Step 5: Why TPLO
The tibial plateau leveling osteotomy (TPLO) is one of the original osteotomy (bone cut) techniques and has been used in practice for over 20 years, with nearly 200 research articles published on the topic. This surgery requires making a semi-circular bone cut at the top of the tibia, which includes the weight-bearing portion of the bone, or the tibial plateau. Following osteotomy, this small section of bone is rotated to allow a reduction of the tibial plateau slope (TPS, an average of approximately 25° in dogs) to approximately 5-7°. The two segments of bone are then stabilized with a plate and screws until the bone heals. In essence, we create a fracture and stabilize the bone in a new position. By rotating the tibial plateau and “leveling” it, the goal is to prevent the femur from sliding down the slope of the tibia and helping to stabilize the knee.
Despite the perceived invasiveness of this procedure, dogs are generally comfortable enough to begin weight bearing on the limb within days of surgery. This rapid return to function/comfort is one of the reasons we prefer the TPLO over the lateral suture technique. A recent study found that even small breed dogs had a more rapid return to weight bearing with a higher level of function with TPLO over a less invasive extracapsular repair technique (lateral imbrication, not a lateral suture).
For the first 8 weeks after surgery, we are completely relying on the implants (plate and screws) to stabilize the surgery site. Once the bone has healed, the plate and screws are no longer necessary, though in most cases implants are left in place unless there is a problem such as infection or irritation. Approximately 3% of patients who have a TPLO procedure will need to have the plate removed.
For dogs under 30 pounds, the lateral suture can be a very effective technique for returning your pet to a high level of activity. However, research is also published now supporting the use of TPLO in small breed dogs and some surgeons may prefer this technique over the lateral extracapsular suture, even in this subset of patients. In medium and large breed dogs (>30 pounds), more and more evidence-based literature shows improved outcomes with TPLO over other commonly performed procedures.
With the TPLO procedure, there is a reported 90-95% good to excellent outcome. An excellent outcome is one where your pet can run, jump and play and you will not notice your pet has ever had a problem. With a good outcome, after heavy activity, your pet may have a transient period of being sore and may need a short course of anti-inflammatories. For one reason or another, 5-10% of patients will not return to a level of function that we hope for. It is important to note that even if your pet suffers a complication, such as an infection or a meniscal injury, they can still have a good to an excellent long-term outcome – there just may be some hiccups along the way.
To see more information and different articles where we have pulled a lot of our information, visit our Literature page.
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