Posterior transosseous capsulotendinous repair in total hip arthroplasty : a cadaver study.

BACKGROUND: While recent clinical articles have reported a dramatic reduction in rates of total hip dislocation after posterior transosseous repair, we are not aware of any published biomechanical data to support this finding. The objectives of this study were to investigate the functional anatomy of the posterior transosseous repair and its effect on stability after total hip replacement. METHODS: Six total hip prostheses were implanted into three fresh cadavera. Three different repair situations (no repair, soft-tissue repair, and transosseous fixation) were then consecutively tested on each hip. Values for torque resistance and the angular range of motion at dislocation were recorded. Each repair was tested twice, yielding a total of thirty-six torque values and thirty-six angles of rotation. RESULTS: The transosseous repair was superior with regard to both torsion strength (four times stronger than that after no repair [p = 0.0002] and more than twice as strong as that after soft-tissue repair [p = 0.002]) and the magnitude of the angle of rotation observed prior to dislocation (an increase of 83% in comparison with that after no repair [p = 0.0005] and an increase of 46% in comparison with that after soft-tissue repair [p = 0.004]). CONCLUSIONS: In a cadaver model, posterior transosseous repair provides superior stability of a total hip replacement. Optimal surgical technique with a slightly modified approach allows greater retention of capsule and tendon length and a more anatomical reinsertion of the soft tissues

Fatigue related electromyographic median frequency characteristics of back and hip muscles during isometric back extensions

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Influence of bone milling parameters on the temperature rise, milling forces and surface flatness in view of robot-assisted total knee arthroplasty

The authors have developed a robot-assisted procedure to prepare the tibial surface in total knee arthroplasty (TKA). Using hybrid force/velocity control, the surgeon machines the bone by means of an end mill attached to the robot-arm. The milling forces can give information on the local bone quality intra-operatively. This paper describes experiments on human tibial bone to analyse the influence of the feed rate and the milling speed on the temperature rise, the milling forces and the surface flatness. © 2001 Elsevier Science B.V.status: publishe