Immunohistochemical study of angiogenesis after local administration of platelet-rich plasma in a patellar tendon defect.

A full thickness defect was made in the central portion of the patellar tendon of 48 New Zealand white rabbits. Platelet-rich plasma (PRP) gel was then applied and filled the tendon defect. The same procedure was performed in the control group, without the application of PRP. Animals were sacrificed after one, two, three, and four weeks. Histological and immunohistochemical analyses using a monoclonal antibody against CD31 were performed. The histological examination showed a superior healing process in the PRP group compared with the control group. Especially in the third week, the tissue formed in the PRP group was more mature and dense with less elastic fibres remaining. Neovascularisation was significantly higher in the PRP group during the first two weeks and significantly lower in the third and fourth weeks (p < 0.0001). Histological examination and study of angiogenesis showed that the application of PRP enhances and accelerates the tendon healing process.

Comparative study of 5 different membranes for guided bone regeneration of rabbit mandibular defects beyond critical size.

BACKGROUND: Although several studies have examined use of collagen membranes in guided bone regeneration (GBR), none has examined the use of human fascia temporalis as a bioabsorbable barrier. The majority of studies related to GBR have examined critical size defects. We sought to assess the human fascia temporalis and other well-documented membranes applied for GBR in mandibular osseous defects beyond critical size. MATERIAL/METHODS: Fifty adult male New Zealand white rabbits were used in this study. Five groups of 10 animals each were used: HFL (human fascia lata membrane), HP (human pericardium), HFT (human fascia temporalis), BP (bovine pericardium), and PTFE (expanded polytetrafluoroethylene). Animals were killed 10 weeks after membrane application. In each animal, 9-mm circular mandibular defects were created bilaterally. On 1 side of the jaw, the defect was covered with 1 of the test membranes; the defect on the other side served as a control. Harvested specimens were examined histologically. RESULTS: Membranes were significantly superior to the controls in all animals (P<0.001). Paired comparisons showed that groups HFL, HP, BP, and PTFE were significantly superior to HFT (P<0.05). Conversely, comparisons of HFL-HP, HFL-BP, HFL-PTFE, HP-BP, HP-PTFE, and BP-PTFE, showed no significant differences (P>0.05). CONCLUSIONS: According to our results, the fascia temporalis is not recommended for GBR techniques. The fascia lata, human pericardium, bovine pericardium, and e-PTFE advance bone regeneration and can be successfully used as GBR membranes for osseous defects beyond the critical size.

External fixation of intertrochanteric fractures in elderly high-risk patients.

This study concerns 56 elderly high-risk patients with an intertrochanteric fracture of the femur, who were treated with the Citieffe/Ch-N external fixator between November 2002 and February 2004. A short intraoperative time (37 minutes), no need for peroperative blood transfusion, fast mobilisation and a short hospitalisation (average 6 days, thus reducing the total cost) were noted. Union was obtained in all patients after 6 months. There was no significant difference between the functional status before the injury and at follow-up after 12 months (p > 0.05). No deep pin track or wound infections occurred, but a superficial skin reaction was seen in 39.3%. The mortality rate was 16.1% at 6 months, and 20.4% at 12 months, which contrasts favourably with other types of treatment. External fixation with this device can be used successfully for the treatment of elderly high-risk patients with intertrochanteric fractures.