Proximal Tibial Osteotomy
What is a Proximal Tibial Osteotomy?
Proximal tibial osteotomies, also known as high tibial osteotomies, involve correcting bow-leggedness. This involves creating a surgical fracture on the medial (inside) aspect of the tibia (shin bone) and wedging it open to allow the leg alignment to swing over. A plate and screws are then used to hold it in place and bone graft is inserted into the opening created. In younger patients (under 50 years old), a proximal tibial osteotomy can allow patients to still participate in high-level activities, such as climbing, hiking, and hunting, without fear of having the metal and plastic from a knee replacement wear out. We certainly do not advocate that patients go back to high-impact activities, such as long distance running, because they run the risk of having their knee wear out sooner.
Why have a Proximal Tibial Osteotomy?
There are 3 main indications for performing proximal tibial osteotomies. The most common is in patients who have developed arthritis on the medial (inside) aspect of their knee, most commonly due to having a previous partial medial meniscectomy, and who are bow-legged and the rest of the knee cartilage is fairly well intact. In these patients, creating a proximal tibial osteotomy and shifting the weight over to the center or slightly lateral (outside) aspect their knee has been found to be very effective in relieving the symptoms of medial compartment arthritis and delaying the need for total knee replacement.
Another common indication for performing a proximal tibial osteotomy is in patients that are bow-legged and in need of a medial meniscus transplant, and/or a medial compartment cartilage resurfacing procedure. It is generally felt that a medial meniscus transplant or cartilage resurfacing procedure is at greater risk of failure if the patient is bow-legged. Thus, a proximal tibial osteotomy either concurrently with or prior to a cartilage resurfacing procedure and/or meniscal transplant is sometimes indicated.
The other most common reason for performing a proximal tibial osteotomy is in patients who have ligament problems. For patients who have a chronic posterolateral corner injury that are bow-legged, the risk of having the graft on the outside of their knee stretch out is very high and it is generally felt that one should have a proximal tibial osteotomy performed prior to the lateral collateral ligament and posterolateral corner reconstruction.
Other indications include patients who have a cruciate ligament reconstruction and who have an increased posterior tilt of their tibia. Most commonly, a tilt backwards of the tibia with an ACL tear causes an ACL graft to have a high risk of failure and an anterior closing wedge osteotomy would help to unload this. This was already discovered by our veterinary colleagues many years ago where they found out that ACL surgeries did not work in dogs because the tibia was tilted so far posterior. Thus, almost all dog “ACL reconstructions” are actually a closing wedge proximal tibial osteotomy, which works quite well in these circumstances. The other indication would be in patients who have a flat tibial slope and concurrent PCL tear that is chronic, especially in those who may have some medial compartment arthritis. Increasing the slope in these patients, by tilting the tibia back, can be very effective at providing stability to PCL-deficient knees. In fact, some patients may find that they have enough stability that they do not need a later PCL reconstruction.
What is the Recovery After Proximal Tibial Osteotomy?
Postoperatively, patients who have a proximal tibial osteotomy usually are partial weightbearing for the first 6 weeks after surgery with a gradual progression of weightbearing during that time. Patients can wean off crutches after 6 weeks when they can walk without a limp at that point in time. In general, the recovery from a proximal tibial osteotomy can be quite rapid at that point in time because one does not have to worry about ligament healing or other issues and working on a progressive quadriceps strengthening program with a stationary bike and elliptical machine can also allow one to get back to activities sooner. Most patients reach their maximal improvement after an osteotomy, assuming that the strength is restored, at about 6 months postoperatively.
How Successful is a Proximal Tibial Osteotomy?
The outcomes of proximal tibial osteotomies in delaying the need for a total knee arthroplasty are approximately 75% to 80% at 10 years, with some studies reporting that 65% of patients up to 20 years have relief of their knee pain.