Introduction: Treatment of choice in osteogenesis imperfecta (O.I.) patients presenting severe deformities of lower limbs is endomedular nailing with previous corrective osteotomy. Fassier-Duval telescopic rod permits anterograde nailing without the need of distal arthrotomy and thus, joint damage.

MATERIAL AND Methods: We retrospectively revised the first 14 rods implanted in 9 patients at our service, 6 males and 3 females. Average age of 6.14 years. Sillence type III: 5, type IV: 4. Six right femurs, 7 left femurs and one tibia were nailed. In 5 of the 14 cases surgery was performed on acute fractures on previous deformities, in 9 cases because of progressive deformities. Corrective osteotomies were performed in all cases. Seven of 9 patients were receiving treatment with palmidronate prior to surgery. Improvement in quality of life with Bleck scale was assessed.

Results: Six of 14 operations were salvage procedures because of failure of other implants. Complications included a transient sciatic palsy, lack of telescoping in one case, one acute fracture with implant failure and one delay in consolidation. Two reoperations were needed. Global Bleck score improved from 7.37 to 12.75 (p=0.024), walking score improved from 1.25 to 2.87 (p=0.038).

DISCUSSION AND Conclusions: Fassier-Duval telescopic rod is a safe and useful implant for the treatment of deformities in the lower limbs in patients with O.I. There was a significant improvement in both global quality of life score and walking score.

Our aim was to evaluate the expression of transcription factors CCAAT/enhancer-binding protein-beta (C/EBP_β) and C/EBP-homologous protein (CHOP) in the growth plate. Proximal tibial epiphyseal growth plates from ten 15-day-old Wistar rats were used. Additionally, anti-proliferating cell nuclear antigen (PCNA), anti-5-bromo-2’-deoxyuridine (BrdU) immunostaining, terminal transferase dUTP nick end-labelling (TUNEL) and nucleolar organiser region-associated proteins (AgNOR) techniques were peformed. The histological morphology of the growth plate from C/EBP_βknock-out mice was also analysed.

The normal growth plate showed that C/EBP_β and CHOP factors are expressed both in the germinative/ upper proliferative and in the lower proliferative zones. Furthermore, BdrU+ and PCNA+ cells were present exclusively in the germinative and proliferative zones, while TUNEL+ and AgNOR+ cells were seen in all three zones of the growth plate. Acellular areas, hypocellularity, the increase in cell death and anomalies in the architecture of the cell columns were observed in the growth plates of C/EBP_β (−/ −) knockout mice.

We suggest that C/EBP_β and CHOP transcription factors may be key modulators participating in the chondrocyte differentiation process in the growth plate.