Search

Background: Research on factors influencing the outcomes of revision anterior cruciate ligament (ACL) reconstruction is relatively scarce and mostly relies even on reports from a single group. Understanding the factors contributing to the failure of revision ACL reconstruction can provide valuable information for achieving better clinical outcomes and assist in patient counseling before surgery. Therefore, this study aimed to analyze the factors contributing to surgical failure after revision ACL reconstruction. Methods: The medical records of consecutive patients who underwent single-bundle revision ACL reconstruction using the transportal technique between 2010 and 2020 and had a minimum follow-up of 2 years were retrospectively reviewed. Eligible patients were classified into two groups on the basis of the presence of surgical failure during the follow-up period (group NF, patients who did not experience surgical failure; group F, patients who experienced surgical failure). In this study, surgical failure after revision ACL reconstruction was defined as meeting any of the following conditions during follow-up: the presence of graft re-tear confirmed by magnetic resonance imaging (MRI), anterior–posterior laxity graded ≥ 2, or rotational laxity graded ≥ 2. A comparative analysis was conducted on demographic data, as well as peri-, intra-, and postoperative data between the groups. Additionally, a regression analysis was performed to investigate factors influencing surgical failure after revision ACL reconstruction. Results: A total of 58 patients were included (group NF, 40 patients; group F, 18 patients). In between-group comparisons of demographic, peri-, and intra-operative data, group F exhibited a higher frequency of multiple revision surgeries (P = 0.001), increased preoperative osteoarthritis grade (P = 0.001), and shallower femoral tunnel depth (P = 0.002) compared with group NF. At the final follow-up, group F demonstrated relatively poor clinical outcomes, both subjectively and objectively. Multivariate regression analysis revealed that all variables that showed differences in the preceding comparisons were independent factors affecting surgical failure after revision ACL reconstruction. Conclusions: Surgical failure after revision ACL reconstruction can occur in a substantial number of patients, influenced by non-modifiable factors, such as cases corresponding to multiple revision surgery and preoperative osteoarthritis grade, and modifiable factors, such as femoral tunnel depth. [ABSTRACT FROM AUTHOR]

Purpose: To determine the optimal angles for independent femoral tunnel drillings in single-bundle anterior cruciate ligament reconstruction (ACLR) in different races and genders with the aim of preventing damage to lateral femoral anatomic structures (LFAS), posterior cortex and medial femoral condyle. Methods: This study included 180 volunteers, including 90 Caucasian and 90 matched Chinese. Magnetic resonance imaging (MRI) was used to scan the knees to create three-dimensional bone models, the ACL femoral footprint centre and the LFAS. In each femur model, femoral tunnels were established using a set of 16 distinct angular combinations: 15°, 30°, 45°, and 60° in the axial plane, as well as 15°, 30°, 45°, and 60° in the coronal plane. The minimum distance from the tunnel exit to the LFAS was evaluated, and the tunnel length, posterior cortex damage and medial femoral condyle injury were assessed. Results: Among the 180 patients with simulated ACL femoral tunnels, there was damage to the anatomical structure in parts of the model. According to the Cochran Q test results (P < 0.001), the percentage of safe tunnels varied significantly among the 16 different drilling angle combinations. The overall occurrence of the tunnel exit causing injury to LFAS were 8.3% and 8.1% in Chinese and Caucasian groups (P = 0.786). The means for tunnel length in Caucasians was 40.1 ± 7.9 mm, respectively; for Chinese, the results was 38.8 ± 6.6 mm (P < 0.001). Females had significantly shorter femoral tunnels than males in both Chinese and Caucasian (P < 0.001). The overall invasion rate of the posterior cortex and medial femoral condyle were 32.6% and 7.4% for Chinese; 31.0% and 7.4% for Caucasians, respectively. Conclusion: To reduce risks of injury to anatomical structures, such as the LFAS, posterior cortex and medial femoral condyle, specific angle combinations of 30°/45°, 45°/30°, 45°/45°, 45°/60°, 60°/30°, 60°/45° and 60°/60° should be used when creating the femoral tunnel in single-bundle ACLR. The selected drilling angles are critical for optimizing femoral tunnel placement. [ABSTRACT FROM AUTHOR]

Purpose: To compare the anterior and posterior trans-septal (TS) portal approaches in anterior cruciate ligament reconstruction (ACLR) by evaluating femoral tunnel positioning and passive anterior tibial subluxation (PATS). Methods: A total of 205 patients who underwent primary ACLR using the outside-in technique between March 2018 and December 2021 were retrospectively enrolled. Patients were classified into two groups based on the viewing techniques: the anterior group was treated using anteromedial or anterolateral portals (n = 155), and the TS group was treated using posterior TS portal (n = 55). The relative locations of the femoral tunnel were evaluated using the deep-shallow planes (X-axis) and superior-inferior planes (Y-axis) with the quadrant method in the lateral femoral condyle on a 3-dimensional computed tomography image. Anterior tibial subluxation for the lateral and medial compartments relative to the femoral condyles was evaluated as measured on magnetic resonance imaging. Knee laxity was assessed using the pivot-shift test and stress radiography. Results: In the posterior TS group, the femoral tunnel was usually located deeper on the X-axis and more superior on the Y-axis, which corresponds to a more proximal position, than in the anterior group (deeper on the X-axis and superior on the Y-axis). Moreover, the femoral tunnel locations in this group were more compactly distributed than those in the anterior group. The TS group showed significantly better reduction of postoperative PATS in the lateral compartments than the anterior group (anterior group vs. TS group: lateral compartment, 3.2 ± 3.1 vs. 4.5 ± 3.2 mm; p =.016). Significantly better results were found in the TS group for knee stability as assessed by the pivot-shift grade (p =.044); however, there were no significant differences between the two groups with respect to patient-reported outcome measures (p >.05) and other complications (p =.090). Conclusion: Our results suggest that positioning the femoral tunnel using the posterior TS portal approach may lead to better outcomes in terms of PATS and rotational stability compared to the anterior portal approach in ACLR. [ABSTRACT FROM AUTHOR]

Abstract Background Research on factors influencing the outcomes of revision anterior cruciate ligament (ACL) reconstruction is relatively scarce and mostly relies even on reports from a single group. Understanding the factors contributing to the failure of revision ACL reconstruction can provide valuable information for achieving better clinical outcomes and assist in patient counseling before surgery. Therefore, this study aimed to analyze the factors contributing to surgical failure after revision ACL reconstruction. Methods The medical records of consecutive patients who underwent single-bundle revision ACL reconstruction using the transportal technique between 2010 and 2020 and had a minimum follow-up of 2 years were retrospectively reviewed. Eligible patients were classified into two groups on the basis of the presence of surgical failure during the follow-up period (group NF, patients who did not experience surgical failure; group F, patients who experienced surgical failure). In this study, surgical failure after revision ACL reconstruction was defined as meeting any of the following conditions during follow-up: the presence of graft re-tear confirmed by magnetic resonance imaging (MRI), anterior–posterior laxity graded ≥ 2, or rotational laxity graded ≥ 2. A comparative analysis was conducted on demographic data, as well as peri-, intra-, and postoperative data between the groups. Additionally, a regression analysis was performed to investigate factors influencing surgical failure after revision ACL reconstruction. Results A total of 58 patients were included (group NF, 40 patients; group F, 18 patients). In between-group comparisons of demographic, peri-, and intra-operative data, group F exhibited a higher frequency of multiple revision surgeries (P = 0.001), increased preoperative osteoarthritis grade (P = 0.001), and shallower femoral tunnel depth (P = 0.002) compared with group NF. At the final follow-up, group F demonstrated relatively poor clinical outcomes, both subjectively and objectively. Multivariate regression analysis revealed that all variables that showed differences in the preceding comparisons were independent factors affecting surgical failure after revision ACL reconstruction. Conclusions Surgical failure after revision ACL reconstruction can occur in a substantial number of patients, influenced by non-modifiable factors, such as cases corresponding to multiple revision surgery and preoperative osteoarthritis grade, and modifiable factors, such as femoral tunnel depth.

Abstract Purpose To determine the optimal angles for independent femoral tunnel drillings in single-bundle anterior cruciate ligament reconstruction (ACLR) in different races and genders with the aim of preventing damage to lateral femoral anatomic structures (LFAS), posterior cortex and medial femoral condyle. Methods This study included 180 volunteers, including 90 Caucasian and 90 matched Chinese. Magnetic resonance imaging (MRI) was used to scan the knees to create three-dimensional bone models, the ACL femoral footprint centre and the LFAS. In each femur model, femoral tunnels were established using a set of 16 distinct angular combinations: 15°, 30°, 45°, and 60° in the axial plane, as well as 15°, 30°, 45°, and 60° in the coronal plane. The minimum distance from the tunnel exit to the LFAS was evaluated, and the tunnel length, posterior cortex damage and medial femoral condyle injury were assessed. Results Among the 180 patients with simulated ACL femoral tunnels, there was damage to the anatomical structure in parts of the model. According to the Cochran Q test results (P

Abstract Background The positioning error of femoral tunnel was the key factor leading to the failure of anterior cruciate ligament (ACL) reconstruction. This study aimed to propose a new femoral tunnel classification to guide revision ACL reconstruction. Methods Totals of 150 patients with ACL reconstruction failure from 2017 to 2023 were enrolled in this retrospective study. According to the tunnel diameter, shape, posterior wall and the positioning relationship with the Lateral Intercondylar Ridge on the three-dimensional CT imaging, we divided the femoral tunnels into four types: Type I off-target type, Type II straddled type, Type III anatomical type, and Type IV irregular type. Finally, explored the inter-observer reliability within two groups of doctors (Group A, 12 high seniorities; Group B, 12 low seniorities), and evaluated the intra-observer reliability within 6 doctors after two months. Clinical evaluation was performed using the Lysholm score, Tenger activity score, Pivot Shift and anterior knee laxity measurements. Results Among 150 cases of femoral tunnel three-dimensional CT reconstructed imaging, 144 cases were successfully included in the classification system, and 6 cases were confirmed as uncertain type. We measured the Kappa (κ) coefficient of group A was significantly higher than that of group B (κ 0.72 VS 0.68), and the κ coefficient of group A was still higher than group B (κ 0.69 VS 0.62) after further dividing Type III anatomical type into three subtypes. In addition, the κ coefficients of intra-observer reliability were all exceeded 0.73. Clinical follow-up showed that 9 patients had good knee joint motor function and stability after operation. Conclusion The new femoral tunnel classification was reliable and had clinical guiding significance based on three-dimensional CT imaging. Level of evidence Level III.

Background: The positioning error of femoral tunnel was the key factor leading to the failure of anterior cruciate ligament (ACL) reconstruction. This study aimed to propose a new femoral tunnel classification to guide revision ACL reconstruction. Methods: Totals of 150 patients with ACL reconstruction failure from 2017 to 2023 were enrolled in this retrospective study. According to the tunnel diameter, shape, posterior wall and the positioning relationship with the Lateral Intercondylar Ridge on the three-dimensional CT imaging, we divided the femoral tunnels into four types: Type I off-target type, Type II straddled type, Type III anatomical type, and Type IV irregular type. Finally, explored the inter-observer reliability within two groups of doctors (Group A, 12 high seniorities; Group B, 12 low seniorities), and evaluated the intra-observer reliability within 6 doctors after two months. Clinical evaluation was performed using the Lysholm score, Tenger activity score, Pivot Shift and anterior knee laxity measurements. Results: Among 150 cases of femoral tunnel three-dimensional CT reconstructed imaging, 144 cases were successfully included in the classification system, and 6 cases were confirmed as uncertain type. We measured the Kappa (κ) coefficient of group A was significantly higher than that of group B (κ 0.72 VS 0.68), and the κ coefficient of group A was still higher than group B (κ 0.69 VS 0.62) after further dividing Type III anatomical type into three subtypes. In addition, the κ coefficients of intra-observer reliability were all exceeded 0.73. Clinical follow-up showed that 9 patients had good knee joint motor function and stability after operation. Conclusion: The new femoral tunnel classification was reliable and had clinical guiding significance based on three-dimensional CT imaging. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: The success of medial patellofemoral ligament (MPFL) reconstruction is closely linked to the precise positioning of the femoral tunnel. Intraoperative fluoroscopy is commonly utilized to identify the MPFL footprint. This study aimed to ascertain the most accurate fluoroscopic method among the five previously described methods used to determine the MPFL femoral footprint. Materials and methods: Using 44 well-preserved dry femur bones, the MPFL femoral insertion site was demarcated using anatomical bony landmarks, namely the center of the saddle sulcus between the medial epicondyle, adductor tubercle and gastrocnemius tubercle. Fluoroscopic true lateral knee images were acquired and measurements taken, referencing established methods by Schottle et al., Redfern et al., Wijdicks et al., Barnett et al., and Kaipel et al. The distance between anatomic and fluoroscopic MPFL footprints was then measured on digital fluoroscopic images. The accuracy of the locations was compared using a margin of error of 5 and 7 mm. Results: The Schottle method consistently emerged superior, showcasing the smallest mean distance (3.2 ± 1.2 mm) between the anatomic and radiographic MPFL footprints and a high in-point detection rate of 90.9% under 5 mm criteria. While the Redfern method displayed perfect accuracy (100%) within the 7 mm criteria, the Schottle method also performed 97.7% accuracy. Conclusions: For intraoperative identification of the MPFL footprint using fluoroscopy, the Schottle method is the most consistent and accurate among the assessed methods. Thus, its accuracy in detecting the MPFL footprint makes it recommended for MPFLR to ensure optimal outcomes. Level of evidence: Level IV, cadaveric study. [ABSTRACT FROM AUTHOR]

Introduction: Accurate positioning of the femoral tunnel in ACL reconstruction is of the utmost importance to reduce the risk of graft failure. Limited visibility during arthroscopy and a wide anatomical variance attribute to femoral tunnel malposition using conventional surgical techniques. The purpose of this study was to determine whether a patient specific 3D printed surgical guide allows for in vitro femoral tunnel positioning within 2 mm of the planned tunnel position. Materials and Methods: A patient specific guide for femoral tunnel positioning in ACL reconstruction was created for four human cadaveric knee specimens based on routine clinical MRI data. Fitting properties were judged by two orthopedic surgeons. MRI scanning was performed both pre- and post-procedure. The planned tunnel endpoint was compared to the actual drilled femoral tunnel. Results: This patient specific 3D printed guide showed a mean deviation of 5.0 mm from the center of the planned femoral ACL origin. Conclusion: In search to improve accuracy and consistency of femoral tunnel positioning in ACL reconstruction, the use of a patient specific 3D printed surgical guide is a viable option to explore further. The results are comparable to those of conventional techniques; however, further design improvements are necessary to improve accuracy and enhance reproducibility. [ABSTRACT FROM AUTHOR]

Abstract Background Portal positioning in arthroscopic anterior cruciate ligament reconstruction is critical in facilitating the drilling of the femoral tunnel. However, the traditional approach has limitations. A modified inferior anteromedial portal was developed. Therefore, this study aims to compare the modified and conventional far anteromedial portals for femoral tunnel drilling, assessing factors such as tunnel length, inclination, iatrogenic chondral injury risk, and blowout. Material and methods Patients scheduled for hamstring autograft-based anatomical single-bundle arthroscopic anterior cruciate ligament reconstruction were divided into two groups: modified and far anteromedial groups. Primary outcomes include differences in femoral tunnel length intraoperatively, tunnel inclination on anteroposterior radiographs, and exit location on lateral radiographs. Secondary outcomes encompass tunnel-related complications and reconstruction failures. To identify potential risk factors for shorter tunnel lengths and posterior exits, regression analysis was conducted. Results Tunnel parameters of 234 patients were analyzed. In the modified portal group, femoral tunnel length and inclination were significantly higher, with tunnels exhibiting a more anterior exit position (p

Abstract Background This study aimed to investigate the distribution of femoral tunnel and explore the influences of bone tunnel positions on knee functions. The bone landmark positioning method was used to position the femoral tunnel during the anatomical reconstruction surgery in patients with anterior cruciate ligament (ACL) rupture. Methods Data of patients who underwent anatomical reconstruction of the ACL between January 2015 and July 2018, were retrospectively analyzed. The distribution of the femoral tunnel was recorded on 3-D CT after surgery. The tunnel positions were classified into good and poor position groups based on whether the position was in the normal range (24–37% on the x-axis and 28–43% on the y-axis). The Lysholm and IKDC scores, KT-1000 side-to-side difference, pivot shift test and Lachman test results of the knee joints were recorded, and then the differences in knee joint functions between the two groups were analyzed. Results 84 eligible patients (84 knees) were finally included in this study. Twenty-two and 62 of the patients were categorized in the good and poor position groups, respectively, and the rate of good position was 26.2%. The distribution of bone tunnel was as follows: (x-axis) deep position in 10 patients (12%), normal position in 58 patients (69%), and shallow position in 16 patients (19%); (y-axis) high position in 54 patients (64%), normal position in 26 patients (31%), and low position in 4 patients (5%). 1 year later, the Lysholm and IKDC scores were significantly better in the good position group (P

Purpose: The aim of this retrospective cohort study was to investigate whether the apex of the deep cartilage (ADC) could help surgeons position the femoral tunnel accurately in remnant-preserving anterior cruciate ligament (ACL) reconstruction (ACLR). Methods: In the current retrospective cohort study, a total of 134 patients who underwent ACLR between 2016 and 2020 were included. The femoral tunnel position was located using ADC as the landmark. The patients were divided into two groups: the remnant-preserving group (RP group, n = 68) underwent remnant-preserving ACLR, and the nonremnant group (NRP group, n = 66) underwent traditional ACLR with remnant removal. Postoperatively, the femoral tunnel position was evaluated on 3D-CT. The length from the ADC to the shallow cartilage margin (L) and to the centre of the femoral tunnel (l) and the length from the centre of the femoral tunnel to a low cartilage ratio in the direction from high to low (H) were measured. Results: The l/L values of the RP and NRP groups were both 0.4 ± 0.1 after rounding (n.s.), and the H values were 9.3 ± 1.6 mm and 9.3 ± 1.7 mm, respectively (n.s.). There was no significant difference in l/L or H between the two groups. The estimation plot also showed high consistency of H and l/L of the two groups. The inter- and intraobserver reliability of I, L, l/L, and H were almost perfect. Conclusions: The apex of the deep cartilage is a good landmark for positioning the femoral tunnel in remnant-preserving ACL reconstruction. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Background: Portal positioning in arthroscopic anterior cruciate ligament reconstruction is critical in facilitating the drilling of the femoral tunnel. However, the traditional approach has limitations. A modified inferior anteromedial portal was developed. Therefore, this study aims to compare the modified and conventional far anteromedial portals for femoral tunnel drilling, assessing factors such as tunnel length, inclination, iatrogenic chondral injury risk, and blowout. Material and methods: Patients scheduled for hamstring autograft-based anatomical single-bundle arthroscopic anterior cruciate ligament reconstruction were divided into two groups: modified and far anteromedial groups. Primary outcomes include differences in femoral tunnel length intraoperatively, tunnel inclination on anteroposterior radiographs, and exit location on lateral radiographs. Secondary outcomes encompass tunnel-related complications and reconstruction failures. To identify potential risk factors for shorter tunnel lengths and posterior exits, regression analysis was conducted. Results: Tunnel parameters of 234 patients were analyzed. In the modified portal group, femoral tunnel length and inclination were significantly higher, with tunnels exhibiting a more anterior exit position (p < 0.05). A higher body mass index exerted a negative influence on tunnel length and inclination. However, obese patients in the modified portal group had longer tunnels, increased inclination, and a lower risk of posterior exit. Only a few tunnel-related complications were observed in the far anteromedial group. Conclusion: The modified portal allowed better control of tunnel length and inclination, ensuring a nonposterior femoral tunnel exit, making it beneficial for obese patients. [ABSTRACT FROM AUTHOR]

Purpose: To investigate progressive tunnel widening and its correlation with postoperative outcomes after anterior cruciate ligament (ACL) reconstruction using allografts. Methods: Sixty-five patients who underwent ACL reconstruction using a tibialis anterior allograft between 2015 and 2017 were enrolled. Femoral and tibial tunnel widths were measured on anteroposterior (AP) and lateral radiographs immediately and at 3, 6, 12, and 24 months postoperatively. Average femoral and tibial tunnel widths in AP and lateral views were calculated at three different measurement points. Tunnel widening was calculated as the difference in tunnel width immediately and 2 years postoperatively. The correlation between tunnel widening and the postoperative results was analysed. Results: Tunnel width changes between immediate and 2 years postoperatively were as follows, in AP and lateral views, respectively: femur, 3.0 mm ± 1.5 mm and 2.4 mm ± 1.4 mm; and tibia, 2.8 mm ± 1.4 mm and 2.9 mm ± 1.5 mm. Femoral tunnel widths significantly increased until 1 year, but not from 1 to 2 years postoperatively. Tibial tunnel width significantly increased until 2 years postoperatively. In all tunnels, the increments in tunnel widening decreased over time. Increased knee laxity significantly correlated with greater femoral tunnel widening in AP (r = 0.346, P = 0.006) and lateral views (r = 0.261, P = 0.049). Conclusion: Femoral tunnel widths gradually increased until 1 year postoperatively, and tibial tunnel widths increased until 2 years after ACL reconstruction with allografts. The tunnel widening rate gradually decreased over time. Femoral tunnel widening of 3.7 mm and 3.2 mm on AP and lateral views, respectively, were the cut-off values for postoperative knee laxity. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: Flattened femoral tunnels were recently applied in anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Little is known about the biomechanical effect of such changes during knee flexion. The aim of the present simulation study was to assess the effect of altered ACL direct insertion coverage on the biomechanics of the graft and bone tunnel. Methods: Five finite element (FE) models, including a round femoral tunnel and four progressively flattened rounded rectangular femoral tunnels, were established to represent the ACL reconstructions. In vivo knee kinematics data obtained from the validated dual fluoroscopic imaging techniques controlled the FE models to simulate lunge motions. The maximal principal stress of the graft and the volume of equivalent strain within 1000–3000 microstrain (V1000-3000) of the cancellous bone were subsequently calculated at 0°, 30°, 60° and 90° of knee flexion. Results: A lower stress state on the graft and a more beneficial strain state on the cancellous bone were observed when the femoral tunnel better covered the ACL direct insertion. The average maximal principal stress of each model were 3.93 ± 0.60 MPa, 3.82 ± 0.54 MPa, 3.43 ± 0.44 MPa, 3.45 ± 0.44 MPa and 3.05 ± 0.43 MPa, respectively. The average V1000-3000 of the cancellous bone of each model were 179.06 ± 89.62 mm3, 221.40 ± 129.83 mm3, 247.57 ± 157.78 mm3, 282.74 ± 178.51 mm3 and 295.71 ± 162.59 mm3, respectively. Both the stress and strain values exhibited two peaks during the flexion simulation. The highest value occurred at 30° of flexion, and the second highest value occurred at 90° of flexion. Conclusions: Increased ACL direct insertion coverage provided more positive biomechanical effects after anatomical single-bundle ACL reconstruction during knee flexion. [ABSTRACT FROM AUTHOR]

Positioning of the femoral tunnel during anterior cruciate ligament (ACL) reconstruction is the most crucial factor for successful procedure. Owing to the inter-individual variability in the intra-articular anatomy, it can be challenging to obtain precise tunnel placement and ensure consistent results. Currently, the three-dimensional (3D) reconstruction of computed tomography (CT) scans is considered the best method for determining whether femoral tunnels are positioned correctly. Postoperative 3D-CT feedback can improve the accuracy of femoral tunnel placement. Precise tunnel formation obtained through feedback has a positive effect on graft maturation, graft failure, and clinical outcomes after surgery. However, even if femoral tunnel placement on 3D CT is appropriate, we should recognize that acute graft bending negatively affects surgical results. This review aimed to discuss the implementation of 3D-CT evaluation for predicting postoperative outcomes following ACL re-construction. Reviewing research that has performed 3D CT evaluations after ACL reconstruction can provide clinically significant evidence of the formation of ideal tunnels following anatomic ACL reconstruction. [ABSTRACT FROM AUTHOR]

Purpose: In this study, our aim was to reveal the effect of the medial femoral offset aimer usage through the femoral tunnel entry and exit points and the tunnel length during femoral tunnel drilling in arthroscopic anterior cruciate ligament (ACL) reconstruction. Methods: One hundred patients who underwent arthroscopic single-bundle ACL reconstruction were included in the study. Group 1 consisted of 50 patients who underwent femoral tunnel drilling using a medial portal offset aimer device, while Group 2 consisted of 50 patients who were operated on using the freehand technique. Both groups were compared in terms of femoral tunnel and graft tunnel lengths, femoral tunnel angle in the coronal plane, and the location of the femoral tunnel entry and exit points. Results: The mean femoral tunnel and graft tunnel lengths were significantly longer in Group 2 (p = 0.000). There was no significant difference in terms of localization of the femoral tunnel entry point in both the axial and sagittal planes. The tunnel exit point was located significantly more posterior in Group 1 in the axial plane (p = 0.028). There was no significant difference in terms of the coronal plane femoral tunnel angle between the two groups. Conclusion: In arthroscopic ACL reconstructions, more successful results may be obtained with the freehand technique compared to drilling with a femoral offset aimer. For an experienced orthopedic surgeon, using a medial portal offset aimer device during femoral tunnel drilling does not seem necessary. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the distribution of femoral tunnel and explore the influences of bone tunnel positions on knee functions. The bone landmark positioning method was used to position the femoral tunnel during the anatomical reconstruction surgery in patients with anterior cruciate ligament (ACL) rupture. Methods: Data of patients who underwent anatomical reconstruction of the ACL between January 2015 and July 2018, were retrospectively analyzed. The distribution of the femoral tunnel was recorded on 3-D CT after surgery. The tunnel positions were classified into good and poor position groups based on whether the position was in the normal range (24–37% on the x-axis and 28–43% on the y-axis). The Lysholm and IKDC scores, KT-1000 side-to-side difference, pivot shift test and Lachman test results of the knee joints were recorded, and then the differences in knee joint functions between the two groups were analyzed. Results: 84 eligible patients (84 knees) were finally included in this study. Twenty-two and 62 of the patients were categorized in the good and poor position groups, respectively, and the rate of good position was 26.2%. The distribution of bone tunnel was as follows: (x-axis) deep position in 10 patients (12%), normal position in 58 patients (69%), and shallow position in 16 patients (19%); (y-axis) high position in 54 patients (64%), normal position in 26 patients (31%), and low position in 4 patients (5%). 1 year later, the Lysholm and IKDC scores were significantly better in the good position group (P < 0.05), the KT-1000 side to side difference, the pivot shift test and Lachman test results were better in the good position group (P < 0.05). Conclusions: The bone tunnels were found to be distributed in and beyond the normal range using the bone landmark method to position the femoral tunnel in the single-bundle anatomical reconstruction of ACL, while the rate of good bone tunnel position was low. The knee joint function scores and stability were lower in patients with poor position of the femoral tunnel. [ABSTRACT FROM AUTHOR]

Purpose: Isolated MPFL reconstruction (iMPFLR) is increasingly used for the surgical treatment of treatment for recurrent patella dislocation. The purpose of this study was to evaluate the influence of tunnel widening and migration on clinical outcomes after iMPFL using a CT-scannographic analysis at 6 months postoperatively. Methods: One hundred and sixty patients (91 females for 69 males) with an average age of 23 years [14–54] who underwent iMPFLR and had an evaluation scan at 6 months postoperatively were evaluated with a mean follow-up of 97 ± 89 months [12 to 166]. Functional International Knee Documentation Committee (IKDC) Score, Kujala score, and joint mobility were assessed preoperatively, at 6 months and at the latest follow-up. The IKDC and Kujala scores were expressed as the difference between pre- and postoperative scores (dIKDC and dKujala). The position of the femoral tunnel was assessed according to the Schöttle criteria on post-operative radiographic profiles. Tunnel widening (at three levels of measurement) and the migration of the center of the tunnel were studied on a CT-scan analysis at 6 months. Any correlation and regression between the evolution of the clinical scores and the measured scannographic parameters were investigated. The relationships between tunnel position and tunnel changes were also studied. Results: Between pre- and post-op, the IKDC (45 ± 13 to 80 ± 15, p < 0.001) and Kujala (55 ± 11 to 87 ± 12, p < 0.001) scores were significantly improved. Patients with tunnel changes had decreased clinical and functional results at 6 months post-op of an iMPFLR (p < 0.001). These changes in the femoral tunnel, evidenced by a tunnel entrance widening and migration of the tunnel center, were related to an initial malposition of the tunnel (p < 0.001). Conclusion: In iMPFLR, changes in the femoral tunnel, corresponding to dilatation and migration of the tunnel center, may occur. These changes are increased by the initial malpositioning of the femoral tunnel and are correlated with less good clinical and functional outcomes. Level of evidence: Level IV. [ABSTRACT FROM AUTHOR]

Background and Objectives: The aim of this study is to investigate the femoral tunnel geometry (femoral tunsnel location, femoral graft bending angle, and femoral tunnel length) on three-dimensional (3D) computed tomography (CT) and graft inclination on magnetic resonance imaging (MRI) after anatomic anterior cruciate ligament (ACL) reconstruction using a flexible reamer system. Materials and Methods: A total of 60 patients who underwent anatomical ACL reconstruction (ACLR) using a flexible reamer system were retrospectively reviewed. One day after the ACLR procedure was performed, all patients underwent three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI). The femoral tunnel location, femoral graft bending angle, femoral tunnel length, and graft inclination were assessed. Results: In the 3D-CTs, the femoral tunnel was located at 29.7 ± 4.4% in the posterior to anterior (deep to shallow) direction and at 24.1 ± 5.9% in the proximal to distal (high to low) direction. The mean femoral graft bending angle was 113.9 ± 5.7°, and the mean femoral tunnel length was 35.2 ± 3.1 mm. Posterior wall breakage was observed in five patients (8.3%). In the MRIs, the mean coronal graft inclination was 69.2 ± 4.7°, and the mean sagittal graft inclination was 52.4 ± 4.6°. The results of this study demonstrated that a comparable femoral graft bending angle and longer femoral tunnel length were observed compared with the reported outcomes from previous studies that used the rigid reamer system. Conclusions: ACLR using a flexible reamer system allowed for an anatomic femoral tunnel location and a comparable graft inclination to that of the native ACL. In addition, it achieved a tolerable femoral graft bending angle and femoral tunnel length. [ABSTRACT FROM AUTHOR]

Background: Due to the similarity among specimens in the height of the anterior cruciate ligament (ACL) on the distal proximal axis in relation to the proximal posterior cartilage of the lateral femoral condyle (point C), it is known this point can be used as an arthroscopic intraoperative parameter to define the position of the femoral tunnel in ACL reconstruction. Indications: For ACL reconstruction, point C can be used as an arthroscopic intraoperative parameter to define the position of the femoral tunnel on the distal proximal and anteroposterior axes. Technique Description: For access to the joint, standard arthroscopic ports, both anterolateral (AL) and anteromedial (AM), are used. By directing the camera toward the posterior region of the lateral femoral condyle through the AM port, it is possible to visualize the end of the posterior and proximal articular cartilage, the so-called C point. In this case, we sought to position the center of the femoral tunnel in the center of the AM band of the ACL. Holding the camera through the AM portal and visualizing point C, a millimeter-scale femoral guide is introduced through the AL portal toward the posterior femoral cartilage (point C) and positioned over it, creating a line between point C and the lateral distal femoral cartilage. The distance between point C and the distal femoral cartilage is measured. At this time, an accessory AM portal 1.5 cm from the AM port is constructed. Through it, with the aid of an ice pick or radiofrequency tip, a marking is made in the deep to shallow axis at 35% of this distance. Then, approximately 2 mm above the imaginary line formed by the union of point C and the lateral distal femoral cartilage, the center of the femoral tunnel is marked. Results: Point C is an anatomical landmark that is easy to view and is present in all knees; thus, it can be used as a reference during surgery for positioning the femoral tunnel. Discussion/Conclusion: Point C can be used as an arthroscopic intraoperative parameter to define the position of the femoral tunnel in ACL reconstruction. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication. Graphical Abstract This is a visual representation of the abstract. [ABSTRACT FROM AUTHOR]

INTRODUCTION: We aimed to compare whether the visualisation provided by arthroscopic hyperflexion and Figure 4 has an effect on femoral tunnel placement in patients undergoing single bundle Anterior Cruciate Ligament Reconstruction (ACLR). MATERIALS AND METHODS: We retrospectively evaluated 93 patients who underwent single-band ACLR for Anterior Cruciate Ligament (ACL) injury between 2016 and 2019. Eighty patients met the inclusion criteria with a minimum follow-up of 12 months. We divided the patients into Group 1 (figure 4) and Group 2 (hyperflexion). We analysed the demographic, radiological and functional outcomes of the patients. The functional Lysholm score, operative time, radiological Quadrant method (% proximal-distal and % anterior-posterior) measurements, tunnel lengths, axial and coronal plane angles, and iatrogenic chondral injury in the medial femoral condyle were evaluated. RESULTS: Iatrogenic chondral injury developed in the medial femoral condyle in a total of seven patients in both groups: one patient in group 1 (Figure 4) and six patients in group 2 (Hyperflexion). Although statistically insignificant, iatrogenic medial femoral condyle damage was less in group 1. The statistical analysis between surgical operation time (p = 0.046) and tunnel lengths (p = 0.042) was significant. CONCLUSION: The position of figure 4 provides visualisation of lateral intercondylar notch better than hyperflexion. In the reaming stage, the medial femoral condyle is less damaged in group 1 (Figure 4). In ACLR, which has a long learning curve, short surgery time is seen as an important advantage for surgeons who have just started doing ACLR. We think that it can be used as an alternative method to hyperflexion in the learning process and maybe shorten the learning curve process.

Arthroscopic ACL reconstruction is the current standard care of treatment for anterior cruciate ligament (ACL) injuries. Modified transtibial (mTT) and anteromedial portal (AMP) techniques aim at the anatomical placement of femoral tunnel. Controversy existed in the literature with regard to the outcome of these techniques. Hence, we designed a retrospective comparative study to analyse the clinical and functional outcomes of mTT and AMP techniques. We hypothesized that there would be no difference between the clinical and functional outcomes in mTT and AMP techniques. This retrospective observational study was conducted in consecutive patients who underwent arthroscopic ACL reconstruction using semitendinosus-gracilis (STG) quadrupled graft in our tertiary care centre with a minimum follow-up of two years. Out of 69 patients, 37 had undergone ACL reconstruction by mTT technique and remaining by AMP technique. All the patients were assessed clinically by anterior drawer, Lachman's, pivot shift and single-legged hop test. Lysholm Knee Scoring Scale and International Knee Documentation Committee (IKDC) subjective knee evaluation score were used for the functional status. Knee instability was assessed objectively by KT-1000 arthrometer. There was no statistically significant difference in baseline demographic characteristics between mTT and AMP groups. At the end of 2 years, no statistically significant difference was noted in the anterior drawer and Lachman's test. Though not significant, IKDC scores and Lysholm's scores showed a better outcome in the AMP group when compared to the mTT group. AMP group showed significantly better outcome with KT-1000 arthrometer. Based on the results obtained, we presume that overall both mTT and AMP have similar functional outcome. However, as AMP technique offers significantly improved subjective rotational stability on pivot shift test, better hop limb symmetry index and KT 1000 readings compared to mTT, we suggest AMP over mTT. [ABSTRACT FROM AUTHOR]

Recurrent patellar dislocation is a commonly encountered patellofemoral disease. Prompt surgical intervention is indicated for recurrent dislocation to restore patellofemoral stability. As one of the most preferred procedures, medial patellofemoral ligament (MPFL) reconstruction has been implemented on a large scale. Femoral tunnel placement remains a crucial technical issue during MPFL reconstruction and is critical to ensure the isometry and proper tension of the graft. Currently, visual–palpatory anatomic landmarks and fluoroscopy-guided radiographic landmarks comprise the main approaches to intraoperative femoral tunnel positioning. However, the accuracy of both methods has been questioned. This article introduces an arthroscopic femoral tunnel placement technique. Apart from traditional anteromedial and anterolateral portals, two auxiliary arthroscopic portals are specially designed. The adductor tubercle, the medial epicondyle and the posterior edge are selected as main anatomic landmarks and are directly visualized in sequence under arthroscope. The relative position between the femoral attachment of the MPFL and the three landmarks is measured on preoperative three-dimensional computed tomography, providing semi-quantified reference for intraoperative localization. This technique achieves minimally invasive tunnel placement without X-ray exposure, and especially suits obese patients for whom palpatory methods are difficult to perform. [ABSTRACT FROM AUTHOR]

Background: Although numerous clinical studies have compared transtibial (TT) and anteromedial portal (AMP) drilling of femoral tunnels during anterior cruciate ligament reconstruction (ACLR), there is no high-quality, evidence-based consensus regarding which technique affords the best outcome. Hypothesis: There would be no difference between the TT and AMP techniques in terms of knee stability, patient-reported outcomes, incidence of revision, and radiological results. Study Design: Meta-analysis; Level of evidence, 2. Methods: The PubMed and EMBASE databases were searched from inception to February 1, 2021. Level 1 and 2 clinical trials that compared TT and AM techniques were included. Data were meta-analyzed for the outcome measures of knee stability, patient-reported functional outcomes, incidence of revision, and radiological results. Dichotomous variables were presented as odds ratios (ORs), and continuous variables were presented as mean differences (MDs) and standard mean differences (SMDs). Results: The meta-analysis included 18 clinical studies, level of evidence 1 or 2, that involved 53,888 patients. Pooled data showed that the AMP group had a lower side-to-side difference (SMD, 0.22; 95% CI, 0.06 to 0.39; P =.009), a lower incidence of pivot-shift phenomenon (OR, 3.69; 95% CI, 1.26 to 10.79; P =.02), and a higher postoperative Lysholm score (SMD, −0.26; 95% CI, −0.44 to −0.08; P =.005) than the TT group. However, no statistically significant differences were seen in other outcomes, including subjective International Knee Documentation Committee scores (SMD, –0.11; 95% CI, –0.30 to 0.09; P =.30) or grades (OR, 0.93; 95% CI, 0.35 to 2.49; P =.89), postoperative activity level (MD, –0.14; 95% CI, –0.42 to 0.15; P =.35), and incidence of revision ACLR (OR, 1.04; 95% CI, 0.93 to 1.16; P =.45). The TT technique was more likely to create longer (SMD, 1.05; 95% CI, 0.05 to 2.06; P =.04) and more oblique (SMD, 0.81; 95% CI, 0.51 to 1.11; P <.001) femoral tunnels than the AMP technique, and a higher height ratio of the aperture position was detected with the TT technique (SMD, −3.51; 95% CI, −5.54 to −1.49; P <.001). Conclusion: The AMP technique for ACLR may be more likely to produce better knee stability and improved clinical outcomes than the TT technique, but no difference was found in the incidence of revision between the 2 groups. [ABSTRACT FROM AUTHOR]

Purpose: To develop a simple and effective method for evaluating the femoral tunnel position using the apex of the deep cartilage (ADC) as the landmark. Methods: A total of 52 patients who underwent arthroscopic ACL reconstruction were recruited between June and September 2021. The femoral tunnel was placed on the central point of the anteromedial footprint with an accessory anteromedial and a high anterolateral portal. Then, the length from the ADC to the shallow cartilage margin (L1) and to the center of the femoral tunnel (l1), as well as the center to the low cartilage margin (H1, intraoperative height), was measured under arthroscopy and on postoperative CT scans (L2, l2 and H2). Moreover, intraoperative and postoperative cartilage ratios were equivalent to l1/L1 and l2/L2, respectively. Linear regression, Pearson correlation and Bland–Altman analysis were performed to evaluate the consistency between these two measurements of cartilage ratio (l/L) and height (H). Results: The mean age at the time of surgery was 28.7 years; 42 patients were male, and 17 patients were hurt in the left knee among 52 patients. The intraoperative cartilage ratio was 0.37 ± 0.04, and the height was 8.1 ± 1.1 mm with almost perfect inter-observer reproducibility. After the surgery, the cartilage ratio and height were measured as 0.39 ± 0.04 and 8.2 ± 1.3 mm on 3D–CT, respectively, with almost perfect intra- and inter-observer reproducibility. Significant positive correlations and linear regression were detected in the cartilage ratio (r = 0.844, p < 0.001), and height (r = 0.926, p < 0.001) intraoperatively and postoperatively. The Bland–Altman plot also showed excellent consistency between arthroscopy and 3D–CT. Conclusions: The ADC is a good landmark in the assessment of femoral tunnel position, with excellent consistency between intraoperative arthroscopic measurements and postoperative 3D–CT. ClinicalTrials.gov Identifier: NCT04937517. Level of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to comparatively evaluate the accuracy of femoral tunnel positioning after anatomic single-bundle anterior cruciate ligament (ACL) reconstruction performed with the remnant preservation (RP) technique versus the non-remnant preservation (NRP) technique. Methods: A retrospective review of 145 patients who underwent ACL reconstruction from May 2020 to May 2022 were performed in this single-surgeon study. A total of 120 patients met the inclusion criteria and were allocated into two groups according to the surgical technique (i.e. RP group and NRP group). The relative location of the femoral tunnel in the lateral condyle was evaluated as a percentage using a standardized grid system on the three-dimensional computed tomography (3D-CT) image. The accuracy and precision of the RP group were assessed based on published anatomical data in direct comparison with the NRP group. Results: According to the surgical procedure, 57 of the 120 patients included were allocated into the RP group, and 63 into the NRP group. Significant differences were observed between the two groups in terms of tunnel position (posterior-to-distal (PD): 28.4 ± 5.4% (RP) vs. 31.8 ± 5.3% (NRP); P = 0.01), (anterior-to-posterior (AP): 32.6 ± 7.7% (RP) vs. 38.8 ± 7.7% (NRP); P = 0.00), while no significant differences were found in terms of the accuracy (8.6% (RP) vs. 8.9% (NRP); n.s) and precision (4.4% (RP) vs. 5.6% (NRP); n.s) of femoral tunnel positioning between the two groups. Conclusions: From this single-surgeon study, it was concluded that there were no differences in the creation of ACL femoral tunnel between the RP technique and the non-remnant preserving technique. Meanwhile, the RP technique would not sacrifice the ideal position of the femoral tunnel and is able to retain the possible benefits of the ACL stump. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]

Abstract Purpose Flattened femoral tunnels were recently applied in anatomical single‐bundle anterior cruciate ligament (ACL) reconstruction. Little is known about the biomechanical effect of such changes during knee flexion. The aim of the present simulation study was to assess the effect of altered ACL direct insertion coverage on the biomechanics of the graft and bone tunnel. Methods Five finite element (FE) models, including a round femoral tunnel and four progressively flattened rounded rectangular femoral tunnels, were established to represent the ACL reconstructions. In vivo knee kinematics data obtained from the validated dual fluoroscopic imaging techniques controlled the FE models to simulate lunge motions. The maximal principal stress of the graft and the volume of equivalent strain within 1000–3000 microstrain (V1000‐3000) of the cancellous bone were subsequently calculated at 0°, 30°, 60° and 90° of knee flexion. Results A lower stress state on the graft and a more beneficial strain state on the cancellous bone were observed when the femoral tunnel better covered the ACL direct insertion. The average maximal principal stress of each model were 3.93 ± 0.60 MPa, 3.82 ± 0.54 MPa, 3.43 ± 0.44 MPa, 3.45 ± 0.44 MPa and 3.05 ± 0.43 MPa, respectively. The average V1000‐3000 of the cancellous bone of each model were 179.06 ± 89.62 mm3, 221.40 ± 129.83 mm3, 247.57 ± 157.78 mm3, 282.74 ± 178.51 mm3 and 295.71 ± 162.59 mm3, respectively. Both the stress and strain values exhibited two peaks during the flexion simulation. The highest value occurred at 30° of flexion, and the second highest value occurred at 90° of flexion. Conclusions Increased ACL direct insertion coverage provided more positive biomechanical effects after anatomical single‐bundle ACL reconstruction during knee flexion.

Purpose: During the transportal technique of anterior cruciate ligament (ACL) reconstruction, tunnel outlet location can be varied depending on certain anatomical and technical characteristics. Therefore, we aimed to find out the acceptable zone of endobutton location by introducing several radiographic values., Methods: Postoperative lateral radiographs of 72 patients were assessed to measure the distances from the centre of the button to the posterior femoral cortex (D1) and to the most distal point of the lateral condyle (D2). Furthermore, based on the anteroposterior (AP) radiographs, the distances from the centre of the button to the lateral femoral cortex (D3) and from the centre of the button to the line connecting the most distal points of the medial and lateral femoral condyles (D4) were assessed. To measure the sensitivity and specificity of each radiographic value (D1, D2, D3 and D4), the area under the receiver operating characteristic curve was calculated. The alpha angle and femoral tunnel length values were considered as gold standards., Results: Analyses showed that the mean values for D1, D2, D3 and D4 were 13.20 ± 0.54, 39.44 ± 0.31, 1.65 ± 0.15 and 42.66 ± 0.47 mm, respectively. The mean angle was found to be 38.6 ± 0.3°, and the mean femoral tunnel length was 38.6 ± 0.2 mm. Age was significantly related to D2 and the diameter of the femur in AP X-ray, while body mass index had a significant relation with D3 ( p  < 0.05)., Conclusion: In this study, a new method was proposed to evaluate the accuracy of anatomical tunnel placement in ACL reconstruction surgery postoperatively. The statistical analysis of the measured variables showed that the mean ratios were 21.79 ± 0.87 for D1, 65.65 ± 0.63 for D2 and 51.90 ± 0.73 for D4. The results indicated that if the tunnel exit location and endobutton placement in the postoperative radiological images fall within the suggested areas, it can be meaningfully concluded that the tunnel is correctly positioned intraarticularly and the ligament reconstruction is anatomical., Level of Evidence: Level III., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Journal of Experimental Orthopaedics published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background: As machine learning becomes increasingly utilized in orthopaedic clinical research, the application of machine learning methodology to cohort data from the Multicenter ACL Revision Study (MARS) presents a valuable opportunity to translate data into patient-specific insights., Purpose: To apply novel machine learning methodology to MARS cohort data to determine a predictive model of revision anterior cruciate ligament reconstruction (rACLR) graft failure and features most predictive of failure., Study Design: Cohort study; Level of evidence, 3., Methods: The authors prospectively recruited patients undergoing rACLR from the MARS cohort and obtained preoperative radiographs, surgeon-reported intraoperative findings, and 2- and 6-year follow-up data on patient-reported outcomes, additional surgeries, and graft failure. Machine learning models including logistic regression (LR), XGBoost, gradient boosting (GB), random forest (RF), and a validated ensemble algorithm (AutoPrognosis) were built to predict graft failure by 6 years postoperatively. Validated performance metrics and feature importance measures were used to evaluate model performance., Results: The cohort included 960 patients who completed 6-year follow-up, with 5.7% (n = 55) experiencing graft failure. AutoPrognosis demonstrated the highest discriminative power (model area under the receiver operating characteristic curve: AutoPrognosis, 0.703; RF, 0.618; GB, 0.660; XGBoost, 0.680; LR, 0.592), with well-calibrated scores (model Brier score: AutoPrognosis, 0.053; RF, 0.054; GB, 0.057; XGBoost, 0.058; LR, 0.111). The most important features for AutoPrognosis model performance were prior compromised femoral and tibial tunnels (placement and size) and allograft graft type used in current rACLR., Conclusion: The present study demonstrated the ability of the novel AutoPrognosis machine learning model to best predict the risk of graft failure in patients undergoing rACLR at 6 years postoperatively with moderate predictive ability. Femoral and tibial tunnel size and position in prior ACLR and allograft use in current rACLR were all risk factors for rACLR failure in the context of the AutoPrognosis model. This study describes a unique model that can be externally validated with larger data sets and contribute toward the creation of a robust rACLR bedside risk calculator in future studies., Registration: NCT00625885 (ClinicalTrials.gov identifier)., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study was funded by the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant 5R01-AR060846). See Supplemental Material for individual disclosures. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2024.)

Abstract Background Transportal (TP) and all-inside techniques (AIT) are the most commonly used anterior cruciate ligament (ACL) reconstruction procedures in current clinical practice. However, there is an ongoing debate over which procedure is superior. Therefore, the purpose of this systematic review was to evaluate and compare the clinical outcomes and complications of these two techniques to propose recommendations for future application. Our primary hypothesis was that AIT is a superior ACLR technique compared to TP. Methods A systematic literature review, using PRISMA guidelines, was conducted using PubMed, Medline, Google Scholar, and EMBASE, up to February 2021 to identify studies focusing on AIT and TP techniques of ACL reconstruction. We excluded animal experiments, cadaveric studies, retrospective studies, case reports, technical notes, and studies without quantitative data. Patients’ characteristics, surgical technical features, along with postoperative follow-up and complications were extracted and reported accordingly. Methodological quality of the included studies was assessed using the Modified Coleman Methodology Score (MCMS). Results A total of 44 studies were selected for this review, of which four were comparative studies. A total of 923 patients underwent AIT and 1678 patients underwent the TP technique for ACLR. A single semitendinosus graft was commonly used in the AIT compard to combined semitendinosus and gracilis graft in the TP group. The postoperative increase in International Knee Documentation Committee (IKDC), Lysholm, KT-1000, and Short Form-12 (physical and mental) scores were similar in the AIT group and the TP group. Contrastingly, the VAS pain score was significantly lower in the AIT group compared to the TP group. Furthermore, the pooled complication rates from all studies were similar between the two groups (AIT: 54 patients, 8.26% vs. PT: 55 patients, 6.62%). However, the four studies that prospectively compared AIT and TP techniques showed lesser complications in the AIT group than the TP group. Conclusion Since the future trend in orthopedic surgery is toward less invasive and patients’ satisfaction with good outcomes, AIT is a good alternative method considering preserving bony tissue and gracilis tendon with less post-operative pain, along with more knee flexor strength and equal outcomes compared to conventional ACL reconstruction surgery. Level of Evidence II.

Positioning of the femoral tunnel during anterior cruciate ligament (ACL) reconstruction is the most crucial factor for successful procedure. Owing to the inter-individual variability in the intra-articular anatomy, it can be challenging to obtain precise tunnel placement and ensure consistent results. Currently, the three-dimensional (3D) reconstruction of computed tomography (CT) scans is considered the best method for determining whether femoral tunnels are positioned correctly. Postoperative 3D-CT feedback can improve the accuracy of femoral tunnel placement. Precise tunnel formation obtained through feedback has a positive effect on graft maturation, graft failure, and clinical outcomes after surgery. However, even if femoral tunnel placement on 3D CT is appropriate, we should recognize that acute graft bending negatively affects surgical results. This review aimed to discuss the implementation of 3D-CT evaluation for predicting postoperative outcomes following ACL re-construction. Reviewing research that has performed 3D CT evaluations after ACL reconstruction can provide clinically significant evidence of the formation of ideal tunnels following anatomic ACL reconstruction.

Background: Arthroscopically aided anterior cruciate ligament reconstruction using hamstring graft can be fixed to femoral condyle by suspensory and aperture fixation methods. Objectives: To investigate functional outcomes with these fixation methods as measured by the Lysholm knee score of Hamstring autografts. Methods: 50 patients of clinically and radiologically diagnosed ACL tear fulfilling the inclusion and exclusion criteria were randomized into two groups to undergo arthroscopic ACL reconstruction using quadrupled hamstring graft with suspensory (n=25) and aperture (n=25) fixation methods on femoral side. They were compared post operatively with Lysholm score, clinical laxity tests and percentage of tunnel enlargement using computed tomograms at 01 year. Results: At the end of 6 months there was no much difference in Lysholm score between both the groups (P =0.63) and at the end of 01 year aperture group had slightly better outcome. However, the difference was not statistically significant (p =0.13). There were more tunnels widening in the suspensory group especially of the femoral tunnel in the coronal plane. However, the amount of tunnel widening in both the groups was not significant statistically (P =0.071 and P =0.963). Conclusions: Aperture and Suspensory fixation methods of hamstring graft at femoral condyle in ACL reconstruction are comparable clinically and there is no advantage of one particular method over other. [ABSTRACT FROM AUTHOR]

Abstract Background Notchplasty is a surgical technique often performed during anterior cruciate ligament reconstruction (ACLR) with widening of the intercondylar notch of the lateral distal femur to avoid graft impingement. The purpose of this study was to correlate femoral-tunnel length with 3-dimensional (3D) drilling angle through the anteromedial (AM) portal with and without notchplasty. Materials and methods Computer data were collected from an anatomical study using 16 cadaveric knees. The anterior cruciate ligament (ACL) femoral insertion was dissected and outlined for gross anatomical observation. The dissected cadaveric knees were scanned by computed tomography (CT). Three-dimensional measurements were calculated using software (Geomagic, Inc., Research Triangle Park, NC, USA) and included the center of the ACL footprint and the size of the ACL femoral footprint. The femoral-tunnel aperture centers were measured in the anatomical posterior-to-anterior and proximal-to-distal directions using Bernard’s quadrant method. The ACL tunnel was created 3-demensionally in the anatomical center of femoral foot print of ACL using software (SolidWorks®, Corp., Waltham, MA, USA). The 8-mm cylinder shaped ACL tunnel was rested upon the anatomical center of the ACL footprint and placed in three different positions: the coronal plane, the sagittal plane, and the axial plane. Finally, the effect of notchplasty on the femoral-tunnel length and center of the ACL footprint were measured. All the above-mentioned studies performed ACLR using the AM portal. Results The length of the femoral tunnels produced using the low coronal and high axial angles with 5-mm notchplasty became significantly shorter as the femoral starting position became more horizontal. The result was 30.38 ± 2.11 mm on average at 20° in the coronal plane/70° in the axial plane/45° in the sagittal plane and 31.26 ± 2.08 mm at 30° in the coronal plane/60° in the axial plane/45° in the sagittal plane, respectively, comparing the standard technique of 45° in the coronal/45° in the axial/45° in the sagittal plane of 32.98 ± 3.04 mm (P

Background and Objectives: The aim of this study is to investigate the femoral tunnel geometry (femoral tunsnel location, femoral graft bending angle, and femoral tunnel length) on three-dimensional (3D) computed tomography (CT) and graft inclination on magnetic resonance imaging (MRI) after anatomic anterior cruciate ligament (ACL) reconstruction using a flexible reamer system. Materials and Methods: A total of 60 patients who underwent anatomical ACL reconstruction (ACLR) using a flexible reamer system were retrospectively reviewed. One day after the ACLR procedure was performed, all patients underwent three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI). The femoral tunnel location, femoral graft bending angle, femoral tunnel length, and graft inclination were assessed. Results: In the 3D-CTs, the femoral tunnel was located at 29.7 ± 4.4% in the posterior to anterior (deep to shallow) direction and at 24.1 ± 5.9% in the proximal to distal (high to low) direction. The mean femoral graft bending angle was 113.9 ± 5.7°, and the mean femoral tunnel length was 35.2 ± 3.1 mm. Posterior wall breakage was observed in five patients (8.3%). In the MRIs, the mean coronal graft inclination was 69.2 ± 4.7°, and the mean sagittal graft inclination was 52.4 ± 4.6°. The results of this study demonstrated that a comparable femoral graft bending angle and longer femoral tunnel length were observed compared with the reported outcomes from previous studies that used the rigid reamer system. Conclusions: ACLR using a flexible reamer system allowed for an anatomic femoral tunnel location and a comparable graft inclination to that of the native ACL. In addition, it achieved a tolerable femoral graft bending angle and femoral tunnel length.

Purpose: Correct placement of the femoral and tibial tunnels in the anatomic footprint during anterior cruciate ligament reconstruction (ACLR) is paramount for restoring rotatory knee stability. Recent studies have looked at surgeon volume and its outcomes on procedures such as total knee arthroplasty and infection rates, but only few studies have specifically examined tunnel placement after ACLR based on surgeon volume. The purpose of this study was to compare the placement of femoral and tibial tunnels during ACLR between high-volume and low-volume surgeons. It was hypothesized that high-volume surgeons would have more anatomic tunnel placement compared with low-volume surgeons. Methods: A retrospective review of all ACLR performed between 2015 and 2019 at an integrated health care system consisting of both academic and community hospitals with 68 orthopaedic surgeons was conducted. Surgeon volume was categorized as less than 35 ACLR per year (low volume) and 35 or more ACLR per year (high volume). Femoral tunnel placement for each patient was determined using an exact strict lateral radiograph (less than 6 mm of offset between the posterior halves of the medial and lateral condyles) taken after the primary ACLR using the quadrant method. The centre of the femoral tunnel was measured in relation to the posterior–anterior (PA) and proximal–distal (PD) dimensions (normal centre of anatomic footprint: PA 25% and PD 29%). Tibial tunnel placement for each patient was determined on the same lateral radiographs by measuring the mid-sagittal tibial diameter and the centre of the tibial attachment area of the ACL from the anterior tibial margin (normal centre of anatomic footprint: 43%). Each lateral radiograph was reviewed by one of two blinded reviewers. Results: A total of 4500 patients were reviewed, of which 645 patients met all the inclusion/exclusion criteria and were included in the final analysis. There were 228 patients in the low-volume group and 417 patients in the high-volume group. Low-volume surgeons performed a mean of 5 ACLRs per year, whereas surgeons in the high-volume group performed a mean of 40 ACLRs per year. In the PA dimension, the low-volume group had significantly more anterior femoral tunnel placement compared with the high-volume group (32 ± 10% vs 28 ± 9%, p < 0.01). In the PD dimension, the low-volume group had statistically significant more proximal femoral tunnel placement compared to the high-volume group (32 ± 9% vs 35 ± 9%, p < 0.01). For the tibial tunnel, the low-volume group had significantly more posterior tibial tunnel placement compared with the high-volume group (41 ± 10% vs 38 ± 7%, p < 0.01). Conclusion: Low-volume surgeons placed their femoral tunnels significantly more anterior and proximal (high) during ACLR, and placed their tibial tunnels significantly more posterior, compared with high-volume surgeons. Prior research has indicated that anatomic placement of the femoral and tibial tunnels during ACLR leads to improved rotatory knee stability. The findings of this study demonstrate the importance of surgical volume and experience during ACLR. Level of evidence: III. [ABSTRACT FROM AUTHOR]

Background: Radiographic and cadaveric studies have suggested that anatomic anterior cruciate ligament reconstruction (ACLR) femoral tunnel drilling with the use of a flexible reaming system through an anteromedial portal (AM-FR) may result in a different graft and femoral tunnel position compared with using a rigid reamer through an accessory anteromedial portal with hyperflexion (AAM-RR). No prior studies have directly compared clinical outcomes between the use of these 2 techniques for femoral tunnel creation during ACLR. Purpose: To compare revision rates at a minimum of 2 years postoperatively for patients who underwent ACLR with AM-FR versus AAM-RR. The secondary objectives were to compare functional testing and patient-reported outcomes between the cohorts. Study Design: Cohort study; Level of evidence, 3. Methods: Included were consecutive patients at a single academic institution between 2013 and 2018 who underwent primary ACLR without additional ligamentous reconstruction. Patients were separated into 2 groups based on the type of anatomic femoral tunnel drilling: AM-FR or AAM-RR. Graft failure, determined by revision ACLR, was assessed with a minimum 2 years of postoperative follow-up. The authors also compared patient-reported outcome scores (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]) and functional performance testing performed at 6 months postoperatively. Results: A total of 284 (AAM-RR, 232; AM-FR, 52) patients were included. The mean follow-up time was 3.7 ± 1.5 years, with a minimum 2-year follow-up rate of 90%. There was no significant difference in the rate of revision ACLR between the AAM-RR and AM-FR groups (10.8% vs 9.6%, respectively; P =.806). At 6 months postoperatively, there were no significant between-group differences in peak knee extension strength, peak knee flexion strength, limb symmetry indices, or hop testing, as well as no significant differences in IKDC (AAM-RR, 81.1; AM-FR, 78.9; P =.269) or KOOS (AAM-RR, 89.0; AM-FR, 86.7; P =.104). Conclusion: In this limited study, independent femoral tunnel drilling for ACLR using rigid or flexible reaming systems resulted in comparable rates of revision ACLR at a minimum of 2 years postoperatively, with no significant differences in strength assessments or patient-reported outcomes at 6 months postoperatively. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the possibility to access the anatomic femoral insertion of the anterior cruciate ligament (ACL) through trans-tibial (TT) and trans-portal technique, for ACL reconstruction in an independent way. To register anatomical characteristics of the TT tunnels. Methods: Ten formaldehyde preserved knee anatomic articular specimens were dissected. Femoral tunnels were confectioned reproducing the original topography of the ACL. First, the femoral tunnel was made with the independent trans-portal technique. Then, utilizing the tibial stump of the ACL and tibial guides at 45°, the TT tunnels were confectioned trying to match the previously made femoral tunnel by trans-portal technique. Results: In all specimens, match between the TT tunnel with the independent trans-portal tunnel was achieved. Mean values for TT coronal angle was 53,0°, for transversal angle 43,3° and for distance from tunnel to joint line 2,55 cm. A horizontalization and medialization of the TT tunnels had to be made to adequately match with the femoral tunnel made by the independent trans-portal technique. Conclusions: By macroscopic anatomic and independent means, an anatomic femoral tunnel was confectioned with the TT technique matching with the anatomic femoral tunnel made in an independent way. As clinical relevance, the present study allows to anatomically assess the possibility to perform an anatomic femoral tunnel through the TT technique. Level of evidence: V [ABSTRACT FROM AUTHOR]

Background: Anteromedial (AM) femoral tunnel positioning in anterior cruciate ligament reconstruction (ACLR) has been reported by some authors to yield superior clinical and functional outcomes compared with the transtibial (TT) approach; however, differences in the subsequent rates of posttraumatic osteoarthritis (PTOA) are not clear. Purpose: To perform a systematic review and meta-analysis of the literature to evaluate the influence of femoral tunnel positioning during primary ACLR on the development of radiographic PTOA. Study Design: Systematic review and Meta-analysis. Methods: The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (1980-2019), and MEDLINE (1980-2019) were queried for all studies describing the development of PTOA after TT or AM ACLR. Data pertaining to patient demographics, ACLR technique, and radiographic PTOA were extracted. A meta-analysis utilizing the DerSimonian-Laird method for random effects was used to compare the weighted proportion of PTOA after ACLR between the TT and AM approaches. Results: There were 16 studies identified for inclusion with a total of 1546 patients. The mean follow-up across all studies was 10.9 years (range, 5.4-17.8 years). The mean follow-up in the AM and TT groups was 10.8 years (range, 5.4-17 years) and 11.4 years (range, 6-17.8 years), respectively. A total of 783 (50.6%) patients underwent TT ACLR. Of these patients, 401 (weighted mean, 49.3%) developed radiographic PTOA. A total of 763 (49.4%) patients underwent AM ACLR. Of these patients, 166 (mean, 21.8%) went on to develop radiographic PTOA. The meta-analysis demonstrated a significantly greater rate of PTOA after ACLR using a TT technique compared with an AM technique overall (49.3% vs 25.4%, respectively; P <.001) and when studies were stratified by 5- to 10-year (53.7% vs 14.2%, respectively; P <.001) and greater than 10-year (45.6% vs 31.2%, respectively; P <.0001) follow-up. Conclusion: TT ACLR was associated with higher overall rates of radiographic PTOA compared with the AM ACLR approach. The rates of radiographic PTOA after ACLR with a TT approach were also significantly higher than using an AM approach when stratified by length of follow-up (5- to 10-year and >10-year follow-up). [ABSTRACT FROM AUTHOR]

Purpose: An understanding of the behavior of a new ACL graft in the femoral tunnel during knee motion and external loading can provide information pertinent to graft healing, tunnel enlargement, and graft failure. The purpose of the study was to measure the percentage of the tunnel filled by the graft and determine the amount and location of the graft–tunnel contact with knee motion and under external knee loads. Methods: Single bundle anatomical ACL reconstruction was performed on six cadaveric knees. Specimens were positioned with a robotic testing system under: (1) passive flexion–extension, (2) 89-N anterior and posterior tibial loads, (3) 5-N m internal and external torques, and (4) 7-N m valgus moment. The knees were then dissected, repositioned by the robot and the geometry of the femoral tunnel and graft were digitized by laser scanning. The percentage of tunnel filled and the contact region between graft and tunnel at the femoral tunnel aperture were calculated. Results: The graft occupies approximately 70% of the femoral tunnel aperture and anterior tibial loading tended to reduce this value. The graft contacted about 60% of the tunnel circumference and the location of the graft–tunnel contact changed significantly with knee flexion. Conclusion: This study found that the graft tends to rotate around the tunnel circumference during knee flexion–extension and contract under knee loading. The "windshield–wiper" and "bungee cord" effect may contribute to femoral tunnel enlargement, affect graft healing, and lead to graft failure. There can be a considerable motion of the graft in the tunnel after surgery and appropriate rehabilitation time should be allowed for graft–tunnel healing to occur. To reduce graft motion, consideration should be given to interference screw fixation or a graft with bone blocks, which may allow an earlier return to activity. [ABSTRACT FROM AUTHOR]

Abstract Background Graft malposition is a risk factor for failure of anterior cruciate ligament reconstruction. A 70° arthroscope improves visualisation of the medial wall of the lateral femoral condyle without switching portals. We investigated whether the use of this arthroscope affected the accuracy and precision of femoral tunnel placement. Methods Fifty consecutive adult patients were recruited. Following one withdrawal and two exclusions, 47 patients (30 in group 1 (70° arthroscope), 17 in group 2 (30° arthroscope)) underwent three-dimensional computed tomography imaging using a grid-based system to measure tunnel position. Results No difference was found in the accuracy or precision of tunnels (mean position: group 1 = 33.3 ± 6.0% deep–shallow, 27.2 ± 5.2% high–low; group 2 = 31.7 ± 6.9% deep–shallow, 29.0 ± 6.2% high–low; not significant). A post-hoc power analysis suggests a study of 106 patients would be required. Conclusions This pilot study suggests that tunnel position is not affected by the arthroscope used. An appropriately powered study could investigate this finding alongside other potential benefits of using a 70° arthroscope for this procedure. Trial registration ClinicalTrials.gov, NCT02816606 . Registered on 28 June 2016.

The reconstruction of a ruptured anterior cruciate ligament (ACL) is a well established procedure for repair of ACL injury. Knowledge of normal appearances, the expected postoperative changes over time, and potential acute and chronic complications of this reconstruction procedure are essential. This study illustrates the role of MRI in evaluation of ACL reconstructions and their complications. MR imaging is the modality of choice for evaluation of ACL graft reconstruction. ACL graft complications such as abnormal tunnel positioning, partial and complete graft tears, arthrofibrosis, and tunnel cysts can be reliably assessed using MRI.

Abstract Purpose To evaluate the possibility to access the anatomic femoral insertion of the anterior cruciate ligament (ACL) through trans‐tibial (TT) and trans‐portal technique, for ACL reconstruction in an independent way. To register anatomical characteristics of the TT tunnels. Methods Ten formaldehyde preserved knee anatomic articular specimens were dissected. Femoral tunnels were confectioned reproducing the original topography of the ACL. First, the femoral tunnel was made with the independent trans‐portal technique. Then, utilizing the tibial stump of the ACL and tibial guides at 45°, the TT tunnels were confectioned trying to match the previously made femoral tunnel by trans‐portal technique. Results In all specimens, match between the TT tunnel with the independent trans‐portal tunnel was achieved. Mean values for TT coronal angle was 53,0°, for transversal angle 43,3° and for distance from tunnel to joint line 2,55 cm. A horizontalization and medialization of the TT tunnels had to be made to adequately match with the femoral tunnel made by the independent trans‐portal technique. Conclusions By macroscopic anatomic and independent means, an anatomic femoral tunnel was confectioned with the TT technique matching with the anatomic femoral tunnel made in an independent way. As clinical relevance, the present study allows to anatomically assess the possibility to perform an anatomic femoral tunnel through the TT technique. Level of evidence V

Background: Transportal (TP) and all-inside techniques (AIT) are the most commonly used anterior cruciate ligament (ACL) reconstruction procedures in current clinical practice. However, there is an ongoing debate over which procedure is superior. Therefore, the purpose of this systematic review was to evaluate and compare the clinical outcomes and complications of these two techniques to propose recommendations for future application. Our primary hypothesis was that AIT is a superior ACLR technique compared to TP. Methods: A systematic literature review, using PRISMA guidelines, was conducted using PubMed, Medline, Google Scholar, and EMBASE, up to February 2021 to identify studies focusing on AIT and TP techniques of ACL reconstruction. We excluded animal experiments, cadaveric studies, retrospective studies, case reports, technical notes, and studies without quantitative data. Patients' characteristics, surgical technical features, along with postoperative follow-up and complications were extracted and reported accordingly. Methodological quality of the included studies was assessed using the Modified Coleman Methodology Score (MCMS). Results: A total of 44 studies were selected for this review, of which four were comparative studies. A total of 923 patients underwent AIT and 1678 patients underwent the TP technique for ACLR. A single semitendinosus graft was commonly used in the AIT compard to combined semitendinosus and gracilis graft in the TP group. The postoperative increase in International Knee Documentation Committee (IKDC), Lysholm, KT-1000, and Short Form-12 (physical and mental) scores were similar in the AIT group and the TP group. Contrastingly, the VAS pain score was significantly lower in the AIT group compared to the TP group. Furthermore, the pooled complication rates from all studies were similar between the two groups (AIT: 54 patients, 8.26% vs. PT: 55 patients, 6.62%). However, the four studies that prospectively compared AIT and TP techniques showed lesser complications in the AIT group than the TP group. Conclusion: Since the future trend in orthopedic surgery is toward less invasive and patients' satisfaction with good outcomes, AIT is a good alternative method considering preserving bony tissue and gracilis tendon with less post-operative pain, along with more knee flexor strength and equal outcomes compared to conventional ACL reconstruction surgery. Level of Evidence II. [ABSTRACT FROM AUTHOR]

PURPOSE OF THE STUDY The purpose of this study was to evaluate the position of tibial tunnel (TT) and femoral tunnels (FT) performed by using the anteromedial (AM) portal technique and its effect on the aperture of FT. MATERIAL AND METHODS A total 44 patients operated for anterior cruciate ligament (ACL) rupture by AM portal technique between January 2013 and July 2015, were included in this study. They were subjected to a magnetic resonance imaging of the knee to assess the FT, dimensions of the FT aperture and TT. The location of the ACL graft within the joint was compared with the intact ACL of healthy individuals. The patients were also evaluated using Lysholm and IKDC subjective scores for functional outcome. RESULTS The mean FT angle on both the coronal plane (42.88°±5.83°) and the sagittal plane (68.47°±9.57°) was significantly different from the intra-articular part of the hamstring autograft angles (74.93°±7.27° and 58.74°±4.88°, respectively) (p<0.0001). The mean distance of the FT aperture was 13.18 (±2.49) mm on vertical axis, 10.97 (±1.50) mm on the sagittal axis (p<0.0001). The difference between TT axis and the axis of the intra-articular part of autograft on both coronal (72.78°±4.67° and 74.93°±7.27°, respectively) and sagittal planes (60.12°±5.53° and 58.74°±4.88°, respectively) were not significant (p>0.05). DISCUSSION Ilingrowth et al. claimed that the FT were scattered in the very large distance and some of them were placed outside of anatomical range in the series included the cases performed with transtibial and transtibial independent techniques. In this series, in which we used a femoral guide to drill the FT at lateral femoral condyle at 2 or 10 o’clock position depended upon the site of operation, we obtained a consistent FT which is comparable with the intra-articular part of native ACL. Amano et al. found that the FT aperture enlargement was significant in the series when hamstring tendons were used as autograft, over a 6-month period. We also found a significant difference between the narrowest part of the FT (7.01 ± 1.05 mm) and its aperture (10.97 ± 1.50 mm in sagittal, 13.18 ± 2.49 mm in vertical direction). The enlargement was mainly in the vertical direction, due to the fact that the loads resulting from daily life are mostly on the horizontal plane. CONCLUSIONS The direction of intra-articular part of the ACL graft in the cases operated with the AM portal technique is significantly different from the FT direction in both the coronal and sagittal planes. The enlargement of the FT aperture is larger in the vertical axis compared to the sagittal axis. Although the long-term clinical consequences of asymmetrical enlargement of the FT aperture are not known yet, to avoid this potential risk, a technique to approximate the direction of FT to the intra-articular part of the ACL without changing the FT entry site, can be used. [ABSTRACT FROM AUTHOR]

Background: Recent studies have suggested that femoral tunnel drilling during anterior cruciate ligament (ACL) reconstruction (ACLR) with the use of a flexible reaming system through a standard anteromedial portal (AM-FR) may result in a different tunnel geometry compared with a rigid reamer through an accessory anteromedial portal with hyperflexion (AM-RR). Purpose: To summarize radiologic, anatomic, and clinical outcomes from available studies that directly compared the use of AM-FR versus AM-RR for independent femoral tunnel creation during ACLR. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search was performed using the MEDLINE (PubMed) and Web of Science databases to identify all studies that directly compared radiologic, anatomic, and clinical outcomes between the use of AM-FR and AM-RR. The literature search, data recording, and methodological quality assessment was performed by 2 independent reviewers. The outcomes analyzed included resultant ACL graft positioning and graft bending angle; femoral tunnel positioning, aperture morphology, length, and widening; posterior wall breakage; and distance from various posterolateral knee structures. Results: A total of 13 studies met the eligibility criteria for inclusion. There was no difference in femoral tunnel aperture location between techniques. There were conflicting findings among studies regarding which technique resulted in a more acute graft bending angle. One study reported greater femoral tunnel widening upon follow-up with the use of AM-FR. AM-FR produced longer and more anteverted femoral tunnels than did AM-RR. The difference in tunnel length was significant and more prominent in lesser degrees of knee flexion. With AM-FR, femoral tunnels were farther from the lateral collateral ligament and peroneal nerve, and 1 of 5 studies had fewer reports of posterior wall breakage. There has been no literature comparing the clinical or functional outcomes of these techniques. Conclusion: Although no clinical studies exist comparing AM-FR and AM-RR for femoral tunnel creation during ACLR, both systems allow for reproducible positioning of an anatomic femoral tunnel aperture. The use of AM-FR results in longer and more anteverted femoral tunnels than using AM-RR, with exit points on the lateral femur that are different but safe. Surgeons should be aware of the technical differences with each method; however, further study is needed to identify any clinically important difference that results. [ABSTRACT FROM AUTHOR]

Background: The drilling technique used to make a femoral tunnel is critically important for determining outcomes after anterior cruciate ligament (ACL) reconstruction. The 2 most common methods are the transtibial (TT) and anteromedial (AM) techniques. Purpose: To determine whether graft orientation and placement affect clinical outcomes by comparing clinical and radiological outcomes after single-bundle ACL reconstruction with the AM versus TT technique. Study Design: Systematic review; Level of evidence, 3. Methods: Articles in PubMed, EMBASE, the Cochrane Library, ISI Web of Science, Scopus, and MEDLINE were searched from inception until April 25, 2020, using the following Boolean operators: transtibial OR trans-tibial AND (anteromedial OR trans-portal OR independent OR three portal OR accessory portal) AND anterior cruciate ligament. Results: Of 1270 studies retrieved, 39 studies involving 11,207 patients were included. Of these studies, 14 were clinical, 13 were radiological, and 12 were mixed. Results suggested that compared with the TT technique, the AM technique led to significantly improved anteroposterior and rotational knee stability, International Knee Documentation Committee (IKDC) scores, and recovery time from surgery. A higher proportion of negative Lachman (P =.0005) and pivot-shift test (P =.0001) results, lower KT-1000 arthrometer maximum manual displacement (P =.00001), higher Lysholm score (P =.001), a higher incidence of IKDC grade A/B (P =.05), and better visual analog scale score for satisfaction (P =.00001) were observed with the AM technique compared with the TT technique. The AM drilling technique demonstrated a significantly shorter tunnel length (P =.00001). Significant differences were seen between the femoral and tibial graft angles in both techniques. Low overall complication and revision rates were observed for ACL reconstruction with the AM drilling technique, similar to the TT drilling technique. Conclusion: In single-bundle ACL reconstruction, the AM drilling technique was superior to the TT drilling technique based on physical examination, scoring systems, and radiographic results. The AM portal technique provided a more reproducible anatomic graft placement compared with the TT technique. [ABSTRACT FROM AUTHOR]