Cruciate ligament rupture and the role of radiological knee shape

Patients with an anterior cruciate ligament (ACL) rupture or a posterior cruciate ligament (PCL) rupture, have a significant health burden; both for the patients themselves, and for the general health system. With significant, short and long-term consequences. Loss of
mobility, loss of sports activity, increased risk of early osteoarthritis, and not returning to their pre-injury sports capability are just some of the consequences. Therefore, preventing cruciate ligament (CL) ruptures is both in the interest of patients, and in the interest of the general health care systems. To prevent CL ruptures, risk factors need to be identified. The overall aim of this thesis is to find risk factors related to the shape of the knee, which can be used to select patients at risk for a CL rupture. 

In chapter 2 we compared the lateral and Rosenberg view X-rays of 168 prospectively followed patients with a ruptured ACL to a control group with intact ACLs, matched for gender, after knee trauma. We used statistical shape modeling software to examine knee shape and find differences in shape variants between both groups. In the Rosenberg view X-rays, we found five shape variants to be significantly different between patients with an ACL rupture and patients with an intact ACL but with knee trauma. Overall, patients who had ruptured their ACL had smaller, flatter intercondylar notches, a lower lateral tibia plateau, a lower medial spike of the eminence, and a smaller tibial eminence compared to control patients. We concluded that in general, patients with an ACL rupture have smaller intercondylar notches and smaller tibial eminences in comparison to patients with an intact ACL after knee trauma. 

In chapter 3 we retrospectively compared Magnetic resonance imaging (MRI) scans of 121 patients with a proven ACL rupture to 92 control patients with proven intact ACLs and PCLs. Patients were selected for age, weight, height, and sex (by manual selection). We measured the volumes of the intercondylar notch and ACL and PCL, the bicondylar width (BW), the notch width (NW), and the notch width index (NWI). Second, we compared the result between males and females. Patients with an ACL rupture had, on average, a smaller NW (Psmaller volumes of the PCL (Paverage a smaller NW (P(P=.004) and PCL (Psexes (P=0.508). We concluded that a smaller notch dimension, smaller volumes of the intercondylar notch, and smaller volumes of the PCLs are related to the presence of an ACL rupture. Secondary, females have smaller volumes of the intercondylar notch, ACLs and PCLs, but do not have a smaller NWI when compared to males.