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 condyles, 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.