Cartilage doesn't grow on trees: cartilage replacement therapy
If you sound like a one-man band when walking down the street, you probably need knee cartilage replacement surgery. That crackling sound you are hearing coming from your knee-joint is the broken cartilage in your knee. It likely has been worn away due to your overweight, a sports injury, or just the normal wear and tear of life.
On the cutting edge of caring for your cartilage is surgery that can actually replace and regrow this cartilage. Surgery can help repair any trauma that may have occurred to the cartilage or help reverse some of the smaller effects of aging. New strides are constantly made in stem cell and cartilage replacement therapy so that in the future even large bands of cartilage might be replaceable.
Cushion for the pushing: cartilage in your knee
Cartilage is the smooth, white tissue that covers the ends of long bones and protects the joint where it comes together. The inside of the joint is covered by a smooth film known as hyaline cartilage. Due to injury or wear and tear, the cartilage can become rough and cause pain on movement. Cartilage replacement therapy aims to regrow this tough material. Most cartilage replacement therapy is performed on the knee, but it can also be performed on the ankle or shoulder. Although many are hoping that the surgery could be a replacement for total knee replacement surgery, this technology is only useful in patients who have small lesions in their cartilage or limited damage due to trauma. It is not particularly helpful for the long-term, widespread effects that are consistent with osteoarthritis.
Autologous chondrocyte implantation: growing some cartilage
Autologous chondrocyte implantation surgery is a two-step cutting edge surgery designed to grow new hyaline cartilage in the knee-joint. The first step in this journey is to have arthroscopic knee surgery on the affected knee to determine if the cartilage is acceptable for this new procedure. If the wear is not extensive, the process of harvesting chondrocytes, or cartilage cells, is performed. The cells are then sent to a lab, and in 4 to 6 weeks, a colony of cells is grown from the harvested cells. Once there are enough cartilage cells, the second surgery is scheduled. This surgery is performed with a large incision over the shinbone. Part of the periosteum, or thick tissue covering the bone, is harvested from the shinbone. It is made into a patch and placed into the defect where the cartilage is to be grown. This patch is made watertight, and the new cells are injected underneath it. The cells then grow underneath the patch and replace the damaged hyaline cartilage.
After the fact: what to expect after growing cartilage
Since this surgery so cutting edge, there have been variable levels of success with it. One problem with the surgery, is that scar tissue forms around patch and further surgery is needed to remove it. This further surgery is usually done with the arthroscope, requiring less invasive measures. Of course, the hyaline cartilage cells themselves can fail to take and the defect will remain. Infection and knee stiffness are other side effects noted with the surgery. After this surgery, it will be very important for you to respect all weight-bearing restrictions your doctor imposes on you. This is the select bearing weight on the implant will cause the new cells to fail. Weight-bearing is usually restricted for 6 to 8 weeks after surgery. Your range of motion, or the ability to move your knee through its entire flexion, might also be restricted after the surgery to aid in implanting the new cells. Depending on where the cartilage defect is located, range of motion restriction may be indicated. If it is in the kneecap area, your range of motion may be severely limited for several weeks. However, defects in other areas of the joint require early range of motion exercises to stimulate cartilage growth. It is important to follow all your doctor's and physical therapist's advice strictly to recover fully and give your cartilage the best chance of growing.
- American Academy of Orthopedic Surgeons; Articular Cartilage Restoration; February 2009
- About.com; ACI – Autologous Chondrocyte Implantation; Jonathan Cluett; November 2011.
- About.com; ACI Rehabilitation; Jonathan Cluett; November 2011.
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