Tunnel Angle Research Articles

Predictors of Residual Right to Left Shunt in Patients Undergoing Percutaneous Transcatheter Patent Foramen Ovale Closure: A New Clue “Inferior Vena Cava-Patent Foramen Ovale Angle”

Background: Many different devices are currently used for percutaneous patent foramen ovale (PFO) closure (pPFOc), aiming to achieve complete occlusion to prevent recurrent embolism. We aimed to reveal the association between residual right-to-left shunt (RLS) after pPFOc and baseline structural features of the PFO determined using transoesophageal echocardiography (TEE) before the procedure. Methods: This is a single-center cross-sectional study. A total of 123 patients who underwent pPFOc for cryptogenic stroke (CS) were screened, consecutively. Patients were compared based on the presence of residual RLS. The association of structural features of the PFO with residual RLS was evaluated using logistic regression analysis. Results: The procedure was successfully completed in a total of 103 patients included in the study after exclusion and 21% had significant residual RLS. During a median follow-up of 18 months, one patient died at 25 months due to malignancy, recurrent CS were observed in 5 (5%) patients, and atrial fibrillation was detected in 3 (3%) patients. No significant difference was observed in the baseline clinical characteristics and laboratory parameters among the patients. In addition to atrial septal aneurysm (ASA), aortic rim, tunnel width and length; inferior vena cava (IVC)-PFO tunnel angle was associated with residual RLS with a cut-off 11.3 (AUC: 0.786, 64% sensitivity, 87% specificity, p < 0.001). In individuals with residual RLS, longer and wider tunnel size, rudimentary aortic rim, acute IVC-PFO tunnel angle, and decreased tunnel length-left disc ratio were observed. Conclusions: IVC-PFO tunnel angle is a novel parameter and provides benefit to detect significant RLS in pPFOc patients.

Anatomic femoral tunnel and satisfactory clinical outcomes achieved with the modified transtibial technique in anterior cruciate ligament reconstruction: A systematic review and meta-analysis

BackgroundAnatomic anterior cruciate ligament (ACL) reconstruction is considered the gold standard treatment for ACL injuries because it aims to restore the knee's normal anatomy and stability, while also protecting long-term knee health. Long-term clinical and radiological outcomes after ACL reconstruction using the modified TT technique are unclear. ObjectiveTo assess the clinical and radiological outcomes following ACL reconstruction using modified transtibial (TT) techniques at a minimum 12-month follow-up. DesignA systematic review with meta-analysis. MethodsPubMed, EMBASE, Web of Science, the Cochrane Library, and MEDLINE databases were searched from the inception to December 1, 2022. PICO search strategy was used to identify studies applying modified TT techniques on patients with ACL reconstruction and a minimum follow-up of 12 months. Eligible studies were identified independently by two reviewers. We extracted data on patient demographics, surgical characteristics, patient reported outcomes including subjective evaluations and clinical outcomes. Radiological data including femoral and tibial tunnel position, femoral and tibial tunnel length, and femoral tunnel angle were also extracted. The tunnel position was evaluated using the quadrant method based on three-dimensional computed tomography (3D CT) images. The standardized mean difference (SMD) and 95 % confidence interval (CI) were calculated for clinical and radiological outcomes. ResultsSixteen studies involving 628 patients were finally included. The SMD of Lysholm (90.39; 95 % CI 83.41–97.38), IKDC (86.07; 95 % CI 79.84–92.31), and Tegner (6.15; 95 % CI 3.96–8.33) scores were considered satisfactory. The depth of the femoral tunnel showed a pooled SMD of 30.08 % (95 % CI 28.25–31.91 %), and the height showed a pooled SMD of 37.72 % (95 % CI 35.75–39.70 %). The pooled SMD for the femoral tunnel angle in the coronal plane was 48.27°(95 % CI 43.14–53.40°), and the pooled SMD for the femoral tunnel length was 33.98 mm (95 % CI 29.03–38.93 mm). ConclusionsThis investigation has shown that modified TT technique can create an anatomic femoral tunnel and maintain optimal tunnel length and angulation. Most patients had satisfactory subjective outcomes and physical examinations after ACL reconstruction using modified TT technique. This information may assist in guiding expectations of clinicians and patients following ACL reconstruction with modified TT technique.

The 45° and 60°of sagittal femoral tunnel placement in anterior cruciate ligament reconstruction provide similar knee stability.

The aim of the present study was to compare 45° and 60°of sagittal femoral tunnel angles in terms of anterior tibial translation (ATT), valgus angleand graft in situ force following anterior cruciate ligament reconstruction (ACLR). Ten porcine knees were subjected to the following loading conditions: (1) 89 N anterior tibial load at 35° (full extension), 60° and 90° of knee flexionand (2) 5 N m valgus tibial moment at 35° and 45° of knee flexion. ATTand graft in situ force of the intact anterior cruciate ligament (ACL) and ACLR were collected using a robotic universal force/moment sensor (UFS) testing system for (1) ACL intact, (2) ACL-deficient (ACLD) and (3) two different ACLR using different sagittal femoral tunnel angles (coronal 45°/sagittal 45° and coronal 45°/sagittal 60°). During the anterior tibial load, the femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° and 60° had significantly higher ATT than that of the ACL-intact knees at 60° of knee flexion (p < 0.05). The femoral tunnel angle of ACLR knees at coronal 45°/sagittal 60° had significantly lower graft in situ force than that of the ACL-intact knees at 60° and 90° of knee flexion (p < 0.05). During the valgus tibial moment, the femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° and 60° had significantly lower graft in situ force than that of the ACL-intact knees at all knee flexions (p < 0.05). The femoral tunnel angle of ACLR knees at coronal 45°/sagittal 45° provided similar ATT, valgus angleand graft in situ force to that of ACLR knees at coronal 45°/sagittal 60°. Therefore, both femoral tunnel angles could be used in ACLR, as the sagittal femoral tunnel angle does not appear to be relevant in post-operative knee stability. Not applicable.

An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction

BackgroundDuring the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches.MethodsA total of 63 knees’ 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study.ResultsIn AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach.ConclusionMarking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

Clinical Outcomes of a Novel Hybrid Transtibial Technique for Femoral Tunnel Drilling in Anterior Cruciate Ligament Reconstruction: A Large Single-Center Case Series With a Minimum 2-Year Follow-up.

A novel hybrid transtibial (HTT) approach to femoral tunnel drilling in anterior cruciate ligament reconstruction (ACLR) has been developed that circumvents the need for knee hyperflexion and orients the graft in the most anatomic position without sacrificing the tunnel length or aperture. Patients who underwent ACLR utilizing the HTT technique would achieve excellent patient-reported outcome scores and experience low rates of graft failure and reoperations. Case series; Level of evidence, 4. Patients who underwent primary ACLR at a single institution between 2005 and 2020 were retrospectively reviewed. Patients treated with the HTT, anteromedial portal (AMP), and transtibial (TT) approaches were matched based on age, sex, and body mass index ±3 kg/m2. Demographic and surgical data as well as femoral tunnel angle measurements on anteroposterior and lateral radiographs were collected for the 3 groups. However, clinical outcomes were only reported for the HTT group because of concerns of graft heterogeneity. A total of 170 patients (median age, 26.5 years [interquartile range (IQR), 18.0-35.0 years]) who underwent ACLR using the HTT approach were included. The median coronal- and sagittal-plane femoral tunnel angles were 47° (IQR, 42°-53°) and 40° (IQR, 34°-46°), respectively. The sagittal-plane femoral tunnel angles in the HTT group were significantly more horizontal compared with those in the TT group (P < .0001), whereas the coronal-plane femoral tunnel angles in the HTT group were found to be significantly more vertical compared with those in the AMP group (P = .001) and more horizontal compared with those in the TT group (P < .0001). The graft failure and reoperation rates in the HTT group at a minimum 2-year follow-up were 1.8% (3/170) and 4.7% (8/170), respectively. The complication rate was 6.5% (11/170), with the most common complication being subjective stiffness in 7 patients. The median Lysholm score was 89.5 (IQR, 79.0-98.0); the median International Knee Documentation Committee score was 83.9 (IQR, 65.5-90.8); and the median Veterans RAND 12-Item Health Survey physical and mental component summary scores were 55.0 (IQR, 52.6-55.9) and 56.2 (IQR, 49.1-59.3), respectively. ACLR using the HTT technique was associated with low graft retear and revision surgery rates and good patient-reported outcome scores at medium-term follow-up and demonstrated femoral tunnel obliquity on postoperative radiographs that correlated with optimal parameters previously reported in cadaveric and biomechanical studies.

Optimal tibial tunnel angulation for anatomical anterior cruciate ligament reconstruction using transtibial technique

Numerous studies have suggested that the primary cause of failure in transtibial anterior cruciate ligament reconstruction (ACLR) is often attributed to non-anatomical placement of the bone tunnels, typically resulting from improper tibial guidance. We aimed to establish the optimal tibial tunnel angle for anatomical ACLR by adapting the transtibial (TT) technique. Additionally, we aimed to assess graft bending angle (GBA) and length changes during in vivo dynamic flexion of the knee.Twenty knee joints underwent a CT scan and dual fluoroscopic imaging system (DFIS) to reproduce relative knee position during dynamic flexion. For the single-legged lunge, subjects began in a natural standing position and flexed the right knee beyond 90° When performing the lunge task, the subject supported the body weight on the right leg, while the left leg was used to keep the balance. The tibial and femoral tunnels were established on each knee using a modified TT technique for single-bundle ACLR. The tibial tunnel angulation to the tibial axis and the sagittal plane were measured. Considering that ACL injuries tend to occur at low knee flexion angles, GBA and graft length were measured between 0° and 90° of flexion in this study.The tibial tunnel angulated the sagittal plane at 42.8° ± 3.4°, and angulated the tibial axis at 45.3° ± 5.1° The GBA was 0° at 90° flexion of the knee and increased substantially to 76.4 ± 5.5° at 0° flexion. The GBA significantly increased with the knee extending from 90° to 0° (p < 0.001). The ACL length was 30.2mm±3.0 mm at 0° flexion and decreased to 27.5mm ± 2.8 mm at 90° flexion (p = 0.072). To achieve anatomic single-bundle ACLR, the optimal tibial tunnel should be angulated at approximately 43° to the sagittal plane and approximately 45° to the tibial axis using the modified TT technique. What's more, anatomical TT ACLR resulted in comparable GBA and a relatively constant ACL length from 0° to 90° of flexion. These findings provide theoretical support for the clinical application and the promotion of the current modified TT technique with the assistance of a robot to achieve anatomical ACLR.

The Influence of Tunnel Parameters and Graft Inclination Angle on Clinical and Radiological Outcome at Long-term Follow-up after Arthroscopic Anterior Cruciate Ligament Reconstruction.

Objective To study the influence of various tunnel parameters and graft inclination angle (GIA) on the clinical and radiological outcome after anterior cruciate ligament reconstruction (ACLR) at long-term follow-up. Methods In this retrospective study, 80 patients with isolated anterior cruciate ligament (ACL) injury treated by single bundle ACLR using bone patellar tendon bone (BPTB) and hamstring (HT) autografts were evaluated clinically and radiologically at their long-term follow-up. The study population were divided into two groups based on ideal and nonideal tunnel parameters as well as ideal and nonideal GIA. The various tunnel parameters and GIA were interpreted with clinical and radiological outcome at long-term follow-up. Results Eighty patients, 36 (45%) using BPTB and 44 (55%) using HT autografts, were available to complete the study. Patients with ideal coronal tibial tunnel angle (CTTA) and coronal femoral tunnel angle (CFTA) show superior clinical outcome (pivot shift test) than nonideal CTTA and CFTA, which was found to be statistically significant ( p -value < 0.038 and 0.024, respectively). Similarly, patients with ideal coronal tibial tunnel position (CTTP) show superior clinical outcome (International Knee Documentation Committee - IKDC objective) over nonideal CTTP ( p -value < 0.017). All other tunnel parameters and GIA were not found to have influence on clinical outcome. None of the tunnel parameters have influenced osteoarthritis (OA) change. There was no progression of OA change in the study population at long-term follow-up after ACLR. Conclusion Ideal coronal tunnel parameters produced a better clinical outcome at long-term follow-up after ACLR. There was no progression of OA change at long-term follow-up after isolated ACLR.

Robotic-assisted anatomic anterior cruciate ligament reconstruction: a comparative analysis of modified transtibial and anteromedial portal techniques in cadaveric knees.

Introduction: This study employed surgical robot to perform anatomic single-bundle reconstruction using the modified transtibial (TT) technique and anteromedial (AM) portal technique. The purpose was to directly compare tunnel and graft characteristics of the two techniques. Methods: Eight cadaveric knees without ligament injury were used in the study. The modified TT and AM portal technique were both conducted under surgical robotic system. Postoperative data acquisition of the tunnel and graft characteristics included tibial tunnel position, tunnel angle, tunnel length and femoral tunnel-graft angle. Results: The mean tibial tunnel length of the modified TT technique was significantly shorter than in the AM portal technique (p < 0.001). The mean length of the femoral tunnel was significantly longer for the modified TT technique than for the AM portal technique (p < 0.001). The mean coronal angle of the tibial tunnel was significantly lower for the modified TT technique than for the AM portal technique (p < 0.001). The mean coronal angle of the femoral tunnel was significantly lower for the AM portal technique than for the modified TT technique (p < 0.001). The AM portal technique resulted in a graft bending angle that was significantly more angulated in the coronal (p < 0.001) and the sagittal planes (p < 0.001) compared with the modified TT technique. Discussion: Comparison of the preoperative planning and postoperative femoral tunnel positions showed that the mean difference of the tunnel position was 1.8 ± 0.4mm. It suggested that the surgical navigation robot could make predictable tunnel position with high accuracy. The findings may support that the modified TT technique has benefits on femoral tunnel length and obliquity compared with AM portal technique. The modified TT technique showed a larger femoral tunnel angle in the coronal plane than the AM portal technique. Compared with the modified TT technique, the more horizontal trajectory of the femoral tunnel in the AM portal technique creates a shorter femoral tunnel length and a more acute graft bending angle.

Less Subsequent Revision Anterior Cruciate Ligament Reconstruction Following Primary Bone–Patellar Tendon–Bone Anterior Cruciate Ligament Reconstruction with Suture Tape Augmentation—A Retrospective Comparative Therapeutic Trial With 5-Year Follow-Up

To investigate patient outcomes, including revision rate, following primary bone patellar-tendon bone autograft (BPTB) anterior cruciate ligament reconstruction (ACLR) with and without suture tape augmentation (STA) in a young and active cohort. All eligible patients who received primary BPTB ACLR with a minimum of 2-year follow-up were included in this retrospective cohort study. All patients receiving STA were augmented with the same device. Patients completed the following patient-reported outcome measures (PROMs): the visual analog scale, the Single Assessment Numeric Evaluation, the Knee Injury and Osteoarthritis Outcome Score subscales, and the Tegner activity scale. Anteroposterior knee laxity was assessed using a KT-1000 arthrometer preoperatively and 1-year postoperatively. Posterior tibial slope, femoral tunnel angle, and tibial tunnel placement were calculated for all patients. Subsequent surgical interventions and return to sport (RTS) were obtained from each patient. One hundred fourteen patients (52 BPTB ACLR with STA, 62 traditional BPTB ACLR) with a mean patient age <19 years and a mean final follow-up of ≥5 years were included. Compared with the control group, the STA group demonstrated significantly less subsequent revision ACLR (0 vs. 5, P= .036). All PROMs and KT-1000 measurements improved at final follow-up (P<.001) and were comparable between groups. There were no differences seen in either posterior tibial slope or graft tunnel placement between groups. More than 85% of the patients were able to return to the sport that led to their injury at full capacity with no differences seen in RTS rate, time to RTS, or level of competition between groups. Compared with traditional BPTB ACLR, additional STA appeared to safely and effectively lead to less subsequent revision ACLR while maintaining acceptable PROMs and objective joint laxity measurements in a young and active patient population. Level III, retrospective cohort study.

The optimal tibial tunnel placement to maximize the graft bending angle in the transtibial posterior cruciate ligament reconstruction: a quantitative assessment in three-dimensional computed tomography model.

The graft bending angle created by the graft and the tibial tunnel has inevitably occurred during the transtibial posterior cruciate ligament (PCL) reconstruction. However, few studies quantitively analyzed this angle. This study aimed to (I) explore the optimal tibial tunnel placement to maximize the graft bending angle in the PCL reconstruction; (II) reveal the effect of the tibial tunnel placement on the graft bending angle. This was an in-vitro surgical simulation study based on the three-dimensional (3D) computed tomography (CT). A total of 55 patients who took CT scanning for knee injuries were selected (April 2020 to January 2022) from the local hospital database for review. The 3D knee models were established on the Mimics software based on the knees' CT data. Using the Rhinoceros software to simulate the transtibial PCL reconstruction on the 3D CT knee model. The anteromedial and anterolateral tibial tunnel approaches were simulated with different tibial tunnel angle. The graft bending angle and tibial tunnel length (TTL) with different tibial tunnel angles were quantitively analyzed. The graft bending angle in anterolateral approach with a 50° tibial tunnel angle was significantly greater than it in anteromedial approach with a 60° tibial tunnel angle (P<0.001). There was no difference of the graft bending angle between the anterolateral approach with a 40° tibial tunnel angle and the anteromedial approach with a 60° tibial tunnel angle (P>0.05). The graft bending angle showed a strong correlation with the tibial tunnel angle (for anteromedial approach: r=0.759, P<0.001; for anterolateral approach: r=0.702, P<0.001). The best-fit equation to calculate the graft bending angle based on the tibial tunnel angle was Y = 0.89*X + 59.05 in anteromedial tibial tunnel approach (r2=0.576), and was Y = 0.78*X + 80.21 anterolateral tibial tunnel approach (r2=0.493). The graft bending angle and TTL will significantly increase as the tibial tunnel angle becomes greater. Maximizing the tibial tunnel angle (50° tibial tunnel angle) in the anterolateral approach could provide the greatest graft bending angle in the PCL reconstruction. No matter how the tibial tunnel angle is changed in the anteromedial approach, using anterolateral approach might reduce the killer turn effect more effectively than using anteromedial approach.

Association Between Tunnel Position, Tunnel Angle, Graft Signal Intensity, and Graft Thickness in the Reconstructed Posterior Cruciate Ligament

Background: An appropriate tunnel position, tunnel angle, and tunnel-graft angle are important factors for maintaining the stability and mechanical properties of a posterior cruciate ligament (PCL) graft. Purpose: To evaluate the association between tunnel position, tunnel angle, graft signal intensity ratio (SIR), and graft thickness after remnant-preserving PCL reconstruction. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Included were patients who had undergone remnant-preserving single-bundle PCL reconstruction using a tibialis anterior allograft between March 2014 and September 2020 and who had minimum 12-month postoperative magnetic resonance imaging scans. Tunnel position and angle were evaluated via 3-dimensional computed tomography, and their association with graft SIR on both the femoral and the tibial sides was determined. Graft thickness and SIR at 3 areas of the graft were evaluated and compared, and their association with tunnel-graft angle was also determined. Results: Overall, 50 knees (50 patients; 43 male, 7 female) were included. The mean time to postoperative magnetic resonance imaging was 25.8 ± 15.8 months. The mean SIR of the graft’s midportion was higher compared with that of the proximal and distal portions ( P = .028 and P &lt; .001, respectively), and the SIR of the proximal portion was higher compared with that of the distal portion ( P = .002). The femoral tunnel-graft angle was more acute than the tibial tunnel-graft angle ( P = .004). A more anteriorly and distally located femoral tunnel led to a less acute femoral tunnel-graft angle ( P = .005) and a decreased SIR of the proximal portion ( P = .040), and a more laterally located tibial tunnel was associated with a less acute tibial tunnel-graft angle ( P = .024) and a reduced SIR of the distal portion ( P = .044). The mean thicknesses of the graft’s midportion and distal portion were larger than that of the proximal portion ( P &lt; .001). The SIR of the graft’s midportion was positively correlated with its thickness ( r = 0.321; P = .023). Conclusion: The SIR of the proximal portion of the graft around the femoral tunnel was higher than that of the distal portion around the tibial tunnel. An anteriorly and distally positioned femoral tunnel and a laterally positioned tibial tunnel resulted in less acute tunnel-graft angles that were associated with decreased signal intensity.

Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study.

Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients. This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected. Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference). To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal.

Poster 351: Relation Between Femoral Anterior Cruciate Ligament Tunnel Orientation and Anterolateral Ligament Tunnel Collision in a 3D-CT Model

Poster 351: Relation Between Femoral Anterior Cruciate Ligament Tunnel Orientation and Anterolateral Ligament Tunnel Collision in a 3D-CT Model

Poster 305: Hybrid Transtibial Technique for Femoral Tunnel Drilling in Anterior Cruciate Ligament Reconstruction: A Retrospective, Matched Comparison Study to Anteromedial Portal and Transtibial Approaches

Objectives: Improved biomechanical and clinical outcomes have been reported when femoral anterior cruciate ligament (ACL) tunnels are centered on the native footprint. The anteromedial portal (AMP) technique achieves improved aperture position when compared to a transtibial (TT) approach but sacrifices technical ease and creates a shorter more angulated tunnel. A hybrid transtibial technique (HTT) using medial portal guidance of a flexible transtibial guide wire may combine the strengths of both the AM and TT approaches while mitigating the technical challenges of both techniques. The purpose of our study was to evaluate the clinical efficacy of ACLR using a HTT technique for femoral tunnel drilling in comparison to matched cohorts of AMP and TT drilling approaches in terms of failure/revision requirements and patient-reported outcomes. Methods: A database consisting of all patients with isolated ACL tear and primary reconstruction at a single center between 2005 and 2020 was retrospectively reviewed. Inclusion criteria were patients age ³ 13 years at the time of index ACL reconstruction (ACLR), isolated ACL tear with/without concomitant meniscal/chondral pathology and had minimum 2 year ³ postoperative follow-up. Patients with open physes, prior surgical intervention on the ipsilateral knee, chondral pathology treated with high tibial osteotomy/distal femoral osteotomy, treated for other concurrent ligamentous pathology were excluded. Patients treated with the AMP, TT, and HTT approach meeting inclusion criteria were matched based on age ± 3 years, same sex, and body mass index (BMI) ± 3 Kg/m2. Demographical data (Table 1), surgical data, plain radiographic femoral tunnel angle measurements on anteroposterior and lateral films, postoperative complications and reoperation/revision rates, and patient reported outcome (PRO) scores were collected and reported for each of the three cohorts. Results: A total of 495 patients were included; 170 patients underwent ACLR using the HTT approach, 162 using AMP approach, and 163 using the TT approach. The most common graft of choice for HTT technique was bone patellar tendon bone (BPTB) (162/170 [95.3%]) and for AMP (131/162 [80.9%] and TT (158/163 [96.9%]) technique was hamstring (Table 2). The median (IQR) femoral tunnel angle on sagittal plane showed significant differences between HTT 40° (34°, 46°) and TT 32° (27°, 38°) cohorts ( P- value &lt; 0.0001) (Table 3). On coronal plane the median (IQR) femoral tunnel angles showed significant differences between HTT 47° (42°, 52°) and for both AMP 44° (33°, 54°) and TT 55° (47°, 60°) cohorts ( P- value: 0.001 and &lt;0.001 respectively. Recurrent ACL injury in the ipsilateral knee was experienced in 3/170 (1.8%) HTT patients, 6/162 (3.7%) AMP patients, and 6/163 (3.7%) TT patients at minimum 2-year clinical follow-up (Table 4). When patients were surveyed via phone or email questionnaires, 6/170 (7.4%) HTT, 11/163 AMP (20%), and 18/162 (24.3%) TT patients responded to having further ACLR procedures. The Knee injury and Osteoarthritis Outcome Score (KOOS) pain score and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) function and total scores were found to be statistically significant between HTT and TT technique patients. All other PRO scores showed comparable scores between HTT patients when compared with AMP and TT patients. Conclusions: Patients that underwent ACLR with HTT approach had lower failure/revision rates and comparable or better PRO scores at medium-term follow-up when compared to AMP and TT approach. [Table: see text][Table: see text][Table: see text][Table: see text]

Freehand vs. Medial Portal Offset Aimer Technique for Accurate Femoral Tunnel Placement in Arthroscopic ACL Reconstruction.

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. 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. 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. 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. The online version contains supplementary material available at 10.1007/s43465-023-00929-z.

RISK FACTORS FOR PUPILLARY OPTIC CAPTURE FOLLOWING SUTURELESS FLANGED INTRAOCULAR LENS FIXATION FOR INTRAOCULAR LENS DISLOCATION.

To identify risk factors for pupillary optic capture after sutureless flanged intraocular lens (IOL) fixation for IOL dislocation. This retrospective comparative study enrolled consecutive patients who underwent flanged IOL fixation using 25-gauge pars plana vitrectomy. One hundred twenty-six eyes (126 patients) were divided into two groups according to the presence or absence of pupillary optic capture. A swept-source anterior segment optical coherence tomography and a rotating Scheimpflug camera were used to analyze and compare surgical parameters, including axial length, anterior chamber depth, differences in scleral tunnel angle and length, and IOL tilt and decentration, between the two groups. Compared with the nonpupillary optic capture group (106 eyes, 84.1%), the pupillary optic capture group (20 eyes, 15.9%) had larger differences in the nasal and temporal scleral tunnel angles and larger horizontal tilt (P < 0.05). Multivariate regression analysis demonstrated that these factors correlated with the occurrence of pupillary optic capture (P < 0.05). To prevent pupillary optic capture after flanged IOL fixation, surgeons should avoid asymmetry in the angles of the nasal and temporal scleral tunnels, which causes horizontal IOL tilt and subsequent pupillary capture.

The tibial tunnel drilling angles of 60° provided a lower ultimate load to failure on a single bundle posterior cruciate ligament graft using interference screw fixation compared to 30°/45°.

To biomechanically compare the initial fixation strength of grafts among three tibial tunnel angles (30°/45°/60°) in transtibial posterior cruciate ligament (PCL) reconstruction. A series of transtibial PCL reconstruction models were established with porcine tibias and bovine tendons. Specimens were randomly assigned to three groups according to the angles between the tibial tunnel and the perpendicular line of the tibial shaft: Group A (30°, n = 12), Group B (45°, n = 12), and Group C (60°, n = 12). The area of the tunnel entrance, the segmental bone mineral density (sBMD) of the graft fixation site of the tibia and the maximum insertion torque of the interference screw were measured. Finally, load to failure tests were carried out on the graft-screw-tibia constructs at the same rate. Ultimate load to failure in Group C (335.2 ± 107.5 N) was significantly lower than that in Group A (584.1 ± 127.9 N, P < 0.01) and Group B (521.9 ± 95.9 N, P < 0.01). There were no significant differences between biomechanical properties of Groups A and B (n.s.). The posterior part fractures of the tibial tunnel exit occurred in eight specimens of Group C. In addition, the ultimate load was proven to be related to insertion torque (rho = 0.7, P < 0.01), sBMD (rho = 0.7, P < 0.01), and the area of the tunnel entrance (rho =-0.4, P = 0.01). The ultimate load to failure was significantly lower in tibial PCL interference screw fixation for tunnels drilled at 60° compared to 30°/45°. In addition, the ultimate load was significantly correlated with insertion torque, sBMD and the area of the tunnel entrance. Given that the load to failure of distal fixation may not be sufficient for early postoperative rehabilitation, a 60° tunnel should not be recommended to drill in tibia during PCL reconstruction.

Comparison of flow structures for vane and rod type vortex generators on a wind turbine airfoil

PurposeThe purpose of this paper is to investigate and compare the effects of rod and vane-type vortex generators for wind turbine applications. In large wind turbine rotors, an attached flow at all sections along the span direction is difficult to achieve which leads to an increase in aerodynamic losses, noise generation, and fatigue stress. Therefore, flow control strategies such as vortex generators (VGs) are beneficial to improve performance.Design/methodology/approachThe benefits of the application of rod-type vortex generators (RVGs) to control flow separation on a wind turbine airfoil are assessed numerically using computational fluid dynamics (CFD). The validation of the computational model is conducted against the experimental data available for the DU96-W-180 wind turbine airfoil equipped with 44 RVGs. In addition, a revised wind tunnel angle of attack (AoA) calibration procedure (based on CFD) is proposed that is applicable for separated flows. A comparison of the RVGs to the conventional vane-type vortex generators (VVGs) is presented for inflow velocity of 30 m/s and AoA leading to significant flow separation. A parametric evaluation of the geometric characteristics of both types of VGs is conducted to quantify the generated streamwise vortices.FindingsThe comparison of the induced flow structures and aerodynamic efficiency enhancements proves that RVGs may be used as an alternative to the more conventional VVGs applied on wind turbine blades for boundary layer separation control.Originality/valueA new type of VG (rod) has been investigated and compared against conventional VG (vanes) for wind turbine applications.

Influence of the Tibial Tunnel Angle and Posterior Tibial Slope on "Killer Turn" during Posterior Cruciate Ligament Reconstruction: A Three-Dimensional Finite Element Analysis.

This study aimed to evaluate the influence of various posterior tibial slopes (PTSs) and tibial tunnel angles (TTAs) on "killer turn" in posterior cruciate ligament (PCL) reconstruction by using three-dimensional finite element analysis (FEA). The study models were created using computed tomography images of a healthy young Asian male. Using SolidWorks, PCL grafts and tibial bone tunnels at different tibial drilling angles (30°, 45°, 60°) were developed. Anterior opening wedge high tibial osteotomy (aOW-HTO) was performed to evaluate the influence of the PTS (+8°, +4°, native, -4°, -8°). An FEA was performed utilizing the ANSYS software program. In the same PTS model, the peak of the equivalent Von Mises stress in PCL grafts decreased as the angle of the TTA increased. In the same TTA model, the peak of the Von Mises in PCL grafts decreased as the PTS angle increased. The "high-contact stress area" (contact stress greater than 10 MPa) was diminished when the TTA and PTS were increased. aOW-HTO was used to steepen the PTS, and a larger TTA may reduce the stress at the "killer turn" during PCL reconstruction. In conclusion, the study findings suggest that using aOW-HTO to steepen the PTS and a larger TTA may reduce the stress at the "killer turn" during PCL reconstruction. The usefulness and safety of this surgical procedure need to be evaluated in future clinical studies.

Biomechanical comparison of Tibial-sided supplemental fixation techniques in Bone-Patellar Tendon-Bone anterior cruciate ligament reconstruction

PurposeThe purpose of this study was to compare the biomechanical properties of a commercially available suture anchor and a screw post for supplemental tibial fixation of a bone-patellar tendon-bone (BTB) graft at time zero. We hypothesized that supplemental fixation using a suture anchor would demonstrate similar biomechanical performance in comparison with a screw post. MethodsSixteen fresh frozen, healthy human cadaveric knees underwent BTB autograft harvest, placement, and primary tibial-sided interference screw fixation using a standardized technique performed by a single surgeon. Specimens were randomly assigned to one of two tibial-sided supplemental fixation groups (suture anchor or screw post), yielding eight specimens in each group. Each specimen was affixed to a custom loading apparatus, with the tibial tunnel aligned in a vertical position that allowed for parallel “worst-case scenario” loading and eliminated loading variation due to tibial tunnel angle. Grafts were pretensioned to 30 N and biomechanical performance was compared with respect to cyclical loading between 50–250 N for 500 cycles at 0.5 Hz and pull-to-failure loading at 60 mm/min. ResultsThe suture anchor and screw post supplemental constructs demonstrated similar performance with respect to all biomechanical parameters assessed, including yield strength (294.0 N [IQR 267.2–304.2 N] versus 332.1 N [IQR 313.8–350.4 N]; P = 0.079) and ultimate strength (330.1 N [IQR 306.9–418.7 N] versus 374.7 N [IQR 362.0–387.3 N]; P = 0.3798). However, of the eight original specimens in each group, one suture anchor specimen (12.5%) and six metallic screw post specimens (75%) failed during cyclical testing and were unable to undergo displacement and load to failure testing. ConclusionThis study provides preliminary evidence that supplemental tibial-sided fixation of a BTB ACL graft with a suture anchor has similar loading characteristics or load-to-failure strength when compared to supplemental fixation with a screw post construct. Study designLaboratory Controlled Study. Level of evidenceBasic Science Study.