15 Years of Scandinavian Knee Ligament Registries: Lessons, Limitations and the Future of Real-World Evidence

One of the Most Established Orthopaedic Registry Networks

The Scandinavian knee ligament registries established across Sweden, Norway and Denmark between 2004 and 2005 represent one of the most mature real-world evidence infrastructures in musculoskeletal research.

By 2019, the registries had enrolled more than 70,000 patients and contributed to over 70 published studies.

An important structural feature of the Scandinavian systems is the use of unique personal identity numbers, enabling cross-registry linkage and long-term follow-up analyses.

Key Findings from 15 Years of Registry Data

Over time, the registries have generated insights across patient factors, treatment factors and injury-related variables.

Patient Factors

Registry analyses identified that younger patients demonstrated superior knee function outcomes but also a higher risk of revision surgery. Female patients showed an increased risk of contralateral ACL reconstruction rather than revision surgery.

Treatment Factors

The registries also highlighted the relationship between graft diameter and revision risk.

According to the published findings, every 0.5 mm increase in hamstring graft diameter was associated with a 14% reduction in ACL revision risk.

The data further demonstrated strong regional preferences in graft selection, with hamstring autografts dominating in Sweden (>90%) and Denmark (>80%).

Injury Factors

Concomitant cartilage injuries were associated with reduced revision risk but inferior patient-reported knee function outcomes.

The Emerging Role of Registry-Based Randomised Controlled Trials

One of the most significant future developments discussed in the publication is the use of registry infrastructures to support registry-based randomised controlled trials (R-RCTs).

The article references the TASTE trial in cardiology as an example of this model, highlighting:

- low per-patient trial costs,
- integration within routine clinical care,
- minimal loss to follow-up,
- and generation of real-world effectiveness data.

The Scandinavian knee ligament registries were identified as having the infrastructure necessary to support similar approaches within orthopaedics.

Priorities Identified for Future Registry Development

The publication further outlined three key priorities for the future evolution of the registries.

Inclusion of Non-Operative Patients

The authors highlighted that up to 50% of ACL injuries may be treated non-operatively, yet these patients remain underrepresented within current registry structures.

Enabling Registry-Based RCTs

A second priority was the development of registry-based randomised controlled trials to support low-cost and high-quality effectiveness research using existing clinical infrastructures.

International Collaboration and Standardisation

The publication also emphasised the importance of international collaboration and standardised data elements to enable multi-registry analyses and broader subgroup evaluations.

Conclusion

The Scandinavian knee ligament registries demonstrate how long-term registry infrastructures can generate clinically relevant real-world evidence across large patient populations.

At the same time, the publication illustrates how registries are evolving beyond observational data collection toward more integrated evidence-generation models, including registry-based randomised controlled trials.

If you would like to discuss registry strategy, real-world evidence generation or HTA considerations for medical technologies, please feel free to contact the team at athagoras Medtech directly.