Intramedullary (IM) nailing is the first treatment choice for most tibial shaft fractures because it offers durable fixation, often with sufficient stability for weight bearing. IM nailing has been proven successful in many clinical settings. Nail fixation provides relative stability and promotes indirect healing with callus. With moderate soft-tissue compromise, nailing is often a viable option while plating may not be possible.
Proximal and distal locking screws improve IM nail fixation by providing rotational and axial stability, and permitting nailing of more proximal and distal fractures.
Nailing without image intensification
Image intensification is routine for IM nailing, when available. However, tibial nailing can be done without it, but with modified techniques. Attention must be paid to
Choosing a proper entry site
Reducing the fracture
Passing the nail across the fracture site
Ensuring proper nail length
Inserting distal locking screws.
Exposure of entry site, open reduction of the fracture, preoperative planning, and special distal locking guides are valuable aids.
Determining nail length
Nail length must be determined preoperatively. If one tibia is intact, a tape measure, or x-ray techniques can be used. The proper length nail must be available, and an assortment of nails may be helpful if measurement errors occur. Too long a nail may distract the fracture, or be too prominent. Too short will compromise fixation.
Determining nail diameter
The nail diameter must fit through the narrowest part of the tibial shaft, which may be increased by intramedullary reaming. Diameter gauges may be used with both AP and lateral radiographs, but magnification errors might exist. The curvature of the tibia and the nail may differ, so that a nail of the measured diameter may not be insertable. Reamers, or smaller nails, may be required.
AO teaching video: Universal Tibial Nail and SynReam
AO teaching video: The aiming device
Delayed reduction If nailing will be delayed, a temporary external fixator can maintain distraction, thus aiding reduction. If the fracture consolidates with shortening, it will be difficult to achieve closed reduction, particularly after 10-15 days. An initial attempt at closed reduction may be tried, but if unsuccessful, proceed directly to open reduction.
Initial reduction for guide wire
The fracture must be reduced to permit passage of the guide wire. A slight bend just above the ball tip may aid passing the wire through the fracture zone. Reduction for guide wire may be possible with traction and manual manipulation. If not, open reduction will be required.
Usually, two people are required to perform manual traction. One person holds the leg and the other exerts traction by pulling the leg and controlling the reduction by palpating the tibial crest and the anteromedial surface.
Using a distractor
A large distractor is usually placed in a coronal plane. It lies posterior to the tibia, either laterally or medially. Do not obstruct planned locking screws.
The proximal Schanz screw must be proximal and sufficiently posterior to avoid blocking the nail. Place it parallel to the tibial plateau to aid proximal fracture alignment. The distractor’s distal pin should be outside the intended nail location, posteriorly in the distal tibia, or in the talus.
An external fixator is an alternative for the distractor. Pin placements are the same.
Incision Locate the fracture by palpation. Make a small incision over the fracture. Extend the incision sufficiently to access the fracture. Free up one side of the fracture site at a time with minimal dissection.
Transverse fractures If the fracture is transverse, it may be reduced with manipulation using clamps on the bone ends, which often require excessive exposure. Percutaneous Schanz screws are less invasive. The technique is as follows: Free up the ends of both fracture fragments. Align the crest of both fragments. This will assure proper rotation. Flex the fracture to 45 degrees, or enough to place one fragment onto the other. Approximate the cortical edges, and gradually straighten the fracture, which compresses the fracture site. Check rotation.
Oblique fracture If the fracture is oblique, a bone clamp can be used to compress the fractures, which may restore appropriate length.
Alternatively, a Hohmann retractor can be used for reduction by placing it between the fracture fragments and prying them apart. It is important to hold this position for at least 30 seconds in order to stretch the tissues.
It is very important to maintain the reduction while the nail is inserted. This often requires an assistant, or temporary use of distractor, external fixator, or plate with unicortical screws.
The smallest universal nail has a 10 mm external diameter. This is too big to be inserted into many tibias without the use of intramedullary reaming. Cannulated reamers with flexible shafts are used over a ball-tipped guide wire that is placed through the reduced fracture. Noncannulated reamers are another option, and are used directly without a guide wire. Whichever technique is used, the fracture must be kept reduced during reaming.
Guide wire placement
Once the guide wire is inserted all the way to the tibial plafond, significant bony resistance is usually felt, except with severe osteoporosis. If imaging is not available to confirm guide wire placement, a second guide wire of the same length can be placed parallel to the intramedullary one, along the surface of the lower leg, and its tip should lie above the palpable ankle joint. Additionally, the length of the medullary canal can be checked by using a second guide wire (of equal length), held adjacent to the intramedullary wire, and with its tip placed in the entry site. The length of the second guide wire protruding above the first guide wire is equivalent to the length of the guide wire within the medullary canal. This reconfirms the appropriate nail length.
Start with the smallest reamer bit, and serially enlarge the medullary canal with increasing diameter reamers until mechanical contact is made over an approximately 6 cm segment of the medullary canal isthmus. The appropriate nail diameter, estimated from preoperative x-rays, should be large enough for strength and durability, and usually approximately 1.5 mm smaller than the final reamer bit. It is important that the nail fits easily through the medullary canal, and if it does not advance readily, it should be withdrawn and additional reaming carried out.
Hand reamers (non-cannulated)
With the fracture reduced, the medullary canal is enlarged by serially passing hand reamers by increasing diameter. Once you feel loose bone contact of the reamer within the intramedullary canal for approximately 6 cm, the reamer diameter usually indicates an appropriate nail diameter. Advance the reamer until it lies at the desired location for the tip of the nail, usually just above the subchondral bone. The correct length for the nail is indicated by the length of the reamer inserted into the bone, if the fracture is not distracted. It is important that the nail fits easily through the medullary canal, and if it does not advance readily, it should be withdrawn and additional reaming carried out.
4. Mounting the insertion instrument
Instrumentation for Universal Tibial Nail
We illustrate one of many available intramedullary nails. The instruments are specific for a given nail, and the surgeon must be familiar with the chosen system and follow its instructions.
Universal Tibial nail assembly
The conical bolt A is screwed into the proximal nail.
Tighten the conical bolt A.
The insertion handle B is inserted over conical bolt A and is placed on the nail so that the tabs on the insertion handle fit into corresponding notches on the nail. The insertion handle should be placed on the side through which the proximal locking screws will be inserted (usually medially).
Secure the insertion handle with the locking nut C.
Attach the driving head (E) to the curved driving piece (F). Attach the driving assembly to the conical bolt so that it orients the driving force parallel to the long axis of the tibia (i.e. distal portion of the nail). Tighten the assembly.
5. Nail insertion
Insert the IM Nail into the hole in the proximal tibia. Be sure the nail is properly placed in the entry site, and is also aimed towards the medullary canal. Protect the skin with retractors, or instruments, as necessary. Remember that the knee must be sufficiently flexed (>90 degrees) to allow proper nail alignment. Advance the nail to the fracture site, making sure that it follows the desired path.
Alignment during nail insertion
The fracture must be aligned satisfactorily for nailing to avoid comminution as the nail is driven through the fracture zone. Merely positioning the distal segment so that the tip of the nail enters it, and allowing the nail to align the tibial axis works well in the mid-diaphyseal region. However, rotation should be correct as the nail crosses the fracture. Length must also be adjusted as the nail is inserted to avoid either shortening, or distraction of the fracture. While fractures in the narrow portion of the medullary canal usually align well with nail insertion, proximal and distal fractures require special efforts from the surgeon to avoid angulation.
Distraction aids Unless a tibial fracture is quite stable, it must be supported in some way while the nail is inserted. Manual distraction is possible, but often awkward. A fracture table, or devices such as the large bone distractor, or external fixator, are valuable aids. Initial distraction helps align the fracture site. As the nail is advanced distally, resistance must be provided to maintain bone contact at the fracture. As the nail is advanced, rotation should be correct because it may become blocked by the nail.
Advance nail past fracture site
Now fully insert the nail. After the nail passes through the fracture site, stabilize the foot on the OR table to maintain reduction without distraction as the nail is advanced.
6. Calibration of the distal aiming device
Mounting the Double Joint for Aiming Beam
Attach the Double Joint for Aiming Beam to the most distal hole of the insertion handle, and screw the large star-shaped nut tight by hand. Slide the Aiming Beam for ModAD, length 249 mm, through the black spacers of the Double Joint for Aiming Beam. Tighten the nut above the black spacers by hand so that the beam is still able to slide, and the joint on the interface is able to rotate.
Visually align the aiming beam-double joint roughly with the axis of the nail and insert the twin calibration pin through the two holes of aiming beam head. Take the end of the aiming beam head with the inserted twin calibration pin in one hand and the double joint in the other hand, and align the pins to the holes until they fall into the holes, without any friction. Tighten the nut of the double joint by hand. Check the calibration by moving the twin calibrating pin up and down until they fall into the locking holes of the nail without resistance. Only then tighten the nut of the double joint with the combination wrench 11 mm.
Placing the T- and L-spacers
Place sequentially T-spacer and L-spacers (L-spacer small and L-Spacer medium) into the distal hole of the spacer arm. The medullary canal and the cortical bone thin distally allowing easier penetration and re-contact to the nail as well as avoidance of important anatomical structures. Tighten the upper nut of the L-spacer by hand onto the spacer arm hole. Slide the carriage until the mid-length of the L-spacer foot is in line with the nail. Tighten the large black screw of the spacer arm.
Note: Ensure that the L-Spacer contacts the nail. Ensure that the Twin Calibrated Pins go through the holes freely in the final calibration. Tighten the double joint with the combination wrench with the L-spacer contacting the nail.
Remove the assembled Aiming Device from the aiming arm by opening the star-shaped nut and lay it aside. Do not loosen any other parts or calibration will be lost!
7. Distal locking
Drill hole for L-/T-Spacer
Re-attach the calibrated ModAD aiming construct to the most distal hole in the insertion handle/aiming arm. Tighten the starshaped screw of the double joint by hand. Hold the ModAD construct roughly parallel to the shaft axis for drilling an L-spacer hole that is perpendicular to nail and bone. Insert the golden drill sleeve 8.0/6.0 with the golden trocar. 6.0 mm into distal open guide hole in the carriage. Remove the trocar. Drill with the 6.0 mm drill bit until the safety stop. If you have enough space, tilt the Aiming Beam assembly upward. If this is not possible, remove the entire ModAD aiming construct by loosening the star-shaped screw.
Note: Do not loosen the cylindrical nut holding the aiming beam to the double joint or calibration will be lost!
Drill additionally with the 6.0 mm flat-tipped drill bit to ensure that the cortex has been completely opened.
Clean opening for L-Spacer with L-/T-curettes
Mount the handle with Quick Coupling onto the chosen curette and insert it into the opening. With rotating movements remove cancellous bone from the opening, in order to achieve a clean contact with the surface of the nail.
Mount the handle with Quick Coupling onto the chosen L- or T-spacer, depending on the canal space: Insert the L-spacer into the nail contact opening and place the foot of the L- or T-spacer on the anterior radius/edge of the nail. If the L- or T-spacer is correctly placed, the notches at the foot of the spacer will make a soft metallic clattering sound when gently moved across the nail to confirm nail-spacer contact.
Note: If there is no contact between the foot of the L-spacer and the nail, try turning the foot 180°. If contact with the nail still cannot be established, use a larger L-spacer.
Verify that the L-spacer is not through the interlocking hole of the nail by turning the L-spacer 180°. Tilt down the Aiming Beam construct and connect the L- or T-spacer to this assembly into the distal open guide hole in the carriage. Tighten the clamping nut firmly by hand.
Drill the hole for standard distal locking
The ModAD must be used with the ModAD protection sleeves, drill sleeves and drill bits since those from the standard nailing systems are too short. ModAD drill sleeve assemblies are color-coded with locking bolts.
Use the ModAD 4.5 mm drill sleeves/trocar/protection sleeves and 4.5 mm drill bit. Drill the most distal locking hole first. Insert the trocar through the protection sleeve to indent the bone. Remove the trocar. Drill through both cortices and leave the drill bit in the bone. This will stabilize the ModAD construct.
Drill the proximal hole, drilling through both cortices. Remove the drill sleeve and drill bit. Measure the length and insert the screw. Now remove the drill bit from the distal hole, measure for length and insert the distal screw. Then remove the ModAD.
8. Proximal locking
Do the proximal locking according to the specifications of the manufacturer. It is advisable to use 2 proximal locking screws.