Arthroscopic Posterior Cruciate Ligament Augmentation Using an Autogenous Hamstring Tendon Graft and the Posterior-Posterior Triangulation Technique

We describe a modification of the currently practiced arthroscopic posterior cruciate ligament (PCL) reconstruction techniques. We augmented the injured PCL with quadrupled autogenous hamstring tendon grafts using the arthroscopic posterior-posterior triangulation method and a single-incision transtibial approach. The tibial drill guide was introduced through the anteromedial portal and positioned onto the fossa for the PCL on the tibia under arthroscopic guidance from the posterolateral portal. The femoral tunnel was made 10 mm posterior to the articular cartilage of the medial femoral condyle by use of the anterior cruciate ligament Beath pin (Arthrex, Naples, FL) introduced through the far-inferior anterolateral portal. The tendon graft was positioned in the knee joint by use of the tibial and femoral double-folded silk loops that traversed the bony tunnels. The graft was fixed by use of bioabsorbable Intrafix screw systems (DePuy Mitek, Raynham, MA) at both the ends. The arthroscopic posterior-posterior triangulation method provides adequate exposure of the posterior knee compartment; this allows for convenient instrumentation and safe and accurate placement of the bony tunnels with preservation of the PCL remnants. We believe that retention of the remnant PCL fibers is biologic and contributes to earlier healing and strengthening of the tendon graft.     

The acorn Beath couple: articular salvation for double-bundle femoral tunnels in cruciate ligament reconstruction

With the recent increase in interest in arthroscopic double-bundle cruciate reconstructions, efficient, safe, and reproducible techniques are needed. This technical trick is applicable to both arthroscopic anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction when double-bundle femoral tunnels are performed through an accessory far lateral or far medial incision as with the all-inside femoral tunnel drilling approach. A standard double-bundle cruciate reconstruction technique is applied until placement of the femoral footprint Beath pins in anticipation of tunnel drilling. Femoral footprint targeting with a Beath pin requires use of a far accessory portal. Before the long Beath pin is introduced into the joint, an acorn reamer is placed over the Beath pin to within 5 mm of the pin tip, thus creating an acorn Beath couple. The eyelet pin end is loaded onto a quick-release pin collet driver, leaving the acorn reamer free to turn. The acorn Beath couple is then introduced into the appropriate accessory portal and positioned in the center of the desired femoral footprint. An assistant holds the acorn reamer shaft while the Beath pin is advanced. The collet driver is then disengaged from the pin and replaced with an adjustable chuck and secured to the acorn reamer shaft of the acorn Beath couple. The femoral tunnel is drilled to the appropriate depth, and the Beath pin is pulled out the anterior thigh. Doing so disengages the acorn reamer and allows for safe removal of the reamer from the notch. The technique is then repeated with the coupling of a 4.5 Endobutton reamer and the Beath pin.     

Anatomic double-bundle anterior cruciate ligament reconstruction with hamstrings

This article describes a double-bundle gracilis and semitendinosus technique that guarantees a more anatomic anterior cruciate ligament (ACL) reconstruction and allows the surgeon to avoid the use of hardware for graft fixation. The tendons are harvested maintaining their tibial insertion. Sutures are tightened at the free proximal tendon ends to obtain a sufficient strength to traction. The tibial tunnel is located in the medioposterior part of the ACL tibial insertion. For the femoral tunnel, the knee is flexed around 130° and the guide pin is advanced until it passes the femoral cortex. The exit point in the lateral aspect of the femur should be immediately above the end of the lateral femoral condyle. After the lateral incision, the tendons are passed over the top. The correct placement is found by palpating the posterior tubercle of the lateral femoral condyle with a finger. The stitches on the free end of the tendons are tied onto the passing suture that is pulled through the knee joint into the over-the-top position. A suture loop is introduced into the joint through the anteromedial portal using a suture passer and then pulled into the femoral tunnel under the arthroscopic view. The stitches on the free end of the tendons are looped again onto the passing suture, which is pulled through the femoral tunnel, knee joint, and tibial tunnel to retrieve the graft from the tibial incision. The combined gracilis and semitendinosus tendons are then tensioned and secured with a transosseus suture knot. This technique attempts to reproduce the kinematic effect of both anteromedial and posterolateral bundle of the ACL with a 4-bundle reconstruction with a better performance from the anatomic and functional point of view.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 5 (May-June), 2003: pp 540–546     

单隧道双束腘绳肌腱双Intrafix固定重建前交叉韧带近期疗效观察

目的 探讨单隧道双束腘绳肌腱双Intrafix固定重建前交叉韧带(ACL)中应用的可行性及近期疗效.方法 对30例ACL损伤患者行关节镜下单隧道双束腘绳肌腱ACL重建术.采用膝关节镜前内侧入路(AM)建立股骨隧道,胫骨端用点对点ACL瞄准器建立隧道.隧道股骨端采用Femoral-Intrafix固定将腘绳肌腱分为前内侧束及后外侧束.通过旋转胫骨端移植物,将移植物调整为生理的双束位置,采用Bio-Intrafix固定胫骨端.结果 30例均获随访,时间6～8个月.根据Lysholm膝关节功能评分:术前为19～58(33.17±11.71)分;术后6个月为88～98(95.30±2.10)分(t=30.20,P<0.01).结论 单隧道双束腘绳肌腱双Intrafix固定重建ACL,手术操作简便,固定牢固,近期效果满意.     

Medial portal technique for single-bundle anatomical Anterior Cruciate Ligament (ACL) reconstruction

The aim of the paper is to describe the medial portal technique for anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Placement of an ACL graft within the anatomical femoral and tibial attachment sites is critical to the success and clinical outcome of ACL reconstruction. Non-anatomical ACL graft placement is the most common technical error leading to recurrent instability following ACL reconstruction. ACL reconstruction has commonly been performed using a transtibial tunnel technique in which the ACL femoral tunnel is drilled through a tibial tunnel positioned in the posterior half of the native ACL tibial attachment site. ACL reconstruction performed using a transtibial tunnel technique often results in a vertical ACL graft, which may fail to control the combined motions of anterior tibial translation and internal tibial rotation which occur during the pivot-shift phenomenon. The inability of a vertically oriented ACL graft to control these combined motions may result in the patient experiencing continued symptoms of instability due to the pivot-shift phenomenon. The medial portal technique in which the ACL femoral tunnel is drilled through an anteromedial or accessory anteromedial portal allows consistent anatomical ACL tunnel placement. This paper describes the advantages of the medial portal technique, indications for the technique, patient positioning, proper portal placement, anatomical femoral and tibial tunnel placement, graft tensioning and fixation.     

Interference screw divergence in femoral tunnel fixation during endoscopic anterior cruciate ligament reconstruction using hamstring grafts

Purpose:To compare the divergence angles between bioabsorbable interference screws inserted into the femoral tunnel with the screwdriver placed through the anteromedial portal to those inserted with the screwdriver placed through the tibial tunnel and to examine the effect of the femoral tunnel interference screws’ divergence angles on fixation strength of hamstring grafts after anterior cruciate ligament (ACL) reconstruction using hamstring grafts. Type of Study:Cadaveric biomechanical pullout study. Methods:ACL reconstruction was performed in 8 pairs of fresh-frozen human cadaveric knees using hamstring grafts fixed within the femoral tunnels using bioabsorbable interference screws. Within matched pairs, 1 screw was placed into the femoral tunnel using a screwdriver placed through the tibial tunnel (group 1), and in the other knee it was placed into the femoral tunnel using a screwdriver placed through the anteromedial portal (group 2). Radiographs were taken to measure the degree of divergence between the interference screw and the femoral tunnel. After disarticulation, pullout strength was then measured using a cyclic-loading model. Results:In group 2, there was significantly more divergence between the screw and the femoral tunnel compared with group 1, particularly in the sagittal plane (average 14.4° compared with 3.4°, P =.00014). With the number of specimens available for comparison, no significant difference was detected between the 2 groups with regard to 3 mm and 5 mm of pullout when cyclically loaded (P =.77 and.74, respectively). Conclusions: The increased technical difficulty, combined with the potential risks of tibial tunnel widening and graft damage, with placement of the screwdriver through the tibial tunnel for the purpose of decreasing femoral interference screw divergence in ACL reconstruction using hamstring grafts may not be justified.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 5 (May-June), 2002: pp 510–514     

Femoral fixation of hamstring tendon autografts using the TransFix device with additional bone grafting in an anteromedial portal technique

Background The femoral fixation of hamstring tendon grafts by a cross-pin is an established method with excellent biomechanical properties. Until now, this surgical procedure was associated with a transtibial placement of the femoral tunnel and a graft-tunnel diameter mismatch due to the different volumes of the tendon loop and the tendon strands. Methods By use of an electrical knee positioning device, the transfixation technique can be performed safely through the anteromedial arthroscopic portal (transarticular technique), reaching the optimal lateral '10:30' position in the intercondylar notch. By use of a specific harvesting and implantation device, a cancellous bone plug is harvested and inserted into the femoral tunnel, thus stabilizing the tendon bundle and eliminating dead space in the tunnel. Conclusion The femoral cross-pin guarantees a secure anchorage of the graft, drilling through the anteromedial portal eases optimum tunnel placement, and the insertion of a solid cancellous bone plug eliminates the femoral graft-tunnel diameter discrepancy and improves the press-fit contact between graft and tunnel wall. The long-term benefit of this technical modification remains to be proven.     

Anterior cruciate ligament reconstruction with preservation of remnant bundle using hamstring autograft: technical note

During an arthroscopic examination for an anterior cruciate ligament (ACL) reconstruction, there is a relatively thick remnant ACL tibial stump attached to the posterior cruciate ligament (PCL) or rarely remained between the femur origin and the tibia insertion. We thought that preservation of the remnant ACL original bundle might promote graft healing or be helpful in preserving the proprioception and function to stabilize the knee. Therefore, we established a remnant preservation procedure without additional instruments during an ACL reconstruction using a bio-cross pin (RIGIDfix system: Mitek, Johnson & Johnson, USA) for the femoral tunnel fixation. The remnant ACL was sutured (usually three stitches) using a suture hook (Linvatec, Largo, FL), and both ends of the sutures were pulled to the far anteromedial (AM) portal. These sutures protected the remnant tissue during the ACL reconstruction because medial traction of these sutures can provide a wide view during the reconstruction. After the femoral and tibial tunnel formation, these sutures were pulled out to the inferior sleeve of the cross pin using a previously inserted wire loop via an inferior sleeve. After graft passage, a superior cross pin was first fixed and tibial fixation was then performed. Finally, inferior cross pin fixation was performed and ties were made at the entrance of the inferior cross pin.     

Femoral Tunnel Drilling From the Anteromedial Portal Using the Figure-4 Position in ACL Reconstruction

Creation of the femoral tunnel in anterior cruciate ligament (ACL) reconstruction via the anteromedial portal can reproducibly achieve femoral tunnel positioning at the center of the femoral ACL footprint. Anteromedial portal drilling requires knee hyperflexion, which is awkward to perform. Knee hyperflexion to 120° can easily be achieved in the figure-4 position for femoral tunnel drilling via the anteromedial portal. The leg is hyperflexed in the figure-4 position on a Mayo stand. The offset femoral guide, guidewire, and drill are placed at the femoral ACL footprint via the anteromedial portal to create the femoral tunnel.     

移植物不同固定方式对自体腘绳肌腱重建膝前交叉韧带术后股骨骨道影响的对比研究

[目的]探讨自体腘绳肌腱重建膝前交叉韧带,移植物不同固定方式对术后股骨隧道的影响,与临床疗效关系。[方法]88例前交叉韧带损伤病例行关节镜下自体半腱肌、股薄肌腱重建前交叉韧带,根据移植物股骨侧固定方式不同,分为三组。A组26例,采用Endobutton固定;B组22例,采用可吸收挤压螺钉固定;C组40例,采用Rigidfix固定。术后平均随访16.5个月,进行MRI检查,测量矢状位骨道开口、开口1 cm、骨道最宽处三点骨道直径,以术后1周对应部位骨道直径为衡量标准,对其差值进行统计学分析。采用Lysholm评分评估各组临床疗效。[结果]3组病例前交叉韧带术后骨道直径均有不同程度增宽。在股骨侧骨道最宽处、开口1 cm处,3组测量结果两两对比有统计学差异(P0.05),B组增宽明显,C组骨道增宽最小;在股骨骨道开口处,C组骨道增宽程度最小(P0.05),A、B组无对比差异(P0.05)。A、C组股骨骨道形态呈线形;B组股骨骨道形态呈锥形。所有病例关节稳定性良好,无1例出现不稳。术后Lysholm评分,A组(94.4±2.9)分,B组(93.4±3.6)分,C组(96.3±2.7)分,三组间比较无显著差异(P0.05)。[结论]移植物固定方式影响前交叉韧带术后骨道扩大,是骨道扩大发生的重要因素;固定方式、骨道扩大程度与术后临床疗效无相关性。     

Anatomische vordere Kreuzbandersatzoperation mittels Semitendinosus- und Grazilissehne in fremdmaterialfreier Press-fit-Technik

An innovative technique for anterior cruciate ligament (ACL) reconstruction has been developed in 1998 which allows the grafts to be fixed by press-fit to the femoral and tibial tunnel without any hardware. The semitendinosus (ST) and gracilis tendons (GT) are built into a sling by tying a knot with the tendon ends and securing the knot after conditioning by sutures. For the femoral tunnel the anteromedial porta is used. The correct anatomic position of the single femoral tunnel is checked using intraoperative lateral fluoroscopy by placing the tip of a K-wire to a point between the anteromedial and posterolateral bundle insertion sites. A femoral bottleneck tunnel is drilled to receive the knot of the tendons. The tendon loops filled the tibial tunnel without any suture material. The loops are fixed at the tibial tunnel outlet with tapes over a bone bridge. Between 1998 and 1999 a prospective randomized study (level 1) was conducted comparing this technique with a technique using bone-patellar-tendon graft and press-fit fixation without hardware. In conclusion it was found that implant-free press-fit ACL reconstruction using bone-patella-tendon (BPT) and hamstring tendon (HT) grafts proved to be an excellent procedure to restore stability and function of the knee. Using hamstring tendons (ST and GT) significantly lower donor site morbidity was noted. Kneeling and knee walking pain persisted to be significantly more intense in the BPT up to 9 years after the operation. Re-rupture rates, subjective findings, knee stability and isokinetic testing showed similar results for both grafts. This is the first level I study which demonstrates cartilage protection by ACL reconstruction as long as the meniscus is intact at index surgery, shown by bilateral MRI analysis 9 years post-operation. There was no significant difference in the average grade of chondral and meniscus lesions between BPT and HT and in comparison of the operated to the intact knee, except for grade 3-4 lesions found at the 9 year follow-up, which were significantly higher in the BPT group.     

关节镜下半腱肌、股薄肌腱重建前交叉韧带

目的关节镜下以半腱肌、股薄肌腱重建膝前交叉韧带,分析影响疗效的因素。方法自2002年12月至2004年6月,关节镜下endobuttonl固定四股腘绳肌腱修复膝前交叉韧带损伤66例72膝。膝前小切口取半腱肌腱、股薄肌腱修整、对折后成四股,分别建立胫骨隧道及股骨隧道,用Endobutton和门形钉固定肌腱,重建ACL的解剖结构和生理功能。术后即行功能锻练。结果66例患者得到随访,随访时间13-30个月,平均22.25个月。术前Lachman征( ),术后Lachman征(-)。术前Lysholm评分从27分到71分,平均53.75分;术后Lysholm评分从70分到99分,平均90.83分,术前、术后评分有显著性差异(t=2.23,P<0.05)。结论腘绳肌腱具有良好的抗拉强度和刚度,在关节镜下用四股腘绳肌腱重建膝前交叉韧带是一种疗效可靠的治疗方式。     

Arthroscopic hamstring anteriorcruciate ligament reconstruction with endobutton femoral fixation

Numerous techniques of anterior cruciate ligament (ACL) reconstruction have been described in literature. All haveinherent advantages and disadvantages. Autogenous hamstring grafts provide adequate strength while avoiding donor site morbidity associated with bone-patellar tendon-bone harvest. Endobutton femoral fixation allows precise femoral tunnel placement without a second incision. This article describes our technique of endoscopie ACL reconstruction using a doubled semitendinosus autograft with Endobutton femoral fixation.     

Quadrupled bone-semitendinosus ACL reconstruction: a prospective clinical investigation in 100 patients

Abstract The hypothesis of our study was that a quadrupled bonesemitendinosus tendon graft could combine the advantage of bone-tobone healing with the high cross-sectional area of a quadrupled hamstring graft in ACL reconstruction. ACL reconstruction with a semitendinosus tendon graft was performed on 100 patients with isolated ACL injury from January 1996 to December 1999: femoral fixation was obtained with Endobutton and tibial fixation with Fastlok. Patients were evaluated for standard knee scores and functional strength tests, postoperative pain rating, knee radiographs taken after surgery and at final follow-up, magnetic resonance images at 3 and 6 months, isokinetic flexion-extension and internal-external rotation tests at 3, 6, and 12 months. Computerized laxity analysis was performed at final evaluation. Average surgical time was 85 minutes, including 13 minutes for graft preparation; 90% of the patients were discharged within 24 h. Subjective knee rating was 80%; kneeling test was positive in 7% and Werner score was 44 (range, 30–48). Lachman test was negative in 90% at final evaluation (mean follow-up, 38 months). Sensory changes at the anterior part of the proximal tibia were present in 30% at 3 months and 10% had definite hyposthesia. MRI showed graft incorporation at 3 months. Computerized laxity analysis revealed 90% with less than 3-mm side-to-side differences. Isokinetic testing showed normal hamstring and quadriceps peak torques at 12 months. The functional strength tests were normal by 6 months. Average Noyes score was 87.9, Lysholm score 93, and Tegner activity rating 6.0 (pre-injury, 6.1). IKDC score showed 90 normal or nearly normal knees, 9 abnormal, and one severely abnormal knee. Quadrupled bone-semitendinosus is a viable graft for ACL reconstruction and should be considered, especially in patients with pre-existing extensor mechanism problems.     

Oblique femoral tunnel or oblique graft? A modified anteromedial portal technique to obtain vertical femoral tunnel and oblique graft in anatomic anterior cruciate ligament reconstruction

In anterior cruciate ligament (ACL) reconstruction, transtibial drilling of the femoral tunnel has been criticized for its vertical and less anatomical tunnel, which accompanied rotational instability of knee. Many authors recommend anteromedial (AM) portal drilling technique, which creates more oblique and anatomic femoral tunnel. However, recent researches show that oblique tunnel is related to risks of too short femoral tunnel, blowout of back wall, and posterolateral structures injury. Is oblique femoral tunnel really essential for anatomic reconstruction? We introduce a modified AM technique, which abandons the oblique tunnel and provides vertical femoral tunnel and oblique graft with anatomic starting point. The fundamental of the new technique is that oblique graft but not oblique tunnel is essential for rotational stability of knee. Thus, it avoids the risks and preserves anatomic reproduction of ACL.     

Influence of three different fixation methods on femoral tunnel widening in ACL reconstructed patients evaluated using computed tomography (CT) scan

European Journal of Orthopaedic Surgery & Traumatology - To evaluate femoral tunnel widening in young and active patients undergoing ACL reconstruction with quadrupled hamstring graft with...     

前内侧入路解剖重建单束前交叉韧带的临床评估

目的评估关节镜下经前内侧入路解剖重建单束前交叉韧带(ACL)的位置、形态及临床效果。方法对25例ACL断裂患者在关节镜下经前内侧入路应用解剖重建技术行单束ACL重建术,移植物应用自体腘绳肌腱。术后行X线、MRI检查,了解骨道情况,观察移植物形态及张力,并与11例健侧膝关节的正常ACL进行对比。应用Lysholm评分系统评估膝关节功能。结果术后X线片显示股骨隧道内口位于髁间窝顶与股骨后缘皮质线交叉点前缘,胫骨隧道内口位于髁间窝顶后方。MRI显示所有重建ACL张力良好,ACL上倾角为50.82°±4.57°,胫骨平台止点至前缘距离与平台纵径比值为0.50±0.04,两项与对照组比较差异均无统计学意义(P0.05)。患者均获得随访,时间为13~44个月。Lysholm评分术后为92.20分±4.29分,明显高于术前的64.76分±7.16分(P0.01)。结论关节镜下经前内侧入路解剖重建ACL的位置及形态接近解剖结构,早中期临床效果满意。     

Isolierter Bündelersatz bei Partialruptur des vorderen Kreuzbandes

Objective

Partial augmentation of isolated tears of the anteromedial and posterolateral bundle of the anterior cruciate ligament (ACL) with autologous hamstring tendons. The intact fibers of the ACL are preserved.

Indications

Symptomatic isolated tear of the anteromedial or posteromedial bundle of the ACL or rotational instability after ACL reconstruction with malplaced tunnels (e.g., high femoral position)

Contraindications

In revision cases: loss of motion due to malplaced ACL and excessive tunnel widening of the present tunnels with the risk of tunnel confluence.

Surgical technique

Examination of anterior–posterior translation and rotational instability under anesthesia. Diagnostic arthroscopy, repetition of the clinical examination under direct visualization of the ACL, meticulous probing of the functional bundles. Resection of ligament remnants, preparation/preservation of the femoral and tibial footprint. Harvesting one of the hamstring tendons, graft preparation. Positioning of a 2.4 mm K-wire in the anatomic center of the femoral anteromedial/posterolateral bundle insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire balanced according to the femoral tunnel at the tibia, cannulated drilling. Insertion of the graft and fixation.

Postoperative management

Analogous to that for ACL reconstruction.     

Rekonstruktion des vorderen Kreuzbandes

The treatment of ruptures of the anterior cruciate ligament (ACL) plays an essential role for both clinicians and resident physicians. To date many questions regarding the outcome as well as ACL reconstruction techniques have not yet been conclusively clarified. Whether reconstruction of the ACL protects the knee from osteoarthritis is still unproven; however, it is well known that an unstable knee joint is more vulnerable to secondary injuries, such as meniscal tears. Thus, early ACL reconstruction is recommended to minimize the risk of these secondary injuries. Three alternative sources of material for autologous ACL reconstruction are commonly utilized. An accessory hamstring (i.e. semitendinosus tendon with or without the gracilis tendon), a central strip of the patellar tendon with bone blocks and a central strip of the quadriceps tendon with or without bone block are the most common donor tissues used in autografts. Besides selection of the type of graft, the tendon diameter also plays a crucial role. Some progress has recently been made with respect to tunnel placement. The aim is to find an anatomical tunnel position. Reconstruction of both the anteromedial and the posterolateral ACL bundles helps to rebuild the anatomy of the original ACL; however, scientifically this approach did not lead to any improvement in the results. For fixation techniques a differentiation is made between aperture, extracortical and implant-free fixation. Generally, re-ruptures are less common than revisions as a result of graft ruptures due to technical mistakes during surgery. The most common mistakes concern tunnel placement and graft fixation. Also overlooked instability can have a negative influence on the outcome of ACL reconstruction.     

In vitro comparison of elongation of the anterior cruciate ligament and single- and dual-tunnel anterior cruciate ligament reconstructions.

This study evaluated strain in the normal anterior cruciate ligament (ACL) and compared it to four different double-strand hamstring tendon reconstructive techniques. Seventeen fresh-frozen knees from 11 cadavers were tested. The strain in the anteromedial and posterolateral bands of the native ACL and their equivalents in four autograft techniques were measured using differential variable reluctance transducers. The anteromedial band of the intact ACL shortened from 0 degree -30 degrees of flexion, then lengthened to 120 degrees; the posterolateral band of the intact ACL shortened from 0 degree - 120 degrees of flexion. Following ACL excision, these knees underwent reconstruction with double-strand hamstring tendons with either single tibial and femoral tunnels, single tibial and dual femoral tunnels, dual tibial and single femoral tunnels, or dual tibial and dual femoral tunnels. With the exception of the dual-band, dual-tunnel technique, all of the procedures placed greater strain on the reconstructive tissues than was observed on the native ACL, after approximately 30 degrees of flexion. These results indicate that dual-band hamstring tendon reconstructions placed with single tibial and femoral tunnels do not address the complexity of the entire ACL. Rather, these procedures appear to only duplicate the effect of the anteromedial band, while perhaps overconstraining the joint as a result of its inability to reproduce the function of the posterolateral band. During rehabilitation following ACL reconstruction, therefore, only from 0 degree - 30 degrees of the graft tissues are not significantly strained. Dual tibial and femoral tunnel techniques should be evaluated further to more closely recreate knee kinematics following ACL reconstruction.