As more and more children and teens participate in organized sports at a younger age, it is no surprise that knee injuries are on the rise. In this report, a pediatric orthopedic surgeon from UCLA School of Medicine reviews four specific injuries that may require surgical intervention. These include: 1) anterior cruciate ligament (ACL) injury, 2) symptomatic discoid lateral meniscus, 3) juvenile osteochondritis dissecans, and 4) traumatic patellofemoral instability.
The injuries themselves are unique in that they affect a knee that is not skeletally mature. Prevention of long-term complications such as stiffness and growth arrest must be addressed during treatment. Given these two concerns, the author focuses on what’s new in the surgical treatment of these four conditions.
Let’s take a brief look at each of these four knee injuries in the youth athlete. In youths, anterior cruciate ligament ACL injuries can create knee joint instability, damage to the meniscus (knee cartilage), and chondral injury (damage to the bone). When the ACL is torn during pivoting activities of the leg in this age group, two things can happen.
First, the place where the growth plate and bone meet (called the condroepiphyseal attachment) is damaged. This, in turn, can cause a fracture of the tibial spine (place where the ACL attaches to the bone). And like all fractures, the bone can be separated and displaced (shifted).
Repairing this type of fracture without further injuring the growth plate is a challenge. Many different surgical approaches (e.g., transphyseal soft tissue ACL reconstruction, extraphyseal ACL reconstruction with iliotibial band graft) have been tried and reported on with varying degrees of success. So far, there isn’t one best way to surgically repair this problem. More study is needed as all reports so far are just case series with a small number of patients with a short period of follow-up.
Next, injury to the discoid lateral meniscus is only treated when there are painful symptoms with snapping or clunking of the knee and/or loss of full knee extension. Children affected most often by this type of injury are usually under the age of 10. As with adults, the current thinking on this injury is NOT to remove the torn cartilage. Instead, the tissue is repaired as much as possible in order to prevent arthritic changes later.
Juvenile osteochondritis dissecans (OCD) is our third condition of interest. OCD is a problem that affects the knee at the end of the big bone of the thigh (the femur). The area of bone just under the cartilage surface is injured, leading to damage to the blood vessels of the bone. Without blood flow, the area of damaged bone actually dies. This area of dead bone is referred to as the osteochondritis lesion.
Treatment of OCD can be nonsurgical with immobilization and change in activity until healing is seen on X-rays. When healing doesn’t occur, the surgeon can drill tiny holes in the joint surface to cause bleeding and stimulate healing. If the joint cartilage is broken off with a bit of bone still attached, it may be necessary to reattach the fragment or remove it and fill in the hole left behind. Treatment really depends on the patient’s age and skeletal maturity, how long the condition has been present, and how stable (or unstable) the lesion is.
And finally, the last of our four knee disorders: traumatic patellofemoral instability. This refers to a chronically dislocating knee cap. Most of the youths who suffer this problem have some type of anatomic abnormality that puts them at risk for this condition. Most of these cases have to be treated conservatively without surgery because a good method of surgical repair has not been discovered yet. Techniques for successful reconstruction of ligaments around the knee cap are being investigated.
In summary, this article provides orthopedic surgeons and sports physicians an opportunity to review four injuries to the skeletally immature knee. Treatment is focused on surgery, surgical techniques, and the outcomes for each one. Anyone treating young athletes will find this information of interest, especially now with community sports involvement and subsequent knee injuries at a peak.