Cartilage Injuries

Hyaline cartilage is a tissue in the human body that is found at the end of bones, within the joint. It is made up of a complex tissue that contains cells called chondrocytes and an extracellular matrix made up of several substances, mainly water, proteoglycans, glycosaminoglycans, including hyaluronic acid, and type II collagen. This matrix is produced by chondrocytes.

Cartilage plays a vital role in the health and function of the joints, allowing bones to glide smoothly and painlessly. However, cartilage injuries are common and can be debilitating. Due to the characteristics of cartilage tissue, which does not receive blood for nutrition, nerve endings or lymphatic vessels, its potential for spontaneous healing is low.

Fortunately, advances in medicine and research have allowed the development of several treatment options for cartilage injuries. Here, we will explore the different approaches available, from non-surgical treatments to advanced surgical procedures, as well as future prospects in the treatment of localized cartilage injuries, with a focus on the knee joint.

Types of Cartilage Injuries

Cartilage injuries can be divided into diffuse and localized. Injuries that diffusely affect the joint occur, for example, in diseases such as osteoarthritis or chondromalacia patella.

Osteoarthritis is a complex joint condition that initially involves cartilage wear, but affects the joint as a whole. Here on the website, there are some articles specifically about this problem (learn more about knee osteoarthritis here).

Chondromalacia of the patella is also a problem that occurs due to chronic overload of the joint between the kneecap and the femur. We will not focus on this topic here, since there are several articles on it here on the website (check out more information about chondromalacia patella here).

Lesions that affect the articular cartilage in a localized or focal manner are those that are limited to a specific area of the joint. They can be partial or full thickness, reaching the bone behind the cartilage.

What does the patient feel?

Symptoms resulting from focal lesions of the knee cartilage can be diverse, but normally there are:

Joint pain;
Joint effusion (increased volume);
Sensation of knee locking;
Grinding;
Perception of a loose fragment inside the knee.

How the Diagnosis is Made

The diagnosis of a cartilage injury is made first by understanding the patient's symptoms and in what situations they occur. It is very important to know if there was any type of trauma related to the onset of symptoms, such as a knee twist.

A physical examination is also very important, indicating a possible injury and, mainly, its location within the joint.

After taking the patient's history, performing the physical examination and suspecting a cartilage injury, some imaging exams may be necessary, which we will discuss in the following topic.

Tests Required for Diagnosis

Some imaging exams are extremely important for diagnosing a cartilage injury and planning the treatment. The main and most frequently requested are X-rays, computed tomography and magnetic resonance imaging. X-rays provide important information, such as whether there is significant involvement of the bone, whether there is wear and tear on other parts of the joint and the alignment of the limb. Computed tomography is a good exam to determine whether there are loose fragments within the joint fluid and also if there is bone involvement. However, magnetic resonance imaging is the exam that provides us with the most information about the characteristics of the injury. Through it, data such as the size and depth of the injury and the presence of other associated injuries can be obtained. Thus, MRI becomes an important tool for planning treatment.

Treatment

The treatment of focal cartilage injuries should be considered taking into account some aspects. Since this is a very common finding in knee imaging exams, when the patient has a small lesion that does not cause symptoms, often only clinical monitoring of this condition is indicated.

However, larger injuries can cause significant limitations and cause quick wear of the compartment in which they are located and, therefore, deserve targeted treatment.

Non-Surgical Treatment

Physiotherapy: Physiotherapy plays a fundamental role in the treatment of knee cartilage lesions. Exercises help to strengthen the muscles around the joint, reduce pain, improve mobility and mechanical overload.

Medications: Non-hormonal anti-inflammatory drugs, such as ketoprofen, nimesulide, among others, can be prescribed to reduce inflammation and pain. Corticosteroid injections can also provide temporary relief and joint infiltrations with hyaluronic acid can be considered in specific cases.

Supplements: Supplementation with a combination of chondroitin and glucosamine or type II collagen has been used to improve cartilage health, although the results found in the medical literature are variable.

Surgical Treatment

There are several surgical techniques available for the treatment of localized cartilage injuries. The indication depends mainly on the size and location of the injury in the joint. The most frequently performed are the following:

Debridement: This is a procedure performed by arthroscopy, that is, by video, which aims to remove unstable fragments of cartilage present in the injury.

Radiofrequency cauterization: This is a procedure in which radiofrequency is used to produce a controlled burn of unstable and non-viable fragments of the injured cartilage.

Microfractures: This procedure involves making small perforations in the area of the injury. These perforations release stem cells into the cartilage lesion bed, which serve to stimulate the growth of fibrocartilaginous tissue.

$Microfracture$

Autologous Matrix-Induced Chondrogenesis (AMIC): This is a procedure in which stimulation techniques, such as microfracture (described above), are used to release cells from the underlying bone. The resulting superclot contains what are known as stem cells, which can help to regenerate cartilage. The superclot is covered by a collagen membrane to protect the cells and keep them in place.

Osteochondral Autograft Transfer System: Also known as mosaicplasty, this is a procedure in which cylinders containing cartilage and bone are removed from healthy areas of the joint and transferred to the injured area.

Autologous Minced Cartilage Implantation: This is a procedure in which healthy cartilage fragments containing viable chondrocytes are collected and minced. They are then used to fill the cartilage defect.

Autologous Chondrocyte Implantation: This is a treatment performed in two stages. In the first one, the cartilage tissue is collected and sent to the laboratory, where it undergoes cellular expansion. After expansion, a new surgical procedure is performed so that the tissue is implanted in the injured area.

Future Perspectives

Cartilage is a peculiar tissue, whose architecture is unique in the human body. Its roles of resisting compression forces and reducing friction are very difficult to reproduce. Therefore, ongoing research is exploring new techniques and approaches for the treatment of cartilage injuries in the knee.

Some of the future prospects include:

Biological Therapies: Stem cell-based therapies from various tissues in the body, such as adipose tissue and bone marrow, have been developed to improve the regeneration potential of cartilage. Such therapies are most commonly studied for the treatment of diffuse lesions, such as osteoarthritis, but they have a role in the treatment of localized cartilage defects.

Tissue Engineering: The development of artificial cartilage tissues in the laboratory is being studied as a promising alternative for cartilage defects.

Genetic Therapies: Advances in genomic medicine may allow personalized treatments, adapted to the genetics of each patient, targeting modifications in specific cells related to cartilage regeneration.

Conclusion

Treatment for knee cartilage injuries has evolved significantly over the years, offering a variety of options, from non-surgical treatments to advanced surgical procedures. The choice of treatment will depend on the severity of the injury, the patient’s age, desired physical activity, and other individual factors. As research advances, new insights are emerging that promise more effective and personalized approaches to restoring knee cartilage health. However, it is important to consult with a qualified healthcare professional to determine the best approach for each specific case.