The Hype of Mobile Bearing Knees

The Hype of Mobile Bearing Knees

2012 AAOS

Mobile bearing vs. fixed bearing TKA; no difference with more than 10 years

  1. Theoretical advantages; better range of motion/clinical function/patellofemoral mechanics.
  2. Less polyethylene wear/osteolysis.
  3. Longer clinical durability of implants.

Although there are many historical comparison studies that have attempted to prove these claims, the use of randomized clinical trials and literature meta-analysis have repeatedly demonstrated no superiority of either design in any of these areas of theoretical advantage.

Kim, 2010, at 12-year follow-up the incidence of osteolysis, rate of revision, and implant survivorship were similar between the fixed bearing and mobile bearing TKAs in younger patients.

There are no (RCTs) randomized clinical trials or literature meta-analysis that suggests any superiority of durability with either design in the first two decades of clinical use. Based on all the available clinical evidence there is no demonstrated advantage when evaluating range of motion, clinical function, wear, osteolysis, or long-term durability of the rotating platform mobile bearing TKR design when compared with a fixed bearing design.

Long-term comparison of fixed and mobile-bearing TKAs in patients younger than 50 years of age.
Author: Kim et al.

Prospective randomized comparison of fixed and mobile-bearing total knee designs in the same patients with osteoarthritis younger than 50 years of age is limited.

... patients with osteoarthritis younger than 50 yrs of age who received a fixed-bearing prosthesis in one knee and a mobile-bearing knee in the other.

Conclusion: We found no evidence to prove the superiority of mobile-bearing over fixed-bearing total knee arthroplasty

2012 American Academy of Orthopedic Surgeons (AAOS) Meeting – San Francisco; selected excerpts.

-JGM