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Anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons, bone patellar tendon, or quadriceps tendon–graft with press-fit fixation without hardware
Orthop Clin N Am 34 (2003) 49 – 64
Anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons, bone patellar tendon, or quadriceps tendon–graft with press-fit fixation without hardware A new and innovative procedure Hans H. Paessler, MD*, Dimitrios S. Mastrokalos, MD Center for Knee and Foot Surgery and Sport Injuries, ATOS—Clinic Heidelberg, Bismarckstrasse 9-15, Heidelberg 69115, Germany
The importance attached to the anterior cruciate ligament (ACL) as a knee stabilizer is reflected in the many techniques that have been developed for the surgical reconstruction of the ACL-deficient knee. There are three main reasons for this interest in the ACL: (1) ACL injuries are frequently encountered and may occur on an ‘‘epidemic’’ scale (downhill skiing); (2) ACL disruption results, not only in anterior instability, but also in meniscal lesions and in an increased rate of degenerative changes [1]; and (3) primary repair may not produce the desired outcome because the injured ACL has a notoriously poor healing potential, which has been attributed to the ACL cells’ inherently poor regeneration capacity, to the disruption of the ligament’s blood and nutritional supply, and to the complex geometry of the ACL [2 – 4].
Bone—patellar tendon Currently, the most frequently used autograft material for ACL reconstruction is the middle one third of the patellar tendon [5 – 7]; the bone blocks at either end are fixed with interference screws. Prob-
* Corresponding author. E-mail address: [email protected] (H.H. Paessler).
lems such as patellofemoral pain [8,9], patellar fractures [10 – 12], bone resorption around the implants [13], tunnel widening—especially of the tibial tunnel [14,15], and difficulties with hardware removal at revision surgery have, however, been reported. Graft harvesting The technique of bone-patellar tendon-bone (BPTB) autografts involves harvesting of the patellar tendon with two bone blocks, one from the tibial tubercle and one from the patella. The rationale advanced for this technique is that each bone block is inserted into a tunnel, usually secured with interference screws, allowing bone-to-bone healing, and, therefore, early aggressive rehabilitation. Patellofemoral pain, however, is a common and sometimes serious problem following ACL reconstruction with BPTB grafts. This complication has been reported in 40% to 60% of cases [16]. In a number of patients, secondary surgery for the retrieval of troublesome fixation hardware has been found to be required [17,18]. Patellofemoral pain and donor site morbidity appear to be unaffected by whether the patellar tendon defect is closed or left open [19]. In a small number of cases, patellar bone defects may cause patellar fractures at a subsequent stage, when the patella is exposed to stress during reha-
0030-5898/03/$ – see front matter D 2003, Elsevier Science (USA). All rights reserved. doi:10.1016/S0030-5898(02)00070-6
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bilitation [10,12]. Primary bone grafting of the patella has been proposed as a means of preventing such fractures [20]; its use does not appear, however, to have resulted in a significant reduction in the rate of this complication. Harvesting the tendon with a tibial tubercle bone block, but leaving the patella itself intact, reduces the time required for surgery, and it protects the patella from fracture. During follow-up, we have also observed that donor site morbidity is less following BPT compared with BPTB graft procedures, probably because the patellar bone remains intact. Another source of single-bone-block tendon grafts is the quadriceps tendon: Staeubli [21,22] reported excellent results with quadriceps tendon procedures and also found less morbidity compared with BPTB. Preparation of the bone tunnels Traditional methods use drilling for the creation of bone tunnels. Drilling is known to cause circumferential bone necrosis as a result of thermal damage [12,23]. This may contribute to delayed graft incorporation, and to eventual reconstructive failure [24]. With our method, drill bits are used exclusively for the perforation of the cortex. The cancellous bone of the femoral tunnel is removed using special bone cutting (harvester) tubes, whereas compaction drilling is used for tibial tunnel creation. This technique has three important advantages: (1) no drilling heat is produced; (2) the tunnel walls are smoother; and (3) a core of cancellous bone is produced for use in grafting the tibial donor site defect and for plugging the dead space in the tibial tunnel. Prevention of windshield-wiper and synovial-bathing effects Because the patellar tendon graft is flat, the crosssectional area of the tendinous graft portion is smaller than that of the bone block. As a result, the tendinous portion located at the articular entrance of the tibia bone tunnel does not completely fill the tunnel lumen. This allows transverse motion of the tendinous portion of the graft within the tunnel, a phenomenon known as the windshield-wiper effect [15]. This to-and-fro movement of the graft within the tunnel is an important cause of tunnel enlargement after ACL reconstruction [13]. Also, the dead space between the flat graft and the bone tunnel allows the ingress of synovial fluid (synovial-bathing effect), which exposes the bone to cytokines that may stimulate osteoclastic activity and bone resorption [25]. These phenomena may also be involved in tunnel enlargement.
Three Krackow sutures and one baseball stitch are placed into the distal 3 cm of the tendon. In this way, the discrepancy in diameter between the tibial tunnel and the bone-free end of the graft is abolished, and the graft should ‘‘plug and seal’’ the tunnel to prevent synovial fluid ingress. This should encourage more rapid graft incorporation. Also, the risk of tunnel widening should be minimized by the prevention of the windshield-wiper effect. Graft fixation Numerous methods for ACL graft fixation to bone have been proposed. Fixation techniques include staples, sutures tied to posts, interference screws, press-fit, and sutures tied over buttons. The goal of all these methods is to achieve firm fixation and to enable the graft to resist in vivo forces until it has been fully incorporated. Kurosaka [26] reported that, of the different fixation methods for patellar tendon grafts tested, the strongest fixation (475 N maximum load) was provided by the 9-mm interference screw. Steiner [27] found that the fixation strength of hamstring grafts secured with soft tissue washers was comparable to that of BPTB grafts secured with screws; the hamstring grafts, however, had less stiffness. The mean tensile strength provided by the locking-loop tendon-ligament suture developed by Krackow was found to be 223 N; using two locking-loop sutures, the strength was 392 N [28]. It was estimated by Noyes et al that the ACL encounters normal daily forces of between 20 N and 440 N [29]. Because patients are advised to reduce their activity during the postoperative period, the fixation techniques mentioned above may be assumed to protect the construct until the graft-bone interface has healed. Numerous clinical studies involving various fixation methods have reported high rates of excellent or good results [27,30 – 33]. Our method of graft fixation is a combination of a press-fit technique, on the femoral side; and press-fit plus sutures (locking-loop technique) tied over a 10-mm bone bridge as a post, on the tibial side. The femoral press-fit technique was first described by Hertel [34]. In a biomechanical study, Brown [35] compared press-fit fixation of the femoral bone plug (failure strength, 350 N) with fixation by means of interference screws, Endo-Button CLTM (Acufex, Smith and Nephew, MA), and MitekTM (Ethicon, Somerville, NJ) anchors. No statistically significant difference was found between these methods. Clinically, the press-fit technique has been shown to be safe. In a short follow-up (2 – 3 years), Boszotta [36] showed satisfactory results with the press-fit tech-
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nique. In a 10-year follow-up study, Hertel [31] reported excellent subjective and objective (eg, stability) results. It also has been demonstrated that the quadriceps tendon with one bone plug, which is fixed in the femoral tunnel, is an excellent graft with clinical outcome similar to patellar tendon. Krackow [28] found their suture technique to provide satisfactory soft-tissue fixation in ligament reconstruction surgery. Based on their findings, we have adopted a triple locking-loop stitch for tibial fixation, with the ends tied over a bone bridge. Shelbourne [37] reported a 94% success rate with sutures tied over buttons for the tibial fixation of BPTB grafts. Boszotta et al [38], in an experimental study, compared four different methods of tibial fixation (titanium interference screw, titanium staple, suture fixation over a bone bridge, and suture fixation over a bone bridge, with refilling of the tibial tunnel and the bone blocks gained from the preparation of femoral and tibial tunnel). He found that tibial fixation of the graft with sutures over a bone bridge with refilling of the tibial tunnel with bone blocks showed the highest failure load (758 N) (IF screw: 572N, staple: 608.4, sutures only: 304.5N). Ease of revision surgery Revision surgery after a failed ACL reconstruction is a challenging and difficult procedure. Among the many problems to be addressed is that of hardware removal. Removal of the fixation hardware may be very difficult—for example, if the screws have been overgrown by bone. Our ‘‘no hardware’’ technique obviates these problems and facilitates revision surgery.
Semitendinosus—gracilis Over the past few years, there has been increasing interest in the use of the semitendinosus tendon for ACL reconstruction because of the comparatively low postoperative morbidity. Pinczewski et al (2002) [39] recently reported 5-year results in a prospective study, comparing patellar tendon and 4-strand hamstring tendon graft for ACL reconstruction. Patellar tendon grafts appeared tighter clinically, and with lower KT 1000 measurements, up to 3 years postoperatively, compared with hamstring grafts, but thereafter the results were similar. Anderson et al [40] confirmed the 3-year results of Pinczewski et al [39] according to objective stability with a slight superiority of the bone patella tendon graft. The subjective results and the results from muscle strength testing
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were better in the hamstrings group. They found a worrying trend toward osteoarthritis developing in the patellar tendon group. Kneeling pain also remained a persistent problem in the patellar tendon group. According to their results, the passage of time seems to favor the hamstring group over the patellar tendon group. In many of the prospective studies published to date, however, the stability achieved with hamstring tendons was found to be inferior to that obtained with the patellar tendon [30,32,33,41]. In most of these studies, fixation away from the point of insertion with the Endo-Button technique was used. Hoeher et al [13] demonstrated in their experimental studies creep near the tendon-tape-transition with a give in of the tendon construct and a permanent elongation of 3.8+/ 0.8 mm. This so-called bungee effect may result in tunnel enlargement and graft failure. Recently, fixation techniques using metal or bioresorbable interference srews have been popularized. Van der Reis et al [42], however, compared different hamstring fixation devices under cyclic loading (Endo-Button CL, LinX-HT (Ethicon, Somerville, NJ), Trans-Fix (Arthrex, Naples, FL), Bioscrew (Arthrex, Naples, FL)). They found that all devices performed well under cyclic loading except the Bioscrew. Clatworthy et al [14] prospectively studied the effect of four different fixation techniques (Bioabsorbable IFSTM [Arthrex, Naples, FL], RCI-IFSTM [Smith and Nephew, MA], Bone MulchTM Screws/ Staples [Arthrotek, Warsaw, IN], Endo-Button/Staples [Arthrex, Naples, FL]) on tunnel widening in hamstring ACL reconstruction. As with Van der Reis et al [42], they showed that use of the bioscrew resulted in larger tunnel dilation. Our technique uses press-fit graft fixation of hamstring grafts close to the anatomic ACL insertion, thus eliminating both the bungee and windshield wiper effects and the need for any implant. The semitendinosus tendon and the gracilis tendons both are tied together by a simple knot, which is secured by nonabsorbable sutures. A bottle neck-like tunnel is created on the femoral side, in which the knot of the tendon loop is firmly secured just proximal to the cortex of the notch wall at the anatomic insertion.
Biomechanical testing In cooperation with A. Weiler, MD and F. Kandziora, MD (unpublished data, 1999) biomechanical pull-out tests on pig knees have shown that under cyclic loading (100 x 300 N, 100 x 400 N, 100 x 500 N, 100 x 600 N, and 100 x 700 N)
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this technique was demonstrated to be twofold stronger than the ‘‘Gold Standard’’ BTB fixed with interference screws. In this article, two new techniques for ACL reconstruction with press-fit fixation are presented: (1) a BPT without a bone block from the patella or a quadriceps tendon graft with a bone block, and (2) a semitendinosus—gracilis graft. These methods overcome many of the complications mentioned above, or the rate of these complications is low.
Surgical technique Setup We use the same setup for all three grafts. The operation may be performed under either general or regional anesthesia. A pneumatic tourniquet is placed on the proximal thigh of the injured leg, but generally not inflated. An infusion pump allows the procedure to be performed without tourniquet control. The operating table is angled at knee level, to allow the injured leg to hang over the edge of the table. A lateral post is used for applying a valgus force. The opposite leg is abducted and positioned straight. A VenaFlowTM system (Aircast, Summit, NJ), which provides pneumatic compression to the lower leg for the prevention of deep vein thrombosis (DVT), is applied to the uninvolved leg. The device is intermittently inflated and deflated during the operation. Standard arthroscopic equipment consists of a 30° arthroscope, arthroscopic cannulas, cannulated drills, and a motorized burr. Under anesthesia, the knee is examined meticulously, using the full range of stability tests. In addition, knee laxity measurement is performed using a KT-1000TM arthrometer (MEDmetric, San Diego, CA). Before skin incision, a first-generation cephalosporin is given intravenously. At the same time, 0.375 mL/kg of 0.25% bupivacaine hydrochloride with adrenaline 1 in 100,000 is instilled into the knee joint, into the area of skin incision for graft harvesting and into the portals. This provides hemostasis and reduces postoperative pain.
tuberosity might be reasons of donor site morbidity. Therefore, we prefer a subcutaneous graft-harvesting technique with a double incision that avoids injury to the infrapatellar nerve. With the knee flexed to 90°, a 25-mm vertical incision is made just above the tibial tubercle. The medial and lateral borders of the patellar tendon are identified easily by retracting the skin in either direction. The tendon sheath is divided lengthwise and dissected up to the lower pole of the patella. We prefer the medial or lateral third of the patellar tendon although some authors [44] report good results with the medial third of the patellar tendon. Matarazzo et al [45] showed that harvesting of either the medial or lateral third of the patellar tendon results in significantly less donor site morbidity than the central third. The medial or lateral third of the patella, furthermore, are longer than the central one. The medial or lateral one third of the patellar tendon is sharply incised with parallel incisions, using a standard Smillie meniscus knife (Sklar, West Chester, PA) to create an 11-mm-wide graft. The tibial 25to 30-mm bone block with a diameter of 9 to 10 mm is harvested using a narrow oscillating saw. Once the bone block has been harvested, the knee is placed in full extension. A second 20-mm vertical incision subsequently is made along the apex of the patella. The prepatellar bursa and the paratendon are incised down to the aponeurosis. A sharp towel clamp is pushed under the skin and the paratenon from the proximal incision and out through the distal incision. The distal bone block is grasped with the clamp and pulled in the proximal direction under the paratenon and out through the proximal incision (Fig. 1). The
Bone—patellar tendon graft Graft harvesting Kartus et al [43] recommend avoidance of intraoperative injury of the infrapatellar nerve because this fact and the harvesting of one block from the tibial
Fig. 1. Harvesting of patellar tendon graft using two small horizontal incisions.
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graft is subperiosteally stripped off the patella, over a distance of 20 to 25 mm (Fig. 2). Fulkerson et al [46] described a simple technique of harvesting a quadriceps graft. The quadriceps tendon is harvested with a bone plug from the patella. Graft preparation The bone block is trimmed to form a cylindrical plug, usually 9-10 mm in diameter. Next, a drill hole is made in the bone plug, and a holding suture (Mersilene No 3) is passed through it. A baseball stitch (Vicryl #1) and three Krackow locking-loop stitches (Ethibond No 2) are placed in the distal 3 cm of the bone-free end of the tendon (Fig. 3). The diameter is checked by passing the tendon end through cylindrical sizers that are supplied in halfmillimeter increments.
Fig. 3. The free end of the graft is armed with three Krackow sutures and distal baseball stitch. The bone block is trimmed cylindrically.
Under arthroscopic visualization, any ACL remnants are removed with a shaver, and notchplasty is performed using a motorized burr to enlarge the notch roof. Next, the femoral tunnel is prepared. Our positioning of the femoral tunnel derives from the experimental findings of Hefzy [47] regarding the most isometric attachment of the ACL. It is widely accepted that an ACL graft should be positioned at the original anatomic position at 10’clock [48 – 52]. In a recent prospective in vivo study (publication in process) we evaluated whether a guide pin for a femoral tunnel could be positioned through the tibial tunnel into the center of the anatomic ACL attachment. The study confirms the results of a recent
cadaveric study by Arnold et al [53] that transtibial femoral-tunnel drilling does not reach the anatomic site of the ACL insertion, even with larger tibial tunnels (for hamstring grafts up to 8.5 mm). This may explain why in many studies in which hamstring grafts and transtibial tunnel drilling were used, an increase of laxity compared with patellar tendon grafts is observed. Therefore, we prefer drilling of the femoral tunnel through the anteromedial portal. A femoral over-the-top drill guide, with an offset of 6 mm, is used for accurate placement of a 2-mm K-wire at 10 o’clock (right knee) or 2 o’clock (left knee) under fluoroscopic control. With the knee flexed to 120 to 130 degrees, the K-wire is drilled through the femoral condyle until it protrudes through the skin of the thigh (Fig. 4). A hard copy of this fluoroscopic image is made and added to the patient’s chart to complement the set of arthroscopic images. Using atraumatic cannulated reamers, only the medial cortex is over-reamed to the measured diameter of the cylindrical bone plug of the graft (Fig. 5). The cancellous bone is removed using a harvester tube 1 mm
Fig. 2. The graft is subperiosteally stripped off the patella, over a distance of 20 – 25 mm.
Fig. 4. Placing of a 5-mm offset drill guide in the over-thetop position.
Femoral tunnel
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Fig. 5. With use of atraumatic cannulated reamers, only the medial cortex is over-reamed to the measured diameter of the cylindrical bone plug of the graft.
smaller in diameter than the bone block itself; the harvested plug is preserved for subsequent implantation into the tibial tunnel (Fig. 6). A K-wire with an eyelet is introduced into the femoral tunnel and drilled through the anterolateral cortex for the passage of a guide suture, which will be used to pull the suture attached to the bone plug. Tibial tunnel The knee is flexed to 90°, and preparation of the tibial tunnel is begun. A recent study [54] demonstrated that the inner rim of the anterior horn of the lateral meniscus corresponds well with the midpoint of the ACL footprint. Using the tibial drill guide, a 2.5-mm drill bit is advanced through the skin incision, medial to the tubercle and into the joint. At this stage, in order to guard against later graft impingement, a special impingement probe is intro-
Fig. 7. A special impingement probe is introduced through the anteromedial portal and placed on the 2.5-mm K-wire.
duced through the anteromedial portal and placed on the drill bit. When the knee is taken into full extension, there should be a clearance of about 3 mm between the notch roof and the probe (Fig. 7). After confirmation of correct placement of the 2.5-mm drill bit, the tibial cortex is pierced with a 6.5-mm or a 7-mm reamer (depending on the diameter of the patellar tendon). This is followed by compaction drilling with a dilator of the same diameter, to compact the cancellous bone surrounding the tibial tunnel. The cortex of the tibial plateau is drilled under arthroscopic visualization (Fig. 8).
Fig. 6. Bone harvesting tube is tapped 30 mm deep into the femur.
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through the tibial tunnel with a guide suture. Isometry is tested. Over the full range of motion, the movement of the graft should be less than 2 mm; in hyperextension the substitute ACL should be tense. In hyperextension, a check is also made to ensure that there is sufficient clearance between the graft and the anterior border of the notch (impingement test). Using a 4.5-mm drill bit, a drill hole is made 1 cm distal to the exit of the tibial tunnel. With a curved clamp, a bone tunnel is created in the cancellous bone, and a cortical bone bridge is fashioned, over which the sutures will be tied (Fig. 11). With the knee in full extension, half of the sutures attached to the tendon end are passed under the bridge and tied to the remaining sutures, which have been passed over the bridge (Fig. 12). A check is made to ensure that the range of motion is full, and a Lachman test is performed. Finally, one half of the harvested bone core is packed into the tibial tunnel (Fig. 13), and the other half is placed in the tibial tubercle donor site. The patellar tendon deficit is closed by juxtaposing the edges of the outermost layer with a continous Vicryl (Ethicon, Somerville, NJ) suture. Another Vicryl suture is used to close the retinaculum and Fig. 8. The cortex of the tibial plateau is drilled under arthroscopic visualization.
Any tissue remnants anterior to the tunnel mouth are removed to prevent the formation of a cyclops syndrome lesion postoperatively. Graft placement for both patellar and quadriceps tendon The suture attached to the bone plug of the graft is pulled through the femoral drill hole by the guide suture. Firm traction on the graft sutures will make the graft slide into the joint through the anteromedial portal, and the bone plug will enter the femoral tunnel. With the knee flexed to 120°, a special impactor with two spikes (Fig. 9) is used to drive the cylindrical plug into the femoral tunnel, in such a way as to make the bone plug cortex face posteriorly in the tunnel, to obtain posterior alignment of the collagen fibers of the graft. The angle between the bone plug cortex and the long axis of the femur should be 25° (Fig. 10). The free end of the graft is twisted to make the graft fibers facing the posterior cruciate ligament (PCL) lie anteriorly to produce an anteromedial and a posteromedial bundle. Then, the holding sutures on the free end of the graft are pulled
Fig. 9. A special impactor with two spikes used for impaction the femoral bone block.
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Fig. 10. With the special impactor, the bone block of the graft is tapped into the femoral socket.
the tendon sheath. Finally, 0.300 mL/kg of 0.25% bupivacaine hydrochloride with adrenaline 1 in 100,000, and 1 ampoule of morphine (10 mg) are injected intra-articularly. A thin compression dressing is applied over the wound, and a Cryo/CuffR knee compression system (Aircast Inc., Summit, NJ), which has been shown to provide control of swelling and bleeding postoperatively [55], is placed around the knee (Fig. 14). In addition, the operated leg is also fitted with a VenaFlow system,while the patient is in the recovery room.
Semitendinosus—gracilis graft Graft harvesting With the knee flexed to 90°, a 2-cm incision is used 3 cm medial and distal to the tibial tuberosity,
Fig. 11. Tibial fixation: with a 4.5-drill bit, a drill hole is created 1-cm distal to the tibial tunnel exit and a cortical bone bridge is fashioned using a curved clamp over which the sutures will be tied.
Fig. 12. The graft sutures are tied over the bone bridge.
parallel to the lines of the skin, to avoid damage to the inferior branch of the saphenous nerve, and for cosmesis (Fig. 15). The bursa of the pes is incised and split proximally. Both the tendons are visualized and mobilized. First the gracilis tendon is grasped using a curved clamp. Maximal traction is applied, which releases the ‘‘web-like’’ fascia slips. The gracilis tendon is inserted into an open stripper (Richard Wolf, Knittlingen, Germany), which is advanced proximally about 25 cm (Fig. 16). At this point, the tendon is cut by closing the stripper. The tendon remains attached to the periosteum, and the semitendinosus is harvested in a similar manner. Finally, the tendons are stripped off the tibia with their periosteal insertion (Fig. 17). On the workstation, the tendons are gently dissected free of muscle tissue. The ends of each tendon are tied together in a simple knot (Fig. 18). The knots are maximally tightened under cyclic manual load.
Fig. 13. The cancellous bone cores are introduced and tapped into the tibial tunnel.
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Fig. 14. The Cryo-CuffTM knee compression system (Aircast Inc., Summit, NJ).
With the help of a Merslilene (Ethicon, Somerville, NJ) tape, the loops are pulled one after the other through a measuring template in 0.5-mm site increments in order to find the smallest diameter of both loops (Fig. 19). To distinguish between the loops, different-colored Mersilene tapes are used. The diameter of the knots should be 4 mm more than the diameter of the loops. The grafts are mounted to the workstation. The knots are secured with 4 diverging U-shaped Ethibond No 2 (Ethicon, Somerville, NJ) sutures (Fig. 20). The loop length after knotting is equal to the cortical thickness, about 5 to 6mm, plus the intraarticular graft length, about 30 mm,and the length of the tibial tunnel at 45°, about 40 mm. This totals 75 mm for the semitendinosus tendon, and 85 mm for the gracilis tendon. The gracilis loop must be longer because the knot of the gracilis tendon will be proximal to the semitendinosus knot. The intra-articular portions of the graft are marked.
now moved to the joint for positioning of the tip of the Kirschner wire. The ideal position of the tip is on an imaginary line continuing from the posterior cortex of the distal femur, approximately 5 to 7 mm inferior to Blumenstaat’s line. The knee is then flexed to 125°. The K-wire is inserted into the cortex to a depth of approximately 5 mm. The drill guide is removed, and the femoralK-wire overdrilled with a cannulated reamer, matching the diameter of the two loops. If harvesting of cancellous bone graft is desired, then the reamer is advanced cautiously until it reaches the cancellous bone at a depth of 5 to 7 mm; it is then withdrawn. The appropriate harvester tube (Richard Wolf, Knittlingen, Germany) is selected from the range of tubes provided in 0.5 mm increments. The harvester tube is inserted and advanced beyond the lateral cortex. In young subjects, with a very hard cortex, the tube should be removed and the cortex penetrated with a suitable drill bit. The harvested bone is put aside. A cannulated compactor with a diameter of 7.0 mm (Richard Wolf, Knittlingen, Germany) is introduced into the femoral tunnel to a depth of 10 mm. It serves as a stop for the subsequent drilling operation from the outside. The K-wire is advanced to the level of the skin on the lateral thigh. A 12-mm incision is made over the wire tip (Fig 21). The K-wire is advanced and overdrilled down to the compactor with a drill bit of 11 mm, matching the
Femoral tunnel A notchplasty will not be performed routinely if the notch appears to be of adequate size. The notch is debrided using a curette and motorized instruments. At the level of the posterior border of the notch, a portion of the periosteum is pushed off with a rasp to provide for accurate seating of the femoral drill guide. The 4 mm offset femoral guide is introduced into the joint through the anteromedial portal. The tip of the Kirschner wire is placed into the center of the anatomic insertion of the original ACL at the 2 o’clock position in a left knee. It is then drilled approximately 1 or 2 mm into the cortex. The C-arm, which is initially positioned at the end of the table, is
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Fig. 15. Horizontal skin incision.
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Fig. 16. The gracilis tendon is inserted into an open stripper (Courtesy of Richard Wolf, Knittlingen, Germany).
knot diameter of the semitendinosus graft, using the compactor as a drill centering aid (Fig. 22). Next, the drill is replaced by a stepped compactor (Richard Wolf, Knittlingen, Germany), which is driven in, under arthroscopic vision, until its graduated 10-mm-long stepped leading portion protrudes approximately 3 mm from the tunnel into the notch (Fig. 23). In this process, the remaining cancellous bone is compacted against the cortex. This manifests itself in a change to a higher pitch of the blows driving in the compactor. The edge of the femoral tunnel is contoured. A Mersilene holding suture is passed through the joint
with the aid of a K-wire. If there are any doubts about a possible posterior wall blow out, the arthroscope may be inserted through the lateral side into the tunnel to visualize the posterior wall.
Fig. 17. The stripped hamstring tendons with their periosteal insertion.
Fig. 18. The ends of each tendon are tied together in a simple knot.
Tibial tunnel The tibial drill guide is inserted with the knee in 90° of flexion. As a landmark, we use the inner rim of the anterior horn of the lateral meniscus [54]. A 2.5-mm guide-wire is then inserted. Its position is confirmed by C-arm imaging. An impingement probe is mounted over the guide-wire. The knee is placed in
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Fig. 19. Measurement of the knot and the 2 loops in 0.5-mm steps.
Fig. 21. The K-wire is advanced to the level of the skin on the lateral thigh. A 12-mm incision is made over the pointing wire tip.
full extension. The impingement probe should have 2 mm of clearance to the notch roof. Next, the guide-wire is overdrilled with a cannulated reamer, whose size is determined by the diameter of the loops. Only the outer cortex is breached. The tibial tunnel is created using sequential compactors. Finally, the cannulated reamer is reinserted and the tibial plateau cortex is breached. To ease passage of the graft, the intra-articular tunnel entrance is debrided. The traction loop is pulled through the tibial tunnel with an arthroscopic grasper.
The knee is fully flexed. Using both hands, maximum traction is applied to both loops, and the knee taken through the full range of motion 20 times. This allows the knots to snug themselves down (Fig. 25).
Passing the graft The Mersilene tapes on the two grafts are pulled in from the lateral side. The gracilis loop with the thinner knot follows the semitendinosus loop (Fig. 24). The two loops are firmly pulled. A sudden jerk indicates that the semitendinosus knot has reached the step in the tunnel—the bottleneck. The knee is taken through a range of motion to ensure that there is no impingement.
Fig. 20. The prepared semitendinosus and hamstring tendon combined to a 4-strand hamstring graft.
Distal fixation of the graft For tibial fixation, we use the bone bridge technique as already described for bone patellar tendon graft fixation. With a suture placed through one end of each Mersilene tape, we railroad the tapes under the bridge, in a distal direction. With the knee flexed to about 10°, maximum traction is exerted on the Mersilene tapes, and the ends of the semitendinosus tape are first tied with a simple knot. Then, the knee is brought into full extension and the second knot is tied, followed by three knots. Stability is confirmed manually, and then the tapes of the second loop (gracilis) are tied in the same way. In a prospective, double-blind, randomized clinical trial, Dinevski et al [56] evaluated high (3.5 Mpa) and low levels (1.5 Mpa) of stress when tensioning
Fig. 22. The K-wire is advanced, and overdrilled down to the compactor with a drill bit of 11 mm, matching the knot diameter of the semitendinosus graft.
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Fig. 23. Under arthroscopic vision, a stepped compactor is driven from lateraly into the femoral tunnel up to the point that it hits and then pushes back the non-stepped compactor for about 10 mm (Courtesy of Richard Wolf, Knittlingen, Germany).
and high stress results in more elongation when compared with the low stress group. The wound is closed with a subcuticular stitch after having placed an intra-articular drain. If cancellous bone was harvested, it is used to impact the tibial tunnel for graft fixation. This technique is particularly useful in women with softer bone. A remaining segment of bone plug is impacted into the femoral tunnel to fill the space above the graft knots. Finally, stability is assessed with a sterile KT-1000 arthrometer or RolimeterTM (Aircast, Summit, NJ) (Fig. 26). Immediately after wound closure, a cryocompression system is applied, and the tourniquet is released. Rehabilitation We use the same rehabilitation for all three methods of ACL reconstruction. Postoperatively, an accel-
the graft with the knee at full extension on the tibial side. Results demonstrated that patients with low graft tension regain knee stability at a level closer to their uninjured knee in immediate postoperative measurements. Results over time indicate that both groups show graft lengthening over the first 6 months
Fig. 24. The tendons are pulled in from lateral side. The gracilis tendon follows the semitendinosus tendon.
Fig. 25. Conditioning of the graft.
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Fig. 26. Final stability assessment with a sterile RolimeterTM (Aircast, summit, NJ).
erated rehabilitation program is initiated to prevent arthrofibrosis and excessive quadriceps atrophy [57]. The patient goals of the early postoperative (3-week) phase are: (1) to achieve full passive hyperextension (removable extension splint); (2) to keep swelling to a minimum (cryotherapy and compression system); (3) to obtain wound healing; (4) to obtain 90° of flexion; and (5) to activate the quadriceps with straight leg raises. Quadriceps activation mobilizes the patella and stretches the patellar tendon, thus preventing patella baja and the so-called patellar entrapment syndrome. Partial weight-bearing with crutches is recommended for the first week. Thereafter, progression to full weight bearing is encouraged as tolerated. Jogging is allowed at 3 months, providing that the strength of the operated leg is 65% that of the unaffected leg. A period of 6 months is required for the patient to feel comfortable enough to return to unrestricted athletic activity. During the in-patient period, the patient undergoes physiotherapy, with prevention of lymphatic edema, and active exercises, such as cycling on the CamopedTM (Fa OPED, Valley, Germany), a bed bicycle. Bracing is used only for revisions, concomitant injuries, and meniscal repair.
Summary Bone—patellar tendon The ‘‘no hardware’’ technique for ACL reconstruction is a new method that offers many advantages and is straightforward to perform. Its main innovative feature is that it does not require bone-
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block harvesting from the patella. This reduces donor site morbidity and prevents patellar fractures. The bone tunnels are made using tube harvesters and compaction drilling. This minimizes trauma and obviates the risk of bone necrosis. The articular entrance of the tibial tunnel is completely occupied by the grafts. This prevents a windshield-wiper effect and synovial fluid ingress into the tunnel, and enhances graft incorporation. The fact that no hardware is used with both patellar tendon or hamstring grafts significantly reduces the overall cost of the operation and facilitates revision surgery. The quadriceps tendon is also a very good graft. It is thick and has good biomechanical properties and low donor site morbidity. Its disadvantages are: weakness of quadriceps after the operation, an unsightly scar, and some difficulty in graft harvesting [58]. Also, postoperative MRI is not fraught with the problem of metal artifacts. It is difficult to decide which of the methods currently available for ACL reconstruction is the best because most of them give satisfactory results. In the future, assessments of knee ligament reconstruction techniques should look at long-term stability combined with low complication rates. Ease of revision surgery and low cost should also be taken into consideration, given the large annual volume of knee ligament reconstructions (50,000 in the United States alone) [59]. We believe that our technique addresses most of these issues, and that it constitutes a useful alternative method for ACL reconstruction.
Semitendinosus—gracilis This technique, which was used with 915 patients from June 1998 to February 2002, shows a particularly low rate of postoperative morbidity. The reason is probably to be found in the ‘‘waterproofing’’ of the bone tunnels, which lead to less postoperative bleeding and swelling. No drains were used. Rehabilitation follows the same protocol as used for the reconstruction using patellar tendon grafts (accelerated/functional). As expected, there was no widening of the femoral tunnels and little widening of the tibial tunnels. Interestingly, tibial tunnel enlargement was significantly less in a nonaccelarated rehabilitation group than in the accelerated group [60] without affecting stability. The measured internal torque of the hamstrings, as well as their flexion force, already had returned to normal 12 months postoperatively. In a prospective randomized (unpublished) study comparing this technique with ACL reconstruction with BPT grafts with
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medial or lateral third with only one bone plug (from the tibial tuberosity, see technique described above), we found no significant difference between both groups in subjective scores, stability, KT-1000 values, Tegner activity score, and IKDC at 1-year follow-up. Only the results of kneeling and knee walking testing were significantly better in the hamstring group [61]. In summary, the advantages of this presented technique are: (1) the knot of the graft is close proximally to the anatomic site of the insertion of the ACL, thus avoiding the Bungee effect.; (2) the press-fit tunnel fixation prevents synovial fluid entering the bone tunnels, windshield-wiper effect, and longitudinal motion within the tunnel; the intensive contact between the bony wall of the tunnel and graft collagen over a long distance without any suture material results in quick and complete graft incorporation; and (3) no fixation material means no hardware problems, facilitates revision surgery, and lowers overall costs.
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Anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons, bone patellar tendon, or quadriceps tendon–graft with press-fit fixation without hardware A new and innovative procedure Hans H. Paessler, MD*, Dimitrios S. Mastrokalos, MD Center for Knee and Foot Surgery and Sport Injuries, ATOS—Clinic Heidelberg, Bismarckstrasse 9-15, Heidelberg 69115, Germany
The importance attached to the anterior cruciate ligament (ACL) as a knee stabilizer is reflected in the many techniques that have been developed for the surgical reconstruction of the ACL-deficient knee. There are three main reasons for this interest in the ACL: (1) ACL injuries are frequently encountered and may occur on an ‘‘epidemic’’ scale (downhill skiing); (2) ACL disruption results, not only in anterior instability, but also in meniscal lesions and in an increased rate of degenerative changes [1]; and (3) primary repair may not produce the desired outcome because the injured ACL has a notoriously poor healing potential, which has been attributed to the ACL cells’ inherently poor regeneration capacity, to the disruption of the ligament’s blood and nutritional supply, and to the complex geometry of the ACL [2 – 4].
Bone—patellar tendon Currently, the most frequently used autograft material for ACL reconstruction is the middle one third of the patellar tendon [5 – 7]; the bone blocks at either end are fixed with interference screws. Prob-
* Corresponding author. E-mail address: [email protected] (H.H. Paessler).
lems such as patellofemoral pain [8,9], patellar fractures [10 – 12], bone resorption around the implants [13], tunnel widening—especially of the tibial tunnel [14,15], and difficulties with hardware removal at revision surgery have, however, been reported. Graft harvesting The technique of bone-patellar tendon-bone (BPTB) autografts involves harvesting of the patellar tendon with two bone blocks, one from the tibial tubercle and one from the patella. The rationale advanced for this technique is that each bone block is inserted into a tunnel, usually secured with interference screws, allowing bone-to-bone healing, and, therefore, early aggressive rehabilitation. Patellofemoral pain, however, is a common and sometimes serious problem following ACL reconstruction with BPTB grafts. This complication has been reported in 40% to 60% of cases [16]. In a number of patients, secondary surgery for the retrieval of troublesome fixation hardware has been found to be required [17,18]. Patellofemoral pain and donor site morbidity appear to be unaffected by whether the patellar tendon defect is closed or left open [19]. In a small number of cases, patellar bone defects may cause patellar fractures at a subsequent stage, when the patella is exposed to stress during reha-
0030-5898/03/$ – see front matter D 2003, Elsevier Science (USA). All rights reserved. doi:10.1016/S0030-5898(02)00070-6
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bilitation [10,12]. Primary bone grafting of the patella has been proposed as a means of preventing such fractures [20]; its use does not appear, however, to have resulted in a significant reduction in the rate of this complication. Harvesting the tendon with a tibial tubercle bone block, but leaving the patella itself intact, reduces the time required for surgery, and it protects the patella from fracture. During follow-up, we have also observed that donor site morbidity is less following BPT compared with BPTB graft procedures, probably because the patellar bone remains intact. Another source of single-bone-block tendon grafts is the quadriceps tendon: Staeubli [21,22] reported excellent results with quadriceps tendon procedures and also found less morbidity compared with BPTB. Preparation of the bone tunnels Traditional methods use drilling for the creation of bone tunnels. Drilling is known to cause circumferential bone necrosis as a result of thermal damage [12,23]. This may contribute to delayed graft incorporation, and to eventual reconstructive failure [24]. With our method, drill bits are used exclusively for the perforation of the cortex. The cancellous bone of the femoral tunnel is removed using special bone cutting (harvester) tubes, whereas compaction drilling is used for tibial tunnel creation. This technique has three important advantages: (1) no drilling heat is produced; (2) the tunnel walls are smoother; and (3) a core of cancellous bone is produced for use in grafting the tibial donor site defect and for plugging the dead space in the tibial tunnel. Prevention of windshield-wiper and synovial-bathing effects Because the patellar tendon graft is flat, the crosssectional area of the tendinous graft portion is smaller than that of the bone block. As a result, the tendinous portion located at the articular entrance of the tibia bone tunnel does not completely fill the tunnel lumen. This allows transverse motion of the tendinous portion of the graft within the tunnel, a phenomenon known as the windshield-wiper effect [15]. This to-and-fro movement of the graft within the tunnel is an important cause of tunnel enlargement after ACL reconstruction [13]. Also, the dead space between the flat graft and the bone tunnel allows the ingress of synovial fluid (synovial-bathing effect), which exposes the bone to cytokines that may stimulate osteoclastic activity and bone resorption [25]. These phenomena may also be involved in tunnel enlargement.
Three Krackow sutures and one baseball stitch are placed into the distal 3 cm of the tendon. In this way, the discrepancy in diameter between the tibial tunnel and the bone-free end of the graft is abolished, and the graft should ‘‘plug and seal’’ the tunnel to prevent synovial fluid ingress. This should encourage more rapid graft incorporation. Also, the risk of tunnel widening should be minimized by the prevention of the windshield-wiper effect. Graft fixation Numerous methods for ACL graft fixation to bone have been proposed. Fixation techniques include staples, sutures tied to posts, interference screws, press-fit, and sutures tied over buttons. The goal of all these methods is to achieve firm fixation and to enable the graft to resist in vivo forces until it has been fully incorporated. Kurosaka [26] reported that, of the different fixation methods for patellar tendon grafts tested, the strongest fixation (475 N maximum load) was provided by the 9-mm interference screw. Steiner [27] found that the fixation strength of hamstring grafts secured with soft tissue washers was comparable to that of BPTB grafts secured with screws; the hamstring grafts, however, had less stiffness. The mean tensile strength provided by the locking-loop tendon-ligament suture developed by Krackow was found to be 223 N; using two locking-loop sutures, the strength was 392 N [28]. It was estimated by Noyes et al that the ACL encounters normal daily forces of between 20 N and 440 N [29]. Because patients are advised to reduce their activity during the postoperative period, the fixation techniques mentioned above may be assumed to protect the construct until the graft-bone interface has healed. Numerous clinical studies involving various fixation methods have reported high rates of excellent or good results [27,30 – 33]. Our method of graft fixation is a combination of a press-fit technique, on the femoral side; and press-fit plus sutures (locking-loop technique) tied over a 10-mm bone bridge as a post, on the tibial side. The femoral press-fit technique was first described by Hertel [34]. In a biomechanical study, Brown [35] compared press-fit fixation of the femoral bone plug (failure strength, 350 N) with fixation by means of interference screws, Endo-Button CLTM (Acufex, Smith and Nephew, MA), and MitekTM (Ethicon, Somerville, NJ) anchors. No statistically significant difference was found between these methods. Clinically, the press-fit technique has been shown to be safe. In a short follow-up (2 – 3 years), Boszotta [36] showed satisfactory results with the press-fit tech-
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nique. In a 10-year follow-up study, Hertel [31] reported excellent subjective and objective (eg, stability) results. It also has been demonstrated that the quadriceps tendon with one bone plug, which is fixed in the femoral tunnel, is an excellent graft with clinical outcome similar to patellar tendon. Krackow [28] found their suture technique to provide satisfactory soft-tissue fixation in ligament reconstruction surgery. Based on their findings, we have adopted a triple locking-loop stitch for tibial fixation, with the ends tied over a bone bridge. Shelbourne [37] reported a 94% success rate with sutures tied over buttons for the tibial fixation of BPTB grafts. Boszotta et al [38], in an experimental study, compared four different methods of tibial fixation (titanium interference screw, titanium staple, suture fixation over a bone bridge, and suture fixation over a bone bridge, with refilling of the tibial tunnel and the bone blocks gained from the preparation of femoral and tibial tunnel). He found that tibial fixation of the graft with sutures over a bone bridge with refilling of the tibial tunnel with bone blocks showed the highest failure load (758 N) (IF screw: 572N, staple: 608.4, sutures only: 304.5N). Ease of revision surgery Revision surgery after a failed ACL reconstruction is a challenging and difficult procedure. Among the many problems to be addressed is that of hardware removal. Removal of the fixation hardware may be very difficult—for example, if the screws have been overgrown by bone. Our ‘‘no hardware’’ technique obviates these problems and facilitates revision surgery.
Semitendinosus—gracilis Over the past few years, there has been increasing interest in the use of the semitendinosus tendon for ACL reconstruction because of the comparatively low postoperative morbidity. Pinczewski et al (2002) [39] recently reported 5-year results in a prospective study, comparing patellar tendon and 4-strand hamstring tendon graft for ACL reconstruction. Patellar tendon grafts appeared tighter clinically, and with lower KT 1000 measurements, up to 3 years postoperatively, compared with hamstring grafts, but thereafter the results were similar. Anderson et al [40] confirmed the 3-year results of Pinczewski et al [39] according to objective stability with a slight superiority of the bone patella tendon graft. The subjective results and the results from muscle strength testing
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were better in the hamstrings group. They found a worrying trend toward osteoarthritis developing in the patellar tendon group. Kneeling pain also remained a persistent problem in the patellar tendon group. According to their results, the passage of time seems to favor the hamstring group over the patellar tendon group. In many of the prospective studies published to date, however, the stability achieved with hamstring tendons was found to be inferior to that obtained with the patellar tendon [30,32,33,41]. In most of these studies, fixation away from the point of insertion with the Endo-Button technique was used. Hoeher et al [13] demonstrated in their experimental studies creep near the tendon-tape-transition with a give in of the tendon construct and a permanent elongation of 3.8+/ 0.8 mm. This so-called bungee effect may result in tunnel enlargement and graft failure. Recently, fixation techniques using metal or bioresorbable interference srews have been popularized. Van der Reis et al [42], however, compared different hamstring fixation devices under cyclic loading (Endo-Button CL, LinX-HT (Ethicon, Somerville, NJ), Trans-Fix (Arthrex, Naples, FL), Bioscrew (Arthrex, Naples, FL)). They found that all devices performed well under cyclic loading except the Bioscrew. Clatworthy et al [14] prospectively studied the effect of four different fixation techniques (Bioabsorbable IFSTM [Arthrex, Naples, FL], RCI-IFSTM [Smith and Nephew, MA], Bone MulchTM Screws/ Staples [Arthrotek, Warsaw, IN], Endo-Button/Staples [Arthrex, Naples, FL]) on tunnel widening in hamstring ACL reconstruction. As with Van der Reis et al [42], they showed that use of the bioscrew resulted in larger tunnel dilation. Our technique uses press-fit graft fixation of hamstring grafts close to the anatomic ACL insertion, thus eliminating both the bungee and windshield wiper effects and the need for any implant. The semitendinosus tendon and the gracilis tendons both are tied together by a simple knot, which is secured by nonabsorbable sutures. A bottle neck-like tunnel is created on the femoral side, in which the knot of the tendon loop is firmly secured just proximal to the cortex of the notch wall at the anatomic insertion.
Biomechanical testing In cooperation with A. Weiler, MD and F. Kandziora, MD (unpublished data, 1999) biomechanical pull-out tests on pig knees have shown that under cyclic loading (100 x 300 N, 100 x 400 N, 100 x 500 N, 100 x 600 N, and 100 x 700 N)
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this technique was demonstrated to be twofold stronger than the ‘‘Gold Standard’’ BTB fixed with interference screws. In this article, two new techniques for ACL reconstruction with press-fit fixation are presented: (1) a BPT without a bone block from the patella or a quadriceps tendon graft with a bone block, and (2) a semitendinosus—gracilis graft. These methods overcome many of the complications mentioned above, or the rate of these complications is low.
Surgical technique Setup We use the same setup for all three grafts. The operation may be performed under either general or regional anesthesia. A pneumatic tourniquet is placed on the proximal thigh of the injured leg, but generally not inflated. An infusion pump allows the procedure to be performed without tourniquet control. The operating table is angled at knee level, to allow the injured leg to hang over the edge of the table. A lateral post is used for applying a valgus force. The opposite leg is abducted and positioned straight. A VenaFlowTM system (Aircast, Summit, NJ), which provides pneumatic compression to the lower leg for the prevention of deep vein thrombosis (DVT), is applied to the uninvolved leg. The device is intermittently inflated and deflated during the operation. Standard arthroscopic equipment consists of a 30° arthroscope, arthroscopic cannulas, cannulated drills, and a motorized burr. Under anesthesia, the knee is examined meticulously, using the full range of stability tests. In addition, knee laxity measurement is performed using a KT-1000TM arthrometer (MEDmetric, San Diego, CA). Before skin incision, a first-generation cephalosporin is given intravenously. At the same time, 0.375 mL/kg of 0.25% bupivacaine hydrochloride with adrenaline 1 in 100,000 is instilled into the knee joint, into the area of skin incision for graft harvesting and into the portals. This provides hemostasis and reduces postoperative pain.
tuberosity might be reasons of donor site morbidity. Therefore, we prefer a subcutaneous graft-harvesting technique with a double incision that avoids injury to the infrapatellar nerve. With the knee flexed to 90°, a 25-mm vertical incision is made just above the tibial tubercle. The medial and lateral borders of the patellar tendon are identified easily by retracting the skin in either direction. The tendon sheath is divided lengthwise and dissected up to the lower pole of the patella. We prefer the medial or lateral third of the patellar tendon although some authors [44] report good results with the medial third of the patellar tendon. Matarazzo et al [45] showed that harvesting of either the medial or lateral third of the patellar tendon results in significantly less donor site morbidity than the central third. The medial or lateral third of the patella, furthermore, are longer than the central one. The medial or lateral one third of the patellar tendon is sharply incised with parallel incisions, using a standard Smillie meniscus knife (Sklar, West Chester, PA) to create an 11-mm-wide graft. The tibial 25to 30-mm bone block with a diameter of 9 to 10 mm is harvested using a narrow oscillating saw. Once the bone block has been harvested, the knee is placed in full extension. A second 20-mm vertical incision subsequently is made along the apex of the patella. The prepatellar bursa and the paratendon are incised down to the aponeurosis. A sharp towel clamp is pushed under the skin and the paratenon from the proximal incision and out through the distal incision. The distal bone block is grasped with the clamp and pulled in the proximal direction under the paratenon and out through the proximal incision (Fig. 1). The
Bone—patellar tendon graft Graft harvesting Kartus et al [43] recommend avoidance of intraoperative injury of the infrapatellar nerve because this fact and the harvesting of one block from the tibial
Fig. 1. Harvesting of patellar tendon graft using two small horizontal incisions.
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graft is subperiosteally stripped off the patella, over a distance of 20 to 25 mm (Fig. 2). Fulkerson et al [46] described a simple technique of harvesting a quadriceps graft. The quadriceps tendon is harvested with a bone plug from the patella. Graft preparation The bone block is trimmed to form a cylindrical plug, usually 9-10 mm in diameter. Next, a drill hole is made in the bone plug, and a holding suture (Mersilene No 3) is passed through it. A baseball stitch (Vicryl #1) and three Krackow locking-loop stitches (Ethibond No 2) are placed in the distal 3 cm of the bone-free end of the tendon (Fig. 3). The diameter is checked by passing the tendon end through cylindrical sizers that are supplied in halfmillimeter increments.
Fig. 3. The free end of the graft is armed with three Krackow sutures and distal baseball stitch. The bone block is trimmed cylindrically.
Under arthroscopic visualization, any ACL remnants are removed with a shaver, and notchplasty is performed using a motorized burr to enlarge the notch roof. Next, the femoral tunnel is prepared. Our positioning of the femoral tunnel derives from the experimental findings of Hefzy [47] regarding the most isometric attachment of the ACL. It is widely accepted that an ACL graft should be positioned at the original anatomic position at 10’clock [48 – 52]. In a recent prospective in vivo study (publication in process) we evaluated whether a guide pin for a femoral tunnel could be positioned through the tibial tunnel into the center of the anatomic ACL attachment. The study confirms the results of a recent
cadaveric study by Arnold et al [53] that transtibial femoral-tunnel drilling does not reach the anatomic site of the ACL insertion, even with larger tibial tunnels (for hamstring grafts up to 8.5 mm). This may explain why in many studies in which hamstring grafts and transtibial tunnel drilling were used, an increase of laxity compared with patellar tendon grafts is observed. Therefore, we prefer drilling of the femoral tunnel through the anteromedial portal. A femoral over-the-top drill guide, with an offset of 6 mm, is used for accurate placement of a 2-mm K-wire at 10 o’clock (right knee) or 2 o’clock (left knee) under fluoroscopic control. With the knee flexed to 120 to 130 degrees, the K-wire is drilled through the femoral condyle until it protrudes through the skin of the thigh (Fig. 4). A hard copy of this fluoroscopic image is made and added to the patient’s chart to complement the set of arthroscopic images. Using atraumatic cannulated reamers, only the medial cortex is over-reamed to the measured diameter of the cylindrical bone plug of the graft (Fig. 5). The cancellous bone is removed using a harvester tube 1 mm
Fig. 2. The graft is subperiosteally stripped off the patella, over a distance of 20 – 25 mm.
Fig. 4. Placing of a 5-mm offset drill guide in the over-thetop position.
Femoral tunnel
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Fig. 5. With use of atraumatic cannulated reamers, only the medial cortex is over-reamed to the measured diameter of the cylindrical bone plug of the graft.
smaller in diameter than the bone block itself; the harvested plug is preserved for subsequent implantation into the tibial tunnel (Fig. 6). A K-wire with an eyelet is introduced into the femoral tunnel and drilled through the anterolateral cortex for the passage of a guide suture, which will be used to pull the suture attached to the bone plug. Tibial tunnel The knee is flexed to 90°, and preparation of the tibial tunnel is begun. A recent study [54] demonstrated that the inner rim of the anterior horn of the lateral meniscus corresponds well with the midpoint of the ACL footprint. Using the tibial drill guide, a 2.5-mm drill bit is advanced through the skin incision, medial to the tubercle and into the joint. At this stage, in order to guard against later graft impingement, a special impingement probe is intro-
Fig. 7. A special impingement probe is introduced through the anteromedial portal and placed on the 2.5-mm K-wire.
duced through the anteromedial portal and placed on the drill bit. When the knee is taken into full extension, there should be a clearance of about 3 mm between the notch roof and the probe (Fig. 7). After confirmation of correct placement of the 2.5-mm drill bit, the tibial cortex is pierced with a 6.5-mm or a 7-mm reamer (depending on the diameter of the patellar tendon). This is followed by compaction drilling with a dilator of the same diameter, to compact the cancellous bone surrounding the tibial tunnel. The cortex of the tibial plateau is drilled under arthroscopic visualization (Fig. 8).
Fig. 6. Bone harvesting tube is tapped 30 mm deep into the femur.
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through the tibial tunnel with a guide suture. Isometry is tested. Over the full range of motion, the movement of the graft should be less than 2 mm; in hyperextension the substitute ACL should be tense. In hyperextension, a check is also made to ensure that there is sufficient clearance between the graft and the anterior border of the notch (impingement test). Using a 4.5-mm drill bit, a drill hole is made 1 cm distal to the exit of the tibial tunnel. With a curved clamp, a bone tunnel is created in the cancellous bone, and a cortical bone bridge is fashioned, over which the sutures will be tied (Fig. 11). With the knee in full extension, half of the sutures attached to the tendon end are passed under the bridge and tied to the remaining sutures, which have been passed over the bridge (Fig. 12). A check is made to ensure that the range of motion is full, and a Lachman test is performed. Finally, one half of the harvested bone core is packed into the tibial tunnel (Fig. 13), and the other half is placed in the tibial tubercle donor site. The patellar tendon deficit is closed by juxtaposing the edges of the outermost layer with a continous Vicryl (Ethicon, Somerville, NJ) suture. Another Vicryl suture is used to close the retinaculum and Fig. 8. The cortex of the tibial plateau is drilled under arthroscopic visualization.
Any tissue remnants anterior to the tunnel mouth are removed to prevent the formation of a cyclops syndrome lesion postoperatively. Graft placement for both patellar and quadriceps tendon The suture attached to the bone plug of the graft is pulled through the femoral drill hole by the guide suture. Firm traction on the graft sutures will make the graft slide into the joint through the anteromedial portal, and the bone plug will enter the femoral tunnel. With the knee flexed to 120°, a special impactor with two spikes (Fig. 9) is used to drive the cylindrical plug into the femoral tunnel, in such a way as to make the bone plug cortex face posteriorly in the tunnel, to obtain posterior alignment of the collagen fibers of the graft. The angle between the bone plug cortex and the long axis of the femur should be 25° (Fig. 10). The free end of the graft is twisted to make the graft fibers facing the posterior cruciate ligament (PCL) lie anteriorly to produce an anteromedial and a posteromedial bundle. Then, the holding sutures on the free end of the graft are pulled
Fig. 9. A special impactor with two spikes used for impaction the femoral bone block.
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Fig. 10. With the special impactor, the bone block of the graft is tapped into the femoral socket.
the tendon sheath. Finally, 0.300 mL/kg of 0.25% bupivacaine hydrochloride with adrenaline 1 in 100,000, and 1 ampoule of morphine (10 mg) are injected intra-articularly. A thin compression dressing is applied over the wound, and a Cryo/CuffR knee compression system (Aircast Inc., Summit, NJ), which has been shown to provide control of swelling and bleeding postoperatively [55], is placed around the knee (Fig. 14). In addition, the operated leg is also fitted with a VenaFlow system,while the patient is in the recovery room.
Semitendinosus—gracilis graft Graft harvesting With the knee flexed to 90°, a 2-cm incision is used 3 cm medial and distal to the tibial tuberosity,
Fig. 11. Tibial fixation: with a 4.5-drill bit, a drill hole is created 1-cm distal to the tibial tunnel exit and a cortical bone bridge is fashioned using a curved clamp over which the sutures will be tied.
Fig. 12. The graft sutures are tied over the bone bridge.
parallel to the lines of the skin, to avoid damage to the inferior branch of the saphenous nerve, and for cosmesis (Fig. 15). The bursa of the pes is incised and split proximally. Both the tendons are visualized and mobilized. First the gracilis tendon is grasped using a curved clamp. Maximal traction is applied, which releases the ‘‘web-like’’ fascia slips. The gracilis tendon is inserted into an open stripper (Richard Wolf, Knittlingen, Germany), which is advanced proximally about 25 cm (Fig. 16). At this point, the tendon is cut by closing the stripper. The tendon remains attached to the periosteum, and the semitendinosus is harvested in a similar manner. Finally, the tendons are stripped off the tibia with their periosteal insertion (Fig. 17). On the workstation, the tendons are gently dissected free of muscle tissue. The ends of each tendon are tied together in a simple knot (Fig. 18). The knots are maximally tightened under cyclic manual load.
Fig. 13. The cancellous bone cores are introduced and tapped into the tibial tunnel.
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Fig. 14. The Cryo-CuffTM knee compression system (Aircast Inc., Summit, NJ).
With the help of a Merslilene (Ethicon, Somerville, NJ) tape, the loops are pulled one after the other through a measuring template in 0.5-mm site increments in order to find the smallest diameter of both loops (Fig. 19). To distinguish between the loops, different-colored Mersilene tapes are used. The diameter of the knots should be 4 mm more than the diameter of the loops. The grafts are mounted to the workstation. The knots are secured with 4 diverging U-shaped Ethibond No 2 (Ethicon, Somerville, NJ) sutures (Fig. 20). The loop length after knotting is equal to the cortical thickness, about 5 to 6mm, plus the intraarticular graft length, about 30 mm,and the length of the tibial tunnel at 45°, about 40 mm. This totals 75 mm for the semitendinosus tendon, and 85 mm for the gracilis tendon. The gracilis loop must be longer because the knot of the gracilis tendon will be proximal to the semitendinosus knot. The intra-articular portions of the graft are marked.
now moved to the joint for positioning of the tip of the Kirschner wire. The ideal position of the tip is on an imaginary line continuing from the posterior cortex of the distal femur, approximately 5 to 7 mm inferior to Blumenstaat’s line. The knee is then flexed to 125°. The K-wire is inserted into the cortex to a depth of approximately 5 mm. The drill guide is removed, and the femoralK-wire overdrilled with a cannulated reamer, matching the diameter of the two loops. If harvesting of cancellous bone graft is desired, then the reamer is advanced cautiously until it reaches the cancellous bone at a depth of 5 to 7 mm; it is then withdrawn. The appropriate harvester tube (Richard Wolf, Knittlingen, Germany) is selected from the range of tubes provided in 0.5 mm increments. The harvester tube is inserted and advanced beyond the lateral cortex. In young subjects, with a very hard cortex, the tube should be removed and the cortex penetrated with a suitable drill bit. The harvested bone is put aside. A cannulated compactor with a diameter of 7.0 mm (Richard Wolf, Knittlingen, Germany) is introduced into the femoral tunnel to a depth of 10 mm. It serves as a stop for the subsequent drilling operation from the outside. The K-wire is advanced to the level of the skin on the lateral thigh. A 12-mm incision is made over the wire tip (Fig 21). The K-wire is advanced and overdrilled down to the compactor with a drill bit of 11 mm, matching the
Femoral tunnel A notchplasty will not be performed routinely if the notch appears to be of adequate size. The notch is debrided using a curette and motorized instruments. At the level of the posterior border of the notch, a portion of the periosteum is pushed off with a rasp to provide for accurate seating of the femoral drill guide. The 4 mm offset femoral guide is introduced into the joint through the anteromedial portal. The tip of the Kirschner wire is placed into the center of the anatomic insertion of the original ACL at the 2 o’clock position in a left knee. It is then drilled approximately 1 or 2 mm into the cortex. The C-arm, which is initially positioned at the end of the table, is
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Fig. 15. Horizontal skin incision.
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Fig. 16. The gracilis tendon is inserted into an open stripper (Courtesy of Richard Wolf, Knittlingen, Germany).
knot diameter of the semitendinosus graft, using the compactor as a drill centering aid (Fig. 22). Next, the drill is replaced by a stepped compactor (Richard Wolf, Knittlingen, Germany), which is driven in, under arthroscopic vision, until its graduated 10-mm-long stepped leading portion protrudes approximately 3 mm from the tunnel into the notch (Fig. 23). In this process, the remaining cancellous bone is compacted against the cortex. This manifests itself in a change to a higher pitch of the blows driving in the compactor. The edge of the femoral tunnel is contoured. A Mersilene holding suture is passed through the joint
with the aid of a K-wire. If there are any doubts about a possible posterior wall blow out, the arthroscope may be inserted through the lateral side into the tunnel to visualize the posterior wall.
Fig. 17. The stripped hamstring tendons with their periosteal insertion.
Fig. 18. The ends of each tendon are tied together in a simple knot.
Tibial tunnel The tibial drill guide is inserted with the knee in 90° of flexion. As a landmark, we use the inner rim of the anterior horn of the lateral meniscus [54]. A 2.5-mm guide-wire is then inserted. Its position is confirmed by C-arm imaging. An impingement probe is mounted over the guide-wire. The knee is placed in
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Fig. 19. Measurement of the knot and the 2 loops in 0.5-mm steps.
Fig. 21. The K-wire is advanced to the level of the skin on the lateral thigh. A 12-mm incision is made over the pointing wire tip.
full extension. The impingement probe should have 2 mm of clearance to the notch roof. Next, the guide-wire is overdrilled with a cannulated reamer, whose size is determined by the diameter of the loops. Only the outer cortex is breached. The tibial tunnel is created using sequential compactors. Finally, the cannulated reamer is reinserted and the tibial plateau cortex is breached. To ease passage of the graft, the intra-articular tunnel entrance is debrided. The traction loop is pulled through the tibial tunnel with an arthroscopic grasper.
The knee is fully flexed. Using both hands, maximum traction is applied to both loops, and the knee taken through the full range of motion 20 times. This allows the knots to snug themselves down (Fig. 25).
Passing the graft The Mersilene tapes on the two grafts are pulled in from the lateral side. The gracilis loop with the thinner knot follows the semitendinosus loop (Fig. 24). The two loops are firmly pulled. A sudden jerk indicates that the semitendinosus knot has reached the step in the tunnel—the bottleneck. The knee is taken through a range of motion to ensure that there is no impingement.
Fig. 20. The prepared semitendinosus and hamstring tendon combined to a 4-strand hamstring graft.
Distal fixation of the graft For tibial fixation, we use the bone bridge technique as already described for bone patellar tendon graft fixation. With a suture placed through one end of each Mersilene tape, we railroad the tapes under the bridge, in a distal direction. With the knee flexed to about 10°, maximum traction is exerted on the Mersilene tapes, and the ends of the semitendinosus tape are first tied with a simple knot. Then, the knee is brought into full extension and the second knot is tied, followed by three knots. Stability is confirmed manually, and then the tapes of the second loop (gracilis) are tied in the same way. In a prospective, double-blind, randomized clinical trial, Dinevski et al [56] evaluated high (3.5 Mpa) and low levels (1.5 Mpa) of stress when tensioning
Fig. 22. The K-wire is advanced, and overdrilled down to the compactor with a drill bit of 11 mm, matching the knot diameter of the semitendinosus graft.
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Fig. 23. Under arthroscopic vision, a stepped compactor is driven from lateraly into the femoral tunnel up to the point that it hits and then pushes back the non-stepped compactor for about 10 mm (Courtesy of Richard Wolf, Knittlingen, Germany).
and high stress results in more elongation when compared with the low stress group. The wound is closed with a subcuticular stitch after having placed an intra-articular drain. If cancellous bone was harvested, it is used to impact the tibial tunnel for graft fixation. This technique is particularly useful in women with softer bone. A remaining segment of bone plug is impacted into the femoral tunnel to fill the space above the graft knots. Finally, stability is assessed with a sterile KT-1000 arthrometer or RolimeterTM (Aircast, Summit, NJ) (Fig. 26). Immediately after wound closure, a cryocompression system is applied, and the tourniquet is released. Rehabilitation We use the same rehabilitation for all three methods of ACL reconstruction. Postoperatively, an accel-
the graft with the knee at full extension on the tibial side. Results demonstrated that patients with low graft tension regain knee stability at a level closer to their uninjured knee in immediate postoperative measurements. Results over time indicate that both groups show graft lengthening over the first 6 months
Fig. 24. The tendons are pulled in from lateral side. The gracilis tendon follows the semitendinosus tendon.
Fig. 25. Conditioning of the graft.
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Fig. 26. Final stability assessment with a sterile RolimeterTM (Aircast, summit, NJ).
erated rehabilitation program is initiated to prevent arthrofibrosis and excessive quadriceps atrophy [57]. The patient goals of the early postoperative (3-week) phase are: (1) to achieve full passive hyperextension (removable extension splint); (2) to keep swelling to a minimum (cryotherapy and compression system); (3) to obtain wound healing; (4) to obtain 90° of flexion; and (5) to activate the quadriceps with straight leg raises. Quadriceps activation mobilizes the patella and stretches the patellar tendon, thus preventing patella baja and the so-called patellar entrapment syndrome. Partial weight-bearing with crutches is recommended for the first week. Thereafter, progression to full weight bearing is encouraged as tolerated. Jogging is allowed at 3 months, providing that the strength of the operated leg is 65% that of the unaffected leg. A period of 6 months is required for the patient to feel comfortable enough to return to unrestricted athletic activity. During the in-patient period, the patient undergoes physiotherapy, with prevention of lymphatic edema, and active exercises, such as cycling on the CamopedTM (Fa OPED, Valley, Germany), a bed bicycle. Bracing is used only for revisions, concomitant injuries, and meniscal repair.
Summary Bone—patellar tendon The ‘‘no hardware’’ technique for ACL reconstruction is a new method that offers many advantages and is straightforward to perform. Its main innovative feature is that it does not require bone-
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block harvesting from the patella. This reduces donor site morbidity and prevents patellar fractures. The bone tunnels are made using tube harvesters and compaction drilling. This minimizes trauma and obviates the risk of bone necrosis. The articular entrance of the tibial tunnel is completely occupied by the grafts. This prevents a windshield-wiper effect and synovial fluid ingress into the tunnel, and enhances graft incorporation. The fact that no hardware is used with both patellar tendon or hamstring grafts significantly reduces the overall cost of the operation and facilitates revision surgery. The quadriceps tendon is also a very good graft. It is thick and has good biomechanical properties and low donor site morbidity. Its disadvantages are: weakness of quadriceps after the operation, an unsightly scar, and some difficulty in graft harvesting [58]. Also, postoperative MRI is not fraught with the problem of metal artifacts. It is difficult to decide which of the methods currently available for ACL reconstruction is the best because most of them give satisfactory results. In the future, assessments of knee ligament reconstruction techniques should look at long-term stability combined with low complication rates. Ease of revision surgery and low cost should also be taken into consideration, given the large annual volume of knee ligament reconstructions (50,000 in the United States alone) [59]. We believe that our technique addresses most of these issues, and that it constitutes a useful alternative method for ACL reconstruction.
Semitendinosus—gracilis This technique, which was used with 915 patients from June 1998 to February 2002, shows a particularly low rate of postoperative morbidity. The reason is probably to be found in the ‘‘waterproofing’’ of the bone tunnels, which lead to less postoperative bleeding and swelling. No drains were used. Rehabilitation follows the same protocol as used for the reconstruction using patellar tendon grafts (accelerated/functional). As expected, there was no widening of the femoral tunnels and little widening of the tibial tunnels. Interestingly, tibial tunnel enlargement was significantly less in a nonaccelarated rehabilitation group than in the accelerated group [60] without affecting stability. The measured internal torque of the hamstrings, as well as their flexion force, already had returned to normal 12 months postoperatively. In a prospective randomized (unpublished) study comparing this technique with ACL reconstruction with BPT grafts with
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medial or lateral third with only one bone plug (from the tibial tuberosity, see technique described above), we found no significant difference between both groups in subjective scores, stability, KT-1000 values, Tegner activity score, and IKDC at 1-year follow-up. Only the results of kneeling and knee walking testing were significantly better in the hamstring group [61]. In summary, the advantages of this presented technique are: (1) the knot of the graft is close proximally to the anatomic site of the insertion of the ACL, thus avoiding the Bungee effect.; (2) the press-fit tunnel fixation prevents synovial fluid entering the bone tunnels, windshield-wiper effect, and longitudinal motion within the tunnel; the intensive contact between the bony wall of the tunnel and graft collagen over a long distance without any suture material results in quick and complete graft incorporation; and (3) no fixation material means no hardware problems, facilitates revision surgery, and lowers overall costs.
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