What is a Biological Knee Replacement?
Loss of meniscal tissue and breakdown of articular cartilage in the knee joint due to damage by injury, wear and tear, or arthritic conditions is probably the most common reason for an individual to undergo knee replacement.
The knee is the most common location for cartilage restoration. Biologic knee replacement in principle involves restoration of the meniscus and articular cartilage.
Artificial knee replacement is a surgical procedure where defective knee joint surfaces are completely replaced with an artificial joint made of metal or plastic to resolve a painful knee condition.
Biological knee replacement is an alternative to artificial knee replacement where the damaged knee joint is reconstructed biologically (i.e. without the need for an artificial knee replacement). This is done by replacing the missing meniscus with a meniscal transplantation from a donor cartilage and covering the areas of worn out articular cartilage with an articular cartilage graft prepared by your own tissue (autograft) or a donor tissue (allograft).
Anatomy
The knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these 3 bones where they meet are covered with articular cartilage, a smooth substance that protects the bones and enables them to move smoothly. The meniscal cartilage is located between the femur and tibia and functions as "shock absorbers" that cushion the knee joint. Large ligaments hold the bones together and provide stability.
Who might be suitable for a Biological Knee Replacement
The most common reason to consider a biological knee replacement is joint degeneration in a young patient where you want to avoid an artificial joint. This may happen in:
- Post-traumatic arthritis
- Severe knee injury
- Knee deformity with loss of cartilage and pain
- Disorders that trigger abnormal bone growth
Your physician may advise biological knee replacement when these indications result in:
- Severe knee pain, swelling, and stiffness that limits your daily activities (such as walking, getting up from a chair, or climbing stairs)
- Moderate-to-severe pain that interferes with your quality of life and sleep
- Chronic knee pain that is not relieved with rest, medications, injections, physical therapy, or other conservative treatments
- You are feeling depressed because of the pain and lack of mobility
- You cannot have a normal work or social life
What happens in a Biological Knee Replacement
Biological knee replacement is performed under anaesthesia either through an open surgery or arthroscopically. Your surgeon will discuss the options with you to determine which approach is best for you.
In general, the procedure involves both a meniscal transplantation and restoration of articular cartilage.
In meniscal transplantation, the damaged meniscal tissue in the knee is first removed. A fresh-frozen meniscal allograft, preoperatively sized to your knee, is then implanted into the knee under the guidance of an arthroscope (a thin, flexible fibre-optic lighted instrument attached with a camera). Bone tunnels or bone troughs are utilised to anchor the bony attachments, and sutures are then placed to the native meniscal rim or capsule.
A paste graft is a surgical technique for articular cartilage restoration that uses your own tissue, such as bone marrow and cartilage from your intercondylar notch to form a paste that is impacted into the defected area of your knee to regrow new articular cartilage. The mixture of articular cartilage and cancellous bone appears to provide a supportive matrix for cartilage formation, providing a smooth cartilage surface in the joint.
Benefits of Biological Knee Replacement
Some of the benefits of a biological knee replacement include:
- Improved pain
- Improved mobility
- Improved joint function
- Improved quality of life
Risks and Complications of a Biological Knee Replacement
As with any surgery, some of the potential complications involved with a biological knee replacement include:
- Bleeding
- Infection
- Pain
- Damage to blood vessels and nerves
- Blood clots or deep venous thrombosis (DVT)
- Stiffness or instability in the knee
- Anaesthetic complications
