Cartilage, a specialized connective tissue, plays a significant role in joint function by providing a smooth, low-friction surface that enables bones to glide over one another without direct contact. It also acts as a shock absorber, distributing forces during movement and weight-bearing. A full thickness cartilage defect represents a complete injury where the cartilage has been entirely worn away or damaged down to the underlying bone. Such damage can impact a joint’s ability to move freely and without discomfort.
Understanding Full Thickness Cartilage Defects
This type of damage most often occurs in weight-bearing joints such as the knee, ankle, and hip, though it can also affect the shoulder or elbow. Unlike other tissues, articular cartilage has a limited capacity for self-repair due to its lack of blood vessels, nerves, and lymphatic supply.
These defects frequently arise from acute trauma, such as direct blows to the joint, twisting injuries common in sports, or falls. While less common as a primary cause for full thickness defects, certain degenerative conditions, particularly advanced osteoarthritis, can eventually lead to widespread cartilage erosion down to the bone. Osteochondritis dissecans, where bone and overlying cartilage detach due to blood supply loss, also contributes to the formation of these defects.
Individuals experiencing a full thickness cartilage defect report localized pain, which worsens with activity or weight-bearing. Swelling around the affected joint, sometimes accompanied by stiffness, especially after periods of rest. Patients may also experience mechanical symptoms, such as clicking, popping, or grinding sounds during joint movement, or a sensation that the joint is “giving way” or momentarily locking.
Diagnosing Cartilage Damage
Diagnosing cartilage damage begins with a thorough clinical examination. During this examination, the doctor assesses the affected joint’s range of motion, stability, and tenderness to touch. They may perform specific maneuvers to reproduce symptoms and to gather clues about the injury’s extent and location.
Imaging techniques are then used to confirm the diagnosis and visualize the cartilage defect. Magnetic Resonance Imaging (MRI) is an effective non-invasive method for assessing cartilage integrity, providing detailed images showing the defect’s size, depth, and location. X-rays do not directly show cartilage but are used to rule out bone fractures, assess joint space, or identify other bone abnormalities. In some cases, arthroscopy, a minimally invasive surgical procedure, may be performed; a small camera is inserted into the joint to visualize the cartilage and confirm the diagnosis, and for simultaneous treatment.
Treatment Approaches for Cartilage Defects
Managing full thickness cartilage defects typically begins with non-surgical approaches aimed at symptom relief, though they do not repair the defect. Physical therapy can help strengthen surrounding muscles, improve joint stability, and restore range of motion, thereby reducing stress on the damaged area. Pain management strategies include nonsteroidal anti-inflammatory drugs (NSAIDs) for pain and inflammation. Activity modification, such as avoiding high-impact sports or prolonged weight-bearing, can mitigate symptoms. Injections, such as corticosteroids for inflammation or hyaluronic acid for joint lubrication, may offer temporary symptomatic relief.
Surgical interventions are often considered for full thickness defects, with various techniques aiming to stimulate new cartilage growth or replace damaged tissue. Marrow stimulation techniques, like microfracture, involve creating small holes in the subchondral bone to allow bone marrow stem cells to seep into the defect, forming fibrocartilage. Subchondral drilling is a similar procedure that promotes fibrocartilage formation. These methods are more effective for smaller defects, less than 2-4 square centimeters.
Osteochondral Autograft Transplantation (OATS), sometimes referred to as mosaicplasty, involves harvesting small plugs of healthy cartilage and underlying bone from a less weight-bearing area of the patient’s joint and transplanting them into the defect. This technique provides hyaline-like cartilage, which is closer to native articular cartilage. Autologous Chondrocyte Implantation (ACI) is a two-stage procedure; first, a small biopsy of healthy cartilage is taken and cultured to grow more chondrocytes. In the second stage, the multiplied cells are implanted into the defect, often under a periosteal flap or collagen membrane.
Additional surgical options include particulated juvenile articular cartilage (PJAC) transplantation, uses donor cartilage from young individuals, processed into small fragments for implantation. Allograft cartilage transplantation, using donor tissue from cadavers, is used particularly for larger defects where autograft sources are insufficient. These advanced surgical techniques restore a smoother joint surface and improve overall joint function.
Recovery and Long-Term Outlook
Recovery following treatment for a full thickness cartilage defect, especially surgical intervention, is a lengthy and demanding process with rehabilitation as a priority. Physical therapy is central to recovery, involving exercises to restore joint motion, strengthen muscles, and improve stability. Controlled weight-bearing, initiated with crutches or braces, is gradually increased over several weeks or months to protect healing tissue and allow integration. The total recovery period can range from several months to over a year, depending on the specific procedure, defect size, and individual patient factors.
The long-term outlook for individuals with full thickness cartilage defects varies, but the primary goals of treatment are to reduce pain, improve joint function, and delay or prevent the progression of osteoarthritis. Many patients experience pain relief and improved mobility following successful treatment and adherence to rehabilitation protocols. Factors influencing the outcome include the patient’s age, the size and location of the defect, the presence of other joint injuries, and compliance with post-operative instructions.
Ongoing management involves continued participation in low-impact activities and maintaining a healthy weight to minimize stress on the repaired cartilage. Regular follow-up appointments with a healthcare provider are necessary to monitor joint health and address emerging concerns. While treatments can improve quality of life, the repaired cartilage may not be identical to original healthy cartilage, and long-term monitoring and lifestyle adjustments may be necessary to preserve joint health.