malrotation

12. Proximal locking

Proximal aiming device

If proximal locking is performed before distal locking, it is important to verify the correct position of the distal end of the nail under the image intensifier, before the proximal aiming device is attached to the insertion handle.

Femoral shaft – Antegrade nailing – Proximal aiming device

Preparation for screw insertion

The sites of the skin and fascial incisions for the drill bit and locking screws may be determined after the drill sleeve assembly has been in the holes of the aiming device.

The length of the locking screws is read from the calibrated drill bit. The correct length is confirmed antero-posteriorly using the image intensifier. The insertion handle should not be removed until the correct placement of all the locking screws has been verified.

Antegrade nailing – Subtrochanteric femoral fracture – Proximal locking

Drill sleeve to bone contact

The drill sleeve must be in close contact with the bone at all times since it is important for the measurement of the locking screws. Close contact is maintained by pressing down on the sleeve with the contralateral thumb.

Antegrade nailing – Subtrochanteric femoral fracture – Proximal locking

Fluoroscopy of proximal locking of femoral nail.

antegrade nailing

Verification of locking screw placement

A final x-ray in two planes should be obtained in all cases in order to verify the exact locking screw placement.

Here showing the final x-rays of a fragmentary segmental fracture.

Femoral shaft – Antegrade nailing – Proximal screw insertion
antegrade nailing

Special situation: associated femoral neck fracture

The system used for the ipsilateral femoral neck and shaft fracture must have the ability to biomechanically solve the midshaft femoral and femoral neck dilemma. This means that the nail must have at least two possibilities for screws into the femoral neck. Another option would be as shown in the diagram.

Femoral shaft – Antegrade nailing – Associated femoral neck fracture

Special situation: segmental fracture with extension to the subtrochanteric region

In cases of segmental fractures with extension to the subtrochanteric region the standard femoral nail with multiple proximal locking screws may be used.

Femoral shaft – Antegrade nailing – Extension of fracture into subtrochanteric region

Special situation: extension of fracture to the lesser trochanter

When a dedicated cephalomedullary device is not available and the fracture configuration permits, a 130° antegrade locking option can be considered.

Femoral shaft – Antegrade nailing – Extension of fracture into lesser trochanter

13. Insertion of end cap

An end cap may be used, depending on the final assessment of the nail length in relation to the tip of the greater trochanter.

The distance between the proximal end of the nail and the tip of the trochanter determines the appropriate length of the end cap, which is between zero and 20 mm, in 5 mm increments. The end cap is introduced using a hexagonal screwdriver.

The end cap is optional for the standard femoral nail.

Pitfall: The removal of the end cap may be very difficult if an exchange nailing is required. Bony overgrowth may require an extensive dissection of the greater trochanteric region. On the other hand, the end cap will have prevented tissue ingrowth and so, after its removal, the insertion of the extractor device is easier.

Femoral shaft – Antegrade nailing – Insertion of end cap

14. Wound closure and assessment of alignment

Wound closure

The procedure ends with the closure of the fascia and the skin as separate layers.

Femoral shaft – Antegrade nailing – Wound closure and assessment of alignment

Assessment of alignment

Before the patient is moved from the fracture table, rotation of the leg is observed clinically and compared to the contralateral leg.

With the femur now stable, it is possible to perform a thorough examination of the knee joint to rule out additional ligamentous injuries.

Femoral shaft – Antegrade nailing – Wound closure and assessment of alignment

15. Aftercare

Compartment syndrome and nerve injury

Close monitoring of the femoral muscle compartments should be carried out especially during the first 48 hours, in order to rule out compartment syndrome.

Postoperative assessment

In all cases in which radiological control has not been used during the procedure, a check x-ray to determine the correct placement of the implant and fracture reduction should be taken within 24 hours.

Functional treatment

Unless there are other injuries or complications, mobilization may be started on postoperative day 1. Static quadriceps exercises with passive range of motion of the knee should be encouraged. If a continuous passive motion device is used, this must be discontinued at regular intervals for the essential static muscle exercises. Afterwards special emphasis should be placed on active knee and hip movement.

Weight bearing

Full weight bearing may be performed with crutches or a walker.


Wound healing should be assessed regularly within the first two weeks. Subsequently a 6 and 12 week clinical and radiological follow-up is usually made. A longer period may be required if the fracture healing is delayed.

Implant removal

Implant removal is not mandatory and should be discussed with the patient, if there are implant-related symptoms after consolidated fracture healing.