Correlation between the 2-dimensional notch width and the 3-dimensional notch volume: a cadaveric study.

PURPOSE The purpose of this study was to compare the size of the entrance of the notch, as measured arthroscopically (2-dimensionally), with the volume of the notch as measured by use of computed tomography (CT) (3-dimensionally). METHODS For 20 cadaveric knees, the dimensions of the notch entrance were measured arthroscopically, and the notch volume was measured by use of CT. The correlation between the size of the notch entrance and the notch volume was calculated. Intraobserver reliability and interobserver reliability of the arthroscopic and CT measurements were tested. RESULTS The Pearson correlation coefficients between CT-assessed notch volume and arthroscopically assessed notch height and width at the bottom, middle, and top of the notch were 0.603, 0.506, 0.551, and 0.642, respectively. The intraobserver reliability and interobserver reliability of the arthroscopic measurements were above 0.962 and 0.819, respectively, and 0.983 and 0.975, respectively, for the CT measurements. CONCLUSIONS There were only moderate correlations between arthroscopic notch measurements and notch volume. Both the arthroscopic and CT measurements proved highly reliable. CLINICAL RELEVANCE The moderate correlation between 2-dimensional and 3-dimensional notch measurements warrants caution concerning the use of either measurement for assessing risk for anterior cruciate ligament injury or as justification for notchplasty until studies between the relation of 3-dimensional notch volume and anterior cruciate ligament injury are conducted.