Anterior Cruciate Ligament Reconstruction International Registries

This information on ACL registries has been written in conjunction with Heather A. Prentice from the Surgical Outcomes and Analysis, Kaiser Permanente, San Diego, California, USA

What are ACL Registries?

ACL registries collect outcome data on large numbers of patients undergoing ACL reconstruction surgery. Registries provide a mechanism for prospective surveillance of a well-defined patient population, providing long-term follow-up of patients, continuous feedback to surgeons and healthcare centers for patient safety and quality improvement, and allowing for identification of early failures and best clinical practices.

Registries can identify trends in clinical practice over time on a national or regional level. Patient, surgical, graft, and fixation characteristics on risk affecting short-term clinical outcomes following ACLR (i.e. infection and venous thromboembolism), as well as affecting long-term outcomes representing failure (i.e. reoperation and revision) are evaluated.

Current registries

Currently, there are established national ACL registries in Denmark, Luxembourg, Norway, Sweden, New Zealand, and the United Kingdom (UK), and a regional-based registry in the United States (US). There have been many analytical and collaborative studies.

The Danish Registry - Lead contact: Professor Martin Lind

The Denmark registry is a prospective, nationwide, and web-based clinical database initiated in 2005, and including over 23,000 total patients by the end of 2014 with 93% participation. The registry contains data on epidemiology and surgical techniques for primary and revision ACL and posterior cruciate ligament (PCL) procedures, including concomitant collateral ligament procedures performed in Denmark. Both public and private hospitals supply data to the Danish registry, submission in this official clinical database is mandatory. Preoperative (patient characteristics, demographics, and activity injury), intraoperative (concomitant injuries, graft type, and device choice), and 1-year surgical outcome data are recorded by surgeons. Patients report on subjective knee function using the self-assessment Knee Injury and Osteoarthritis Outcome score (KOOS) and Tegner functional score.

Norwegian registry - Lead contact: Lars Engebretsen

The Norwegian registry was the first national cruciate ligament registry, started in June 2004 and includes primary and revision ACL and PCL reconstructions, with a total number of patients approaching 20,000 as of by the end of 2014. Although initially voluntary, reporting to the registry is now mandatory of all public and private hospitals, with a report rate of 86% in 2008-2009. The Norwegian registry collects patient-specific data, surgical details, and intra-operative findings through a paper form filled out by the surgeon. Surgical outcomes are surgeon-reported and linked to the primary by the registry. Subjective outcome data is filled out by the patient preoperatively and 2, 5, and 10 years postoperatively. Currently, a secure web-based data entry system is being tested, allowing for inclusion of patients with ACL/PCL injuries treated non-operatively.

Swedish Registry - Lead contacts: Magnus Forssblad, Jon Karlsson and Kristian Samuelsson

The Swedish registry was initiated in January 2005 by Swedish ACL surgeons to allow all surgeons to access the registry database and results online. Protocol for the Swedish registry is nearly identical to Denmark and Norway; voluntary reporting to the registry by both public and private surgeons is over 90%. The registry included data on over 30,000 patients by the end of 2014. Surgeons report on patient characteristics, intraoperative findings, and graft and implant selection via standardized web-based forms; demographic information is then linked using Swedish social security numbers. Revisions are surgeon-reported and linked to the primary by the registry. Subjective patient outcome data is completed by the patient preoperatively and 1, 2, and 5 years postoperatively using the Swedish registry website or through scanned forms.

UK National Ligament Registry - Lead contact: Mr Tim Spalding

The UK registry was established in March 2013 and was modeled on the Scandinavian registries. Entry of patients is voluntary for surgeons, involving a fully on-line web-based data collection system. Data is collected on includes public and private funded patients and at the end of 2017 over 9000 patients had been entered into the registry. In the UK registry, patients and surgeons enter data via an on-line portal; at present the system covers primary ACLR only. Patients enter demographic, injury, KOOS, Tegner, IKDC subjective scores and the EQ5D assessment, which are collected at 1, 2, and 5 years postoperatively. Surgeons enter operative detail and any postoperative adverse events. Revision of cases depends on surgeons declaring further procedures.

Kaiser Permanente Registry - Lead contacts: Greg Maletis and William Burfeind

The US-based registry includes a large, integrated health care system serving over 9.5 million members in eight geographical regions of the US. The registry was established in February 2005 and registered over 30,000 cases by the end of 2014, in 2011 voluntary participation to the registry was 93%. The US-based registry collects operative data, including intraoperative findings, graft type, and fixation devices, at the point of care using paper forms completed by the surgeon. This data is then supplemented with additional data elements collected using the electronic health record (EHR), administrative claims data, membership data, and mortality records. Outcomes are prospectively monitored and validated by trained clinical content experts using the institution’s EHR.

Luxembourg Registry - Lead contact: Professor Romain Seil

The Luxembourg registry is a hospital-based registry, started in March 2011 and registered over 300 ACLR by the end of 2014. This registry includes all patients with an ACL injury documented clinically and with MRI regardless of receiving operative or non-operative treatment. The Luxembourg registry prospectively collects demographic, patient characteristic, and injury information using questionnaires completed by the patient and operative data using paper forms filled in by surgeons. One-year postoperative outcomes, including revision and reoperation, depends on the patient reporting back to a participating hospital for either ACL or other knee pathologies. All data are saved using software specific to the follow-up of patients with an ACL injury and checked daily with the help of a scientific coordinator.

New Zealand Ligament registry - Lead contact: Mark Clatworthy

The ACL registry in New Zealand was established in 2013 by the knee and sports society, initially by a pilot study and then implementation of a full ACL registry. This was initially rolled out using 5 surgeons over a 3-month period. The pilot was a successful means for capturing pre-operative and operative data. The results of this pilot study were presented at the NZOA meeting in 2014. The ACL registry has now been adopted as the nationwide standard of reporting for ACL surgery. Nationwide patient registration began roll-out in November 2014.

What has analysis of the registries shown?

Data has been collected prospectively and by virtue of attempting wide involvement of surgeons and patient’s data collection is focused on core measures that have been agreed across the registries. Primary ACLR patients in all registries are mostly male and under 30 years of age. Almost 20% of knees in Norway have had a prior operation, while less than 5% appear to have been previously operated on in the US. Over three quarters of patients in the Scandinavian countries, Luxembourg, and the US report a normal contralateral knee. While Luxembourg and the US tended to have a short duration from injury to reconstruction, most reconstructions for Denmark, Norway, Sweden and UK occurred at least 12 months following the injury.

Analysis shows that Soccer appears to be the most commonly reported mechanism of injury. Winter sports and handball are common associated sports in Denmark and Norway; winter sports, handball, and basketball in Luxembourg; winter sports and floor ball in Sweden; and basketball and American football in the US. Analysis of grafts used shows that autograft is the primary choice, but use of allograft in the US is high compared to all other countries. Allograft and method of fixation vary by country.

Future intentions of Registries

National and regional ACL registries offer a real world clinical perspective with the goal of improving quality and patient safety through research focused on understanding factors associated with positive and negative surgical outcomes. Registries aim to improve both data collection with focused core required data items and to provide information for individual surgeons and the wider surgeon community to reflect on practice in order to improve outcomes. Registries will continue to share information and knowledge.

Further information