An Additional Reference Axis Improves Femoral Rotation Alignment in Image-Free Computer Navigation Assisted Total Knee Arthroplasty

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Abstract

Few studies have demonstrated improvement in accuracy of rotational alignment using image-free navigation systems mainly due to the inconsistent registration of anatomical landmarks. We have used an image-free navigation for total knee arthroplasty, which adopts the average algorithm between two reference axes (transepicondylar axis and axis perpendicular to the Whiteside axis) for femoral component rotation control. We hypothesized that addition of another axis (condylar twisting axis measured on a preoperative radiograph) would improve the accuracy. One group using the average algorithm (double-axis group) was compared with the other group using another axis to confirm the accuracy of the average algorithm (triple-axis group). Femoral components were more accurately implanted for rotational alignment in the triple-axis group (ideal: triple-axis group 100%, double-axis group 82%, P < 0.05).

Section snippets

Materials and Methods

Institutional review board approval was received for this study. All patients provided written informed consent.

Of a total of 162 consecutive primary TKA procedures performed in 146 patients between January 2009 and September 2011, 158 knees were replaced using the Stryker 4.0 image-free computer navigation system (Stryker Orthopedics, Mahwah, NJ) equipped with an average algorithm derived from the registered the Whiteside axis and SEA.

Between January 2009 and June 2010, femoral rotational

Results

The average RFC angle was − 0.1° ± 2.4° [mean ± SD, range: 7° of internal rotation to 4° of external rotation] for the double-axis group and 0.3° ± 1.7° (3° of external rotation to 3° of internal rotation) for the triple-axis group. With regard to the average RFC angle, there were no statistically significant differences observed between the two groups.

Thirty-one cases (82%) were implanted ideally (within 3° of neutral) in the double-axis group, whereas all 26 cases (100%) were implanted ideally in

Discussion

Malpositioning of any component can lead to an increased risk of loosening, instability, and pain 3., 4.. Restoration of the tibiofemoral angle to within 3° of neutral during TKA is thought to be associated with a better outcome 4., 5., 6., 21., 22.. Computer-assisted navigation systems are designed to increase the accuracy of implantation, and have become much more accepted and prevalent in recent years. Several studies have demonstrated superior alignment of the components in the coronal

References (28)

  • J. Lutzner et al.

    Functional outcome after computer-assisted versus conventional total knee arthroplasty: a randomized controlled study

    Knee Surg Sports Traumatol Arthrosc

    (2010)
  • D. Nicoll et al.

    Internal rotational error of the tibial component is a major cause of pain after total knee replacement

    J Bone Joint Surg Br

    (2010)
  • R.S. Jeffery et al.

    Coronal alignment after total knee replacement

    J Bone Joint Surg Br

    (1991)
  • G. Matziolis et al.

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

    J Bone Joint Surg Am

    (2007)
  • Cited by (20)

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    The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2013.01.030.

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