2023 ISAKOS Biennial Congress Paper
Mid-Term Follow-up of the STABILITY Study Multicenter RCT Comparing Anterior Cruciate Ligament Reconstruction With and Without Lateral Extra-Articular Tenodesis in Individuals at High Risk of Graft Failure
Katelyn Inch, MSc, London, ON CANADA
Dianne M. Bryant, PhD, London, ON CANADA
Robert Litchfield, MD, FRCSC, London, ON CANADA
Kevin R. Willits, MD, FRCS, London, ON CANADA
Andrew Firth, PhD, London, ON CANADA
Hana Marmura, BSc, London, ON CANADA
Richard Magony, MSc, London, ON CANADA
Stability Study Group, London, ON CANADA
Alan Getgood, MD, FRCS(Tr&Orth), DipSEM, London, ON CANADA
Fowler Kennedy Sport Medicine Clinic, London, Ontario, CANADA
FDA Status Not Applicable
Summary
Preliminary results of the STABILITY long-term follow-up suggest differences in graft failure rates persist longer than two years postoperative in favour of the added LET, with no negative influence on patient-reported outcome measures, or range of motion.
Abstract
Background
Studies have shown high ACL re-tear rates in patients returning to pivoting sports after ACL reconstruction (ACLR). The STABILITY study was a prospective, multicenter randomized clinical trial (RCT) comparing hamstring tendon (HT) autograft ACLR with or without a lateral extra-articular tenodesis (LET) that showed a significant reduction in graft failure rates with the addition of LET at two years postoperatively.
Objective
The purpose of this study was to conduct a mid-term follow-up (three, five and seven years postoperative) of patients involved in the STABILITY study at the Fowler Kennedy Sport Medicine Clinic (FKSMC) in London, Ontario, to determine if differences between the surgical groups persisted beyond two years.
Methods
Of the 196 participants at the FKSMC, 82 (42%) participated in this mid-term follow-up. Patients completed patient-reported outcome measures (PROMs) including the ACL Quality of Life Questionnaire (ACL-QOL), Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee Subjective Knee Form (IKDC), and Marx Activity Rating Scale (MARS). Adverse events and range of motion (ROM) measurements were recorded, and objective knee function was assessed by a surgeon. The primary composite outcome of clinical failure (asymmetric pivot shift and/or graft failure) was determined by the pivot shift test, presented as a relative risk reduction (RRR) and risk difference (RD). An analysis of covariance (ANCOVA) was conducted for PROMs and ROM, with days from surgery to follow-up and baseline values serving as covariates. We reported descriptive information and proportions of adverse events.
Results
There was no significant difference in the incidence of clinical failure between the ACLR only and ACLR + LET groups (RRR 0.25, 95% CI: -0.10 to 0.49, p=0.14 and RD 16%, 95% CI: -7% to 40%). There was a significant difference in incidence of graft failure favouring the ACLR + LET group (RRR 0.88, 95% CI: 0.08 to 0.98, p=0.04 and RD 18%, 95% CI: 3% to 34%). There was no statistically significant difference between groups for scores on the ACL-QOL (Adjusted Mean Difference (AMD) = 2.2, 95% CI: -5.9 to 10.3, p = 0.34), KOOS (AMD = 3.2, 95% CI: -1.6 to 7.9, p = 0.08), IKDC (AMD = 3.2, 95% CI: -2.4 to 8.7, p = 0.09), or MARS (AMD = -1.0, 95% CI: -3.1 to 1.2, p = 0.37). There were no significant differences between groups in side-to-side limb differences in extension and flexion. At least one adverse event (infection, stiffness, meniscal injury, graft failure, etc.) from the time of surgery to most recent follow-up was experienced by 47 of 82 (57%) patients.
Conclusion
While there was no statistically significant difference between groups in terms of ACLR clinical failure, the ACLR alone group experienced significantly more graft failures than the ACLR + LET group. Preliminary results of the STABILITY long-term follow-up suggest differences in graft failure rates persist longer than two years postoperative in favour of the added LET, with no negative influence on PROMs or ROM.