Document Detail

Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA.
MedLine Citation:
PMID:  21809150     Owner:  NLM     Status:  MEDLINE    
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.
Vincent Y Ng; Jeffrey H DeClaire; Keith R Berend; Bethany C Gulick; Adolph V Lombardi
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Clinical orthopaedics and related research     Volume:  470     ISSN:  1528-1132     ISO Abbreviation:  Clin. Orthop. Relat. Res.     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2011-12-15     Completed Date:  2012-08-16     Revised Date:  2013-06-28    
Medline Journal Info:
Nlm Unique ID:  0075674     Medline TA:  Clin Orthop Relat Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  99-107     Citation Subset:  AIM; IM    
Department of Orthopaedics, The Ohio State University Medical Center, Columbus, OH, USA.
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MeSH Terms
Aged, 80 and over
Arthroplasty, Replacement, Knee / adverse effects,  instrumentation*,  methods*
Bone Malalignment / prevention & control*
Femur / surgery
Follow-Up Studies
Intraoperative Care / instrumentation*,  methods
Knee Prosthesis
Middle Aged
Osteoarthritis, Knee / radiography,  surgery*
Patient Positioning / methods*
Range of Motion, Articular / physiology
Recovery of Function
Risk Assessment
Tibia / surgery
Treatment Outcome

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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