ACL Registry: Predicting Follow-Up Compliance and Why It Matters
"Discover the surprising factors influencing patient participation in ACL registries and how this impacts research and treatment outcomes."
Anterior cruciate ligament (ACL) injuries are among the most common orthopedic issues, frequently requiring ACL reconstruction (ACLR). Given their high incidence and significant impact on patients, ACL injuries and their management remain a focal point in orthopedic research. However, while many studies concentrate on surgical techniques and outcomes, few address the methods of research themselves, particularly how to minimize variability and enhance validity in reported results.
Pathology-driven registries play a crucial role in monitoring clinical practice and providing valuable data for medical research. These registries, however, are susceptible to various forms of bias, including patient noncompliance in completing registry forms. This issue is particularly relevant in registries heavily reliant on patient-reported outcomes (PROs). Addressing and predicting noncompliance is essential to improving the efficacy and value of registry-based data.
A recent study aimed to pinpoint patient-specific factors influencing compliance with ACLR registry forms at 6, 12, and 24 months postoperatively. The researchers hypothesized that no specific patient factors would correlate with compliance at any of the investigated time points, setting the stage for potentially surprising revelations.
The Rise of ACL Registries
ACL registries have become important tools for understanding ACL injuries and their treatment. Registry data has helped identify factors associated with increased injury risk and evaluate how treatment choices affect patient-reported outcomes. One integrated healthcare system's ACL reconstruction registry includes more than 35,000 patients, while the Luxembourg hospital-based registry began in March 2011 and had recorded more than 300 ACL reconstructions by the end of 2014.
What Factors Influence ACL Registry Compliance?
Researchers at a major medical center retrospectively reviewed data from patients prospectively enrolled in the ACLR registry since March 2015. The study included patients followed for at least six months, excluding those who didn't complete initial registry forms. Participants filled out forms preoperatively and at 6, 12, and 24 months postoperatively. The study looked at several factors:
- Age
- Race
- Employment Status
- Medical Insurance
- Smoking Status
- Driving Distance to the Hospital
- Importance of Returning to the Same Level of Sporting Activity
Current Evidence on Follow-Up
A systematic review in orthopaedics reported that inadequate education about treatment options and clinic location contributed to patients failing to return for follow-up, particularly in more rural populations. In a knee-surgery study, black race and lower IPAQ activity level independently predicted lower completion of surveys at two years, although the model's area under the curve was 0.62. A July 2023 systematic search also examined how patient-reported outcome measures are collected through registries involving people younger than 18 years with orthopaedic diagnoses.
What Registry Comparisons Can Show
The cited report on incisional-hernia repair illustrates how registry-style outcome tracking can capture postoperative complications. It reported seroma formation in six patients, deep vein thrombosis in one patient, and a non-fatal pulmonary embolism in another. These findings show the value of recording distinct complication types rather than treating postoperative morbidity as a single outcome.
The Road Ahead: Improving Registry Compliance
By understanding the factors that contribute to non-compliance, future studies can be designed to better engage at-risk patients, ensuring more complete and reliable data. This, in turn, leads to more robust research and improved patient outcomes in ACL reconstruction and related orthopedic procedures.
Predicting Registry Compliance
A study of patients prospectively enrolled in an ACL reconstruction registry examined patient factors associated with completing ACLR registry forms. The retrospective review included patients followed for at least six months and focused on compliance at postoperative registry assessments. The study's stated purpose was to determine which patient factors influence completion, while the available source material does not establish a single definitive predictor.
From Data to System Improvement
A scoping review reported that ACL registry data has deepened understanding of factors associated with an increased risk of sustaining an ACL injury. It also described the use of registry data to evaluate treatment factors and their effects on patient-related outcomes. This broader role makes registry completeness a systemic research concern, because missing follow-up information can limit the assessment of treatment results.
Why Patient Participation Matters
The Norwegian knee ligament registry, established in 2004 and described as the first of its kind, used information from primary and revision ACL and PCL reconstructions to identify predictors of clinical outcomes and graft failure after ACL reconstruction. A pragmatic registry-based randomized controlled trial listed on ClinicalTrials.gov aims to investigate ACL injury treatment, fill knowledge gaps, facilitate shared decision-making, and strengthen patient treatment. These examples connect registry participation with both clinical evidence generation and decisions about patient care.