Bone-holding forceps are applied to the proximal and distal fragment for distraction. This is necessary to counteract the strong muscles surrounding the bone.
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 facilitate implant selection, to reduce operating time.
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, temporary stabilization is achieved using K-wires through the locking drill guide in each of the fragments. 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.
If a straight plate is applied to a straight bone, compressive forces are greatest directly underneath the plate. At the far cortex a small gap results due to tension.
Pitfall: Compression plates must be prestressed to produce a 1-2 mm gap between the plate and the bone at the fracture sites. Over bending of the plate at the fracture lines ensures even compression across the fracture lines.
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.
By applying tension, the overbent plate is straightened, which leads to compression of the opposite cortex, so that finally the whole fracture is firmly closed and compressed.
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.
Phase 1: 1-3 day after surgery
The aim is to reduce the edema, inflammation and pain and to protect the surgical wound. A compressive bandage or modified Robert Jones bandage can be used. Integrative medical therapies, anti-inflammatory medications (note in the cat that many are toxic; only use drugs labeled for cats) and analgesics are recommended. In most cases, 10-20 minutes of ice therapy is recommended every 8 hours, but maybe challenging in cats.
Phase 2: 4-10 days after surgery
The aim is to resolve the hematoma, edema and control pain, and prevent muscle contracture. Analgesic medications may still be needed. Anti-inflammatory medications used in the cat are not labeled for continued use after a few days and should be avoided. Rehabilitation and integrative medical therapies can be used.
If the cat 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.