Autologous Mesenchymal Stromal Cells Immobilized in Plasma-Based Hydrogel for the Repair of Articular Cartilage Defects in a Large Animal Model.

The treatment of cartilage defects in trauma injuries and degenerative diseases represents a challenge for orthopedists. Advanced mesenchymal stromal cell (MSC)-based therapies are currently of interest for the repair of damaged cartilage. However, an approved system for MSC delivery and maintenance in the defect is still missing. This study aimed to evaluate the effect of autologous porcine bone marrow MSCs anchored in a commercially available polyglycolic acid-hyaluronan scaffold (Chondrotissue®) using autologous blood plasma-based hydrogel in the repair of osteochondral defects in a large animal model. The osteochondral defects were induced in twenty-four minipigs with terminated skeletal growth. Eight animals were left untreated, eight were treated with Chondrotissue® and eight received Chondrotissue® loaded with MSCs. The animals were terminated 90 days after surgery. Macroscopically, the untreated defects were filled with newly formed tissue to a greater extent than in the other groups. The histological evaluations showed that the defects treated with Chondrotissue® and Chondrotissue® loaded with pBMSCs contained a higher amount of hyaline cartilage and a lower amount of connective tissue, while untreated defects contained a higher amount of connective tissue and a lower amount of hyaline cartilage. In addition, undifferentiated connective tissue was observed at the edges of defects receiving Chondrotissue® loaded with MSCs, which may indicate the extracellular matrix production by transplanted MSCs. The immunological analysis of the blood samples revealed no immune response activation by MSCs application. This study demonstrated the successful and safe immobilization of MSCs in commercially available scaffolds and defect sites for cartilage defect repair.

Fixation of Knee Osteochondral Lesions in Pediatric Patients with Magnesium-Based Implants.

PURPOSE OF THE STUDY Fixation of osteochondral fragments are relatively common procedures in pediatric orthopaedic surgery. The use of biodegradable magnesium implants in these indications appears to be a promising alternative to polymer implants due to their favorable mechanical properties and biological behavior. The purpose of this study is to evaluate the short-term clinical and radiological outcomes of the fixation of unstable or displaced osteochondral fractures and osteochondritis dissecans lesions in the knee joint using MAGNEZIX® screws and pins in pediatric patients. MATERIAL AND METHODS In this study, 12 patients (5 girls, 7 boys) were included. The inclusion criteria were as follows (1) age below 18 years; (2) unstable or displaced osteochondral fragments secondary to trauma or as a result of osteochondritis dissecans, Grades III and IV in the ICRS (International Cartilage Repair Society) score, confirmed by imaging methods and indicated for surgical fixation; (3) fixation performed using screws or pins made of the magnesium-based MAGNEZIX® alloy; (4) minimum postoperative interval of 12 months. X-rays and clinical evaluation were assessed 1 day, 6 weeks, 3, 6, and 12 months after the operation. MRIs were performed 1-year postoperatively for evaluation of bone response and degradation behavior of implants. RESULTS The mean age at surgery was 13.3 ± 1.6 years. A total of 25 screws were used in 11 patients, a mean of 2.4 ± 1 per patient, 4 pins were used in 1 patient. In 2 patients, fixation with screws was complemented with fibrin glue. The mean follow-up was 14.2 ± 3.3 months. All patients exhibited complete functional recovery while showing no signs of pain at 6 months postoperatively. No adverse local reactions were observed. At 1-year follow-up, no implant failure has been reported. Complete radiographic healing occurred in 12 cases. Mild radiolucent zones were observed around the implants. CONCLUSIONS The use of screws and pins MAGNEZIX® has been found to provide satisfactory outcomes in terms of fracture healing and very good functional outcomes at 1 year postoperatively. Key words: biodegradable implants, magnesium-based implants, osteochondral fracture, osteochondritis dissecans, MAGNEZIX®.

Surgical treatment of fractures of the distal radius - ORIF vs external fixation with ligamentotaxis.

INTRODUCTION: The study compares the results of open reduction using volar locking plates with ligamentotaxis by external fixation in fractures of distal radius type 2R3C according to AO classification. METHODS: A retrospective study evaluating the results of osteosynthesis in patients with distal radius fractures type 2R3C according to AO classification, operated until December 2018. The ORIF method with volar locking plates (LCP) was used in 54 patients, and closed reduction with ligamentotaxis using external fixation (EF) was used in 33 patients. The mean age of the patients was 46.7 years in the LCP group and 59.6 years in the EF group. All were evaluated for their X-ray and functional outcomes and according to the Green and OBrien score at 6 and 12 months after surgery.  Results: According to X-rays at 12 months in the LCP group, the mean sagittal tilt was 10.13°, the mean radial inclination was 23.89°, and the mean radial length was 11.84 mm. In the EF group, the mean sagittal tilt was 6.32°, the mean radial inclination was 24.78°, and the mean radial length was 9.89 mm. According to the Green and OBrien score, we recorded a mean score of 84.44 points in the LCP group at 12 month; we achieved good and excellent results in 83.33% of the patients and no poor result was observed. In the EF group the final mean score was 77.27; good and excellent results were achieved in 45.46% of the patients and a poor result in one patient. CONCLUSION: Based on the results in our group of patients, the internal type osteosynthesis using LCP implants can be recommended as a first-choice technique in the treatment of 2R3C fractures according to AO classification.