Anatomic Double-bundle Anterior Cruciate Ligament Reconstruction Research Articles

Tunnel Enlargement and Coalition After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts: A Computed Tomography Study.

Background:Tunnel enlargement and coalition following double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon autografts has not yet been sufficiently studied.Hypothesis:The incidence and the degree of femoral tunnel enlargement will be significantly greater than those for tibial tunnel enlargement after anatomic double-bundle ACL reconstruction using hamstring tendon autografts. There will be no significant correlation between tunnel enlargement and coalition and the postoperative knee laxity.Study Design:Case series; Level of evidence, 4.Methods:Thirty-nine patients who underwent anatomic double-bundle ACL reconstruction using semitendinosus and gracilis tendon autografts were followed up for 1 year after surgery. The grafts were simultaneously fixed at 10° of knee flexion with EndoButtons and spiked staples. All patients were examined with computed tomography and the standard clinical evaluation methods at 2 weeks and 1 year after surgery.Results:The degree of tunnel enlargement of the femoral anteromedial and posterolateral tunnels averaged 10% to 11% and 7% to 9%, respectively, while that of the tibial anteromedial and posterolateral tunnels averaged 3% to 7% and 1% to 6%. The degree and incidence of the anteromedial and posterolateral tunnel enlargement were significantly greater in the femur than in the tibia (P < .0335 and P < .0405, respectively). On the femoral and tibial intra-articular surface, tunnel outlet coalition was found in 5% and 77% of the knees, respectively, at 1 year after surgery. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.Conclusion:The incidence and the degree of each tunnel enlargement in the femur were significantly greater than that in the tibia. However, the incidence of tunnel coalition in the femur was significantly less than that in the tibia after double-bundle ACL reconstruction with a transtibial technique. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.Clinical Relevance:The present study provides orthopaedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Anatomic Anterior Cruciate Ligament Reconstruction: Current Concepts and Future Perspective.

Anatomic anterior cruciate ligament (ACL) reconstruction is common procedure performed by orthopedic surgeons, particularly in association with sports-related injuries. Whereas traditional reconstruction techniques used a single bundle graft that was typically placed in a non-anatomic position, a renewed interest in anatomy has facilitated the popularization of anatomic reconstruction techniques. Recently, a focus has been placed on individualizing ACL surgery based on each patient’s native anatomical characteristics (e.g., insertion site size, notch size, and shape), thereby dictating the ultimate procedure of choice. As subjective outcome measurements have demonstrated varying outcomes with respect to single- versus double-bundle ACL reconstruction, investigators have turned to more objective techniques, such as in vivo kinematics, as a means of evaluating joint motion and cartilage contact mechanics. Further investigation in this area may yield important information with regard to the potential progression to osteoarthritis after ACL reconstruction, including factors affecting or preventing it.

Anatomic Double-Bundle Reconstruction Techniques Result in Graft Obliquities That Closely Mimic the Native Anterior Cruciate Ligament Anatomy

Background: It has been reported previously that single-bundle anterior cruciate ligament (ACL) reconstruction with more accurate restoration of the footprint of the native ACL fails to restore the graft obliquity of the native ACL in the coronal plane. Whether double-bundle ACL reconstruction restores the graft obliquity of each bundle of the native ACL has not yet been determined. Hypothesis: Anatomic double-bundle ACL reconstruction using transportal (TP) and outside-in (OI) techniques can restore the graft obliquities of both anteromedial (AM) and posterolateral (PL) bundles in the native ACL in both sagittal and coronal planes. Study Design: Cohort study; Level of evidence, 2. Methods: Seventy-six patients underwent anatomic double-bundle ACL reconstruction. Patients were randomized to 2 groups to undergo either TP or OI tibial tunnel–independent anatomic ACL reconstruction. All participants underwent postoperative magnetic resonance imaging of both knees, and the native ACL obliquity was determined using the participant’s contralateral knee. Graft obliquities were determined by measuring the angles between the center line of the graft and the surface line of the tibial plateau, and the obliquities of paired knees were compared. Graft obliquities were analyzed in each group. Results: In the sagittal plane, the mean AM graft obliquity was 54.2° on the operated side and 54.6° on the nonoperated side, and the difference between sides was not statistically significant (P = .352). The mean PL graft obliquity in the sagittal plane was 54.1° on the operated side and 53.0° on the nonoperated side, and the difference between sides was also not statistically significant (P = .228). In the coronal plane, the mean AM graft obliquity was 73.8° on the operated side and 73.4° on the nonoperated side, and the mean PL graft obliquity was 65.5° on the operated side and 66.4° on the nonoperated side. There were no statistically significant differences between sides (P = .418 for AM graft; P = .328 for PL graft). Differences in the paired graft obliquities in each group were also statistically insignificant between the TP and OI groups. Conclusion: Both TP and OI anatomic double-bundle reconstruction techniques can result in graft obliquities in both bundles that resemble the native ACL in both sagittal and coronal planes. Clinical Relevance: Double-bundle ACL reconstruction techniques might more closely restore the normal kinematics of the native ACL by restoring the normal obliquity of both ACL bundles.

The Importance of Tibial Tunnel Placement in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

The purposes of this study were to measure the anterior edge of the tibial tunnel after anatomic anterior cruciate ligament (ACL) reconstruction on lateral radiographs and to determine whether the difference in tibial tunnel placement affects postoperative outcomes. For 60 patients who underwent anatomic double-bundle ACL reconstruction with semitendinosus tendon, we evaluated the side-to-side difference in anterior tibial translation on stress radiographs, as well as rotational stability by the pivot-shift test, 2 years after surgery. Loss of extension (LOE) was evaluated on lateral radiographs of both knees in full extension, and graft integrity was assessed during second-look arthroscopy 1 to 2 years after surgery. On true lateral radiographs, we measured the anterior placement percentage of the tibial tunnel using the method described by Amis and Jakob. The cutoff value was set at 25% of the mean value of the anterior edge of the ACL that Amis and Jakob reported, and patients were divided into 2 groups (27 in the anterior group and 33 in the posterior group). Postoperative clinical results were compared between the groups. The mean anterior placement percentage was 26.0% ± 4.1%. The postoperative mean side-to-side difference was 1.4 ± 2.7 mm for the anterior group and 3.0 ± 2.7 mm for the posterior group, a significant difference (P < .05). The positive ratio of the pivot-shift test was not significantly different between groups (P > .05). Mean LOE in the anterior and posterior groups was 0.9° ± 3.0° and -0.8° ± 4.0°, respectively; the difference was not significant (P > .05). Five of 27 knees in the anterior group and 5 of 33 knees in the posterior group had superficial graft laceration or elongation, which was not significantly different (P > .05). Anterior placement of the tibial tunnel in anatomic double-bundle ACL reconstruction leads to better anterior knee stability than posterior placement does. Anterior tibial tunnel placement inside the footprint did not increase the incidence of LOE and graft failure. Level IV, therapeutic case series.

The effect of cortical button location on its post-operative migration in anatomical double-bundle anterior cruciate ligament reconstruction

To investigate the effect of EndoButton (Smith & Nephew Endoscopy, Andover, MA, USA) location on post-operative migration in anterior cruciate ligament (ACL) reconstruction. Seventy-seven patients underwent anatomical double-bundle ACL reconstruction using EndoButtons. Comparing patient radiographs immediately post-operatively with those at 1 year, migration was defined when EndoButtons moved more than 1 mm or rotated over 5°. Initial location of EndoButtons was evaluated on radiographs immediately post-operatively. We measured distances from the EndoButton to the posterior and distal edge of the femur (D1, D2) on lateral radiographs and distances from the EndoButton to the lateral and distal edge of the femur (D3, D4) on anteroposterior radiographs. The relationship between supracondylar line and the ratio of migration was also investigated. D1 in the migrated group were significantly lower than those in the non-migrated group (11.8 ± 12.7 vs. 16.0 ± 10.2 mm). D2, D3 and D4 were not of significant difference in the two groups. The ratio of migration in the area posterior to the supracondylar line was significantly higher than that in the anterior area (54.3 vs. 15.1%). EndoButtons, which was located distally and posteriorly, especially in the area posterior to the lateral supracondylar line, migrated more frequently, although migration of the button had no effect on the clinical parameters evaluated in this study. It is preferable to settle EndoButton anteriorly to the lateral supracondylar line in order to avoid its migration for the graft tension due to our findings about the relationship between initial location of EndoButton and the rate of migration. Prognostic case series, Level IV.

Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

Over the past decade, intense research of the function of the 2 distinct bundles, the anteromedial and posterolateral, of the anterior cruciate ligament (ACL) has led to pronounced changes in the technical concepts of ACL reconstruction. Recently, the renewed focus of ACL reconstruction has been to restore the anatomy of the ACL to its native dimensions, collagen orientation, and insertion sites. The goal of ACL reconstruction is to restore normal knee kinematics, to enable patients to return to their preinjury level of activity, and to prevent further degenerative changes of the articular knee cartilage. Anatomic double-bundle ACL reconstruction has recently gained popularity as a concept that can be used to achieve these goals. This article provides an overview of the anatomy and function of the ACL. Furthermore, we highlight individual anatomic considerations as they pertain to ACL reconstruction and describe the technique for anatomical ACL reconstruction.

Prospective randomized comparison of anatomic single- and double-bundle anterior cruciate ligament reconstruction

To determine if anatomic double-bundle anterior cruciate ligament (ACL) reconstruction is superior to anatomic single-bundle reconstruction in restoring the stabilities and functions of the knee joint. A prospective randomized clinical study was done to compare the results of 32 cases of anatomic single-bundle ACL reconstruction and 34 cases of anatomic double-bundle ACL reconstruction with average follow-up of 16.3 ± 3.1 months. Tunnel placements of all the cases were measured on 3D CT. Clinical results were collected after reconstruction; graft's appearance, meniscus status and cartilage state under arthroscopy were compared and analysed too. Tunnel placements, confirmed with 3D CT, were in the anatomic positions as described in literature both in SB and DB group. No differences were found between SB and DB groups in clinical outcome scores, pivot shift test and KT 1000 measurements (average side-to-side difference for anterior tibial translation was 0.7 mm in SB group and 1.0 mm in DB group). More than 70 % of the single-bundle graft and AM bundle graft in DB group appeared excellent, but only 44.1 % of PL bundle grafts in DB group were excellent and 11.8 % were in poor state. No new menisci tear was found either in SB or DB group, however, in DB group cartilage damages in medial patella-femoral joint occurred in 38.2 % cases. This rate was significantly higher than in the SB group which is only 9.3 %. Both single- and double-bundle anatomic ACL reconstruction can restore the knee's stability and functions very well. However, more incidences of poor PL status and medial patellar-femoral cartilage damage may occur in double-bundle ACL reconstruction.

Application of a computerised navigation technique to assist arthroscopic anterior cruciate ligament reconstruction

Based on biomechanical cadaver studies, anatomical double-bundle reconstruction of the anterior cruciate ligament (ACL) was introduced to achieve better stability in the knee, particularly in respect of rotatory loads. Previously, the success of ACL reconstruction was believed to be mainly dependent on correct positioning of the graft, irrespective of the number of bundles for which computer-assisted surgery was developed to avoid malpositioning of the tunnel. The aim of this study was to compare rotational and translational stability after computer-navigated standard single-bundle and anatomical double-bundle ACL reconstruction. The authors investigated 42 consecutive patients who had undergone the single-bundle or double-bundle ACL reconstruction procedure using autogenous hamstring tendon grafts and ENDOBUTTON fixation in patients who had been followed up for a minimum of 24 months. Post-operative anteroposterior and rotational laxity was measured with the KT3000 and compared between groups. Both surgical procedures significantly improve rotational and translational stability compared to the preoperative ACL-deficient knee (P<0.05). No significant differences were registered between groups with regard to anteroposterior displacement of the tibia. The International Knee Documentation Committee (IKDC) and Lysholm scores were significantly higher in the double-bundle group. However, the results were excellent in both groups. The use of computer-assisted ACL reconstruction, which is a highly accurate method of graft placement, could be useful for inexperienced surgeons to avoid malposition. Long-term results of at least five years are needed to determine whether double-bundle ACL reconstruction, which was associated with improved rotational laxity and significantly better IKDC and Lysholm scores compared to the standard single-bundle ACL reconstruction procedure, exerts an influence in terms of avoiding osteoarthritis or meniscus degeneration.

Comparison of Tunnel Orientation Between Transtibial and Anteromedial Portal Techniques for Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Computed Tomography

The aim of this study was to compare femoral and tibial tunnel placement, angle, and length between transtibial and anteromedial portal techniques for anatomic double-bundle anterior cruciate ligament (ACL) reconstruction. Fifty patients were randomized to the 2 groups, and a femoral tunnel was created through the tibial tunnel (transtibial) and the far anteromedial portal (AMP) in 25 patients each. Both groups underwent anatomic double-bundle ACL reconstruction with hamstring tendons. Volume-rendering computed tomography (CT) was used to evaluate femoral and tibial tunnel placement, and transparent 3-dimensional CT image reconstruction, to evaluate tunnel angles, on the seventh postoperative day. Femoral tunnel length was measured intraoperatively. Anteromedial bundle (AMB) and posterolateral bundle (PLB) femoral tunnels were placed significantly lower and deeper with the AMP technique (shallow/deep direction: 21% and 30%, high/low direction: 18% and 48%) than with the transtibial technique (25% and 34%, 12% and 43%). Except for the tibial tunnel angle in the axial plane, AMB and PLB femoral and tibial tunnel angles differed significantly in 3 dimensions. AMB and PLB femoral tunnel lengths were significantly shorter with the AMP technique (AMB: 33 mm, PLB: 32 mm) than with the transtibial technique (AMB: 49 mm, PLB: 37 mm) (P < .001 and P=.001). Both femoral tunnel lengths in the AMP group correlated significantly with the tunnel angle in the sagittal (AMB: r= 0.69, PLB: r= 0.51) and axial (AMB: r= 0.58, PLB: r= 0.75) planes. AMB and PLB femoral tunnels were placed significantly deeper, lower, and closer to the femoral footprint reported in previous cadaveric studies in the anteromedial portal technique than in the transtibial technique. Femoral tunnel length was significantly shorter in the anteromedial portal group than in the transtibial group. Level II, prospective comparative study.

Femoral Graft Bending Angle and Femoral Tunnel Geometry of Transportal and Outside-In Techniques in Anterior Cruciate Ligament Reconstruction: An In Vivo 3-Dimensional Computed Tomography Analysis

To compare femoral graft bending angles and femoral tunnel geometries between the transportal (TP) and outside-in (OI) techniques after anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. Thirty-nine patients underwent DB ACL reconstruction with the TP and OI techniques. They were randomized on the day of surgery to either the TP group (group I, 21 cases) or the OI group (group II, 18 cases). Femoral graft bending angle, femoral tunnel geometry, posterior wall breakage, and tunnel communication were assessed by computed tomography imaging with OsiriX imaging software (Pixmeo, Geneva, Switzerland). The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angles of group II (97.3° ± 8.3° and 97.4° ± 8.6°, respectively) were significantly more acute than those of group I (108.2° ± 8.4° and 109.9° ± 8.8°, respectively) (P < .001). The mean AM femoral tunnel length of group II (34.3 ± 3.9 mm) was significantly longer than that of group I (31.9 ± 2.7 mm) (P = .02). However, the mean PL femoral tunnel lengths did not differ between groups. In 7 cases-4 cases (19.0%) in group I and 3 cases (16.6%) in group II-the femoral tunnel communication was found around the intra-articular aperture. Posterior wall breakage was observed in 5 cases (23.8%), which were all in AM femoral tunnels of group I. The OI technique resulted in more acute femoral graft bending angles (difference of 10.9° and 12.5° for AM and PL, respectively) and longer mean AM femoral tunnel lengths (difference of 2.4 mm) than the TP technique after anatomic DB ACL reconstruction, even though these small differences might be unlikely to be of clinical significance. Femoral tunnel communication was found in both groups, and posterior wall breakage was observed in AM femoral tunnels with the TP technique. Level I, prospective randomized trial.

Anatomic double-bundle ACL reconstruction restricts knee extension in knees with hyperextension

Double-bundle ACL reconstruction has been demonstrated to be at least as effective as single-bundle reconstruction in terms of restoring knee rotational and translational stability. Until now, the influence on knees with hyperextension has not been evaluated. It was the purpose of this study to evaluate whether double-bundle ACL reconstruction restricts extension in hyperextendable knees. Hamstring tendon reconstructions of 10 human cadaveric knees with the ability of hyperextension (age: 48±14years) were performed as single bundle (SB) on one side and double bundle (DB) on the other side. A surgical navigation system (BrainLab, Germany) was used to assess the kinematics of each knee at the intact and reconstructed state. A difference with regard to the anterior-to-posterior translation (AP) and rotational stability at 30° of knee flexion, 90° of flexion and the hyperextension capability of each specimen was analysed. The difference in AP translation before and after the reconstruction was not significantly different in 30° and 90° of flexion (n.s). Both single- and double-bundle reconstructions restored the preoperative kinematics at 30° and 90° of knee flexion (n.s). The knee extension was 4°±1.8° with the intact ACL and 4°±1.7° after reconstruction in the SB group (n.s). The knee extension was 5° of hyperextension±1.1° with the intact ACL and 0°±0.4° after reconstruction in the DB group; the limitation of the extension was significantly larger in this group (p=0.013). Both single- and double-bundle ACL reconstruction techniques are capable of restoring knee anteroposterior and rotational stability. Double-bundle reconstructions significantly reduce knee extension in knees with hyperextension capability. Care must be taken when using double-bundle techniques in patients with knee hyperextension as this procedure may limit the knee extension after double-bundle ACL reconstruction.

Paper 208: The Use of 3-D CT Scan to Validate the Position of the Femoral Tunnels in Anatomic Double-bundle ACL Reconstruction

The success of anatomic double-bundle ACL reconstruction is strongly related to tunnel positioning. Quantification and validation of tunnel location is still subject to debate. We performed a clinical study for evaluating the positioning of femoral anteromedial (AM) and posterolateral (PL) tunnels following anatomic double-bundle ACL reconstruction using high-speed 3-D computed tomography (3-D CT). We hypothesize that the position of the tunnels drilled with a specifically designed aimer will be located within the native ACL femoral footprint limits. case controlled series anatomic double-bundle ACL reconstruction with hamstrings tendons was performed with the Anatomic Director instruments set. During surgery the centre of each bundle was marked with a thermal probe. After drilling the AM tunnel through the AM portal, the PL tunnel was drilled with a specific PL aimer inserted through a far medial portal in the previously drilled AM tunnel. Thirty five continuous patients were enrolled in the study and prospectively evaluated with high speed 3-D CT scan performed within 1–3 days following surgery. Three-D reconstructions of both intact and involved knees were performed using the volume rendering technique, with the contralateral knee as control. In the control group, we measured the angle formed between the resident's ridge -which is parallel to the longitudinal axis of the ACL footprint- and the axis of the femoral diaphysis, named the “footprint angle” (FA) and the angle formed between the ridge and the Blumensaat's line (FB). On the involved side, using the axis passing through the centres of both tunnels as a reference line, FA and FB angles were also measured. The AP- and proximo-distal diameters of the ACL attachment area were measured. Also, in the involved side, the distances of ACL from the anterior, posterior and distal cartilage borders were measured and compared with the results of anatomical studies available in the literature. Finally, the distance from the centres and the bone bridge between the tunnels were also measured. the morphometric data for the involved group were the following: FA 31.4° ± 15.2°, FB 67.0° ± 16.9°, AP footprint diameter (mm) 17.2 ± 2.1, proximo distal diameter 8.1 ± 0.9, distances to cartilage (mm), posterior 2.2 ± 1.6, anterior 1.1 ± 0.7, distal 2.7 ± 1.2, distance between AM and PL bundle centres (mm) 9.4 ± 1.2. For the control group, FA 26.5° ± 4.7°, FB 61.6° ± 6.8°, AP footprint diameter (mm) 17.3 ± 1.7, proximo distal diameter 8.8 ± 1, distances to cartilage (mm), posterior 2.5 ± 1.1, anterior 1.8 ± 1.3, distal 2.8 ± 1.5, distance between AM and PL bundle centres (mm) 8.2 ± 1.2. There was no significant difference between the different values of the two groups. The native and reconstructed footprints were always entirely located distal to the resident's ridge. A highly significant correlation was found between FA and FB in both control (r = 0.71) and involved (r = 0.9) groups. The bone bridge thickness between the tunnels was 2.9mm ± 1.1mm. the morphometry of the femoral footprint of the ACL can be quantified using both its orientation and distances with regard to the local anatomical bony ridges, and cartilage borders landmarks. Locating the tunnels within the ACL footprint limits with appropriate restoration of the angle between the long axis of the femur and the long axis of the ACL femoral footprint are appropriate criteria to validate the proper positioning of the femoral tunnels when an anatomic double-bundle ACL reconstruction is performed. The use of a specifically-designed posterolateral femoral aimer allows duplicating the true morphometry of the native ACL footprint. Finally, as FA and FB are highly correlated, it is possible to use FB only to validate the footprint orientation on regular X-ray lateral view.

Paper 153: Intra-operative Three-dimensional Imaging Based Navigation Assisted Anatomic Double-Bundle ACL reconstruction

In anatomic double-bundle ACL reconstruction, it is technically demanding even for experienced surgeons to place two femoral tunnels within ACL attachment. We describe a technique using three-dimensional (3D) fluoroscopy-based navigation system to place two femoral tunnels accurately during anatomic double-bundle ACL reconstruction. After a reference frame is rigidly attached to a femur, intra-operative 3D image of the distal femur was obtained with C-arm of Arcadis Orbic (Siemens, Germany). The image was transferred to a navigation system (StealthStation navigation system, Medtronic, Louisville, CO) and reconstructed into a 3D image of the distal femur.

Paper 209: Effects of Initial Graft Tension on Clinical Outcome After Anatomic Double-bundle Anterior Cruciate Ligament Reconstruction: Comparisons Among Three Tensioning Techniques

Graft tensioning is one of the important factors that influence the clinical outcome of anterior cruciate ligament (ACL) reconstruction. The effect of initial graft tension on the clinical results of single-bundle ACL reconstruction has been studied by several studies. However, no studies have clarified the effect of initial graft tension on the clinical outcome after anatomic double-bundle ACL reconstruction. We have developed the first procedure for anatomic double-bundle ACL reconstruction (Arthroscopy 2004), and evaluated the clinical results (Arthroscopy 2006, AJSM 2008).

Paper 123: Bundle Augmentation in Chronic Partial ACL Tears

based on the concept of anatomic double bundle ACL reconstruction it has been proposed to augment partial tears of the ACL by reconstructing the missing bundle. There are few data available in the literature on the outcome of such reconstructive surgery. This retrospective study has been undertaken to evaluate the results of such a strategy in the treatment of chronic (>3 months) tear of the ACL.

Paper 154: Navigation Evaluation of Pivot Shift During Anatomical Double-bundle ACL Reconstruction

Paper 154: Navigation Evaluation of Pivot Shift During Anatomical Double-bundle ACL Reconstruction

Paper 207: Postoperative Evaluation of Tunnel Position by Radiography in Anatomic Double-Bundle ACL Reconstruction: Correlation with Clinical Results

Double-bundle ACL reconstruction has been proposed to restore normal anatomy and kinematics of the knee, however non-anatomic tunnel placement may lead to less than optimal clinical outcomes. The purpose of this study was to determine the relationship between tunnel placement and clinical outcomes following double-bundle ACL reconstruction. Anatomic tunnel placement will be related to better clinical outcomes. Methods: The tunnel positions for 67 subjects that underwent double-bundle ACL reconstruction were measured on post-operative radiographs. Forty males and 27 females were included in this study. Their average age was 27.39 ± 11.04 years and the average length of follow-up was 2.07 ± 0.52 years. Femoral length was measured as the distance from the most posterior contour of the lateral femoral condyle parallel to Blumensaat's line and femoral height was measured as the perpendicular distance from Blumensaat's line. Tibial depth was measured as the distance from the most anterior aspect of the tibia on the sagittal view and tibial width was measured as the distance from the medial tibial plateau on the AP view. All measurements of tunnel position were normalized to express the position as the percentage of medial-lateral and anterior-posterior distance on the tibial plateau and the proximal-distal and anterior-posterior position on the femoral condyle. The relationships between tunnel position and clinical outcomes including range of motion, manual and instrumented laxity and patient-reported outcome were analyzed. On average, the center of the femoral AM insertion of the ACL was located at 26.3% of the femoral length and at 17.6% of the femoral height. The center of the femoral PL insertion was located at 40.2% of the femoral length and 40.8% of the femoral height. The center of the tibial AM and PL insertions were located at 34.8% and 52.6% of the AP tibial length and at 43.2% and 47.2% of the tibial width, respectively. A higher and more anterior position of the AM femoral tunnel was associated with a greater perception of instability. Lower position of the PL femoral tunnel was associated with higher Activities of Daily Living Scores. More posterior placement of the AM tibial tunnels was associated with a greater KT-1000 side to side difference. Our results indicate that placing the AM and PL femoral tunnels closer to their anatomic insertion sites leads to improved clinical outcomes. The results also suggest that more anatomic placement of the AM tibial tunnel better restores normal AP knee laxity.

Restoration of sagittal and transverse plane proprioception following anatomic double-bundle ACL reconstruction

To investigate the restoration of knee proprioception after anatomic double-bundle ACL reconstruction. Eleven subjects who underwent anatomic double-bundle ACL reconstruction (12.5-15months following surgery) and eleven healthy control subjects participated in the study. Sagittal and transverse plane threshold to detect passive motion (TTDPM) were assessed utilizing a customized isokinetic dynamometer by passively rotating the tibia about a fixed femur in both the sagittal plane and transverse plane at 0.25°/s until the subject signalled recognition of movement and movement direction. Based on the normality assumption, either dependent t test or Wilcoxon test was utilized to determine whether significant differences were present between the ACL-reconstructed and the uninjured contralateral limbs. Independent t test or Mann-Whitney test was utilized to compare between the ACL-reconstructed/uninjured contralateral and the external control limbs. There were no significant differences in TTDPM measurement in eleven out of twelve comparisons between the ACL-reconstructed and the uninjured contralateral/external control limbs. The only statistical significant difference was found on TTDPM towards internal rotation direction from the externally rotated-test position between the ACL-reconstructed and the uninjured contralateral limbs (p=0.01). Based on a small sample of eleven subjects, the current results indicate a restoration of both sagittal and transverse plane TTDPM following the anatomic double-bundle ACL reconstruction. III.

The footprint of femoral insertion of anterior cruciate ligament three-dimensionally reconstructed by dual-source CT

Objective To measure the double-bundle footprints of the anterior cruciate ligament (ACL) three-dimensionally reconstructed by dual-source three-dimensional computed tomography (DSCT) so as to provide parameters for anatomic double-bundle ACL reconstruction in clinic.Methods This study enrolled 55 healthy volunteers,32 men and 23 women,20 to 50 years of age (average,28 years).One hundred and ten knees were scanned and processed with 64-slice spiral CT workstation (GE,Volume Share2-AW 4.4 version).The lateral wall of the intercondylar notch and the ACL femoral footprint were reconstructed three-dimensionally.The angle,length and width of the footprint,the distance between the double-bundle centers (DDBC) (anteromedial bundle and posterolateral bundle),and the distance from the footprint edge to the margin of the articular cartilage were measured.Results In this serial,the footprint angle averaged 6.8° ± 4.6°,the long footprint axis 16.8 ± 1.7 mm,the short footprint axis 7.5 ± 1.4 mm,DPCM 1.9 ± 1.0 mm,DDCM 1.5 ± 1.3 mm,and DDBC 8.0 ± 1.0 mm.There were no significant differences concerning footprint angle,long footprint axis,short footprint axis,DPCM,DDCM and DDBC between the left and the right knees in men and in women ( P ＞ 0.05) except concerning DPCM between the left and the right knees in women ( P ＜ 0.05).There were no significant differences concerning footprint angle and short footprint axis between men and women (P＞ 0.05),but there were significant differences concerning long footprint axis,DPCM,DDCM and DDBC between men and women ( P ＜ 0.05).Conclusions Measurements of femoral ACL footprints by DSCT reconstruction in normal population are reliable and representative.The footprint angle,DDBC and the distance from the footprint edge to the margin of the articular cartilage vary from individual to individual. Key words: Anterior cruciate ligament; Femur; Tomography; spiral computed

“Figure 8” Single Socket Double Bundle ACL Technique

Using single femoral and tibial tunnels, we describe a technique of anatomically recreating the anteromedial and posterolateral anterior cruciate ligament (ACL) bundles. Transtibial, flexible reamers are utilized to create a "Figure 8" notched tunnel thereby recreating the anatomic footprint of the femoral insertion of the ACL. Rotational control of the individual bundles is created via the notched tunnel and each bundle is tensioned to 80 N individually. Anatomic double bundle ACL reconstruction is created in a reproducible modified single-bundle technique without the inherent risks associated with drilling four tunnels.