Tomáš Trč

Novel composite hyaluronan/type I collagen/fibrin scaffold enhances repair of osteochondral defect in rabbit knee.

A new composite scaffold containing type I collagen, hyaluronan, and fibrin was prepared with and without autologous chondrocytes and implanted into a rabbit femoral trochlea. The biophysical properties of the composite scaffold were similar to native cartilage. The macroscopic, histological, and immunohistochemical analysis of the regenerated tissue from cell-seeded scaffolds was performed 6 weeks after the implantation and predominantly showed formation of hyaline cartilage accompanied by production of glycosaminoglycans and type II collagen with minor fibro-cartilage production. Implanted scaffolds without cells healed predominantly as fibro-cartilage, although glycosaminoglycans and type II collagen, which form hyaline cartilage, were also observed. On the other hand, fibro-cartilage or fibrous tissue or both were only formed in the defects without scaffold. The new composite scaffold containing collagen type I, hyaluronan, and fibrin, seeded with autologous chondrocytes and implanted into rabbit femoral trochlea, was found to be highly effective in cartilage repair after only 6 weeks. The new composite scaffold can therefore enhance cartilage regeneration of osteochondral defects, by the supporting of the hyaline cartilage formation.

Manipulation of pediatric supracondylar fractures of humerus in prone position under general anesthesia.

Background: Displaced pediatric supracondylar fractures are usually treated with manipulation and fixation with Kirschner wires. The procedure is commonly performed with the patient in supine position. Reducing and stabilizing the fracture with the patient in supine position are associated with various risks and technical difficulties. Methods: We describe a technique of manipulative reduction and fixation of pediatric supracondylar fractures by positioning the patient prone. Results: We have used this technique in 455 patients and prefer it to the commonly described method of fracture reduction and stabilization with the patient supine. Conclusions: Positioning the patient prone simplifies the reduction and provides adequate exposure to insert Kirschner wires safely from both medial and lateral aspects. Positioning the C-arm is easily achieved, and good radiographs are obtained without disturbing the reduced fracture. Level of Evidence: Level III.

Correlation of dynamic impact testing, histopathology and visual macroscopic assessment in human osteoarthritic cartilage

Objective Improved staging of cartilage degeneration is required, particularly during the early stages. We correlated mechanical properties with histological and macroscopic findings.MethodsOne hundred and twenty cartilage samples were obtained during total knee arthroplasty. Two adjacent plugs were harvested—one for histological classification and one for macroscopic and biomechanical purposes. Dynamic impact testing was performed; normal stress, dissipated energy (∆E), tangent modulus and stiffness were evaluated. Results Samples were classified according to six categories of the ICRS histological scale. Mechanical characteristics revealing significant differences between the groups (p < 0.01) were specific damping and related absolute ∆E. A significant correlation was found between the macroscopic score and specific damping, as well as absolute and relative ∆E (p < 0.01). A strong relation was revealed between relative ∆E and cartilage thickness (p < 0.001; R2 = 0.69). Conclusions Only ∆E correlated with the condition of the cartilage—the value increased with decreasing quality—and is the most suitable characteristic. This change appears substantial in initial stages of cartilage deterioration.

Retrieval of New Characteristic Features for Description of Cartilage Tissue Properties Using Blunt Impact Testing Approach

Investigation of joint cartilage properties is of prime importance due to facilitation of its routine diagnostics and artificial tissue engineering. This experiment is based on our previous work in which we have developed new technique for dynamic testing of cartilage tissue biomechanical properties using blunt impact approach. Obtained data are confronted with ICRS histological classification of examined knee cartilage samples.