• Fanny Schwaabe, Johannes Gleich, Christoph Linhart, Alexander Martin Keppler, Matthias Woiczinski, Christian Kammerlander, Axel Greiner, Wolfgang Böcker, and Adrian Cavalcanti Kußmaul.
• Department of Orthopaedics and Trauma Surgery, Musculoskeletal University Center Munich (MUM), University Hospital, LMU Munich, Marchioninistr. 15, 81377, Munich, Germany.
• Eur J Trauma Emerg Surg. 2022 Aug 1; 48 (4): 3101-3108.

PurposeOsteoporotic bone tissue appears to be an important risk factor for implant loosening, compromising the stability of surgical implants. However, it is unclear whether lumbar measured bone mineral density (BMD) is of any predictive value for stability of surgical implants at the pubic symphysis. This study examines the fixation strength of cortical screws in human cadaver specimens with different BMDs.MethodsThe lumbar BMD of ten human specimens was measured using quantitative computed tomography (qCT). A cut-off BMD was set at 120 mg Ca-Ha/mL, dividing the specimens into two groups. One cortical screw was drilled into each superior pubic ramus. The screw was withdrawn in an axial direction with a steady speed and considered failed when a force decrease was detected. Required force (N) and pull-out distance (mm) were constantly tracked.ResultsThe median peak force of group 1 was 231.88 N and 228.08 N in group 2. While BMD values differed significantly (p < 0.01), a comparison of peak forces between both groups showed no significant difference (p = 0.481).ConclusionHigher lumbar BMD did not result in significantly higher pull-out forces at the symphysis. The high proportion of cortical bone near the symphyseal joint allows an increased contact of pubic screws and could explain sufficient fixation. This condition is not reflected by a compromised lumbar BMD in a qCT scan. Therefore, site-specific BMD measurement could improve individual fracture management.© 2021. The Author(s).

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