In Vitro Effects of PDGF Isoforms (AA, BB, AB and CC) on Migration and Proliferation of SaOS-2 Osteoblasts and on Migration of Human Osteoblasts.

PDGF is a major constituent of platelet rich plasma (PRP), responsible of chemotactic and possibly of mitogenic effects of PRP on osteoblasts. PDGF family includes 5 isoforms: PDGF-AA, PDGF-AB, PDGF-BB, PDGF-CC and PDGF-DD, all expressed in platelets except PDGF-DD. Aim of this study was to analyze the effect of recombinant hPDGF-A, -AB, -B and -C, on migration and proliferation of a human osteoblastic cell line, SaOS-2. Preliminary observations on cell migration were also done in primary cultures of human osteoblasts. In vitro microchemotaxis and (3)H-thymidine mitogenic assays were used. While PDGF-AB is active at concentrations present in PRP, PDGF-AA and BB are chemotactic only at much higher doses. PDGF-C is totally inactive alone or together with the active isoforms. PDGF-AA, PDGF-BB and PDGF-C stimulate SaOS-2 proliferation only at the highest dose tested, while PDGF-AB is ineffective. Primary osteoblasts are less sensitive than SaOS-2 and progressively lose responsiveness with increasing passages in culture, in line with loss of cell differentiation. The different PDGF isoforms act differentially on osteoblasts, the-AB isoform appearing the major responsible of the PRP chemiotaxis. PDGF, at the concentrations present in PRP, does not affect cell proliferation.

Percutaneous compression plating versus gamma nail for the treatment of pertrochanteric hip fractures.

The objective of this study is to compare percutaneous compression plating (PCCP) device with standard gamma nail (GN). A sample was prospectively followed and compared to a historical cohort: 82 intertrochanteric hip fractures in 81 patients treated with PCCP in 2004 versus 51 hip fractures treated with GN in 2003 (AO type 31A1, 31 A2). The main outcome measures were: surgery times, blood loss (Hb serum level and transfusions), complication, costs, for a 1-year follow-up. The minimally invasive PCCP technique resulted in a lower blood loss and consequently lower transfusion need (statistically significant), fewer implant-related complications and comparable surgery times. Overall surgical costs were lower for a comparable outcome in terms of healing and surgical time.