CARTILAGE PROBLEMS

What is articular cartilage?

Articular cartilage is the smooth whitetissue that covers the ends of your bone in your joints. It allows the bones to glide over each other with very little friction.Articular cartilage can be damaged by injury or normal wear and tear. Because cartilage does not heal itself well, there are various surgical techniques to stimulate the growth of new cartilage. Restoring articular cartilage can relieve pain and allow better function. Most important, it can delay or prevent the onset of arthritis.

Cartilage damage 

The main component of the joint surface is a special tissue called hyaline cartilage. When it is damaged, the joint surface may no longer be smooth. Moving bones along a tough, damaged joint surface is difficult and causes pain. Damaged cartilage can also lead to arthritis in the joint. The goal of cartilage restoration procedures is to stimulate new cartilage growth or implant new cartilage in the damaged ar ea — either hyaline cartilage or fibrocartilage (a different and somewhat less durable form of cartilage). In many cases, patients who have joint injuries, such as meniscus tears or ligament tears, will also have cartilage damage. This damage may be hard t o diagnose because hyaline cartilage does not contain calcium and cannot, therefore, be seen on an X - ray. It is best seen on MRI Scan.

Who is eligible?

Most candidates for articular cartilage restoration are young adults with a single injury, or lesion. Older patients, or those with many lesions in one joint, are less likely to benefit from cartilage surgery.  The knee is the most common area for cartilage restoration.

Surgical procedures

Many procedures to restore articular cartilage are done arthroscopically. During arthroscopy , two or three small incisions are made around your joint using an arthroscope.
Some procedures require more direct access to the affected area. Longer, open incisions can be required. Sometimes it is necessary to address other problems in the joint, such as meniscal or ligament tears, when cartilage surgery is done.
In general, recovery from an arthroscopic procedure is quicker and less painful than a traditional, open surgery. Mr. Gohil will discuss the options with you to determine what kind of procedure is right for you.

The most common procedures performed by Mr. Gohil for cartilage restoration are:
•    Microfracture
•    Osteochondral autograft transplantation
•    Matrix-induced autologous chondrocyte implantation
•    Osteochondral allograft transplantation

Microfracture

The goal of microfracture is to stimulate the growth of new articular cartilage by creating a new blood supply.
The procedure can be done with an arthroscope. A sharp tool called an awl is used to make multiple holes in the exposed bone surface, called subchondral bone. This action creates a healing response. New blood supply is able to reach the joint surface, bringing with it new cells that will form the new cartilage.

Microfracture generates fibrocartilage. While not as durable as the normal hyaline cartilage of the joint surface, fibrocartilage can be helpful for repairing smaller lesions (areas of damage).

Osteochondral Autograft Transfer System (OATS Procedure or also known as Mosaicplasty)

In osteochondral autograft transplantation, cartilage is transferred from one part of the joint to another.

The procedure, which can be done with an arthroscope or using an open approach, provides more durable hyaline cartilage to the defect area. A cylinder-shaped plug (graft) of healthy cartilage tissue and underlying bone is taken from an area of the bone that does not carry weight (non-weightbearing area). The graft is then matched to the surface area of the defect and pushed into place. This leaves a smooth cartilage surface in the joint.

A single plug of cartilage may be transferred, or Mr. Gohil may perform a procedure using multiple plugs, called mosaicplasty.

Mosaicplasty type osteochondral autograft transplantation procedure.
Reproduced from Hangody L, Rathonyi GK, Duska Z, et al: Autologous Osteochondral Mosaicplasty. Surgical Technique J Bone Joint Surg Am 2004;86 (suppl 1):65-72.
 
Osteochondral autograft is used for small to medium sized cartilage defects. This is because the healthy graft tissue can be taken only from a limited area of the same joint.
This procedure is also helpful when an MRI reveals that the bone under the cartilage defect shows signs of stress or wear.

                                  Example of a cartilage (Chondral) defect(left image) treated with anosteochondral plug(right image).

Matrix Induced Autologous Chondrocyte Implantation (MACI)

MACI is a two-step procedure in which new cartilage cells are grown and then implanted in the cartilage defect.First, healthy cartilage tissue is removed from a non-weightbearing area of the bone. This step is done as an arthroscopic procedure. The tissue which contains healthy cartilage cells, or chondrocytes, is then sent to the laboratory. The cells are cultured on a collagen matrix (a biologic scaffold) and increase in number over a period of 6 weeks.

An open surgical procedure, or arthrotomy, is then done to implant the newly grown cells onto another collagen matrix, which is secured within the defect using fibrin glue (a biologic adhesive). MACI is most useful for younger patients who have single defects larger than 2 cm in diameter.

Advantages of MACI:

• It provides more durable hyaline cartilage.
• By using the patient's own cells, there is no danger of a patient rejecting the tissue.

Potential disadvantages of MACI:

• It is a two-stage procedure that takes several weeks to complete.
• It requires an open incision.

Matrix Induced Autologous Chondrocyte Implantation (MACI)
MACI is a two-step procedure in which new cartilage cells are grown and then implanted in the cartilage defect.
First, healthy cartilage tissue is removed from a non-weightbearing area of the bone. This step is done as an arthroscopic procedure. The tissue which contains healthy cartilage cells, or chondrocytes, is then sent to the laboratory. The cells are cultured on a collagen matrix (a biologic scaffold) and increase in number over a period of 6 weeks.
An open surgical procedure, or arthrotomy, is then done to implant the newly grown cells onto another collagen matrix, which is secured within the defect using fibrin glue (a biologic adhesive). 
MACI is most useful for younger patients who have single defects larger than 2 cm in diameter.

Advantages of MACI:
•    It provides more durable hyaline cartilage.
•    By using the patient's own cells, there is no danger of a patient rejecting the tissue.

Potential disadvantages of MACI:
•    It is a two-stage procedure that takes several weeks to complete.
•    It requires an open incision.

    
Large cartilage defect on femur in the knee

Cartilage cells implanted on a collagen matrix into the defect with fibrin tissue glue

Osteochondral allograft

If a cartilage defect is too large for an autograft, an allograft may be considered.
Like an autograft, an allograft is a graft composed of cartilage and bone. Allografts, however, are taken from a cadaver donor instead of the patient's own body. In the laboratory, the allograft tissue is sterilized, prepared, and tested for any possible diseases that might be transmitted to the recipient.
An allograft is typically larger than an autograft, but like autografts, allografts provide hyaline cartilage to the defect. The benefit of an allograft is that it can be shaped to fit the exact contour of the defect and then press fit into place.

Allografts are typically done through an open incision.

The allograft needs to be size-matched and there is usually a delay of several weeks until a suitable donor has been found prior to your surgery.