Comparison of trans-cortical and cancellous screws to press fit for acetabular shell fixation in total hip arthroplasty: A cadaveric study. (October 2019)

• Record Type: Journal Article
• Authors: Burkhart, Timothy A.; Khadem, Mehrdad; Wood, Thomas J.; Dunning, Cynthia E.; Degen, Ryan; Lanting, Brent A.
• Is Part Of: Clinical biomechanics. Volume 69(2019)
• Page Start: 34
• Page End: 38
• Publication Date: 2019-10
• Subjects: Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2019.06.017
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: Total hip arthroplasty complications are associated with mechanical loosening of the acetabular component, which may be attributed to the type of fixation used (press fit, trans-cortical screws, cancellous screws). Therefore, the purpose of this study was to compare trans-cortical and cancellous screws to press fit for fixation of the acetabular shell. Methods: Five cadaveric pelvis specimens were hemisected (N = 10) at the sacroiliac joint. Each hemi-pelvis was initially tested with a press fit cup followed by the left and right pairs being randomized to either a cancellous or trans-cortical screw condition. Each fixation was tested by applying a load to a rod inserted into the centre of the acetabular cup at 0.5 mm/s, until failure occurred. The failure force, failure moment, and the rotation angle of the cup at failure were calculated. Findings: The cups fixated with a trans-cortical screw failed at a significantly greater mean [SD] force (1046.20 [386.52] N). The trans-cortical screws also significantly increased the angle of failure 46.29 (16.90) ° compared to the press-fit cups (6.73 [4.59] °). Finally, there was a significant increase in the failure moment, such that, the trans-cortical condition failed at a mean (SD) moment of 53.75 (16.24) Nm compared to 9.59 (1.85) Nm and 32.15 (18.16) Nm for the press fit and cancellous ( p = 0.044) conditions, respectively. Interpretation: The acetabular shells that were fixated with trans-cortical screws provide greater stability compared to the press-fit cups or cancellous screws. Highlights: The type of screw fixation may contribute to hip arthroplasty complications. Trans-cortical screws, cancellous screws, and pres-fit are all viable options. Trans-cortical screws resulted in greater failure force and failure rotation. Trans-cortical-screws resulted in greater failure moment.