Overview
High tibial osteotomy (HTO) is a well-established procedure for unicompartmental osteoarthritis of the knee with a corresponding varus or valgus deformity. Its biomechanical rationale is to unload the diseased compartment by correcting malalignment and redistributing stress. Most reports show about 80% satisfactory results at 5 years and 60% at 10 years, and results deteriorate over time. HTO remains useful in properly selected patients. (Campbell)
The most common deformity is varus, which concentrates load medially. Four basic types are used: medial opening wedge, lateral closing wedge, dome, and medial opening hemicallotasis. The lateral closing wedge (Coventry) has the longest track record. (Campbell)
Indications
Indications (Campbell Box 10.4)
Pain and disability from osteoarthritis that significantly interfere with high-demand work or recreation.
Weight-bearing radiographs showing degenerative arthritis confined to one compartment, with a corresponding varus or valgus deformity.
Ability to use crutches or a walker, with enough muscle strength and motivation for rehabilitation.
Symptoms concordant with radiographic findings (for example isolated medial pain in a varus knee).
Contraindications
Narrowing of the lateral compartment cartilage space.
Lateral tibial subluxation of more than 1 cm.
Medial tibial bone loss of more than 2 or 3 mm.
Flexion contracture over 15 degrees, or knee flexion under 90 degrees.
More than 20 degrees of correction needed.
Inflammatory arthritis. Significant peripheral vascular disease.
Factors associated with a good result: age under 60, purely unicompartmental disease, ligamentous stability and a preoperative arc of motion of at least 90 degrees. Survivorship was 44% at 20 years after lateral closing wedge HTO, better with age under 55, BMI under 30 and a preoperative WOMAC score above 45. (Campbell)
Choice of technique. There is no distinct advantage of opening versus closing wedge. A randomized trial found no difference in clinical outcome or alignment. The opening wedge group had more complications and the closing wedge group more early conversion to TKA. Medial opening wedge is easier to expose and allows correction to be titrated. It is indicated particularly for medial collateral laxity, combined ACL deficiency or chronic grade III posterolateral corner instability with varus. A valgus deformity over 12 degrees, or postoperative joint line tilt over 10 degrees, favors a supracondylar femoral osteotomy instead. (Campbell)
Planning the Correction (Campbell)
Normal tibiofemoral alignment on weight-bearing radiographs is 5 to 8 degrees of valgus. Calculate the correction needed to reach the normal angle and add 3 to 5 degrees of overcorrection, to about 10 degrees of valgus.
With a varus deformity, the only limit on correction is the size of wedge that can be taken proximal to the patellar tendon.
Methods to size the wedge:
Bauer: 1 degree of correction per 1 mm of wedge base (valid only if the tibia is 57 mm wide).
Full-length standing AP radiographs, cutting the wedge so the mechanical axis (femoral head center to ankle center) passes through the desired point.
Campbell's preference: exact measurement from a right-triangle drawing, or W = tibial width × 0.02 × angle.
Failure risk increases if alignment is not overcorrected to at least 8 degrees of valgus and if the patient is more than 30% over ideal body weight.
Same-session arthroscopy helps confirm the indication and adjust the correction to cartilage status. (Campbell)
Technique 10.10: Lateral Closing Wedge Osteotomy with a Jig (Modified Coventry; Hofmann, Wyatt and Beck) (Campbell)
With the patient supine, place a sandbag under the ipsilateral hip. Tape a sandbag to the table to hold 90 degrees of knee flexion, which carries the popliteal vessels and peroneal nerve posteriorly and relaxes the iliotibial band.
Prepare the limb from the anterior superior iliac spine to the ankle and apply a thigh tourniquet.
Make an inverted L-shaped incision: the transverse limb along the lateral joint line to the fibular head, the vertical limb in the tibial midline for 10 cm distally.
Divide the proximal tibiofibular capsule with a sharp 3/4-inch curved osteotome. Protect the neurovascular structures with a blunt Hohmann retractor throughout.
Mark the joint line with Keith needles or small Kirschner wires and place the transverse osteotomy jig with its top touching them.
Stabilize the jig with a 3.2-mm drill hole to the third mark and fill it with a smooth pin.
Flex and extend the guide to match the posterior slope and confirm plate position by placing the plate over the pin. Drill a second hole and place a second smooth pin.
Drill across the tibia through the central hole of the guide and measure tibial width with a depth gauge.
Make the transverse cut with a calibrated saw, leaving a 10-mm bridge of medial cortex intact.
Replace the transverse jig with the slotted oblique jig (slots in 2-mm increments for 6 to 20 degrees of correction). Make the oblique cut and remove the jig, leaving the pins.
Remove the wedge and make sure no bone is left in the site.
Apply a buttress (L) plate over the two smooth pins. Replace one pin with a 6.5-mm cancellous screw, using the other pin as a parallel alignment marker, then replace the second pin with a cancellous screw. Typical screw length is 60–70 mm in men and 50–60 mm in women (50 mm in very young patients for easier removal). Do not tighten until the distal cortical screws are in.
Using the distal plate holes as reference, drill a single-cortex 3.2-mm hole in line with and distal to the plate. Insert the curved pin of the compression clamp there and the straight pin in the most distal plate hole. Compress slowly. This often takes 5 minutes, allowing plastic deformation at the incomplete osteotomy. If compression is difficult, check that the proximal tibiofibular joint is fully disrupted and no wedge remains.
When closed, check overall alignment with a long alignment rod or electrocautery cord. From hip center to ankle center, the line should pass through the lateral compartment of the knee. Confirm with radiographs or fluoroscopy.
Insert a self-tapping cortical screw through the central round hole, then remove the clamp and insert a cortical screw in the most distal hole. Tighten the proximal cancellous screws. Avoid severe torque, particularly on cortical screws. Do not use a power driver for final tightening.
Release the tourniquet and obtain hemostasis. Irrigate, insert a small suction drain, loosely close the anterior compartment fascia and iliotibial band, close the subcutaneous layer with absorbable sutures and the skin with staples. Apply a large compressive Jones dressing.
Surgical tips (Campbell)
Leave a thin posteromedial lip of bone on the proximal fragment so it overrides the distal fragment when the wedge closes.
If the deformity is undercorrected, curette cancellous bone just medial to the lateral edge rather than removing more cortex.
Anterior translation of the distal fragment greater than 1.5 cm is associated with better functional scores.
The proximal tibiofibular joint must be disrupted, either by removing the inferomedial fibular head or carefully disrupting the syndesmosis. Protect the peroneal nerve.
Rigid internal fixation avoids cast immobilization.
Navigation improves alignment accuracy but does not necessarily improve clinical results.
Postoperative Care (Campbell)
Continuous passive motion starts in the recovery room, 0 to 30 degrees, progressing 10 degrees a day.
Ambulation on day 2 with crutches and 50% weight bearing for the first 6 weeks.
Muscle strengthening and active ROM from day 2.
Full weight bearing after 6 weeks.
Complications
Recurrent deformity. Loss of correction in 5%–30%. Overcorrection beyond the normal 5 degrees of anatomic valgus appeared to lower this in one study. (Campbell)
Systematic review figures. Intraoperative complications 5.5% and postoperative 6.9%. Lateral hinge fracture 9.1% and peroneal nerve injury 3.2%. Reoperation 15.5%, most commonly implant removal (10.0%). Gap height is the only predictor of lateral hinge fracture after medial opening wedge HTO. (Campbell)
Opening wedge. Lateral hinge fracture extending into the lateral plateau (15%–18%) and leg-length discrepancy. (Campbell)
Peroneal nerve palsy. Most often related to fibular osteotomy, because the nerve wraps around the fibular neck. (Campbell)
Popliteal artery injury. Rare but devastating. At 90 degrees of flexion the saw blade averaged only 10.6 mm from the artery in a cadaver study, so keep a wide malleable retractor between the tibia and the artery, especially with an oscillating saw. (Campbell)
Patella baja. Caused by patellar tendon shortening, new bone at the tendon insertion and fibrosis. It does not affect the success of the osteotomy but makes later TKA harder. (Campbell)
Others. Nonunion, infection, stiffness or instability, intraarticular fracture, DVT, compartment syndrome and osteonecrosis of the proximal fragment. (Campbell)
References
Lamplot JD. Knee preservation surgery. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 10, Proximal tibial osteotomy, Technique 10.10.