ACL graft failure in high-risk patients: What the STABILITY study shows about adding LET

Key takeaways¹

• In high-risk anterior cruciate ligament (ACL) patients aged 14–25 years, adding Lateral Extra-Articular Tenodesis (LET) was associated with a significant lower risk of graft clinical failure* (p<0.0001)
• Graft rupture was higher with ACL reconstruction alone: 11% compared to 4% with ACL reconstruction plus LET at two years
• No long-term differences in pain, function, or return-to-sport
• Evidence supports the selective use of LET in high-risk cases, rather than routine addition

Results at a glance¹

Why graft failure remains a concern

Most patients do well after ACL reconstruction, but graft failure and persistent instability remain concerns in younger, high-risk individuals returning to pivoting or contact sports. Recognised risk factors include a high-grade pivot shift, generalised ligamentous laxity, and early return to high-risk sport.¹

Studies in young athletes have reported graft failure rates approaching 20%, with an additional risk of contralateral ACL injury in the years following reconstruction. These reinjury rates highlight the importance of strategies that improve rotational stability and protect the graft during the early healing phase.²

While intra-articular ACL reconstruction reliably restores anterior stability, it does not always fully control rotational instability. This has driven interest in adjunctive extra-articular procedures such as lateral extra-articular tenodesis (LET), particularly in patients at higher risk of reinjury.¹

What does the evidence show?¹

In the STABILITY randomised controlled trial, patients who underwent ACL reconstruction with the addition of LET experienced significantly fewer clinical failures than those treated with ACL reconstruction alone. Failure was defined using a composite outcome that included either graft rupture or persistent rotatory laxity.

At two years, graft rupture rates were reduced from 11% in the ACL only group to 4% in the ACL + LET group, corresponding to a clinically meaningful reduction in failure risk. The number needed to treat suggested that adding LET prevented one graft rupture for approximately every 14 patients treated.¹

The STABILITY study: How the study was performed: evidence in a high-risk population¹

Earlier ACL reconstruction studies often focused on patient-reported outcomes when comparing surgical techniques. While important, these measures may not always detect meaningful differences in surgical strategies in young, highly active populations, where ceiling effects are common and the primary clinical concern is reinjury.

The STABILITY randomised controlled trial was designed to address this gap by focusing on a clinically meaningful outcome; graft failure and persistent rotatory laxity, in a population known to be at higher risk of reinjury.

A total of 618 patients aged 14-25 years were enrolled and considered at increased risk of reinjury based on at least two criteria, including a high-grade pivot shift, participation in competitive pivoting sports, and generalised ligamentous laxity.

Patients were randomised to undergo standard hamstring autograft ACL reconstruction with LET (n = 306) or without LET (n = 312), with outcomes assessed through two years.

The trial was conducted across multiple Canadian and European centres, and the study population reflects patients commonly encountered in routine sports medicine practice.

Pain, function and return-to-sport

A common concern with adding LET is whether it negatively affects recovery or longer-term outcomes. In the STABILITY trial, patients who had LET reported slightly higher pain scores in the first three months, reflecting the additional lateral procedure. These differences did not reach clinically important thresholds and resolved beyond early recovery.

By one year, and continuing through two years, pain, function, activity level and quality of life were comparable between groups. Return-to-sport was delayed by approximately one month in the LET group, but overall exposure to sport was similar, suggesting that the reduction in graft rupture was not simply due to delayed activity.¹

A sub-analysis from the STABILITY cohort also suggests that rehabilitation timing may influence reinjury risk. Each additional month exposure to sport was associated with increased odds of rupture by 18%, reinforcing the importance of structured rehabilitation and cautious return-to-sport decision making.³

Why might LET make a difference?

One explanation is that LET may help protect the ACL graft during early healing. Biomechanical studies suggest that adding LET can reduce strain on the intra-articular graft, potentially offloading it during ligamentisation; a phase when the graft may be particularly vulnerable.²

This supports the concept that anterolateral rotatory laxity reflects combined injury to both the ACL and the anterolateral complex, and that addressing both structures may be necessary in selected patients.²

Which patients may benefit most?

Multi-variable analyses from the STABILITY cohort identified several predictors associated with higher graft failure risk, including younger age, high-grade pivot shift, generalised ligamentous laxity and increased posterior tibial slope. These factors are typically assessed during pre-operative evaluation and may help guide decisions about when lateral reinforcement strategies should be considered^3,4

Findings from the STABILITY cohort informed the International Consensus on ‘Lateral Extraarticular Procedures with ACL Reconstruction’; recommending that procedures such as LET work best as a targeted strategy rather than a routine addition.^4-6

Together, these factors define a subgroup in which additional lateral reinforcement may meaningfully reduce the risk of failure.⁴

 

Addressing safety concerns

In the STABILITY trial, serious LET-related adverse events were uncommon. More patients experienced lateral hardware irritation in the LET group (14 v 4) requiring removal in 10 patients, but no meaningful differences in range of motion were observed at one or two years, and overall safety profiles were comparable between groups.^1,3

 

 

Translating evidence like the STABILITY trial into practice requires reliable fixation and reproducible technique execution. Smith+Nephew’s ACL and lateral fixation portfolio is designed to support surgeons implementing LET-augmented ACL reconstruction in patients, with a focus on consistent workflows and controlled execution.

If you would like to read more from the STABILITY study click here

 

References

1. Getgood A, Bryant D, Litchfield R, et al. Am J Sports Med. 2020;48(2):285–297.
2. Getgood A. Clin Sports Med. 2024;43(2):367–381.
3. Firth AD, Bryant DM, Litchfield R, et al. Am J Sports Med. 2022; 50(2):384-395
4. Saithna A, Geeslin A, Sonnery-Cottet B. Arthroscopy. 2025;41(9):3300–3302.
5. Sonnery-Cottet B, Carrozzo A, Saithna A, et al. Arthroscopy. 2025; 41(9):3303–3312.
6. Sonnery-Cottet B, Carrozzo A, Saithna A, et al. Arthroscopy. 2025; 41(9):3313–3321.