About Articular Cartilage Injuries

Articular cartilage is the smooth, white connective tissue that covers the ends of bones in joints, allowing them to glide smoothly over each other. It acts as a shock absorber, enabling joints to withstand weight-bearing and movement. Articular cartilage has no direct blood supply, making it difficult to heal once injured.

Traumatic injuries: Direct impact or trauma can cause articular cartilage damage, such as a cartilage shear injury where a piece of cartilage shears off the bone.

Degenerative injuries: Progressive wear and tear over time can lead to cartilage softening, fragmentation, and eventual loss (osteoarthritis).

The Outerbridge classification system grades the severity of articular cartilage damage:

• Grade 0: Normal cartilage
• Grade 1: Cartilage softening and swelling
• Grade 2: Partial-thickness defect with surface fissures
• Grade 3: Deep partial-thickness defect down to subchondral bone (<1.5 cm diameter)
• Grade 4: Full-thickness cartilage loss exposing subchondral bone

Common Symptoms

• Pain and swelling in the affected joint
• Stiffness and reduced range of motion
• Catching, locking, or grinding sensations
• Instability or feeling of “giving way” in the joint

Diagnosis

• Physical examination to assess joint function and stability
• Imaging tests like X-rays and MRI to visualize cartilage damage
• Arthroscopy may be performed for direct visualization

Treatment

Non-surgical:

• Activity modification, physical therapy, NSAIDs for pain/inflammation

Surgical (for larger defects):

• Arthroscopic debridement to remove loose cartilage
• Marrow stimulation techniques like microfracture
• Osteochondral grafting (autograft or allograft)
• Autologous chondrocyte implantation (ACI) like Carticel

The goals are to relieve symptoms, restore joint function, and prevent or delay the onset of osteoarthritis.