1 Principles top
Oblique fractures of the tibial diaphysis can be treated nonoperatively if the initial displacement is small and there is <1 cm shortening.
Operative treatment with a nail
Nailing is usually a good option for tibial fractures, but is technically more difficult for proximal and distal locations.
Operative treatment with plate and screws
For the treatment of simple oblique fractures in the diaphyseal area, absolute stability is recommended.
For this, anatomical reduction and interfragmentary compression are necessary.
Choosing the method of interfragmentary compression
The method of interfragmentary compression is determined by the fracture geometry and the plane of the obliquity.
1. The tip of the fracture is in the center of the anteromedial or anterolateral surface of the tibia
In this case, the fracture can be compressed with an axial compression plate, with a supplementary lag screw through the plate.
The apex of the fracture should be underneath the plate.
2. The tip of the fracture is not in the center of the anteromedial or anterolateral surface, but either posterior or anterior
In this case, compression must be done with a lag screw, usually inserted through the plate. In this case, the plate is used in protection rather than compression mode. The apex of the fracture is not underneath the plate, but either anterior or posterior of it.
3. The tip of the fracture lies on the tibial crest
In this case, a lag screw outside of the plate (protection mode) is usually required.
2 Open reduction topenlarge
As anatomical reduction is necessary, open, or direct, reduction is needed.
Mobilize just enough of the periosteum around the fracture edges to display the reduction. Leave as much of the periosteum as possible on the rest of the bone.
Because they do less damage to the soft tissues, pointed reduction forceps are best used both for grasping bone and for compressing the fracture.
In a first step, length and rotation must be restored. This may be possible with manual traction. Otherwise, mechanical aids such as a large distractor, or bone spreader, should be considered.
Reduction of the fracture
In a second step, once length and rotation are restored, pointed reduction forceps are used to compress and anatomically reduce the fracture. The forceps tips should be applied perpendicular to the plane of the fracture, just like a lag screw.
Alternative: indirect reduction with the plate
In minimally displaced fractures, the fracture can be reduced with the plate. To do this, follow these steps:
- Determine the position of the plate as described above.
- Drill the first hole as close as possible to the fracture line, using a 3.2 mm drill bit. (Alternatively, this hole can be drilled before fracture reduction.)
- Measure for screw length using a depth gauge and add 4 mm for the plate.
- Tap using the 4.5 mm tap and appropriate drill sleeve.
- Apply the plate and tighten the screw.
This usually reduces the fracture.
3 Confirm fracture plane topenlarge
Before starting with this fixation method, be sure that the plate can be placed exactly over the tip of the fracture. This is only possible if the fracture tip is centered on the tibial surface where the plate will be placed.
4 Preparation topenlarge
Plate selection and preparation
The chosen plate (usually a narrow, 4.5 mm DCP) should allow
1. screws 1 and 2 to be placed proximal and distal of the fracture, and screw 3 to be placed centrally and perpendicular to the fracture, as illustrated.
2. at least 3 additional screw holes proximal, and 3 screw holes distal of the fracture site.
Usually a 9-10 hole straight narrow 4.5 mm DCP is used.
Remember that whenever the plate is placed distally, the plate must be twisted and bent to match the shape of the tibia in that region.
Planning the plate position
Before starting with the procedure, the location (proximal/distal) of the plate is determined according to
a. The position of the first screw in relation to the fracture tip
The first screw must be placed as close as possible to the fracture defect (screw 1 in illustration).
b.The position of the lag screw
The lag screw (screw 3 in illustration) should be inserted as perpendicular as possible to the fracture plane. If it is not possible to insert the lag screw perpendicularly to the fracture plane, at least insert it through the center of the fracture.
Overbending the plate
To compress the opposite cortex, the plate should be slightly overbent (more convex) at the fracture, so there is a small gap between plate and bone. This causes the cortex opposite the plate to be compressed first, as the eccentrically placed plate screws are tightened. With further tightening, the near cortex of the fracture becomes compressed. This short, convex (away from the bone) bend can be made with the handheld bending pliers, or a pair of bending irons.
If axial compression is applied in a transverse or short oblique fracture with a plate that is not overbent, compression first occurs at the cortex under the plate. This causes a gap in the fracture opposite the plate, with resulting instability. Such a gap must be avoided.
Overbend the plate
Use bending irons to overbend the plate 1-2 mm. The bent should be located just over the fracture.
5 Fixation topenlarge
Planning the first screw
An oblique fracture line forms an obtuse angle and an acute angle under the plate, as illustrated on this AP view.
One must attach the plate first to the bone fragment which forms the obtuse angle. Thus the plate prevents displacement along the fracture plane.
The first screw is inserted on the side of the plate where the fracture forms an obtuse angle with the plate. This forms a space between the plate and fracture line into which the acute-angle fragment fits. This will prevent excessive shortening during compression.
When compression is applied by tightening the second (eccentric) screw on the opposite side of the fracture, the plate traps the illustrated distal fragment, and converts axial compression to fracture plane compression.
Insert the first screw
Drill with a 3.2 mm drill bit and neutral drill guide through the plate hole as close as possible to the tip of the fracture. Measure for screw length, tap with a 4.5 mm tap and a protective sleeve and insert the first screw, but do not fully tighten it yet. (Alternatively, this hole can be drilled before the plate obscures the fracture site.)
Axial compression with eccentric screw
Now, with the fracture reduced and plate properly positioned, drill eccentrically (load position) for the second screw. Then measure and tap as described above.
Insert the eccentric screw and alternately tighten both screws, compressing the fracture.
Drilling the gliding hole for the lag screw
Using a 4.5 mm drill guide and a 4.5 mm drill bit, drill a gliding hole in
the near cortex.
Ensure that the direction of the drill is as perpendicular to the fracture plane as possible. If this is not possible, ensure that the lag screw will go through the center of the fracture.
Drilling the thread hole
Insert the 4.5 mm / 3.2 mm drill guide through the plate and the gliding hole. Use a 3.2 mm drill bit to drill a thread hole just through the far cortex.
Measure for screw length
Use a depth gauge through the plate to measure for screw length.
Measure the longer side of an oblique drill hole, as shown, to ensure sufficient screw length.
A screw should protrude 1-2 mm through the opposite cortex to ensure thread purchase. However, too long a screw may be tender, or injure soft tissues.
Tap the thread hole
Use a 4.5 mm tap and the corresponding drill sleeve to tap the thread hole.
Insert lag screw
Insert the lag screw and carefully tighten it.
This increases both the compression and the stability of the construct.
Insertion of diaphyseal fixation screws
Insert the screws alternating between the proximal and distal fragments. Start with the screws closest to the fracture plane and work your way outwards.
Drill for the fixation screws. At least 3 screws should be used on the proximal fragment, and at least 3 screws on the distal fragment.
For all diaphyseal screws, use cortical screws, observing the following steps:
- Drill both cortices using the appropriate drill guide to ensure a central drill hole with the 3.2 mm drill bit.
- Measure for screw length.
- Tap both cortices using the 4.5 mm tap and appropriate drill sleeve.
- Insert the screw.