title: Comparison of four techniques for the fixation of a collagen scaffold in the human cadaveric knee.
abstract: OBJECTIVE
  Four fixation techniques for a fibrinogen and thrombin coated collagen fleece, used as a scaffold in the cartilage repair, were compared simulating the initial postoperative period in the cadaveric knee joints.
  
  
  METHODS
  Full-thickness chondral lesions were made on the medial femoral condyles of seven human cadaveric inferior extremities. Four scaffolds without seeded chondrocytes were implanted into each lesion using four fixation techniques consecutively: self-adhesion without additional material (SA), fibrin sealant (FS), bone sutures (BS), and periosteal cover (PC). After each implantation 150 cycles of continuous passive motion (CPM) were performed. Two cases were additionally exposed to 50 cycles of 10 and 20 kg loading each after the completion of CPM. The scaffolds were evaluated after every 30 cycles, and the fixation strength was tested after the motion was completed.
  
  
  RESULTS
  All the SA scaffolds were detached before 60 cycles. The other scaffolds remained stable throughout the testing with only minor disruptions. The endpoint fixation strength was higher for BS and PC than for the FS scaffolds. The FS scaffolds were detached as a result of additional load cycles, while the BS and PC scaffolds showed substantial deformations.
  
  
  CONCLUSIONS
  SA of tested scaffold did not provide sufficient fixation. The FS fixation was easy to perform and assured satisfactory scaffold stability. BS and PC provided excellent scaffold stability, but the techniques were difficult and caused additional injuries. Regardless of the fixation technique used, the tested collagen scaffold may not be exposed to loading in the initial postoperative period.
authors.affiliation: Department of Orthopaedic Surgery, University Medical Centre Ljubljana, Slovenia. matej.drobnic@mf.uni-lj.si
authors.forename: M
authors.initials: M
authors.lastname: Drobnic
authors.forename: D
authors.initials: D
authors.lastname: Radosavljevic
authors.forename: D
authors.initials: D
authors.lastname: Ravnik
authors.forename: V
authors.initials: V
authors.lastname: Pavlovcic
authors.forename: M
authors.initials: M
authors.lastname: Hribernik
mesh_terms: D000368:Aged; D002102:Cadaver; D002358:Cartilage, Articular / Q000601:surgery*; D003094:Collagen / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D013536:Suture Techniques / Q000592:standards; D013537:Sutures / Q000592:standards*; D014014:Tissue Adhesives / Q000592:standards*
chemical_list: D014014:Tissue Adhesives; D003094:Collagen