Patellectomy: Procedure, Recovery, and Living Without a Kneecap

What is Patellectomy?

Patellectomy is a surgical procedure involving the complete or partial removal of the patella, commonly known as the kneecap. It is typically considered a last-resort intervention for severe, irreparable damage to the patella that has not responded to other forms of treatment.

Understanding the Patella's Role

The patella is a sesamoid bone, meaning it is embedded within a tendon—specifically, the quadriceps tendon. It sits anterior to the knee joint, articulating with the trochlear groove of the femur. Its primary biomechanical function is to increase the mechanical advantage (leverage) of the quadriceps femoris muscle group. By lengthening the lever arm of the quadriceps, the patella allows the quadriceps to generate more torque for knee extension with less force. It also provides a protective barrier for the knee joint and helps distribute compressive forces across the femoropatellar joint.

Indications for Patellectomy

While considered a salvage procedure, patellectomy may be indicated in specific, severe circumstances where the benefits of pain relief and improved function outweigh the significant loss of mechanical advantage. Common indications include:

• Severe, Comminuted Patellar Fractures: Fractures where the patella is shattered into multiple pieces, making internal fixation (repair) impossible or highly unlikely to succeed.
• Failed Patellar Fixation: Cases where previous surgical attempts to repair a fractured patella have failed, leading to non-union or significant functional impairment.
• Intractable Patellofemoral Pain: Chronic, severe pain originating from the patellofemoral joint that has not responded to extensive conservative management (e.g., physical therapy, bracing, injections) or less invasive surgical procedures. This often involves severe chondromalacia or osteoarthritis of the patella.
• Patellar Osteonecrosis: A rare condition where the bone tissue of the patella dies due to a loss of blood supply.
• Patellar Tumors: In very rare instances, the presence of a tumor within the patella may necessitate its removal.
• Severe Patellar Infection: Uncontrolled infection within the patella that cannot be eradicated by other means.

The Surgical Procedure

Patellectomy is typically performed as an open surgical procedure. The surgeon makes an incision over the front of the knee. The patella is then carefully dissected from its surrounding soft tissues, including the quadriceps tendon superiorly and the patellar ligament (which connects the patella to the tibia) inferiorly. Once the patella is removed, the quadriceps tendon is directly sutured to the patellar ligament. This re-establishes the continuity of the extensor mechanism, allowing the quadriceps muscle to still extend the knee, albeit with significantly reduced efficiency. In some cases, a partial patellectomy may be performed if only a portion of the bone is severely damaged.

Post-Operative Recovery and Rehabilitation

Rehabilitation following a patellectomy is a long and challenging process, crucial for optimizing functional outcomes. It typically involves several phases:

• Initial Immobilization and Protection: Immediately post-surgery, the knee is often immobilized in extension using a brace to protect the surgical repair. Weight-bearing may be restricted. The focus is on pain and swelling management.
• Early Motion and Gentle Strengthening: Gradually, controlled range of motion exercises are introduced, often within a brace. Isometric quadriceps exercises are initiated to prevent atrophy without stressing the repair.
• Progressive Strengthening: As healing progresses, more dynamic strengthening exercises are added, targeting the quadriceps, hamstrings, glutes, and core. Emphasis is placed on regaining full knee extension and improving strength.
• Proprioception and Balance Training: Crucial for restoring neuromuscular control and stability, especially given the altered biomechanics.
• Functional Training: Activities that mimic daily movements, such as walking, stair climbing, and eventually more complex movements, are incorporated.
• Activity Modification: Patients must understand that high-impact activities or those requiring significant knee flexion under load (e.g., deep squats, jumping, running) may be difficult or contraindicated long-term.

The entire rehabilitation process can take many months to over a year, requiring consistent effort and adherence to a physical therapy program.

Functional Implications and Potential Outcomes

The removal of the patella has profound biomechanical consequences:

• Reduced Quadriceps Leverage: The most significant impact is the loss of the patella's mechanical advantage. This means the quadriceps must work much harder to produce the same amount of knee extension force, leading to a significant decrease in power and endurance.
• Altered Knee Kinematics: The absence of the patella changes the normal mechanics of the knee joint, potentially leading to increased stress on the tibiofemoral (femur-tibia) joint and a higher risk of developing osteoarthritis in that compartment over time.
• Gait Abnormalities: Patients often develop a quadriceps avoidance gait, where they try to minimize the load on the knee during walking, which can lead to compensatory movements and stress on other joints.
• Persistent Weakness and Fatigue: Despite diligent rehabilitation, some degree of quadriceps weakness and fatigue is common and often permanent.
• Pain Relief: For patients undergoing patellectomy due to intractable pain, the procedure can often provide significant relief, though some residual discomfort or stiffness may persist.
• Activity Limitations: Patients typically experience difficulty with activities requiring strong knee extension, such as climbing stairs, rising from a chair, squatting, running, and jumping.

Living Without a Patella: Exercise Considerations

For individuals who have undergone a patellectomy, exercise and physical activity require careful consideration and adaptation:

• Prioritize Low-Impact Activities: Activities like cycling (with appropriate seat height), swimming, and elliptical training are excellent choices as they provide cardiovascular benefits and strengthen muscles with minimal stress on the knee.
• Focus on Comprehensive Lower Body Strength: Beyond the quadriceps, it is critical to maintain robust strength in the hamstrings, glutes, and core muscles to provide stability and support for the knee joint.
• Emphasize Proprioception and Balance: Neuromuscular control exercises are vital to compensate for the altered joint mechanics and improve stability during movement.
• Modify High-Load Activities: Deep squats, lunges, and plyometric exercises (jumping, bounding) should be approached with extreme caution or avoided, as they place excessive stress on the compromised extensor mechanism.
• Listen to Your Body: Pain is an indicator of excessive stress. Activities should be progressed slowly and symptoms carefully monitored.
• Professional Guidance is Essential: Working closely with a physical therapist and a knowledgeable fitness professional experienced in post-surgical rehabilitation is paramount to developing a safe and effective exercise program tailored to individual capabilities and limitations.

Conclusion

Patellectomy is a significant and irreversible surgical procedure that fundamentally alters the biomechanics of the knee joint. While it can be a life-changing intervention for individuals suffering from severe, intractable patellar pathology, it comes with inherent functional limitations, primarily due to the loss of quadriceps leverage. For those living without a patella, a dedicated and lifelong commitment to targeted rehabilitation, strength training, and activity modification is essential to maximize function, minimize compensatory issues, and maintain a good quality of life.