A prospective, randomized study of computer-assisted and conventional total knee arthroplasty. Three-dimensional evaluation of implant alignment and rotation.

BACKGROUND Despite the use of modern instruments in total knee arthroplasty, component malalignment remains a problem. Whether a computer-assisted implantation technique can improve the accuracy of the spatial positioning of an implant is a matter of debate. The objective of this study was to determine whether computer-assisted total knee arthroplasty is superior to the conventional surgical method with regard to the precision of implant positioning. METHODS The spatial positioning of the implant in sixty total knee arthroplasties (thirty-two imageless computer-assisted and twenty-eight conventional implantations) was determined three-dimensionally with use of computed tomographic measurement, which allowed derotation and full extension of the knee in order to avoid projection-related imaging errors. RESULTS The overall mechanical axis showed a range of between 4.8 degrees of valgus and 6.6 degrees of varus alignment in the frontal plane for conventionally implanted arthroplasty components compared with a significantly smaller range of between 2.9 degrees of valgus and 3.1 degrees of varus alignment for computer-assisted implantations (p = 0.004). In relation to the tibial implant, the mean deviation (and standard deviation) from the mechanical axis was 2.0 degrees +/- 1.7 degrees for the conventional surgical method and 1.4 degrees +/- 0.9 degrees for the navigated implantation. The rotational deviation from the referenced axis of the femoral component was between 3.3 degrees of internal rotation and 5.0 degrees of external rotation for the conventional implantation method, with a mean deviation of 0.1 degrees +/- 2.2 degrees. Femoral components implanted with computer assistance showed a deviation of between 4.7 degrees of internal rotation and 2.2 degrees of external rotation, with a mean deviation of 0.3 degrees +/- 1.4 degrees. CONCLUSIONS In this study, with our technique of filtering out projection-related imaging errors, computer-assisted implantation of total knee replacements improved the frontal and sagittal alignment of the femoral component but not of the tibial component. We found that the rotational alignment of the component was not improved through navigation by solely referencing to the epicondylar axis for the femur and the tuberosity for the tibia.

[1]  D. Zurakowski,et al.  Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. , 2004, The Journal of bone and joint surgery. British volume.

[2]  D. Dennis,et al.  Correlation Between Condylar Lift-Off and Femoral Component Alignment , 2002, Clinical orthopaedics and related research.

[3]  Anthony J. Petrella,et al.  Optimizing Femoral Component Rotation in Total Knee Arthroplasty , 2001, Clinical orthopaedics and related research.

[4]  Peter Loan,et al.  Computer-Assisted Navigation in Total Knee Replacement: Results of an Initial Experience in Thirty-five Patients , 2002, The Journal of bone and joint surgery. American volume.

[5]  L. Dorr,et al.  Rationale of the Knee Society clinical rating system. , 1989, Clinical orthopaedics and related research.

[6]  J. J. Jacobs,et al.  Malrotation Causing Patellofemoral Complications After Total Knee Arthroplasty , 1998, Clinical orthopaedics and related research.

[7]  U Holz,et al.  [CT analysis of leg alignment after conventional vs. navigated knee prosthesis implantation. Initial results of a controlled, prospective and randomized study]. , 2003, Der Unfallchirurg.

[8]  Martin Stockheim,et al.  Computer-Assisted Navigation Increases Precision of Component Placement in Total Knee Arthroplasty , 2005, Clinical orthopaedics and related research.

[9]  N. Suzuki,et al.  Effects of rotation on measurement of lower limb alignment for knee osteotomy , 2004, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[10]  M. Ritter,et al.  Postoperative alignment of total knee replacement. Its effect on survival. , 1994, Clinical orthopaedics and related research.

[11]  P. Lotke,et al.  Influence of positioning of prosthesis in total knee replacement. , 1977, The Journal of bone and joint surgery. American volume.

[12]  L. Whiteside,et al.  The Anteroposterior Axis for Femoral Rotational Alignment in Valgus Total Knee Arthroplasty , 1995, Clinical orthopaedics and related research.

[13]  Cyril Boeri,et al.  Low reproducibility of the intra–operative measurement of the transepicondylar axis during total knee replacement , 2004, Acta orthopaedica Scandinavica.

[14]  Tomoyuki Saito,et al.  Underestimation of varus angulation in knees with flexion deformity. , 2002, The Knee.

[15]  D. Banzer,et al.  Positioning of total knee arthroplasty with and without navigation support. A prospective, randomised study. , 2003, The Journal of bone and joint surgery. British volume.

[16]  C. Olcott,et al.  The Ranawat Award. Femoral component rotation during total knee arthroplasty. , 1999, Clinical orthopaedics and related research.

[17]  K A Krackow,et al.  A mathematical analysis of the effect of flexion and rotation on apparent varus/valgus alignment at the knee. , 1990, Orthopedics.

[18]  Pak Lin Chin,et al.  Randomized control trial comparing radiographic total knee arthroplasty implant placement using computer navigation versus conventional technique. , 2005, The Journal of arthroplasty.

[19]  W. Mihalko,et al.  The variability of intramedullary alignment of the femoral component during total knee arthroplasty. , 2005, The Journal of arthroplasty.

[20]  J. Moreland Mechanisms of failure in total knee arthroplasty. , 1988, Clinical orthopaedics and related research.

[21]  Michael Nogler,et al.  Navigation Improves Accuracy of Rotational Alignment in Total Knee Arthroplasty , 2004, Clinical orthopaedics and related research.

[22]  C. Olcott,et al.  Femoral component rotation during total knee arthroplasty , 1999 .

[23]  M. Akagi,et al.  Effect of rotational alignment on patellar tracking in total knee arthroplasty. , 1999, Clinical orthopaedics and related research.

[24]  D. Shakespeare,et al.  Can the epicondylar axis be defined accurately in total knee arthroplasty? , 2005, The Knee.

[25]  W. Breidahl,et al.  Computer-assisted knee arthroplasty versus a conventional jig-based technique. A randomised, prospective trial. , 2004, The Journal of bone and joint surgery. British volume.

[26]  D. Dennis,et al.  The Impact of Femoral Component Rotational Alignment on Condylar Lift-Off , 2003, Clinical orthopaedics and related research.

[27]  L. Whiteside,et al.  The effects of axial rotational alignment of the femoral component on knee stability and patellar tracking in total knee arthroplasty demonstrated on autopsy specimens. , 1993, Clinical orthopaedics and related research.

[28]  Mark H. Gonzalez,et al.  The Failed Total Knee Arthroplasty: Evaluation and Etiology , 2004, The Journal of the American Academy of Orthopaedic Surgeons.

[29]  M. Tingart,et al.  Navigation in total-knee arthroplastyCT-based implantation compared with the conventional technique , 2004, Acta orthopaedica Scandinavica.

[30]  Frederick W Werner,et al.  The effect of valgus/varus malalignment on load distribution in total knee replacements. , 2005, Journal of biomechanics.

[31]  B. Philipps,et al.  Interindividual reproducibility in perioperative rotational alignment of femoral components in knee prosthetic surgery using the transepicondylar axis , 2002, Knee Surgery, Sports Traumatology, Arthroscopy.

[32]  V. Spitzer,et al.  Three-Dimensional Morphology and Kinematics of the Distal Part of the Femur Viewed in Virtual Reality: Part II , 2003, The Journal of bone and joint surgery. American volume.

[33]  R. Barrack,et al.  Component Rotation and Anterior Knee Pain After Total Knee Arthroplasty , 2001, Clinical orthopaedics and related research.

[34]  C. Boéri,et al.  Computer-assisted implantation of total knee prostheses: a case-control comparative study with classical instrumentation. , 2001, Computer aided surgery : official journal of the International Society for Computer Aided Surgery.

[35]  R. Morris,et al.  Coronal alignment after total knee replacement. , 1991, The Journal of bone and joint surgery. British volume.

[36]  M. Ritter,et al.  Tibial Component Failure Mechanisms in Total Knee Arthroplasty , 2004, Clinical orthopaedics and related research.