Early Results From the American Joint Replacement Registry: A Comparison With Other National Registries

The American Joint Replacement Registry (AJRR) was created to capture knee and hip arthroplasty data in the United States. The purpose of this study was to compare early reports from the AJRR to other national registries to identify topics for future analysis.

Hip and knee arthroplasty data were extracted from the AJRR, Australia, New Zealand, United Kingdom, Norway, and Sweden from 2014 to 2016. Hip arthroplasty data including femoral and acetabular fixation, bearing surface, head size, dual-mobility bearings, resurfacing, and revision burden were compared. Knee arthroplasty data including polyethylene type, unicondylar arthroplasty, mobile bearings, cruciate-retaining implants, patella resurfacing, and revision burden were compared. Registry characteristics and patient demographics were reported using descriptive statistics.

In 2016, the AJRR captured 28% of arthroplasty procedures performed in the United States compared with 95%-98.3% among other registries. Cementless femoral fixation was 96.7% in the AJRR compared with 21.8%-63.4%. Ceramic and 36-mm heads were most common in AJRR; all other registries reported that metal and 32-mm heads were most popular. Dual-mobility articulations were used in 8% of primary and 28% of revision total hip arthroplasty procedures in the AJRR. The AJRR reported a unicondylar knee arthroplasty rate of 3.2% compared with 5.1%-13.3% in other registries, but the highest rates of posterior-stabilized total knee arthroplasties (48.5% compared to 8.2%-28.7%) and patella resurfacing (93.9% compared to 2.4%-51.6%).

Several differences in hip and knee arthroplasty practices exist between the United States and other countries. Future studies should focus on understanding why differences in practice trends exist and assess outcomes associated with these practices.

Level III, retrospective.