Abstract
The American Joint Replacement Registry continues to grow, as represented by the 4.3 million hip and knee arthroplasties analyzed in the 2024 American Joint Replacement Registry Annual report. Highlights of this report are found in the following article. We encourage readers to access the full report at https://www.aaos.org/registries/publications/ajrr-annual-report/.
Keywords: American Joint Replacement Registry, Highlights, Total hip arthroplasty, Total knee arthroplasty
American joint Replacement registry 2024 executive summary
The 2024 American Joint Replacement Registry (AJRR) Annual Report is the 11th iteration of the report, capturing 4.3 million hip and knee arthroplasties performed by nearly 5000 surgeons across 1447 member sites from all 50 states and the District of Columbia. The AJRR remains the largest orthopaedic and joint arthroplasty registry in the world by annual procedure volume; as a result, the 2024 Annual Report contains some of the most powerful analyses of recent practice trends, implant utilization, and implant survivorship currently available.
With recent mandates in the collection of patient-reported outcome measures (PROMs) via the Centers for Medicare and Medicaid Services (CMS) Hospital Inpatient Quality Reporting Patient-Reported Outcome Performance Measure (PRO-PM), there has been a significant focus on reporting PROMs data. By the end of 2023, 44% of AJRR member sites had submitted PROMs data, representative of a 27% increase relative to the 2023 Annual Report. To support member sites in reporting PROMs data to CMS, AJRR updated its PROMs data collection portal and file upload specifications; subsequently, AJRR successfully reported data from member sites to CMS during the second voluntary Inpatient Quality Reporting PRO-PM reporting window in September 2024.
As an increasing volume of primary total hip (THA) and total knee arthroplasty (TKA) procedures are performed in ambulatory surgery centers (ASCs), the AJRR has dedicated resources to increasing ASC participation and data capture. Subsequently, cases reported by ASCs to the AJRR increased by 70% over the past year and have increased by nearly 300% since the 2021 Annual Report [1,2]. Further increases in ASC procedure volume captured in AJRR over the next few years appear likely, as CMS PRO-PM mandatory reporting periods for outpatient hip and knee arthroplasty are scheduled to begin in the year 2028 [3].
An important focus of the American Academy of Orthopaedic Surgeons Registry Program remains the tracking and monitoring of outcomes for participating institutions and surgeons. To maximize the utilization of registry data for this purpose, RegistryInsights® has added a scorecard dashboard view available at both the site and individual surgeon level with key outcomes metrics displaying trends over time against national registry benchmarks.
Analyses of AJRR data for the purpose of specific clinical research projects are available via the American Academy of Orthopaedic Surgeons Registry Analytics Institute. Over the past year, AJRR data were utilized in 18 unique peer-reviewed manuscripts and over 35 abstract presentations. Research topics included periprosthetic joint infection [4,5], periprosthetic femur fracture following THA [6], uncemented TKA [7], and patellar resurfacing [8,9].
2024 AJRR Annual Report highlights
The 2024 AJRR Annual Report contains 3,715,320 validated primary and revision THA and TKA procedures performed during years 2012 to 2023. Primary TKA (51.1%) and primary THA (32.4%) comprised the majority of procedures captured. Regarding patient demographics, 58.6% of patients were female, 76.6% identified as non-Hispanic White (race was unreported in 14.0% of patients), and the mean age of primary TKA and THA patients was 67.6 years and 65.6 years, respectively. The average annual elective surgical volume of submitting arthroplasty surgeons was 44.3 primary THAs (increased from 39.2 in 2022) and 65.4 primary TKAs (increased from 56.0 in 2022) [10].
Trends identified in prior iterations of the AJRR annual report that continued in 2023
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Postoperative length of stay (LOS) continued to decline. For primary THA, mean LOS was 1.1 days in 2023, decreased from 1.2 days in 2022 and 3.0 days in 2012. For primary TKA, mean LOS was 1.1 days in 2022 and 2023, decreased from 2.9 days in 2012.
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Utilization of general anesthesia (GA) without a peripheral nerve block for elective primary THA and TKA decreased further; GA in isolation was used in 36.4% of elective primary THA in 2023 (48.8% in 2017) and 22.7% of primary TKA (40.6% in 2017). However, use of GA in tandem with a peripheral nerve block continues to increase, used in 3.7% of primary THA in 2023 (1.0% in 2017) and 13.0% of primary TKA in 2023 (3.5% in 2017).
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Use of ceramic femoral heads in elective primary THA increased in popularity, accounting for 81.9% of all implants in 2023. This represents an increase from 81.4% utilization in 2022 and 38.1% in 2012.
Trends identified in prior iterations of the AJRR Annual Report that changed in 2023
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Primary THA was increasingly utilized for the treatment of femoral neck fractures from 2012 to 2022; however, since 2022, the rate of primary THA utilization for the treatment of femoral neck fractures has remained stable at 27.7%.
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Use of dual-mobility (DM) constructs in elective primary THA increased from 2012 to 2020, reaching a peak utilization rate of 10.7% in 2020. Utilization of DM constructs subsequently decreased to 9.3% in 2021 and 7.5% in 2022. In 2023, utilization rates of DM constructs in elective primary THA remained steady at 7.5%.
Trends in primary THA
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Utilization rates of cemented femoral stem fixation in elective primary THA increased in 2023 to 5.1%; this comes after a decrease in the rate of cemented femoral stem fixation from 2021 to 2022. Overall, use of cemented femoral stem fixation in elective primary THA has increased from a utilization rate of 3.0% in 2012. The 2023 cemented femoral stem fixation rate of 5.1% represents the highest rate of cemented femoral component utilization in elective primary THA since the inception of the AJRR. Considering female Medicare patients aged 65 years and older that underwent an elective primary THA for primary osteoarthritis (OA), cemented femoral stems had a significantly lower cumulative rate of all-cause revision relative to uncemented femoral stems (adjusted hazard ratio [HR] 0.81, 95% confidence interval [95% CI] 0.72-0.90; P = .002).
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When a primary THA or hemiarthroplasty was performed for the treatment of a femoral neck fracture in 2023, cemented femoral stem fixation was used in 56.7% of cases (increased from 51.7% in 2022). Cemented femoral stem fixation was more common in hemiarthroplasties performed in elderly patients relative to hemiarthroplasties performed in younger patients, with utilization rates of 27.3% in patients aged <50 years, 28.5% in patients aged 50-59 years, 35.2% in patients aged 60-69 years, 42.2% in patients aged 70-79 years, 48.0% in patients aged 80-89 years, and 54.3% of patients aged ≥90 years.
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Large femoral heads (≥36 mm in diameter) were more popular than ever, with 36-mm heads implanted in 63.8% of elective primary THA in 2023 (increased from 62.3% in 2022 and 48.0% in 2012). Femoral heads ≥40 mm were used in 9.9% of elective primary THA in 2023, increased from 8.8% in 2022 and 8.1% in 2012.
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Ceramic on highly cross-linked polyethylene remains the most common bearing surface in elective primary THA, accounting for 73.5% of cases in 2023. Conversely, utilization rates of metal heads on highly cross-linked polyethylene reached an all-time low of 3.7% in 2023 (decreased from 48.8% in 2012). Ceramic on polyethylene articulations had a significantly lower rate of cumulative all-cause revision relative to metal on polyethylene articulations in Medicare patients aged 65 years and older (adjusted HR 1.14, 95% CI 1.08, 1.19; P < .001).
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Robotics were used in 6.6% of elective primary THA in 2023, stable from 6.6% in 2022 and increased from 2.0% in 2017. Use of navigation in elective primary THA decreased from 5.1% in 2022 to 2.8% in 2023.
Trends in revision THA
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The most common reason for revision THA in 2023 was infection (26.3%) followed by instability (20.6%). This continues the overall trend of infection as the most common diagnosis associated with THA revision from 2012 to 2023 (21.4%).
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DM bearings were used in 34.0% of revision THA for instability in 2023, while constrained liners were used in 34.3% of such cases. The use of constrained liners for revision THA for instability has been steadily increasing since a low of 23.2% in 2020, while DM usage has remained stable and standard bearings have steadily decreased (43.4% in 2020, to 31.7% in 2023).
Trends in primary TKA
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For the first time, more granular TKA constraint and insert design categories were analyzed in the 2024 AJRR Annual Report. Medial congruent primary TKA designs have seen a rapid increase in popularity, accounting for 32.1% of cases in 2023 (24.1% in 2022 and 2.3% in 2017). While posterior stabilized designs decreased in popularity in 2023 (40.8% of cases, down from 44.5% of cases in 2022), they remain the most used primary TKA implant design. Cruciate retaining designs were used in 9.0% of cases in 2023, down from 35.6% in 2012.
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Utilization of highly cross-linked polyethylene and antioxidant polyethylene inserts increased from 2022 to 2023. Highly cross-linked polyethylene remains the most used insert material accounting for 45.9% of primary TKA. Conventional polyethylene was used in 14.6% of primary TKA in 2023, a decrease from 17.1% in 2022 and 42.5% in 2012. Notably, there were no significant differences in rates of cumulative all-cause revision between highly cross-linked polyethylene, antioxidant polyethylene, or conventional polyethylene inserts in primary TKAs performed for primary OA in Medicare patients aged 65 years and older (P > .05 for all).
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Patellar resurfacing remains commonplace in primary TKA, performed in 87.0% of cases in 2023. However, rates of patellar resurfacing have decreased over time (87.0% of cases in 2023, decreased from 88.8% in 2022 and 95.9% in 2012).
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Cementless fixation in primary TKA continues to rise in popularity, accounting for 21.8% of primary TKA in 2023. Considering primary TKA in male Medicare patients aged 65 years and older, there was no statistically significant difference in the rate of cumulative all-cause revision between cementless and cemented fixation (adjusted HR 1.035, 95% CI 0.94-1.14; P = .05). When considering male patients less than age 65 undergoing primary TKA for primary OA, there remained no statistically significant difference in the rate of cumulative all-cause revision between cementless and cemented TKA (adjusted HR 0.93, 95% CI 0.85-1.02; P = .103); however, hybrid fixation had a significantly lower rate of cumulative all-cause revision relative to cemented fixation (adjusted HR 0.84, 95% CI 0.72-0.99; P = .04). Cementless fixation had an increased rate of cumulative all-cause revision relative to cemented fixation in primary TKA in female Medicare patients aged 65 years and older (adjusted HR 1.17, 95% CI 1.05-1.29; P = .003).
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Robotics were used in 15.9% of primary TKA in 2023, increased from 12.5% in 2022, and an 8-fold increase from 2017 (1.8%). Similar to primary THA, use of computer navigation declined from 5.2% in 2022 to 4.0% in 2023.
Trends in revision TKA
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The most common reason for revision TKA in 2023 was infection (32.5%). This continues the overall trend of infection as the most common diagnosis associated with THA revision from 2012 to 2023 (33.1%), followed by mechanical loosening (24.4%).
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Infection was also the most common diagnosis associated with TKA re-revisions from 2012 to 2023 (37.3%).
As the AJRR Annual Report enters into its second decade of existence, it remains the pre-eminent source of data and analyses on hip and knee arthroplasty practice trends and rates of implant utilization and survivorship in the United States. Increasing rates of participation through the addition of new member sites and improving rates of data capture and submission from existing sites will further improve the quality, completeness, and power of the data contained with the AJRR. To learn more about specific AJRR initiatives and to review the full 2024 AJRR Annual Report, visit https://connect.registryapps.net/2024-ajrr-annual-report.
Conflicts of interest
Vishal Hegde receives speakers' bureau/paid presentations for Ortho Development; is a Paid consultant for Globus Medical; receives research support from Ortho Development and Zimmer Biomet; receives fellowship support from Smith & Nephew; and is a board member/committee appointments for AAHKS Research Committee. AAOS AJRR Research Projects Subcommittee, and AAOS Adult Reconstruction Knee Program Committee. Brett Levine is a paid consultant for Link, Enovis, and Zimmer Biomet; receives royalties, financial or material support from Human Kinetics, Slack INC., Wolters Kluwer, and Elsevier; is a member of the Medical/Orthopaedic publications editorial/governing board at Orthopedics, JOA, AT (Editor-in-chief); and is a board member/committee appointments for AAOS EQBV Committee, AAHKS Member at Large, and HS/KS Digital Media Committee. Anna Cohen-Rosenblum is a paid consultant for Zimmer Biomet; receives royalties, financial or material support from Elsevier and JBJS; is a memver of the Medical/Orthopaedic publications editorial/governing board at Arthroplasty Today, Journal of Arthroplasty; is a board member/committee appointments for AAOS, AAHKS, SICOT, and RJOS. The other authors declare there are no conflicts of interest.
For full disclosure statements refer to https://doi.org/10.1016/j.artd.2025.101727.
Supplementary data
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