Cartilage Restorative Procedures

The human body withstands tremendous amount of trauma as the results of our daily active life. This well-tuned machine can only continue to function efficiently if it constantly repairs itself. However, there are certain structures within the body that are incapable of repairing and replenishing themselves. Articular cartilage (also known as hyaline cartilage) is one of these structures.

Articular cartilage is the tissue that covers the ends of the bones within all joints of the body. It is responsible for reducing friction, and providing a smooth and painless gliding surface for the joints. Once articular cartilage is damaged, it is incapable of repairing itself. This results in a coarse, irregular, and abrasive surface that does not function well. Patients often experiences pain, swelling, grinding, cracking and popping within the joint.

Treatment options include activity modification, controlling swelling with anti-inflammatory medications and icing, and at times physical therapy. If symptoms persist, then surgical options are available. The surgical option chosen is based on the size, location, and extent of cartilage loss.

Arthroscopic Chondroplasty

Chondroplasty is the medical term used for smoothing over the irregular and loose edges of cartilage. This provides smoother transition between the damaged and healthy cartilage resulting in better gliding surfaces. Although chondroplasty is successful in reducing pain, swelling, clicking, and catching, it does not replace the damaged cartilage with new healthy cartilage. Chondroplasty is best reserved for patients with small, isolated, partial thickness injury (damage cartilage is not deep enough to see the bone). Recovery is fast and procedure is done arthroscopically with minimal pain and early return to pre-injury level of activity.

Microfracture Chondroplasty

Microfracture chondroplasty is a relatively new procedure that allows growth of cartilage in the injured joint. Lack of blood supply to the area of articular cartilage injury is at least partially responsible for inability of the articular cartilage to repair itself. Microfracture chondroplasty is performed to bring blood supply and fresh new cells. These cells are responsible for new cartilage production. This arthroscopic procedure is performed in patients with lesions that are small than 2 cm2. The size of the lesion is determined by pre-operative MRI and also during arthroscopy. After chondroplasty of the lesion is performed, the exposed bone is drilled with arthroscopic instruments to create small controlled fractures of the bone under the lesion. This provides a good source of blood supply for repair of the cartilage. With early motion of the joint and non-weight bearing for 6-8 weeks, the lesion will be covered with fibrocartilage. Fibrocartilage is different than articular cartilage (hyaline cartilage) in that it is not as durable and does not provide as effective of a gliding surface. However, for properly selected patients, it is an excellent choice to relieve the symptoms of damaged cartilage and return them to their pre-injury function. Patients notice improvement in their pain and function up to 10-12 moths after the operation.

Autologous Chondrocyte Implantation (ACI)

ACI is a new FDA approved procedure for restoring articular cartilage (hyaline cartilage) to the areas of injury. It is reserved for patients with focal lesions in the femur or patella of the knee. However, clinical trials are showing promise in other joints of the body (ankle and shoulder).

ACI is a two-step procedure. First step is to harvest small amount articular cartilage to be sent to laboratory to grow new cells that make articular cartilage (usually take 4-6 weeks to grow the cells). Second step is to implant the grown cells inside the area of defect. The first step is done arthrsocopically and recovery is fast. The second step is done by arthrotomy (opening the joint). Motion is started right away and patients are kept non-weight bearing for 6-8 weeks. The new cells produce articular cartilage and will grow over the defect to create a smooth gliding surface.

ACI is the only known procedure that reproduces articular cartilage after injury. After adequate rehabilitation, patients often return to their normal pre-injury level of function.

ACI is not recommended in patients with diffuse cartilage damage, kissing lesions, unstable knees, mal-aligned knees, or patients with certain allergies. Patients notice improvement in their function up to 18 months after the operation.

The steps for ACI procedure are as follows:


Step 1: Biopsy. Your surgeon takes a tiny piece of healthy cartilage during an arthroscopic procedure. The biopsy contains millions of healthy cartilage cells also known as chondrocytes.

Chondroplasty photo

Step 2: Biopsy Processing and Cell Culturing. The biopsy is sent to Genzyme Tissue Repair in Cambridge, Massachusetts, for processing and culturing. Processing releases the Chondrocytes, which are then cultured or grown for about 5 weeks. The chondrocytes multiply significantly during culturing to about 12 million cells. These cells, Carticel, are returned to your surgeon for implantation.

injury and damaged cartilage

Step 3: An incision is made to expose the injury and damaged cartilage is removed.

watertight compartment

Step 4: Periosteum, a tissue that covers the bone, is harvested from the shinbone and sutured over the injury site to create a watertight compartment.

After ensuring that the injury site is watertight

Step 5: After ensuring that the injury site is watertight, choncrocytes are implanted. Here the cells may continue to multiply forming the building blocks of healthy cartilage and integrate with surrounding cartilage. With time, the cells will mature and fill in the injury site with a firm durable tissue.