Radiographic Study of the Modified Femoral Tunnels of Anterior Cruciate Ligament Reconstruction / 中国运动医学杂志

ABSTRACT

Objective To modify anterior cruciate ligament (ACL)reconstruction to achieve better structure;to measure the tunnel's position and shape using three-dimensional computed tomography (CT)so as to show the change of the femoral bony tunnel.Methods Forty-five patients were diagnosed with an ACL tear and subsequently underwent the modified ACL reconstruction,using a minor-diameter drill to drill the femoral tunnel and then expand it to oval-shaped tunnel with the raspatory between July 2014 and 2015.All procedures were conducted by the same experienced surgeon (Ao Yf.).In all patients,CT was performed at one week after the ACL reconstruction to evaluate the femoral tunnel's positioning,then the CT-images were imported into the image processing software MIMICS to reconstruct the femoral bony tunnel to measure the tunnel's diameters of the section and the shape.The tunnel's position was evaluated using the quadrant method.Results In all the 45 patients,the graft could pass the tunnel.And no posterior tunnel wall blowout,neurological or vascular deficit was documented during the operation.According to the different methods of modification (6 to 7,6 to 8 and 7 to 8),the long diameters of the sections of the femoral bony tunnels were 8.34-± 0.52 mm,10.65 ± 0.72mm,9.27-± 0.11 mm,without significant difference from the theoretical value (8.16 mm,10.66 mm and 9.14 mm).However,the short diameters of the sections were 6.57--0.12 mm,6.74-± 0.13 mm,and 7.52 ± 0.05 mm,showing significant difference from the theoretical value (6mm,6mm and 7 mm).The average centre of the femoral tunnel was located at 26.4 ± 4.8％ of the femoral length and at 30.1 ± 5.6％ of the femoral height.Conclusion In this modified ACL reconstruction,a minor-diameter drill is used to drill the femoral tunnel and then expand it to oval-shaped tunnel with the raspatory,The graft was matched well with the bony tunnel intraoperatively.The three-dimensional CT shows that the femoral tunnels are well located within the anatomical ACL footprint,and its entrance is closer to the natural state.