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

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

Background

A novel hybrid transtibial (HTT) approach to femoral tunnel drilling in anterior cruciate ligament reconstruction (ACLR) has been developed that circumvents the need for knee hyperflexion and orients the graft in the most anatomic position without sacrificing the tunnel length or aperture.

Hypothesis

Patients who underwent ACLR utilizing the HTT technique would achieve excellent patient-reported outcome scores and experience low rates of graft failure and reoperations.

Study Design

Case series; Level of evidence, 4.

Methods

Patients who underwent primary ACLR at a single institution between 2005 and 2020 were retrospectively reviewed. Patients treated with the HTT, anteromedial portal (AMP), and transtibial (TT) approaches were matched based on age, sex, and body mass index ±3 kg/m2. Demographic and surgical data as well as femoral tunnel angle measurements on anteroposterior and lateral radiographs were collected for the 3 groups. However, clinical outcomes were only reported for the HTT group because of concerns of graft heterogeneity.

Results

A total of 170 patients (median age, 26.5 years [interquartile range (IQR), 18.0-35.0 years]) who underwent ACLR using the HTT approach were included. The median coronal- and sagittal-plane femoral tunnel angles were 47° (IQR, 42°-53°) and 40° (IQR, 34°-46°), respectively. The sagittal-plane femoral tunnel angles in the HTT group were significantly more horizontal compared with those in the TT group (P < .0001), whereas the coronal-plane femoral tunnel angles in the HTT group were found to be significantly more vertical compared with those in the AMP group (P = .001) and more horizontal compared with those in the TT group (P < .0001). The graft failure and reoperation rates in the HTT group at a minimum 2-year follow-up were 1.8% (3/170) and 4.7% (8/170), respectively. The complication rate was 6.5% (11/170), with the most common complication being subjective stiffness in 7 patients. The median Lysholm score was 89.5 (IQR, 79.0-98.0); the median International Knee Documentation Committee score was 83.9 (IQR, 65.5-90.8); and the median Veterans RAND 12-Item Health Survey physical and mental component summary scores were 55.0 (IQR, 52.6-55.9) and 56.2 (IQR, 49.1-59.3), respectively.

Conclusion

ACLR using the HTT technique was associated with low graft retear and revision surgery rates and good patient-reported outcome scores at medium-term follow-up and demonstrated femoral tunnel obliquity on postoperative radiographs that correlated with optimal parameters previously reported in cadaveric and biomechanical studies.

Finite element graft stress for anteromedial portal, transtibial, and hybrid transtibial femoral drillings under anterior translation and medial rotation: an exploratory study

Stress concentration on the Anterior Cruciate Ligament Reconstruction (ACLr) for femoral drillings is crucial to understanding failures. Therefore, we described the graft stress for transtibial (TT), the anteromedial portal (AM), and hybrid transtibial (HTT) techniques during the anterior tibial translation and medial knee rotation in a finite element model. A healthy participant with a non-medical record of Anterior Cruciate Ligament rupture with regular sports practice underwent finite element analysis. We modeled TT, HTT, AM drillings, and the ACLr as hyperelastic isotropic material. The maximum Von Mises principal stresses and distributions were obtained from anterior tibial translation and medial rotation. During the anterior tibia translation, the HTT, TT, and AM drilling were 31.5 MPa, 34.6 Mpa, and 35.0 MPa, respectively. During the medial knee rotation, the AM, TT, and HTT drilling were 17.3 MPa, 20.3 Mpa, and 21.6 MPa, respectively. The stress was concentrated at the lateral aspect of ACLr,near the femoral tunnel for all techniques independent of the knee movement. Meanwhile, the AM tunnel concentrates the stress at the medial aspect of the ACLr body under medial rotation. The HTT better constrains the anterior tibia translation than AM and TT drillings, while AM does for medial knee rotation.

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

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

A Novel Predictor of the Length and Size of ACL Grafts in Chinese Han Adults for ACL Reconstruction: An MRI Study

OBJECTIVE

Currently, there is no simple and valid method to predict the length and size of the native anterior cruciate ligament (ACL) in each adult patient who will undergo ACL reconstruction. This study aimed to develop an imaging prediction method that can predict the length and size of ACL grafts using the intact posterior cruciate ligament (PCL), in order to enhance the graft preparation individualized sizing.

METHODS

Three hundred and nineteen patients aged 18 years or older who underwent magnetic resonance imaging (MRI) of the knee at an orthopaedic clinic between September 9, 2021, and February 5, 2023, were included. The length, sagittal diameter, and coronal diameter of the ACL and PCL were measured in all patients, and F-test were performed to explore linear relationship between ligament measurements.

RESULTS

Equations were established to predict a variable of the native ACL for the corresponding variable of the intact PCL (i.e., sagittal diameter of the ACL = 4.32 + 1.08 × sagittal diameter of the PCL, and coronal diameter of the ACL = 2.45 + 0.59 × coronal diameter of the PCL, length of the male ACL = 10.92 + 0.64 × length of the male PCL, length of the female ACL = 11.76 + 0.58 × length of the female PCL) (R2  = 0.532; R2  = 0.417; R2  = 0.488; R2  = 0.509; respectively).

CONCLUSIONS

The length and size of the intact PCL in cases without PCL buckling are predictors of the length and size of the native ACL in adults, respectively. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in the future.

The Hybrid Transtibial Technique for Femoral Tunnel Drilling in Anterior Cruciate Ligament Reconstruction: A Finite Element Analysis Model of Graft Bending Angles and Peak Graft Stresses in Comparison With Transtibial and Anteromedial Portal Techniques

PURPOSE

The purpose of this finite element analysis was to compare femoral tunnel length; anterior cruciate ligament reconstruction graft bending angle; and peak graft stress, contact force, and contact area created by the transtibial, anteromedial portal (AMP), and hybrid transtibial techniques.

METHODS

Finite element analysis modeling was used to examine anterior cruciate ligament reconstruction models based on transtibial, AMP, and hybrid transtibial femoral tunnel drilling techniques. An evaluation of femoral tunnel length, graft bending angle, peak graft stress, contact force, and contact area was done in comparison of these techniques.

RESULTS

The femoral tunnel created with the hybrid transtibial technique was 45.3 mm, which was 13.3% longer than that achieved with the AMP technique but 15.2% shorter than that with the transtibial technique. The femoral graft bending angle with the hybrid transtibial technique (105°) was less acute than that with the AMP technique (102°), but more acute than that with the transtibial technique (109°). At 11° knee flexion, the hybrid transtibial technique had 22% less femoral contact force, 21% less tibial contact force, 21% less graft tension than the AMP technique. Yet, the hybrid transtibial technique had 41% greater femoral contact force, 39% greater tibial contact force, 33% greater graft tension, and 6% greater graft von Mises stress than the transtibial technique. A similar trend was found for the anterior knee drawer test. At both 6-mm anterior tibial displacement and 11° knee flexion, the hybrid transtibial and AMP techniques had at least 51% more femoral contact area than the transtibial technique.

CONCLUSION

This finite element analysis highlights that the hybrid transtibial technique is a true hybrid between the AMP and transtibial techniques for femoral tunnel drilling regarding femoral tunnel length, graft bending angle, and peak graft stress.

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.

Transtibial versus independent femoral tunnel drilling techniques for anterior cruciate ligament reconstruction: evaluation of femoral aperture positioning

Background

Femoral tunnel can be drilled through tibial tunnel (TT), or independent of it (TI) by out-in (OI) technique or by anteromedial (AM) technique. No consensus has been reached on which technique achieves more proper femoral aperture position because there have been evolving concepts in the ideal place for femoral aperture placement. This meta-analysis was performed to analyze the current literature comparing femoral aperture placement by TI versus TT techniques in ACL reconstruction.

Methods

We performed a comprehensive systematic review and meta-analysis of English-language literature in PubMed, Cochrane, and Web of Science databases for articles comparing femoral aperture placement by TI versus TT techniques with aperture position assessed by direct measurement or by postoperative imaging, PXR and/or CT and/or MRI.

Results

We included 55 articles with study population of 2401 knees of whom 1252 underwent TI and 1149 underwent TT techniques. The relevant baseline characteristics, whenever compared, were comparable between both groups. There was nonsignificant difference between TI and TT techniques in the distance from aperture center to footprint center and both techniques were unable to accurately recreate the anatomic footprint position. TI technique significantly placed aperture at more posterior position than TT technique. TI technique significantly lowered position of placed aperture perpendicular to Blumensaat’s line (BL) than TT technique, and modifications to TT technique had significant effect on this intervention effect. Regarding sagittal plane aperture placement along both AP anatomical axis and BL, there was nonsignificant difference between both techniques.

Conclusion

Modifications to TT technique could overcome limitations in aperture placement perpendicular to BL. The more anterior placement of femoral aperture by TT technique might be considered, to some extent, a proper position according to recent concept of functional anatomical ACL reconstruction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03040-5.

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.

Achilles Tendon Allograft Preparation Technique for Anterior Cruciate Ligament Reconstruction: A Technical Note

Several factors associated with graft preparation for the surgery of the anterior cruciate ligament (ACL) like the wrong thawed, prophylaxis, bone cuts, excessive bone removal as well as positioning problems like a tunnels-graft mismatch, insufficient harvesting of the donor's tendon, size graft limitations (length and diameter), uncontrolled rotation of graft in their longitudinal axis, over or under tensioned graft, fixation mistakes, bone defects, secondary arthrofibrosis or morbidity of the donor site, and others factors importantly affect the outcomes of the ACL surgery. In this sense, the Achilles tendon Allograft is an advantageous technique where many of the previous limitation factors described can be controlled during an appropriate preparation. However, to obtain the maximum potentialities of the graft a detailed knowledge of the preparation is required. Hence, we aimed to describe how to prepare the Achilles tendon Allograft to control the graft's length and diameter, bone removal, and fixation requirements.

Comparison of Clinical Outcomes between Anteromedial and Transtibial Techniques of Single-Bundle Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

This study compared clinical outcomes obtained after single-bundle anterior cruciate ligament (ACL) reconstruction using the anteromedial (AM) and transtibial (TT) techniques, which comprise the conventional transtibial (cTT) and modified transtibial (mTT) techniques. This study included clinical randomized controlled trials and prospective and retrospective controlled trials with AM and TT techniques from the PubMed and Embase databases and the Cochrane Library. All databases were searched from January 2010 to July 2020. Two independent evaluators verified the quality of the included studies using the Cochrane Collaboration's risk of bias tool and the Newcastle-Ottawa Scale (NOS). Outcome measures analysed included the Lachman test, pivot-shift test, side-to-side difference (SSD), Lysholm score, Tegner activity scale, International Knee Documentation Committee (IKDC) grade and score. Ten randomized controlled trials (RCTs) and 16 prospective and retrospective controlled trials were included with a total of 2202 patients. There were 1180 patients and 1022 patients in the AM and TT groups, respectively. Compared to the cTT group, superior postoperative results were observed in the AM group based on the negative rate of the Lachman test and the pivot-shift test, IKDC grade and score, Lysholm score, Tegner activity scale and SSD (p < 0.05). However, there was no significant difference between the AM and mTT groups (p > 0.05). Compared to the conventional TT technique, the AM technique exhibited superior clinical outcomes. Nevertheless, the modified TT and AM techniques had comparable results. With neither of the techniques (mTT or AM) producing significantly superior outcomes, surgeons can choose either of them depending on their preferences.

Allograft Augmentation of Hamstring Autograft in Anterior Cruciate Ligament Reconstruction Results in Equivalent Outcomes to Autograft Alone

PURPOSE

To examine allograft augmentation of undersized hamstring (HS) autograft tendons at the time of anterior cruciate ligament (ACL) reconstruction, compared with un-augmented autograft HS ACL reconstruction.

METHODS

Patients who underwent ACL reconstruction at our institution between 2005 and 2015 were reviewed. Inclusion criteria included patients who underwent (1) primary ACL reconstruction, (2) use of a hybrid HS autograft with allograft augmentation, and (3) had a minimum 2-year postoperative follow-up. Patients with revision ACL, multiligamentous injuries, all-epiphyseal fixation techniques, or additional procedures beyond chondroplasty or meniscal repair/debridement were excluded. Data collected included demographics, graft size, concomitant procedures, revision operation, revision ACL reconstruction, and patient-reported outcomes.

RESULTS

In total, 59 patients met criteria for inclusion into the hybrid group, and 80 patients were eligible for inclusion into the control group. The average age of the cohort was 22.9 (interquartile range Q1:17, Q3: 38.3), and 51.8% of the patients were female. Seven patients (11.9%) in the hybrid ACL group underwent revision ACL surgery versus 15 (18.8%) in the control group (P = .27). There was no difference in patient-reported outcomes between groups.

CONCLUSIONS

Augmenting an HS ACL autograft that is 8 mm or less with allograft tissue to increase the overall size of the ACL graft shows no difference in overall reoperation or revision of ACL failure. The hybrid autograft/allograft ACL reconstruction patients showed no clinically important difference between groups in patient-reported outcome measures.

LEVEL OF EVIDENCE

Level III, case-control comparative analysis.

ACL Reconstruction Graft Angle and Outcomes: Transtibial vs Anteromedial Reconstruction

BACKGROUND

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.

QUESTIONS/PURPOSES

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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 2 years 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.

A Hybrid Transtibial Technique Combines the Advantages of Anteromedial Portal and Transtibial Approaches: A Prospective Randomized Controlled Trial

BACKGROUND

The anteromedial (AM) portal and transtibial (TT) approaches are 2 common anterior cruciate ligament (ACL) femoral tunnel drilling techniques, each with unique benefits and disadvantages. A hybrid TT (HTT) technique using medial portal guidance of a flexible TT guide wire has recently been described that may combine the strengths of both the AM portal and the TT approaches.

HYPOTHESIS

The HTT technique will achieve anatomic femoral tunnel apertures similar to the AM portal technique, with improved femoral tunnel length and orientation.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 30 consecutive patients with primary ACL tears were randomized to undergo the TT, AM portal, or HTT technique for femoral tunnel positioning at the time of reconstruction. All patients underwent 3-dimensional computed tomography of the operative knee at 6 weeks postoperatively. Femoral and tibial tunnel aperture positions and tunnel lengths, as well as graft bending angles in the sagittal and coronal planes, were measured.

RESULTS

Tibial tunnel lengths and aperture positions were identical between the 3 groups. The AM portal and HTT techniques achieved identical femoral aperture positions in regard to both height (P = .629) and depth (P = .582). By contrast, compared with the AM portal and HTT techniques, femoral apertures created with the TT technique were significantly higher (P < .001 and P < .001, respectively) and shallower (P = .014 and P = .022, respectively) in the notch. The mean femoral tunnel length varied significantly between the groups, measuring 35.2, 41.6, and 54.1 mm for the AM portal, HTT, and TT groups, respectively (P < .001). Last, there was no difference between the mean coronal (P = .190) and sagittal (P = .358) graft bending angles between the TT and HTT groups. By contrast, compared with the TT and HTT techniques, femoral tunnels created with the AM portal technique were significantly more angulated in the coronal plane (17.7° [P < .001] and 12.5° [P = .006], respectively) and sagittal plane (13.5° [P < .001] and 10.5° [P = .013], respectively).

CONCLUSION

This prospective randomized controlled trial found that the HTT technique achieved femoral aperture positions equally as anatomic as the AM portal technique but produced longer, less angulated femoral tunnels, which may help reduce graft strain and mismatch. As such, this hybrid approach may represent a beneficial combination of both the TT and the AM portal techniques.

REGISTRATION

NCT02795247 (ClinicalTrials.gov identifier).

Transphyseal Anterior Cruciate Ligament Reconstruction Using Hybrid Transtibial Femoral Drilling and a Quadriceps Tendon Autograft

Significant controversy exists regarding the optimal surgical technique for anterior cruciate ligament (ACL) reconstruction in adolescents with 1 to 3 years of skeletal growth remaining. Graft choice and physeal injury remain primary concerns given significantly elevated rates of failure of hamstring autograft reconstructions in this population, as well as risks of leg-length discrepancy and growth axis deviation. Traditional (more vertical) transtibial drilling of the femoral tunnel can reduce risks of physeal injury but has been shown to have less accuracy restoring the native femoral ACL footprint and associated incomplete knee stabilization. On the other hand, anteromedial and outside-in drilling yields improvements in the tunnel location and biomechanics but at the cost of a more oblique trajectory and greater risk of physeal injury. A hybrid transtibial pin technique using a Pathfinder guide facilitates femoral drilling with the "best of both worlds," allowing for reproduction of the native ACL footprint and a more physeal-respecting femoral tunnel. When combined with an all-soft tissue quadriceps tendon autograft and suspensory fixation, the hybrid transtibial method yields a reliable, safe, and robust construct with promising results for the young athlete. We describe our preferred graft harvest, tunnel drilling, and fixation techniques to minimize physeal risks and optimize outcomes.

Techniques for Femoral Socket Creation in ACL Reconstruction

Anterior cruciate ligament (ACL) injury is common and affects a wide variety of individuals. An ACL reconstruction is the treatment of choice for patients with subjective and objective symptoms of instability and is of particular importance to cutting or pivoting athletes. With many variables involved in ACL reconstruction, femoral tunnel placement has been found to affect clinical outcomes with nonanatomic placement being identified as the most common technical error. Traditionally the femoral tunnel was created through the tibial tunnel or transtibial with the use of a guide and a rigid reaming system. Because of proximal, nonanatomic tunnel placement using the transtibial technique, the use of the anteromedial portal and outside-in drilling techniques has allowed placement of the tunnel over the femoral footprint. In this paper, we discuss the difference between the 3 techniques and the advantages and disadvantages of each. The authors then explore the clinical differences and outcomes in techniques by reviewing the relevant literature.

Comparison of femoral tunnel length and obliquity of anatomic versus nonanatomic anterior cruciate ligament reconstruction: A meta-analysis

Purpose

Theoretical considerations suggest that femoral tunnel length might cause graft mismatch, and femoral tunnel obliquity could be related to the longevity of graft in anterior cruciate ligament (ACL) reconstruction. However, controversy still exists regarding these issues in the context of the comparison of anatomic and nonanatomic ACL reconstructions. The purpose of this meta-analysis was to compare the length and obliquity of the femoral tunnel created by drilling through either anatomic or nonanatomic ACL reconstructions.

Materials and method

In this meta-analysis, we reviewed studies that compared femoral tunnel length and femoral tunnel obliquity in the coronal plane with the use of anatomic or nonanatomic ACL reconstruction. The major databases were reviewed for appropriate studies from the earliest available date of indexing through December 31, 2018. No restrictions were placed on the language of publication.

Results

Twenty-seven studies met the criteria for inclusion in this meta-analysis. The femur tunnel length of anatomic ACL reconstruction was significantly shorter compared with that of nonanatomic ACL reconstruction by 8.66 mm (95% CI: 7.10–10.22 mm; P<0.001), while the femur tunnel obliquity in the coronal plane of anatomic ACL reconstruction was significantly more oblique versus that of nonanatomic ACL reconstruction by 15.29° (95% CI: 8.07°–22.52°; P<0.001). Similar results in terms of femoral tunnel length were found for the subgroup with cadaveric (7.15 mm; 95% CI: 2.69–11.61 mm; P = 0.002) and noncadaveric (8.96 mm; 95% CI: 7.24–10.69 mm; P<0.001) studies, whereas different results in terms of femoral tunnel obliquity were noted for the subgroup with cadaveric (10.62°; 95% CI: −6.12° to 27.37°; P = 0.21) and noncadaveric (15.86°; 95% CI: 8.11°–23.60°; P<0.001) studies.

Conclusion

Anatomic ACL reconstruction resulted in the femoral tunnel length and femoral tunnel obliquity in the coronal plane being shorter and more oblique, respectively, as compared with nonanatomic ACL reconstruction.

Level of evidence

Therapeutic study, Level III.

Positioning Technique of the Fixed Knee in Hyperflexion for the Transportal Femoral Tunnel During Reconstruction of the Anterior Cruciate Ligament

During reconstruction surgery of the anterior cruciate ligament, the evolution of the femoral tunnel from the transtibial to the transportal path provides greater accuracy in reaching the desired anatomic point. However, there are also some new challenges, such as correct execution, reproducibility, and minimizing the risk of iatrogenic injury from its use. In an effort to overcome these challenges, we have proposed the use of a positioner, which was developed by our group and allows the leg to stay in the desired position, without variations in the operation or aid from a medical assistant. This manuscript presents our femoral tunnel preparation technique and its application in clinical practice.

Outcome of posterior wall blowout in anterior cruciate ligament (ACL) reconstruction via anteromedial portal approach: A retrospective research in 20 patients with 6 years follow-up

PURPOSE

To evaluate the clinical outcome in patients who received anterior cruciate ligament (ACL) reconstruction via anteromedial portal with or without posterior wall blowout.

METHODS

Twenty patients with ruptured ACL, who have received ACL reconstruction via anteromedial portal between Apr 2012 and Oct 2013 were enrolled. According to the conditions of posterior wall, the patients were divided into 2 groups: posterior wall blowout group (10 patients) and posterior wall intact group (10 patients). The median follow up time were 63 (range 19-75) months and 60.5 (range 25-64) months in the 2 groups respectively. The clinical outcome was evaluated by knee joint physical examination, magnetic resonance imaging (MRI), the International Knee Documentation Committee (IKDC) 2000 subjective score, Lysholm score, Tenger score, difference of thigh circumference, KT-2000 and Biodex isokinetic dynamometer system.

RESULTS

No significant differences were found in terms of the IKDC score, Lysholm score, Tegner score, Lachman test positive rate or Pivot Shift test positive rate between the two groups. In KT-2000 and Biodex isokinetic dynamometer tests, the difference of muscle strength between affected knees and unaffected knees in posterior wall blowout group was not significant less than that of posterior wall intact group (p > 0.05). In addition, there is no statistical difference between the two groups in signal/noise quotient (SNQ) of the graft (p > 0.05) in post operative MRI.

CONCLUSION

Blowout of posterior wall in ACL reconstruction via anteromedial portal does not affect the clinical outcome as long as reliable fixation is taken intraoperatively.

Modified transtibial versus anteromedial portal techniques for anterior cruciate ligament reconstruction, a comparative study

PURPOSE

This study compared the accessory anteromedial portal (AAMP) and the modified transtibial technique (MTTT)" for single-bundle anterior cruciate ligament (ACL) reconstruction.

PATIENTS AND METHODS

Sixty active adult patients with ACL tear were randomly assigned into two equal groups who were treated surgically. One group was operated on using AAMP and the other group through MTTT. Both the groups had the same postoperative course and were followed for 1 year after surgery. The follow-up included Lysholm and International Knee Documentation Committee (IKDC) subjective knee evaluation forms, IKDC objective knee examination form, and radiological evaluation. Results were evaluated and compared with each other.

RESULTS

There was no significant difference in subjective effects or clinical examination between the two groups. Regarding radiological angles, the AAMP had more oblique graft orientation in the coronal plane than the MTTT, but both were found to be more slanted than native ACL. Also, the MTTT had succeeded to place the graft and tunnel more obliquity than the traditional non-anatomic TTT and better than the anatomic ranges despite having the graft inclination of the AAMP higher than the MTTT. The complaints from the patients and subjective scoring were found to be positively related to graft stability. Patients with healthier preoperative subjective state had a smoother postoperative period and better outcome.

CONCLUSION

This study offers simple modifications to the transtibial technique to allow near anatomic ACL reconstruction with similar results comparable to the AAMP and with fewer complications.