• J Hand Surg Am · Mar 2006

    Screw fixation of scaphoid fractures: a biomechanical assessment of screw length and screw augmentation.

    • Seth D Dodds, Manohar M Panjabi, and Joseph F Slade.
    • Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520, USA. sddodds@yahoo.com
    • J Hand Surg Am. 2006 Mar 1; 31 (3): 405-13.

    PurposeTo assess the biomechanical stability relative to screw length and K-wire augmentation in scaphoid fracture fixation using a flexibility testing protocol and cadaver scaphoids whose soft tissue attachments remained undisturbed. Our hypothesis was 2-fold: increasing screw length and augmenting fixation with a K-wire would improve fracture fragment stability, individually and in combination.MethodsFlexion and extension loading applied through wrist tendons was performed on 10 cadaveric wrists after volar wedge scaphoid osteotomy and internal fixation. Each wrist participated in 3 experimental groups: short screw, long screw, and long screw augmented with a K-wire transfixing the distal pole to the capitate. Interfragmentary displacements were measured.ResultsAnalysis of variance showed significantly less fracture fragment motion with longer screws than with short screws in 4 of the 6 displacement axes. The flexion/extension axis rotations for the short, long, and augmented long-screw groups were 8.2 degrees +/- 4.8 degrees, 3.9 degrees +/- 1.6 degrees, and 1.8 degrees +/- 1.3 degrees, respectively. Although K-wire augmentation reduced displacement of the fracture fragments it did not decrease interfragmentary motion significantly when compared with the long-screw group.ConclusionsUnder physiologically applied loading of cadaveric wrists with unstable scaphoid waist fractures the long screw provided significantly greater stability than the short screw. Although K-wire augmentation in the long-screw group did improve stability the improvements were not significant. Based in part on the biomechanical data from this study it is our recommendation that the optimally placed screw for scaphoid fracture fixation stability is a long screw positioned down the central axis of the scaphoid deep into subchondral bone.

      Pubmed     Full text   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…