Patellectomy: Complete Kneecap Removal, Procedure, Recovery, and Risks

What is a Patellectomy?

A patellectomy is a surgical procedure involving the complete removal of the patella, or kneecap, typically performed as a last resort in cases of severe, irreparable damage or disease to the bone.

Anatomy of the Patella

To understand the implications of a patellectomy, it's essential to first grasp the role of the patella. The patella, commonly known as the kneecap, is a sesamoid bone embedded within the quadriceps tendon. It serves several crucial biomechanical functions:

• Mechanical Advantage: The patella acts as a fulcrum, increasing the lever arm of the quadriceps muscle, thereby enhancing the efficiency and mechanical advantage of knee extension. This allows the quadriceps to generate more force with less effort.
• Protection: It protects the knee joint, particularly the femoral condyles, from direct trauma.
• Guidance: It helps guide the quadriceps tendon and patellar ligament, ensuring smooth movement during knee flexion and extension.

What is a Patellectomy?

A patellectomy is the surgical excision of the entire patella. Unlike partial patellectomies, which remove only a portion of the bone, a complete patellectomy leaves the knee without its kneecap. This procedure fundamentally alters the biomechanics of the knee joint, particularly the extensor mechanism. Following removal, the quadriceps tendon is typically reattached directly to the patellar ligament (which connects the patella to the tibia) or directly to the tibia itself, effectively creating a continuous extensor mechanism.

Indications for Patellectomy

While once more common, patellectomy is now considered a salvage procedure, reserved for specific, severe conditions where conservative treatments or less invasive surgical options have failed or are not feasible. Primary indications include:

• Severe Comminuted Patellar Fractures: When the patella is shattered into multiple irreparable pieces, making reconstruction impossible or unlikely to yield a functional outcome.
• Chronic, Debilitating Patellofemoral Pain Syndrome: In rare, extreme cases where all other treatments (physical therapy, injections, arthroscopy, partial patellectomy) have failed to alleviate severe, life-altering pain. This is a highly controversial indication due to the significant biomechanical consequences.
• Severe Patellar Chondromalacia or Osteonecrosis: Extensive damage to the articular cartilage or bone death of the patella that is beyond repair.
• Patellar Tumors: Rarely, the presence of a tumor within the patella may necessitate its removal.

The Surgical Procedure

A patellectomy typically involves:

1. Incision: An incision is made over the front of the knee.
2. Patella Removal: The patella is carefully dissected from the surrounding quadriceps tendon and patellar ligament.
3. Tendon Reattachment: The quadriceps tendon is then meticulously reattached to the patellar ligament or directly to the tibial tubercle. This re-establishes the continuity of the extensor mechanism, allowing for knee extension.
4. Closure: The incision is closed in layers.

Post-Operative Recovery and Rehabilitation

Recovery after a patellectomy is prolonged and demanding, requiring dedicated physical therapy to regain as much function as possible. The rehabilitation process often involves several phases:

• Immediate Post-Op (Weeks 1-4): Focus on pain management, swelling reduction, and protecting the surgical site. Initial range of motion (ROM) exercises may be limited, often starting with passive or gentle active-assisted flexion. Weight-bearing may be restricted.
• Early Rehabilitation (Weeks 4-12): Gradual increase in active ROM, initiation of isometric quadriceps contractions, and light strengthening exercises for the quadriceps, hamstrings, and glutes. Proprioceptive exercises begin. The goal is to carefully restore knee extension strength without excessive strain on the reattached tendons.
• Intermediate Rehabilitation (Months 3-6): Progression to more challenging strengthening exercises (e.g., leg presses, squats with limited depth), balance training, and gait re-education. Emphasis on regaining functional strength and endurance.
• Advanced Rehabilitation and Return to Activity (Months 6+): Sport-specific drills, plyometrics, and agility training (if applicable). The focus shifts to optimizing functional movement patterns and preparing for a return to desired activities, though high-impact or pivoting sports may be difficult or impossible.

Key Challenges in Rehabilitation:

• Loss of Mechanical Advantage: The absence of the patella significantly reduces the efficiency of the quadriceps, requiring substantially more effort to achieve knee extension. This often leads to persistent quadriceps weakness.
• Altered Biomechanics: The knee joint mechanics are permanently altered, potentially leading to increased stress on other structures, such as the tibiofemoral joint.
• Scar Tissue Formation: Extensive scar tissue can limit ROM and cause discomfort.

Potential Risks and Complications

As with any major surgery, patellectomy carries risks, including:

• Infection: Risk of surgical site infection.
• Deep Vein Thrombosis (DVT): Blood clots in the leg.
• Nerve or Blood Vessel Damage: Injury to surrounding neurovascular structures.
• Persistent Pain: Despite the surgery, chronic knee pain can persist.
• Knee Stiffness (Arthrofibrosis): Formation of excessive scar tissue leading to restricted range of motion.
• Quadriceps Weakness and Atrophy: Significant and often permanent reduction in quadriceps strength.
• Gait Abnormalities: Altered walking patterns due to biomechanical changes.
• Accelerated Osteoarthritis: Increased risk of developing degenerative changes in the tibiofemoral joint due to altered load distribution.

Long-Term Implications for Movement and Exercise

Individuals who undergo a patellectomy face significant long-term implications for their movement and exercise capacity:

• Reduced Knee Extension Strength: This is the most profound and lasting effect. Activities requiring powerful knee extension, such as jumping, sprinting, or climbing stairs, will be significantly more challenging.
• Difficulty with Deep Knee Flexion: Full knee flexion may be limited due to scar tissue or altered soft tissue tension.
• Compensatory Movements: The body may develop compensatory strategies, placing increased stress on other joints (e.g., hip, ankle, contralateral knee) or muscle groups, potentially leading to secondary issues.
• Impact on High-Demand Activities: Participation in high-impact sports, activities requiring rapid changes in direction, or heavy resistance training involving the knee extensors may be severely limited or impossible.
• Importance of Modified Exercise: Exercise programs must be carefully tailored to account for the altered biomechanics. Emphasis should be placed on:
  • Low-Impact Activities: Cycling, swimming, elliptical training.
  • Strengthening Other Muscle Groups: Focus on hip extensors, abductors, adductors, and core stability to support the knee.
  • Proprioception and Balance: Crucial for maintaining stability and preventing falls.
  • Gradual Progression: Extremely slow and cautious progression of load and intensity.

Alternative Treatments

Before considering a patellectomy, a range of conservative and less invasive surgical options are typically explored:

• Conservative Management: Physical therapy, bracing, activity modification, anti-inflammatory medications, and injections (corticosteroids, hyaluronic acid, PRP).
• Partial Patellectomy: Removal of only the damaged portion of the patella, preserving more of the original biomechanics.
• Patellofemoral Joint Replacement: In some cases of severe, isolated patellofemoral arthritis, a prosthetic replacement of the patella and trochlear groove may be considered.
• Tibial Tubercle Osteotomy: A procedure to realign the patella and reduce stress on the patellofemoral joint.

Conclusion

A patellectomy is a major surgical intervention involving the complete removal of the kneecap. While it can be a necessary salvage procedure for severe, irreparable patellar damage, it permanently alters knee biomechanics, leading to a significant and often permanent reduction in quadriceps strength and functional capacity. Rehabilitation is extensive and challenging, and individuals must adapt their movement patterns and exercise routines for the long term. It is a procedure of last resort, undertaken only when all other treatment options have been exhausted.