Is the pull-out force of the Meniscus Arrow in bone affected by the inward curling of the barbs during biodegradation? An in vitro study

Background: Inward curling of the barbs of Meniscus Arrows during degradation was observed in a previous study, in which swelling, distention, and water uptake by Meniscus Arrows was evaluated. This change of configuration could have consequences with respect to anchorage capacity in bone. Material/Methods: Eight non-degraded Meniscus Arrows in the original configuration were pulled out of thawed, fresh-frozen human femoral condyle, and pull-out force was measured and compared with that of 6 Meniscus Arrows after 31 days of degradation under controlled conditions. Results: No significant difference was found between the 2 groups with respect to the required pull-out force (t test), the distribution of the data, or the interaction between degradation and location, as evaluated by mann-Whitney test, and no significant difference was found between the 2 groups with respect to the degradation state or position in the coudyles, as evaluated by 2-way analysis of variance. Conclusions: Our results indicate that the decrease in barb-barb diameter during the first month of degradation of the Meniscus Arrows has no significant effect on the tensile pull-out force required for removal from human femur condyle. Further research should be undertaken to examine whether the same is true for other biodegradable devices with barbs.