Clinical Orthopaedics and Related Research®

, Volume 470, Issue 1, pp 99–107

Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA

  • Vincent Y. Ng
  • Jeffrey H. DeClaire
  • Keith R. Berend
  • Bethany C. Gulick
  • Adolph V. LombardiJr
Symposium: Papers Presented at the Annual Meetings of The Knee Society

DOI: 10.1007/s11999-011-1996-6

Cite this article as:
Ng, V.Y., DeClaire, J.H., Berend, K.R. et al. Clin Orthop Relat Res (2012) 470: 99. doi:10.1007/s11999-011-1996-6

Abstract

Background

Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.

Questions/purposes

We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components.

Methods

We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon’s cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes.

Results

The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3° hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9° versus 90.4°) and femoral (90.7° versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the rate of ± 2° outliers was similar for both the tibia (10% versus 7%) and femur (22% versus 18%).

Conclusions

Patient-specific positioning guides can assist in achieving a neutral mechanical axis with reduction in outliers.

Level of Evidence

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Copyright information

© The Association of Bone and Joint Surgeons® 2011

Authors and Affiliations

  • Vincent Y. Ng
    • 1
  • Jeffrey H. DeClaire
    • 2
  • Keith R. Berend
    • 1
    • 3
    • 4
  • Bethany C. Gulick
    • 3
  • Adolph V. LombardiJr
    • 3
    • 4
    • 5
  1. 1.Department of OrthopaedicsThe Ohio State University Medical CenterColumbusUSA
  2. 2.The DeClaire Knee and Orthopaedic InstituteRochester HillsUSA
  3. 3.Joint Implant Surgeons, IncNew AlbanyUSA
  4. 4.Mount Carmel Health SystemNew AlbanyUSA
  5. 5.Department of Orthopaedics and Department of Biomedical EngineeringThe Ohio State University Medical CenterColumbusUSA

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