Knee realignment osteotomy for axial correction in osteoarthritis and high-tension osteotomy (HTO)

The most common misalignment of the leg axis is what is known as bowlegs. Bowlegs are caused by a misalignment of the tibia. Degenerative changes in the cartilage on the inner side of the knee joint or in the medial meniscus are also possible. Patients with bowlegs typically experience pain on the inner side of the knee joint. With knock-knees, on the other hand, the outer joint area is overloaded.

In addition to bowlegs and knock-knees, there are other misalignments of the bones in the thigh and lower leg (torsional misalignments). Over time, these lead to pain and wear and tear of the articular cartilage.

A misalignment of the leg axis usually does not become noticeable until adulthood. The doctor will consider leg axis correction if the pain does not improve despite conservative treatment.

Conservative treatment includes:

• Joint-friendly sports (cycling, swimming)
• Physical therapy
• Shoe inserts or axis-modulating orthoses: These provide partial relief to the inner or outer part of the knee joint. However, they are usually tolerated only for a limited time because they are uncomfortable to wear.

Patients up to age 60 whose leg alignment shows a significant deviation benefit from leg alignment correction.

Untreated bowlegs or knock-knees can lead to osteoarthritis in the long term @ TarikVision / AdobeStock

During the initial examination, the doctor determines the type and degree of the misalignment in order to select the best surgical method. A full-leg X-ray (X-ray of the entire leg) plays a crucial role here.

During leg alignment correction, the surgeon cuts the bone and then fixes it in place with a plate. This allows the bone to heal back together in the correct position.

The method used and the location where the doctor cuts the bone depend on the type of misalignment:

• In the case of bowlegs, the misalignment is in the tibia. Therefore, the doctor cuts the bone about 4 cm below the tibial tuberosity. He spreads the bone apart by a few millimeters. The surgery is supported by computer-assisted planning. The doctor then stabilizes the bone with a titanium plate and screws.
• The procedure is similar for bowlegs. However, in this case, the doctor does not need to spread the bone apart but must remove a wedge of bone. Rehabilitation takes a little longer when correcting bowlegs.
• If there is also a misalignment in the thigh bone, the surgery is performed at the corresponding site.
• In cases of combined deformities, a combined correction of the thighbone and shinbone may be necessary.

The patient can be discharged from the hospital after about three to five days. As a rule, the patient uses forearm crutches for six weeks. Throughout this period, targeted physical therapy helps maintain mobility.

The duration of rehabilitation varies from patient to patient. However, patients are usually able to walk short distances without crutches no later than six weeks after surgery. To regain full mobility, patients should attend physical therapy regularly for about three months.

About 12 to 18 months after surgery, the doctor removes the titanium plates. If necessary, the surgeon also performs an arthroscopy to examine the cartilage. If needed, the surgeon treats any areas of cartilage that have not fully healed. 

During the healing period, the patient should attend regular follow-up appointments. Over time, the leg will regain its full weight-bearing capacity. Those with a job that does not involve physical strain can return to work soon after surgery. For jobs involving physical strain, the patient returns to work after about 12 weeks.

As with any surgery, there is a risk of infection or thrombosis following leg alignment correction. In very rare cases, damage to blood vessels and nerves may occur. Additionally, there is a risk of improper bone healing, such as when the fracture gap does not close completely (pseudoarthrosis).

Leg alignment correction is not recommended for heavy smokers or patients who are significantly overweight. 

In general, the procedure is very safe, and complications are rare.

Statistics show that people who have undergone leg alignment correction will still require joint replacement (joint prosthesis) in the long term. However, the procedure can delay this need by about 10 years.

HTO is a surgical procedure performed on the tibia to treat leg misalignments such as bowlegs, knock-knees, genu varum, or genu valgum by performing a valgus correction of the leg axis.

As part of the diagnostic process, supplemented by MRI and arthroscopy, the extent of the axial deviation is precisely determined to establish the indication for a surgical realignment osteotomy of the knee. In this procedure, the tibial tuberosity on the inner side of the knee joint is almost completely severed via an incision on the inner side—often using the open-wedge technique—and stabilized with a plate and screws.

The realignment osteotomy corrects abnormal loading of the knee joint, relieves pressure on the articular surface and the cartilage, and can significantly delay the onset of osteoarthritis in the knee joint as well as cartilage wear and damage.

Following the hospital stay, structured postoperative care is provided, including partial weight-bearing, forearm crutches, physical therapy, physical therapy mobilization exercises, thrombosis prophylaxis, and gradual weight-bearing on the operated leg to improve the mobility and function of the knee joint.

As one of the joint-preserving surgical procedures, this type of realignment osteotomy can delay the need for a later knee replacement or endoprosthesis, particularly in cases of leg deformities resulting from accidents or congenital axial deviations.