A force-compensated compliant MEMS-amplifier with electrostatic anti-springs.

In this paper, an electrostatic compliant mechanical amplifier intended for force-compensated displacement amplification in MEMS sensor applications is described. Usually, mechanical transformers that enhance a small input displacement into a large output displacement generate large forces at the input of the transformer. The microsystem proposed here allows for the reduction and compensation of the input stiffness of the amplifier and any mechanical components connected to it while providing a constant amplification ratio at the same time.

Use of the AO femoral distractor in revision total hip arthroplasty.

Use of the femoral distractor in trauma settings is well documented in the orthopedic literature. Use of the device extends into adult reconstructive surgery; surgeons use this distractor as an aid in performing difficult revision total hip arthroplasties (THAs). Patients with associated soft-tissue contractures secondary to subacute or chronic dislocation of a THA may present a clinical picture that might make consideration of simple open reduction only a remote possibility.