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Deutscher Kongress für Orthopädie und Unfallchirurgie
73. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie
95. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie
50. Tagung des Berufsverbandes der Fachärzte für Orthopädie und Unfallchirurgie

21. - 24.10.2009, Berlin

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Effect of varying posterior tibial slopes on intra-operative passive flexion in total knee arthroplasty

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  • J. Mabrey - Baylor University Medical Center, Dallas, Tx, United States
  • D. Covall - Resurgens Orthopaedics, Cumming, United States
  • B. N. Stulberg - The Cleveland Center for Joint Reconstruction, Cleveland, OH, United States
  • A. Burstein - Exactech Inc., Gainsville, United States
  • L. D. Angibaud - Exactech Inc., Gainsville, United States
  • K. Smith - Exactech Inc., Gainsville, United States

Deutscher Kongress für Orthopädie und Unfallchirurgie. 73. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 95. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie, 50. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 21.-24.10.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocEF17-1336

doi: 10.3205/09dkou071, urn:nbn:de:0183-09dkou0717

Published: October 15, 2009

© 2009 Mabrey et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Text

Problem: The goal of cruciate retaining total knee arthroplasty (TKA) is to preserve the integrity of the posterior cruciate ligament (PCL) in an effort to optimize performance and maintain joint stability. However the PCL can be compromised during tibial resection that either removes too much bone or is too sloped. In the event a tibia requires further resection, the PCL is at risk of dissection. A method where surgeons can verify maximum passive flexion has been developed, and this study was conducted to determine the effects of tibial inserts with varying posterior slopes on intra-operative passive flexion with an intact PCL.

Methods: An Institutional Review Board-approved prospective, consecutive series was initiated April 2008 at three different US centers, by three senior surgeons. The mean proximal tibial cut was performed at a 3 degree posterior tibial slope for all subjects. Passive flexion measurements were obtained intra-operatively with a goniometer using the 0, 3 and then 6 degree tibial insert trials, with thicknesses ranging from 9mm to 13 mm. Final implanted tibial inserts were also recorded for each subject.

Results and conclusions: Subjects (n=30) had average age of 63.4 years (38-84 years). Average pre-operative Knee Society Score (KSS) knee and function scores were 41.3 and 58.3, respectively. Average intra-operative flexion for the 0, 3 and 6 degree tibial insert trials were 113.9, 119.1 and 123.4 degrees, respectively. The average flexion differences between standard and sloped trials were 5.2 and 9.5 degrees, statistically significant findings in each group (p<0.05). The 3 degree tibial insert was implanted in 21 subjects and the 6 degree tibial insert was implanted in 9 subjects.

Higher intra-operative flexion was positively correlated with increasing tibial insert slope. Subsequent to the initial proximal tibial resection, the surgeon can additionally use the 0, 3 and 6 degree tibial insert trials to determine maximum flexion. In this series, final implant selection was based on optimum motion and stability. Study results demonstrate that varying sloped tibial inserts may facilitate preservation of the PCL (and contribute to stable knee kinematics).