Abstract
Introduction
Patellar resurfacing is performed in more than 90% of primary total knee arthroplasties (TKAs) in the United States, yet far fewer patellae are resurfaced internationally. Multiple randomized controlled trials have shown decreased revision rates in patients with resurfaced patellas (RP) vs. non-resurfaced (NR). However, most of these studies showed no difference in patient satisfaction, anterior knee pain, or knee society scores. (Figure 1) Given uncertain benefits, the purpose of this study was to determine if the rates of patellar resurfacing have changed over the past 10 years worldwide.
Methods
Data was obtained via direct correspondence with registry administrators or abstracted from the annual reports of six national joint registries: Australia, Denmark, England, New Zealand, Norway, and Sweden. Rates of patellar resurfacing between 2003 and 2013 were collected. Where data was available, subgroup analysis was performed to examine revision rates among RP and NR TKAs.
Results
The average rates of patellar resurfacing from 2003 to 2013 ranged from 5% (Norway) to 71% (Denmark). Three countries showed a decreased rate of patellar resurfacing over this time period while two demonstrated an increase. The largest decrease in resurfacing rates was in Sweden (15% to 2%), while the biggest increase was in Australia (44% to 53%). (Figure 2) In 2010, 48,367 of 137,813 (35%) primary TKAs from all six countries were resurfaced. (Figure 3) Among RP and NR TKAs, Australia documented a 10-year cumulative revision rate (CRR) of 4.9% and 6.0%, respectively. Sweden showed a 10-year CRR of 4% in both groups.
Conclusion
While not all national joint registries report rates of patellar resurfacing, it is clear that most countries outside of the US continue to resurface a much smaller proportion of patellas in primary TKA. Worldwide, the rates of patellar resurfacing have changed little in the past decade.
