What Is an Osteochondral Grafting of Articular Cartilage Injuries?

Osteochondral grafting treats conditions in which there is cartilage damage and the underlying bone is exposed like arthritis.

Articular cartilage covers the bony ends of the joints throughout the body. Cartilage being smooth allows easy gliding of the joint. Cartilage may be damaged due to injury or degenerative diseases such as arthritis. 

A partial or full-thickness cartilage injury or erosion of the cartilage due to severe arthritis can lead to the exposure of the underlying bone. 

Osteochondral grafting is a method of treating such conditions of cartilage damage where the underlying bone is exposed. The procedure is typically performed for weight-bearing joints such as the knees, but it may be performed for other joints too. The surgery is performed with the goal of restoring knee stability and achieving a pain-free range of motion.

Types of osteochondral grafts 

• Autograft: A cartilage and bone from another site in the knee in the patient’s own body.
• Allograft: A tissue graft is obtained from a donor knee and made to fit the patient knee.

Transplants of autogenous or allogeneic osteochondral grafts have become popular due to the following reasons:

• They offer a possibility of true hyaline cartilage resurfacing.
• They can be performed in a single procedure.
• They are performed with reusable equipment.
• They do not require outside laboratory assistance.
• No screws or other devices are typically required to hold the graft as they fit tightly.
• It is ideal for younger patients and athletes as a replacement to the joint replacement surgery.

The surgery may be contraindicated in the following conditions:

• Serious underlying medical conditions
• Poor nutritional status
• Tumors
• Joint space diseases
• Secondary changes due to cartilage damage in degenerative joint disease
• Limitations to the amount of tissue that can be taken from within a patient’s own knee so larger areas of cartilage loss may not be optimal for this approach
• Global arthrosis (erosions or abnormalities at multiple sites of the joint)
• Older patients with degenerative joint disease, such as osteoarthritis, would benefit more by a joint replacement surgery.

Prior to the surgery, the surgeon performs a complete physical assessment. The surgeon performs blood and radiological assessments such as X-ray and magnetic resonance imaging (MRI) to assess the joint status. 

Fitness for the surgery and consent is obtained. The surgery is performed under general anesthesia.

Because there is a wide range of chondral disease, the surgeon may perform an arthroscopic evaluation for the assessment of a chondral lesion before proceeding to open surgery to perform an osteochondral grafting. 

Arthroscopy is a procedure in which a narrow tube with a camera and light source is inserted through a small incision to diagnose and treat problems inside a joint. Surgical instruments may also be inserted in arthroscopic procedures. This procedure may be performed prior to the surgery or during graft surgery.

Cartilage transplant or an osteochondral autograft or allograft is performed via an open approach

• The defect is exposed via an open incision (a surgical cut). 
• The visible difference between a smooth, healthy cartilage and the defect is identified. 
• After the defect size is confirmed, a drill of matching diameter is used to remove the damaged cartilage and bone segment to prepare the area for a graft. 
• The graft is prepared by cutting it to the size of the defect. The graft is then washed. 
• The graft may be soaked in a bone marrow aspirate concentrate (BMAC) for patients electing to supplement the procedure with stem cells. 
• The osteochondral graft is then fitted into the prepared defect.

After the surgery

The patient may be discharged two to three days after the surgery. Weight bearing is allowed while an immobilizer is worn for the weight-bearing joint, for example, a knee immobilizer. This reduces the contact pressure in the joint. 

The immobilizer may be removed for sedentary activity and range-of-motion exercises during the initial three weeks after the surgery. Complete recovery may take six to eight weeks.

Regular follow-up with the surgeon and physical therapy would be required. The surgeon may perform an arthroscopic evaluation of the joint to monitor healing.

Some complications encountered during the surgery are

• pain, swelling, and bruising,
• bleeding,
• infection,
• an injury to the surrounding nerves and blood vessels and
• graft failure.