The Effect of Notchplasty on Tunnel Widening in Anterior Cruciate Ligament Reconstruction Young-Jin Seo, M.D., Ph.D., Yon-Sik Yoo, M.D., Ph.D., Yoon Sang Kim, Ph.D., Seong-Wook Jang, M.S., Si Young Song, M.D., Yoon Suk Hyun, M.D., Patrick Smolinski, Ph.D., and Freddie H. Fu, M.D., D.Sc. Purpose: To investigate changes in femoral tunnel diameter, dimension, and volume after anterior cruciate ligament reconstruction with notchplasty. Methods: Porcine knee specimens were divided into 2 groups of 10 specimens each. Group A did not receive notchplasty. A 2-mm notchplasty was conducted in group B. Seven-millimeter-diameter femoral tunnels were drilled and a doubled flexor digitorum profundus tendon was inserted and fixed with an EndoButton (Smith & Nephew, Andover, MA) in each knee specimen. Samples were mounted on a materials testing machine. Each group was preloaded at 10 N and subjected to 20 loading cycles (between 0 and 40 N), followed by 1,000 loading cycles in the elastic region (between 10 and 150 N). High-resolution computed tomography with 1.0-mm slices was conducted with all samples before and after testing. A 3-dimensional model was constructed to evaluate the degree of the tunnel change. Results: In group B the mean longest diameter and dimension of the femoral tunnel significantly increased after the test (P ¼ .005 and P ¼ .001, respectively). The volumetric loss of bony structure after the test in group B was significantly greater than that in group A (P ¼ .039). Meanwhile, no significant difference was found before and after the test in terms of tunnel diameter, dimension, and volumetric loss around the tunnel in group A. Conclusions: The intra-articular orifice of the femoral tunnel was enlarged after the uniaxial cyclic loading test after notchplasty. An enlarged tunnel orifice may lead to a discrepancy between the tunnel and the graft at the tunnel aperture. Clinical Relevance: The data may have an implication that suspensory fixation with a notchplasty has a negative effect on the full graft accommodation at the tunnel aperture. Aperture widening may affect graft positioning, leading to subtle changes in graft biomechanics and laxity. N otchplasty is performed during anterior cruciate ligament (ACL) reconstruction to improve visu- alization of the posterior wall, allow for easier passage of the graft, and prevent impingement of the graft. Notchplasty is especially useful in cases of a congenitally narrow notch and stenosing osteophytes in chronically unstable knees. 1 However, the amount of bone to remove remains controversial, and whether to extend the notchplasty back to the posterior wall is debatable. Studies have suggested that 2 mm to 25% of the lateral femoral condyle needs to be removed, 2-4 with an increased notch width to 21 mm to create clearance for the graft when the knee is in extension. 5 However, obvious concerns have arisen recently because notch- plasty may displace the femoral insertion of the ACL laterally, leading to abnormal knee kinematics. 6,7 Although the close anatomic relation between the ACL and the lateral wall of the intercondylar notch has long been recognized, no study has shown the impor- tance of the dense inner cortex covering the normal ACL footprint as a key structure to prevent initial tun- nel enlargement. A cadaveric anatomic study showed various cortical thicknesses in the lateral wall and roof of the intercondylar notch ranging from 0.90 to 1.60 mm. 8 This finding prompted our study. Furthermore, the anterior rim of the intercondylar notch wall has been reported to have an effect on the development of a fibrocartilaginous zone in the anterior portion of the ACL approximately 5 to 10 mm proximal to the tibial insertion, where the ligament faces this region in full From the Department of Orthopedic Surgery, Hallym University Medical Center (Y-J.S., Y-S.Y., S.Y.S., Y.S.H.), Dongtan; HiLab, Korea University of Technology and Education (Y.S.K., S-W.J.), Cheonan, South Korea; and Department of Orthopedic Surgery, University of Pittsburgh Medical Center (P.S., F.H.F.), Pittsburgh, Pennsylvania, U.S.A. This work was supported by a grant from Hallym University Medical Center Research Fund (01-2010-14). The authors report that they have no conflicts of interest in the authorship and publication of this article. Received August 22, 2013; accepted February 14, 2014. Address correspondence to Yon-Sik Yoo, M.D., Ph.D., Department of Or- thopedic Surgery, Hallym University Medical Center, Dongtan, Sugwoodong 40, Hwasung City, Gyunggido, South Korea. E-mail: ybw1999@gmail.com Ó 2014 by the Arthroscopy Association of North America 0749-8063/13613/$36.00 http://dx.doi.org/10.1016/j.arthro.2014.02.024 Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol -, No - (Month), 2014: pp 1-8 1