Knee Implants

About Medial-Pivot Knee Design

Because traditional knee replacements are not designed like a normal knee, they do not perform like a normal knee. But MicroPort Orthopedics’ proprietary medial-pivot design is more complex than other implants; it pivots on its inner (medial) side. And, when the knee bends, the outer (lateral) side rolls back, while the medial side rotates in one place.

This unique ball-in-socket mechanism provides stability where traditional implants slide forward1, 2. And ball-in-socket knees have also been shown to produce greater range of motion than traditional posterior stabilized knees and have a femoral rollback profile similar to the normal knee3. Our medial-pivot implants replicate the motion and stability of a healthy knee by bending, rotating and twisting, while maintaining complete control.

About the Evolution®MP Knee System

MicroPort Orthopedics’ Evolution®MP Knee System offers three medial-pivot knee designs:

  • Cruciate-Substituting (CS)
  • Cruciate-Retaining (CR)
  • Posterior Stabilized (PS)

Although each offers unique benefits, all three incorporate spherical femoral condyles which match a conforming medial socket to create a ball-in-socket concept. Each design also boasts a lateral surface which allows for mixed rolling and spinning to occur in a 15° arcuate path. And all Evolution®MP Knee implants are designed to preserve as much of the body’s natural structure as possible through tissue-sparing procedures that may reduce recovery time.


  1. Dennis DA, Komistek RD, Mahfouz MR, Haas BD, Stiehl JB. “Multicenter determination of in vivo kinematics after total knee arthroplasty,” Clinical Orthopaedics and Related Research. 2003.
  2. Schmidt R, Komistek RD, Blaha JD, Penenberg BL, Maloney WJ. “Fluoroscopic analyses of cruciate-retaining and medial-pivot knee implants,” Clinical Orthopaedics and Related Research. No. 410:139-147.
  3. Hossain. et al. ”Knee Arthroplasty with a Medially Conforming Ball-and-Socket Tibiofemoral Articulation Provides Better Function” Clinical Orthopaedics and Related Research. 2010 Aug 11. [Epub ahead of print].


Individual results and activity levels after surgery vary and depend on many factors including age, weight and prior activity level. There are risks and recovery times associated with surgery and there are certain individuals who should not undergo surgery. Please click here to read about risks associated with surgery. Only a physician can tell you if this product and associated procedure are right for you and your unique circumstances. Please consult with a physician for complete information regarding benefits, risks and possible outcomes.