High Tibial Osteotomy (HTO) – Procedure, Recovery & Outcomes

What is High Tibial Osteotomy?

High tibial osteotomy (HTO) is a surgical procedure in which the upper part of the shinbone (tibia) is carefully cut and repositioned to correct a misalignment of the leg axis. The most common deformity addressed is a bow-legged alignment (varus deformity), which places excessive pressure on the inner (medial) compartment of the knee joint.

By realigning the mechanical axis of the leg, the load is redistributed more evenly across the knee joint, reducing pain and slowing the progression of cartilage damage. HTO is primarily recommended for younger, active patients who have medial knee osteoarthritis (gonarthrosis) and wish to delay or avoid total knee replacement surgery.

Indications

High tibial osteotomy is typically indicated in the following situations:

• Medial knee osteoarthritis combined with varus (bow-leg) malalignment
• Patients under 60 years of age with adequate bone quality and remaining cartilage
• Physically active patients who want to preserve joint function and delay knee replacement
• Knee instability due to ligament injuries in combination with leg axis deformity
• Osteochondral defects requiring load redistribution prior to cartilage repair surgery

Surgical Techniques

There are two main techniques used in high tibial osteotomy:

1. Opening Wedge Osteotomy (Open-Wedge HTO)

In this approach, a cut is made on the inner (medial) side of the tibia, and the bone is gently opened like a wedge. The gap is filled with bone graft or a bone substitute material, and the corrected position is secured with a special locking plate and screws. This is currently the most widely used technique due to its precision and versatility.

2. Closing Wedge Osteotomy (Closed-Wedge HTO)

In this technique, a wedge of bone is removed from the outer (lateral) side of the tibia, and the two bone surfaces are then compressed together. This method is performed less frequently today, as it carries a higher risk of damage to the peroneal nerve and requires more complex surgical planning.

Preoperative Planning

Careful preoperative assessment is essential for a successful outcome. Typical evaluations include:

• Full-leg X-ray (standing): To measure the mechanical axis of the lower limb and the degree of malalignment
• MRI of the knee: To assess cartilage damage, meniscal integrity, and ligament condition
• CT scan (optional): For detailed 3D planning of the correction
• General preoperative workup including blood tests, ECG, and anesthesia consultation

Surgical Procedure

The operation is typically performed under spinal or general anesthesia with the patient lying on their back. Through a small incision on the medial or lateral side of the tibia (depending on the technique), the bone is cut using specialized surgical saws and instruments, then repositioned at the planned correction angle. A locking plate with screws is used to stabilize the osteotomy. The procedure generally takes between 60 and 90 minutes.

Postoperative Care and Rehabilitation

Rehabilitation plays a crucial role in recovery and long-term success:

• Partial weight-bearing: For the first 6 weeks after surgery, patients typically use crutches and bear only partial weight on the operated leg.
• Physiotherapy: Early mobilization exercises, quadriceps strengthening, and coordination training begin shortly after the operation.
• Full weight-bearing: Depending on bone healing, full weight-bearing is usually permitted after 8 to 12 weeks.
• Return to sport: Light physical activity is generally possible after 4 to 6 months, with higher-impact sports requiring additional recovery time.
• Hardware removal: The stabilizing plate can optionally be removed in a minor procedure approximately 12 to 18 months postoperatively.

Risks and Possible Complications

As with any surgical procedure, HTO carries certain risks that should be discussed with the treating surgeon:

• Wound infection or bone infection (osteitis)
• Delayed bone healing or non-union (pseudarthrosis)
• Nerve damage, particularly to the peroneal nerve
• Deep vein thrombosis or pulmonary embolism
• Implant failure or plate breakage
• Undercorrection or overcorrection of the leg axis
• Avascular necrosis (bone tissue loss due to disrupted blood supply)

Outcomes and Prognosis

When patient selection and surgical technique are appropriate, high tibial osteotomy delivers excellent long-term results. Studies indicate that in over 80% of suitable patients, knee replacement surgery is not required even 10 years after the procedure. Most patients experience significant pain relief, improved knee function, and an enhanced quality of life, often returning to recreational and even competitive sports activities.

References

1. Lobenhoffer, P., Agneskirchner, J.D. (2003): Improvements in surgical technique of valgus high tibial osteotomy. Knee Surgery, Sports Traumatology, Arthroscopy, 11(3), 132–138.
2. Brouwer, R.W. et al. (2014): Osteotomy for treating knee osteoarthritis. Cochrane Database of Systematic Reviews, Issue 12. DOI: 10.1002/14651858.CD004019.pub4.
3. Felson, D.T. (2006): Osteoarthritis of the knee. New England Journal of Medicine, 354(8), 841–848.