Purpose: For intra- and postoperative evaluation of precise and anatomic graft tunnel position, radiographs (XR) and computed tomography (CT) scans have been suggested. The purpose of this study was to evaluate the reliability and validity of XR and CT for quality assessment following PCL reconstruction.
Methods: Postoperative radiographs and CT scans were obtained in 45 consecutive patients following a standard single-bundle PCL reconstruction. Femoral and tibial tunnel apertures were correlated to femoral and tibial measurement grid systems. To assess the reliability and validity of XR and CT scans three independent observers evaluated radiographic and CT images for the position of femoral and tibial tunnel apertures.
Results: Almost perfect inter- and intra observer agreement (0.79-0.99) was found for all CT measurements except for the distance of the tunnel position to the previous physis line. Almost perfect and strong inter- and intraobserver agreement (0.70-0.98) was found for all tibial measurements on XR which tended to increase with repeated interpretation and to decrease with low levels of observer qualification. Femoral measurements yielded only poor-to-moderate reliability (0.02-0.5) between raters on XR but strong intraagreement within experienced observers (0.45-0.86). Specificity for XR was calculated with 75.7 % for P2 and P3 and with 71 % for femoral tunnel depth and height.
Conclusion: XR and CT represent complementary imaging modalities and both offer considerable accuracy and precision for the determination of femoral and tibial tunnel apertures following PCL reconstruction and can be recommended for intra- and postoperative quality assessment.