High Tibial Osteotomy (HTO) is a joint-preserving surgical procedure used to correct abnormal alignment of the knee and reduce excessive loading on a damaged compartment. It is particularly useful in carefully selected patients with varus knee alignment and medial compartment knee osteoarthritis. Unlike knee replacement, HTO preserves the patient's natural knee joint and aims to redistribute the load across the knee.
For active patients who want to continue activities that place higher demands on the knee, high tibial osteotomy can be an important alternative to joint replacement. The decision, however, depends on age, activity level, alignment, cartilage condition, ligament stability, range of motion and the condition of the other knee compartments.
What is High Tibial Osteotomy?
High Tibial Osteotomy is an operation in which the upper part of the tibia is carefully cut and realigned to correct a deformity around the knee.
In a varus knee, the mechanical axis passes more medially through the knee, increasing the load transmitted through the medial compartment. Over time, this can contribute to progression of medial compartment osteoarthritis.
HTO changes the alignment of the lower limb so that the load is redistributed away from the diseased medial compartment toward the relatively preserved part of the knee.
The principle of osteotomy is therefore simple:
Correct the alignment → redistribute the load → reduce medial compartment overload → preserve the native knee.
The UK Knee Osteotomy Consensus Group recognizes symptomatic unicompartmental osteoarthritis with malalignment as an indication for osteotomy, while also recognizing indications involving meniscal deficiency, cartilage repair and ligamentous instability.
Who is a Good Candidate for High Tibial Osteotomy?
Patient selection is one of the most important factors determining the success of high tibial osteotomy.
HTO is generally considered in patients who have:
Symptomatic medial compartment knee osteoarthritis
Varus alignment of the lower limb
Medial compartment overload
Relatively preserved lateral compartment
Acceptable patellofemoral status
Reasonably preserved knee movement
A desire to remain physically active
No major contraindication to osteotomy
The ideal patient is not defined by age alone. A younger, active patient with symptomatic medial compartment disease may benefit particularly from a joint-preserving procedure.
Modern consensus also recognizes that osteotomy can be considered in selected patients with ligament instability, meniscal deficiency or cartilage lesions, when appropriate mechanical malalignment is present.
When is HTO Recommended for Knee Arthritis?
The most common indication is:
Medial compartment knee osteoarthritis + varus malalignment
When the medial compartment is overloaded because of varus alignment, correcting the alignment can reduce the forces acting on the diseased compartment.
However, not every patient with medial knee arthritis and varus alignment requires HTO.
The surgeon must assess:
Where the deformity originates
Severity of arthritis
Lateral compartment cartilage
Meniscal status
Patellofemoral joint
ACL/PCL and collateral ligament status
Knee range of motion
Tibial slope
Patient age and activity level
A standing long-leg alignment radiograph is particularly important for understanding the mechanical axis and planning the correction.
High Tibial Osteotomy for Varus Knee
A varus knee causes the mechanical axis to pass toward the medial side of the knee.
This increases medial compartment loading.
HTO corrects this alignment by creating a controlled angular correction around the proximal tibia.
Depending on the deformity and surgical plan, the correction can be achieved using:
Medial opening-wedge HTO
Lateral closing-wedge HTO
Biplanar or modified osteotomy techniques
Other techniques selected according to the location and nature of the deformity
The choice of technique is individualized rather than being determined simply by the degree of varus.
What Tests Are Needed Before High Tibial Osteotomy?
A detailed clinical and radiological assessment is essential.
Weight-Bearing X-rays
These typically include:
Standing AP knee radiograph
Lateral knee radiograph
Skyline/merchant view for the patellofemoral joint
Full-length standing hip-to-ankle alignment radiograph
The alignment film helps determine the mechanical axis and identify whether the deformity is predominantly tibial, femoral or combined.
Valgus Stress X-Ray
A valgus stress radiograph can be useful in selected patients to assess:
Correctability of varus deformity
Lateral compartment preservation
Ligamentous contribution to the deformity
This can help differentiate patients who may be better suited for an osteotomy from those who may require another treatment strategy.
What About Bone-on-Bone Medial Arthritis?
This is an important question when considering high tibial osteotomy.
Traditionally, advanced or bone-on-bone medial compartment osteoarthritis was considered an unfavorable indication for HTO. However, contemporary evidence suggests that advanced medial compartment OA is not automatically an absolute contraindication in carefully selected patients. Recent systematic-review evidence has reported good survivorship and clinical outcomes in selected patients with advanced medial OA.
The overall condition of the knee matters more than the X-ray alone.
A patient with:
Young/active profile + correctable varus + preserved lateral compartment + acceptable ligaments
may still be considered for HTO despite advanced medial disease.
Conversely, extensive disease involving multiple compartments generally makes a joint-preserving osteotomy less appropriate.
High Tibial Osteotomy and ACL Deficiency
HTO also has an important role in selected ACL-deficient varus knees.
When ACL deficiency is associated with varus alignment, simply reconstructing the ACL may not address the abnormal mechanical environment.
In selected patients, HTO can:
Correct varus alignment
Reduce medial compartment overload
Modify posterior tibial slope when indicated
Reduce anterior tibial translation
Provide a more favorable environment for ACL reconstruction
The UK Knee Osteotomy Consensus Group recognizes addressing instability, with or without ligament reconstruction, as an indication for osteotomy in appropriately selected malaligned knees.
Therefore, in a patient with varus + ACL deficiency + symptomatic instability, the treatment plan may involve HTO alone or HTO combined with ACL reconstruction depending on the individual clinical situation.
HTO or Knee Replacement: Which is Better?
HTO and knee replacement are not interchangeable procedures.
HTO
HTO is a joint-preserving procedure.
It is particularly attractive for patients who:
Are physically active
Have predominantly unicompartmental disease
Have correctable malalignment
Want to preserve their native knee
May wish to continue higher-impact activities
Knee Replacement
Knee replacement removes and replaces the damaged joint surfaces.
Depending on the disease pattern, options include:
Unicompartmental knee arthroplasty
Total knee replacement
The choice between HTO and arthroplasty depends on the patient's age, symptoms, activity, alignment, cartilage status, ligament function and expectations.
The modern osteotomy literature recognizes UKA as an alternative to HTO in appropriately selected patients, with the choice individualized according to patient and disease characteristics.
For general information about treatment options for knee osteoarthritis, you can also read the American Academy of Orthopaedic Surgeons' patient information. AAOS – Knee Osteoarthritis
What Happens During HTO Surgery?
During high tibial osteotomy, the surgeon first confirms the planned correction and surgical landmarks.
The operation generally involves:
Positioning the patient and obtaining appropriate fluoroscopic views
Exposing the proximal tibia
Planning and marking the osteotomy
Performing the controlled bone cuts
Creating the planned angular correction
Confirming alignment with fluoroscopy
Fixing the osteotomy using an appropriate plate and screws
Confirming final alignment and implant position
Modern techniques may use a biplanar osteotomy, which can improve stability and bone contact and may help address issues such as patellar height depending on the specific technique.
The exact technique is selected according to the patient's deformity, bone morphology and surgical objectives.
Recovery After High Tibial Osteotomy
Recovery following HTO surgery varies according to the type of osteotomy, fixation method, bone quality, correction size and individual healing.
Rehabilitation commonly includes:
Pain and swelling control
Early knee range-of-motion exercises
Quadriceps activation
Protected weight-bearing initially when required
Progressive strengthening
Gradual improvement in walking
Progressive return to functional activities
Bone healing must be monitored clinically and radiologically before progressing weight-bearing according to the surgeon's protocol.
Return to sports is individualized and should occur only after adequate bone healing, strength recovery, movement restoration and functional rehabilitation.
What Are the Risks of High Tibial Osteotomy?
As with any major orthopaedic procedure, HTO has potential complications.
These may include:
Delayed union or non-union
Loss of correction
Hinge fracture
Infection
Neurovascular injury
Changes in tibial slope
Patellar height changes
Persistent pain
Hardware-related symptoms
Progression of osteoarthritis
Careful patient selection, accurate preoperative planning and appropriate surgical technique are important for reducing these risks.
Is High Tibial Osteotomy Right for You?
The most important point is that HTO is not simply a treatment for a crooked knee.
It is a joint-preservation procedure designed to correct a specific mechanical problem.
A patient with medial compartment arthritis should therefore be assessed for:
Alignment + cartilage + meniscus + ligaments + range of motion + patellofemoral joint + activity requirements.
If these factors are favorable, high tibial osteotomy can provide pain relief while preserving the patient's native knee and potentially delaying the need for knee replacement.
If you have persistent medial-sided knee pain, varus deformity or difficulty with activities because of knee arthritis, a specialist assessment can determine whether HTO, cartilage/meniscal preservation, unicompartmental knee replacement or total knee replacement is the most appropriate option.
For information about your orthopaedic services, you can visit Dr. Manohar's Orthopaedic & Sports Injury Clinic.
Frequently Asked Questions
Is high tibial osteotomy better than knee replacement?
Neither procedure is universally better. HTO preserves the native knee and may be particularly suitable for younger, active patients with appropriate unicompartmental disease and malalignment. Knee replacement may be more appropriate when arthritis is advanced or involves multiple compartments.
Can HTO be done for bone-on-bone arthritis?
Yes, in selected patients. Bone-on-bone medial compartment arthritis is not automatically an absolute contraindication. Patient selection and the condition of the other compartments are critical.
Can HTO be performed in an ACL-deficient knee?
Yes. In selected patients with varus malalignment and ACL deficiency, HTO can be performed alone or combined with ACL reconstruction, depending on the clinical situation.
How long does HTO recovery take?
Recovery varies considerably. Bone healing, correction size, fixation and rehabilitation all influence the timeline. Return to higher-level sports generally requires a longer rehabilitation period than return to routine daily activities.
Does HTO prevent knee replacement permanently?
HTO is intended to preserve the knee and delay arthroplasty, but it cannot guarantee that a knee replacement will never be required. Some patients may eventually develop progression of arthritis and require knee replacement.
Key Takeaway
High Tibial Osteotomy is a joint-preserving treatment for carefully selected patients with knee pain, varus malalignment and predominantly medial compartment disease. By correcting the mechanical axis and redistributing load, HTO can reduce medial compartment overload while preserving the patient's natural knee.
The best results come from accurate deformity analysis, appropriate patient selection, precise correction and structured rehabilitation.
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