Greg Oden of the Portland Trail Blazers Will Miss the Remaining 2010-2011 Season
Portland Trail Blazers center, Greg Oden, is scheduled to undergo microfracture surgery of his left knee on Friday. What is this surgery and why is it performed?
The knee consists of 3 bones: the knee cap (patella), the thigh bone (femur), and the leg bone (tibia). These three bones interact to give range of motion to the knee. Inside the knee joint, the bones are covered with a substance known as cartilage. The cartilage allows the bones to glide together, painlessly. This substance is critical to the function of any joint in the human body. Damage to the cartilage can occur in many different forms, one of which is known as an osteochondral defect (OCD) or osteochondritis dissecans of the knee.
An OCD lesion of the knee can be described as a “pothole” of the joint and cartilage surface. With an OCD lesion, the cartilage is damaged. The bone underneath this cartilage may or may not be damaged as well. OCD lesions can occur in any joint, but most commonly happen in the knee. Typically the femoral side of the knee joint is affected.
The OCD lesion disrupts the smooth surface of the cartilage and makes this uneven. The uneven surface can lead to arthritic of the joint. The cartilage that is damaged may remain partly attached to the bone or may be fully detached from the bone. When the cartilage is fully detached, the piece is at risk of floating throughout the knee and damaging other cartilage areas.
The most common causes of OCD lesion are trauma and disruptions of the blood supply (ischemia).
Not all OCD lesions cause symptoms. Those OCD lesions that cause symptoms can range from pain, swelling in the joint (effusion), locking of the joint, or clicking. The patient may complain of the knee giving out.
In kids, OCD lesions are initially treated with immobilization, in the form of a brace or cast.
If patient fail conservative care or have moderate to severe pain, the goals of treatment are to: decrease pain and swelling, fill in the “pothole”, and minimize the rate of arthritis progression. This can be performed in a number of surgical ways.
Microfracture – In microfracture surgery, an arthroscopy procedure is performed. Two to three incisions are placed into the knee. A camera and tools are placed into the joint to evaluate the knee. The OCD lesion is found and cleaned (debrided). The cartilage is debrided back to a “stable” base, where it no longer lifts off the underlying bone. Holes are then placed into the bone (“pothole”). The goals of these holes are to stimulate bleeding and scar tissue formation. It is hoped that the scar tissue will fill in the “pothole”
Autologous Chondrocyte Implantation – This surgery is usually reserved for the patient who has already failed 1 or 2 surgeries. This surgery requires 2 surgeries. In the first surgery, a small piece of cartilage from the knee or another joint is taken out. The cells/chondrocytes from this cartilage is grown in a lab. Weeks later, in a second surgery, these cells are placed into the OCD lesion.
Mosaicplasty/Osteochondral Autograft Transplantation (OATS) – This surgery is usually reserved for the patient who has already failed 1 o 2 surgeries. This surgery require taking “plugs” of bone and cartilage from one are of the joint and placing these plugs into the OCD lesion. The “plugs” help to fill the OCD lesion.
Allograft Transplantation – In this surgery, bone and cartilage is taken from a “bone bank”, where people have died and donated their bones for medical use. The tissues are sterilized in a variety of ways. The bone and cartilage are then used by the surgeon to fill in the pothole.
Other technologies are evolving to treat these lesions surgically as well.
WHEN TO SEEK MEDICAL CARE
If you suspect that you have symptoms concerning for an OCD lesion, you should seek medical attention. A good physical exam, x-rays, and perhaps a CT scan or MRI may be needed to evaluate the OCD lesion.
RETURN TO ACTIVITIES/OUTCOMES
Most athletes with this injury are out from competitive plays for at least 8 to 10 months. Extensive rehabilitation is needed to optimize the range of motion and strength of the knee.
For a video animation of “Anatomy of the Knee”, please see the “Education” tab of my website. Click orthopaedics, then knee, then conditions, then “Anatomy of the Knee”.
For a video animation of “Microfracture Drilling Procedure”, please see the “Education” tab of my website. Click orthopaedics, then knee, then procedures, then ” Microfracture Drilling Procedure “.
For a video animation of “Autologous Chondrocyte Transplantation”, please see the “Education” tab of my website. Click orthopaedics, then knee, then procedures, then “Autologous Chondrocyte Transplantation”.
For a video animation of “OATS”, please see the “Education” tab of my website. Click orthopaedics, then knee, then procedures, then “OATS”.
I hope that Greg Oden makes a good recovery and that we see him back in the 2011-2012 season.
All material published through this blog/website is for informational and entertainment purposes only. Readers are encouraged to confirm the information contained herein with other sources. Patients and consumers should review the information carefully with their professional health care provider. The information is not intended to replace medical advice offered by physicians. Dr. Parekh and Duke University will not be liable for any direct, indirect, consequential, special, exemplary, or other damages arising from the discussions in this blog.