Cartilage Transfer Surgery of the Knee

Cartilage is an important tissue in your body. There are several different types of cartilage the body makes, and one of them is the soft cushion in your joints. The cartilage surface of a joint allows for smooth motion. Unfortunately, injuries and arthritis can cause damage to the cartilage of the joint, causing movement to become painful and limited. In the knee joint, people with cartilage damage may have knee pain, swelling, and stiffness.

There are a number of options for patients who have cartilage damage in the knee joint.  Typically people will try simple, noninvasive treatments to began. If these treatments are not effective, more invasive treatments, including surgical options, can be considered. One of those options in people who have smaller, more isolated areas of cartilage damage is called a cartilage transfer surgery.

A cartilage transfer procedure is a surgery that uses healthy cartilage from a normal area of the knee, and moves the healthy cartilage to a damaged area of the knee. The two types of cartilage transfer procedures are called:

• Mosaicplasty: A mosaicplasty moves round 'plugs' of cartilage and underlying bone to damaged areas. The plugs are each a few millimeters in diameter, and when multiple plugs are moved into a damaged area the result is a mosaic appearance--the multiple small plugs of cartilage look like mosaic tiles.
• OATS: OATS stands for 'osteochondral autograft transfer system,' and the technique is very similar to mosaicplasty. In the OATS procedure the plugs are usually larger, and therefore only one or two plugs are needed to fill the area of cartilage damage. Because of this it does not take on the mosaic appearance, but the principle is the same.

The cartilage plugs are taken from areas of the knee that are non-weight-bearing areas. The hope is that the body will not miss this cartilage and it can be used where it is needed. Over time the holes left from where the plugs are taken will fill with bone and scar tissue.

The cartilage transfer procedure usually begins with an arthroscopic inspection of the knee. If there is an area of cartilage damage that is suitable to cartilage transfer, then the arthroscope is removed and an incision is made.

1. The first step is to prepare the area of damaged cartilage. A coring tool is used to make a perfectly round hole in the bone in the area of damage. This hole is sized to fit the plug.
2. The next step is to 'harvest' the plug of normal cartilage. The plug is taken with the underlying bone to fit into the hole that was prepared in the area of damage. The plug is just slightly larger than the hole so it will fit snugly into position.
3. The final step is to implant the harvested plugs into the hole that was created in the damaged area. Over time, the hope is that the implanted bone and cartilage will incorporate into its new environment.

Cartilage transfer surgical procedures are performed as an arthroscopic knee surgery. The surgical procedures are done in an operating room, but there is no overnight stay in the hospital. The surgery can be done either under general anesthesia, or a regional nerve block.

After surgery, he will likely be placed into a brace, and he will be given crutches or a walker to prevent you from having to place weight on the affected leg. Specific recovery protocols will vary depending on both your surgeon's preference, and the specific location of the cartilage transfer procedure. Generally the early phases of recovery focus on preventing weight from being placed on the joint, and beginning early, protected range of motion activities. Once your surgeon feels that it is safe to place weight on the joint, your will gradually increase the amount of weightbearing on the affected extremity.

A typical recovery following cartilage transfer surgery takes approximately 6-9 months. The first few months are the most arduous in terms of rehab and recovery, but most surgeons will not allow any competitive sports activities until at least 6 months after surgery, if not longer. It is important before considering resumption of any athletic activities but you have regained full mobility and have normal strength in the extremity.

There are risks associated with cartilage transfer surgical procedures. Normal risks of knee arthroscopy include things like infection and blood clot. These are uncommon problems, but when they do occur they can be serious problems. Following your surgeon's instructions can help prevent risks of infection and blood clot. Risks specific to cartilage transfer surgery include the possibility that the transfer cartilage does not remain healthy. Emphasis on meticulous surgical technique by an experienced surgeon who performs this procedure frequently can help area and in addition, following the postoperative instructions and precautions is imperative in order to achieve a successful outcome. Another possible complication is pain at the site where the donor cartilage was obtained. Your surgeon will try to only obtain cartilage from areas where your knee does not need protection. However, some people report donor site pain where the cartilage graft was obtained.

Cartilage transfer surgery is a possible treatment option for people who have smaller, contained areas of cartilage damage within the knee joint. This same surgical procedure has also been performed in other joints, but it is by far most common in the knee joint. People who have more widespread arthritis are not candidates for a cartilage transfer procedure. Successful outcomes from cartilage transfer surgery are most dependent on careful surgical technique, and compliance with postoperative restrictions.