Currently, this is how I would summarize the pros and cons of the two devices.

Uncemented MoM HRA (Zimmer-Biomet Recap/Magnum)

• Proven technology with the best long-term outcomes in the world for ANY type of hip surgery: 98% 18-year KM implant survivorship in over 6000 cases with 90% patient UTD follow-up.
• Femoral fixation uncemented proven better for patients with soft bone, large bone defects including osteonecrosis.
• Cobalt release. No cases of AWRF since 2009. However, 20% have mildly elevated cobalt levels which may be a source of anxiety for some patients and may lead to unnecessary revision surgery by uninformed surgeons.

Hybrid MoP HRA (Exactech Polymotion)

• Projected lower cobalt release hopefully would bring all HR patients into the normal range of cobalt for patients without implants.
• The socket component comes with supplemental fixation pegs, that should eliminate any cup shifts postoperatively (occurs in 1% of Magnum cups).
• Cemented femoral component. In the expert surgeon series of HRA with the BHR (cemented femur) implant, 10-year implant survivorship is similar to my results with the uncemented Recap/Magnum in men with osteoarthritis. There is evidence to suggest that a cemented femoral component has a higher failure rate in the following patient categories:
  • weak bone (if femoral neck T-score <-1.5)
  • osteonecrosis (large segments of dead bone in the head)
  • Large head cysts from osteoarthritis.
• The plastic socket is far more flexible than the metal Magnum. Therefore, I would suspect that it would have a higher failure rate in cases with large segmental socket defects (moderate to severe dysplasia, legg-perthes, severe socket wear in OA).