What is it?
Chondromalacia Patella is the gradual softening and degeneration of the cartilage located behind the patella (kneecap). As the knee bends and straightens, the patella slides over the femur (thigh bone), forming what is known as the patellofemoral joint. The cartilage on the underside of the patella facilitates this movement, ensuring it is smooth and pain-free. However, over time, this cartilage can become softer and thinner due to factors such as overuse, muscular weakness, or alignment issues, leading to pain at the front of the knee. The term Chondromalacia Patella describes the structural damage to the patellofemoral joint, while Patellofemoral Pain Syndrome (PFPS) refers to the early stages of the condition, where symptoms arise without obvious structural damage.
Anatomy
The patella rests on the femur and is surrounded by the quadriceps tendon, which connects the quadriceps muscles to the top of the kneecap. Below the patella is the patellar tendon, connecting the kneecap to the tibia (shin bone). Although these tendons are distinct, their actions are interrelated. For example, tightness in the quadriceps can increase tension on the patellar tendon.
The quadriceps muscles cause the knee to straighten and the patella to glide along the femur. The underside of the patella is lined with articular cartilage, aiding smooth movement and maintaining proper alignment of the patella within the femoral groove. Two quadriceps muscles, the Vastus Medialis Oblique (VMO) and the Vastus Lateralis (VL), play essential roles in keeping the patella centred. An imbalance in these muscles can cause the patella to be pulled off-centre, leading to abnormal tracking and increased stress on the cartilage.
Signs & Symptoms
Symptoms of Chondromalacia Patella often include:
- Pain under and around the edges of the kneecap.
- Increased pain with repetitive bending and straightening of the knee.
- Discomfort during activities like climbing stairs, running, or squatting.
- Pain after prolonged knee bending, such as when sitting for long periods.
- A grinding or crunching sensation when bending the knee.
Causes and Contributing Factors
Chondromalacia Patella is a degenerative condition that develops gradually, often due to excessive loading of the patellofemoral joint, causing wear and tear. This overloading can stem from several factors:
Activity and Sport
Sports and activities that involve repetitive knee movements, such as running, cycling, rowing, soccer, and tennis, place continuous stress on the patellofemoral joint. Long-term participation in these activities can naturally lead to joint degradation. Ageing also contributes to the degeneration of cartilage.
Quadriceps Weakness
Imbalances in the quadriceps muscles can result in abnormal patella tracking. The quadriceps control patella movement and keep it aligned within the femoral groove. Weakness or injury to these muscles, especially the VMO, can cause the patella to be pulled to one side, increasing pressure on the articular cartilage on the opposite side.
Hip Weakness
Weakness in the hip muscles, such as the gluteals and the tensor fasciae latae (TFL), can also contribute. These muscles influence the iliotibial band (ITB), a thick band of tissue running down the outside of the thigh, which attaches just below the knee. When functioning correctly, these muscles help align the knee, distributing forces evenly between the ankle, knee, and hip. If they are weak or not activating properly, the knee may collapse inward (knee valgus), altering patella tracking and increasing patellofemoral joint stress.
Anatomical Variations
The Q angle refers to the angle between the femur and the tibia. This angle varies from person to person, and women typically have a larger Q angle than men. An increased Q angle can cause the patella to track laterally (towards the outside), leading to heightened pressure on one side of the cartilage. Additionally, variations in the femoral groove, such as a shallower groove, can also affect patella alignment and increase the risk of dislocation.
Prognosis
Chondromalacia Patella is a manageable condition, especially when addressed early. Mild cases often respond well to conservative treatments, with symptoms improving within a few weeks to months. However, more severe or long-standing cases, especially those involving structural changes or significant cartilage damage, may take longer to recover or may require surgical intervention. Full recovery depends on factors such as adherence to rehabilitation programs, modifying activities, and addressing underlying causes such as muscle imbalances or anatomical factors.
Treatment
Conservative Management
Non-operative management is typically effective in treating Chondromalacia Patella. The initial goal is to control pain and inflammation, followed by addressing muscle weaknesses or alignment issues that contribute to the problem. Key aspects of conservative management include:
- Activity Modification: Avoiding or reducing activities that aggravate symptoms, such as prolonged sitting or repetitive squatting, to allow the cartilage to recover.
- Load Management: Gradually increasing load-bearing activities to reduce inflammation and promote healing.
- Bracing or Taping: Supportive taping or bracing techniques may be used to assist in patella alignment during movements, helping to reduce pain during activities.
- Physiotherapy: Rehabilitation focuses on strengthening the quadriceps and hip muscles to improve patellar tracking and knee stability. Specific exercises may target the VMO to enhance its function in keeping the patella centred.
- Manual Therapy: Techniques such as soft tissue massage, dry needling, and joint mobilisations may be used to alleviate muscular tightness, enhance joint range of motion, and reduce pain.
Surgical Options
Surgery may be considered when conservative treatments fail to provide relief. Surgical options depend on the specific underlying cause and may include:
- Cartilage Restoration: Procedures that aim to repair or restore the degraded articular cartilage.
- Lateral Release: If lateral patellar tracking is the issue, this procedure releases tight tissues pulling the patella out of alignment.
- Ligament Tightening: In cases of recurrent patellar dislocation, tightening the surrounding ligaments may enhance stability and prevent future dislocations.
Information is provided for educational purposes only. Always consult your physiotherapist or other health professional.
References:
A Patient’s Guide to Chondromalacia Patella. (n.d.). The Central Orthopedic Group. Retrieved October 10, 2024, from https://centralorthopedicgroup.com/wp-content/themes/central-14/pdf/knee/knee_knee_patella_chondromalacia.pdf