Technical Note

Anterolateral Ligament Reconstruction Technique:An Anatomic-Based Approach

Jorge Chahla, M.D., Travis J. Menge, M.D., Justin J. Mitchell, M.D., Chase S. Dean, M.D.,and Robert F. LaPrade, M.D.

Abstract: Restoration of anteroposterior laxity after an anterior cruciate ligament reconstruction has been predictablewith traditional open and endoscopic techniques. However, anterolateral rotational stability has been difficult to achievein a subset of patients, even with appropriate anatomic techniques. Therefore, differing techniques have attempted toaddress this rotational laxity by augmenting or reconstructing lateral-sided structures about the knee. In recent years,there has been a renewed interest in the anterolateral ligament as a potential contributor to residual anterolateral rotatoryinstability in anterior cruciate ligamentedeficient patients. Numerous anatomic and biomechanical studies have beenperformed to further define the functional importance of the anterolateral ligament, highlighting the need for surgicaltechniques to address these injuries in the unstable knee. This article details our technique for an anatomic anterolateralligament reconstruction using a semitendinosus tendon allograft.

Anterior cruciate ligament (ACL) tears requiringsurgical intervention are commonly encountered

in young athletes, and it is estimated that 200,000 ACLreconstructions are performed each year in the UnitedStates. Whereas technological advances have allowedfor endoscopic ACL reconstruction, these injuries werehistorically treated with lateral extra-articular tenodesisprocedures to prevent both anterolateral rotatoryinstability and anterior tibial translation.1 Despite theearly enthusiasm for these techniques, they subse-quently fell out of favor because they did not reproducethe native anatomy, and long-term outcome studiesreported residual instability, overconstraint of thelateral compartment, and graft failure.2-5

However, recent publications have stimulatedrenewed discussion regarding the anterolateral soft-tissue structures of the knee. In 2013 Claes et al.6

described the anatomic location and function of theanterolateral ligament (ALL). This work built on priorstudies by numerous authors who have described anextra-articular structure in the lateral knee extendingfrom the lateral epicondyle of the femur to the lateraltibia that may contribute to translational and rotatorystability in conjunction with the ACL.7,8 Although pre-viously recognized, the “rediscovery” of the synergisticrelation between the anterolateral structures and ACL incontrolling anterolateral rotatory stability has led torenewed interest in lateral extra-articular tenodesisprocedures9 and specifically reconstruction of the ALL.Biomechanical studies have shown that the ALL is an

important stabilizer of internal rotation at knee flexionangles greater than 35!; however, it has limited func-tion in resisting anterior translation.10 This stabilizingfunction may account for a small subset of patients whohave continued anterolateral rotatory instability, asshown by a positive pivot-shift examination, after anappropriately performed ACL reconstruction. In thissmall subset of patients, ALL reconstruction can provideincreased knee stability and allow for improved kneefunction. The purpose of this study was to describe ourtechnique for an anatomic ALL reconstruction.

Surgical Technique

Operative IndicationsSurgical indications for ALL reconstruction include a

3þ pivot shift in an ACL-deficient knee and cases of

From Steadman Philippon Research Institute (J.C., T.J.M., J.J.M., C.S.D.,R.F.L.); and The Steadman Clinic (T.J.M., J.J.M., R.F.L.), Vail, Colorado,U.S.A.

The authors report the following potential conflict of interest or source offunding: R.F.L. receives support from Arthrex; Smith & Nephew; Ossur;Health East, Norway; and an NIH R13 grant for biologics.

Received December 14, 2015; accepted January 21, 2016.Address correspondence to Robert F. LaPrade, M.D., Steadman Philippon

Research Institute, The Steadman Clinic, 181 W Meadow Dr, Ste 400, Vail,CO 81657, U.S.A. E-mail: drlaprade@sprivail.org

! 2016 by the Arthroscopy Association of North America2212-6287/151178/$36.00http://dx.doi.org/10.1016/j.eats.2016.01.032

Arthroscopy Techniques, Vol -, No - (Month), 2016: pp e1-e5 e1

multiple revision ACL reconstructions with residualpivot shift and continued clinically significant instabilityafter ACL reconstruction. In all cases, other causes ofincreased anterolateral rotation on the pivot shift, suchas a deficient lateral meniscus or a concurrentposterolateral knee injury, should be ruled out.

Patient Positioning and AnesthesiaThe patient is placed in a supine position with the

injured leg in a leg holder (Mizuho OSI, Union City,CA), with the nonsurgical leg flexed, abducted, andheld in an abduction holder (Birkova Products, Goth-enburg, NE) (Video 1). A well-padded thigh tourniquetis subsequently placed on the upper thigh of the oper-ative leg. The surgical leg is prepared and draped in theusual sterile fashion, the leg is exsanguinated, and thetourniquet is inflated.

ALL ReconstructionAfter confirmation of significant anterolateral rotatory

instability, an ALL reconstruction is undertaken. A lateralhockey-stick incision is made through the skin along theiliotibial band (ITB) and is extended distally between thelateral fibular head and Gerdy’s tubercle (Fig 1).Sharp dissection is performed down to the fascia

overlying the ITB. Full-thickness skin flaps with sub-cutaneous tissue are made anteriorly and posteriorly.The posterior skin flap should have sufficient subcu-taneous tissue and vascularity to support wound heal-ing and avoid skin necrosis postoperatively. Becausethis surgical procedure is often performed in revisionsettings, adhesions can be encountered and carefuldissection should be performed.The joint line is then identified with the aid of a spinal

needle. The tibial attachment site of the ALL is identi-fied, equidistant between the center of the Gerdy tu-bercle and the anterior margin of the fibular head,9.5 mm distal to the joint line11 (Fig 2).

Subsequently, dissection of the soft tissues down tothe bone is performed. With the assistance of an ACLaiming device, a guide pin is placed at the distalanatomic insertion aiming toward the superomedialtibia (Fig 3). A 6-mm-diameter reamer (Arthrex,Naples, FL) is used to create a tunnel to a depth of30 mm.Next, a path is created underneath the superficial

layer of the ITB using gentle blunt dissection. A prox-imal exit point is created slightly posterior to theproximal fibular collateral ligament (FCL) attachment(identified by applying valgus force to the knee) bymaking a 3-cm incision through the superficial layer ofthe ITB. The ALL’s femoral attachment is located 4.7mm proximal and posterior to the FCL’s femoralinsertion as described by Kennedy et al.11 An eyelet pinis drilled into the femur, aiming anteriorly and proxi-mally to avoid the trochlea and a potential collisionwith an ACL tunnel (Fig 4).

Fig 1. A left knee with a superimposed schematic view of theanatomic landmarks and the surgeon’s incision outline. (ALL,anterolateral ligament.)

Fig 2. Identification of the joint line is achieved with the aidof a spinal needle in a left knee. The tibial attachment site ofthe anterolateral ligament (ALL) is located equidistant be-tween the center of Gerdy’s tubercle and the anterior marginof the fibular head (9.5 mm distal to the joint line11).

Fig 3. An anterior cruciate ligament aiming device is used in aleft knee to position the tibial tunnel. A guide pin is placed atthe anatomic attachment aiming toward the superomedialtibia.

e2 J. CHAHLA ET AL.

A closed-socket tunnel is created with a 6-mm reamer(Arthrex), again to a depth of 30 mm. The tunnel isthen tapped to prevent graft injury during interferencescrew fixation due to the hard cortical bone in the fe-mur at this location. The inter-tunnel distance ismeasured to prepare the graft length accordingly(Fig 5). In our hands, it is usually 11 cm long.

Graft PreparationA semitendinosus tendon allograft (Allosource,

Centennial, CO) is used and prepared based on thepreviously measured inter-tunnel (femoral and tibial)distances with the addition of 25 mm on each end forthe tunnels. Both ends are whipstitched and tubular-ized (25 mm) with No. 2 polyethylene-polyester suture(FiberWire; Arthrex). The redundant tissue can then be

excised (Fig 6). Alternatively, a semitendinosus auto-graft can also be used if it was not previously harvested.

ALL Graft Passage and FixationThe graft is fixed distally in the tibia with a 7 #

23emm Bio-Interference screw (Arthrex). Traction isapplied to the graft to ensure sturdy fixation (Fig 7).The graft is then passed between the superficial layerof the ITB and FCL (Fig 8). Lastly, the graft is insertedinto the femoral tunnel with the help of the previ-ously placed passing suture and secured with a 7 #23emm Bio-Interference screw in 30! of knee flexion(Fig 9).Once fixation is complete, the knee is assessed

through a complete range of motion and rotationalstability is tested with the pivot-shift test for comparisonto the preoperative state. Pearls and pitfall of this sur-gical technique are summarized in Table 1.

Fig 4. The anterolateral ligament (ALL) courses superficiallyto the fibular collateral ligament (FCL), and its femoralattachment is located 4.7 mm proximal and posterior to theFCL’s femoral insertion as described by Kennedy et al.,11 asshown in the anatomic picture on the right (left knee). Asshown on the left, an eyelet pin is drilled into the femur,aiming anteriorly and proximally on the femoral anatomicattachment in a left knee.

Fig 5. The inter-tunnel distance (femoral to tibial tunnel) ismeasured to prepare the graft accordingly in a left knee.

Fig 6. Prepared semitendinosus tendon allograft. Both endsare whipstitched with FiberWire suture. The size of the allo-graft depends on the inter-tunnel distance (femoral to tibialtunnel) previously measured.

Fig 7. The graft is fixed in the tibial tunnel with a 7 # 23emmBio-Interference screw in a left knee.

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Postoperative RehabilitationAfter surgery, the patient is allowed to bear weight

immediately and there are no restrictions on range ofmotion. Crutches are used as needed for the first4 weeks postoperatively or until the patient iscomfortable walking without assistance. As soon as thepatient can perform a straight leg raise without anextension lag, he or she can discontinue using a kneeimmobilizer and be placed into an ACL brace (CTibrace; Ossur, Reykjavik, Iceland). A supervised physicaltherapy program is prescribed for 3 months. Becausemost patients who qualify for an ALL reconstructionalso undergo a concurrent ACL revision reconstruction,the postoperative ACL revision protocol will most oftendictate the ongoing rehabilitation program. Physicaltherapy is designed to emphasize early range of motionand strengthening exercises.

DiscussionThis article details our technique for an anatomic ALL

reconstruction of the knee. Once thought of as simply acapsular thickening without a well-defined biome-chanical role, there has been renewed interestregarding this structure in recent years, with a numberof studies evaluating its incidence of injury, anatomic

features, biomechanical properties, and functional roleas a lateral stabilizer of the tibiofemoral joint.11 As ourknowledge on treatment of the unstable knee continuesto evolve, we recommend anatomic reconstruction ofthe ALL in cases with residual anterolateral rotatoryinstability on the pivot-shift test after or in conjunctionwith an ACL reconstruction to restore native knee ki-nematics and improve patient outcomes.Segond12 first described an avulsion fracture pattern

of the proximal-lateral tibia in 1879, which was re-ported to have a pathognomonic association with ACLtears over 100 years later.13,14 Until recently, theanatomic structure responsible for this bony avulsionpattern was poorly understood.15,16 Reports of thepresence of a distinct structure with well-defined originand insertion sites began to emerge in the early 21stcentury; it was termed the “anterolateral ligament.”6

Further studies showed the ALL to play an importantrole in anterior and rotational stability about the knee,especially in cases with concomitant ACL injuries.10

Residual anterolateral rotatory instability after ACLreconstruction led to a renewed interest in the func-tional role of the ALL and the development of surgicaltechniques to address this pathology.LaPrade et al.11 performed an anatomic, radiographic,

and biomechanical analysis of the structural propertiesof the ALL. They found the femoral origin was located4.7 mm posterior and proximal to the FCL attachmentand then coursed distally to attach at the anterolateraltibia midway between the Gerdy tubercle and theanterior margin of the fibular head.11 On ante-roposterior radiographs, the ALL originated on the fe-mur 22.3 mm proximal to the joint line and inserted on

Fig 8. The semitendinosus allograft is being passed deep tothe superficial layer of the iliotibial (IT) band in a left knee.

Fig 9. With the knee in 30! of flexion, the anterolateral lig-ament graft is secured with a 7 # 23emm biointerferencescrew. (IT, iliotibial.)

Table 1. Pearls and Pitfalls

PearlsA comprehensive understanding of the anatomy is essentialbecause ALL reconstruction is often performed in revisionsurgery settings and adhesions are often encountered.

The tibial attachment site of the ALL is at the midpoint betweenthe center of Gerdy’s tubercle and the anterior margin of thefibular head.

Applying a varus force to the knee will help identify the FCL,which can be used as a landmark to locate the femoral ALLattachment.

The ALL graft is passed deep to the superficial layer of the iliotibialband and superficial to the FCL.

PitfallsIf the femoral tunnel pin is not aimed anterior and proximal, it cancollide with an anterior cruciate ligament tunnel or damage thetrochlea.

Higher degrees of overconstraint are observed with ALL graftfixation at higher degrees of flexion.

It is essential to clear the attachment sites of all soft tissues to placethe tunnels at the proper location and aid with screw insertion.

Identification of the femoral attachment of the FCL should beperformed to avoid iatrogenic injury to it when reaming the ALLreconstruction tunnel.

ALL, anterolateral ligament; FCL, fibular collateral ligament.

e4 J. CHAHLA ET AL.

the tibia 13.1 mm distal to the lateral tibial plateau.11

On the lateral view, the femoral attachment was8.4 mm posterior and proximal to the lateral epi-condyle, whereas the tibial attachment was 19.0 mmposterior and superior to the center of the Gerdy tu-bercle. The biomechanical properties of the ALLshowed a mean maximum load of 175 N with a stiffnessof 20 N/mm. Importantly, the ALL was reproduciblyidentified in relation to surrounding anatomic andosseous landmarks to guide proper graft placementwhen performing reconstruction procedures, and thebiomechanical properties suggest most traditional soft-tissue grafts are of sufficient strength.Given this recent literature, we recommend our

approach for anatomic reconstruction of the ALL of theknee for residual anterolateral rotatory instability afterACL reconstruction or in patients with ACL deficiencyand a 3þ pivot shift on clinical examination. In mostcases, these indications would apply to those undergo-ing revision ACL reconstruction. However, future long-term studies with larger samples are needed to assessthe efficacy and patient-reported outcome measuresafter ALL reconstruction.

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