The control of porosity morphology and physico-chemical characteristics of calcium phosphate bone substitutes is a key-point to guaranty healing success. In this work, micro- and macroporosity of materials processed with 70% Hydroxyapatite (HAP) and 30% beta-tricalcium phosphate (beta-TCP) were controlled by sintering temperature and porogen addition, respectively. Porosity was quantified by scanning electron microscopy (pore size) and mercury intrusion porosimetry (interconnection between pores). The content of macrointerconnections and their size were dependent on porogen content, shape, and size. Mechanical properties (compressive strength) were strongly dependent on macroporosity size and content, on the basis of exponential laws, whereas microporosity ratio was less influent. Relying on those results, three types of materials with contrasting porous morphologies were processed and assessed in vitro, in primary culture of human osteoblasts and fibroblasts. With both types of cells, an exponential cellular growth was effective. Cells colonized the surface of the materials, bridging macroporosity, before colonizing the depth of the materials. Cell migration across and into macroporosity occurred via the emission by the cells of long cytoplasmic extensions that hanged on microporosity. Both macroporosity and macrointerconnectivity size influenced the penetration of cells. An interconnection size of 15 microm appeared to be effective to support this invasion without bringing down mechanical strength.

The purpose of this study was to compare two different strategies of management for ACL rupture in skeletally immature patient. In group 1, patients were treated in a children hospital by ACL reconstruction with open physis. In group 2, patients were treated in an adult hospital by delayed reconstruction at skeletal maturity assessed radiologically. Fifty-six consecutive patients were included in this retrospective study. Mean time from injury to surgery in group 1 and 2 was, respectively, 13.5 and 30 months. Patients from group 2 exhibited a higher rate of medial meniscal tears (41%) compare to group 1 (16%) and higher rate of meniscectomy. Both groups had the same rate of lateral meniscal tears. A temporary tibial valgus deformity was reported which was subsequently spontaneously resolved. No definitive growth disturbance was noticed. At 27 months mean follow-up, a best subjective IKDC score was found in group 1. Objective IKDC and radiological results were similar in both groups. Early ACL reconstruction is therefore a recommended option.

The purpose of the present study, based on 23 cadaveric knees, was to perform a detailed anatomical analysis of the medial patellofemoral ligament (MPFL), especially its femoral attachment, its relationships with the vastus medialis obliquus (VMO) and the medial collateral ligament, with the objective of improving its surgical reconstruction. The femoral insertion of the MPFL was defined using an orthonormal frame centered on the middle of the femoral MPFL insertion. The whole measurements were taken using a millimetric compass with a precision of +/-1 mm. The MPFL was always observed, its length was 57.7 +/- 5.8 mm, the junction between the VMO and the MPFL always present measured 25.7 +/- 6.0 mm. When it comes to MPFL reconstruction, the key point is its positioning in the femoral insertion because it is this insertion that is going to restore isometry. By using the orthonormal frame it has to be positioned 10 mm behind the medial epicondyle and 10 mm distal to the adductor tubercle.

Level IV. Retrospective study.