McMurray Osteotomy: Uses, Procedure, Recovery, and Outcomes

What is a McMurray osteotomy used for?

A McMurray osteotomy, specifically referring to a high tibial osteotomy (HTO) that shifts the mechanical axis of the knee, is primarily used to treat medial compartment osteoarthritis in younger, active individuals by realigning the lower limb and offloading the damaged part of the knee joint.

Understanding the McMurray Osteotomy: A Surgical Overview

The term "McMurray osteotomy" historically refers to a specific type of osteotomy (bone cut) performed near the knee, often associated with the work of Dr. T.P. McMurray in the early 20th century, particularly in the context of meniscal injuries. However, in contemporary orthopedic and exercise science contexts, when discussing "McMurray osteotomy" in relation to knee arthritis, it typically refers to a high tibial osteotomy (HTO). This procedure involves surgically cutting and realigning the tibia (shin bone) just below the knee joint. The primary goal is to change the angle of the lower leg, thereby shifting the weight-bearing load from a damaged, arthritic compartment of the knee to a healthier one.

Primary Indications: Why is it Performed?

The McMurray osteotomy (HTO) is a limb-sparing procedure indicated for specific patient profiles and knee conditions:

• Medial Compartment Osteoarthritis: This is the most common indication. Patients with medial compartment osteoarthritis often develop a "bow-legged" or varus deformity, where the weight-bearing axis of the leg shifts excessively towards the inner (medial) side of the knee. This concentrates stress on the already damaged medial cartilage, accelerating degeneration and increasing pain. The osteotomy aims to correct this alignment.
• Preservation of Native Knee Joint: Unlike a total knee replacement (TKA), an osteotomy preserves the patient's own knee joint structures. It is often considered a "bridge" procedure, delaying the need for a TKA for many years.
• Younger, Active Patients: HTO is particularly suitable for individuals typically under 60 years of age who are active and wish to maintain a high level of physical activity. Total knee replacements have a finite lifespan, and performing them in younger patients might necessitate revision surgeries later in life.
• Specific Ligamentous Instabilities: In some cases, an osteotomy may be used in conjunction with ligament reconstruction (e.g., ACL repair) to correct underlying malalignment that contributes to chronic instability or puts excessive stress on the reconstructed ligament.

The Biomechanical Principle: How It Works

The effectiveness of a McMurray osteotomy (HTO) lies in its ability to alter the biomechanics of the knee joint:

• Weight-Bearing Axis Shift: The core principle is to shift the mechanical axis of the limb. In a varus (bow-legged) knee, this axis passes through the medial compartment. By removing a wedge of bone from the upper tibia (or adding a wedge), the surgeon changes the angle of the tibia, effectively redirecting the weight-bearing line to pass through the healthier lateral (outer) compartment of the knee.
• Unloading the Damaged Compartment: This shift in the mechanical axis reduces the compressive forces on the arthritic medial compartment, thereby decreasing pain and potentially slowing the progression of cartilage degeneration in that area.
• Stimulating Bone Healing: The act of cutting the bone and allowing it to heal can also stimulate biological processes that may contribute to pain relief and improved joint health, though this is secondary to the mechanical offloading.
• Reducing Pain and Improving Function: By alleviating the excessive load on the damaged cartilage, patients typically experience significant pain reduction, improved walking mechanics, and enhanced ability to perform daily activities and even some sports.

Surgical Procedure: A Brief Overview

The McMurray osteotomy (HTO) is a complex orthopedic procedure that involves:

• Pre-operative Planning: Detailed X-rays and imaging are used to precisely measure the limb alignment and plan the exact angle and amount of bone to be cut or added.
• The Cut (Osteotomy): An incision is made on the inner side of the knee. A precise wedge of bone is either removed (closing wedge osteotomy) or a cut is made and opened to insert a bone graft or bone substitute (opening wedge osteotomy) from the upper tibia. The choice depends on the specific deformity and surgeon's preference.
• Fixation: Once the desired alignment is achieved, the bone fragments are stabilized using internal fixation devices, typically a metal plate and screws, to allow the bone to heal in its new position.
• Healing Phase: The bone typically takes several months to fully heal and consolidate.

Post-Operative Rehabilitation and Recovery

Rehabilitation is a critical component of successful recovery after a McMurray osteotomy (HTO). It is a structured, progressive process guided by a physical therapist:

• Immediate Post-Op (Weeks 0-6): Focus on pain management, protecting the surgical site, and initiating gentle range of motion exercises. Weight-bearing is typically restricted or non-weight-bearing, often requiring crutches or a walker.
• Early Phase (Weeks 6-12): Gradual progression to partial weight-bearing as bone healing progresses. Exercises focus on restoring full knee extension and flexion, and initiating isometric and light strengthening exercises for the quadriceps and hamstrings.
• Intermediate Phase (Months 3-6): Progression to full weight-bearing, gait retraining, and more advanced strengthening exercises targeting hip, knee, and ankle musculature. Balance and proprioception exercises are introduced.
• Late Phase (Months 6+): Functional training, sport-specific drills (if applicable), and gradual return to higher-impact activities, depending on the individual's goals and bone healing.

Potential Outcomes and Considerations

While effective, a McMurray osteotomy (HTO) has specific outcomes and considerations:

• Pain Relief and Function Improvement: The primary benefit is significant reduction in pain and improvement in knee function, allowing patients to resume many activities.
• Longevity of Results: HTO can effectively delay the need for a total knee replacement for 10-15 years or more in suitable candidates.
• Limitations and Risks:
  • Non-union or Delayed Union: The bone may not heal properly or may take longer than expected.
  • Infection: As with any surgery, there is a risk of infection.
  • Nerve or Vascular Damage: Though rare, damage to surrounding nerves or blood vessels can occur.
  • Stiffness: Some patients may experience persistent knee stiffness.
  • Overcorrection or Undercorrection: The alignment may not be perfectly achieved, potentially requiring further intervention.
  • Not a Permanent Solution: It does not cure arthritis but manages its symptoms and progression. The joint may eventually require a total knee replacement.
  • Impact on Future TKA: An osteotomy can sometimes make a future total knee replacement more technically challenging, though it does not preclude it.

Who is a Candidate for a McMurray Osteotomy?

Ideal candidates for a McMurray osteotomy (HTO) typically present with:

• Age: Usually younger than 60-65 years old.
• Activity Level: Active individuals who want to maintain a physically demanding lifestyle.
• Osteoarthritis Severity: Mild to moderate medial compartment osteoarthritis.
• Alignment: A clear varus (bow-legged) deformity.
• Ligamentous Integrity: Intact knee ligaments (ACL, PCL, MCL, LCL) are generally preferred for optimal stability post-surgery.
• Overall Health: Good general health with no contraindications to major surgery.

The decision to undergo a McMurray osteotomy (HTO) is a complex one, made in consultation with an orthopedic surgeon, considering the patient's individual condition, activity goals, and long-term prognosis.