The treatment of infantile Blount's disease remains controversial. The progressive development of epiphysiodesis of the medial tibial physis induced a complex deformity of the lower limb such as severe genu varum, joint incongruity, torsion instability and leg length discrepancy with major functional consequences. Nine knees on eight children (average age was 7 years and 2 months) were treated by a one-time procedure using a specific external fixator that combined elevation of the medial tibial plateau, axial correction in the valgus, complete sterilization of the upper tibial growth cartilage, leg lengthening anticipation and de-rotation if necessary. Magnetic resonance imaging was useful to describe the deformity and to prepare for surgery. Corrections were progressively obtained through the physis plan by means of short incisions and the use of a specific external fixator. The primary results at an average of 24 months were good with a low rate of complications but final evaluation will be conducted at the end of the children's growth period.

Three different exoskeletons of coral species Porites asteroides (P), Montastrea annularis (M), and Dichocoenia stokesi (D) were implanted for 2-20 weeks in rabbits. At 2, 4, 8, or 20 weeks, the exoskeletons presented variations in their resorptions depending on the species. To understand the variations in the decreasing speed of the implants despite their similar chemical composition, a study of the surface and architecture of the coral was carried out using scanning electronic microscopy, porosity was evaluated, and growth and differentiation of osteogenic cells cultured in vitro were observed for more than 1 month. At the cellular level, the surface of the implants was identical. Three-dimensional structures of the implants were variable, but the porosity values [P = 42.7%, M = 40.7%, and D = 17.4%] could not completely account for the differences in the resorbing process of the species. Standard histologic studies performed at 2, 4, 8, and 20 weeks after implantation produced the same pattern with P or M, showing aspects of rapid resorption; however, with D there were images resembling those of a foreign-body reaction. It seems that when resorption is not quick enough, a foreign body reaction develops which further slows down the process. This work focuses on the importance of porosity when using coral as bone substitute.

Level IV, retrospective study.

No abstract

IV: Systematic revue of the literature.