| Background:Dual-source CT (DSCT) owns two sets of x-ray tube and two sets of detection systemto collect the body image at the same time. Its working principle is to use two sets of x-raygenerator and detector system on the same plane in a certain way to obtain scanningimaging of human body. Two sets of x-ray tube emit x-rays in the same or differentvoltage and then integrate data together or respectively. The data gotten from the sameorgans and tissues by two sets is different in resolution, therefore the tissue structure beable to demonstrate better and faster with DSCT than ordinary CT. DSCT has beenutilized in the heart and coronary artery imaging, neck and chest, cartilage, bone, tendonand ligament, emergency and many other aspects.Objective:⑴To explore a positioning system for the femoral foot-print of anterior cruciateligament and provide basic data which is feasible for arthroscopic positioning the femoraltunnel in ACL reconstruction. ⑵To verify the feasibility and repeatability of the validation method in clinicalapplication in an attempt to maximize the foot-print recovery and achieve individualizedACL reconstructionMethod:PartⅠ⑴External wall of the lateral femoral condyle was three-dimensionally reconstructedwith dual-source CT and workstation in69knees, including50male and19female, agedfrom14~57years old with the average age of29. The femoral foot-print of ACL wasoutlined on the images and one or two central points was marked based on the single ordouble-bundle pattern according to the foot-print shape. Blumensaat line was also drawnand the turning point from posterior cartilage of lateral femoral condyle to posteriorfemoral metaphysis was defined as point O. The distance from O to each foot-print centerand angle between Blumensaat line and line of point O to foot-print center were measured.The samples were divided into two groups on the basis of foot-print shape, group oneowns circular shape foot-print which was supposed to be reconstructed with single bundleand group two has an oval print in shape which was likely to be reconstructed withdouble-bundle. In the light of physiological principle, a known distance and angle candefine a point on a plane, therefore, we can define the central point of foot-print, single ordouble, referring to the point O and Blumensaat line.PartⅡ⑵In selected20ACL injury patients, including10male and10female, aged19~48years old in an average of24years old. The injured knee was scanned with DSCTpreoperatively according to the method in part1. The shape and center(s) of foot-print ofACL femoral insertion were marked and the angle(s) and distance(s) were also measuredas well. Femoral tunnel(s) was established intraoperatively based on the measurements ofangle and distance. DSCT scan was undertaken again on the same knee postoperatively,the tunnel position was compared with the location we marked before operation inconsistency to verify the feasibility and repeatability of the positioning method. Results:⑴In the group one consisted of37knees, the distance from point O to foot-print centerwas1.24cm in average(from0.95cm to1.68cm), the angel between Blumensaat line andline from point O to foot-print center was43.4°in average(range from32.6°to58.2°). Ingroup two which consisted of32knees, the distance from point O to AM foot-print centerwas0.90cm in average(from0.64cm to1.20cm), the angel between Blumensaat line andline from point O to AM foot-print center was44.5°in average(range from31.8°to72.3°),the angel between Blumensaat line and line from point O to PL foot-print center was1.48cm in average(range from1.11cm to1.78cm). the angel between Blumensaat line andline from point O to PL foot-print center was47.9°in average(range from39.1°to59.3°)⑵Postoperative patients postoperative femoral tunnel position and determine itslocation and position is consistent, preoperative testing method is feasible and goodrepeatability.Conclusion:A femoral foot-print positioning method we developed based on dual-source CT scanmodel is able to define the femoral footprint position. Based on the footprint shape,patients with ACL injured can be individualized into single or double bundlereconstruction during preoperative planning. Based on the angle and distance whichmeasured before operation, anatomic femoral insertion of ACL can be defined and createdunder arthroscopy at femoral site and a further step to anatomic reconstruction of ACL hasbeen made. |
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