SilbcAe

Protection of the Medial Femoral Condyle Articular CartilageDuring Drilling of the Femoral Tunnel Through the Accessory

Medial Portal in Anatomic Anterior Cruciate LigamentReconstruction

Ashraf Abdelkafy, M.D.

Abstract: Accurate positioning of the femoral tunnel in the native femoral anterior cruciateligament (ACL) footprint requires drilling through an accessory medial portal (AMP). The AMPis located far medial and at a low level. Despite the benefits of drilling through the AMP, it ispossible that the drill bit head will injure the articular cartilage of the medial femoral condyleas it slides along the guide pin to the femoral insertion of the ACL. Because more surgeons arenow performing anatomic ACL reconstructions and shifting from transtibial drilling towardtransportal drilling, the risk of this injury might be increasing, especially during the beginningof their learning curve. To avoid such injury, a bio-interference screw sheath is used. It isinserted through the AMP over the guide pin until it reaches near the medial wall of the lateralfemoral condyle. The drill bit is inserted over the guide pin and through the bio-interferencescrew sheath. Using the bio-interference screw sheath not only protects the articular cartilage ofthe medial femoral condyle but also protects the medial meniscus, posterior cruciate ligament,and skin of the AMP from injury because of the close proximity of the drill bit head to thesestructures during transportal drilling.

Sb

napmtrfd

ms

The cruciate ligaments have been recognizedsince ancient Egyptian times in the famous

mith Papyrus (333 BC). Now, and after understand-ng the exact insertion sites of the anterior cruciateigament (ACL), anatomic ACL reconstruction hasecome the treatment of choice whenever one isonsidering ACL reconstruction surgery. AnatomicCL reconstruction is gaining more and more pref-

rence among knee and sports medicine specialists.

From the Orthopedic Surgery Department, Faculty of Medicine,Suez Canal University, Ismailia, Egypt.

The author reports that he has no conflicts of interest in theauthorship and publication of this article.

Received March 31, 2012; accepted May 29, 2012.Address correspondence to Ashraf Abdelkafy, M.D., Orthopedic

Surgery Department, Faculty of Medicine, Suez Canal University,Circular Road 41522, Ismailia, Egypt. E-mail: ashrafkafy@hotmail.com

© 2012 by the Arthroscopy Association of North America

2212-6287/12213/$36.00http://dx.doi.org/10.1016/j.eats.2012.05.008

Arthroscopy Techniques, Vol 1, No 2 (D

urgical techniques involve single- and double-undle reconstructions.Accurate positioning of the femoral tunnel in the

ative femoral ACL footprint requires drilling throughn accessory medial portal (AMP). The AMP islaced far medial and at a low level (just above theedial meniscus).1-3 Drilling the femoral tunnel

hrough the AMP provides more flexibility for accu-ate positioning of the femoral tunnel in the nativeemoral ACL insertion site compared with transtibialrilling, which lacks this advantage.4-6

The far medial position of the AMP has 2 impor-tant advantages. The first is that it reaches the nativefemoral ACL insertion site, which is located at alower level on the medial wall of the lateral femoralcondyle, just posterior to the lateral intercondylarridge (resident ridge).1,2,7,8 In this area both antero-

edial (AM) and posterolateral (PL) bundles areeparated by the bifurcate ridge.7 In comparison,

transtibial drilling only allows drilling of the fem-

e149ecember), 2012: pp e149-e154

ttno[atdtslklaatstTm(a

ifbr

psv

t

e150 A. ABDELKAFY

oral tunnel at a higher position on the medial wall ofthe lateral femoral condyle away from the nativefemoral ACL footprint.7,9,10

The second advantage is that the drill bit becomescloser to the perpendicular axis3 of the medial wall ofhe lateral femoral condyle (transverse drill angle, i.e.,he angle at which the tunnel intersects with the lateralotch wall) and thus creates an appropriately sizedval aperture8 of the tunnel (in the anteroposteriorAP] axis) rather than a large oval aperture (in the APxis). A large oval aperture that results from drillinghrough a more central (not far medial) portal pro-uces an oversized mismatched femoral tunnel aper-ure in reference to the native femoral ACL footprintite size. In addition, the location of the AMP at aower level just above the medial meniscus and at anee flexion angle of about 100° allows one to estab-ish an appropriately sized proximodistal axis femoralperture rather than a large proximodistal axis femoralperture. A large proximodistal axis femoral aperturehat results from transtibial drilling produces an over-ized mismatched femoral tunnel aperture in referenceo the native femoral ACL footprint site size (Fig 1).his was confirmed in a recent study that showed aean femoral insertion site size of 8.9 mm for width

AP axis), 16.3 mm for length (proximodistal axis),nd 136.0 mm2 for area and, when a 9-mm drill bit

and a transverse drill angle of 40° were used, theaperture seemed to best match the native ACL foot-print when drilling was performed at a knee flexionangle of 102°.11

FIGURE 1. Articular cartilage injury to the medial femoral con-dyle caused by the drill bit head during drilling of the femoraltunnel through the AMP in anatomic ACL reconstruction. The

dguide pin is in the AMP, the arthroscope is in the central portal, andthe right knee is flexed 100°, with the patient in the supine position.

Despite the previously mentioned benefits of thelocation of the AMP, it still carries a risk for majorcomplications (Table 1). It is highly possible that thedrill bit head will injure the articular cartilage of themedial femoral condyle as it slides along the guidepin, traveling the distance from the AMP to the fem-oral insertion of the ACL (Fig 1). This is especiallytrue when the AMP is far medial, when the diameterof the drill bit head is large, when the intercondylarnotch is narrow, or when the AM tunnel is placed deepin the notch at the posterior end of the lateral femoralintercondylar wall.3,4,12

Because more and more surgeons are now perform-ing anatomic ACL reconstructions and shifting fromtranstibial drilling toward transportal drilling, the riskof injury to the articular cartilage of the medial fem-oral condyle might be increasing, especially duringthe beginning of their learning curve.3 In addition, thencidence of articular cartilage damage to the medialemoral condyle during anatomic double- or single-undle ACL reconstruction has not been accuratelyecorded yet.12

Damage to the medial femoral condyle articular car-tilage during transportal drilling of the femoral tunnel inanatomic ACL reconstruction is a serious and ominouscomplication that would be very disadvantageous to thepatient and might compromise the whole procedure12

(Fig 1). Thus protection of the articular cartilage of themedial femoral condyle during anatomic ACL recon-struction is of paramount importance.

Few reports have dealt with how to protect thearticular cartilage of the medial femoral condyle dur-ing transportal drilling of the femoral tunnel in ana-tomic ACL reconstruction. Transportal drilling carriesadditional risks of injury to the medial meniscus3 andosterior cruciate ligament (PCL) and violation of thekin of the AMP by the drill bit head because it passesery close to these structures.In this study, we present our technique for protec-

ion of the medial femoral condyle articular cartilage

TABLE 1. Main Risks of Drilling Femoral TunnelThrough AMP in Anatomic ACL Reconstruction

Injury to the articular cartilage of the medial femoral condyle bythe drill bit head

Injury to the medial meniscus by the drill bit headInjury of the PCL by the drill bit headViolation of the skin of the AMP by the drill bit head

uring transportal drilling.

I

i

rptF

T

pofl

da

attps

e151PROTECTION OF MEDIAL FEMORAL CONDYLE

SURGICAL TECHNIQUE

nstruments

The following standard knee arthroscopic and ACLnstruments are used: 4-mm 30° arthroscope, camera,

FIGURE 2. The guide pin is observed to be very close to therticular cartilage of the medial femoral condyle before drilling ofhe femoral tunnel through the AMP in anatomic ACL reconstruc-ion. The guide pin is in the AMP, the arthroscope is in the centralortal, and the right knee is flexed 100°, with the patient in theupine position.

FIGURE 3. Bio-interference screwsheath that is inserted through theAMP over the guide pin to protect thearticular cartilage of the medial femo-ral condyle from injury by the drill bithead in anatomic ACL reconstruction.

ecording system, shaver, pump, light source, monitor,owered drill, and ACL reconstruction set. In addi-ion, a bio-interference screw sheath (Arthrex, Naples,L) is used.

echnique

Under general or spinal anesthesia, the patient islaced in a supine position with the knee flexed at 90°r, alternatively, the leg is placed in a leg holder andexed freely at the extremity of the table.A 3-portal approach to the knee is used, with a stan-

ard anterolateral portal and central medial portal inddition to the AMP.1 The anterolateral portal is posi-

tioned above the joint line just lateral to the lateral borderof the patellar tendon. The central portal is created underarthroscopic visualization through the lateral portal witha spinal needle. The spinal needle should be in the centerportion of the notch in the coronal plane and in the lowerthird of the notch in the proximal-to-distal direction. Thecentral portal is positioned slightly above the joint lineand just medial to the medial border of the patellartendon.1 The AMP is designed to be far medial(approximately 2 cm medial to the medial border ofthe patellar tendon) and at a low level (superior tothe medial joint line and just above the medialmeniscus).1,2 Using all 3 portals as viewing andinstrumentation portals allows for complete visual-

e152 A. ABDELKAFY

ization of the entire ACL and its femoral and tibialinsertion sites.1

To harvest the semitendinosus and gracilis tendons tomake a quadrupled graft, a 1- to 2-inch oblique incisionis performed about 3 inches distal to the inferior pole ofthe patella and 2 inches medial to the tibial tuberosity.1

The femoral tunnel is drilled through the AMP underdirect visualization through the central medial portal.

The knee is flexed to 100°, and the guide pin isinserted through the AMP and drilled either throughthe center of the AM or PL bundle footprint in double-bundle ACL reconstruction or at a point located in thecenter between the footprint of the AM and PL bun-dles in single-bundle ACL reconstruction. At thispoint, the surgeon has to check the distance betweenthe guide pin and the articular cartilage of the medialfemoral condyle, and often he or she will find that thisdistance is too small12 (Fig 2).

To avoid injury to the medial femoral condyle ar-ticular cartilage by the head of the drill bit, we use abio-interference screw sheath that was originally de-signed for inserting a bio-interference screw in a fem-oral tunnel or a similar cannula. This bio-interferencescrew sheath is available in different sizes, from 7 to10 mm (Fig 3). The appropriate size is selected, pref-

erably measuring 1 mm larger than the size of the drill

bit that will be inserted through the sheath (Video 1).The bio-interference screw sheath is then insertedthrough the AMP over the guide pin until it reachesnear the medial wall of the lateral femoral condyle(Fig 4). The appropriately sized drill bit for the fem-oral tunnel is inserted over the guide pin and throughthe bio-interference screw sheath to drill the femoraltunnel (Fig 5).

The bio-interference screw sheath protects the articu-lar cartilage of the medial femoral condyle from injurythat might occur from advancing the drill bit of thefemoral tunnel over the drill guide close to the articularcartilage of the medial femoral condyle (Table 2). Thesheath has other important advantages including protec-tion of the medial meniscus, PCL, and skin of the AMPfrom injury by the drill bit head because of the closeproximity of the drill bit head to these structures duringtransportal drilling of the femoral tunnel in anatomicACL reconstructions (Table 2).

Between July 2009 and January 2012, 87 anatomicsingle-bundle ACL reconstructions were performedby the same surgeon (A.A.). In the beginning of thelearning curve, the previously described techniquewas not used in 45 patients (group A), whereas thistechnique was used in the subsequent 42 patients

FIGURE 4. A bio-interference screwsheath is inserted through theAMP over the guide pin until itreaches near the medial wall ofthe lateral femoral condyle, pro-tecting the articular cartilage ofthe medial femoral condyle, me-dial meniscus, PCL, and skin ofthe AMP in anatomic ACL re-construction. The guide pin andbio-interference screw sheath arein the AMP, the arthroscope is inthe central portal, and the rightknee is flexed 100°, with the pa-tient in the supine position.

(group B). Using this technique in group B resulted in

otaps

fA

doo

atftf

e153PROTECTION OF MEDIAL FEMORAL CONDYLE

0 injuries to the medial femoral condyle articularcartilage, medial meniscus, PCL, or skin of the AMP.In contrast, not using this technique in group A re-sulted in 3 injuries to the articular cartilage of themedial femoral condyle, 2 injuries to the medial me-niscus, and 8 injuries to the skin of the AMP.

DISCUSSION

Injury to the articular cartilage of the medial fem-ral condyle by the head of the drill bit during ana-omic ACL reconstruction is a serious complicationnd will compromise the functional result of the wholerocedure. Thus all efforts should be made to avoiduch a complication.

More and more surgeons are shifting toward per-orming anatomic ACL reconstructions through anMP after long periods of performing nonanatomic

FIGURE 5. The appropriately sizeddrill bit for the femoral tunnel isinserted over the guide pin andthrough the bio-interference screwsheath to drill the femoral tunnelthrough the AMP in anatomic ACLreconstruction. The guide pin, bio-interference screw sheath, and drillbit are in the AMP; the arthroscopeis in the central portal; and the rightknee is flexed 100°, with the patientin the supine position.

TABLE 2. Advantages of Drilling Femoral TunnelThrough Bio-Interference Screw Sheath Through AMP

Protection of articular cartilage of medial femoral condyle frominjury by drill bit head

Protection of medial meniscus from injury by drill bit headProtection of PCL from injury by drill bit head

Protection of skin of AMP from violation by drill bit head

ACL reconstructions using transtibial drilling.3 Earlyuring their learning curve, surgeons have to be awaref injury to the articular cartilage of the medial fem-ral condyle by the head of the drill bit.To reach the anatomic ACL femoral insertion site

nd to create a femoral aperture that closely matcheshe native ACL femoral aperture, drilling through thear medial AMP is mandatory. A recent study showedhat the mean femoral insertion site size was 8.9 mmor width, 16.3 mm for length, and 136.0 mm2 for

area.11 It also showed that the drill bit diameter, trans-verse drill angle, and knee flexion angle can all affectfemoral tunnel aperture morphology in medial portaldrilling during ACL reconstruction, and the authorsconcluded that when a 9-mm drill bit and a transversedrill angle of 40° were used, the aperture seemed tobest match the native ACL footprint when drilling wasperformed at a knee flexion angle of 102°; deviationsfrom this angle in either direction resulted in increas-ing tunnel area mismatch compared with the baselineaperture. The authors emphasized that the relationbetween drilling orientation and aperture morphologyis critical knowledge for surgeons performing ACLreconstruction.11

To my knowledge, few published articles have de-scribed techniques to avoid injury to the articular

cartilage of the medial femoral condyle by the head of

hpAfityflroksafr

saoacfpacd

atbt

1

1

1

1

1

e154 A. ABDELKAFY

the drill bit during transportal drilling. Pitfalls andsolutions for the use of the AM portal for the ACLfemoral socket were described by Lubowitz3 in 2009;e explained how, with the “composite” acorn reamerreloaded with a Beath pin and placed through theMP at a previously marked centrum of the ACL

emoral socket on the lateral wall of the femoralntercondylar notch and with the knee at 90° flexion,he flutes of the unconstrained reamer (Beath pin notet seated) may be placed around and past the medialemoral condylar cartilage, avoiding iatrogenic carti-age damage, which may occur when placing theeamer over a seated Beath pin (constrained reamer)r which may occur when placing the reamer afternee hyperflexion. Siebold et al12 in 2010 described aimilar technique called the guide pin maneuver tovoid damage to the articular cartilage of the medialemoral condyle during anatomic double-bundle ACLeconstruction.

Other authors studied the possibility of injury to theubchondral bone plate of the lateral femoral condylend the PL soft-tissue structures while drilling the fem-ral tunnel through the AMP at different knee flexionngles and in high and low AM portals.3,12-14 Theyoncluded that the low knee flexion angles when drillingemoral tunnels through the far AM portal might yieldotential risks of damage to the common peroneal nervend the posterior articular cartilage of the lateral femoralondyle and that the risks would be decreased at higheregrees of knee flexion.Advantages of the technique described in this study

re that it not only protects the articular cartilage ofhe medial femoral condyle from damage by the drillit head during transportal drilling but also protectshe medial meniscus12 and PCL and prevents violation

of the skin of the AMP. There are no potential riskswhen using the bio-interference screw sheath for pro-tection of the medial femoral condyle articular carti-lage during drilling of the femoral tunnel through theAMP in anatomic ACL reconstruction.

Limitations of this technique are few. The first limi-tation is the difficulty of inserting the bio-interferencescrew sheath in very narrow notches. The second isthe lack of availability of these special cannulae inevery arthroscopic ACL reconstruction setting.

In summary, using a bio-interference screw sheathor a similar cannula protects the articular cartilage ofthe medial femoral condyle from being injured by thedrill bit head when drilling the femoral tunnel throughthe far medial AMP in anatomic ACL reconstruction.Using this technique provides additional protection of

the medial meniscus, PCL, and skin of the AMP.

Using this technique routinely is beneficial for sur-geons during their early learning curve when they startshifting from transtibial drilling to transportal drillingin anatomic ACL reconstruction.

REFERENCES

1. Karlsson J, Irrgang JJ, van Eck CF, Samuelsson K, Mejia HA,Fu FH. Anatomic single- and double-bundle anterior cruciateligament reconstruction, part 2: Clinical application of surgicaltechnique. Am J Sports Med 2011;39:2016-2026.

2. Araujo PH, van Eck CF, Macalena JA, Fu FH. Advances in thethree-portal technique for anatomical single- or double-bundleACL reconstruction. Knee Surg Sports Traumatol Arthrosc2011;19:1239-1242.

3. Lubowitz JH. Anteromedial portal technique for the anteriorcruciate ligament femoral socket: Pitfalls and solutions. Ar-throscopy 2009;25:95-101.

4. Harner CD, Honkamp NJ, Ranawat AS. Anteromedial portaltechnique for creating the anterior cruciate ligament femoraltunnel. Arthroscopy 2008;24:113-115.

5. Tompkins M, Milewski MD, Brockmeier SF, Gaskin CM,Hart JM, Miller MD. Anatomic femoral tunnel drilling inanterior cruciate ligament reconstruction: Use of an accessorymedial portal versus traditional transtibial drilling. Am J SportsMed 2012;40:1313-1321.

6. Zeman P, Nepraš P, Matejka J, Koudela K Jr. Anatomicaldouble-bundle anterior cruciate ligament reconstruction—Transtibial versus anteromedial reaming of femoral tunnels.Acta Chir Orthop Traumatol Cech 2012;79:41-47 (in Czech).

7. Bedi A, Raphael B, Maderazo A, Pavlov H, Williams RJ III.Transtibial versus anteromedial portal drilling for anterior cru-ciate ligament reconstruction: A cadaveric study of femoraltunnel length and obliquity. Arthroscopy 2010;26:342-350.

8. Yasuda K, van Eck CF, Hoshino Y, Fu FH, Tashman S.Anatomic single- and double-bundle anterior cruciate ligamentreconstruction, part 1: Basic science. Am J Sports Med 2011;39:1789-1799.

9. Kopf S, Forsythe B, Wong AK, Tashman S, Irrgang JJ, Fu FH.Transtibial ACL reconstruction technique fails to position drilltunnels anatomically in vivo 3D CT study. Knee Surg SportsTraumatol Arthrosc. 2011 Dec 31. [Epub ahead of print.]

0. Forsythe B, Kopf S, Wong AK, et al. The location of femoraland tibial tunnels in anatomic double-bundle anterior cruciateligament reconstruction analyzed by three-dimensional com-puted tomography models. J Bone Joint Surg Am 2010;92:1418-1426.

1. Hensler D, Working ZM, Illingworth KD, Thorhauer ED,Tashman S, Fu FH. Medial portal drilling: Effects on thefemoral tunnel aperture morphology during anterior cruciateligament reconstruction. J Bone Joint Surg Am 2011;16:2063-2071.

2. Siebold R, Benetos IS, Sartory N, He Z, Hariri N, Pässler HH.How to avoid the risk of intraoperative cartilage damage inanatomic four tunnel double bundle anterior cruciate ligamentreconstruction. Knee Surg Sports Traumatol Arthrosc 2010;18:64-67.

3. Zantop T, Haase AK, Fu FH, Petersen W. Potential risk ofcartilage damage in double bundle ACL reconstruction: Im-pact of knee flexion angle and portal location on the femoralPL bundle tunnel. Arch Orthop Trauma Surg 2008;128:509-513.

4. Nakamura M, Deie M, Shibuya H, et al. Potential risks of

femoral tunnel drilling through the far anteromedial portal: Acadaveric study. Arthroscopy 2009;25:481-487.