ABSTRACT
OBJECTIVE@#To compare and analyze the mechanical differences between single-row suture anchor fixation for repairing rotator cuff injuries and double-row suture bridges for repairing rotator cuff injuries from a biomechanical perspective.@*METHODS@#The CT scan data of healthy adult shoulder joint were imported into Mimics, Geomagics and Hypermesh to carry out reverse reconstruction of two repair models, material assignment and mesh division, and the tearing of supraspinatus muscle was designed. After treatments, the load and boundary conditions were applied to the shoulder joint in ABAQUS software. The shoulder joint was fixed with four working conditions including flexion 15 °, flexion 30 °, internal rotation 15 ° and internal rotation 30 ° after anchor fixationand repair. The stress changes of the upper rotator cuff muscle and the anchor with thread were compared under these four conditions.@*RESULTS@#Under the two flexion conditions, the stress of the supraspinatus in the double row suture bridge fixation model was 8.3% and 12% less than that in the single-row suture anchor fixation, respectively. Under the two internal rotation conditions, the stress of supraspinatus in the double row suture bridge fixation model was 47% and 48% less than that in the single row fixation repair model, respectively.@*CONCLUSION@#The "load sharing" effect between the two rows of four anchors makes the stress distribution more dispersed, increases the contact area between the supraspinatus muscle and the humerus, reduces the stress of the anchor, avoids the serious stress concentration phenomenon, and explains the advantages of the fixation method of the double row suture bridge from the biomechanical angle.
Subject(s)
Adult , Humans , Biomechanical Phenomena , Cadaver , Rotator Cuff Injuries/surgery , Suture Anchors , Suture Techniques , SuturesABSTRACT
BACKGROUND: Preliminary experiments have confirmed that poly(hydroxybutyrate-co-hydroxyoctanoate) (PHBHOx)/collagen composite osteochondral scaffold exhibits desirable pore structure and biocompatibility. OBJECTIVE: To investigate the effect of PHBHOx/collagen composite osteochondral scaffold carrying bone marrow mesenchymal stem cells in the repair of articular osteochondral defects in the weight-bearing area of rabbits. METHODS: Cone-shaped osteochondral defects were created in the femoral medial condyle of the right knee of 30 New Zealand white rabbits. Then, the rabbit models were randomized into three groups and underwent implantation of PHBHOx/collagen composite osteochondral scaffold carrying bone marrow mesenchymal stem cells in the scaffold-cell group, PHBHOx/collagen composite osteochondral scaffold in the scaffold group and no intervention in the control group. At 4 and 12 weeks after surgery, animals were sacrificed for gross, Micro-CT, histological and immunohistochemical collagen II observations. RESULTS AND CONCLUSION: At 12 weeks after surgery, Micro-CT scanning results suggested that osteochondral defects were not repaired in the control group, repaired incompletely in the scaffold group with many new bone trabeculae, and repaired completely in the scaffold-cell group. Histological results showed that at 4 weeks after surgery, the defects in the control group were filled with amorphous tissues, subchondral bone formation just occurred in the scaffold group but increased in the scaffold-cell group. At 12 weeks after surgery, trabecular bone structure with no cartilage lacuna was observed in the control group; incomplete subchondral bone formation was observed in the scaffold group, and the cartilage layer was repaired by the fibrous tissues; in the scaffold-cell group, osteochondral defect repair was complete, with the emergence of tidal line, and the newborn cartilage was completely integrated with the surrounding normal tissue in addition to a similar thickness. At 12 weeks after surgery, collagen II basically did not express in the control group, weakly expressed in the scaffold group and highly expressed in the scaffold-cell group. In short, the PHBHOx/collagen composite osteochondral scaffold promotes the repair of articular osteochondral defects in the weight-bearing area.