High-yield overview
Anterolateral Complex of the Knee
Pivot shiftAnterolateral rotatory control
SegondLateral capsular/ALL avulsion
LET / ALLRExtra-articular augment to ACLR
40%->25%STABILITY: clinical failure reduced
Key features
Anatomy/function
PatternThe ANTEROLATERAL LIGAMENT (ALL)/anterolateral complex (with the iliotibial band/Kaplan fibres) is a secondary restraint to INTERNAL ROTATION of the tibia - it controls the ANTEROLATERAL ROTATORY instability seen as the PIVOT SHIFT, working with the ACL.
Treatment
Segond fracture
PatternA SEGOND FRACTURE is a small avulsion off the LATERAL tibial plateau margin (lateral capsular/ALL avulsion) - a near-pathognomonic radiographic marker of an ACL/anterolateral injury that should prompt MRI and assessment of rotatory stability.
Treatment
Augmentation
PatternLATERAL EXTRA-ARTICULAR TENODESIS (LET, e.g. modified Lemaire using an iliotibial-band strip) or ALL RECONSTRUCTION supplements ACL reconstruction to control the pivot shift and reduce graft failure in HIGH-RISK patients.
Treatment
Critical Must-Knows
- The ANTEROLATERAL LIGAMENT (ALL) and the wider anterolateral complex - which includes the iliotibial band and its deep Kaplan fibre attachments to the distal femur - act as SECONDARY restraints to INTERNAL ROTATION of the tibia, controlling the anterolateral rotatory instability that is clinically detected as the PIVOT SHIFT; they work alongside the ACL, which is the primary restraint to anterior translation.
- The SEGOND FRACTURE is the radiographic signature of anterolateral injury: a small elliptical bony AVULSION off the LATERAL margin of the proximal tibial plateau (a lateral capsular/anterolateral structure avulsion), and it is near-pathognomonic of an ACL tear - so a Segond fracture on a knee radiograph should prompt MRI and careful assessment of rotatory stability.
- After ACL reconstruction, residual ANTEROLATERAL ROTATORY INSTABILITY (a persistent pivot shift) and graft failure are problems particularly in HIGH-RISK patients, which is the rationale for adding an EXTRA-ARTICULAR procedure - either a LATERAL EXTRA-ARTICULAR TENODESIS (LET) or an ANTEROLATERAL LIGAMENT RECONSTRUCTION - to the intra-articular ACL graft to better control the pivot shift.
- The INDICATIONS for adding LET/ALL reconstruction to ACLR are high-risk features: young age (under about 25), generalised LIGAMENTOUS LAXITY/hyperlaxity, a high-grade (grade 2 or greater) PIVOT SHIFT, REVISION ACL reconstruction or previous graft failure, elite athletes in CUTTING/PIVOTING sports, and an increased posterior TIBIAL SLOPE.
- The EVIDENCE is strong: in the STABILITY randomised controlled trial, adding LET to a hamstring-autograft ACL reconstruction reduced clinical failure from about 40% to 25% and graft rupture from about 11% to 4% at 2 years, with similar return-to-sport rates; meta-analyses confirm reduced graft failure and reduced postoperative anterolateral rotatory instability with the addition of an extra-articular procedure.
- TECHNIQUE (LET, modified Lemaire): a strip of the iliotibial band is harvested (left attached distally at Gerdy's tubercle), passed DEEP to the lateral collateral ligament, and fixed to the distal femur approximately proximal-and-posterior to the lateral epicondyle with the knee around 60 degrees of flexion in neutral rotation; the iliotibial band is then repaired - the downsides are reported to be minimal, though long-term osteoarthritis is being monitored.
Clinical Pearls
- “Anterolateral complex (ALL + IT band/Kaplan fibres) = secondary restraint to internal rotation -> controls the PIVOT SHIFT (works with the ACL).
- “SEGOND fracture = lateral tibial plateau avulsion = near-pathognomonic of ACL/anterolateral injury -> MRI + assess rotatory stability.
- “Add LET (modified Lemaire) or ALL reconstruction to ACLR in HIGH-RISK patients (young, hyperlax, high-grade pivot, revision, pivoting athletes, steep slope). STABILITY trial: clinical failure 40%->25%, graft rupture 11%->4%.
Control the Pivot Shift, Not Just the Translation
The complex
The anterolateral complex (ALL + IT band/Kaplan fibres) restrains internal rotation - the pivot shift. A Segond fracture is its avulsion signature (and a marker of ACL injury).
The augment
Add LET (modified Lemaire) or ALL reconstruction to ACLR in high-risk patients - the STABILITY trial showed less graft failure and clinical failure.
Anatomy, the Segond Fracture & the Pivot Shift
The Anterolateral Complex and Its Avulsion Signature
The anterolateral ligament and the anterolateral complex (the iliotibial band with its deep Kaplan fibres) are secondary restraints to internal rotation of the tibia, controlling the anterolateral rotatory instability detected as the pivot shift - they work with the ACL (the primary restraint to anterior translation). The radiographic signature of anterolateral injury is the Segond fracture: a small elliptical avulsion off the lateral tibial plateau margin, near-pathognomonic of an ACL tear, which should prompt MRI and assessment of rotatory stability. Because residual pivot shift and graft failure remain problems after ACL reconstruction - especially in high-risk patients - an extra-articular procedure (LET or ALL reconstruction) is added to better control the pivot shift.
Augmentation: LET & ALL Reconstruction
When and How to Add an Extra-Articular Procedure
- Indications (high-risk): young age (under ~25), generalised ligamentous laxity, high-grade (grade 2+) pivot shift, revision ACLR or previous graft failure, elite cutting/pivoting athletes, and increased posterior tibial slope.
- LET (modified Lemaire): harvest a strip of iliotibial band (left attached distally at Gerdy's tubercle), pass it deep to the LCL, and fix it to the distal femur ~proximal-and-posterior to the lateral epicondyle with the knee at ~60 degrees flexion in neutral rotation; repair the IT band.
- ALL reconstruction: an anatomic graft reconstruction of the anterolateral ligament is an alternative extra-articular augment.
- Evidence: the STABILITY RCT showed LET reduced clinical failure (about 40% to 25%) and graft rupture (about 11% to 4%) at 2 years; avoid isolated soft-tissue grafts in high-risk patients - add an extra-articular procedure.
In the High-Risk Knee, the Pivot Shift Is the Enemy
The key modern lesson in ACL surgery is that, in high-risk knees, controlling the anterolateral rotatory instability - the pivot shift - is as important as restoring anterior translation, because a residual pivot shift and graft failure are concentrated in young, hyperlax patients, those with a high-grade pivot, revisions and pivoting athletes. In these patients an isolated intra-articular ACL graft, especially a soft-tissue graft, is more likely to fail, and adding an extra-articular procedure - LET or ALL reconstruction - significantly reduces graft failure and clinical failure (STABILITY trial). A Segond fracture is a useful flag that the anterolateral complex is involved. The downsides of LET appear minimal, but long-term osteoarthritis should be monitored, so reserve the augment for the genuinely high-risk patient rather than applying it indiscriminately.
Evidence & Key Studies
Evidence
Lateral extra-articular tenodesis as an adjunct to ACL reconstruction (indications, technique, STABILITY data)
McGovern MM, Yalcin S, Lowenstein NA, Mazzocca JL, Matzkin EG, Medina G • Video Journal of Sports Medicine (2025)
Key Findings:
- LET supplements internal rotational stability and reduces the pivot shift; indications include age under 25, increased posterior tibial slope, ligamentous laxity, elite cutting/pivoting athletes, grade 2 or greater pivot shift, and prior ACL graft failure.
- In the STABILITY randomised controlled trial, adding LET to hamstring-autograft ACLR reduced 2-year clinical failure from 40% to 25% and graft rupture from 11% to 4%, with a similar return-to-sport rate.
- A meta-analysis of ACLR versus ACLR plus LET reported reduced graft failure and reduced postoperative anterolateral rotatory instability.
Evidence
Extra-articular procedures (ALL reconstruction/LET) improve ACLR outcomes in high-risk patients
van der List JP • Arthroscopy (2025)
Key Findings:
- Outcomes of ACL reconstruction were historically disappointing in high-risk populations (generalised ligament laxity, pivoting athletes) with low return-to-sport rates, incomplete restoration of rotatory stability and relatively high osteoarthritis rates.
- A renewed focus on extra-articular procedures (anterolateral ligament reconstruction and lateral extra-articular tenodesis) and avoiding isolated soft-tissue grafts in high-risk patients has significantly improved outcomes.
- Indications for extra-articular procedures have expanded with apparently minimal downsides, though long-term osteoarthritis should be monitored.
Evidence Attribution
According to PubMed, the role of LET (supplementing internal rotational stability/reducing pivot shift), its indications, the STABILITY-trial outcomes (clinical failure 40% to 25%, graft rupture 11% to 4%) and the supporting meta-analysis come from the cited McGovern article; the improvement in high-risk ACLR outcomes with extra-articular procedures (ALL reconstruction/LET), the avoidance of isolated soft-tissue grafts in high-risk patients and the need to monitor long-term osteoarthritis from the cited van der List commentary. The anterolateral complex anatomy, the Segond fracture and the pivot-shift mechanism are standard, well-established teaching. (See also our ACL Reconstruction and Pivot Shift / Knee Examination topics.)
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
Viva scenarioStandard
Clinical prompt
“What is the anterolateral complex of the knee, and what is a Segond fracture?”
Practical approach
The anterolateral complex of the knee comprises the anterolateral ligament and the iliotibial band with its deep Kaplan fibre attachments to the distal femur, and functionally these structures are secondary restraints to internal rotation of the tibia. They control the anterolateral rotatory instability that we detect clinically as the pivot shift, working alongside the ACL, which is the primary restraint to anterior translation. A Segond fracture is the radiographic signature of injury to this complex: it is a small elliptical avulsion fragment off the lateral margin of the proximal tibial plateau, representing avulsion of the lateral capsular and anterolateral structures, and it is near-pathognomonic of an ACL tear. So if I see a Segond fracture on a knee radiograph, I treat it as a strong marker of an ACL injury with anterolateral involvement, and I would obtain an MRI and carefully assess rotatory stability, including the pivot shift. The clinical importance of the anterolateral complex is that residual pivot shift and graft failure after ACL reconstruction, particularly in high-risk patients, have driven the addition of extra-articular procedures such as lateral extra-articular tenodesis or anterolateral ligament reconstruction to better control rotation.
Key clinical points
Anterolateral complex = ALL + IT band/Kaplan fibres; secondary restraint to internal rotation (pivot shift)
Works with the ACL (primary restraint to anterior translation)
Segond fracture = lateral tibial plateau avulsion = near-pathognomonic of ACL injury
Segond -> MRI + assess rotatory (pivot-shift) stability
Common pitfalls
Ignoring a Segond fracture (it signals ACL/anterolateral injury)
Thinking only of anterior translation and forgetting rotation
Confusing the Segond (lateral) with the medial-sided avulsions
Further questions
“What does the anterolateral complex restrain? - Internal rotation (the pivot shift)”
“Where is the Segond avulsion? - The lateral margin of the proximal tibial plateau”
Viva scenarioStandard
Clinical prompt
“When would you add a lateral extra-articular tenodesis to an ACL reconstruction, and what does the evidence show?”
Practical approach
I would add a lateral extra-articular tenodesis, or alternatively an anterolateral ligament reconstruction, to an ACL reconstruction in high-risk patients, because in these the pivot shift and graft failure are the main problems. The high-risk features are young age, under about 25, generalised ligamentous laxity, a high-grade pivot shift of grade 2 or more, revision ACL reconstruction or previous graft failure, elite athletes in cutting or pivoting sports, and an increased posterior tibial slope. The rationale is that an isolated intra-articular graft, especially a soft-tissue graft, may not fully control the anterolateral rotatory instability in these knees, so supplementing it with an extra-articular procedure better controls the pivot shift. The evidence is strong: in the STABILITY randomised controlled trial, adding a lateral extra-articular tenodesis to a hamstring-autograft ACL reconstruction reduced two-year clinical failure from about 40 percent to 25 percent and graft rupture from about 11 percent to 4 percent, with a similar return-to-sport rate, and meta-analyses confirm reduced graft failure and reduced postoperative anterolateral rotatory instability. Technically, the modified Lemaire tenodesis uses an iliotibial-band strip passed deep to the lateral collateral ligament and fixed to the distal femur proximal and posterior to the lateral epicondyle with the knee at about 60 degrees of flexion in neutral rotation. The downsides appear minimal, though long-term osteoarthritis is being monitored, so I reserve it for genuinely high-risk patients.
Key clinical points
Indications: young, hyperlax, grade 2+ pivot shift, revision/graft failure, pivoting athletes, steep tibial slope
Rationale: better control of anterolateral rotatory instability (pivot shift)
STABILITY RCT: clinical failure 40%->25%, graft rupture 11%->4% at 2 years
Modified Lemaire: IT-band strip deep to LCL, fixed proximal-posterior to lateral epicondyle (~60 deg, neutral rotation)
Common pitfalls
Using an isolated soft-tissue graft alone in a high-risk knee
Applying LET indiscriminately (reserve for high-risk; monitor OA)
Mis-tensioning (wrong flexion angle/rotation) the tenodesis
Further questions
“Key STABILITY-trial result? - Reduced graft rupture (11%->4%) and clinical failure (40%->25%)”
“Where is LET fixed on the femur? - Proximal and posterior to the lateral epicondyle”
Mnemonics & Memory Aids
Mnemonic
PIVOT
P
Pivot shift = anterolateral rotatory instability (the target)
I
Internal rotation restrained by the anterolateral complex
V
Very high-risk: young, hyperlax, grade 2+ pivot, revision, pivoting athlete, steep slope
O
Outcomes improved: STABILITY (failure 40%->25%, rupture 11%->4%)
T
Tenodesis (LET, modified Lemaire) or ALL reconstruction; Segond fracture = the flag
Hook:PIVOT: Pivot shift target, Internal rotation restraint, Very high-risk indications, Outcomes improved (STABILITY), Tenodesis/ALLR (Segond flag).
Exam day cheat sheet
ALL Injury & LET - Exam Day Cheat Sheet
Anatomy & function
- Anterolateral complex = ALL + IT band/Kaplan fibres
- Secondary restraint to internal rotation -> controls the pivot shift
- Works with the ACL (primary restraint to anterior translation)
Segond fracture
- Small avulsion off the lateral tibial plateau margin
- Near-pathognomonic of an ACL tear / anterolateral injury
- Prompt MRI and assessment of rotatory stability
Indications to augment ACLR
- Young (under ~25), generalised ligamentous laxity
- High-grade (grade 2+) pivot shift; revision/graft failure
- Elite cutting/pivoting athletes; increased posterior tibial slope
LET & evidence
- Modified Lemaire: IT-band strip deep to LCL, fixed proximal-posterior to lateral epicondyle (~60 deg, neutral rotation)
- ALL reconstruction is an alternative extra-articular augment
- STABILITY RCT: clinical failure 40%->25%, graft rupture 11%->4%; monitor long-term OA