Many patients want to know if we can grow cartilage and replace what has worn out or been damaged. The answer is yes. There are surgical techniques to stimulate the body to build cartilage in certain types of small lesions. These can be performed using a procedure called arthroscopy (described below) through two small incisions.
One procedure to stimulate cartilage production is called a microfracture. During a microfracture, small holes are placed in the exposed bone. The patient's own cells then travel from inside the bone to the surface through these holes. Those cells can then create a cartilage layer and fill the defect.
Osteochondral Autograft Transfer (OATS)
Another procedure is called an osteochondral autograft transfer (OATS). In this procedure cartilage is taken from one place in the knee and transferred to another. The place it is taken from is called the donor site. The donor site is typically a nonweightbearing area.
Autologous Chondroycte Implantation (ACI)
If the chondral (cartilage) lesions are large enough, some patients require an autologous chondroycte implantation (ACI). This is a two-stage procedure. During the first stage, a tiny biopsy of articular cartilage (the cartilage that lines the joint) is taken by using an instrument known as an arthroscope. The cartilage is then sent to a laboratory. In the laboratory the cartilage cells (chondrocytes) are isolated and grown. When the cells have multiplied they are then placed back into the knee in the cartilage lesion. These cells will then build new cartilage.
Osteochondral Allograft Transfer
If the lesion is large and has missing bone, then sometimes a large osteochondral allograft (cadaver bone with cartilage) is required. In this procedure, an X-ray, MRI, or CT scan is taken to determine the exact size of the bone and cartilage defect. Those measurements are then sent to the bone bank. When a donor with the correct size match is found, they contact us. We then perform a transplant procedure. Please note that the transplant must occur within a specified time frame, which means that you will need to be available on relatively short notice.
The techniques above address the covering (cartilage) of the bone. Our understanding of arthritis tells us that the pain often comes from the exposed bone. Since the bone doesn't have any cartilage (shock absorber) covering it, the exposed area has too much stress. That stress can cause changes in the bone (stress fracture, microfracture, bone contusion, insufficiency fracture). Through a technique called Subchondroplasty, we can also address the changes in the bone. In this technique a fluoroscope (live X-ray) is used to guide a small drill into the affected area of the bone. Then special bone filler is injected. The bone filler provides structural support to the bone and allows the body to gradually rebuild the area on its own.
This procedure is sometimes indicated when one area of a joint is affected. It involves cutting the bone and realigning it. In doing so, the weight can be transferred through the unaffected side of the joint. This has the potential to make a joint less painful or more stable.