All-polyethylene tibial components may lower surgical costs vs metal-backed components

Robert T. Trousdale, MD

The article entitled “All-polyethylene tibia: An opportunity for value-based care and bundled reimbursement initiatives” by Shawn P. Ryan, MD, and colleagues is a nice summary of the early cost advantages of an all-polyethylene tibial component vs. a modular tibial base plate. The authors have nicely shown that use of an all-poly tibia provides marked savings and decreases total hospital cost. They documented that there was no difference in 90-day ED visits or readmissions between the two groups.

This article nicely showed that there is some value and cost-savings opportunity when using an all-polyethylene tibia. There are a few issues with the data. The two groups (the all-polyethylene and the modular base plate) were not completely comparable. The all-polyethylene tibia group was older and had a lower BMI. They nicely document the operative time was quicker with an all-polyethylene tibial component, which of course corresponds with cost saving. The problem with that data point is operative time is subjective in the sense that it is surgeon dependent. 

There are certainly advantages and disadvantages of using an all-poly tibia vs. a metal backed tibia. This article reinforces other data that is available that suggests all-poly tibia is certainly less expensive, both early on and maybe in the long-term than modular base plates. Having said that, one does compromise the ability to do a late polyethylene exchange when using an all-poly tibia. To be truly cost-effective, which I believe the all-poly tibias are, one has to show that the durability in the long term is close to the modular trays. If in fact that failure rate is higher at 20 years (most data suggests that is not the case with well-designed all-poly tibias) then, of course, the cost-effectiveness decreases.

I am personally an advocate of the all-poly tibia. I use it in a majority of my total knee patients. This data adds to the existing literature that supports not only the cost-effectiveness of all-poly tibias, as well as comparable readmission and emergency room visits.

I do agree with the conclusion of the authors that all-poly tibia should be considered in appropriate selective patients to achieve optimal outcomes at a lower cost. This article supports that conclusion.

William M. Mihalko, MD, PhD

This is a timely retrospective study comparing 92 all-polyethylene tibias to 96 metal-backed total knee replacements in 188 patients and their 90-day reported quality metrics, along with differences in hospital and total costs. While the authors point to previous literature reporting that the mid- and long-term outcomes in older patients are equivalent, their study emphasizes the 6.2% decrease in hospital-based costs with all-polyethylene tibias. With increasing numbers of total knees being performed and an exponential rise in numbers expected over the next 10 years, it is important for arthroplasty surgeons to consider the cost basis of their treatment, including implant costs. The authors also found a significant decrease in operative time for the all-polyethylene tibia group (which can further decrease operating room costs), which they noted was unexpected, but attributed this to less time trialing and shorter time to closure once the all-polyethylene tibia was implanted. I appreciate the authors’ efforts in this time of the Comprehensive Care for Joint Replacement and bundled payments to highlight the possible cost savings with all-polyethylene tibia in older patients with a lower BMI and the possible realization of hospital cost savings, which may be considerable.