Summary:
INTRODUCTION: The main goal of the Anterior Cruciate Ligament (ACL) Reconstruction is the replacement of the torn ligament usually with a tendon autograft. The autograft should show similar or improved biomechanical properties and to be vascularized in order to restore the compromised knee function.
PURPOSE: The purpose of the present study was to quantitatively analyze the morphometric characteristics of the three tendon grafts most commonly used in the reconstruction of an ACL tear utilizing high resolution Magnetic Resonance Imaging (MRI). The hamstrings tendons (HT: gracilis, semitendinosus), the quadriceps tendon (QT) and patellar tendon (PT) in the same patient were studied.
METHOD: In this study we evaluated 100 consecutive patients, 50 males and 50 females with an acute ACL tear following a sports injury. All patients underwent 3T MRI of the knee with extended field of view. The tendon dimensions were performed using a SPACE isotropic 3D sequence with fat suppression. The selected measurements were performed on planes perpendicular to the tendons with the exception of the PT and QT length were the selected plane was longitudinally oriented. The dependent variables were the length of the PT and the QT, the perimeter, the cross-sectional area (CSA) and the maximum mediolateral and anteroposterior dimensions of the selected tendons. The QT was evaluated at four levels: at the superior pole of the patella and proximally at three sites with 1 cm distance between them. The PT was evaluated at the inferior pole of the patella, at the tibial tuberosity and at two locations equidistant between the proximal and distal attachment. The HT were assessed at the level of the knee joint line. The statistical analyses were performed using SPSS for Windows (v.26) and more specifically ANOVA (Within/Between), 2-way ANOVA and the t-test for independent samples. For post-hoc comparisons, Bonferroni tests were used. A p-value less than 0.05 considered as statistically significant.
RESULTS: The length of PT was shorter in comparison with the QT (53,1±7,8 mm vs. 71,7±8,6 mm respectively, t=-11,243, p<0,001). Higher values were recorded regarding the perimeter and CSA at the QT in comparison with PT and HT (perimeter QT: 96,52±30,43mm vs. PT: 63,87±8,45mm, HT: 28,01±3,73mm, F=404,629, p<0,001, CSA QT: 231,88±92,82 mm2 vs.PT: 108,35±28,98 mm2 , HT: 26,42±7,15 mm2, F=342,415, p<0,001). The tendons showed significant differences in relation to the sex, tendon type and position as regards the perimeter, CSA and the mediolateral dimensions, but not for the maximum anterioposterior dimension.
CONCLUSIONS: The anatomical variation in dimensions between the various tendons around the knee joint should be taken into account in the preoperative evaluation of the patient who is to undergo ACL reconstruction. Single-site evaluation of a tendon may underestimate or overestimate the size of the potential autograft, depending on the site chosen. Preoperative evaluation of the dimensions of the autografts used in ACL reconstruction may occasionally prove indispensable for the preoperative planning in ACL reconstruction.
Keywords:
Morphometric evaluation, Anterior Cruciate Ligament, MRI 3 Tesla, Autografts, Preoperative evaluation
