Background. Tibial pilon fractures lead to complicated therapeutic problem. Application in these cases of external fixators which are composed of an active articulated joint hinge imitating movement in the region of upper ankle joint, which allows plantar and dorsal flexion, leads to functional treatment of distal tibia fractures.

Aim. The aim of the study was to present the four year experience with an evaluating biomechanical parameters, medical properties and clinical usefulness of the external fixator Dynastab-S in the treatment of tibial pilon fractures.

Material. Observations were based on patients hospitalized in Orthopedic and Rehabilitation Department of Medical University of Warsaw in a period from March 2000 to August 2004. The average period of observations was 29 months. Inclusion criteria were based on the algorithm which was created in our department.

Results. The assessment of biomechanical parameters of bone-fixator arrangement proved usefulness and safeness of the external fixator Dynastab-S. The positive results of clinical examinations, X-ray examinations and subjective opinion of the patients encourages to wide use of the external fixator Dynastab-S in the treatment of tibial pilon fractures.

Aims: The purpose of this work is to present regenerative potential of bone marrow-derived mesenchymal progenitor cells (MPC) combined with biodegradable matrices in goat knee osteochondral defect. Methods: Adult goat’s bone marrow aspirates where fractionated and adherent cultures were established. After two weeks of culture, nearly confluent cells were detached and resuspended to concentrations of 10 x 106 cells/mL. Cells were loaded onto PGA-PLLA scaffolds with negative pressure to allow uniform distribution. Such autologous constructs were incubated and than implanted into osteochondral knee defects. Empty scaffolds served as a control in contralateral knee. At the time of implantation (time “zero”), replicate scaffolds were evaluated for histological appearance. After 4 and 12 weeks, implants were removed and evaluated by the tissue scoring system. Results: Time “zero” histology revealed uniformly distributed cells. At 4-week time point implants did not exhibited satisfactory integration with surrounding tissue, and most of the upper tissue was the type of hyaline-like cartilage. At 12-week time point, most of the upper tissues were hyaline-like cartilage, while lower parts were filled with bone, however not all of them showed good integration. Conclusions: The results of this work revealed osteochondral potential of autologous MPC in goat cartilage defect. It is clear, that further studies are needed to improve integration of scaffolds with surrounding tissue.