• Arch Orthop Trauma Surg · Jan 2017

    Does a positioning rod or a patient-specific guide result in more natural femoral flexion in the concept of kinematically aligned total knee arthroplasty?

    • Max Ettinger, Tilman Calliess, and Stephen M Howell.
    • Department of Orthopedic Surgery, Hannover Medical School, Hannover, Germany. Max@ettinger.info.
    • Arch Orthop Trauma Surg. 2017 Jan 1; 137 (1): 105-110.

    PurposeFlexion of the femoral component in 5° increments downsizes the femoral component, decreases the proximal reach and surface area of the trochlea, delays the engagement of the patella during flexion, and is associated with a higher risk of patellar-femoral instability after kinematically aligned TKA. The present study evaluated flexion of the femoral component after use of two kinematic alignment instrumentation systems. We determined whether a distal cutting block attached to a positioning rod inserted perpendicular to the distal femoral joint line in the axial plane and 8-10 cm into the distal femur anterior and posterior to the distal cortex of the femur in the sagittal plane or a femoral patient-specific cutting guide sets the femoral component in more natural flexion.MethodsFlexion of the femoral component was measured with respect to the sagittal femoral anatomic axis of the distal diaphysis and the sagittal femoral axis on rotationally controlled long-leg lateral computer scanograms. Measurements were performed on 53 consecutive patients treated with a kinematically aligned TKA performed with a distal cutting block attached to a positioning rod, and 53 consecutive patients treated with a kinematically aligned TKA performed with a femoral patient-specific cutting guide.ResultsThe average flexion and variability (±standard deviation) of the femoral component of patients treated with a positioning rod was 1° ± 2° and 7° ± 4° with respect to the anatomic and mechanical axes, respectively, which was 5° less than the average flexion of the femoral component of patients treated with a femoral patient-specific cutting guide of 6° ± 4° and 12° ± 5° (p = 0.0001, p = 0.0001, respectively).ConclusionsBecause a distal cutting block attached to a positioning rod sets the femoral component in 5° less flexion and with less variability than a femoral patient-specific cutting guide, we prefer this instrumentation system when performing kinematically aligned TKA to reduce the risk of patellar-femoral instability. Each surgeon should determine the repeatability of setting the flexion of the femoral component with this instrumentation system.

      Pubmed     Copy Citation     Plaintext  

      Add institutional full text...

    Notes

     
    Knowledge, pearl, summary or comment to share?
    300 characters remaining
    help        
    You can also include formatting, links, images and footnotes in your notes
    • Simple formatting can be added to notes, such as *italics*, _underline_ or **bold**.
    • Superscript can be denoted by <sup>text</sup> and subscript <sub>text</sub>.
    • Numbered or bulleted lists can be created using either numbered lines 1. 2. 3., hyphens - or asterisks *.
    • Links can be included with: [my link to pubmed](http://pubmed.com)
    • Images can be included with: ![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
    • For footnotes use [^1](This is a footnote.) inline.
    • Or use an inline reference [^1] to refer to a longer footnote elseweher in the document [^1]: This is a long footnote..

    hide…

Want more great medical articles?

Keep up to date with a free trial of metajournal, personalized for your practice.
1,694,794 articles already indexed!

We guarantee your privacy. Your email address will not be shared.