In this clinical sports medicine update, orthopedic surgeons from the Hospital for Special Surgery in New York City present current diagnostic and treatment ideas on the topic of osteochondral lesions (OCL) of the ankle. The term osteochondral tell us that the joint cartilage (chondral) and bone (oste) underneath have been damaged.
With some of the more severe osteochondral lesions (OCL), there is a piece of cartilage with the bone attached that is loose in the joint causing further problems. Sometimes these loose fragments are referred to as joint mice. That name refers to the fact that there is a squeaking sound in the ankle joint. This sound occurs as the osteochondral fragments move or rub against other anatomical structures in the joint.
With any overview and update on a topic, the condition is defined, explained, and the etiology (cause) discussed. This article adds a description of the classifiction systems used to describe the severity of the condition. Diagnosis and treatment (both operative and nonoperative) along with results of each type of management approach are included as well. With updated technology, both the diagnostic process and the treatment options for this condition have changed remarkably in the last few years.
Here’s a summary of the information provided in this extensive and detailed article. Ankle sprains are the most common cause of osteochondral lesions. Sports athletes are affected most often. But anyone who injures the ankle or develops bone chips or fragments for any reason can develop debilitating osteochondral lesions.
Besides acute trauma, osteochondral lesions (OCLs) can also occur as a result of vascular diseases, chronic microtrauma, degenerative joint disease, and endocrine or metabolic disorders. Problems with joint alignment is a risk factor for osteochondral lesions no matter what the underlying cause may be. People who develop OCLs in multiple joints and who have a family history of OCLs, may have a hereditary factor that has not been fully defined yet.
The diagnosis is made based on the patient’s history, clinical presentation, and X-ray findings. Imaging studies like CT scans and arthroscopic exam make it possible to determine the size, shape, location, and extent of the cartilage/bone displacement. These characteristics are used to classify the injury. Various classification methods have been proposed. The authors provide a table summarizing eight different schemes reported in the literature based on X-rays, arthroscopy, MRIs, and CT scans.
Most people who are diagnosed with osteochondral lesions report ankle pain, swelling, stiffness, and weakness. There is often a history of repeated jumping, prolonged running, or other high impact activities. Many of the athletes describe frequent episodes of the ankle giving out from underneath them. This is a sign of ankle instability.
Once the condition has been accurately diagnosed, what can be done about it? Well, treatment depends on the results of the classification process. Some of the milder lesions that have not been displaced (damaged pieces have not pulled away from the bone or moved into the joint) can be managed conservatively (without surgery). Children especially seem able to heal with a short period of rest, the use of antiinflammatory medications, and ankle immobilization in a cast, splint, or brace. Spontaneous healing is less likely in adults who tend to get better results with surgery.
Surgery to remove or replace the loose fragment seems to have the best success in adults. This particular area of the anatomy (cartilage) doesn’t have a very good blood supply, so healing with new tissue doesn’t happen unless the defect is so deep the bone marrow is exposed. Nondisplaced pieces can be fixed in place with pins.
For more severe damage, the surgeon can use arthroscopic surgery combined with computer-assisted techniques to fill in the defect with bone graft material or even the newer bone graft substitute products available. Other techniques such as microfracture (drilling tiny holes around the defect) are designed to stimulate the production of fibrocartilage at the site of the lesion.
Depending on the location of the osteochondral lesion, it might be possible to graft plugs of bone into the ankle defect. The bone plugs are taken from a nonweight-bearing spot in the patient’s knee joint. This is called autologous tissue transplantation or mosaicplasty.
More extensive, open-incision surgery may be needed for large or deep osteochondral lesions. The damaged area is debrided (cleaned and smoothed) before bone graft material (usually from a donor) is transplanted to the opening left after debridement. The area is packed with graft material and held in place with a screw.
An alternative treatment to bone grafting is a procedure called autologous chondrocyte implantation/transplantation (ACI/ACT). This is a two-step operation where the surgeon first harvests normal, healthy chondrocytes (cartilage cells) from the patient and transfers them to a lab. In the lab, the cells are reproduced for a period of four weeks until there are enough cells to transfer back into the defect (the second step in the procedure). The multiplied chondrocytes are sealed in place with a special fibrin glue.
Although these various techniques can work well, there are still a lot of unknowns about when to use each one, which patients are the best candidates for each procedure, and how long the graft will last. Researchers are continuing to look for easier, less expensive, and more effective ways to treat osteochondral lesions.
One of the techniques under investigation is called viscosupplementation therapy. This is the injection of a hyaluronic acid into the joint. This treatment approach has been used in arthritic knees to preserve and protect cartilage while stimulating new cartilage growth. Preliminary results suggest this might be a safe and effective way to treat osteochondral lesions (OCLs) and maybe even prevent ankle arthritis from developing later as a result of this injury. Using it along with cartilage graft techniques might help preserve the graft as well.
Other new techniques using electrical or electromagnetic stimulation, ultrasound, stem cell transplants, and platelet-rich plasma are also under consideration as potential management techniques for OCLs. Most of these approaches are being used in animal studies right now. Scientists are exploring the mechanisms by which each of these methods work to stimulate new cartilage growth. And research continues to expand now including experimentation with growth factors and gene therapy as a way to promote optimal healing. Again, these studies remain in the early stages using animals as subjects before trying these ideas on humans.
The crystal ball isn’t entirely clear but some experts predict that traditional orthopedic surgery for OCLs will give way to robot-assisted and computer-navigation surgery. These techniques make it possible to perform minimally invasive procedures that reach right into the exact spot in need of treatment. The increased accuracy of placement of graft materials may result in better outcomes for the patient.
Osteochondral lesions are becoming more common as more and more people of all ages participate in sports activities. Finding more effective ways to treat this problem will continue to be the focus of research and debate. Studies are needed to provide evidence as to which procedures work best for patients based on factors such as age, severity of injury, and activity level.