Medial Opening Wedge High Tibial Osteotomy

Overview

Medial opening wedge high tibial osteotomy unloads the medial tibiofemoral compartment by correcting varus malalignment. It can treat symptomatic medial-compartment overload and can protect selected cartilage-restoration or meniscal-replacement procedures. The operation changes load distribution; it does not replace damaged cartilage (Campbell, Chapter 10).

The central technical goals are correction to the planned mechanical axis, preservation of the lateral hinge, protection of posterior neurovascular structures and stable fixation without an unintended increase in posterior tibial slope. This guide follows Campbell Technique 10.11, a plate-fixed medial opening wedge proximal tibial osteotomy.

Indications and Contraindications

• Typical indication: symptomatic medial-sided knee pain with chondrosis or osteoarthritis and corresponding varus malalignment, after assessment of other treatment options.

• Reconstructive adjunct: unloading a medial compartment during meniscal allograft transplantation or cartilage restoration.

• Symptoms should agree with the weight-bearing radiographic findings. The patient needs the strength, motivation and ability to use walking aids during rehabilitation.

• Box 10.4 lists unfavorable findings for osteotomy in an arthritic knee: lateral compartment joint-space narrowing, inflammatory arthritis, significant peripheral vascular disease, marked tibial subluxation or bone loss, flexion contracture over 15 degrees, flexion below 90 degrees and a need for very large correction.

• Associated ligament laxity must be assessed. A varus knee with posterolateral instability may need a staged or combined realignment and stabilization plan rather than isolated ligament reconstruction.

(Campbell, Chapter 10.)

Preoperative Planning

Do not use a fixed millimeter-to-degree conversion without considering tibial width and the individual template. Large corrections may require a two-level osteotomy to avoid excessive single-level correction and joint-line obliquity (Campbell, Chapter 10).

Positioning and Setup

1. Position supine on a radiolucent table with a hip bump to orient the knee perpendicular to the table.

2. Ensure access for anteroposterior and lateral fluoroscopic views and for intraoperative mechanical-axis assessment.

3. Prepare a saw, osteotomes, a controlled spreading device, alignment rod, structural and cancellous graft options, and a medial locking plate.

4. Have a suitable posterior retractor available. Flexion of the knee alone does not provide adequate protection for posterior cutting.

(Campbell, Chapter 10, Technique 10.11 and general HTO complications.)

Surgical Technique

Medial Exposure and Protection

1. Make a medial proximal tibial incision from the joint line distally, between the tibial tubercle and posterior tibial border. The source describes an incision of approximately 8 cm.

2. Open the sartorial fascia, mobilize the pes anserine tendons posteriorly and identify the patellar tendon.

3. Develop the plane behind the superficial MCL and carefully elevate the muscle from the posterior tibia.

4. Place a substantial malleable or radiolucent retractor immediately behind the tibia to protect the neurovascular structures throughout the osteotomy.

(Campbell, Chapter 10, Technique 10.11.)

Osteotomy and Lateral Hinge

1. Create the sagittal countercut behind the proximal tibial tubercle, protecting the tendon and retaining adequate anterior bone. Technique 10.11 describes a 2–2.5-cm cut with at least 2–3 mm of bone anterior to it.

2. Place two parallel guidewires just distal to the medial metaphyseal flare, directed toward the proximal half of the fibular head.

3. Confirm the planned cut fluoroscopically and retain at least 1.5 cm between the osteotomy and articular surface in the described technique.

4. Complete the planned medial osteotomy through the anterior and posterior cortices under protection. Preserve a lateral hinge of at least 1 cm.

5. Make sure that the anterior and posterior cuts are sufficient before attempting distraction. Forceful opening of an incomplete cut increases the risk of hinge fracture.

(Campbell, Chapter 10, Technique 10.11.)

Controlled Correction

1. Open the osteotomy gradually with stacked osteotomes.

2. Use a spreading device to advance slowly to the preoperatively templated opening. Allow time for the bone to deform rather than forcing an abrupt correction.

3. Check the mechanical axis with an alignment rod and compare the correction with the plan.

4. Check sagittal alignment and posterior tibial slope. Avoid an unintended slope increase, particularly in a knee with ACL deficiency or associated medial laxity.

5. Inspect for propagation into the lateral hinge or tibial plateau. If a fracture has occurred, reassess stability and the fixation plan before proceeding.

(Campbell, Chapter 10.)

Grafting and Fixation

1. Maintain the correction with spreaders while preparing the osteotomy gap.

2. Place the selected structural graft before removing the spreaders. Campbell describes appropriately sized iliac crest, femoral neck or other structural wedges, with cancellous material filling the remainder as appropriate.

3. Apply the medial locking plate and verify its position on both anteroposterior and lateral fluoroscopy before completing screw placement.

4. Fix the proximal and distal segments securely while maintaining the achieved correction. Keep proximal screws out of the joint and intercondylar notch.

5. Repeat fluoroscopic checks of the axis, slope, hinge and implant position after fixation.

(Campbell, Chapter 10, Technique 10.11.)

Pearls and Pitfalls

• Template the whole limb: a painful varus knee does not automatically mean the entire deformity should be corrected in the proximal tibia.

• Protect the posterior structures directly: even with the knee flexed, the popliteal artery can lie close to the saw path.

• Open slowly: larger opening gaps increase the risk of lateral hinge fracture.

• Monitor two planes: a satisfactory coronal correction can coexist with an undesirable slope change.

• Maintain correction during fixation: graft insertion and plate application must not allow loss of the planned axis.

• Account for leg length: an opening wedge may be less suitable when the involved leg is already longer.

(Campbell, Chapter 10.)

Postoperative Considerations

Aftercare must reflect the fixation construct, hinge integrity and any accompanying ligament, meniscal or cartilage procedure. Campbell emphasizes rigid fixation and the patient's ability to comply with rehabilitation. The immediate-loading schedules described for circular or dynamic external fixation are specific to those methods and should not be transferred to a plate-fixed opening wedge osteotomy (Campbell, Chapter 10).

Complications and Outcomes

• Lateral hinge fracture or extension into the tibial plateau can compromise the correction and stability.

• Delayed union, nonunion, loss of correction or recurrent varus can cause persistent pain and failure.

• Neurovascular injury, infection, venous thromboembolism, compartment syndrome and knee stiffness are important risks.

• Patellar height, posterior tibial slope and leg length may change, affecting later function or arthroplasty.

• Osteotomy may delay arthroplasty in selected patients, but results deteriorate with time. Campbell reports no clear clinical superiority of opening versus closing wedge methods in the cited randomized comparison; patient selection and achieved alignment remain central.

(Campbell, Chapter 10.)

References

1. Lamplot JD. Knee preservation surgery. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Elsevier; 2026. Chapter 10, proximal tibial osteotomy and patient selection, pp. 499–500; medial opening wedge osteotomy, pp. 504–508, Technique 10.11.