Human Mesenchymal Stem Cell-derived Exosomes Promote Orderly Cartilage Regeneration in an Immunocompetent Rat Osteochondral Defect Model

Background : Although meniscal repair techniques have developed for several decades, meniscal repair of radial tears still remains challenging issue. For successful meniscal healing of radial tears, primary mechanical stability of meniscal repair is one of the essential requirements. All-inside vertical suture and Cross-suture techniques have been reported to provide superior stability compared to inside-out horizontal suture technique respectively. However, biomechanical comparison between vertical and Cross-suture technique in meniscal repair of radial tear was not performed yet. Purpose : The aim of this biomechanical study was to evaluate whether Cross-suture technique can show comparable stability to vertical suture technique in meniscal repair of radial tears. Material & Method: Biomechanical test was performed on matched paired 60 fresh-frozen porcrine menisci (3 groups, n=20 in each group). Complete radial tear was made at the midportion of each meniscus. In group A, menisci were repaired with parallel 2 stitch of insideout horizontal sutures for control. In group B, menisci were repaired with 2 stitch of insideout cross sutures. In group C, menisci were repaired with parallel 2 stitch of all-inside vertical sutures. Suture attachments were located at 5mm from the tear surface and 5mm and 10mm from the rim in all cases. The specimens were cyclically loaded 500 times between 5 and 20 N ,then gap of tear surface was measured. After completion of cyclic load testing, specimens were loaded to failure. Results : The mean maximum failure load were 72±15N(inside-out horizontal suture), 88± 20N(inside-out cross suture), and 105±27N(all-inside vertical suture). The mean displacement after a 500-cycle loading test were 5.23±1.82mm(inside-out horizontal suture), 4.56±1.87mm(inside-out cross suture), and 3.23±1.67mm(all-inside vertical suture). Cross suture technique showed significantly higher failure load compared with horizontal suture technique(p<.05). However, cross suture technique also showed significantly lower failure load(p<.05) and increased displacement(p<.05) compared with vertical suture technique. Discussion : In respect that both cross suture and vertical suture were superior to horizontal suture, our results matched with recent biomechanical studies which analyzed mechanical stability of horizontal suture technique, vertical suture technique, and newly suggested cross suture techniques. Also, new finding of our study was that vertical suture was superior to cross suture, as well as horizontal suture technique.