Plate-screw-wiring technique for the treatment of periprosthetic fracture around the hip: a biomechanical study.

Biomechanic properties, bending stiffness and torsional strength, were determined in three different fixation techniques including lateral plating, lateral plating with cerclage wires, and 90 degrees-90 degrees anterior and lateral plating employed in treatment of the femoral shaft fracture with the presence of a femoral prosthesis. Five pairs of human femora with a man made cemented periprosthetic Johansson et al fracture classification type II were used in the experiments. The study showed that 90 degrees-90 degrees anterior and lateral plating produced the best increment in both biomechanic properties. In clinical practice, most of the soft tissue around femoral bone had to be dissected to do this technique, which would affect bone healing. Further study regarding the other properties, benefits, and disadvantages of these three techniques should be conducted before selecting the best method for treatment of the patients.

The biomechanical study of atlantoaxial fixation.

Recent studies of various C(1-2) constructs have confirmed superior stability with transarticular screw fixation. In the meantime, our study on the C2 morphology in Thai people found about 4 per cent of the pedicles were too small for the 3.5 mm. C(1-2) transarticular screw. In order to select a smaller screw to use in this operation, we performed a biomechanical testing of 2 sizes of screw (2.7 mm, 3.5 mm) for transarticular screw fixation and Gallie's wiring, comparison in terms of stiffness in flexion, extension, torsion, anterior and posterior shear loads. There were no statistical differences of the stiffness between 2.7 mm and 3.5 mm transarticular screw fixation in all directions, whereas there were significantly greater stiffness of transarticular screw over Gallie's wiring in various directions (P<0.05).

Allograft replacement in limb salvage surgery for bone tumors.

A retrospective study of a series of eleven patients with active, aggressive benign and malignant bone tumors who were treated by radical resection and massive match-sized allograft replacement was reviewed. There were seven giant cell tumors and four osteosarcoma cases involving mainly either the lower end of the femur or upper end of the tibia. The age of the patients ranged from 11 to 50 years. As the follow-up period was rather short, ranging from 9 to 60 months, the patients are all still alive. Complications included two infections, one local recurrence, and two with resorption of the articular surface of the osteoarticular graft. Though psychosocial benefit was gained in patients with this limb salvage procedure, functional evaluation did not yield a satisfactory result.