Tibial Aperture Research Articles

Magnetic Resonance Imaging Assessment of Hamstring Graft Healing and Integration 1 and Minimum 2 Years after ACL Reconstruction

Background: An increase has been seen in the number of studies of anterior cruciate ligament reconstruction (ACLR) that use magnetic resonance imaging (MRI) as an outcome measure and proxy for healing and integration of the reconstruction graft. Despite this, the MRI appearance of a steady-state graft and how long it takes to achieve such an appearance have not yet been established. Purpose: To establish whether a hamstring tendon autograft for ACLR changes in appearance on MRI scans between 1 and 2 years and whether this change affects a patient’s ability to return to sports. Study Design: Case series; Level of evidence, 4. Methods: Patients with hamstring tendon autograft ACLR underwent MRI and clinical outcome measures at 1 year and at a final follow-up of at least 2 years. MRI graft signal was measured at multiple regions of interest using oblique reconstructions both parallel and perpendicular to the graft, with lower signal indicative of better healing and expressed as the signal intensity ratio (SIR). Changes in tunnel aperture areas were also measured. Clinical outcomes were side-to-side anterior laxity and patient-reported outcome measures (PROMs). Results: A total of 42 patients were included. At 1 year, the mean SIR for the graft was 2.7 ± 1.2. Graft SIR of the femoral aperture was significantly higher than that of the tibial aperture (3.4 ± 1.3 vs 2.6 ± 1.8, respectively; P = .022). Overall, no significant change was seen on MRI scans after 2 years; a proximal graft SIR of 1.9 provided a sensitivity of 96% to remain unchanged. However, in the 6 patients with the highest proximal graft SIR (>4) at 1 year, a significant reduction in signal was seen at final follow-up (P = .026), alongside an improvement in sporting level. A significant reduction in aperture area was also seen between 1 and 2 years (tibial, –6.3 mm2, P < .001; femoral, –13.3 mm2, P < .001), which was more marked in the group with proximal graft SIR >4 at 1 year and correlated with a reduction in graft signal. The patients had a high sporting level; the median Tegner activity score was 6 (range, 5-10), and a third of patients scored either 9 or 10. Overall, PROMs and knee laxity were not associated with MRI appearance. Conclusion: In the majority of patients, graft SIR on MRI did not change significantly after 1 year, and a proximal graft SIR <2 was a sensitive indicator for a stable graft signal, implying healing. Monitoring is proposed for patients who have a high signal at 1 year (proximal graft SIR >4), because a significant reduction in signal was seen in the second year, indicative of ongoing healing, alongside an improvement in sporting level. A reduction in tunnel aperture area correlated with a reduction in graft SIR, suggesting this could also be a useful measure of graft integration.

A Modified Anatomic Transtibial Double-Bundle Anterior Cruciate Ligament Reconstruction Provides Reliable Bone Tunnel Positioning

PurposeTo evaluate the femoral and tibial tunnel positions via a modified anatomic transtibial double-bundle anterior cruciate ligament (ACL) reconstruction.MethodsPatients who underwent double-bundle ACL reconstruction using the transtibial tunnel creation technique were identified. Double-bundle ACL reconstruction was performed for 94 knees using the transtibial tunnel creation technique. Tunnel aperture configurations and center positions of the anteromedial (AM) and posterolateral (PL) tunnels via postoperative 3-dimensional computed tomography were evaluated.ResultsThere were 94 knees included. Regarding the intra-articular tunnel aperture configurations, the AM and PL tunnels overlapped at the femoral and tibial aperture in 66.0% and 94.7% cases, respectively. The mean femoral bone tunnel center was located at 23.0 ± 3.9% in the posterior-to-anterior ratio and 28.7 ± 6.0% in the proximal-to-distal ratio for the AM tunnels and at 32.8 ± 4.7% and 51.2 ± 5.2% for the PL tunnels, respectively. In the tibial tunnels, the mean AM tunnel center was located at 31.4 ± 3.6% in the anterior-to-posterior ratio and 44.3 ± 1.8% in the medial-to-lateral ratio and at 47.5 ± 3.8% and 44.3 ± 1.9% in the PL tunnel center, respectively. The femoral tunnels of outliers, both those created in nonanatomic positions as well as the posterior wall blowouts, were revealed in 7.4% cases. The nonanatomical bone tunnel group had significant heavier weight patients, lower tibial posterior slope, and were anterior in the AM and PL tunnel position. Posterior wall blowouts were related to posterior and proximal PL bone tunnel positions.ConclusionsModified transtibial double-bundle ACL reconstruction is a reliable tunnel creation technique with anatomic placement in 92.6% of the cases. The modification required that partially superimposing configuration of the 2 tibial tunnel apertures. The nonanatomic tunnels were related to patients of heavier weight and lower tibial posterior sloped knees, whereas the posterior wall blowouts were related to the posterior and proximal PL bone tunnel positions.Level of EvidenceLevel IV, therapeutic case series.

Increase in cartilage degeneration in all knee compartments after failed ACL reconstruction at 4\xa0years of follow-up

PurposeDegeneration of the cartilage after anterior cruciate ligament reconstruction (ACL-R) is known, and further deterioration can be expected in patients with tunnel malplacement or partial meniscal resection. It was hypothesized that there is a significant increase in cartilage degeneration after failed ACL-R.Material and methodsIsolated ACL revision surgery was performed in 154 patients at an interval of 46 ± 33 months (5–175 months) between primary and revision surgery. Cartilage status at the medial, lateral femorotibial, and patellofemoral compartments were assessed arthroscopically during primary and revision ACL-R in accordance with the Outerbridge classification. Tunnel placement, roof angle, and tibial slope was measured using anteroposterior and lateral radiographic views.ResultsCartilage degeneration increased significantly in the medial femorotibial compartment, followed by the lateral and patellofemoral compartments. There was a correlation between both cartilage degeneration in the patellofemoral compartment (PFC) (rs = 0.28, p = 0.0012) and medial tibial plateau (Rs = 0.24, p = 0.003) in relation to the position of tibial tunnel in the frontal plane. Worsening of the cartilage status in the medial femorotibial compartment, either femoral or tibial, was correlated with the tibial aperture site in the lateral view (Rs = 0.28, p < 0.001). Cartilage degeneration in the lateral compartment of the knee, on both femoral or tibial side, was inversely correlated with the femoral roof angle (Rs = −0.1985, p = 0.02). Meniscal tears, either at the medial or lateral site or at both, were found in 93 patients (60%) during primary ACL-R and increased to 132 patients (86%) during revision ACL-R.DiscussionAccelerated cartilage degeneration and high prevalence of meniscal lesions are seen in failed ACL-R. Tunnel placement showed significant impact on cartilage degeneration and may partially explain the increased risk of an inferior outcome when revision surgery is required after failed primary ACL-R.Level of evidence: Level IV—retrospective cohort study.

Primary stability of single-stage revision reconstruction of the anterior cruciate ligament in case of failure of dynamic intraligamentary stabilization depends on implant position during ACL repair

IntroductionThe object of this study was to evaluate the primary stability of tibial interference screw (IFS) fixation in single-stage revision surgery of the anterior cruciate ligament (ACL) in the case of recurrent instability after ACL repair with dynamic intraligamentary stabilization (DIS), dependent on the implant position during DIS.Materials and methodsTibial aperture fixation in ACL reconstruction (ACL-R) was performed in a porcine knee model using an IFS. Native ACL-R was performed in the control group (n = 15). In the intervention groups DIS and subsequent implant removal were performed prior to single-stage revision ACL-R. A distance of 20 mm in group R-DIS1 (n = 15) and 5 mm in group R-DIS2 (n = 15) was left between the joint line and the implant during DIS. Specimens were mounted in a material-testing machine and load-to-failure was applied in a worst-case-scenario.ResultsLoad to failure was 454 ± 111 N in the R-DIS1 group, 154 ± 71 N in the R-DIS2 group and 405 ± 105 N in the primary ACL-R group. Load-to-failure, stiffness and elongation of the group R-DIS2 were significantly inferior in comparison to R-DIS1 and ACL-R respectively (p < 0.001). No significant difference was found between load-to-failure, stiffness and elongation of R-DIS1 and the control group.ConclusionPrimary stability of tibial aperture fixation in single-stage revision ACL-R in case of recurrent instability after DIS depends on monobloc position during ACL repair. Primary stability is comparable to aperture fixation in primary ACL-R, if a bone stock of 20 mm is left between the monobloc and the tibial joint line during the initial procedure.

Tibial Tunnel Placement in ACL Reconstruction Using a Novel Grid and Biplanar Stereoradiographic Imaging.

Background:Nonanatomic graft placement is a frequent cause of anterior cruciate ligament reconstruction (ACLR) failure, and it can be attributed to either tibial or femoral tunnel malposition. To describe tibial tunnel placement in ACLR, we used EOS, a low-dose biplanar stereoradiographic imaging modality, to create a comprehensive grid that combines anteroposterior (AP) and mediolateral (ML) coordinates.Purpose:To (1) validate the automated grid generated from EOS imaging and (2) compare the results with optimal tibial tunnel placement.Study Design:Descriptive laboratory study.Methods:Using EOS, 3-dimensional models were created of the knees of 37 patients who had undergone ACLR. From the most medial, lateral, anterior, and posterior points on the tibial plateau of the EOS 3-dimensional model for each patient, an automated and personalized grid was generated from 2 independent observers’ series of reconstructions. To validate this grid, each observer also manually measured the ML and AP distances, the medial proximal tibial angle (MPTA), and the tibial slope for each patient. The ideal tibial tunnel placement, as described in the literature, was compared with the actual tibial tunnel grid coordinates of each patient.Results:The automated grid metrics for observer 1 gave a mean (95% CI) AP depth of 54.7 mm (53.4-55.9), ML width of 75.0 mm (73.3-76.6), MPTA of 84.9° (83.7-86.0), and slope of 7.2° (5.4-9.0). The differences with corresponding manual measurements were means (95% CIs) of 2.4 mm (1.4-3.4 mm), 0.5 mm (–1.3 to 2.2 mm), 1.2° (–0.4° to 2.9°), and –0.4° (–2.1° to 1.2°), respectively. The correlation between automated and manual measurements was r = 0.78 for the AP depth, r = 0.68 for the ML width, r = 0.18 for the MPTA, and r = 0.44 for the slope. The center of the actual tibial aperture on the plateau was a mean of 5.5 mm (95% CI, 4.8-6.1 mm) away from the referenced anatomic position, with a tendency toward more medial placement.Conclusion:The automated grid created using biplanar stereoradiographic imaging provided a novel, precise, and reproducible description of the tibial tunnel placement in ACLR.Clinical Relevance:This technique can be used during preoperative planning, intraoperative guidance, and postoperative evaluation of tibial tunnel placement in ACLR.

Adjustable suspension versus hybrid fixation in hamstring autograft anterior cruciate ligament reconstruction

BackgroundThere has been increased use of adjustable suspensory fixation (ASF) for anterior cruciate ligament reconstruction (ACLR). Potential benefits are the ability to use a shorter graft and to prevent graft displacement and damage. The purpose of this study was to establish the efficacy of this fixation method and assess whether it leads to less tunnel widening, and avoids known complications of screw fixation. MethodsThirty-eight patients who underwent ACLR with ASF on both the femoral and tibial sides met the inclusion criteria and were propensity matched demographically with 38 patients who underwent hybrid fixation with femoral suspensory and tibial screw and sheath. At one-year, KT-1000 knee laxity measurements were recorded and detailed MRI analysis looking at tunnel aperture widening, tunnel appearance, graft integration within the tunnels, and graft healing. ResultsMRI comparison between ASF and hybrid cohorts revealed no significant differences in graft signal or integration, and clinically there were no differences in knee laxity between cohorts (mean 1.5 mm ± 2.0 and 1.5 mm ± 2.3 (n.s.) in the ASF and hybrid fixation respectively). Significantly less aperture tibial tunnel widening (2.2 mm versus 4.4 mm, p < 0.0001) and tibial cysts (2 versus 9, p = 0.047) were observed in the ASF cohort, whilst mean femoral tunnel widening was comparable between both cohorts (ASF 2.8 mm, hybrid 3.2 mm; n.s.). ConclusionsHamstring autografts for ACLR fixed using either ASF or a hybrid fixation technique provided comparable knee stability and MRI graft signal intensity. Tibial ASF demonstrated significantly less tibial aperture widening and tunnel cyst formation when compared to screw and sheath fixation.

A CT based evaluation of femoral and tibial tunnel widening after double bundle ACL reconstruction

IntroductionAmong the postoperative phenomenon of ACL reconstruction, tunnel enlargement has been reported consistently, regardless of the technique used. It could be clinically relevant in post operative follow up and revision surgery. This study evaluated the magnitude of tibial and femoral bone tunnels enlargement after arthroscopic double-bundle anterior cruciate ligament (ACL) reconstruction by the Computed Tomography Scan. MethodsForty patients undergoing arthroscopic double-bundle ACL reconstruction using multistranded hamstring graft, were included in the study. CT scan was performed on second postoperative day and at follow-up of 6 month. Tunnels were evaluated by digitally measuring the widths, perpendicular to the long axis of the anteromedial (AM) and posterolateral (PL) tunnels, on an oblique coronal, saggital and axial plane at 3 levels: aperture, midway, and suspension point. Bony bridge thickness at aperture and minimum distance between two tunnels to anticipate communication was also computed. ResultsFemoral tunnel measurement showed statistically significant enlargement at aperture and midway. At the aperture, enlargement of AM and PL tunnel was 21.95% and 26.16% whereas at midway, enlargement was 20.05% and 24.5%. At the suspension point, enlargement was 3.97% and 7.1%. On tibial side, order of significant enlargement was midway of AM = 21.16% and PL = 31.78% followed by aperture of AM = 18.9% and PL = 28.84% and finally suspension point of AM = 17.84% and PL = 25.21%. Average bony bridge thickness at femoral and tibial aperture was 0.291 ± 0.059 and 0.231 ± 0.105 cm respectively with 10% of the patients showed merging of tunnels at aperture. ConclusionCT scan is an effective way to determine the tunnel position and enlargement after ACL reconstruction. There is a significant widening of femoral and tibial tunnels at 6 months follow-up of arthroscopic double bundle anterior cruciate ligament reconstruction. Tunnel widening could be a serious problem after double-bundle ACL reconstruction.

Lower Tibial Tunnel Placement in Isolated Posterior Cruciate Ligament Reconstruction: Clinical Outcomes and Quantitative Radiological Analysis of the Killer Turn.

Background:The “killer turn” effect after posterior cruciate ligament (PCL) reconstruction is a problem that can lead to graft laxity or failure. Solutions for this situation are currently lacking.Purpose:To evaluate the clinical outcomes of a modified procedure for PCL reconstruction and quantify the killer turn using 3-dimensional (3D) computed tomography (CT).Study design:Case series; Level of evidence, 4.Methods:A total of 15 patients underwent modified PCL reconstruction with the tibial aperture below the center of the PCL footprint. Next, 2 virtual tibial tunnels with anatomic and proximal tibial apertures were created on 3D CT. All patients were assessed according to the Lysholm score, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Tegner score, side-to-side difference (SSD) in tibial posterior translation using stress radiography, and 3D gait analysis.Results:The modified tibial tunnel showed 2 significantly gentler turns (superior, 109.87° ± 10.12°; inferior, 151.25° ± 9.07°) compared with those reconstructed with anatomic (91.33° ± 7.28°; P < .001 for both comparisons) and proximal (99° ± 7.92°; P = .023 and P < .001, respectively) tibial apertures. The distance from the footprint to the tibial aperture was 16.49 ± 3.73 mm. All patient-reported outcome scores (mean ± SD) improved from pre- to postoperatively: Lysholm score, from 46.4 ± 18.87 to 83.47 ± 10.54 (P < .001); Tegner score, from 2.47 ± 1.85 to 6.07 ± 1.58 (P < .001); IKDC sports activities score, from 19 ± 9.90 to 33.07 ± 5.35 (P < .001); and IKDC knee symptoms score, from 17.87 ± 6.31 to 25.67 ± 3.66 (P < .001). The mean SSD improved from 9.15 ± 2.27 mm preoperatively to 4.20 ± 2.31 mm postoperatively (P < .001). The reconstructed knee showed significantly more adduction (by 1.642°), less flexion (by 1.285°), and more lateral translation (by 0.279 mm) than that of the intact knee (P < .001 for all).Conclusion:Lowering the tibial aperture during PCL reconstruction reduced the killer turn, and the clinical outcomes remained satisfactory. However, SSD and clinical outcomes were similar to those of previously described techniques using an anatomic tibial tunnel.

Effect of Nearly Isometric ACL Reconstruction on Graft-Tunnel Motion: A Quantitative Clinical Study.

Background:In anterior cruciate ligament (ACL) reconstruction, minimizing the graft-tunnel motion (GTM) will promote graft-to-bone healing and avoid graft loosening or tearing as well as potential bone tunnel enlargement. A nearly isometric state of the graft can be achieved by placing the tunnel properly to theoretically gain better graft-to-bone healing. However, little clinical evidence is available to quantify the relation between GTM and tunnel position.Purpose:To find the proper zones for the femoral and tibial tunnel apertures that minimize the GTM, referred to as the “nearly isometric zone,” through use of intraoperative GTM measurement and 3-dimensional computed tomography (3D-CT).Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 100 patients were enrolled in this study. Nearly isometric ACL reconstruction was performed, and an intra-articular GTM measuring device was designed to measure and record the amplitude of GTM while the knee was flexed from 0° to 120°. Postoperatively, the patients underwent multislice CT, and the images were used to create 3D-CT models. After tibial aperture examination, 5 patients were excluded due to the divergence of tibial aperture, and therefore 95 patients remained in the study. Patients were divided into 2 groups according to whether the lateral intercondylar ridge was absent or present. The Bernard-Hertel grid coordinates (h, t) of the femoral tunnel were then quantified.Results:The maximal GTM (mGTM) was a mean ± SD of 1.06 ± 0.66 mm (range, 0.0-3.0 mm). The mGTM in patients with a lateral intercondylar ridge was significantly lower than that in patients without a lateral intercondylar ridge (0.81 ± 0.39 vs 1.59 ± 0.73 mm, respectively; P < .0001). The average h and t were 0.227 ± 0.079 and 0.429 ± 0.770, respectively. Notably, in 1 patient, the mGTM was 0 mm whereas the coordinates (h, t) of the femoral tunnel were 0.250 and 0.255. The overall GTM slowly increased before 90° but increased significantly after the knee was bent 105° (P = .010). Correlation analysis showed that the t coordiinate had significant correlation with mGTM (R = 0.581; P < .001). A gradient pattern was created to show the nearly isometric blue zone (mGTM <0.5 mm), which was found to overlap with the IDEAL (isometric, direct insertion, eccentric, anatomic, low tension-flexion pattern) position.Conclusion:A method of measuring intraoperative GTM and quantifying femoral tunnel position on postoperative 3D-CT was successfully developed. The presence of a lateral condylar ridge can significantly reduce mGTM. A nearly isometric zone was described that was consistent with the IDEAL concept.

Paradoxical tunnel enlargement after ACL reconstruction with hamstring autografts when using \u03b2-TCP containing interference screws for tibial aperture fixation- prospectively comparative study

BackgroundTibial aperture fixation with a bioabsorbable interference screw is a popular fixation method in anterior cruciate ligament reconstruction (ACLR). An interference screw containing β-tricalcium phosphate (β-TCP) to improve bony integration and biocompatibility was recently introduced. This study aims to compare the clinical outcomes and radiological results of tunnel enlargement effect between the 2 bioabsorbable fixative devices of pure poly-L-lactic acid (PLLA) interference screws and β-TCP-containing screws, for tibial interference fixation in ACLR using hamstring autografts.MethodsEighty consecutive patients who had undergone double-bundle ACLR between 2011 to 2012 were prospectively reviewed and randomly divided into two groups based on the type of tibial interference screw: 28 were assigned to the pure PLLA screw group (Group A), while the other 29 were assigned to the β-TCP-containing screw fixation group (Group B). Clinical evaluations and radiological analyses were conducted in both groups with a minimum 2- year follow-up.ResultsThere was no significant difference in subjective or objective clinical outcome between the 2 groups. In radiological analyses, the use of a β-TCP-containing screw reduced tunnel widening in the portion of the tunnel with screw engagement compared to the pure PLLA screw, while the use of a β-TCP-containing screw resulted in greater tunnel enlargement in the proximal portion of the tunnel without screw engagement than use of a pure PLLA screw.ConclusionUse of a β-TCP-containing interference screw in tibial aperture fixation reduced tunnel enlargement in the vicinity of the screw, whereas greater enlargement occurred proximal to the screw end relative to use of a pure PLLA interference screw. These paradoxical enlargements in use of β-TCP containing screws suggest that for reducing tunnel enlargement, the length of the interference screw should be as fit as possible with tunnel length in terms of using soft grafts.Level of Evidence: II, Prospectively comparative study.Trial registrationRetrospectively registered with ClinicalTrials.gov. (NCT02754674), Date of trial registration: February 10, 2016.

Not just a game – Examining the “Social Death Penalty” and its effects on affiliation motivation and hormonal parameters

To determine the in vivo dynamic graft bending angle (GBA) in anterior cruciate ligament (ACL)–reconstructed knees, correlate the angle to tunnel positions and tunnel widening, and evaluate the effects of 2 femoral tunnel drilling techniques on GBA.Patients with an isolated ACL injury undergoing reconstruction from 2011 to 2012 were included. Transportal techniques were used to create femoral tunnels. Tunnel locations were determined by 3-dimensional computed tomography. Tibiofemoral kinematics during treadmill walking and running were assessed by dynamic stereo x-ray analysis 6 months and 2 years postoperatively. The GBA was calculated from the 3-dimensional angle between the graft and femoral tunnel vectors on each motion frame. The cross-sectional areas of femoral tunnels were measured at 6 months and compared with the initial size to assess tunnel widening.A total of 54 patients were included. Use of flexible drills resulted in significantly higher GBAs during walking (80.6° ± 7.8°, P < .001) and running (80.5° ± 9.0°, P = .025) than rigid drills (walking, 67.5° ± 9.3°; running, 74.1° ± 9.6°). Their use led to greater tunnel widening of 113.9% ± 17.6%, as compared with 97.7% ± 17.5% for rigid drills (P = .003). The femoral and tibial apertures were located in similar anatomic positions in both groups, but the femoral tunnel exits were located more anteriorly (P < .001) in the flexible drill group. A higher GBA was highly correlated with anterior location of femoral exits (r = 0.63, P < .001) and moderately correlated with greater tunnel widening (r = 0.48, P < .001).High GBAs were identified during dynamic activities after anatomic ACL reconstruction with a transportal femoral tunnel drilling technique. The GBA was greater when flexible drills were used. The high bending angle resulted from the more anterior location of the femoral tunnel exits, and it correlated with early bone tunnel widening at 6 months. These results suggest that a high GBA may increase stress at the bone-graft interface and contribute to greater tunnel widening after anatomic ACL reconstruction, although the clinical impact should be further investigated.Level III, retrospective comparative study.

In Vivo Analysis of Dynamic Graft Bending Angle in Anterior Cruciate Ligament–Reconstructed Knees During Downward Running and Level Walking: Comparison of Flexible and Rigid Drills for Transportal Technique

To determine the invivo dynamic graft bending angle (GBA) in anterior cruciate ligament (ACL)-reconstructed knees, correlate the angle to tunnel positions and tunnel widening, and evaluate the effects of 2 femoral tunnel drilling techniques on GBA. Patients with an isolated ACL injury undergoing reconstruction from 2011 to 2012 were included. Transportal techniques were used to create femoral tunnels. Tunnel locations were determined by 3-dimensional computed tomography. Tibiofemoral kinematics during treadmill walking and running were assessed by dynamic stereo x-ray analysis 6months and 2years postoperatively. The GBA was calculated from the 3-dimensional angle between the graft and femoral tunnel vectors on each motion frame. The cross-sectional areas of femoral tunnels were measured at 6months and compared with the initial size to assess tunnel widening. A total of 54 patients were included. Use of flexible drills resulted in significantly higher GBAs during walking (80.6° ± 7.8°, P < .001) and running (80.5° ± 9.0°, P= .025) than rigid drills (walking, 67.5° ± 9.3°; running, 74.1° ± 9.6°). Their use led to greater tunnel widening of 113.9% ± 17.6%, as compared with 97.7% ± 17.5% for rigid drills (P= .003). The femoral and tibial apertures were located in similar anatomic positions in both groups, but the femoral tunnel exits were located more anteriorly (P < .001) in the flexible drill group. A higher GBA was highly correlated with anterior location of femoral exits (r= 0.63, P < .001) and moderately correlated with greater tunnel widening (r= 0.48, P < .001). High GBAs were identified during dynamic activities after anatomic ACL reconstruction with a transportal femoral tunnel drilling technique. The GBA was greater when flexible drills were used. The high bending angle resulted from the more anterior location of the femoral tunnel exits, and it correlated with early bone tunnel widening at 6months. These results suggest that a high GBA may increase stress at the bone-graft interface and contribute to greater tunnel widening after anatomic ACL reconstruction, although the clinical impact should be further investigated. Level III, retrospective comparative study.

The Effect of Different Sagittal Angles of the Tibial Guide on Aperture Widening of the Tibial Tunnel during Modified Transtibial Anterior Cruciate Ligament Reconstruction: A RandomizedIn VivoStudy

PurposeThe effect of sagittal plane angle of the tibial tunnel on the severity of tibial intra-articular aperture expansion caused by iatrogenic re-reaming in anterior cruciate ligament (ACL) reconstruction using a modified transtibial technique is unknown. The purpose of this study was to compare the severity of intra-articular aperture widening at different angles (40°, 45°, and 50°) of the tibial guide (TG).Materials and MethodsNinety-seven patients who underwent modified transtibial ACL reconstruction were randomly allocated to TG 40°, 45°, and 50° groups. Intra-articular tibial aperture width (TW) and tibial tunnel length (TTL) were measured intraoperatively using an arthroscopic ruler and a depth gauge.ResultsThe TG 50° group had significantly greater tibial aperture widening than the TG 40° group. There was a significant difference among TG 40°, 45°, and 50° groups and the percentage of knees with TTL <35 mm was 8%, 9% and 3%, respectively. There were 2 females with TTL <35 mm in TG 40° and 45° groups each. The average mediolateral length of the tibial plateau was 75 mm.ConclusionsThis study shows that the TG angle of 40° would reduce the severity of intra-articular aperture widening of the tibial tunnel compared to 45° or 50° in modified transtibial ACL reconstruction.

THE TIBIAL APERTURE SURFACE ANALYSIS IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION PROCESS.

The tibial tunnel aperture in the anterior cruciate ligament reconstruction is usually analyzed as an ellipse, generated as an intersection between a tibial plateau and a tibial bone tunnel. The aim of this study is to show that the tibial tunnel aperture, which utilizes 3D tibial surface bone model, differs significantly from common computations which present the tibial tunnel anterior cruciate ligament aperture surface as an ellipse. An interactive program system was developed for the tibial tunnel aperture analysis which included the real tibia 3D surface bone model generated from a series of computed tomography images of ten male patients, their mean age being 25 years. In aperture calculation, the transverse drill angle of 10 degrees was used, whereas sagittal drill angles of 40 degrees, 50 degrees and 60 degrees were used with the drill-bit diameter set to 10 mm. The real 3D and 2D tibial tunnel aperture surface projection was calculated and compared with an ellipse. According to the calculations, generated 3D aperture surfaces were different for every patient even though the same drill parameters were used. For the sagittal drill angles of 40 degrees, 50 degrees and 60 degrees, the mean difference between the projected 3D and 2D area on the tibial plateau was 19.6 +/- 5.4%, 21.1 +/- 8.0% and 21.3 +/- 9.6%, respectively. The difference between the projected 3D area on the tibial plateau and ellipse surface was 54.8 +/- 16.3%, 39.6 +/- 10.4% and 25.0 +/- 8.0% for sagittal drill angles of 40 degrees, 50 degrees and 60 degrees, respectively. The tibial tunnel aperture surface area differs significantly from the ellipse surface area, which is commonly used in the anterior cruciate ligament reconstruction analysis. Inclusion of the 3D shape of the tibial attachment site in the preoperative anterior cruciate ligament reconstruction planning process can lead to a more precise individual anatomic anterior cruciate ligament reconstruction on the tibial bone. Both tibial aperture area generated in 3D and its projection on a tibial plateau are larger than the ellipse surface; therefore, individual characteristics of each patient have to be taken into consideration.

Tibial Tunnel Placement Accuracy During Anterior Cruciate Ligament Reconstruction: Independent Femoral Versus Transtibial Femoral Tunnel Drilling Techniques

This study aimed to compare the accuracy of tibial tunnel placement using independent femoral (IF) versus transtibial (TT) techniques. Ten matched pairs of cadaveric knees were randomized so that one knee in the pair underwent arthroscopic TT drilling of the femoral tunnel and the other underwent IF drilling through an accessory medial portal. For both techniques, an attempt was made to place the femoral and tibial tunnels as close to the center of the respective anterior cruciate ligament (ACL) footprints as possible. Preoperative and postoperative computed tomography using a technique optimized for ligament evaluation allowed comparison of the anatomic ACL tibial footprint to the tibial tunnel aperture. The percentage of tunnel aperture contained within the native footprint, as well as the distance from the center of the tunnel aperture to the center of the footprint, was measured. Additionally, graft obliquity relative to the tibial plateau was evaluated in the sagittal plane. The percentage of tibial tunnel aperture contained within the native footprint averaged 71.6% ± 17.2% versus 52.1% ± 23.4% (P = .04) in the IF and TT groups, respectively. The distance from the center of the footprint to the center of the tibial tunnel aperture was 3.50 ± 1.6 mm and 4.40 ± 1.7 mm (P = .27) in the IF and TT groups, respectively. TT drilling placed 6 of 10 tunnels posterior to the center of the footprint versus 3 of 10 tunnels in IF drilling. The graft obliquity angles were 54.8° in TT specimens and 47.5° in IF specimens (P = .09). This study adds to the literature suggesting that TT drilling with an 8-mm reamer has deleterious effects on tibial tunnel aperture and position. IF drilling, which does not involve repeated reaming of the tibial tunnel, is associated with the placement of a higher percentage of the tunnel aperture within the native tibial footprint. There was not a significant difference between the IF and TT techniques in their ability to place the center of the tibial aperture near the center of the footprint or in graft obliquity. ACL reconstruction has continued to evolve in an attempt to restore the functional anatomy and biomechanical behavior of the knee. Tibial tunnel characteristics-such as location, aperture topography, and tunnel obliquity-are important factors to consider in ACL reconstruction. This study compares tibial tunnels after IF and TT techniques.

Painful pretibial pseudocyst at bioabsorbable interference screw aperture two years after anterior cruciate ligament reconstruction

We report the case of a patient with a painful subcutaneous nodule, measuring 13 mm × 17 mm, at the pretibial graft aperture site, which presented two years after a successful anterior cruciate ligament reconstruction with an autologous hamstring graft. A bioabsorbable poly-L-lactide interference screw was used for graft fixation at the tibial aperture. The patient underwent surgical excision of the lesion and curettage at the tunnel aperture. Grossly, extruded fragments of the screw and a thick pseudocapsule of surrounding tissue were excised. There was no communication between the tunnel aperture and the knee joint. The graft was also intact. Histological analysis revealed fragments of the bioabsorbable material in association with fibrous and granulomatous chronic inflammatory cells. This was consistent with a foreign body reaction. The patient subsequently recovered and resumed preinjury level of activity. To the best of our knowledge, this is the first report describing a nodular granulomatous type reaction to foreign bioabsorbable poly-L-lactide screw material subsequent to an anterior cruciate reconstruction surgery.

Primary ACL reconstruction: comparison of Achilles tendon allograft with tibial anatomical fixation and patellar tendon allograft with external aperture fixation

Purpose The purpose of this study was to compare the outcome of primary anterior cruciate ligament (ACL) reconstruction between Achilles tendon allograft with tibial anatomical bifixation and bone-patellar tendon-bone (BPTB) allograft with tibial external aperture fixation.

The Effects of Extra-articular Starting Point and Transtibial Femoral Drilling on the Intra-articular Aperture of the Tibial Tunnel in ACL Reconstruction

Background The recent emphasis on more horizontal femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstructions requires placing a femoral tunnel lower on the lateral wall of the notch. Some surgeons have advocated moving the starting point of the tibial tunnel farther medial to achieve this more horizontal tunnel. Purpose To compare tibial tunnel aperture changes with transtibial femoral tunnel drilling. Study Design Controlled laboratory study. Methods Twenty match-paired cadaveric knees (10 specimens) were randomized into 2 groups with equal right and left knee distribution. Ten of the knees underwent tibial tunnel drilling from a medial starting point (group 1), and the corresponding opposite knee of each cadaveric specimen had the tibial tunnel drilled from a central starting point (group 2). Computerized tomography (CT) with thin slices and 3-dimensional reconstruction was used to obtain the dimensions of the apertures, area of the apertures, angles of the tunnels, and location of the starting point and ending point of the tunnels. We also determined the location of the femoral tunnels in the notch for each of the groups. The 10 knees with medial starting points underwent transtibial femoral tunnel drilling and were restudied with CT to evaluate changes in tibial tunnel characteristics. The 10 knees with central starting points underwent femoral drilling from an anteromedial arthroscopic portal. Results Central tibial tunnels were slightly larger than medial tibial tunnels before femoral drilling (106.3 mm3 vs 92.4 mm3). After femoral drilling through the medial tunnels, the apertures were larger than the central tibial apertures (118.6 mm3 vs 106.3 mm3). Medial tibial tunnels resulted in an intra-articular aperture that was farther from the tibial tubercle (43.1 mm vs 16.3 mm), farther from the medial tibial plateau (38.3 mm vs 32.2 mm), and more acute in the coronal plane (50.4° vs 79.3°). Medial tibial tunnels resulted in an intra-articular aperture that was closer to the anterior edge of the tibia (22.6 mm vs 29.6 mm) but with a less acute sagittal plane angle (82.5° vs 54.5°). The average clock-face measurement on the femur was 10:40 (±14 minutes) for the medial starting point and 10:14 (±14 minutes) for the central starting point (drilled from an anteromedial arthroscopic portal) (P = .0016). Conclusion We observed significantly increased tibial aperture size and shape after transtibial femoral drilling with a medial tibial starting point. Medial tibial tunnels, compared with more central tunnels, resulted in a more acute tibial tunnel in the coronal plane and less acute tibial tunnels relative to the sagittal plane. Medial tibial tunnels started farther from the tibial tubercle but ended farther from the medial joint line and closer to the anterior edge of the tibia in comparison to central tunnels Clinical Relevance Femoral tunnel placements may be best accomplished using a technique other than transtibial drilling through a medial tibial tunnel. Tibial tunnel angle, intra-articular position, and femoral tunnel placement are affected by the choice of extra-articular starting position.

Tibial aperture bone disruption after retrograde versus antegrade tibial tunnel drilling: a cadaveric study

The purpose of this study is to compare the local microfracture effects of antegrade versus retrograde drilling of the tibial tunnel in ACL reconstruction. Arthroscopic ACL excision was performed on eight matched cadaveric knees. Arthroscopic guided tibial tunnel reaming was performed in either an antegrade (four) or retrograde (four) direction. A 3 x 3 cm section of proximal tibial surrounding the tibial aperture was removed with open dissection, and each section underwent micro-computed tomography analysis. Three musculoskeletal radiologists graded the specimens for bone aperture disruption and discrete fracture lines. Tibial aperture irregularity was seen in all four of the antegrade specimens (mean, Grade 1.5), and in none of the retrograde specimens. Discrete fracture lines were present in all four antegrade specimens (mean 10.13 mm depth; 8.95 mm length). No fracture lines were seen in the retrograde group. Retrograde drilling of the tibial tunnel in ACL reconstruction results in less microfracture trauma to the surrounding aperture bone. The use of retrograde drilling in ACL reconstruction may decrease synovialization of the graft-tissue interface when compared to antegrade drilling.

Reducing the “Killer Turn” in Posterior Cruciate Ligament Reconstruction by Fixation Level and Smoothing the Tibial Aperture

The aim of this study was to evaluate the influence of the operative technique on reducing the so called "killer turn" at the tibial bone tunnel exit in posterior cruciate ligament (PCL) reconstruction. We investigated the benefit of reducing the sharp edge of the tibial bone tunnel exit using a custom made rasp in combination with extracortical and aperture (interference screw) graft fixation. Grafts were fixed in a porcine tibia model. Ten reconstructions each (sharp and rounded edge) were cyclically loaded (2,000 times) between 50 and 150 N, and another 10 each were subjected to 2,000 cycles between 50 and 300 N force. The surviving PCL reconstructions were loaded to failure using a material testing machine. Being subjected to the sharp edge of the posterior tibia, 5 of 10 extracortical and 8 of 10 aperture fixed grafts survived cyclic loading between 50 and 150 N. All extracortical fixed and 8 of 10 aperture fixed grafts failed before 2,000 cycles when loaded between 50 and 300 N. Structural properties of grafts fixed with interference screw were statistically significant higher when compared to extracortical fixation. After rounding the sharp edge of the tunnel, all grafts survived cycles between 50 and 150 N and 6 out of 10 extracortical and 8 of 10 aperture fixed grafts survived 2,000 cycles between 50 and 300 N. The results of this study suggest that a rounded posterior aspect of the tunnel exit at the tibial tunnel exit leads to significant less graft damage when compared to the typical sharp edge of the bone tunnel exit ("killer turn"). Additionally, the results show that aperture fixation of soft tissue grafts in PCL reconstruction is superior when compared to an extracortical fixation site. Aperture fixation and a rounded tibial bone tunnel exit seem to be a reasonable alternative in PCL reconstruction.