Robert Rinaldi, DPM
Posted August 6th, 2010
This tongue-twister of a moniker is often referred to as osteochondritis dessecans, which isn’t a whole easier to pronounce. The lesions can be simply described as small tears in the articular cartilage surfaces of bones. These tears commonly are problematic in the foot when they occur in the ankle, on the talar dome, and on the head of the first metatarsal. Trauma is thought to be the cause, and the lesions result in lasting pain and continued destruction of the joint, with arthritic changes. The joint’s ability to function with smooth motion becomes impaired. The injury is progressive, and often missed at the earliest stages.
OSTEOCHONDRAL INJURY CLASSIFICATIONS
Stage One—In the ankle, joint compression or overexertion with rotation, as with a sprained or twisted ankle, can result in osteochondral lesions. When x-ray is negative for injury to the talar dome, but pain and stiffness persist in the ankle joint long after the incident, an MRI should be ordered, because cartilage is not visible on plain film x-ray.
I feel that initial x-ray exams for ankle sprains should always include stressed views. The stress view can give an indication as to the severity of the ankle sprain and this may include talar dome cartilage tearing. (Please refer to an earlier article, Lateral Ankle Sprain and Chronic Ankle Instability, now available online at www.vtsports.com/articles/lateral-ankle-sprain-and-chronic-ankle-instabi…). When the MRI demonstrates a shallow compression-type lesion with sub-chondral edema of the talar dome, aggressive but conservative treatment is often successful. Non-weight bearing for four to five weeks followed by physical therapy that emphasizes gradual return to full weight bearing status works well. Aquatic PT is fantastic with these injuries, and the athlete can get a cardio workout with a swim that excludes kicking.
Stage Two—These injuries are similar to Stage One, however, x-ray
exams may show some boney defect, and the symptoms will often include a feeling of a catching or momentary locking of the joint. Arthroscopy may be necessary to successfully treat this problem, but conservative treatment should be attempted with non-weight bearing and PT.
Stage Three—At this level, cartilage injury to the talar dome consists of a completely detached fragment that is not displaced.
Stage Four—This is similar to Stage Three, except the fragment is displaced and loose, leaving the bone denuded of cartilage and a crater remains. The Stage Two and Three osteochondral lesion usually will be seen with repeated ankle sprains or frank ankle instability. These talar dome osteochondral lesion classifications are called the Berndt and Harty Classifications. Early diagnosis and treatment of the talar dome injury is important to ensure the best possible outcome.
Osteochondritis Dissecans is common in the knee, ankle, and in the head of the first metatarsal. Over rotation or extreme pressure and trauma caused by hyper-extension of these joints may be the most common cause of cartilage damage. Pain is the common symptom.
The head of the first metatarsal does not have an injury classification and for this reason the problem is often overlooked or treatment is delayed. The result is no less dramatic: pain with motion, an inability to move the joint comfortably, progressive joint arthritic changes, and destruction. X-ray findings usually offer little help in making an early diagnosis. The primary causes are direct trauma as in a heavy object falling onto the joint or the foot slipping, creating exaggerated motion of the joint beyond it’s normal limits. The end result is cartilage damage and progressive destruction of the joint with the formation of a boney spur on the dorsal surface of the head of the metatarsal. This spur further limits the range of motion of the joint, and continued trauma persists with each step. This condition is called Hallux Limitus, and it will progress to Hallux Ridigus. As with the talar dome injury in the ankle, early detection is necessary for the best treatment outcome. Do not overlook an injury to either joint.
A clinical exam followed by appropriate x-rays are the cornerstones to early diagnosis and necessary treatment. The athlete all too often fails to bring these problems to a sports medicine provider. If you have suffered a trauma to a joint, by over extension, twisting, repeated sprains, or by direct insult from a falling object, and the result is pain, begin initial treatment at home with RICE—rest-ice-compression-elevation. Using acetomenaphine or over-the-counter non-steroidal medications could be added to the initial treatment, but if pain with ambulation persists or does not seem to begin abating within 48 hours, I recommend calling for an appointment with your sports medicine specialist.
Not too long ago, treatment was often overlooked because diagnosis was limited by a lack of technology. Once the MRI became readily available, damaged cartilage has become visible. Recognition and classification of cartilage damage in the smaller ankle joint began to follow the same route as with the larger knee joint. As the arthroscope became smaller, it became possible to bring minimally invasive surgical treatment to the ankle. Ankle arthroscopy is common, and it is successful in saving the ankle from progressive, irreversible, disabling arthritis. Though the MRI can be helpful in determining injury to the first metatarsal, it is not considered as important, because early arthroscopic surgery is not yet available.
On the horizon is stem cell implantation to damaged cartilage tissue. Regeneration of cartilage tissue is possible, and though not common, is being done in some areas of the country.
Robert Rinaldi is a board-certified podiatrist and podiatric surgeon at the Gifford Medical Center in Randolph, VT. He is a fellow and a founding member of the American Academy of Podiatric Sports Medicine, and a podiatric consultant to the Dartmouth College track and cross-country teams. He is a former nationally ranked long-distance runner, having competed in 25 world-class marathons. You can reach him at Gifford Sports Medicine and Surgery Clinics in Randolph, VT, or at the Sharon Health Clinic in Sharon, VT, 802-728-2490 or 802-763-8000 or at firstname.lastname@example.org.