[Biomechanical considerations with Harrington traction and dorsal spondylodesis in double curved scoliosis].

The simple mechanical models and experimental spinal examinations could be established that the double curved scoliosis operated with two Harrington rods and dorsal spondylodesis is better than the use of one Harrington rod.

[Shear fracture stress of the spongiosa and pressure fracture stress of cortical bone of cadaveric vertebrae].

By biomechanic examinations of the vertebrae of human dead bodies the ultimate stress due to shearing (Schubbruchspannung) of the spongy substance could be found out with 1.80 N/mm2 and the ultimate stress due to compression (Druckbruchspannung) of the cortical-belonging to the thick of cortical--with 280 N/mm2. Both measuring results are important for the ultimate strength of the connection (Verankerungsfestigkeit) of screws in vertebae.

[Anchoring experiments on human cadaver vertebrae using various types of screws].

The firmness of the bone structure of vertebrae of human cadavers was investigated by turning screws of four different types into vertebrae T6 to L5 and subjecting them to axial tension up to the point of extraction. It was found that the cancellous bone screws (rather than the Zielke screw) had the best anchoring characteristics in bone tissue. The shearing fracture stress of the vertebral bone tissue was found to be approx.

[Static load on human cadaver femora with implanted hip endoprosthesis shafts in various forms].

The present paper deals with biomechanical investigations applying static pressures to endoprosthetic hip shafts implanted into cadaveric femora with bone cement. The purpose of the investigations was to observe the maximal breakload of the femora or endoprosthesis. We did experiments with 27 femora and implanted 4 different endoprostheses (3 metallic shafts and 1 ceramic shaft).