The Transtibial Research Articles

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.

Failure modes after anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

The reason for graft failure after anterior cruciate ligament reconstruction (ACLR) is multifactorial. Controversies remain regarding the predominant factor and incidence of failure aetiology in the literature. This review aimed to provide a meta-analysis of the literature to evaluate the relative proportion of various failure modes among patients with ACLR failure. The PubMed, Embase, Cochrane Library, Web of Science, and EBSCO databases were searched for literature on ACLR failure or revision from 1975 to 2021. Data related to causes for ACLR surgical failure were extracted, and a random effects model was used to pool the results, which incorporates potential heterogeneity. Failure modes were compared between different populations, research methods, graft types, femoral portal techniques, and fixation methods by subgroup analysis or linear regression. Funnel plots were used to identify publication bias and small-study effects. A total of 39 studies were analyzed, including 33 cohort studies and six registry-based studies reporting 6578 failures. The results showed that among patients with ACLR failure or revision, traumatic reinjury was the most common failure mode with a rate of 40% (95% CI: 35-44%), followed by technical error (34%, 95% CI: 28-42%) and biological failure (11%, 95% CI: 7-15%). Femoral tunnel malposition was the most common cause of the technical error (29%, 95% CI: 18-41%), with more than two times higher occurrence than tibial tunnel malposition (11%, 95% CI: 6-16%). Traumatic reinjury was the most common factor for ACLR failure in European populations and in recent studies, while technical errors were more common in Asian populations, earlier studies, and surgery performed using the transtibial (TT) portal technique. Biological factors were more likely to result in ACLR failure in hamstring (HT) autografts compared to bone-patellar tendon-bone (BPTB) autografts. Trauma is the most important factor leading to surgical failure or revision following ACLR. Technical error is also an important contributing factor, with femoral tunnel malposition being the leading cause of error resulting in failure.

MRI signal intensity of anterior cruciate ligament graft after transtibial versus anteromedial portal technique (TRANSIG): A randomised controlled clinical trial

BackgroundTwo primary surgical femoral drilling techniques are used to reconstruct the anterior cruciate ligament (ACL): the transtibial (TT) technique and the anteromedial portal (AMP) technique. Currently there is no consensus on which surgical technique elicits the best clinical and functional outcomes. MRI-derived measures of the signal intensity (SI) of the ACL graft have been described as an independent predictor of graft properties. The purpose of this study was to assess MRI-derived SI measurements of the ACL graft one year after ACL reconstruction, in order to compare graft maturation of both AMP and TT ACL reconstruction techniques. MethodsThis randomised controlled trial included 33 patients admitted for primary unilateral ACL reconstruction. Primary outcome was MRI Signal intensity ratio (SIR) of the ACL graft one year after ACL reconstruction. Differences in MRI SIR were assessed on two MRI sequencies: sagittal Proton Density Turbo Spin Echo weighted images (PDTSE) and 3D T2 Gradient Echo (T2*) weighted images. Analysis of interobserver and intraobserver variability was conducted for the SIR measurements. ResultsNo difference in signal intensity of the graft was found between the TT and AMP techniques one year after ACL reconstruction (PDTSE p = 0.665, T2* p = 0.957). Both interobserver and intraobserver variability showed strong agreement (ICC 0.64–0.94). ConclusionNo differences in signal intensity of the graft on MRI were seen between the femoral drilling techniques one year after ACL reconstruction, suggesting similar graft maturation at that time. Follow-up studies are needed to determine whether graft intensity changes in the long term. Level of evidenceTherapeutic study with level of evidence I.

Influence of the Anteromedial Portal and Transtibial Drilling Technique on Femoral Tunnel Lengths in ACL Reconstruction: Results Using an MRI-Based Model.

Background:In anatomic anterior cruciate ligament (ACL) reconstruction, graft placement through the anteromedial (AM) portal technique requires more horizontal drilling of the femoral tunnel as compared with the transtibial (TT) technique, which may lead to a shorter femoral tunnel and affect graft-to-bone healing. The effect of coronal and sagittal femoral tunnel obliquity angle on femoral tunnel length has not been investigated.Purpose:To compare the length of the femoral tunnels created with the TT technique versus the AM portal technique at different coronal and sagittal obliquity angles using the native femoral ACL center as the starting point of the femoral tunnel. The authors also assessed sex-based differences in tunnel lengths.Study Design:Descriptive laboratory study.Methods:Magnetic resonance imaging scans of 95 knees with an ACL rupture (55 men, 40 women; mean age, 26 years [range, 16-45 years]) were used to create 3-dimensional models of the femur. The femoral tunnel was simulated on each model using the TT and AM portal techniques; for the latter, several coronal and sagittal obliquity angles were simulated (coronal, 30°, 45°, and 60°; sagittal, 45° and 60°), representing the 10:00, 10:30, and 11:00 clockface positions for the right knee. The length of the femoral tunnel was compared between the techniques and between male and female patients.Results:The mean ± SD femoral tunnel length with the TT technique was 40.0 ± 6.8 mm. A significantly shorter tunnel was created with the AM portal technique at 30° coronal/45° sagittal (35.5 ± 3.8 mm), whereas a longer tunnel was created at 60° coronal/60° sagittal (53.3 ± 5.3 mm; P < .05 for both). The femoral tunnel created with the AM portal technique at 45° coronal/45° sagittal (40.7 ± 4.8 mm) created a similar tunnel length as the TT technique. For all techniques, the femoral tunnel was significantly shorter in female patients than male patients.Conclusion:The coronal and sagittal obliquity angles of the femoral tunnel in ACL reconstruction can significantly affect its length. The femoral tunnel created with the AM portal technique at 45° coronal/45° sagittal was similar to that created with the TT technique.Clinical Relevance:Surgeons should be aware of the femoral tunnel shortening with lower coronal obliquity angles, especially in female patients.

Freehand Anatomic Transtibial Single-Bundle Anterior Cruciate Ligament Reconstruction

Creation of the femoral tunnel for single-bundle anterior cruciate ligament (ACL) reconstruction has a high rate of nonanatomic placement with the transtibial (TT) technique but yields better restoration with the anteromedial portal technique and close restoration of the anatomic femoral footprint with the outside-in technique. Modifications of the traditional (TT) technique have been described to restore the native femoral ACL footprint and to simulate double-bundle reconstruction. Modified TT techniques try to capture the anatomic femoral footprint through an anatomic tibial tunnel. In the technique described in this article, the anatomic femoral footprint is drilled first by the use of a 2.5-mm Kirschner wire through the parapatellar anteromedial portal, making an angle 30° to the sagittal plane and 20° to the horizontal plane. The wire is drilled while the knee is hyperflexed and then withdrawn from outside until its distal end reaches the intercondylar notch. The wire is then advanced in an antegrade manner while the knee is flexed 90° until it reaches the center of the marked tibial footprint. The angle of knee flexion may be slightly increased or decreased around 90° with or without slight internal rotation to capture the anatomic tibial footprint. The procedure is completed as a TT single-bundle ACL reconstruction.

Hybrid Transtibial Femoral Preparation for Transphyseal Anterior Cruciate Ligament Reconstruction: A Radiographic Comparison With the Transtibial and Anteromedial Portal Techniques.

Background:Transphyseal anterior cruciate ligament (ACL) reconstruction remains the most commonly used technique for pubescent patients. The transtibial (TT) drilling technique creates vertical and central femoral tunnels to minimize the physeal area of injury at the expense of a nonanatomic femoral tunnel. The hybrid TT (HTT) technique offers the potential of an anatomic femoral position with tunnel geometry similar to that using the TT technique.Purpose/Hypothesis:The purpose was to perform a radiographic comparison of the HTT technique with TT and anteromedial portal (AM) techniques in adolescent patients undergoing transphyseal ACL reconstruction. It was hypothesized that femoral tunnels created during HTT would be similar to TT tunnels but significantly more vertical and central than AM tunnels.Study Design:Cohort study; Level of evidence, 3.Methods:We retrospectively screened primary transphyseal ACL reconstructions performed in adolescents at our institution between 2013 and 2019. The youngest 20 eligible patients were selected from each technique cohort: TT, AM, and HTT. Postoperative radiographs were assessed for the coronal femoral tunnel angle, as well as the location of the tunnel-physis penetration on the anteroposterior and lateral views. Physeal lesion surface area was calculated. Data were compared among the 3 groups using 1-way analysis of variance followed by pairwise comparisons.Results:Included were 47 patients with a mean ± SD age of 14.3 ± 1.2 years (n = 9 with TT, 18 with AM, and 20 with HTT techniques). The coronal tunnel angle was significantly more vertical in the TT (60.7° ± 7.2°) and HTT (54.4° ± 5.7) groups as compared with the AM group (48.8° ± 5.9; P = .0037 and P = .02, respectively). There was no significant difference between the TT and HTT groups (P = .066). The only significant finding regarding femoral tunnel location was that the HTT tunnels (28.9% ± 4.8%) penetrated the physis more centrally than did the AM tunnels (20.0% ± 5.1%; P = .00002) on lateral radiographs.Conclusion:The HTT technique presents an option for transphyseal ACL reconstruction, with femoral tunnel obliquity and estimated physeal disruption similar to that of the TT technique and significantly less than that of the AM technique. The HTT technique also results in the most central physeal perforation of all techniques, predominantly in the sagittal plane.

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).

Clinical and Radiological Outcomes of Anteromedial Portal Versus Transtibial Technique in ACL Reconstruction: A Systematic Review

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

Higher Incidence of Radiographic Posttraumatic Osteoarthritis With Transtibial Femoral Tunnel Positioning Compared With Anteromedial Femoral Tunnel Positioning During Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

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

Similar outcomes and satisfaction after transtibial versus transportal femoral drilling for anterior cruciate ligament reconstruction in young adult recreational athletes.

Controversy continues regarding whether the transtibial (TT) and transportal (TP) methods for anterior cruciate ligament (ACL) reconstruction provide similar or different outcomes, and the evidence on patient satisfaction is very limited. The objective of this study was to compare functional outcomes and patient satisfaction in young adult recreational athletes who underwent arthroscopic hamstring ACL reconstruction using either the TT or the TP femoral tunnel drilling method. A nonrandomized prospective study was designed to compare the outcomes of arthroscopic hamstring ACL reconstruction using TT or TP method. Functional outcome was assessed with the Lyshom score, and patient satisfaction with a 5-point Likert scale. Knee stability was measured with the KT-1000 arthrometer. 42 patients in the TT group and 41 in TP group, with age ranged 18-40years, were compared with a mean follow-up of 42 (range 24-60) months. There were no significant differences between groups in the Lysholm score (n.s.), sport return rate (n.s.) or patient satisfaction with the surgery (n.s.). Satisfaction was only significantly associated with the Lysholm score (OR 1.3; IC 95% 1.06-1.6; p = 0.012), but not with the return to sports (n.s.) or knee anterior laxity (n.s.). This study showed no statistical differences between the TT and the TP method in functional outcomes or patient satisfaction in young adult recreational athletes. In those patients, satisfaction with the surgery was not influenced by the return to sport activities. This study can guide surgeons in the decision-making for ACL reconstruction in recreational athletes. Level II.

ACL Reconstruction Graft Angle and Outcomes: Transtibial vs Anteromedial Reconstruction.

The importance of creating an anatomic anterior cruciate ligament (ACL) reconstruction has been receiving significant attention. The best technique by which to achieve this anatomic reconstruction continues to be debated. The two most common methods are the transtibial (TT) and anteromedial (AM) techniques. Each has its advantages and disadvantages, and the literature comparing the two remains uncertain. In this prospective comparative study, we aimed to compare the ACL graft and tunnel angles achieved using the anatomic transtibial (TT) and anteromedial (AM) techniques; compare the ACL graft and tunnel angles in knees that have undergone ACL reconstruction and knees with intact ACLs; and determine whether differences in the graft or tunnel angle produce differences in clinical outcomes, as measured using both physical exam and patient-reported outcomes, after ACL reconstruction. Patients who underwent primary ACL reconstruction with bone-tendon-bone grafts using a TT or AM technique were included. Femoral graft angle (FGA), tibial graft angle (TGA), and sagittal orientation of the reconstructed ACL and contralateral native ACL were measured on post-operative magnetic resonance imaging. Post-operatively, patients underwent measurement of knee stability and completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) survey. Twenty-nine patients were enrolled (AM group, 14; TT group, 15); at follow-up, KOOS data were available for 26 patients (13 in each group). There were no differences in sagittal ACL graft angle between groups or in comparison with the normal knee. The FGA was more vertical after TT reconstructions; the TGA was comparable between groups. There were no significant differences in 2-year post-operative physical exam measurements or in KOOS scores. Anatomic ACL angle was restored after reconstruction with both the TT and AM techniques, despite different FGAs. No significant differences in clinical outcome were noted between groups on physical exam or KOOS at 2years after surgery. These results suggest that TT reconstruction results in a graft position similar to that seen in AM reconstruction and that the location of the intra-articular tunnel aperture matters more than the orientation of the tunnel.

Femoral Tunnel Drilling Method: Risk of Reoperation and Revision After Anterior Cruciate Ligament Reconstruction

Background: The femoral tunnel in anterior cruciate ligament reconstruction (ACLR) can be created by the transtibial (TT) or tibial-independent (TI) methods. An anatomically located femoral tunnel can be more consistently achieved by TI methods, which include the anteromedial portal and lateral (outside-in, retrodrill) techniques. Nonanatomic graft placement in ACLR can result in postoperative instability and meniscal or chondral injury. An anatomically located graft is subjected to higher postoperative physiologic forces than one placed nonanatomically. Purpose: To examine isolated primary ACLR and determine the risk of aseptic revision and reoperation based on femoral tunnel drilling method. Study Design: Cohort study; Level of evidence, 2. Methods: The ACLR registry of an integrated US health care system was used to identify primary isolated unilateral ACLRs from 2009 to 2014. Multivariable Cox proportional hazard regression models were used to evaluate risk for aseptic revision for graft failure and aseptic reoperation for meniscal or chondral injury according to femoral tunnel drilling method: TI versus TT. Models included age, sex, body mass index (BMI), race, graft type, and femoral fixation type as covariates. Results: The cohort included 19,059 patients with primary ACLR. The mean age was 28.9 years (SD, 11.5), 6991 patients (36.8%) were younger than 22 years, 11,795 patients (61.9%) were male, 7648 patients (40.1%) had a BMI less than 25 kg/m2, 8913 patients (46.8%) were white, and 7357 patients (38.6%) received an allograft. Median follow-up was 2.30 years (interquartile range, 1.08-3.77). TI techniques were used for 12,342 (64.8%) of the ACLRs, and the TT method was used for 6717 (35.2%). Use of TI techniques increased from 33.6% of all ACLRs in 2009 to 83.4% in 2014. After adjustment for covariates, the TI group had a higher risk for aseptic revision than the TT group (hazard ratio [HR], 1.28; 95% CI, 1.04-1.56), and this risk was 1.41 times higher in patients younger than 22 years specifically. The 5-year cumulative reoperation probability was lower in the TI group (4.50%; 95% CI, 3.78%-5.36%) compared with the TT group (5.06%; 95% CI, 4.31-5.94%). After adjustment for the covariates, no difference in risk for aseptic reoperation was observed (HR, 1.08; 95% CI, 0.85-1.39). Conclusion: In the largest known study of its type examining femoral tunnel drilling method for primary ACLR, after adjustment for age, sex, BMI, race, graft type, and femoral fixation, TI techniques were found to carry higher risk of aseptic revision compared with the TT method, while no difference was observed in risk for aseptic reoperation.

Femoral tunnel widening is similar between anteromedial portal and transtibial techniques following single-bundle anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

In anterior cruciate ligament (ACL) reconstruction, there is concern regarding the potential risk of femoral tunnel widening in the anteromedial portal (AMP) technique due to the acute graft-bending angle at the aperture and the more elliptical aperture shape of the femoral tunnel compared to the transtibial (TT) techniques. Therefore, the aim of the current systematic review and meta-analysis was to compare the femoral tunnel widening between the AMP and TT techniques in patients who underwent ACL reconstruction. It should be included the studies that reported on femoral tunnel widening in patients who underwent single-bundle ACL reconstruction, using soft-tissue tendon graft, with AMP and/or TT techniques. Two reviewers independently recorded data from each study, including the sample size and magnitude of tunnel widening after ACL reconstruction. Twenty-one studies were finally included in this meta-analysis. The pooled changes of absolute millimeters of tunnel widening from the immediate postoperative status to the last follow-up did not differ significantly between the AMP and TT techniques at both the aperture [3.31mm, 95% confidence interval (CI) 1.7-5.0. mm versus 2.9mm, 95% CI 2.4-3.4mm, P = n.s.] and the midportion (3.5mm, 95% CI 0.8-6.3mm versus 3.0mm, 95% CI 2.2-3.9mm, P = n.s.) of the femoral tunnel. No significant difference was observed between the two techniques in the relative percentage of femoral tunnel widening (AMP; 28.8%, 95% CI 14.8-42.9% vs. TT; 29.7%, 95% CI 15.6-43.7%, P = n.s.). No significant difference in femoral tunnel widening was observed between the AMP and TT techniques, both in absolute millimeter and relative percentage, in patients who underwent single-bundle ACL reconstruction. This finding could alleviate the potential concerns associated with femoral tunnels being wider for the AMP than for the TT technique. III.

Better rotational control but similar outcomes with the outside-in versus the transtibial drilling technique for anterior cruciate ligament reconstruction: a systematic review of comparative trials.

This study was a systematic review comparing the clinical outcomes of using the transtibial (TT) versus the outside-in (OI) technique for anterior cruciate ligament (ACL) reconstruction. A comprehensive literature search was conducted using multiple databases, including Medline, Embase, and Cochrane. All databases were searched from the earliest records through August 2017 using the following Boolean operators: transtibial AND (outside-in OR out-in OR two incisions) AND anterior cruciate ligament. All prospective and retrospective controlled trials were retrieved that directly compared physical examination and knee function scores and patient-rated outcomes between the TT and OI techniques. Four prospective and three retrospective articles were identified by the search, and the findings suggested that the OI was superior to the TT technique for preparing the femoral tunnel based on the pivot shift test (p = 0.05). There was no statistically significant difference between the two treatment groups in International Knee Documentation Committee (IKDC) grades, IKDC scores, Lysholm scores, Tegner scores, or the Lachman test. No statistically significant differences were found in clinical functional results when comparing patients who underwent ACL reconstruction with the TT or OI techniques. However, the OI technique was found to be advantageous in conferring increased rotational stability as revealed by the pivot shift test. Additional studies with larger sample sizes are needed to make more precise conclusions. Therapeutic study (systematic review), Level III.

Anterolateral rotatory instability in vivo correlates tunnel position after anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft.

AIMTo quantitatively assess rotatory and anterior-posterior instability in vivo after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BTB) autografts, and to clarify the influence of tunnel positions on the knee stability.METHODSSingle-bundle ACL reconstruction with BTB autograft was performed on 50 patients with a mean age of 28 years using the trans-tibial (TT) (n = 20) and trans-portal (TP) (n = 30) techniques. Femoral and tibial tunnel positions were identified from the high-resolution 3D-CT bone models two weeks after surgery. Anterolateral rotatory translation was examined using a Slocum anterolateral rotatory instability test in open magnetic resonance imaging (MRI) 1.0-1.5 years after surgery, by measuring anterior tibial translation at the medial and lateral compartments on its sagittal images. Anterior-posterior stability was evaluated with a Kneelax3 arthrometer.RESULTSA total of 40 patients (80%) were finally followed up. Femoral tunnel positions were shallower (P < 0.01) and higher (P < 0.001), and tibial tunnel positions were more posterior (P < 0.05) in the TT group compared with the TP group. Anterolateral rotatory translations in reconstructed knees were significantly correlated with the shallow femoral tunnel positions (R = 0.42, P < 0.01), and the rotatory translations were greater in the TT group (3.2 ± 1.6 mm) than in the TP group (2.0 ± 1.8 mm) (P < 0.05). Side-to-side differences of Kneelax3 arthrometer were 1.5 ± 1.3 mm in the TT, and 1.7 ± 1.6 mm in the TP group (N.S.). Lysholm scores, KOOS subscales and re-injury rate showed no difference between the two groups.CONCLUSIONAnterolateral rotatory instability significantly correlated shallow femoral tunnel positions after ACL reconstruction using BTB autografts. Clinical outcomes, rotatory and anterior-posterior stability were overall satisfactory in both techniques, but the TT technique located femoral tunnels in shallower and higher positions, and tibial tunnels in more posterior positions than the TP technique, thus increased the anterolateral rotation. Anatomic ACL reconstruction with BTB autografts may restore knee function and stability.

The transportal technique shows better clinical results than the transtibial techniques for single-bundle anterior cruciate ligament reconstruction.

Although anatomical and independent drilling techniques, such as transportal (TP) technique, have become more popular in anterior cruciate ligament (ACL) reconstruction, the TP technique has not been shown to yield superior clinical or functional outcomes compared to the transtibial (TT) technique. The aim of the current meta-analysis was to compare clinical outcomes of the TP and TT techniques, as determined by patient-reported outcome scores and knee joint laxity tests. It was hypothesized that the TP and TT techniques of ACL reconstruction would yield similar patient-reported functional outcomes and similar results on knee joint laxity tests. Studies were included if they reported at least one of the following clinical outcomes: IKDC score, IKDC examination, Lysholm knee score, and Tegner activity score. Knee stability was evaluated by single or multiple parameters of the following knee laxity examinations: the Lachman test, the pivot shift test, and side-to-side difference on the instrumented knee laxity test. Sixteen studies were finally included in this meta-analysis. The proportions of patients with normal grade on the IKDC examination [odds ratio (OR) 2.23; 95% confidence interval (CI) 1.41-3.53; P = 0.0006] and Lysholm score (mean difference 1.27; 95% CI 0.23-2.31; P = 0.02) after surgery were higher with the TP than with the TT technique, but there were no differences in IKDC and Tegner scores. The postoperative proportion of normal knee joint stability was significantly higher with the TP than the TT technique, on both Lachman (OR 2.29; 95% CI 1.35-3.92; P = 0.002) and pivot shift (OR 2.13; 95% CI 1.12-4.05; P = 0.02) tests. The pooled mean side-to-side difference was 0.73mm lower with the TP than the TT technique (95% CI -1.14 to -0.32mm; P = 0.0005). This meta-analysis showed that the clinical outcomes of ACL reconstruction were better with the TP than the TT technique, both on knee functional outcome scales and knee laxity tests. The findings thus suggest that the TP technique would be a better option for single-bundle ACL reconstruction compared to the TT technique. III.

No clinical differences between anteromedial portal and transtibial technique for femoral tunnel positioning in anterior cruciate ligament reconstruction: a prospective randomized, controlled trial.

The anteromedial (AMP) portal technique was introduced to position the femoral tunnel in anterior cruciate ligament (ACL) reconstruction to more closely replicate the original ACL footprint compared to the transtibial (TT) approach. Few randomized trials have evaluated differences in these techniques with respect to clinical outcomes. The purpose of this study was to determine if there are any differences in clinical outcome between the AMP and TT approaches. This is a single-blinded, prospective, randomized controlled trial. Participants were randomized to undergo ACL reconstruction using the AMP or TT approach. The primary outcome measure was the ACL quality of life (ACL-QOL), and secondary outcomes were the IKDC knee assessment, side-to-side difference in anterior-posterior knee laxity (KT-1000) and tunnel orientation (X-ray findings) at preoperative, 3, 6, 12, and 24months postoperative. Statistical comparisons were performed using a series of t tests for independent groups with equal variance. Ninety-six participants were consented and randomized between 2007 and 2011 with eight excluded postrandomization. Mean (SD) preoperative ACL-QOL was 33 (13) for TT and 36 (17) for AMP and improved significantly (p<0.001) in both groups to 79 (18) and 78 (18) at 24months postoperative, respectively. The preoperative median IKDC grade for both groups was C and improved similarly in both groups at 24months (n.s.). There was no side-to-side difference in knee laxity based on KT-1000 measurements with a mean (SD) 1 (3) mm between affected and unaffected limbs in the TT group compared to 1 (3) mm for the AMP group. A significant difference was found in femoral tunnel orientation with the AMP group at 43° (7) and the TT group 58° (8) in the coronal plane (p<0.001). No differences in clinical outcome were found when comparing AMP to TT in primary ACL reconstruction using a STG graft. This prospective randomized controlled trial suggests surgeons can use either method without significantly compromising clinical outcome. I.

Transtibial Versus Anteromedial Portal ACL Reconstruction: Is a Hybrid Approach the Best?

Background:Improved biomechanical and clinical outcomes are seen when the femoral tunnels of the anterior cruciate ligament (ACL) are placed in the center of the femoral insertion. The transtibial (TT) technique has been shown to be less capable of this than an anteromedial (AM) portal approach but is more familiar to surgeons and less technically challenging. A hybrid transtibial (HTT) technique using medial portal guidance of a transtibial guide wire without knee hyperflexion may offer anatomic tunnel placement while maintaining the relative ease of a TT technique.Purpose:To evaluate the anatomic and biomechanical performance of the HTT technique compared with TT and AM approaches.Study Design:Controlled laboratory study.Methods:Thirty-six paired, fresh-frozen human knees were used. Twenty-four knees (12 pairs) underwent all 3 techniques (TT, AM, HTT) for femoral tunnel placement, with direct measurement of femoral insertional overlap and femoral tunnel length. The remaining 12 knees (6 pairs) underwent completed reconstructions to evaluate graft anisometry and tunnel orientation, with each technique performed in 4 specimens and tested using motion sensors with a quad-load induced model. Graft length changes and graft/femoral tunnel angle were measured at varying degrees of flexion.Results:Percentage overlap of the femoral insertion averaged 37.0% ± 28.6% for TT, 93.9% ± 5.6% for HTT, and 79.7% ± 7.7% for AM, with HTT significantly greater than both TT (P = .007) and AM (P = .001) approaches. Graft length change during knee flexion (anisometry) was 30.1% for HTT, 12.8% for AM, and 8.5% for TT. When compared with the TT approach, HTT constructs exhibited comparable graft–femoral tunnel angulation (TT, 150° ± 3° vs HTT, 142° ± 2.3°; P < .001) and length (TT, 42.6 ± 2.8 mm vs HTT, 38.5 ± 2.0 mm; P = .12), while AM portal tunnels were significantly shorter (31.6 ± 1.6 mm; P = .001) and more angulated (121° ± 6.5°; P < .001).Conclusion:The HTT technique avoids hyperflexion and maintains femoral tunnel orientation and length, similar to the TT technique, but simultaneously achieves anatomic graft positioning.Clinical Relevance:The HTT technique offers an anatomic alternative to an AM portal approach while maintaining the technical advantages of a traditional TT reconstruction.

Femoral Tunnel Drilling Method: Revision Risk After Anterior Cruciate Ligament Reconstruction

Objectives:The femoral tunnel in anterior cruciate ligament reconstruction (ACLR) can be created by the transtibial (TT) or tibial-independent (TI) methods. An anatomically located femoral tunnel can be more consistently achieved by TI methods, which include the medial portal (MP) and lateral (outside-in, retrodrill) techniques. Non-anatomic graft placement in ACLR may result in postoperative instability and meniscal or chondral pathology. An anatomically located graft may be subjected to higher postoperative physiologic forces than one placed non-anatomically. The purpose of this study was to examine isolated primary ACLR and determine the risk of aseptic revision based on femoral tunnel drilling method.Methods:A retrospective cohort study was conducted using an integrated U.S. healthcare system’s ACLR Registry to identify primary isolated unilateral cases from 2009 to 2014. Bilateral, double-bundle and multi-ligament reconstructions were excluded. Patients were divided into two groups based on femoral tunnel drilling method, TT or TI. Drilling method was evaluated as a risk factor for aseptic revision, with adjustment for age, sex, body mass index (BMI), race, and graft type using multivariable Cox proportional-hazards regression models.Results:19,022 primary ACLR patients were included, of whom 6,991 (36.8%) were younger than 22 years old, 11,772 (61.9%) were male, 7,632 (40.1%) had a BMI < 25 kg/m2, 8,894 (46.8%) were White, and 7,403 (38.9%) received an allograft. There were 12,336 (64.9%) ACLRs performed using TI techniques (MP n=10,149, lateral n=2,187) and 6,686 (35.1%) using the TT method. Usage of TI approaches increased from 34% of all ACLR in 2009 to 84% in 2014. The cumulative reoperation probability at 5-year follow-up was lower in the TI group, 7.5% (95% CI 6.6-8.4), compared to the TT group, 8.2% (95% CI 7.4-9.1). After adjusting for the covariates, the cumulative failure probability at 5-year follow-up was higher in the TI group, 6.3% (95% CI 5.6-7.2), compared to the TT group, 5.0% (95% CI 4.3-5.7). [Figure 1] After adjusting for the covariates, the TI group had a higher risk for aseptic revision than the TT group (HR=1.4. 95% CI=1.1-1.7).Conclusion:In the largest known study of its type examining femoral tunnel drilling method for primary ACLR, after adjusting for age, sex, BMI, race and graft type, TI techniques were found to have a 1.4 times higher risk of revision than the TT method. Surgeons should be aware that ACLR grafts placed more anatomically by TI methods have a higher risk of revision, possibly due to higher postoperative physiologic graft forces experienced.

In\u2013out versus out\u2013in technique for ACL reconstruction: a prospective clinical and radiological comparison

BackgroundSeveral studies have recently shown better restoration of normal knee kinematics and improvement of rotator knee stability after reconstruction with higher femoral tunnel obliquity. The aim of this study is to evaluate tunnel obliquity, length, and posterior wall blowout in single-bundle anterior cruciate ligament (ACL) reconstruction, comparing the transtibial (TT) technique and the out–in (OI) technique.Materials and methodsForty consecutive patients operated on for ACL reconstruction with hamstrings were randomly divided into two groups: group A underwent a TT technique, while group B underwent an OI technique. At mean follow-up of 10 months, clinical results and obliquity, length, and posterior wall blowout of femoral tunnels in sagittal and coronal planes using computed tomography (CT) scan were assessed.ResultsIn sagittal plane, femoral tunnel obliquity was 38.6 ± 10.2° in group A and 36.6 ± 11.8° in group B (p = 0.63). In coronal plane, femoral tunnel obliquity was 57.8 ± 5.8° in group A and 35.8 ± 8.2° in group B (p = 0.009). Mean tunnel length was 40.3 ± 1.2 mm in group A and 32.9 ± 2.3 mm in group B (p = 0.01). No cases of posterior wall compromise were observed in any patient of either group. Clinical results were not significantly different between the two groups.ConclusionsThe OI technique provides greater obliquity of the femoral tunnel in coronal plane, along with satisfactory length of the tunnel and lack of posterior wall compromise.Level of evidenceII, prospective study.