Knee Cartilage Injury
Most knee procedures are minimally invasive surgeries performed with an arthroscope (an endoscope for use in joints). Your surgeon will make small incisions around the joint and perform the surgery using slender instruments, including a tiny camera that provides a view inside the area. In general, recovery from an arthroscopic procedure is quicker and less painful compared with recovery from an open (traditional) surgery. However, some procedures do require larger, open incisions, so that the surgeon can have more access to the area.
UCSF offers the following cartilage repair and regeneration procedures:
Microfracture: The surface layer of the bone, called the subchondral bone, is hard and has limited blood flow, so this technique creates small holes in the bone to allow for greater flow. Blood contains bone marrow cells that stimulate cartilage growth and form fibrocartilage, which covers the injured area. Following this arthroscopic procedure, patients must strictly follow the post-op protocol, which includes using crutches and a continuous passive motion (CPM) machine, which gently flexes and extends the knee.
Cell-based cartilage resurfacing: Matrix-induced autologous chondrocyte implantation, or MACI, is a cell-based cartilage resurfacing procedure. For this procedure, some of the patient's cartilage cells are harvested, grown and re-implanted into the area that has damaged cartilage.
The technique requires two operations. In the first, a surgeon arthroscopically removes cartilage cells from areas of the knee joint that don't bear weight. The cells are then made to multiply in a lab and implanted onto a scaffold (material that promotes tissue growth), which will be placed inside the knee. In the second operation, an incision is made to expose the defective cartilage. A bioadhesive, which makes implantation quick and easy, is used to glue the cartilage scaffold onto the knee bones. Over months, the new cartilage matures and integrates with existing cartilage.
Osteochondral autograft transplantation (mosaicplasty): This technique involves transferring healthy cartilage tissue, called a graft, from one part of the knee to the damaged area. The graft is taken as a "plug" of cartilage and underlying bone, and generally harvested from an area that bears minimal weight. A single plug, or multiple plugs, may be transferred. Usually performed in open (traditional) surgery, this procedure can sometimes be done arthroscopically.
Osteochondral allograft: If a cartilage defect is too large to be treated by an autograft, an osteochondral allograft may be required. Cartilage is taken from a cadaver donor, sterilized and prepared for implantation. It can be shaped to fit the exact contour of the patient's cartilage defect. This is an open (traditional) surgery rather than an arthroscopic one.
Meniscus transplant: This procedure is recommended for patients who have lost most of their meniscus or had it removed. The meniscus provides cushioning and stability to the knee. Transplanting the meniscus from a cadaver donor restores these benefits to the knee. Through a small incision, the surgeon can arthroscopically suture the cadaver meniscus to the patient's knee.
After most cartilage repair surgeries, patients are on crutches for six to eight weeks. Some patients will need to use a CPM machine. Closely following the post-op protocol is essential to achieving a good outcome from any of these procedures. A full recovery takes several months.
Seeking care at UCSF Health
UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.