As children participate more often in sports and athletic competitions, more children are developing anterior cruciate ligament (ACL) injuries, a knee injury that used to be thought of as only occurring in children if their bones were not mature. Now, surgeons are performing more ACL repairs on children as before, yet they only have the adult guide to use for their landmarks in doing the intricate repair.
It has become known that if a surgeon is more familiar with the anatomy of the femoral intercondylar notch, a notch in the femur, or thigh bone, that they would be able to reduce the incidence of technical errors and increase the incidence of successful surgeries. The authors of this study used a collection of preserved skeletons to examine and characterize surgical landmarks, such as the notch and the resident’s ridge, raised bony landmark just in front of where the femur is attached to the ACL. The ACL begins between these two landmarks.
The researchers obtained 103 femurs of skeletons that were between three and 20 years old at death. One hundred and one were used for the final results. The researchers divided the group into subgroups of ages three to six, seven to nine, 10 to 12, 13 to 15, and 16 to 20 years of age.
Following the tests and measurements, the researchers found that of the 101 bones, “75 had a well-defined resident’s ridge and 26 had a subtle resident’s ridge.” They found that the older bones were more likely to have a more prominent ridge than the younger ones, those under the age of 12. The researchers also looked at the amount of space that would be available to drill in order to do the ACL repair. They found the average space between the “over-the-top” position, which is right behind the notch, and the resident’s ridge became longer as the skeletons were older; they also changed position slightly.
These are important findings because of the increasing number of ACL repairs being performed on children of all ages. Previous studies had looked at the skeletal make up of children but they were either performed on bones that had already been sectioned or cut, or they used imaging techniques. The magnetic resonance imaging (MRI) was useful, but still not hands on. The authors of this study note that their findings of the space available for drilling (the distance) allows surgeons to understand the importance of where to drill so as not to cause damage.
When studying the skeletons, the authors also looked at the female and male aspects of the structure because of the reported higher incidence of girls sustaining ACL injuries over boys. Their findings were that there was a difference in skeletal distance between the boys and girls.
The authors point out the limitations of their study, which include the limited number of bones from the seven to 15 years age group and that the bones were from the early twentieth century, when children may have been shorter than now and may also have had some metabolic disorders that children today don’t have.
In conclusion, the authors state that the study provides valuable information for surgeons to locate where they should drill if performing ACL repair on a child or adolescent, as well as the differences between boys and girls.