Assessment of correlation between knee notch width index and the three-dimensional notch volume

This study was done to determine whether there is a correlation between the notch volume and the notch width index (NWI) as measured on the three most frequently used radiographic views: the Holmblad 45°, Holmblad 70°, and Rosenberg view. The notch volume of 20 cadaveric knees was measured using Computed Tomography (CT). The Holmblad 45°, Holmblad 70°, and Rosenberg notch view radiographs were digitally re-created from the CT scans for each specimen, and the NWI was measured by two observers. The Pearson correlation coefficient between the NWI and notch volume was calculated, as well as between the three views. An independent t test was performed to determine the difference in NWI and notch volume between male and female specimens. The reliability for each view was also determined. There was no correlation between the NWI as measured on the Holmblad 45°, Holmblad 70°, or Rosenberg view and the notch volume. All three radiographic views proved reliable, but showed only a moderate correlation with each other. Men had larger notch volumes than women, but there was no difference in NWI. A knee with a small intercondylar notch is often considered an increased risk for ACL rupture. The NWI is a frequently used two-dimensional method to determine notch size. However, in the present study, this index was not positively correlated with the overall volume of the notch. Based on the results of the current study, the authors would advice to use caution when using notch view radiographs in a clinical setting to predict risk of ACL rupture

Risk factors for Anterior Cruciate Ligament injury in skeletally immature patients: analysis of intercondylar notch width using Magnetic Resonance Imaging

The necessity for identification of risk factors for Anterior Cruciate Ligament, ACL injury has challenged many investigators. Many authors have reported lower Notch Width Index, NWI measured on radiographs in patients with midsubstance ACL lesions compared to control groups. Since a narrow intercondylar notch has been implicated as a possible risk factor related to ACL injury we decided to compare NWI measured on MRI scans between age-matched groups with acute ACL injury with those of the normal population. The purpose of this study was to measure intercondylar notch width on MRI scans in an immature population to determine if there was a difference between the population with ACL tears and a control group. We also wanted to assess age as a risk factor in an ACL injury population. We retrospectively analysed the MRI scans of 46 patients with ACL injuries and 44 patients with normal MRI findings who served as a control group for NWI measurements. For the ACL injury group we collected information from medical charts including age at the time of injury, gender, mechanism of injury, type of activity practised at the time of injury and prevalence of meniscal injury. Demographic data of the control group were comparable with those from the study group. We found a statistically significant (p < 0.001) difference in the mean value of the intercondylar notch width between normal knees (0.2691) and the ACL injury population (0.2415). In the ACL injury group we did not find differences in NWI values with regard to gender, involved side, mechanism of injury and type of sport practised at the time of injury. A narrower intercondylar notch was found to be associated with the risk of ACL rupture in an immature population. The young group of athletes with ACL injury needs further study to prospectively assess the risk of knee injuries