SupraFusion - Implant Stability in Osteopenic Bone
The bone augmenting bond created by SupraFusion enhances fixation strength compared to corkscrew anchoring, particularly in osteopenic bone.
Pull-out strength in varying bone densities
Achieving reliable implant stability in osteopenic bone is a significant challenge in orthopedic and sports medicine. Reduced BMD compromises the bone’s mechanical integrity, increasing the risk of implant loosening and fixation failure, which can negatively affect post-operative outcomes. Devices that provide secure fixation in low-density bone are necessary to mitigate these risks.
In this evaluation, we compared the pull-out strength of an ultrasonically inserted PL-(DL)-LA implant with a metallic corkscrew suture anchor across a broad range of bone densities [1].
As shown in Figure 1, the SupraFusion bond shows a distinctly different failure behavior than the screw:
The bone augmentation through SupraFusion strengthens the bone structure adjacent to implant and, consequently, the failure happens distant to the implant site and not at the implant-bone interface.
The screw geometry acts as a stress riser and induces bone fracture at the tip of the screw thread.
This difference in failure mechanisms creates a fundamental change in mechanical performance. The pull-out strength for the SupraFusion implant is controlled by bone density and is significantly higher than that of the corkscrew anchor overall. This results in better mechanical engagement in low-density bone.
Reference
[1] D. C. Meyer, E. Felix, K. Ruffieux, and C. Gerber, ‘Influence of test temperature and test speed on the mechanical strength of absorbable suture anchors’, Arthroscopy, vol. 20, no. 2, pp. 185–190, Feb. 2004, doi: 10.1016/j.arthro.2003.11.014.
Figure 1
Relationship between bone density and the pull-out strength for two fixation devices: a SupraFusion PL-(DL)-LA implant (diameter 3.5mm, blue line) and a Titanium Corkscrew anchor (diameter 5.0mm, red line). The picture illustrates the fundamentally different failure behavior between the screw cutting into bone and the SupraFusion implant augmenting the bone.