High Tibial Osteotomy

High tibial osteotomy is a surgical procedure in which the bone at the upper end of the tibia (shin bone) is cut and realigned. It is usually performed in arthritic conditions affecting only one side of your knee and the aim is to take pressure off the damaged area and shift it to the other side of your knee with healthy cartilage. During the surgery, your surgeon will remove or add a wedge of bone either below or above the knee joint depending on the site of arthritic damage.

High tibial osteotomy is commonly used for patients with osteoarthritis that is isolated to a single compartment (unicompartmental osteoarthritis). It is also performed for treating a variety of knee conditions such as gonarthrosis with varus or valgus malalignment, osteochondritis dissecans, osteonecrosis, posterolateral instability, and chondral resurfacing.

Two main types of osteotomies used in the treatment of knee osteoarthritis are closed wedge osteotomy and open wedge osteotomy.

In an opening wedge osteotomy an incision is made in the tibia and a wedge shaped bone is removed and the bone graft is added to hold the wedge open. In a closing wedge osteotomy, the surgeon cuts though the tibia and removes a wedge of bone and the open edges are brought together. Both the techniques require bone fixation using plate and screws.

Closed wedge osteotomy may result in instability of the osteotomy, peroneal nerve injuries and failure of correction. These risks are eliminated with open wedge osteotomy.

After general anaesthesia is administered, your surgeon will map out the exact size of the bone wedge to be removed, using an X-ray, CT scan, or 3D computer modelling. A four- to five-inch cut is made down in front of the knee, starting below the kneecap and running below the top of the shinbone. Guide wires are drilled from the lateral side to the top of the shin bone. A conventional oscillating saw is run along the guide wires and the bone wedge underneath the outside of the knee, below the healthy cartilage is removed. The cartilage covering the top of the outside of the shinbone is left intact. Then the top of the shinbone is reduced and fastened with surgical staples or screws. After the procedure is completed, the surgical site is then sutured usually with absorbable sutures and closed in layers.

Complications following high tibial osteotomy may include infection, skin necrosis, non-union (failure of the bones to heal), nerve injury, blood vessel injury, failure to correct the varus deformity, compartment syndrome and deep vein thrombosis or blood clots.