The posterior drawer test is an accurate clinical test to diagnose posterior cruciate ligament (PCL), indicating laxity of the PCL that allows posterior tibial translation. This study aimed to determine whether posterior tibial translation relative to the femur on routine MRI could serve as an additional sign of PCL tear. Routine knee MRI in eleven patients (7 males, 4 females) with arthroscopically confirmed isolated PCL tears were reviewed independently by two musculoskeletal radiologists. Measurements of tibial translation were made in the medial and lateral compartments of patients and controls (10 males, 12 females) without clinical or MRI evidence of ligament injury. Significant medial compartment posterior tibial translation was present in patients with PCL tear compared to controls (+2.93？mm versus +0.03？mm, ) with excellent interobserver agreement (intraclass correlation coefficient (ICC) = 0.94). No significant difference in lateral compartment tibial translation was observed (+0.17？mm versus ？0.57？mm, ) despite excellent interobserver agreement (ICC = 0.96). Posterior tibial translation in the midmedial compartment may be a secondary sign of isolated PCL tear on routine knee MRI with passive extension without manipulation or weight bearing. Additional work in a larger cohort may better address the accuracy of this finding. 1. Introduction Posterior cruciate ligament (PCL) tears can have deleterious long-term consequences and therefore surgical repair has become a more widely utilized treatment option. In the setting of multiligament injuries, arthroscopy for other injuries may reveal occult PCL tears. In the setting of isolated PCL tear where arthroscopy is not performed, PCL tears that are missed clinically might only be detected on MRI. However, discontinuity of the PCL is not always seen on MRI. Therefore, various indirect signs have been invoked to diagnose PCL tears. Several indirect signs of PCL tears have been suggested, including posterior cruciate ligament thickness, ligamentous laxity, and increased intrasubstance signal [1]. The posterior drawer test is the most accurate clinical test to diagnose PCL tears; however, posterior subluxation often cannot be elicited with this maneuver in the acute setting due to soft tissue swelling and pain [2]. The purpose of this study is to determine if there is significant passive posterior translocation of the tibia relative to the femur in patients with isolated PCL tears on routine MR imaging without weight-bearing or manipulation. 2. Materials and Methods 2.1. Study Participants Institutional
References
[1]
W. Rodriguez Jr., E. N. Vinson, C. A. Helms, and A. P. Toth, “MRI appearance of posterior cruciate ligament tears,” American Journal of Roentgenology, vol. 191, no. 4, pp. W155–W159, 2008.
[2]
D. C. Covey, “Injuries of the posterolateral corner of the knee,” Journal of Bone & Joint Surgery. American Volume A, vol. 83, pp. 106–108, 2001.
[3]
T. N. Vahey, J. E. Hunt, and K. D. Shelbourne, “Anterior translocation of the tibia at MR imaging: a secondary sign of anterior cruciate ligament tear,” Radiology, vol. 187, no. 3, pp. 817–819, 1993.
[4]
A. J. Cosgarea and P. R. Jay, “Posterior cruciate ligament injuries: evaluation and management,” The Journal of the American Academy of Orthopaedic Surgeons, vol. 9, no. 5, pp. 297–307, 2001.
[5]
J. S. Torg, T. M. Barton, H. Pavlov, and R. Stine, “Natural history of the posterior cruciate ligament-deficient knee,” Clinical Orthopaedics and Related Research, no. 246, pp. 208–216, 1989.
[6]
M. S. Schulz, K. Russe, A. Weiler, H. J. Eichhorn, and H. J. Strobel, “Epidemiology of posterior cruciate ligament injuries,” Archives of Orthopaedic and Trauma Surgery, vol. 123, no. 4, pp. 186–191, 2003.
[7]
M. J. Strobel, A. Weiler, M. S. Schulz, K. Russe, and H. J. Eichhorn, “Arthroscopic evaluation of articular cartilage lesions in posterior cruciate ligament—deficient knees,” Arthroscopy—Journal of Arthroscopic and Related Surgery, vol. 19, no. 3, pp. 262–268, 2003.
[8]
O. C. Brantigan and A. F. Voshell, “The mechanics of the ligaments and menisci of the knee joint,” The Journal of Bone & Joint Surgery, vol. 23, no. 1, pp. 44–66, 1941.
[9]
M. Logan, A. Williams, J. Lavelle, W. Gedroyc, and M. Freeman, “The effect of posterior cruciate ligament deficiency on knee kinematics,” The American Journal of Sports Medicine, vol. 32, no. 8, pp. 1915–1922, 2004.
[10]
E. S. Grood, S. F. Stowers, and F. R. Noyes, “Limits of movement in the human knee. Effect of sectioning the posterior cruciate ligament and posterolateral structures,” Journal of Bone and Joint Surgery, vol. 70, no. 1, pp. 88–97, 1988.
[11]
F. Margheritini and P. P. Mariani, “Diagnostic evaluation of posterior cruciate ligament injuries,” Knee Surgery, Sports Traumatology, Arthroscopy, vol. 11, no. 5, pp. 282–288, 2003.
[12]
F. R. Noyes, S. F. Stowers, E. S. Grood, J. Cummings, and L. A. VanGinkel, “Posterior subluxations of the medial and lateral tibiofemoral compartments. An in vitro ligament sectioning study in cadaveric knees,” The American Journal of Sports Medicine, vol. 21, no. 3, pp. 407–414, 1993.
[13]
J. C. Hughston, “The absent posterior drawer test in some acute posterior cruciate ligament tears of the knee,” The American Journal of Sports Medicine, vol. 16, no. 1, pp. 39–43, 1988.
[14]
T. Akisue, M. Kurosaka, S. Yoshiya, R. Kuroda, and K. Mizuno, “Evaluation of healing of the injured posterior cruciate ligament: analysis of instability and magnetic resonance imaging,” Arthroscopy, vol. 17, no. 3, pp. 264–269, 2001.
[15]
H. Iwaki, V. Pinskerova, and M. A. R. Freeman, “Tibiofemoral movement 1: the shape and relative movements of the femur and tibia in the unloaded cadaver knee,” Journal of Bone and Joint Surgery, vol. 82, no. 8, pp. 1189–1195, 2000.
