The AAOS American Joint Replacement Registry

The American Joint Replacement Registry (AJRR) is the world’s largest registry of hip and knee replacement data by annual procedural count. The Registry contains data on 3 million+ procedures from hospitals, ambulatory surgery centers (ASCs), and private practice groups in all 50 states and the District of Columbia.

By collecting and reporting data, the AJRR provides actionable, evidence-based information to guide physicians and patient decision-making to improve care. It empowers health care organizations to enhance the patient experience and benchmark performance, orthopaedic surgeons to reduce complications and revision rates, and device manufacturers to strengthen post-market surveillance.

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AJRR Participation Benefits

Participating in AJRR provides access to sitewide, systemwide, and nationwide data. Reuse of Registry data has value to certifying bodies, quality reporting, device surveillance, reimbursement, and quality measurement efforts.

A few top benefits of AJRR participation include:

Learn more about AJRR participation benefits here

Learn more about the quality initiatives that AJRR can help meet here.

Enrolling in the AJRR is Easy

Your site can join the AJRR in 5 simple steps. Learn about the enrollment process here. Visit the AAOS Registry Program FAQs page for more details about Registry Program participation. If you have additional questions about joining the AJRR, please email or call (847) 292-0530.

AJRR Data Elements Collected

The AJRR collects hip and knee arthroplasty procedures in three data types:

  • Procedural data is patient-related, hospital/practice-related, surgeon-related, and procedure-related data that includes information about comorbidities, length of stay, and operative complications.
  • Post-operative data includes 90-day readmission data and post-operative complications data.
  • PROMs data captures a patient’s self-assessment regarding their health status and may include questions related to physical function, mental attitude, mobility, social function, and bodily pain. AJRR recommends collecting a health-related quality of life measure and a hip or knee-specific measure.



  • Name (Last, First)
  • Date of Birth
  • Social Security Number
  • Diagnosis (ICD-9/10, CPT)
  • Gender
  • Race/Ethnicity
  • Height + Weight/Body Mass Index
  • Payer Status

Site of Service

  • Name and Address (TIN, NPI)


  • Name (NPI)
  • Trainee


  • Type (ICD-9/10, CPT)
  • Date of Surgery
  • Length of Stay
  • Surgical Approach
  • Surgical Technique
  • Laterality
  • Implants (Manufacturer, Lot #)
  • Anesthesia


Comorbidities and Complications

  • Comorbidities (ICD-9/10, CPT)
  • CJR Risk Variables
  • Height + Weight/Body Mass Index
  • Length of Stay
  • American Society of Anesthesiologists Score
  • Charlson Index
  • Operative and Post-operative Complications

Patient-reported Outcomes


  • PROMIS-10 Global or VR-12
  • HOOS, Jr.
  • KOOS, JR.

Also Accepted:

  • SF-36 v1
  • Oxford Hip and Knee Scores
  • Knee Society Knee Scoring System
  • Harris Hip Score
  • WOMAC (Modified via HOOS and KOOS)
  • SF-12, EQ-5D, WOMAC (only accepting final scores)
  • PROMIS-29
  • PROMIS Anxiety
  • PROMIS Depression
  • PROMIS Pain Interference
  • PROMIS-CAT (only accepting summary scores)

Interested in viewing the Data Specifications or Data Dictionary for AJRR? These documents are proprietary and can be accessed in the Tools & Resources tab on AAOS RegistryInsights®. For more information, please contact AAOS Registry Program staff at

AJRR Data Submission

After AJRR participating sites collect the necessary data elements, they submit their data through the AAOS RegistryInsights® data upload process via a secure file transfer protocol (SFTP) or hypertext transfer protocol secure (HTTPS).

Data submission best practices include:

  • Submitting data monthly
  • Consulting with your site’s IT team to set up automated reports
  • Monitoring data submission uploads and addressing errors
  • Utilizing an AAOS Registry Program Authorized Vendor to facilitate the data submission process

For more information about AJRR data submission, click here.

AJRR Supporters

View information about AJRR’s supporters here.

AJRR Leadership

The AJRR Steering Committee is comprised of stakeholders from various disciplines that are all vested in improving orthopaedic care. The AJRR Steering Committee members and the organizations they represent include:

  • James I. Huddleston, III, MD, FAAOS, Chair
    Stanford University
  • Scott M. Sporer, MD, FAAOS, Vice Chair
    Midwest Orthopaedics at Rush
    Central DuPage Hospital
  • James A. Browne, MD, FAAOS
    University of Virginia
  • Antonia F. Chen, MD, MBA, FAAOS
    Brigham and Women’s Hospital
  • Paul J. Duwelius, MD, FAAOS
    Orthopedic and Fracture Specialists
  • Brian R. Hallstrom, MD, FAOA, FAAOS
    University of Michigan
  • Richard L. Illgen, II, MD, FAAOS
    University of Wisconsin-School of Medicine and Public Health
  • William A. Jiranek, MD, FACS, FAAOS
    Duke University
  • Leslie Klemp, MS, RN, NE-BC, CPHQ
    Rush University Medical Center
  • William J. Long, MD, FRCS, FAAOS
    Hospital For Special Surgery
  • Howard J. Marans, MD
  • James D. Slover, MD, FAAOS
    Northwell Health
  • Bryan D. Springer, MD, FAAOS
    OrthoCarolina Hip and Knee Center
  • Jeffrey B. Stambough, MD, FAAOS
    University of Arkansas For Medical Sciences

Past AJRR Steering Committee Chairs:

  • 2023-Present
    James I. Huddleston, III, MD, FAAOS
  • 2020-2022
    Bryan D. Springer, MD, FAAOS
  • 2018-2019
    Kevin J. Bozic, MD, FAAOS, MBA
  • 2015-2017
    Daniel J. Berry, MD, FAAOS
  • 2013-2014
    William J. Maloney, MD, FAAOS
  • 2010-2012
    David G. Lewallen, MD, FAAOS