One-step scaffold cartilage regeneration surgery

What is articular cartilage?

Articular cartilage, also known as joint cartilage, refers to the white tissue that covers the ends of bones, forming the joint. This specific type of cartilage is distinguished by its presence within the joint, as there are other forms of cartilage found elsewhere in the body. These include fibroelastic cartilage, which is found in structures like the meniscus; fibrocartilage, located at the attachment points of tendons and ligaments onto bones; elastic cartilage, present in the trachea; and physeal cartilage, which exists in the growth plate (present at the ends of growing bones of children and adolescents).

Each type of cartilage serves unique functions in the body, but articular cartilage plays a vital role in facilitating smooth joint movement and cushioning the bones during articulation*. Additionally, it plays a crucial role in transmitting loads to the underlying bone (called subchondral bone), ensuring effective distribution of forces during movement.

Articular cartilage is composed of several key components; consisting of specialized cells called chondrocytes, which are responsible for maintaining and repairing the cartilage tissue. Surrounding these cells is the extracellular matrix, which comprises of water, collagen, and proteoglycans. The majority of the matrix, approximately 90%, is composed of collagen, specifically type II collagen.

The functions of joint cartilage are vital for proper joint function and movement. Firstly, it serves to decrease friction between the articulating surfaces of the bones within the joint, allowing for smooth and seamless movement. Secondly, it plays a crucial role in distributing loads or forces evenly across the joint, preventing excessive stress on any specific area. Finally, the presence of healthy cartilage enables painless and unrestricted range of motion, facilitating comfortable and fluid movements of the joint. 

Why is articular cartilage susceptible to damage and why does it need to be treated?

The knee joint is where cartilage defects are predominantly observed. Nevertheless, the limited natural healing capacity of cartilage makes repairing articular cartilage defects a significant challenge, despite the existence of numerous proposed approaches.

Joint cartilage can be damaged through three main mechanisms:

1. Trauma - Traumatic damage can occur either directly or indirectly. Direct trauma refers to an excessive impact on the cartilage that immediately disrupts the surface. Examples include falls directly onto the knee, being struck by a hard object, or experiencing a direct blow to the knee in a motor vehicle accident. Indirect trauma involves damage to the cartilage due to twisting or shearing forces resulting from aggressive joint movements.
2. Wear and tear - Cartilage can be affected by chronic wear and tear over time. This can result from repetitive stress on the joint, such as being overweight, engaging in excessive physical activities or loading (such as excessive sports activities) and experiencing repeated cycles of inflammation seen in conditions like gout or inflammatory arthritis (e.g., rheumatoid arthritis).
3. Prolonged lack of movement - Joints can also be damaged due to prolonged immobilization or a lack of movement. This can occur in situations such as seen in stroke patients or individuals affected by injuries that require the joint to remain immobilized for an extended period such as those immobilized by fractures. 

What specific defect conditions are suitable for cartilage regeneration surgery?

When injured, cartilage tear or damage will eventually form a depression which are called defects (essentially holes in the joint cartilage due to injuries).

Criteria for effective cartilage regeneration surgery producing good results are:

1. The cartilage defects must be isolated and classified as grades III or IV, indicating they are suitable for surgical treatment due to their depth.
2. Patients should be aged between 15-55 years, meaning they’re for young and relatively young individuals.
3. The absence of diffuse osteoarthritis within the joint.
4. No presence of chronic diseases that may hinder proper healing, such as smoking, diabetes, or inflammatory conditions like gout, rheumatoid arthritis, lupus, or infection.

Importance of meeting the criteria:

The criteria mentioned above are crucial to facilitate the growth of new blood vessels that provide nourishment to the damaged area and support the development of new cartilage.

By considering these criteria, surgeons can determine the suitability of cartilage regeneration surgery and optimize the chances of successful outcomes.

What are the benefits of cartilage regeneration surgery? 

1. The benefits of cartilage regeneration surgery include: 
1. It allows the joint to heal naturally using minimally invasive keyhole surgery which involves very small incisions, allowing for faster recovery and less painful post operative period.
2. Repairing cartilage defects within the joint by employing membranes or scaffolds to cover them. The scaffolds promote the regeneration of new cartilage. This prevents the defects from worsening and potentially leading to osteoarthritis of the joint; ultimately reducing the need for more major and invasive procedures like knee replacement.
3. Resulting in the formation of new cartilage that closely resembles normal cartilage, enabling patients to experience a relatively pain-free life and engage in regular daily activities. The joint can function as normally as possible, providing a full range of motion.
4. Prolonging the lifespan of the joint, preserving its functionality and preventing further deterioration.
2. The treatment involves the following surgical procedures performed in the Operating Theatre under anesthesia:
1. Arthroscopy of the joint (referring to keyhole surgery, which is the insertion of a camera into the joint using minimally invasive techniques).
2. The joint is thoroughly examined to identify any abnormalities and grade the severity of cartilage defects or tears. If the defects are classified as grade III or IV, the torn cartilage and the base of the defect are carefully cleaned (debrided).
3. Next step involved harvesting liquefied bone graft from the iliac crest by aspiration and then seeded onto a Hyaluronic Acid Scaffold (membrane) – called Hyalofast.
4. The scaffold will then be implanted into the defective cartilage area and will regenerate into new cartilage, effectively covering the previously damaged region.

How is the healing process like after cartilage regeneration surgery?

1. Following the surgery, the patient will be fitted with a knee brace that keeps the knee fully extended.
2. The day after the surgery, the patient will begin physiotherapy and will be permitted to walk with the aid of crutches. They will need to use the knee brace and crutches for approximately 2-3 weeks before gradually transitioning to walking and moving normally.
3. To avoid placing excessive stress on the surgically treated cartilage, patients are instructed to only bear half of their body weight on the operated leg.
4. Patients are allowed to gradually bend and straighten the knee with assistance, known as passive knee movements, as tolerated.
5. The process of cartilage regeneration and maturation typically takes a minimum of 6 months, although the timeframe may vary among individuals based on their unique healing capacity. Some patients may heal earlier, while others may require more time.

Dr Izan Ibrahim

Orthopaedic & Trauma Surgeon, 

Gleneagles Hospital Kuala Lumpur 

(An ICRS Centre of Excellence)

(ICRS = International Cartilage Regeneration and Joint Preservation Society)

*Source:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445147/#:~:text=Articular%20cartilage%20is%20a%20thin,to%20the%20underlying%20subchondral%20bone. 

This article was first published on The Expat Magazine, September 2023 edition.