Knee Joint Cartilage Injuries

Articular cartilage is a smooth, shiny, and highly specialized tissue covering the ends of the bones forming the knee joint. Healthy cartilage minimizes friction between joint surfaces and plays a vital role in shock absorption and smooth movement.

Focal cartilage defects of the knee are challenging orthopedic conditions that can cause significant functional loss, especially in young and active individuals. As the cartilage becomes damaged, friction increases and symptoms such as:

• Pain that increases with movement,
• Locking or catching sensation,
• Swelling and joint effusion,
• Limited range of motion,
• Restrictions in sports and daily activities,

Cartilage contains no blood vessels or nerves, which means its self-healing capacity is extremely limited. Many cartilage injuries therefore do not heal on their own and may progress, making surgical treatment necessary.

Diagnosis and Radiological Evaluation

Accurate treatment planning requires a detailed clinical evaluation including the patient’s complaints, trauma history, physical examination findings, and radiological studies.

Main imaging methods include:

• X-ray: Shows joint alignment, joint space narrowing, and signs of arthritis.
• MRI: Demonstrates the location, size and depth of the cartilage defect and any accompanying injuries such as ligament tears, meniscal tears, or bone marrow edema.
• CT Scan: Important for evaluating bony defects associated with cartilage injuries, particularly in cases considered for mosaicplasty or osteochondral allograft.

Treatment Options

Treatment selection depends on the location, size, and depth of the lesion, whether it is in a weight-bearing area, and the patient’s age and activity level.

Common treatment methods include:

1. Microfracture Technique

Small holes are made in the bone beneath the defect to stimulate formation of cartilage-like repair tissue. Preferred in small to medium lesions.

2. Mosaicplasty

Healthy osteochondral plugs taken from a non–weight-bearing region are transplanted into the damaged area. Effective in medium-sized focal defects.

3. Scaffold (Matrix) Techniques

A biological scaffold is applied to the defect, acting as a supportive structure that the patient's own cells populate over time.

4. ACI – Autologous Chondrocyte Implantation

Cartilage cells taken from the patient are cultured in a laboratory and re-implanted into the defect. Used for larger cartilage defects.

5. Mesenchymal Stem Cell Therapy

Stem cells are applied to support and enhance the cartilage repair process.

6. Osteochondral Allograft Transplantation

Fresh donor cartilage-bone tissue is transplanted into the defect. One of the most effective options for large or complex defects.

None of the current techniques can fully regenerate original hyaline cartilage. However modern surgical methods can produce high-quality functional repair tissue with excellent clinical outcomes.

Postoperative Recovery

• Controlled knee motion is initiated early after surgery.
• Crutches are usually required for 4–8 weeks, depending on the procedure.
• Full weight-bearing varies according to the technique.
• Physical therapy is crucial for optimal recovery.

Rehabilitation focuses on strengthening exercises, restoring range of motion, balance and proprioception training, and gradual return to sports activities.

FAQ – Knee Cartilage Injuries