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Anterior Cruciate LigamentReconstruction: All-Inside ReconstructionJamie L. Lynch, MD,* and Kyle Anderson, MD†

Arthroscopic techniques to reconstruct the anterior cruciate ligament (ACL) are constantlyevolving. The treatment of ACL ruptures vary based on the patient, as well as, associatedinjury and even the surgeons preferred technique. Further attention to the ACL anatomyand attempts to improve the biologic environment for healing have lead to the creation ofthis all-inside ACL reconstruction. Furthermore, this method utilizes lesser-invasive, cor-tical-sparing sockets rather than full tunnels. An all-inside ACL reconstruction procedure isfully described below specifically detailing the required equipment, implants andtechnique.Oper Tech Sports Med 21:40-46 © 2013 Elsevier Inc. All rights reserved.

KEYWORDS: ACL, all-inside, graft-link, TightRope, cortical button

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In the past decade, orthopaedic sports medicine surgeonshave seen considerable modifications of the anterior cru-

ciate ligament (ACL) reconstruction. Generally, the goalshave been to create a lesser invasive more anatomic recon-struction while attempting to optimize the biological envi-ronment for healing. The purpose of this report is to presentan all-inside ACL reconstruction, called the graft-link tech-nique, which we believe encompasses all these principles.

The proposal of the all-inside ACL reconstruction is not anew concept. In 1995, Morgan et al sought to create an all-inside ACL reconstruction using bone-hamstring-bone com-posite graft fixed with metal interference screws.1,2 Stahelinnd Weiler described an all-inside technique in 1997.3 Theoal of their reconstruction method was developed to im-rove hamstring tendon fixation and facilitate early rehabil-

tation using biodegradable screws in both the femoral andibial tunnel, through AM portal and parapatellar incision,espectively.3 Nevertheless, these earlier techniques have

been considered technically demanding by some.4 More re-ently, Lubowitz described a simplified all-inside technique,sing a Dual RetroCutter, (Arthrex, Inc, Naples, FL), by wayf a transtibial method.4 This allowed for the creation of

sockets instead of full tunnels. Unfortunately, potential mal-

*Northeast Orthopaedics and Sports Medicine, LLP, San Antonio, TX.†Department of Orthopaedic Surgery, William Beaumont Hospital, Royal

Oak, MI.Address reprint requests to Jamie L. Lynch, MD, Northeast Orthopaedics

and Sports Medicine, 12709 Toepperwein, Suite 101, San Antonio, TX

c78233. E-mail: jlynch@neosm-sa.com

40 1060-1872/13/$-see front matter © 2013 Elsevier Inc. All rights reserved.http://dx.doi.org/10.1053/j.otsm.2012.11.001

positioning of one or both of the tunnels can occur with atranstibial approach.5,6

The attention to ACL anatomy and knee joint mechanicshas resulted in a better appreciation for the proper ACL tun-nel position. Purnell et al explained the transtibial error as amismatch graft position, specifically predisposing a graft topass from the posterolateral aspect of the tibial footprint tothe anteromedial (AM) aspect of the femoral footprint.7 Fur-hermore, femoral tunnels created in a transtibial mannerend to be relatively vertical and have less rotational stabili-y.8-11 Lee et al demonstrated a clinical increased pivot shift in

patients with more vertical grafts.12 Multiple authors havedemonstrated that nonanatomic femoral tunnel placement isthe most common technical error, leading to failure of ACLreconstruction.13,14

Creating an anatomic femoral tunnel can be done with thetraditional outside-in (OI) technique that requires dissectionover lateral–distal femur.15-17 As an alternative, low-profile or

exible reamer can be used through the AM portal with thenee in a hyperflexed position. There are, however, theoret-

cal and potential pitfalls described by numerous authorsased on cadaveric studies. This includes damage to the me-ial femoral condyle upon reamer entry into the joint, andamage to the posterior lateral femoral condyle, lateral gas-rocnemius, lateral collateral ligament, or common peronealerve with the guide pin.18,19 Additionally, posterior walllowout can occur at 90° of flexion with AM drilling of aingle bundle.20 Farrow and Parker demonstrated decreasedisk by drilling the AM bundle in hyperflexion of 130° spe-

ifically decreased distance to the LCL with respect to the PL

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ACL reconstruction 41

bundle in 130° of flexion.18 In general, it appears that lateralstructures are at less risk with higher knee flexion angles.18-21

However, the hyperflexed position of the knee associatedwith AM portal reaming has led to documented breakage ofthe guide pin.22

The present technique, however, revisits the OI concept,but allows for a small percutaneous incision, with no need formuscular dissection, and aids in direct visualization of thefemoral footprint through the AM portal without hyperflex-ion. As there is no need for hyperflexion, the knee is able torest at 90°, which is a very familiar position for the surgeonwhen visualizing the femoral footprint. By and large, thefemoral footprint is recreated near the center of the footprintmore reproducibly using a tibial tunnel–independent tech-nique, such as OI or AM portal method, but an OI approachresults in lower risk to the lateral femoral condyle than theAM portal technique.18,21 Lubowitz and Konicek also pointut that AM portal reaming of the femoral tunnel can result inhorter tunnels with respect to OI reaming.23

One hallmark of this technique is that sockets are createdrather than full tunnels. The result is that the extra-articularcortices are intact, which can decrease swelling, pain, andpossibly synovial fluid infiltration or flow through the graft–bone interface. The conceptual difference is that of “pottingthe graft” into a compact bony socket as opposed to pulling agraft through a full-length tunnel. This allows for more com-plete fill of the aperture and socket with graft collagen andeliminates the need for interference fixation, which can dis-place the graft to one portion of the aperture and can bedeleterious to healing by limiting healing interface area, aswell as affecting the biological milieu.

The described technique later in the text will focus primar-ily on an anatomic single-bundle ACL reconstruction usingautologous hamstring; however, with appropriate adjust-ments, it can also be used to complete a double-bundle ACLreconstruction. In addition, this cortical button techniquecan be used for autologous bone-patellar-tendon-bone(BPTB) graft. Most surgeons who use the TightRope (Arthrex,Inc, Naples, FL) with BPTB graft tend to use this fixation onsolely the femoral side. That being said, the principles of thisall-inside technique can be used for the femoral and tibialside of an autograft BPTB. One significant difference from astandard technique is the size of the graft must be smaller toensure that it does not bottom out during positioning andtensioning.

TechniquePatient PositioningThe patient is placed in the supine position with a post toassist with a valgus moment and a foot and thigh holder tohold the leg at 90° when needed. A tourniquet is applied, butrarely used.

Diagnositic Arthroscopy/Graft SelectionThe procedure is initiated with an examination using anes-

thesia. Many surgeons feel comfortable proceeding to graft

harvest based on these findings. If the examination or preop-erative data are not entirely clear, the diagnostic arthroscopycan be performed next to confirm the diagnosis before har-vesting tissue. This technique focuses on the use of autografthamstring. However, based on the individual patient, thechoice of graft can be altered to include soft-tissue allograft,BPTB autograft, or BPTB allograft.

Graft HarvestThe hamstring graft harvest can be completed through a tra-ditional approach over the pes tendons or through a mini-posterior approach as described by Prodromos et al.24 Thiswill allow for an exceptionally cosmetic harvest, as the inci-sion is not visible from anterior aspect of the knee. The graft-link technique uses a closed-loop graft where the tendon istripled or quadrupled, and can frequently allow for use of asingle hamstring tendon.25 The semitendinosus tendon isenerally more likely to be adequate for the single-tendononstruct. The surgeon must consider patient’s size, age, andctivity demands to best decide the required size for the graft.agnussen et al recently described the importance of graft

ize and risk for graft rupture.26 Secondary to this, additionaltudies, and the authors experience, we prefer our grafts to bemm or larger.27,28 However, we prefer them to be no larger

than 12 mm unless it is in the revision setting, in which case,a FlipCutter (Arthrex, Inc, Naples, FL) would not be used.

Graft Preparation and LinkageThe procedure uses a TightRope-Reverse Tensioning (Tight-Rope-RT, Arthrex, Inc, Naples, FL) for the femoral side andeither a TightRope-RT or a TightRope Attachable Button Sys-

Figure 1 TightRope-RT.

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42 J.L. Lynch and K. Anderson

tem for the tibial side. The TightRope is the second-genera-tion graft loop that is adjustable and assists in suspensoryfixation using a cortical button. This loop of suture is a knot-less locking mechanism that relies on multiple points of fric-tion to create self-reinforcing resistance to slippage undertension analogous to a finger-trap or seatbelt mechanism(Fig. 1).25

The adjustable graft loop decreases in length under ten-sioning of the free ends, or “tensioning strands.” The tension-ing strands pull the graft into the sockets by shortening theloop of suture through which the graft was passed. This elim-inates the need for precise length calculations and properloop length selection needed in the first-generation corticalbutton devices.25

However, graft length remains an important concern inthis technique in terms of its relationship with the overallconstruct length. Satisfactory estimations are 15-20 mm forthe femoral tunnel, 20-25 mm for the intra-articular seg-ment, and 25-30 mm for the tibial tunnel. The desired graftlength is 5-7 mm shorter than the total length of each of the

Figure 2 Set desired length of graft, considering femoral

Figure 3 Triple or quadruple the graft through the two TightRope-

Ts (Arthrex).

sockets plus the intra-articular distance, allowing for somemeasurement error.4 A major potential pitfall of this tech-nique is graft length mismatch. A short graft will not placeenough collagen tissue into the sockets, and a long graft willlead to bottoming out in the socket and inability to properlytension the graft. As a general guideline, a 20-mm femoralsocket and a 25-mm tibial socket plus approximately 25 mmof intra-articular distance will safely fit a 60- to 65-mm (afterpretensioning) graft.

Two TightRope-RTs (Arthrex) are placed on the graft prep-aration station such that their loops are set apart by the de-sired length of graft (Fig. 2). The graft is passed through theloops of the 2 TR-RTs, with as many passes as possible for thedesired length. This will establish the width of the graft (Fig.3). While maintaining significant tension on the graft ends,cerclage-type sutures are passed through and around eachend of the graft. Care must be taken to include each strand ofgraft in these sutures. Two cerclage sutures are passed at eachend of the graft (Fig. 4). We prefer to place these sutures at adistance from the end of the graft that matches the length ofthe socket—thus at 20 mm on the femoral end and 25 mm atthe tibial end. This is helpful during graft passage and ten-sioning and indicates how much tissue has been seated intoeach socket. Also, we prefer to start the cerclage sutures frominside so that the knot will be “buried” into the graft center,which decreases bulk of the graft to aid in graft passage, aswell as, minimize suture material at the graft–bone interface(Fig. 5).

The final closed-loop graft construct is then attached to aspring-loaded tensioning device to approximately 40 N. Wehave noted approximately 10% stress relaxation of the graftafter pretensioning. In addition, one must account for the fewmillimeters of the graft tissue within the loops of the TR, asthis will add to the ultimate length for the construct. Thisshould be considered when setting the initial distance of the2 TightRope-RTs (Arthrex). Thus, if a desired final graft

bial socket length and intra-articular distance.

Figure 4 Cerclage suture at both ends of the graft.

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ACL reconstruction 43

length is 60 mm, we set the initial distance at 50-53 mm.Also, single-tendon grafts may have slightly less stress relax-ation than double-tendon grafts.

The diameter of the graft should be determined while it ison the tensioning station. This can be done using a measuringblock with 0.5-mm increments. The authors determine thegraft length prior to creating the femoral and tibial sockets.

Femoral Socket PreparationThe joint is inspected, and débridement of the ACL remnantis performed while preserving the femoral and tibial foot-print. Notchplasty is avoided unless significant narrowing ofthe notch is observed. The femoral footprint is marked with aradio-frequency probe.

The authors prefer to create the ACL femoral socket via anOI approach using the FlipCutter (Arthrex), with ar-throscopic visualization from the AM portal with 90° of kneeflexion. This is preferred because this method creates a morecircular precise aperture, with complete freedom of position-ing, and there is no risk to the medial femoral condyle. Thisis as opposed to the more oblique tunnels and limited posi-tioning options of the transtibial reaming or the potentialdamage to the medial condyle, which can occur with medialportal reaming. After a soft-tissue notchplasty that specifi-cally maintains the fibers of the ACL, a radio-frequency probeis used to delineate the location of the lateral intercondylarand bifurcate ridges. Both the AM bundle and posterolateralbundle are found posterior to the lateral intercondylar ridge,whereas the bifurcate ridge divides the 2 bundles.29 Ideally,

Figure 5 Place the buried cerclage suture at a known distance fromhe end of the graft and use as an indicator of the amount of collagenithin the socket.

Figure 6 Arthroscope placed in the AM portal and the femoral guide

nters through the anterolateral portal.

the guide is placed directly on the bifurcate ridge as describedby Purnell and Larson.30 Unfortunately, these ridges are notlways visible.29,31 In this situation, different intraoperativeethods can be used to determine the correct starting point.

n addition, if a notchplasty is necessary and the anatomicttachment of the ACL is no longer evident, one should placehe guide pin for the FlipCutter (Arthrex) approximately0% from the deep cortex relative to the overall length of theemoral condyle with the knee at 90° of flexion. Also, notehat one should place the height to allow a 2-mm bone bridgerom the inferior articular cartilage with the knee flexed to0° (Fig. 6).32

The FlipCutter femoral guide (Arthrex) enters through theanterolateral portal, and the point is placed on the center offemoral footprint. The angle of the guide is set to 100°-110°.It has a unique graduated trochar guide sleeve with a nar-rowed tip that measures 7 mm in length. This allows foradvancement of the trochar into the bone of the lateral fem-oral cortex and the AM tibia for stability and accurate socketmeasurement. The FlipCutter trochar guide sleeve (Arthrex)should enter approximately 1 cm anterior to the posteriorborder of the iliotibial band and 2.5 cm proximal to thelateral femoral epicondyle.25 A number 11-blade is used toplace a small percutaneous incision through the skin and

Figure 7 Engage the reamer once it has entered the joint.

Figure 8 A passing wire or suture loop is retrieved from the femoral

socket.

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44 J.L. Lynch and K. Anderson

down through the IT band, and the guide is advanced 7 mminto bone. This is a built-in safety mechanism to provide a7-mm bridge of bone that is protected to prevent overream-ing through the cortex.

A FlipCutter (Arthrex) of the appropriate diameter isdrilled into the joint, and the guide is removed while theguide sleeve is then advanced 7-mm into the bone with amallet. The FlipCutter (Arthrex) is engaged and drilled ret-rograde (Fig. 7). For best visualization, an arthroscopicshaver can be used to clear bony debris as the reaming isperformed. The FlipCutter (Arthrex) is placed back into theknee, and the reamer is flipped back into its linear position tobe removed from the knee, while holding the guide sleevestable. Next, a coated suture (FiberStick, Arthrex) or passingwire is placed into the guide sleeve and into the joint to beused later as a passer for the sutures from the graft (Fig. 8).The looped suture is then removed from the joint via the ALportal and secured with a clamp on itself.

If traditional reaming is preferred, the femoral socket canbe created using AM portal with low-profile reamers or flex-ible reamers,33 and a Beath pin can be used to place a sutureloop within the femoral socket.

Tibial Socket PreparationAccurately placed tibial socket is important for proper globalalignment of an ACL reconstruction. Based on work byHarner et al, the tibial footprint is 120% of the femoral foot-print.34 Our previous teaching stressed using intra-articularuides for tunnel placement, specifically 7 mm anterior to theosterior cruciate ligament and at the posterior edge of thenterior horn of the lateral meniscus.35 Currently, the goal iso place the tunnel using the fibers of the tibial footprint.herefore, a shaver is used to gently débride the soft tissuesing the radio-frequency probe to mark the center of theootprint. The tibial socket is created with tibial FlipCutteribial guide (Arthrex) passed through the AM portal whileisualizing with the arthroscope in the AL portal (Figs. 9 and0). The guide angle will measure approximately 55°-60°. Inhe same manner as the femoral socket, a FlipCutter (Ar-hrex) will be used to create the tibial socket while using a

Figure 9 Place guide at the center of the tibial footprint.

haver to clear debris (Fig. 11). Once the socket is created, a

assing suture or wire is placed through the tibial guideleeve and into the joint.

Graft PassageBefore passing the graft, the surgeon must be certain the AMportal is large enough to pass the graft. To avoid creation of asoft-tissue bridge, we recommend usage of a “shoehorn” oropen-style cannula or a cannula large enough to pass thegraft. Also, it is essential that the passing sutures from thefemur and tibia do not become entangled. This is simplifiedby using a large combination retreiver/grasper, the tibial su-ture is retrieved in the sliding part of the retriever while thefemoral sutures are grasped in the grasper portion (Fig. 12).

It is often helpful to mark the intraosseous socket distanceon the loop of suture at the femoral end of the graft-linkconstruct. This is easily determined by reading the lasermarks on the FlipCutter (Arthrex) guide sleeve just as it exitsthe femoral guide. The distance is measured from the un-flipped button and marked on the suture loop, which con-tains the graft. The button will reach the cortex close to themoment the marking on the suture loop reaches the femoralaperture.

Figure 10 Pass drill through guide, then remove guide, and positionthe guide sleeve.

Figure 11 Engage FlipCutter (Arthrex).

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ACL reconstruction 45

Alternatively, the loop of suture, which contains the graft,can be lengthened and the arthroscope can be placed throughthe AM portal. This allows direct arthroscopic visualizationof the button and its sutures being passed up through thecortex of the femur while the graft is still outside the knee.Then, the scope can be repositioned in the anterolateral por-tal. The tensioning sutures are alternately pulled, and thegraft slowly positioned into the jont until it reaches the fem-oral aperture.

One pitfall of this all-inside technique can be inadvertentflipping of the button beyond the femoral cortex over the ITband or even the skin during advancement of the femoralTightRope-RT (Arthrex). The aforementioned measures canhelp avoid this pitfall. One must be certain that the buttondirectly opposed to the femur without soft-tissue interposi-tion or fixation will be compromised. Dissection of lateral softtissues may be required to assure that the button rests on thecortex, if it was pulled pass the iliotibial band. In initial cases,use of intraoperative fluoroscopy may be useful in confirmingposition of the button.

Once the femoral end of the graft is positioned at thefemoral aperture, the tibial button and its sutures are pulledinto the joint, through the tibial socket until the buttonpasses out of the AM cortex of the tibia. This step can also beobserved arthroscopically. Again, it is very important that thebutton be advanced along its long axis or it can becomelodged in soft tissue in the AM portal.

Graft TensioningAt this point, both ends of the graft should be at their respec-tive socket apertures. The femoral and tibial tensioning su-tures are tightened in an alternating manner so that each endof the graft is gradually advanced into its socket and neitherend is abruptly fully seated. If this occurs, the amount oftissue in the opposite socket may be compromised. Next, theknee is taken through a range of motion to ensure no need forfurther tensioning. The knee is brought out into full exten-

Figure 12 Tibial suture loop in the sliding portion and the femoralsuture loop in the graspers portion.

sion for final tensioning (Fig. 13). The femoral suture can be

cut at the skin level, or an arthroscopic suture cutter can beused to cut suture closer to the button. A square knot is tiedat the tibial button to help prevent inadvertent cutting ofsuture at the spliced segment. Refer to Table 1 for a list ofpearls for this procedure.

Postoperative CareA sterile dressing is applied, and the patient is fitted for abrace if deemed appropriate by the surgeon.

Postoperative RehabilitationThe postoperative rehabilitation is similar to other recon-structive techniques and is primarily dependent on surgeonpreference. The authors’ preference is to allow, but not force,motion as tolerated. Weight bearing is also advanced as tol-erated unless there is an associated meniscal repair or artic-ular cartilage restoration. We tend to use a postoperativehinged brace until there is good quadriceps activity and vol-untary contraction.

OutcomeAlthough anecdotal at this point, we have observed a substantialdecrease in pain and swelling in the early postoperative period(first 3 weeks). The acquisition of knee range of motion seems tobe easier and often faster than with autograft BPTB. At 2-3months, the reconstructions appear to be equivalent.

Figure 13 ACL reconstruction after final tensioning.

able 1 Pearls for the All-inside ACL Reconstruction

Mark interosseous length of the femoral socket on femoralloop sutures (distance from button)

Lengthen the TightRope loop on the femoral end to allowvisualization (via the AM portal) of passage of thefemoral button into the femoral socket and out of thecortex

Adjust the amount of graft in femoral tunnel and tibialtunnel by sequentially tensioning each side

Final tensioning should occur in full extension and aftercycling the knee through a full range of motion

Tie a square knot over the tibial button before cutting the

sutures to protect the spliced segment

46 J.L. Lynch and K. Anderson

ConclusionsThe authors have presented an all-inside ACL reconstructionthat allows for a more anatomic and a less invasive recon-struction that maintains the biological environment. TheFlipCutter (Arthrex) OI method results in small percutane-ous incisions to create sockets as opposed to tunnels. Second-generation ACL cortical suspensory fixation devices with ad-justable graft loop length (ACL TightRope-RT, Arthrex) placethe collagen of the graft in direct contact with the socketwithout need for interference fixation, which can alter rela-tive graft position and compromise healing interface. Withattention to anatomy and adherence to techniques describedearlier in the text, this all-inside technique is reproducibleand reliable.

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