Sports MedicineKneeSurgery Center

Lateral Extra-Articular Tenodesis (LET)

An evidence-based augmentation that significantly reduces ACL graft failure — performed by fellowship-trained sports medicine surgeons at our Bethesda and Germantown locations.

Duration: 15–25 minutes (added to ACL reconstruction)Anesthesia: General or regional

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What is lateral extra-articular tenodesis (let)?

Lateral extra-articular tenodesis (LET) is a secondary knee stabilization procedure performed alongside ACL reconstruction. It controls the rotational instability that standard ACL grafts alone cannot fully correct, and clinical trial data show it reduces graft re-tear rates by up to 67% in high-risk patients such as young athletes using hamstring grafts.

Why this approach — at MOS

Our approach to LET is grounded in the published evidence and applied selectively — not added to every ACL reconstruction. The STABILITY trial results are clear, but they were generated specifically in patients under 25 years of age using hamstring autograft with a positive pivot-shift. Those criteria guide our patient selection.

We use the modified Lemaire technique as the foundation, with the graft passed deep to the lateral collateral ligament as the anatomy dictates. Fixation angle and tension are standardized based on the STABILITY trial protocol to replicate the trial outcomes in clinical practice.

For patients undergoing revision ACL reconstruction, LET becomes an even stronger consideration. Data from the SANTI Study Group demonstrate that revision ACL combined with a lateral extra-articular procedure produces superior rotational stability and significantly lower re-failure rates compared to isolated intra-articular revision, without meaningful differences in patient-reported outcome scores or return-to-sport rates.

We do not add LET to all BPTB graft reconstructions. The bone-to-bone healing of the patellar tendon graft, combined with its well-established rotational control properties, means the marginal benefit of LET in that population is not yet demonstrated with the same level of evidence.

For elite and competitive athletes in high-risk sports — soccer, basketball, football, lacrosse — where the consequences of graft failure are career-defining, LET is part of our standard conversation and our strong recommendation when the clinical criteria are met.

Who is a candidate?

Indications

LET is recommended — not universal — and is most beneficial in patients with specific risk factors for graft failure. At Maryland Orthopedic Specialists, we consider LET for patients who have:

Age under 25 years — younger patients have significantly higher biological activity levels, longer careers ahead, and the highest documented graft re-tear rates
Hamstring tendon autograft — the graft type with the highest re-tear risk in young athletes, for which the STABILITY trial was specifically designed. That is also why we rarely use this graft
Pre-operative pivot-shift grade II or III — a clinical examination finding indicating meaningful rotational laxity before surgery
High-demand sport participation — contact or cutting sports (soccer, basketball, football, rugby, lacrosse, skiing, gymnastics) where the knee faces repeated high-load rotational stress
Generalized ligamentous laxity — patients with hypermobile joints are at higher risk for graft failure
High BMI combined with high activity level — greater mechanical load on the graft during early healing
Revision ACL reconstruction — patients undergoing a second ACL surgery who have already failed one intra-articular graft, where controlling rotational instability becomes even more critical
Contralateral ACL history — having torn the opposite ACL is an independent predictor of graft failure

Contraindications

LET may not be appropriate for:

Low-demand or older patients where the small added rotational control does not justify the additional surgical step
Patients using bone-patellar tendon-bone autograft for primary ACL reconstruction — the BPTB graft provides superior rotational control on its own, and the added benefit of LET is less well-established in this population
Patients with a tight iliotibial band or pre-existing lateral knee pain, where using the IT band may worsen symptoms
Significant lateral compartment arthritis, where altering lateral-side mechanics could accelerate joint wear

Conservative Treatment First

ACL tears require surgery in patients who wish to return to cutting or pivoting sports. There is no non-surgical treatment that restores the structural ACL. However, before adding LET to an ACL reconstruction, your surgeon will conduct a thorough assessment of your specific risk profile — not every ACL patient needs or benefits from LET. The decision is individualized based on age, graft choice, sport, examination findings, and your personal goals.

The procedure

What Is Lateral Extra-Articular Tenodesis?

Lateral extra-articular tenodesis (LET) is a secondary stabilization procedure added to ACL reconstruction that controls abnormal rotational movement in the knee — a specific type of instability that an intra-articular ACL graft alone cannot fully eliminate. The procedure takes an additional 15 to 25 minutes at the end of ACL reconstruction and adds no separate incision in most technique variations.

The core problem LET solves is the pivot-shift phenomenon. When the ACL is torn, the tibia can shift forward and rotate inward under load — a motion that patients often describe as the knee "giving way" during cutting, pivoting, or landing. Standard ACL grafts restore forward stability effectively, but residual rotational laxity persists in a meaningful number of patients, particularly young athletes whose high-demand activities place extreme stress on the newly reconstructed joint during the critical early months before full graft incorporation.

LET works by reconstructing a restraint on the lateral (outer) side of the knee using a strip of the iliotibial band, which is rerouted and fixed to the lateral femoral condyle. This creates an extra-articular check against internal tibial rotation, working in parallel with — not in place of — the intra-articular ACL graft. The two stabilizing structures complement each other: the ACL graft controls anterior-posterior translation, and the LET controls rotational laxity.

The evidence supporting LET is among the most rigorous in sports medicine. The STABILITY Study — a multicenter randomized clinical trial — demonstrated that adding LET to hamstring tendon ACL reconstruction reduced graft re-tear rates by 67% in young, active patients at two-year follow-up, without increasing complication rates. This level of evidence has led to widespread adoption among high-volume ACL surgeons in North America and Europe.

What Happens During Lateral Extra-Articular Tenodesis?

LET is performed immediately after ACL reconstruction is completed, with the patient still under anesthesia. No separate trip to the operating room is needed.

Setup: The patient remains in the same supine position used for ACL reconstruction. The knee is slightly flexed and the leg is prepped to allow access to the lateral (outer) side of the knee.

Identifying the iliotibial band: A small additional incision of approximately 2 to 3 centimeters is made over the lateral femoral condyle — the bony prominence on the outer side of the knee just above the joint line. In some technique variations, the LET can be performed through the same portal or incision already used for the ACL portion of the procedure.

Harvesting the graft strip: The surgeon identifies the iliotibial band — the broad tendinous structure running down the outer thigh — and carefully isolates a strip approximately 1 centimeter wide from its posterior third. This strip is elevated at its proximal (upper) end while its distal attachment at Gerdy's tubercle on the tibia is preserved. The IT band continues to function normally after this partial harvest.

Routing the graft: The freed strip is then passed deep to the lateral collateral ligament — threading it beneath this structure is critical to achieving the rotational check the procedure is designed to provide. Passing it superficial to the LCL would not control internal tibial rotation effectively.

Fixation: With the knee held at approximately 60 to 90 degrees of flexion and the tibia in neutral rotation, the graft strip is fixed to the lateral femoral condyle using a small suture anchor or a staple. This fixation position is carefully chosen to avoid over-constraining the knee — the LET should limit excessive internal rotation under load without restricting normal range of motion.

Closure: The small lateral incision is closed in layers and the knee is dressed and placed in a brace before the patient leaves the operating room.

The entire LET addition typically adds 15 to 25 minutes to the ACL reconstruction operative time.

Recovery timeline

Weeks 1–2

Knee brace locked in extension for walking, crutches for assistance. Emphasis on quad activation, swelling control, and restoring full extension. The lateral incision heals quickly.

Weeks 2–6

Progressive weight-bearing without crutches. Range of motion restoration, stationary cycling, pool walking. Brace weaned as quad strength and swelling allow.

Months 2–4

Closed-chain strengthening, single-leg press, hip and core strengthening. No cutting or pivoting. Light jogging on a straight line begins when single-leg squat form is adequate.

Months 4–6

Sport-specific conditioning, agility work, running program progression. Return-to-sport testing battery initiated.

Months 9–12

Criteria-based return to unrestricted competition. Clearance is based on passing a validated return-to-sport test battery — not simply time elapsed. Limb symmetry index targets for quad and hamstring strength, single-leg hop tests, and psychological readiness are all assessed.

The LET does not add to the biological healing timeline. The limiting factor in ACL reconstruction recovery is graft ligamentization — the process by which the graft transforms into functional ligament tissue — which takes 9 to 12 months regardless of whether LET is added. The small lateral incision from the LET heals within 2 to 3 weeks and is rarely a source of prolonged symptoms.

A small subset of patients reports temporary lateral-side tightness or sensitivity over the IT band harvest site in the first 4 to 6 weeks, which resolves with physical therapy. Over-the-counter anti-inflammatory medications and targeted IT band stretching address this effectively in the vast majority of cases.

Physical therapy through our in-house rehabilitation program at Maryland Orthopedic Specialists follows a structured, criteria-based protocol from day one through return to sport. Progression is tied to measurable milestones, not a calendar.

Frequently Asked Questions

Does everyone who has ACL reconstruction need LET?

No — LET is recommended for specific patients with risk factors for graft failure, not as a routine addition to every ACL reconstruction. The patients who benefit most are young athletes (under 25), those using a hamstring autograft, those with a significant pivot-shift on pre-operative examination, and those returning to high-demand cutting or contact sports. Your surgeon will assess your individual risk profile at your consultation.

Will LET limit my knee movement or make my knee feel stiff?

When performed correctly with appropriate fixation angle and tension, LET does not restrict normal knee range of motion. The STABILITY randomized trial specifically measured range of motion outcomes and found no significant difference between patients who had LET added and those who did not. A small number of patients notice temporary lateral-side tightness in the early weeks after surgery, which resolves with physical therapy.

Does adding LET make recovery longer?

No. The recovery timeline is set by the ACL reconstruction itself — specifically the time required for graft ligamentization, which takes 9 to 12 months. LET does not extend this. The small lateral incision from LET heals within 2 to 3 weeks and does not delay rehabilitation milestones.

What is the pivot-shift test and why does it matter for LET decisions?

The pivot-shift test is a clinical examination maneuver in which the surgeon applies a combination of axial load and internal rotation to the knee while bringing it from flexion to extension. A positive result — where the tibia shifts forward and then clunks back — indicates rotational laxity beyond what the ACL alone is controlling. Patients with grade II or III pivot-shift pre-operatively are at the highest risk for graft failure and derive the greatest absolute benefit from LET augmentation based on the STABILITY trial subgroup data.

I've already had one ACL reconstruction that failed. Does LET help in revision surgery?

Yes — this is one of the strongest indications for LET. Patients undergoing revision ACL reconstruction have already demonstrated that an isolated intra-articular graft was insufficient for their knee. Data from the SANTI Study Group show that adding a lateral extra-articular procedure to revision ACL reconstruction produces significantly better rotational stability and lower re-failure rates than isolated intra-articular revision, without affecting return-to-sport rates. If you are planning a revision ACL, LET should be part of the conversation with your surgeon.

Is LET the same as anterolateral ligament (ALL) reconstruction?

Not exactly — they address the same problem (rotational instability) through different approaches. LET uses a strip of the patient's own iliotibial band rerouted to create an extra-articular restraint, while ALL reconstruction attempts to reconstruct the specific anterolateral ligament using a separate graft. Both have evidence supporting their effectiveness. LET has the most robust randomized controlled trial data (the STABILITY trial), while ALL reconstruction has a growing body of supporting literature. At MOS, we primarily use the LET technique based on the strength of the STABILITY evidence.

What is the re-tear rate with LET compared to without it?

In the STABILITY trial — the most rigorous study available — the graft re-tear rate was 4.1% with LET versus 12.1% without LET at two years, representing a 67% relative risk reduction. It is important to understand this was in a specific population: patients under 25 using hamstring autograft with a positive pivot-shift. Results in lower-risk populations would differ. Your surgeon will discuss what your specific re-tear risk profile looks like and how much LET is expected to reduce it for you individually.

How does LET affect long-term knee health?

This was a concern with earlier versions of the procedure — that altering lateral-side mechanics might accelerate lateral compartment arthritis. The adverse-event analysis from the STABILITY trial, published in the Journal of ISAKOS, found no increase in complications, stiffness, or secondary procedures in the LET group at two-year follow-up. Longer-term data are accumulating. The current evidence does not support the concern that LET causes early lateral compartment degeneration when performed correctly.

Medically reviewed by Christopher S. Raffo, MD

Last reviewed June 4, 2026