2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Factors Influencing the Decision to Undergo ACL Reconstruction after Unsuccessful Non-Surgical Management: A Sub-Analysis of the ACL SNNAP Study

Aurnia Barlow, BA, Oxford UNITED KINGDOM
Elizabeth Conroy, PhD, MSc, BSc, Oxford UNITED KINGDOM
Loretta Davies, DPhil, MSc, Oxford, Oxfordshire UNITED KINGDOM
Vidoushee Jogarah, MMath, Oxford UNITED KINGDOM
Andrew James Price, DPhil, FRCS(Orth), Oxford, Oxfordshire UNITED KINGDOM
David J. Beard, MA, MSc, DPhil, FBOA(Hon) FRCS(Hon), Prof., Oxford, Oxfordshire UNITED KINGDOM
Acl Snnap Study Group, Collective, Oxford, Oxfordshire UNITED KINGDOM

Oxford University, Oxford, UNITED KINGDOM

FDA Status Not Applicable

Summary

Factors influencing the decision to undergo ACL reconstruction after unsuccessful non-surgical management - a sub-analysis of the ACL SNNAP study.

Abstract

Background

Management of anterior cruciate ligament injuries (ACL) with initial rehabilitation and optional delayed anterior cruciate ligament reconstruction (ACLR) is common in clinical practice. However, it remains uncertain what factors influence the need/decision to undergo ACLR. Identification of such factors could help predict the need for ACL reconstruction and support earlier decision making on whether surgery is needed or not (from the outset of injury).

Objective(s): To identify any objective factors in patients with non-acute ACL injury that predicted or were associated with a decision to undergo ACL reconstruction after initial treatment with rehabilitation in the ACL SNNAP trial.

Method/Design: In the recently published multi-centre NIHR funded ACL SNNAP randomised controlled trial, 316 patients with a non-acute ACL rupture were randomised to ACL reconstruction or non-surgical management (rehabilitation plus optional delayed ACL reconstruction). We conducted an exploratory analysis of the subset of 159 participants who were randomised to non-surgical management. Variables collected from patients prior to treatment in the trial, which included sex, age (years), time since injury (months), baseline KOOS4 score, and pre-injury Tegner activity score, were explored using univariate logistic regression. Statistically significant variables were used in multivariate analysis to identify factors that may have led individuals to a decision to undergo subsequent ACL reconstruction.

Results

Of those randomised to rehabilitation in the ACL SNNAP trial (N=159), 41% (n = 65) underwent subsequent reconstruction within 18 months with 38% (n = 61) completing rehabilitation and not undergoing surgery. Neither sex, age or time since injury were factors in the decision to undergo subsequent reconstruction (no differences between groups). There was a significant difference between groups in both baseline functional status (KOOS4) (OR: 0.979, p=0.0285) and pre-injury activity level (Tegner activity score) (OR: 1.201, p=0.0248). A lower Baseline KOOS4 score and a higher pre-injury Tegner Activity score was related to subsequent reconstruction.

Summary and Conclusions: In this study, higher preinjury activity levels (assessed by the Tegner score) and lower baseline functional status (measured by the KOOS4 score) were found to influence the decision to undergo reconstruction. These factors should be considered in the management of patients with non-acute anterior cruciate ligament injuries. Further research is needed to explore other potential predictors and subjective factors such as patients' and clinicians’ perspectives in the decision to undergo ACLR to help inform practice.

Trial registration: Current Controlled Trials ISRCTN10110685; ClinicalTrials. gov Identifier: NCT02980367.

Funding: This (ACL SNNAP) award was funded by the National Institute of Health and Care Research (NIHR), Health Technology Assessment programme (NIHR award ref: 14/140/63).