Osteotomy for Knee Realignment: Indications, Techniques, and Outcomes

Introduction

Knee realignment surgery, commonly referred to as osteotomy, is a critical surgical procedure designed to alleviate pain and restore function in patients suffering from knee conditions, particularly those involving osteoarthritis. This procedure is often indicated for younger patients with localized wear and tear on one side of the knee. By realigning the knee joint, osteotomy helps to redistribute weight across the knee, delaying or potentially avoiding the need for a total knee replacement.

Indications

Knee osteotomy is primarily indicated in patients with unicompartmental osteoarthritis, where only one side of the knee joint is affected, typically the medial (inner) compartment. The procedure is most effective in younger, active patients under the age of 60 who wish to maintain their level of physical activity and avoid the limitations of knee replacement. Other indications include:

1. Varus or Valgus Deformities: Patients with significant bow-legged (varus) or knock-kneed (valgus) deformities may benefit from realignment to balance the load on the knee joint.
2. Post-Traumatic Arthritis: Osteotomy may be indicated in cases where trauma has led to arthritis in a specific compartment of the knee.
3. Ligamentous Injuries: Patients with chronic instability due to ligamentous injuries, such as those affecting the anterior cruciate ligament (ACL), may benefit from an osteotomy to redistribute forces and improve joint stability.

Preoperative Evaluation

A thorough preoperative evaluation is crucial to ensure the success of knee osteotomy. The evaluation should include:

1. Clinical Examination: A detailed physical examination should assess the range of motion, ligament stability, and the presence of deformities. The alignment of the knee should be measured both clinically and radiographically.
2. Imaging: Weight-bearing X-rays of the entire leg are essential to assess the degree of deformity and the affected compartment. MRI and CT scans may be utilized to evaluate the condition of the cartilage and the underlying bone structure.
3. Patient Selection: Ideal candidates are those who have localized osteoarthritis, are physically active, and wish to delay knee replacement. Patient expectations and their understanding of the procedure and its outcomes should be carefully managed.

Contraindications

Certain conditions and factors may contraindicate knee osteotomy:

1. Advanced Osteoarthritis: Patients with tricompartmental osteoarthritis, where all three compartments of the knee are affected, are not suitable candidates.
2. Severe Obesity: Excessive body weight can place undue stress on the knee joint, reducing the efficacy of the procedure and increasing the risk of complications.
3. Infection or Poor Bone Quality: Active infections or poor bone quality, such as in cases of osteoporosis, are contraindications due to the increased risk of poor healing and complications.
4. Limited Range of Motion: Patients with significant stiffness or limited range of motion may not benefit from the procedure.

Surgical Techniques and Steps

Knee osteotomy can be performed using different techniques, depending on the location of the deformity and the specific needs of the patient. The two main types of osteotomies are High Tibial Osteotomy (HTO) and Distal Femoral Osteotomy (DFO).

1. High Tibial Osteotomy (HTO):
   • Indication: Primarily used for patients with varus deformity (bow-legged) affecting the medial compartment.
   • Procedure:
     • An incision is made on the upper part of the tibia.
     • The surgeon uses a guide to create a precise bone cut (osteotomy) in the tibia.
     • The bone is then realigned to shift the weight from the damaged medial compartment to the healthier lateral compartment.
     • The osteotomy is held in place using metal plates and screws.
   • Postoperative Care: Patients typically require crutches for 6-8 weeks, with gradual weight-bearing as the bone heals.
2. Distal Femoral Osteotomy (DFO):
   • Indication: Used for patients with valgus deformity (knock-kneed) affecting the lateral compartment.
   • Procedure:
     • An incision is made on the lower part of the femur.
     • Similar to HTO, a bone cut is made, and the femur is realigned to shift weight from the damaged lateral compartment to the medial compartment.
     • The osteotomy is stabilized with plates and screws.
   • Postoperative Care: Similar to HTO, with a focus on gradual rehabilitation and physical therapy.

Postoperative Care

Postoperative care is critical to ensure a successful outcome. The care regimen typically includes:

1. Pain Management: Pain relief is managed using a combination of analgesics and anti-inflammatory medications.
2. Rehabilitation: A structured physical therapy program is essential to restore strength, range of motion, and function. Weight-bearing is gradually introduced based on the surgeon’s assessment of bone healing.
3. Monitoring: Regular follow-up appointments with X-rays are necessary to monitor bone healing and ensure that the osteotomy is stable.
4. Activity Modification: Patients are advised to avoid high-impact activities that could jeopardize the success of the surgery. Low-impact activities such as swimming and cycling are encouraged.

Possible Complications

As with any surgical procedure, knee osteotomy carries certain risks and potential complications:

1. Infection: Postoperative infections can occur, necessitating prompt treatment with antibiotics or further surgical intervention.
2. Non-Union or Malunion: The bone may fail to heal properly, either not fusing (non-union) or healing in an incorrect position (malunion).
3. Nerve or Vascular Injury: There is a risk of damage to the nerves or blood vessels around the knee during surgery.
4. Thrombosis: Deep vein thrombosis (DVT) is a potential complication, particularly in the lower extremities.
5. Hardware Irritation: The metal plates and screws used to stabilize the osteotomy may cause irritation or discomfort, sometimes requiring removal after the bone has healed.

Different Techniques

Several techniques and variations of knee osteotomy have been developed to optimize outcomes and minimize complications:

1. Closing Wedge Osteotomy: This technique involves removing a wedge of bone to close the gap and realign the knee. It is a traditional approach but can shorten the limb slightly.
2. Opening Wedge Osteotomy: A wedge of bone is created by opening the bone on the opposite side of the deformity. This method allows for more precise correction and limb length preservation.
3. Dome Osteotomy: Involves creating a dome-shaped cut in the bone, allowing for multiplanar correction of the deformity.
4. Tomofix Plate: A specialized plate used in opening wedge osteotomies, providing stable fixation and allowing for early weight-bearing.

Prognosis and Outcome

The prognosis for patients undergoing knee osteotomy is generally positive, particularly when the procedure is performed in carefully selected patients. Key factors influencing outcomes include:

1. Patient Selection: Younger, active patients with localized osteoarthritis and good bone quality tend to have the best outcomes.
2. Surgical Technique: The precision of the osteotomy and the stability of the fixation are crucial for optimal results.
3. Rehabilitation: A rigorous and well-supervised rehabilitation program is essential to restore function and strength.

Studies have shown that knee osteotomy can provide significant pain relief and improve function, with many patients able to return to their desired level of activity. The procedure can delay or even prevent the need for total knee replacement, particularly in younger patients.

Alternative Options

For patients who are not suitable candidates for knee osteotomy or prefer other options, alternative treatments include:

1. Total Knee Replacement (TKR): Recommended for patients with advanced osteoarthritis affecting multiple compartments of the knee.
2. Unicompartmental Knee Arthroplasty (UKA): A partial knee replacement that targets the affected compartment while preserving the healthy parts of the knee.
3. Physical Therapy and Injections: Non-surgical options such as physical therapy, corticosteroid injections, and hyaluronic acid injections may provide temporary relief.
4. Cartilage Repair Techniques: Procedures such as microfracture, autologous chondrocyte implantation (ACI), and osteochondral grafting may be considered in specific cases.

Average Cost

The cost of knee osteotomy varies depending on factors such as the surgeon’s expertise, the hospital or surgical facility, and geographic location. In the United States, the cost typically ranges from $10,000 to $20,000, including surgery, hospitalization, and rehabilitation. Costs may be lower in other countries, but it’s important to consider the quality of care and potential travel expenses for international patients.

Recent Advances

Recent advances in knee osteotomy have focused on improving surgical precision, reducing recovery times, and enhancing patient outcomes:

1. Computer-Assisted Surgery (CAS): The use of computer-assisted navigation systems allows for more precise cuts and alignments, leading to better outcomes.
2. Robotic-Assisted Surgery: Robotic systems provide real-time feedback and assistance during surgery, enhancing precision and reducing the risk of complications.
3. Biologic Augmentation: The use of biologic agents such as platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) is being explored to enhance healing and reduce recovery times.
4. Minimally Invasive Techniques: Advances in surgical techniques have led to less invasive approaches, reducing pain, scarring, and recovery times.