Compress Compliant Pre-Stress Implant

The Compress Compliant Pre-Stress Implant makes use of stored energy to snap the extramedullary portion of the prosthesis to the native bone. Proximally, an anchor plug is fixed to the native bone via transverse (anti-rotation) pins and connected to an intramedullary traction bar. The bar extends out through the spindle and is loaded with Belleville washers (washer-shaped springs). A nut is tightened at the end of the traction bar to achieve the desired compression of the spindle against the bone.

This compression acts to induce bone hypertrophy, reduce stress shielding seen in stem prostheses, and seal the medullary canal from particulate debris that can cause osteolysis.

The short length of the device allows placement of a prosthesis with as little as 46 mm of bony canal.

References

Bhangu AA, Kramer MJ, Grimer RJ, O'Donnell RJ. Early distal femoral endoprosthetic survival: cemented stems versus the Compress implant. Int Orthop. 2006 Dec;30(6):465-72.