Kuwashima Umito    Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine    Position   Assistant Professor
Article types	Original article
Language	English
Peer review	Peer reviewed
Title	Three-dimensional analysis of accuracy of patient-matched instrumentation in total knee arthroplasty: Evaluation of intraoperative techniques and postoperative alignment.
Journal	Formal name：Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association Abbreviation：J Orthop Sci ISSN code：14362023/09492658
Domestic / Foregin	Foregin
Volume, Issue, Page	22(6),pp.1077-1083
Author and coauthor	Kuwashima Umito, Mizu-Uchi Hideki, Okazaki Ken, Hamai Satoshi, Akasaki Yukio, Murakami Koji, Nakashima Yasuharu
Authorship	Lead author
Publication date	2017/11
Summary	BACKGROUND:It is questionable that the accuracies of patient-matched instrumentation (PMI) have been controversial, even though many surgeons follow manufacturers' recommendations. The purpose of this study was to evaluate the accuracy of intraoperative procedures and the postoperative alignment of the femoral side using PMI with 3-dimensional (3D) analysis.METHODS:Eighteen knees that underwent total knee arthroplasty using MRI-based PMI were assessed. Intraoperative alignment and bone resection errors of the femoral side were evaluated with a CT-based navigation system. A conventional adjustable guide was used to compare cartilage data with that derived by PMI intraoperatively. Postoperative alignment was assessed using a 3D coordinate system with a computer-assisted design software. We also measured the postoperative alignments using conventional alignment guides with the 3D evaluation.RESULTS:Intraoperative coronal alignment with PMI was 90.9° ± 1.6°. Seventeen knees (94.4%) were within 3° of the optimal alignment. Intraoperative rotational alignment of the femoral guide position of PMI was 0.2° ± 1.6°compared with the adjustable guide, with 17 knees (94.4%) differing by 3° or less between the two methods. Maximum differences in coronal and rotation alignment before and after bone cutting were 2.0° and 2.8°, respectively. Postoperative coronal and rotational alignments were 89.4° ± 1.8° and -1.1° ± 1.3°, respectively. In both alignments, 94.4% of cases were within 3° of the optimal value. The PMI group had less outliers than conventional group in rotational alignment (p = 0.018).CONCLUSIONS:Our 3D analysis provided evidence that PMI system resulted in reasonably satisfactory alignments both intraoperatively and postoperatively. Surgeons should be aware that certain surgical techniques including bone cutting, and the associated errors may affect postoperative alignment despite accurate PMI positioning.
DOI	10.1016/j.jos.2017.08.010
PMID	28888738