Tunnel Position Research Articles

Factors affecting return to play and graft re-rupture after primary ACL reconstruction in professional footballers.

Modern ACL reconstruction (ACL-R) techniques have led to improved outcomes in professional footballers. The aim of this study was to identify and assess patient, surgical and post-operative factors that affected rates and time to return to play (RTP) as well as ACL re-rupture rates. A retrospective review of consecutive ACL-R undertaken in professional footballers between 2005 and 2018. Two-hundred and thirty-two knees in 215 professional footballers (17 bilateral) were included. 205 (88.9%) were male and average age at surgery was 23.3 ± 4.4years. Two-hundred and twenty-two (96.1%) returned to professional football, with 209 (90.1%) returning to the same or higher Tegner level. Subgroup analysis revealed three factors that independently affected RTP rate: (1) Players under 25years had a higher rate of RTP (99.3% vs 90.2%. p = 0.001); (2) a subsequent operation prior to RTP decreased RTP rate from 98.2 to 89.7% (p = 0.009).; (3) undergoing meniscal surgery at ACL-R decreased RTP rate (p = 0.002). The mean time to RTP from surgery was 10.5 ± 3.6months. Factors found to increase RTP time included age under 25 (11.0 vs 9.7months, p = 0.005), recurrent effusions (11.4 vs 10.2months, p = 0.035), and medial meniscal repair at ACL-R compared to meniscectomy (12.5 vs 9.6months, p = 0.022). The surgical technique varied over the study period in relation to graft type, femoral tunnel position and addition of lateral extra-articular tenodesis (LET). Overall, the re-rupture rate was 8.2% at 2years. Patella tendon autograft in an anteromedial bundle femoral tunnel position with addition of LET has the lowest re-rupture rate (2.0%). Primary ACL-R in professional footballers yields high rates of RTP (96.1%), with 90.1% at the same level or higher, at a mean 10.5months. Patients under 25years not only had a significantly higher RTP rate, but also had a lengthier period of rehabilitation. Level IV.

Rate of Tibial Tunnel Malposition Is Not Changed by Drilling Entirely Within the Stump of Preserved Remnants During ACL Reconstruction: A Prospective Comparative 3D-CT Study.

Background:Remnant preservation during anterior cruciate ligament (ACL) reconstruction (ACLR) is controversial, and it is unclear whether the stump aids or obscures tibial tunnel positioning.Purpose/Hypothesis:The aim of this study was to determine whether the rate of tibial tunnel malposition is influenced by remnant preservation. The hypothesis was that using a remnant-preserving technique to drill entirely within the tibial stump would result in a significant reduction in tibial tunnel malposition as determined by postoperative 3-dimensional computed tomography (3D-CT).Study Design:Cohort study; Level of evidence, 2.Methods:Patients undergoing ACLR between October 2018 and December 2019 underwent surgery with a remnant-preserving technique (RP group) if they had a large stump present (>50% of the native ACL length) or if there was no remnant or if it was <50% of the native length of the ACL, they underwent remnant ablation (RA group) and use of standard landmarks for tunnel positioning. The postoperative tunnel location was reported as a percentage of the overall anteroposterior (AP) and mediolateral (ML) dimensions of the tibia on axial 3D-CT. The tunnel was classified as anatomically placed if the center lay between 30% and 55% of the AP length and between 40% and 51% of the ML length.Results:Overall, 52 patients were included in the study (26 in each group). The mean tunnel positions were 36.8% ± 5.5% AP and 46.7% ± 2.9% ML in the RP group and 35.6% ± 4.8% AP and 47.3% ± 2.3% ML in the RA group. There were no significant differences in the mean AP (P = .134) and ML (P = .098) tunnel positions between the groups. Inter- and intraobserver reliability varied between fair to excellent and good to excellent, respectively. There was no significant difference in the rate of malposition between groups (RP group, 7.7%; RA group, 11.5%; P ≥ .999).Conclusion:Drilling entirely within the ACL tibial stump using a remnant-preserving reconstruction technique did not significantly change the rate of tunnel malposition when compared with stump ablation and utilization of standard landmarks.

Influence of Graft Bending Angle on Femoral Tunnel Widening After Double-Bundle ACL Reconstruction: Comparison of Transportal and Outside-In Techniques.

Background:Previous studies have suggested that increased mechanical stress due to acute graft bending angle (GBA) is associated with tunnel widening and graft failure after anterior cruciate ligament (ACL) reconstruction. Few studies have compared the GBA between the outside-in (OI) and the transportal (TP) techniques.Purpose:To evaluate the influence of GBA on clinical outcomes and tunnel widening after ACL reconstruction with OI versus TP technique.Study Design:Cohort study; Level of evidence, 3.Methods:Included in the study were 56 patients who underwent double-bundle ACL reconstruction (n = 28 in the OI group and n = 28 in the TP group). Clinical outcomes (Lysholm, International Knee Documentation Committee, Tegner score, and knee laxity) 1 year postoperatively were evaluated. Computed tomography scans at 5 days and 1 year postoperatively were used for imaging measurements, and the femoral tunnel was divided into the proximal third, middle, and aperture sections. The GBA and cross-sectional area (CSA) were measured using image analysis software and were compared between groups. A correlation analysis was performed to determine if the GBA affected clinical outcomes or tunnel widening.Results:No significant difference was observed in clinical outcomes between the groups. The GBA of both the anteromedial (AM) and posterolateral bundles were more acute in the OI group compared with the TP group (P < .05). The CSA at the AM tunnel aperture increased significantly in the OI group (84.2% ± 64.3%) compared with the TP group (51.4% ± 36.7%) (P = .04). However, there were no differences in the other sections. In the Pearson correlation test, GBA was not correlated with tunnel widening or clinical outcomes.Conclusion:Regardless of technique, the GBA did not have a significant influence on tunnel widening or clinical outcomes. Considering a wider AM tunnel aperture, a more proximal and posterior AM tunnel position might be appropriate with the OI technique.

Study on support time of tunnel lining based on non-equilibrium evolution

According to non-equilibrium evolution stability and control theory, over force is the internal effective driving force of unrecoverable time-dependent deformation. The distribution of over force reflects the failure position and mode of tunnel. The opposite force of over force is the optimal reinforcement force to prevent unrecoverable time-dependent deformation and provides a quantitative and accurate reinforcement design method for tunnel. The plastic complementary energy (PCE) is the norm of over force. The curve of PCE versus time provides a unified quantitative criterion of real time dynamic stability evaluation of tunnel in time-dependent deformation process under various external disturbing factors. Based on the curve of PCE versus time, the stresses of lining structure in different supporting time after excavation are studied comparatively. The results show that the stress of lining structure will be very high if supporting time is too early. The surrounding rock of tunnel will be unstable due to damage evolution if supporting time is too late. There is an optimal supporting time when the stress of lining structure will not be too high and the surrounding rock will not lose stability. The curve of PCE versus time can be used to guide reinforcement design and evaluate reinforcement effect.

Study on Reinforcing Effects of FRP-PCM Method under Seismic Load

The aim of the present study is to estimate the reinforcing effects of fiber reinforced plastic (FRP) grids embedded in polymer cement mortar (PCM) shotcrete (FRP-PCM method) on tunnel linings, under the seismic load. Direct shear test was conducted to investigate the mechanical properties of bonding surfaces between the PCM concrete and concrete specimens sandwiched by a FRP layer. Numerical modelling was performed to analyze the reinforcing effects of FRP-PCM method quantitively, taking into accounts the influences of cavity position and construction method of tunnels, which could provide valuable guidance for the reinforcing of underground structures.

Higher Incidence of Post-traumatic Radiographic Osteoarthritis with Transtibial Femoral Tunnel Positioning Compared to Anteromedial Femoral Tunnel Positioning During Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis (208)

Objectives: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 to the transtibial (TT) approach; however, differences in the subsequent rates of post-traumatic osteoarthritis (PTOA) incidence are not clear. 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.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 following TT or AM ACLR. Data pertaining to patient demographics, ACLR technique, and radiographic PTOA were extracted. 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:Sixteen studies were identified for inclusion with a total of 1,546 patients. The mean follow-up across all studies was 10.9 years (range 5-17.8 years). The mean follow-up specifically in the AM and TT groups were 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 (49.3%) developed radiographic PTOA. A total of 763 (49.4%) patients underwent AM ACLR. Of these patients, 324 (mean: 21.8%) went on to develop radiographic PTOA. Meta-analysis demonstrated a significantly greater rate of PTOA following ACLR using a TT technique compared to an AM reconstruction technique overall (49.3% vs.25.4%, p<0.001) and when studies were stratified by 5-10 (53.7% vs. 14.2%, p<0.001) and at greater than 10 year (45.6 % vs. 31.2%, p<0.001) follow-up.Conclusions:Transtibial ACLR is associated with higher overall rates of radiographic PTOA compared to the AM ACLR approach. The rates of radiographic PTOA following ACLR with a TT approach are also significantly higher than using an AM approach when stratified by length of follow-up (5-10 and greater than 10-year follow-up).

Comparing the Use of Flexible and Rigid Reaming Systems Through an Anteromedial Portal for Femoral Tunnel Creation During Anterior Cruciate Ligament Reconstruction: A Systematic Review.

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.

Revision surgery for failed medial patellofemoral ligament reconstruction results in better disease-specific outcome scores when performed for recurrent instability than for patellofemoral pain or limited range of motion

Medial patellofemoral ligament reconstruction (MPFL-R) is an important treatment for recurrent patellar instability. Although complications such as redislocation, patellofemoral pain (PFP) and restricted knee range of motion have been reported, few studies have investigated the results of revision surgery for failed MPFL-R. Thus, the aim of this study was to determine the results of the tailored revision surgery after considering the cause of the reconstruction failure. Between 2015 and 2019, 28 patients (male/female 9/19; age 26.2 ± 6.4years) underwent revision surgery for failed MPFL-R. The patients were grouped into the "recurrent instability" (SG1) group and "PFP" and/or "restricted range of motion" (SG2) group. Preoperatively, the clinical data, anatomical risk factor profile, and position of the femoral MPFL tunnel were determined for each patient. The Banff Patella Instability Instrument 2.0 (BPII 2.0) and numerical analogue scale (NAS 0-10) were administered preoperatively and at the final follow-up for the subjective assessment of the PFP and knee joint function. Overall, the BPII 2.0 score improved from 28.8 ± 16.6 points preoperatively to 68.0 ± 22.7 points (p < 0.0001) postoperatively. SG1 exhibited an increase in the BPII 2.0 score from 28.9 ± 20.2 points to 75.7 ± 23 points (p < 0.0001). PFP decreased from 6.8 ± 2.4 to 1.6 ± 1.9 (p < 0.0001), while the knee joint function increased from 4.3 ± 2.5 to 8.8 ± 1.6 (p < 0.0001). In SG2, the BPII 2.0 score increased from 28.7 ± 12.6 points preoperatively to 57.7 ± 19.7 points (p = 0.0002) postoperatively and was thus significantly lower than that in SG1 (p = 0.038). The intensity of PFP decreased from 6.6 ± 3.0 preoperatively to 2.1 ± 1.9 postoperatively (p = 0.0006), while the subjective knee joint function improved from 3.2 ± 1.4 preoperatively to 7.6 ± 2.3 postoperatively (p < 0.0001). The differences between the groups were not significant. Tailored revision surgery for failed MPFL-R significantly improves the patient-reported disease-specific quality of life. The study results indicate that patients undergoing revision surgery as a consequence of patellar redislocation appear to benefit more from revision surgery than those patients undergoing revision due to postoperative PFP and/or a limited knee joint range of motion. Level IV.

Full-scale test on seismic performance of circumferential joint of shield-driven tunnel

A shield-driven tunnel is deformed along the longitudinal direction when subjected to seismic loadings; the circumferential joint is the key position of the shield-driven tunnel when such longitudinal deformation occurs. In this study, the variations of the internal forces (including both axial forces and bending moments) in the longitudinal direction of the tunnel are analyzed through a numerical method based on the longitudinal equivalent continuous model (LECM). The results show that the internal forces of the tunnel are mainly an axial force caused by longitudinal excitation, and a vertical bending moment caused by transverse excitation. Based on the stress distribution of the circumferential joint, a full-scale test is conducted, and the test results are compared with those obtained by a refined numerical model with 16 segmental rings. It is shown that the variation of the opening and bolt strain of the circumferential joint follows that of the internal force. When the tunnel is subjected to longitudinal tensile forces or bending moments, the distribution rules for the bolt stress at the position of the largest opening are essentially the same. Moreover, the distribution characteristics of the concrete strain on the segment surface at the position of the largest opening are essentially the same. The maximum tensile strain appears on the outer surface of the sleeve side segment. However, the maximum compressive strain appears on the inner surface of the hand hole side segment. The maximum principal stress and damaged plasticity of the segment generally appear near the sleeve and hand hole, and have a limited influence on the segment surface. Finally, a failure test shows that the segment becomes damaged before the bolt yield, with more severe damage occurring in the sleeve side segment.

Accuracy of transportal femoral aimer in placement of femoral tunnel during arthroscopic anterior cruciate ligament reconstruction: An observational study

Objectives: Incorrect placement of the femoral tunnel can result in failure of anterior cruciate ligament reconstruction. Several techniques have been described in literature to make accurate femoral tunnel. Although eyeballing and femoral offset aimer are commonly used, they are considered to be less accurate if used in isolation. To the best of our knowledge, no study has evaluated the use of combination of eyeballing and offset aimer to make the femoral tunnel. This study aims to evaluate the position of femoral tunnel made by combination of eyeballing and femoral offset aiming device. Materials and Methods: Post-operative radiographs of 50 patients were assessed. True anteroposterior (AP) and lateral view radiographs were used to evaluate the placement of the femoral tunnel using standard methods. The outcome was assessed and compared with the standard location of femoral tunnel as described by Harner et al. and Aglietti et al. Ease of making femoral tunnel and posterior blowout were recorded. Data analysis was performed using Statistical Package for the Social Sciences version 25 statistical analysis software. Results: In the coronal plane (AP view), the mean position of the femoral tunnel from the lateral cortex was at 35.09% ± 3.9% point. In AP plane (lateral view), the mean position of the femoral tunnel was at 80.01% ± 8.02% posteriorly along the Blumensaat’s line. None of the cases had posterior blowout and the technique was said to be easy. Conclusion: Eyeballing supplemented with transportal femoral offset aimer is an easy and accurate method of placing femoral tunnel and avoids posterior wall blowout.

Arthroscopic Triangular Fibrocartilage Complex Reconstruction Using a Palmaris Longus Tendon Graft.

Patients suffer from persistent ulnar wrist pain and distal radioulnar joint instability because of chronic triangular fibrocartilage complex (TFCC) foveal tear are treated with TFCC reconstruction. We performed an arthroscopic TFCC reconstruction using a palmaris longus tendon graft that provided a minimally invasive procedure. After confirming the TFCC foveal tear and stability between the TFCC remnant and radius, the bone tunnel was made in the ulna from the ulnar shaft to ulnar fovea. The position of the bone tunnel was checked by fluorography and arthroscopy. Curved bendable 18-gauge needles into which 3-0 nylon sutures were inserted in a loop shape were passed through the tunnel from the ulnar side, and both volar-side and dorsal-side TFCC remnants were penetrated. The nylon suture was extracted from the arthroscopic 4/5 portal, and the palmaris longus tendon graft was introduced into the joint. The graft was passed through the TFCC remnant and ulnar bone tunnel from the arthroscopic portal and fixed to the ulna using an interference screw. This procedure was indicated for TFCC foveal tears with intact radial-side TFCC remnants. If the radial-side tear and instability between the TFCC and radius coexist, this technique is contraindicated, and stabilization of both the radial and ulnar sides of the TFCC should be considered. This arthroscopic technique does not violate the distal radioulnar joint capsule, extensor carpi ulnaris tendon, or tendon sheath. In addition, it helps to stabilize the ulnar carpal complex.

How Important is the Tunnel Position in Outcomes Post-ACL Reconstruction: A 3D CT-Based Study.

Drilling the femoral and tibial tunnels at their anatomical locations are critical for good outcomes and involve seeing the footprints well. We intended to compare two techniques of drilling the tunnels and the patient-reported outcomes and knee stability of patients undergoing single bundle ACL reconstruction using 3D CT to evaluate if the tunnels were anatomical or not. Sixty single bundle ACL reconstructions were analyzed, 30 each with Technique A and B. Pre-operative and after a minimum 27month follow-up Lysholm, IKDC, Tegner score, hop test, and Lachman test were noted. 3D CT was done to classify femoral tunnels positions as being well placed, slightly or grossly misplaced and tibial tunnels as optimal or suboptimal and compared. Sixty ACL reconstructions had full follow-up with a mean follow-up of 34months. There was no significant difference between tunnel positions between the two techniques. Well-placed femoral tunnel had better Lysholm score (62.2 ± 16.2 v/s 48.5 ± 17.2, p 0.002) and IKDC score (62.5 ± 14.3 v/s 52.7 ± 15.1, p 0.012).). Those who had their surgeries within 3months of their injury had better hop test (4.4 ± 0.9 v/s 3.9 ± 1, p 0.034) and IKDC scores (62.5 ± 15.8 v/s 33.2 ± 13.8, p 0.026) as compared to those that had surgery done after 3months. Tibial tunnel positions were optimal in most cases and did not differ between the two techniques. Well-placed femoral tunnels and surgeries done within 3months of the injury produced best results.

Comparison of femoral tunnel and early curative effect analysis between arthroscopic three approach and traditional anteromedial portal for reconstruction of anterior cruciate ligament

To study the three-approach and traditional anterior medial technique to establish the femoral tunnel of position, length, and coronal angle and the early efficacy of anterior cruciate ligament reconstruction. Through retrospective research, from December 2018 to June 2019, a total of 36 patients diagnosed with simple anterior cruciate ligament tear and undergoing surgery were collected. All patients had a clear history of knee sprains and were divided into two groups. A group of 16 patients, including 11 males and 5 females, with an average age of (30.13±6.54) years and an injury time of 7 to 60 (30.19±15.78) days, three-approach technique was used to drill the femoral tunnel to reconstruct the anterior cruciate ligament. Another group of 20patients, including 15 males and 5 females, with an average age of (30.80±8.60) years, and an injury time of 7 to 60 (27.35±15.50) days, the traditional anterior medial approach was used to drill the femoral tunnel to reconstruct anterior cruciate ligament. CT 3D reconstruction technique was used to evaluate the femoral tunnel and the knee joint function was evaluated by Lysholm score of the knee joint. All patients achieved primary healing after the surgical incision. No femoral tunnel fracture, vascular and nerve damage, difficulty in graft passage during the operation, and venous thrombosis occurred. All 36 patients were followed up on an outpatient basis, with a follow up period of 9 to 15 (12.00±2.83) months. Three-dimensional CT reconstruction was used to evaluate the femoral tunnel of the patients. The position of the femoral tunnel was described using the quartile method as the three-approach group:the lower (27.83±1.97) % of the femoral condyle and the posterior (25.57±3.20) %;the traditional approach group:the lower (28.38±3.21) % of the femoral condyle and the posterior (26.23±3.20) %. Bone tunnel length, three-approach group:(35.20±5.52) mm in total length, (23.20±2.07) mm in thick bone tunnel;traditional approach group:(34.60±4.26) mm in total length, (22.56±2.50) mm in thick bone tunnel. Coronal plane angle, three-approach group:(47.93±5.98) °;traditional approach group:(41.78±6.62) °. Knee joint Lysholm score, three-approach group:48.67±4.18 before surgery;97.00±2.48 at last follow up;traditional approach group:49.75±5.33 before surgery, 97.30±2.68 at last follow up, there were significant differences before and after surgery, no significant statistical difference between two groups. The positions of the femoral tunnel drilled by the two methods were within the range of the anatomic stop of the anterior cruciate ligament, and there was no statistical difference. Compared with the traditional anterior medial approach, the coronal plane angle of the femoral tunnel drilled by the three-approach approach is relatively large, and there were no statistical differences in the length of the tunnel, the early postoperative effect of the two surgical methods, and the operation time. But the three approach has a wider and clearer vision. In addition, the knee flexion angle required for drilling the femoral tunnel during surgery is significantly smaller than that of traditional approach technology, which reduces the difficulty of surgery.

Free Hand Drilling Technique to Enhance Central Position of Tunnels in Arthroscopic Acromioclavicular Joint Fixation Using TightRope System

Acromioclavicular joint (ACJ) dislocations represent one of the most common lesions in the shoulder. Arthroscopic reduction and ACJ fixation with the button system is one of the most used techniques for displaced and unstable dislocations. Difficulties with placing the tunnels in the central and correct position of the clavicular and coracoid can occur with the use of a guide, which can result in fractures, eccentric tunnel position, cortical rupture, prolongation of surgical times with its complications as bleeding, tissue infiltration, difficult visualization, and increased risk of infection. Prior free hand central tunnel placement in the clavicle with a 3.2 mm drill helps to keep in place the pin guide over the superior cortical of coracoid with reduction of guide movement to enhance the correct position of tunnel in the coracoid process avoiding bone complications.

CT Scan Assessment of Femoral Tunnel Location in ACL Reconstruction Performed During Initial Phase of the Learning Curve

Introduction:During anterior cruciate ligament (ACL) reconstruction, femoral tunnelling is one of the most imperative stage. The success of surgical reconstructions of the ACL depends on the accurate restoration of its anatomy. The significance of the location of the hole drilled in femur has been repeatedly highlighted in ACL reconstruction. Incorrect tunnel placement is not infrequent, and even with diligent training, and aids, surgeons may still have difficulty in correctly positioning tunnels intra-operatively. Usually susceptible are surgeons in initial phase of the learning curve.Objective:To determine the susceptibility of surgeons in initial phase of learning curve while drilling femoral tunnel.Methods:All patients diagnosed with ACL rupture at a single institution between August 2018 and September 2019 were considered for the study. The surgeons who were relatively new out of their fellowship and training programmes (average of less than one years of independent practice) performed all surgical reconstructions, the number of reconstructions done independently was also taken into consideration (average of less than five independent procedures done before commencement of this study). We used anatomic free hand technique using bony and anatomic indicators as our markers, assisted by ruler, to drill femoral tunnel. Every subject had an 128 slice 3D CT-Scan done in immediate post-op period. High resolution 3-Dimensional view was created of the knee to evaluate the tunnel location. The position of the femoral tunnel was evaluated using the Bernard and Hertel quadrant method. The Femoral tunnel location was expressed in terms of its distance from the notch and posterior wall of condyle, the results were expressed in terms of percentage.Results:A net total of 32 patients were included who underwent single bundle ACL reconstruction. In our study, measurement of femoral tunnel placement was - depth 37.1% and height 24.6%, represented as percentage depth (deep to shallow (t)) and height (high to low (h)). Our results were compared with other established studies. The value of height was near to that mentioned in literature; whereas the value of depth was shallower (or distal) when compared to established literature with average location being 10.7% shallower (or distal) to anteromedial bundle insertion mentioned in study by Colombet et al and 4.8% shallower when compared to study by Zantop et al. When compared to study by Bernard and Hertel the location is 12.3% shallower. The reason for comparison with anteromedial bundle is that in single bundle anatomical reconstruction Pearle et al , Segawa et al and Simmons et al advocate it to be anteromedial.Conclusion:The surgeons in initial phase of their learning curve may be more prone to shallow (non anatomic) location of femoral tunnel during single bundle ACL reconstruction. We infer that this discrepancy in proximal (deep) to distal (shallow) orientation is due to fear of posterior wall blow out, that is the violation of the posterior femoral cortex, a known intraoperative complication in ACL reconstruction.

Intra-and interobserver reliability of determining the femoral footprint of the torn anterior cruciate ligament on MRI scans

BackgroundRe-injury rates following reconstruction of the anterior cruciate ligament (ACL) are significant; in more than 20% of patients a rupture of the graft occurs. One of the main reasons for graft failure is malposition of the femoral tunnel. The femoral origin of the torn ACL can be hard to visualize during arthroscopy, plus many individual variation in femoral origin anatomy exists, which may lead to this malpositioning. To develop a patient specific guide that may resolve this problem, a preoperative MRI is needed to identify the patient specific femoral origin of the ACL. The issue here is that there may be a difference in the reliability of identification of the femoral footprint of the ACL on MRI between different observers with different backgrounds and level of experience. The purpose of this study was to determine the intra- and interobserver reliability of identifying the femoral footprint of the torn ACL on MRI and to compare this between orthopedic surgeons, residents in orthopedic surgery and MSK radiologists.MethodsMR images of the knee joint were collected retrospectively from 20 subjects with a confirmed rupture of the ACL. The 2D (coronal, sagittal, transversal) proton-density (PD) images were selected for the segmentation procedure to create 3D models of the femurs. The center of the femoral footprint of the ACL on 20 MRI scans, with visual feedback on 3D models (as reference) was determined twice by eight observers. The intra- and interobserver reliability of determining the center of the femoral footprint on MRI was evaluated. Intraclass correlation coefficients (ICCs) were calculated for the X, Y and Z coordinates separately and for a 3D coordinate.ResultsThe mean 3D distance between the first and second assessment (intraobserver reliability) was 3.82 mm. The mean 3D distance between observers (interobserver reliability) was 8.67 mm. ICCs were excellent (> 0.95), except for those between the assessments of the two MSK radiologists of the Y and Z coordinates (0.890 and 0.800 respectively). Orthopedic surgeons outscored the residents and radiologists in terms of intra- and interobserver agreement.ConclusionExcellent intraobserver reliability was demonstrated (< 4 mm). However the results of the interobserver reliability manifested remarkably less agreement between observers (> 8 mm). An orthopedic background seems to increase both intra- and interobserver reliability. Preoperative planning of the femoral tunnel position in ACL reconstruction remains a surgical decision. Experienced orthopedic surgeons should be consulted when planning for patient specific instrumentation in ACL reconstruction.

Centrifuge modeling of normal faulting and underground tunnel in sandy soil deposit

Earthquakes of large magnitudes cause fault ruptures propagation in soil layers and lead to interactions with subsurface and surface structures. The emergence of fault ruptures on or adjacent to the position of existing tunnels cause significant damage to the tunnels. The objective of this paper is to study the interaction of an embedded tunnel within a soil layer and the soil deformations imposed upon by normal faulting. A centrifuge modeling under 80-g acceleration was conducted to investigate the rupture propagation pattern for different relative tunnel positions. Compared with the free field condition, due to tunnel and normal fault rupture interactions, focused on soil relative density and tunnel rigidity in this research, found that they can dramatically modify the rupture path depending on the tunnel position relative to the fault tip. The tunnel diverts the rupture path to its sides. This study presents the normal fault-tunnel interaction with the tunnel axis parallel to the normal fault line, to examine the changes that take place in fault rupture plane locations, the vertical displacement of the ground surface with tunnel presence and the effect of tunnel rigidity and soil density on fault tunnel interaction.

Tunnel Convergence Rate in Combined Anteromedial Portal Anterior Cruciate Ligament and Anterolateral Structure Reconstructions Is Influenced by Anterior Cruciate Ligament Knee Flexion Angle, Tunnel Position, and Direction

The goal of the present study was to evaluate a potential tunnel convergence in combined anterior cruciate ligament (ACL) reconstruction using the anteromedial portal technique and lateral extra-articular tenodesis (LET). Ten fresh frozen femora were dissected and a K-wires were inserted into the middle of the ACL stump, according to an ACL reconstruction at 110° and 140° knee flexion. ACL reconstruction at 120° and 130° was simulated. Seven K-wires with different femoral insertion sites and angulations were drilled into the lateral femoral condyle relative to the lateral epicondyle (E3: 8 mm proximal and 4 mm posterior; E1: 5 mm proximal and 5 mm anterior and E2: over-the-top position). Tunnel conflict rate was evaluated using a measuring arm and a metrology software. Drilling the femoral ACL tunnel in low knee flexion (110°-120°) significantly (P < .001) reduced the tunnel conflict rate compared to the ACL drilled in high knee flexion (130°-140°). Changing the insertion point from proximal and posterior (E3) to proximal and anterior (E1) showed a reduced tunnel conflict rate from 40 ± 21.2% to 15 ± 26% and no tunnel conflict for an ACL drilled at 110°-130° knee flexion. A possible tunnel conflict in simultaneous ACL reconstruction using the AMP technique and LET was dependent on ACL knee flexion angle, LET insertion site, and angulation. This posed the dilemma that no generally applicable LET configuration could be recommended to avoid a tunnel conflict. However, it appears that an insertion point located proximal and anterior to the lateral epicondyle results in less tunnel conflicts than an insertion point located proximal and posterior. An insertion point located proximal and anterior to the lateral epicondyle with a 30° proximal and 30° anterior angulation could reliably avoid a tunnel conflict when the ACL was drilled between 110 and 130° using a low anteromedial portal.

A newly-developed guide can create tibial tunnel at an optimal position during medial meniscus posterior root repairs

BackgroundDuring transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs), accurate tibial tunnel creation within the anatomic MM posterior root attachment seems critical. This study aimed to evaluate the tibial tunnel position created by a newly-developed Precision guide during pullout repair of MMPRTs. MethodsIn 40 patients who underwent transtibial pullout repairs, the tibial tunnel was created using the Unicorn Meniscal Root (UMR) (n = 20) or Precision guide (n = 20). Three-dimensional computed tomography images of the tibial surface were evaluated postoperatively, using Tsukada's measurement method. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines corresponding to anatomic bony landmarks. The expected anatomic center (AC) and the tibial tunnel center (TC) were evaluated using the percentage-based posterolateral location on the tibial surface. The difference in the mediolateral and anteroposterior percentage distance between the AC and TC was calculated, as was the absolute distance between the AC and TC. ResultsThe mean AC was located 77.4% posterior and 40.1% lateral. The mean TC was similar in the UMR and Precision guide groups. There was no significant difference in the mediolateral percentage distance (UMR 3.9% vs. Precision 3.6%, p = 0.405), but a significant difference was observed in the anteroposterior percentage distance (UMR 3.5% vs. Precision 2.6%, p = 0.031). The mean absolute distance between the AC and TC was 3.9 mm and 3.5 mm (UMR and Precision guide groups, respectively) (p = 0.364). ConclusionsThe new Precision guide can create tibial tunnel in an optimal and stable position during pullout repair of MMPRTs.

Establishment of near and non isometric anterior cruciate ligament reconstruction with artificial ligament in a rabbit model.

BackgroundTunnel position deicide the isometry of graft attachment in synthetic anterior cruciate ligament (ACL) reconstruction. Near-isometric tunnel position may have advantage in graft integration and knee function in ACL reconstruction (ACLR) with polyethylene terephthalate (PET) ligament. Few studies focused on tunnel position isometry when conduct ACLR with an animal model. This study aimed to establish a preclinical rabbit model of near and non isometric ACLR with PET ligament and investigate the advantage of near-isometric ACLR compared to non-isometric ACLR.MethodsNine hind limbs of rabbit were used in tunnel position study. Two femoral(anatomic, nonanatomic) tunnels and three tibial(anterior, middle, posterior) tunnels were used to measure tunnel position isometry during knee full range of motion. The tunnel position combination with minimal isometry was considered as near-isometric tunnel position. Then, 48 rabbits divided into two groups were conducted near or non isometric ACLR with PET ligament with graft fixation angle of 30° and constant tension of 5N. PET ligament isometry, range of motion(ROM) restriction, knee laxity were recorded after operation and followed up with macroscopic observation, microcomputed tomography (micro-CT) analysis, histology assessment and biomechanical test at 4 and 8 weeks postoperatively.ResultsThe tunnel combination with minimal isometry was femoral anatomic position and tibial posterior position(5.19 ​± ​1.78%) and considered as near-isometric tunnel position. ROM restriction were observed in non-isometric group (22.50 ​± ​14.14°) while none in near-isometric group. However, no ROM restriction observed at 8 weeks in both group. Knee laxity compared to contralateral knee were better in near-isometric group than non-isometric group (stable/slack/total 10/2/12 VS 3/9/12, p ​= ​0.012) at 8 weeks postoperatively. Supeiror PET ligament integration were also observed in near-isometric group through macroscopic observation, micro-CT analysis, histology assessment at both 4 and 8 weeks. The failure load in the Near-Isometric group at 8 weeks were higher than timezero reconstruction with statistical difference (156.8N ​± ​25.98N vs.102.6 ​± ​22.96N, p ​= ​0.02).ConclusionA rabbit model of ACLR based on tunnel position isometry was successfully established in this study. The near-isometric tunnel position in rabbit model was femoral anatomic position and tibial posterior position. A near-isometric ACLR with PET ligament did not cause ROM restriction and had a better graft integration and follow-up stability than non-isometric ACLR with ROM restriction.The Translational Potential of this ArticleThe study demonstrate the establishmentof near-isometric tunnel position and non-isometric tunnel position with significant difference of ROM restriction and graft-bone integration. The described tunnel positions with differential isometry in a rabbit ACLR provides a reproducible and translational small animal model and enables preclinical research between tunnel position isometry and its affection on variable grafts, graft integration and knee function.