Foundation® Knee System

Description

• Patello-Femoral Kinematics
  – The deepened patellar groove on the Foundation femoral component minimizes patellar advancement which has been shown to increase flexion ³ and restore normal kinematics.
  – Anatomic patellar groove promotes normal biomechanics.
  – Groove depth increases at higher angles of flexion to provide increased resistance to patellar dislocation.
  – The patello-femoral geometry of the Foundation Knee can resist lateral joint forces well beyond those seen in the physiological knee ⁵.
• Tibial Fixation: Solutions for Tibial Loosening

  Minimize the Transfer of Shear Stresses to the Underside of the Tibial Baseplate
  The Foundation tibial-femoral geometry was designed to allow the desired motion for a prosthetic knee which includes 8mm of rollback and +/-15° of rotation ⁷.

  Maximize Resistance to Shear Forces
  The tibial stem design utilizes the strongest bone in the proximal tibia to resist rotational forces design to provide maximum initial fixation and long term stability ^1,4,6.

  Optimize Load Distribution
  The asymmetric profile of the Foundation tibial components offers total coverage and uniform loading. These results are not thought to be achieved by symmetrical designs ².

References

1. Dempsey, A.J., Finlay, j.B., Bourne, R.B., Rorabeck, C.H., Scott, M.A., and Millman, J.C., Stability and Anchorage Consideration for Cementless Tibial Components, J. Arthoplasty 4:223-229, 1989.

2. Dupont, J.A.,Weinstein, A.M.,Townsend, P.R., Tibial Plateau Coverage inTotal Knee Replacement.Tenth coverage and Annua Meeting Soc. Biomaterials. Washington,D.C., April27-May1, 1984.

3. Moreland, J.R., Mechanism of Failure in Total Knee Arthoplasty, Clin. Orthop. 226:49, 1988.

4. Reily, D., Walker, P.S., Ben-Bov, M., Ewald, F.D., Efects of Tibial Components on Load Transfer in the Upper Tibia. Clin. Orthop. 165:274, 1982.

5. Steuben, C.M., Postak, P.D., Patelo-Femoral Resistance to Lateral Subluxation, Contact Areas and Surface Stress Distributions of the Foundation Total Knee System. Submitted to Encore Orthopedics, Inc., in February, 1993, by The Orthopaedic Research Laboratories, The Mt.Sinai Medical Center, Cleveland, Ohio.

6. Walker, P.S., Requirements for Sucesful Total Knee Replacements. Orthopedic Clinics of North America, Vol. 20, No.1, January,1989.

7. Yoshi, I., Whiteside, L.A., Anouchi,Y.S., The Effect of Patellar Button Placement and Femoral Component Design on Patellar Tracking in Total Knee Anthroplasty. Clin. Orthop. and Rel. Res, 275:211-19.