Bone-holding forceps are applied to the proximal and distal fragment for distraction. This is necessary to counteract the strong muscles surrounding the bone, particularly in large breed dogs.
The fracture ends are elevated, toggled and then replaced back into reduction.
Alternatively, a Hohmann retractor or similar instrument can be used as a lever to bring the fragments into alignment.
The length of the plate should allow placement of at least three or four screws in each major fragment.
Although the medial surface of the tibia is relatively flat, contouring of the plate must be performed to match the shape of the bone. Precontouring of the plate to radiographs of the sound contralateral limb can help to facilitate implant selection, to reduce operating time, and to ensure that the S-shaped curve of the tibia is reproduced thus avoiding valgus deformities.
Weight bearing forces along the mechanical axis cause bending forces on the tibia. These bending forces cause tension on the medial surface of the tibia. Tension forces are converted into compression forces by placing the plate in compression on the medial surface.
Following contouring, the plate is applied to the medial surface of the bone and secured with at least two bone-holding forceps.
Note: It is important to use plate holding forceps to ensure the plate does not shift when drilling and placing the screws causing loss of reduction at the fracture site.
Anatomical reduction is carefully checked. If required, the alignment is corrected and the bone-holding forceps are repositioned.
If a locking compression plate is used, a push-pull device can be inserted in both the proximal and distal fragment to achieve temporary plate stabilization instead of bone-holding forceps.
With this temporary fixation in place, the plate position and anatomical reduction is checked thoroughly and adjusted, if required.
A screw is inserted after drilling with the neutral or load guide through the plate on one side of the fracture line. The screw is not fully tightened.
Note: Compression plates must be over bent to produce a 2mm gap between the plate and the bone at the fracture site. This will ensure even compression across the fracture line.
Pitfall: It is important to obtain load-bearing contact between the lateral tibial cortices as the screws are tightened. In order to achieve that, the plate must be prestressed prior to application.
A second screw is inserted after drilling with the load guide on the other side of the fracture. The screws are tightened in an alternating fashion, generating compression across the fracture line.
The most distal and most proximal screws are now inserted in a neutral fashion.
All remaining plate screws are inserted in a neutral mode.
Note: It is possible to use the load guide for up to two screws on either side of the fracture line to achieve compression. This is rarely necessary and it is possible to over compress the bone.
It is not necessary to fill all the plate holes available.
In a well-compressed transverse or short oblique tibial fracture, two reliably tightened screws close to either side of the fracture line and two near to each end of the plate represent a stable configuration that can be augmented by further screws according to the individual situation.
Fixation with a locking compression plate
When using a LCP as a compression plate, the plate must be contoured to match the bone anatomy. Failure to do so can lead to displacement of the fragments or malalignment when the non-locking screws are tightened.
It is not necessary to use any locking screws for compression plating. If a locking compression plate is used, compression across the fracture must be achieved with non-locking screws before the locking screws are added.
If a combination of non-locking and locking screws is used, the surgeon should keep in mind that the non-locking screws must always be inserted and fully tightened before any locking screw insertion occurs.
4. Case example
3 month old, male, mixed breed dog with a 42-A3 fracture.
The fracture was repaired with a 2.7mm DCP applied in compression.
Radiographs taken four weeks following surgery show complete healing of the fracture with continuation of growth of the tibia.
Phase 1: 1-3 day after surgery
The aim is to reduce the edema, inflammation and pain. A Robert Jones or modified Robert Jones bandage can be used to decrease the edema and protect the surgical wound. Integrative medical therapies, anti-inflammatory medications and analgesics are recommended. In most cases, 10-20 minutes of ice therapy is recommended every 8 hours.
Phase 2: 4-10 days after surgery
The aim is to resolve the hematoma, edema and control pain, and prevent muscle contracture. Anti-inflammatory and analgesic medications may still be needed. Rehabilitation and integrative medical therapies can be used.
If the dog is not starting to use the limb within a few days after surgery, a careful evaluation is recommended.
10-14 days after surgery the sutures are removed.
Phase 3: 10 day-bone healing
Radiographic assessment is performed every 4-8 weeks until bone healing is confirmed.
More information about implant removal can be found here.