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

The arthroscopic treatment of displaced tibial spine fractures in children and adolescents using Meniscus Arrows®

This article summarises the results of a newly developed technique that utilises Meniscus Arrows(A (R)) for the arthroscopic fixation of displaced tibial spine fractures in children and adolescents. Twelve tibial spine fractures in the knees of eleven children between 6 and 15 years old, with an average age of 12 years, were arthroscopically fixed with Meniscus Arrows(A (R)), after a reduction of their fractures. This was followed by 5 weeks immobilisation in a plaster of Paris. Postoperative follow-up included radiographs, Lachmann tests on all of the children's knees and KT-1000 tests of eight out of twelve of the children's knees. The postoperative follow-up time ranged from 3 to 10 years, with patients being seen for an average of 4 years. All of the fractures consolidated uneventfully, and all of the patients returned unrestricted to their previous activity level. The Lachmann tests revealed no, or a non-functional, laxity in any of the patients' knees. The KT-1000 tests showed a difference between the operated side, and non-operated side, of between 3 mm in the first knee operated on and an average of 1 mm in the remaining knees. The arthroscopic fixation of tibial spine fractures using Meniscus Arrows(A (R)) showed that this minimally invasive procedure resulted in the uneventful consolidation of all twelve of the fractures, with excellent results, and without the need for a second, hardware removal, operation. Level of Evidence: Level IV

Fixation of osteochondral fragments in the human knee using Meniscus Arrows®

The aim of this study is to compare the hold in bone of Meniscus Arrows® and Smart Nails®, followed by the report of the results of the clinical application of Meniscus Arrows® as fixation devices. First, pull-out tests were performed to analyse the holdfast of both nails in bone. Statistical analysis showed no significant difference; therefore, the thinner Meniscus Arrow® was chosen as fixation device in the patient series of two patients with a symptomatic Osteochondritis dissecans fragment and three patients with an osteochondral fracture of a femur condyle. The cartilage margins were glued with Tissuecoll®. All fragments consolidated. Second look arthroscopy in three patients showed fixed fragments with stable, congruent cartilage edges. At an average follow-up period of 5 years no pain, effusion, locking, restricted range of motion or signs of osteoarthritis were reported. Based on the results of the pull-out tests and available clinical studies, Meniscus Arrows® and Smart Nails® are both likely to perform adequately as fixation devices in the treatment of Osteochondritis dissecans and osteochondral fractures in the knee. They both provide the advantage of one stage surgery. However, based on their smaller diameter, the Meniscus Arrows® should be preferred for this indication

Will the hold of solid biodegradable implants be influenced by swelling during the degradation process?

Water uptake after implantation of biodegradable devices induces swelling, as mentioned in literature. The hold in bone of solid devices will increase if the swelling is substantial enough. The results of weighing six Meniscus Arrows (R) (MAs) before and after immersion in a sterile phosphate buffered saline solution during different time intervals were compared with the outcome of measurements under a field emission scanning electron microscope of six other MAs, stored under comparable conditions. The data were statistically evaluated with the Wilcoxon's signed rank test. The weight increase of 2.1 mg or 9.16% was statistically significant in the first 2 h following immersion, remaining stable afterwards with an average weight gain of 1.7 mg or 7.18%. The core diameter of the MAs increased to 0.01 mm or 1.01% with time. Although this is statistically significant, it is not expected to have any consequences for the hold. However, a remarkable and statistically significant decrease in the outer inter-barb diameter of 0.15 mm or 8.6% was noted with time. Mechanical testing should reveal the clinical relevance of the results of this study

Immunological Properties of Inulin-Type Fructans

Beneficial effects of inulin-type fructans are discussed in view of studies that applied the oligosaccharides in colon cancer, chronic inflammatory diseases, vaccination efficacy, and prevention of infection and allergy. In the present paper, we discuss their immunomodulating effects. It is suggested that immunomodulation is elicited through indirect and direct mechanisms. Indirect mechanisms encompass stimulation of growth and activity of lactic acid bacteria, but can also be caused by fermentation products of these bacteria, i.e., short chain fatty acids. Evidence for direct effects on the immune system generally remains to be confirmed. It is suggested that inulin-type fructans can be detected by gut dendritic cells (DCs), through receptor ligation of pathogen recognition receptors (PRRs) such as Toll-like receptors, nucleotide oligomerization domain containing proteins (NODs), C-type lectin receptors, and galectins, eventually inducing pro- and anti-inflammatory cytokines. DCs may also exert antigen presenting capacity toward effector cells, such as B cells, T cells, and natural killer cells locally, or in the spleen. Inulin-type fructans may also ligate PRRs expressed on gut epithelium, which could influence its barrier function. Inulin-type fructans are potent immunomodulating food components that hold many promises for prevention of disease. However, more studies into the mechanisms, dose-effect relations, and structure-function studies are required