a Departamento de Ortopedia, Santa Casa de São Paulo, São Paulo, SP, Brasil
b Serviço de Ortopedia e Traumatologia, Hospital Israelita Albert Einstein, Universidade Federal de São Paulo (Unifesp), São Paulo, SP,Brasil
c Instituto de Ortopedia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brasil
d Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
Introduction
Some years ago, the technique most commonly used for recons-tructing the anterior cruciate ligament (ACL) using a graft fromthe flexor tendons was via the transtibial route, with the femoraltunnel high in the intercondylar area.1However, a recent studythat included 436 patients who underwent primary reconstructionof the ACL alone using an autologous graft showed that patientstreated by means of the transtibial technique had a significantlyhigher likelihood of requiring repeated surgery in the same knee,in comparison with those treated by means of an anteromedialroute.
There is an overall tendency toward reconstructions thatare anatomical in nature, since it is known that creation ofnon-anatomical tunnels may diminish joint mobility3and causeabnormal rotation of the knee during dynamic loading.
Given that many authors call their reconstructions anatomical,a precise definition of what this means is needed. A reconstruc-tion is anatomical when it seeks to functionally restore the ACLto its native dimensions, and to orientate the collagen and inser-tion sites, with the intention of reproducing the normal anatomy,restoring the kinematics and promoting long-term joint health
5For greater accuracy in creating anatomical femoral tunnels,drilling them by means of an accessory anteromedial portal hasbeen recommended.6The aim of this technical note was todescribe a technique for anatomical reconstruction of the ACL,with arthroscopic viewing through the anteromedial portal anddrilling of the femoral tunnel through the accessory anteromedialportal.
Surgical technique
We made an oblique incision of around 4 cm, in the proximal andmedial third of the lower leg, in order to diminish the likelihood ofinjury to the infrapatellar branch of the saphenous nerve.7Then,using an extractor, we removed the flexor tendons (gracilis andsemitendinosus).
An assistant at an auxiliary table removed the remains of themuscles from the tendons and sectioned their proximal end sothat they measured 18 cm. One of the ends of each of the tendonswas passed into the loop of the Endobutton®and was sutured toits other end over a length of 3 cm, using com Vicryl 1. Also usingVicryl 1, we sutured the 3 cm of the graft closest to the loop of theEndobutton®to each other and, in the same way, to the other tip,so as to make a quadruple graft of 9 cm in length.
Two Ethibond 5 threads were passed through the orifices of oneside of the Endobutton®and two Ethibond 2 threads through theorifices on the other side. The choice of Endobutton®loop size isdetermined by the length of the femoral tunnel, which is describedbelow.
The anterolateral and anteromedial portals for arthroscopywere constructed adjacent to the lateral and medial borders ofthe patellar ligament, respectively. The anteromedial portal wasopened at the level of the joint interline and the anterolateralportal was created slightly proximally to the joint interline.
Diagnostic arthroscopy was performed in order to treat anymeniscal and/or chondral lesions, if these were present. To viewthe medial face of the lateral femoral condyle, we moved the opti-cal device to the anteromedial portal.
The accessory anteromedial portal was established using anumber 18 needle, under direct viewing, inferiorly and mediallyto the standard anteromedial portal (Fig. 1). Its positioning is crit-ical for obtaining the correct pathway and determining the entrypoint for the femoral tunnel, so as to avoid injuring the surface ofthe medial femoral condyle and the medial meniscus, during thedrilling.
A bone pick, introduced through the accessory anteromedialportal, is used to demarcate the center of the femoral insertion ofthe ACL, at the junction of the insertions of its anteromedial andposterolateral bands, above the bifurcated crest.
A guidewire of 2 mm in diameter was introduced through theaccessory anteromedial portal and was placed at the location pre-viously marked out by the bone pick. It was driven into the boneof the lateral femoral condyle for a few millimeters, by means ofone or two hammer blows to its extra-articular end.
Following this, the guidewire was introduced by means of adrilling device, with the aim of crossing the lateral cortical boneof the lateral femoral condyle. For this drilling operation, the kneewas flexed at 110?, in order to protect the common fibular nerveand so that the femoral tunnel could have greater length
A cannulated drill bit of 5 mm in diameter was placed aroundthe guidewire and was used to create the femoral tunnel. The drillbit and guidewire were then removed and a measuring device wasused to determine the length of the femoral tunnel. The diameterof the femoral tunnel needed to be the same as that of the graft.
The guidewire was put back into the accessory anteromedialportal and was inserted into the femoral tunnel, until it had gonebeyond the cortical bone of the lateral femoral condyle. A drill bitof the same diameter as the graft should be used to increase thediameter of the preexisting tunnel, for a length that is 10 mm lessthan the total length of the tunnel, so that the Endobutton®couldbe upended.
The measurement of the Endobutton®loop should be no morethan the difference between the length of the femoral tunnel and15 mm, which is the minimum amount of soft-tissue graft inside
the bone tunnels for union to occur between the bone and thegraft.
To construct the tibial tunnel, we used a drilling guide thatwas appropriate for the ACL, adjusted to the mark of 55?. Thiswas introduced to the joint through the anteromedial portal, whilethe optical device was introduced through the anterolateral portal.The guide was placed on the tibia between the anteromedial andposterolateral bands, laterally to the medial intercondylar tuber-cle, in the same direction as the middle part of the anterior root ofthe lateral meniscus. The diameter of the drill bit for constructingthe tibial tunnel was also the same as the diameter of the graft.
A drilling guidewire with Vicryl 1 thread placed in one of itsorifices was passed through the accessory anteromedial portal, thefemoral tunnel and the lateral skin of the thigh, while a double endof Vicryl 1 was kept inside the joint.
Next, this end was pulled into the tibial tunnel with the aid ofa grasper or probe, and was brought to the external region of thelower leg.
The graft was lashed using Vicryl 1 and was passed throughthe tibial and femoral tunnels. Following this, the Endobutton was"upended", which provided femoral fixation. We applied manualtensioning to the threads of the tibial end of the graft, with theknee flexed at 20?,11and we fixed the graft in the tibial tunnelusing a metal interference screw or absorbable screw
Final comments
. In our opinion, viewing through the anteromedial portal pro-vides a clear view of the medial face of the lateral femoralcondyle, with the possibility of a clearer view of the femoralFig
insertion of the ACL, in comparison with the view obtainedthrough the anterolateral portal (Figs. 2 and 3).2. This technique does away with the need for guides, since theinsertion of the ACL is marked out by the surgeon, using a bonepick.3. There is no need for an additional incision in the distal andlateral thigh, as would occur with the outside-in technique.4. If the tunnels are constructed through the accessory antero-medial portal with due care, this does not cause any injury tothe cartilage of the medial femoral condyle, or to the medialmeniscus.5. With this type of viewing, it is also possible to make recon-structions using other grafts, such as double-band, selective(augmentation) and those that preserve the remaining liga-ment.
Conflicts of interest
The authors declare no conflicts of interest.
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