High Tibial Osteotomy - Indications, Planning, Procedure, and Complications

Introduction

High tibial osteotomy (HTO), first described by Jackson and Waugh in 1961, has gained popularity since 1965 under the direction of Coventry as a treatment option for medial compartment osteoarthritis of the knee with varus deformity. In varus knees (bowlegs), HTO aims to alleviate knee pain by shifting weight-bearing loads to the lateral compartment, which is largely unharmed, and to postpone the need for knee replacement surgery by slowing or halting the degeneration of the medial joint compartment. Although the use of HTO has lately decreased as a result of advancements in knee arthroplasty, it is undeniable that proper patient selection, meticulous surgical planning, and a variety of operative approaches can result in successful treatment outcomes for HTO. There is still debate over HTO's comparative benefits to unicompartmental knee arthroplasty (knee replacement), the choice of opening and closing wedge HTO, graft selection in opening wedge HTO, the form of fixation, and the impact of HTO on following knee arthroplasty.

What Are the Indications and Contraindications for High Tibial Osteotomy?

Indications:

• Osteoarthritis: Advanced medial compartment knee arthritis with excruciating pain and movement restrictions.

• A severe angular deformity increases the risk of unicompartmental osteoarthritis.

Contraindications:

Surgery is not recommended for people who have:

• Inflammatory arthritis.

• People with a BMI of 35 or higher who are obese.

• 15 degrees or more of flexion contracture is present.

• Greater than 90-degree flexion of the knee, patellofemoral arthritis (knee problem).

• Instability of a ligament.

• Varus thrusts (bowing out of the knee during gait) when walking.

What Are the Preoperative Planning Protocols for High Tibial Osteotomy?

• Patient Assessment: Before choosing surgery, the patient's age, profession, degree of exercise, prior knee surgery history, and expectations should be taken into account. For patients who smoke frequently, closed wedge HTO may be more advantageous in lowering the risk of nonunion than open wedge HTO.

• Radiographic Assessment: For preoperative radiographic evaluation, several views should be obtained, including skyline views, tunnel views with the knee in 30° (degree) of flexion, Rosenberg views with the knee in 45° of flexion, lateral views, and bilateral weight-bearing anterior-posterior views in full extension. Using the Insall-Salvati, Blackburne-Peel, or Caton-Deschamps index, patellar height can be determined from the lateral views, and the degree of medial osteoarthritis and bone loss can be assessed from the anterior-posterior views. The simultaneous use of tibial tubercle osteotomy (a surgical procedure to treat kneecaps) and closing or opening HTO may be necessary for a severe patella alta (kneecap abnormality). The alignment of the hip, knee, and ankle joints can be seen on full-length radiographs of the lower extremity, which can be used to evaluate lower limb alignment. An intraosseous lesion, a meniscus rupture (knee tissue injury), a ligamentous lesion, an osteochondral defect (bone defect), osteonecrosis (bone death), or subchondral edema can all be found using magnetic resonance imaging.

• Correction Angle Calculation: In healthy lower extremities, the mechanical axis, or line connecting the points, is 0°, and the centers of the hip, knee, and ankle are all in the same plane. Most studies suggest 8 (degree) to 10° (degree)

• of anatomical valgus or 3 (degree) to 5 (degree) of valgus from the mechanical axis as the optimal post-operative lower limb position. Under-correction and overcorrection both run the risk of causing the varus deformity to reoccur, so care should be taken when planning and executing correction.

What Are the Different Techniques of High Tibial Osteotomy, and How Is It Done?

The purpose of the procedure is to maintain the joint line perpendicular to the mechanical axis of the leg and to relieve the affected joint compartment by adjusting the tibia's (shin bone) misalignment. Opening wedge osteotomy and closing wedge osteotomy are two of the techniques used. Based on the patient's needs, the surgeon chooses the appropriate approach.

• Opening Wedge Osteotomy: In order to remove a small wedge of bone from the upper portion of the tibia or shin bone on the medial or inner side, the surgeon creates a small incision in front of the knee, just below the knee cap. By employing guide wires, the surgeon may precisely measure the size of the bone to be removed. To aid the osteotomy's healing, a wedge of bone is removed using an oscillating saw, and the empty space is replaced with a bone graft. By realigning the knee, the patient's painful symptoms are reduced, and the knee's angle is increased.

• Closing Wedge Osteotomy: When performing a high tibial osteotomy, this method is most frequently employed. A small wedge of bone from the upper section of the tibia's lateral, or outer, side is removed during this treatment by the surgeon through an incision made in front of the knee. To bring the bones together and fill the cavity, this end of the tibia is then lowered. In order to keep the bones together while the osteotomy heals, the surgeon utilizes plates and screws. By performing this treatment, the joint is relieved of some of its weight, and some weight is transferred to the outside portion of the knee, where the cartilage is still in good condition.

What Is the Post-operative Care for High Tibial Osteotomy?

Patients may need to stay in the hospital for two to four days following an osteotomy. A light compressive knee brace or splint may be applied right once following surgery to protect the knee, and painkillers may be administered to lessen any discomfort or swelling. Patients are advised to follow post-operative protocols throughout this period to ensure success.

The use of TED stockings to lower the chance of clot development, walking with crutches, and physical rehabilitation are all part of the post-operative guidelines. To regain range of motion and build muscles, physical therapy incorporates both strengthening and range-of-motion activities. The day following surgery, physical therapy may start to help the patient get in and out of bed and learn how to use crutches safely. In order to promote bone healing following surgery, crutch walking requires using crutches without placing any weight on the operated limb. After a few weeks, it will be encouraged to make the transition to partial weight bearing on the operated leg.

What Are the Complications of a High Tibial Osteotomy?

Although there is a minimum overall probability of negative outcomes, HTO surgery does carry some risks.

• Fracture: There is a tiny chance that the bone could fracture during surgery and extend to the opposite side, rendering the fragments unstable. Modern implants, on the other hand, are sturdy enough to hold the broken pieces of bone together and provide good support as the bone heals.

• Infection: With the use of cutting-edge methods and an improvisational theater setting, the infection risk is minimal. If detected early, infection is probably treatable with antibiotics. In some circumstances, the implant might even need to be removed.

• Damage to Blood Vessels or Nerves: Though uncommon, it may result in weakness or numbness down the leg. Most people recover from that within three months.

• Lungs and Leg Clots: For the first 14 days following surgery, patients are prescribed medicine to prevent clots (deep vein thrombosis and pulmonary embolism).

• Stiffness: Muscle stiffness following surgery is typical and requires good physiotherapy treatment.

Conclusion

Active patients who are young or middle-aged can receive HTO to treat medial knee arthrosis. Careful patient selection, suitable osteotomy types, and precise surgical techniques are essential to HTO's effectiveness. The treatment has limitations, including restricted motion during the bone-union phase and the chance for delayed or nonunion. On the other hand, involvement in vigorous activities is permitted following bone union, and in 80 to 90 percent of patients, favorable short-term follow-up clinical results have been recorded. Additionally, HTO's positive results can be sustained for more than eight to ten years, postponing the requirement for TKA (total knee arthroplasty) conversion.