This article was originally published here

Eur J Trauma Emerg Surg. December 8, 2021. doi: 10.1007/s00068-021-01850-6. Online before printing.

Purpose: Osteoporotic bone tissue seems to be an important risk factor for implant loosening, which will affect the stability of surgical implants. However, it is not clear whether the measured bone mineral density (BMD) of the lumbar spine has any predictive value for the stability of the pubic symphysis implant. This study examined the fixation strength of cortical screws in human cadaver specimens with different BMD.

Methods: Quantitative computed tomography (qCT) was used to measure the lumbar spine BMD of ten human specimens. The cut-off BMD was set to 120 mg Ca-Ha/mL, and the samples were divided into two groups. A cortical screw was drilled for each suprapubic branch. The screw is withdrawn along the axial direction at a steady speed, and when the force is detected to decrease, the screw is considered to have failed. The force (N) and pull-out distance (mm) required to keep track of.

Results: The median peak force of the first group was 231.88 N, and the second group was 228.08 N. Although the BMD values ​​were significantly different (p <0.01), the comparison of the peak force between the two groups showed no significant difference (p = 0.481).

Conclusion: A higher BMD of the lumbar spine does not cause a significant increase in the pull-out force at the joint. The high proportion of cortical bone close to the joint joint allows for increased pubic screw contact and can account for adequate fixation. This situation will not be reflected by the damaged lumbar spine BMD in the qCT scan. Therefore, BMD measurement at a specific site can improve individual fracture management.

PMID: 34881391 | DOI: 10.1007/s00068-021-01850-6