WHAT IS AN ARTICULAR CARTILAGE INJURY AND HOW IS IT TREATED?
By Steve A. Mora, MD
Orange County Orthopedic Surgeon Specializing in Sportsmedicine
Articular cartilage tears, aka chondral defects are injuries to the joint surface or lining. These lesions occur in similar fashion as a meniscus tear. The younger the patient the more likely the lesion is isolated and discrete. The older the patient, the more likely the lesion is degenerative and diffuse (degenerative joint disease). Some chondral lesions occur without a known reason such as a Osteochondritis dissecans (OCD). Most of the time chondral lesions are associated with ACL tears. Actually, most of the time a chondral lesion is identified at the time of meniscus tear surgery. In these situations the surgeon has to have a game plan for treatment of the surprise tears. Not all chondral lesions are symptomatic, that is, not all of them cause pain. For this reason it is critical for the surgeon to understand the location of your pain. For example if you have medial pain from a medial meniscus tear but a lateral chondral defect is noted at time of surgery. It is quite possible the surgeon may elect to leave the lesion alone.
Chondral, aka, Articular Cartilage Defects: HOW ARE CARTILAGE TEARS TREATED: Are initially treated using arthroscopic methods, done as outpatient, and require general anesthesia. Remember that oftentimes these lesions are not discovered until the time of the surgery for a meniscus tear. It would not be right to ignore these lesions if there is a possibility they are generating some or all the pain. The treatment option depends on the depth and diameter of the lesion.
For all Partial thickness Chondral lesions (grade III and below): Treated with debridement or simple chondroplasty. This means the rough surfaces and edges are shaved and smoothed out.
For Full thickness Chondral lesions, those lesions which have eroded completely down to bone (grade IV) other options can be considered. These options are available for chondral lesion which have failed simple chondroplasty or debridement.
What is Microfracture Chondroplasty?- This is usually the first line of cartilage repair for Grade IV defects or for those which have already undergone simple debridement as mentioned above. A small pick-type tool (awl) is used to make perforations or pick holes in the bone within the center of the lesion. These holes allow blood from the marrow to come in and fill the defect. With time the marrow blood will firm up and become a type of repair cartilage which will cover the bone. In approximately 80% of these cartilage defects there is a good degree of repair cartilage formation which should lead to less pain. The major downside: crutches and motion machine (CPM) for 6 weeks as the repair cartilage forms. No running for 6 months. Possibility of incomplete pain relief (failed repair).
How are chondral tears treated further? If we find a full thickness defect that is very large or one that has not healed with Microfracture, secondary methods of repair can be done at a later date. These include:
What is Osteochondral grafting (OATS) I take small plugs of bone and cartilage from a less critical area of the knee and transfers them to the injury site. Its like a hair plug for men procedure in the knee. Sometimes it requires a 2-3 inch incision. Also requires 6 wks crutches, CPM and no running sports for 6 months. The plugs can also be taken from a cadaver knee. This graft would be called Fresh Allograft Osteochondral transfer.
What is Autologous Chondrocyte Implantation (ACI) or Genzyme: Some may ask what, is a Cartilage cell transplant procedure. A relatively new technique of repair that takes a biopsy (small specimen) of your articular cartilage at the time of your initial knee arthroscopy. It is sent to a lab and “cloned” to create millions of chondrocytes (the cells that make articular cartilage). Once the right number of cells are grown (12 million), I would do a second surgery and transfer the cells into the full thickness chondral defect. Essentially you have to have 2 surgeries, one to harvest the sample and the other to implant the cells. Only physicians trained and certified in this technique are able to provide this option. This technique has been used to resurface large defects, greater than 2cm diameter, and has been proven to work well for very specific cases. Not everyone is a candidate for this surgery. The defect has to be isolated and not the arthritic type. Chondral lesions of the patella and trochlea do not do as well. This is a big surgery with potential side effects or complications. The chance of having going back to professional sports is no excellent. It requires 12 weeks of crutches and no sports for 12 months. Is Genzyme a good procedure? It is a good option for a young patient with major symptoms stemming from an isolated chondral defect which has not responded to microfracture and who do not mind no playing for 9-12 months. Patients with lateral femoral condyle defects usually do best. Those with patella or trochlea defects have about an 80% chance of doing really well. A study called the STAR study showed that up to 50% of patients who had a Genzyme procedure required a second simple knee scope.
Advances in cartilage tear treatment: If you do some web research you will find a plethora of information regarding chondral lesion treatment. These are usually very complex or semi experimental. For example a Tibial tubercle osteotomy is an option for severe patella chondral lesions. I have done these in highly specif situations with good results. I usually do a tibial tubercle osteotomy in conjunction with a cartilage transplant procedure (Genzyme). There is also allograft meniscus (cadaver tissue) transplant for young patients whom have had massive meniscus tears already treated with meniscectomy and who have late onset pain. I also perform meniscus allograft procedure out of my office in Orange. It is usually reserved for the rare young patient with total loss of meniscus. There is Partial knee replacement for single compartment degenerative chondral defects. I do these in our older population who are not good candidates for cartilage transplant (Genzyme). I also perform Fresh allograft transplantation are procedures I do for chondral defects with deep bone loss. These procedures are very good for OCD or massive traumatic osteochondral defects. This is a highly complex procedure but still a good option in special cases.
Cartilage Procedure I do NOT do: There are also metallic caps that are being inserted into the knee to provide a metal surface. These metal implants do not have a strong track record and are questionable in regards to success. There is a company trying to introduce a synthetic meniscus. There is a company offering morselized baby cartilage which can be made into a putty and pressed into the defect (Denovo). There is no proof at all that this is an effective treatment. There are also studies underway using morselized articular autograft (CAIS).
Thank you for your time.
Steve A. Mora, MD
Board Certified Orthopedic Surgeon Specializing in Knee Surgery, Orange, Ca
Please contact me with questions at http://myorthodoc.com/physicians/stevemoramd.html
Dr. Mora is a Board Certified Orthopedic Surgeon practicing in OC Orange County. He can be reached through his webpage above. Call 714 639-3750 for a comprehensive consultation.