Transtibial Drilling Techniques Research Articles

Risk factors for reoperation for arthrofibrosis following primary anterior cruciate ligament reconstruction.

The purpose of this study is to identify the rate and risk factors for a reoperation for arthrofibrosis following primary anterior cruciate ligament (ACL) reconstruction. Prospective data recorded in the New Zealand ACL Registry were cross-referenced with data from the Accident Compensation Corporation (ACC). Primary ACL reconstructions performed between April 2014 and May 2021 were analysed. The ACC database was used to identify patients who underwent a reoperation for a diagnosis of arthrofibrosis. Multivariable survival analysis was performed to compute adjusted hazard ratios (aHR) and 95% confidence intervals. A total of 12,296 primary ACL reconstructions were analysed, of which 230 underwent a reoperation for arthrofibrosis (1.9%) at a mean follow-up of 3.6 years. A higher risk of arthrofibrosis was observed in females (aHR = 1.76, p = 0.001), patients with a history of previous knee surgery (aHR = 1.82, p = 0.04) and when a transtibial drilling technique was used (aHR = 1.53, p = 0.03). ACL reconstruction >6 months after injury had the lowest rate of arthrofibrosis (1.3%, aHR = 0.45, p = 0.01). There was no difference in risk between early surgery within 6 weeks versus delayed surgery between 6 weeks and 6 months after injury (2.9% versus 2.1%, aHR = 0.78, not significant). Female sex, previous knee surgery and a transtibial drilling technique increased the risk of reoperation for arthrofibrosis. Early surgery within 6 weeks of injury was not associated with an increased risk when compared with surgery between 6 weeks and 6 months after injury. Level III.

Evaluating femoral graft placement using three-dimensional magnetic resonance imaging in the reconstruction of the anterior cruciate ligament via independent or transtibial drilling techniques: a retrospective cohort study.

Anterior cruciate ligament (ACL) reconstruction is a common surgical procedure, yet failure still largely occurs due to nonanatomically positioned grafts. The purpose of this study was to retrospectively evaluate patients with torn ACLs before and after reconstruction via 3D MRI and thereby assess the accuracy of graft position on the femoral condyle. Forty-one patients with unilateral ACL tears were recruited. Each patient underwent 3D MRI of both knees before and after surgery. The location of the reconstructed femoral footprint relative to the patient's native footprint was compared. Native ACL anatomical location of the native ACL had a significant impact on graft position. Native ACLs that were previously more anterior yielded grafts that were more posterior (3.70 ± 1.22mm, P = 0.00018), and native ACL that were previously more proximal yielded grafts that were more distal (3.25 ± 1.09mm, P = 0.0042). Surgeons using an independent drilling method positioned 76.2% posteriorly relative to the native location, with a mean 0.1 ± 2.8mm proximal (P = 0.8362) and 1.8 ± 3.0mm posterior (P = 0.0165). Surgeons using a transtibial method positioned 75% proximal relative to the native location, with a mean 2.2 ± 3.0mm proximal (P = 0.0042) and 0.2 ± 2.6mm posterior (P = 0.8007). These two techniques showed a significant difference in magnitude in the distal-proximal axis (P = 0.0332). The femoral footprint position differed between the native and reconstructed ACLs, suggesting that ACL reconstructions are not accurate. Rather, they are converging to a normative reference point that is neither anatomical nor isometric.

Meniscal repair failure following concurrent primary anterior cruciate ligament reconstruction: results from the New Zealand ACL Registry

PurposeThis study aimed to identify the risk factors for meniscal repair failure following concurrent primary anterior cruciate ligament (ACL) reconstruction.MethodsProspective data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation were reviewed. Meniscal repairs performed during concurrent primary ACL reconstruction were included. Repair failure was defined as a subsequent reoperation involving meniscectomy of the repaired meniscus. Multivariate survival analysis was performed to identify the risk factors for failure.ResultsA total of 3,024 meniscal repairs were analysed with an overall failure rate of 6.6% (n = 201) at a mean follow-up of 2.9 years (SD 1.5). The risk of medial meniscal repair failure was higher with hamstring tendon autografts (adjusted HR [aHR] = 2.20, 95% CI 1.36–3.56, p = 0.001), patients aged 21–30 years (aHR = 1.60, 95% CI 1.30–2.48, p = 0.037) and in patients with cartilage injury in the medial compartment (aHR = 1.75, 95% CI 1.23–2.48, p = 0.002). The risk of lateral meniscal repair failure was higher in patients aged ≤ 20 years (aHR = 2.79, 95% CI 1.17–6.67, p = 0.021), when the procedure was performed by a low case volume surgeon (aHR = 1.84, 95% CI 1.08–3.13, p = 0.026) and when a transtibial technique was used to drill the femoral graft tunnel (aHR = 2.30, 95% CI 1.03–5.15, p = 0.042).ConclusionThe use of a hamstring tendon autograft, younger age and the presence of medial compartment cartilage injury are risk factors for medial meniscal repair failure, whereas younger age, low surgeon volume and a transtibial drilling technique are risk factors for lateral meniscal repair failure.Level of evidenceLevel II.

Anteromedial Portal versus Transtibial Drilling Techniques for Femoral Tunnel Placement in Arthroscopic Anterior Cruciate Ligament Reconstruction: Radiographic Evaluation and Functional Outcomes at 2 Years Follow-Up.

The aim of this study was to compare the functional and radiographic outcomes of arthroscopic single-bundle anterior cruciate ligament reconstruction (ACLR) using either the anteromedial (AM) portal technique or transtibial (TT) technique. We identified 404 patients who underwent arthroscopic ACLR by a single surgeon between January 2006 and December 2016 at our institution. The TT portal was utilized in femoral tunnel drilling in 202 patients (TT group) while the AM portal was used in 202 patients (AM group). The mean postoperative follow-up duration was 26 months (range: 24-33 months). Postoperative radiographic femoral and tibial tunnel positions were assessed by two independent observers. Functional outcomes were evaluated with Tegner, Lysholm, and Knee Injury and Osteoarthritis Outcome score (KOOS) scores. On the anteroposterior plain radiographs, the mean femoral tunnel position relative to the lateral femoral condyle was 46.8% for the AM group versus 48.6% in the TT group, respectively (p=0.003). The mean graft inclination angle was 31.9° and 22° in the AM and TT groups, respectively (p<0.0001). On the lateral radiographs, the mean femoral tunnel placement across Blumensaat's line in relation to the anterior femoral cortex was 84% in the AM group while it was 78% in the TT group (p<0.0001). At 2 years postoperatively, there were no significant differences in the mean Tegner, Lysholm, and KOOS scores between the two patient groups. The graft failure rate at 2 years follow-up was 4.5% (n=9) in the AM group while it was 2.5% (n=5) in the TT group (p=0.2). Femoral tunnel placement was more anatomical with the AM portal technique compared with the TT technique. However, there was no significant difference in postoperative functional outcomes between the two patient groups. The AM portal technique appears to have a higher graft failure rate. This might be attributed to increased graft loading in an anatomical position.

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.

Does Bone Plug and Graft Orientation (Inferior Versus Posterior) Alter Native Femoral Footprint Coverage in Bone Patellar Tendon Bone Anterior Cruciate Ligament Reconstruction?

The purpose of this study was to compare the percentage of native femoral anterior cruciate ligament (ACL) footprint covered by the 2 most clinically relevant bone plug/graft orientations used with interference screw fixation in ACL reconstruction. A secondary purpose was to assess whether a transtibial or tibia-independent drilling technique would affect this outcome. Five matched pairs of cadaver knees were used. Each matched pair had 1 knee assigned to a 10-mm femoral socket prepared via a transtibial (TT) drilling technique and the other via an anteromedial (AM) drilling technique. The bone plug of each graft was press-fitted into the femoral socket with the graft collagen in 2 distinct clinically relevant orientations (collagen inferior or posterior). The digitized graft collagen cross-sectional area(CSA) in each orientation was overlaid onto the native femoral ACL footprint CSA to generate a percentage of native ACL footprint covered by graft collagen. The average native ACL femoral footprint CSA was 110.5 ± 9.1 mm2, with no difference between knees assigned to TT or AM drilling (112.6 ± 2.7 vs 108.4 ± 13.0 mm2, P=.49). The average femoral socket CSA was 95.4 ± 8.7 mm2, with no difference between TT and AM tunnels (95.5 ± 9.9 vs 95.3 ± 8.4 mm2, P= .96). There was no difference between the percentage of native footprint covered between TT and AM sockets (76.8% ± 7.8% vs 82.2% ± 13.7%, P= .47). Irrespective of drilling technique, there was significantly greater native ACL footprint covered by graft collagen when the bone plug was oriented with graft collagen inferior rather than posterior (75.6% ± 6.3% vs 65.4% ± 11.4%, P= .02). Orienting the femoral bone plug such that the graft collagen is inferior rather than posterior significantly increases native ACL femoral footprint coverage in bone-patellar tendon-bone ACL reconstruction. This effect is consistent across AM and TT drilling techniques. Surgeons attempting to restore an anatomic ACL footprint should consider bone plug-graft orientation when performing ACL reconstruction. Controlled laboratory study.

Update on Failure Analysis of Implants in ACL Surgery: Technical Failure or Fate?

Reasons for failure of anterior cruciate ligament (ACL) reconstructions are manifold and require a multifactorial explanatory approach. In addition to technical failures, many modifiable and non-modifiable risk factors for a new ACL injury have to be considered. Technical failures primarily include non-anatomical tibial and femoral tunnel position. In comparison to the transtibial drilling technique, the tibial tunnel-independent technique results in a more anatomical position of the femoral tunnel and should therefore be preferred. One can differentiate between non-modifiable and modifiable risk factors. At the same time, the combination of more than one risk factor increases the risk of injury significantly. Non-modifiable risk factors include genetic predisposition, female sex, young age and ligament hyperlaxity. Young age at the time of the first injury is the most important risk factor for graft failure. Modifiable risk factors include high body mass index (BMI), deficits in jump landing mechanics, a steep posterior tibial slope and narrow intercondylar notch width. Neuromuscular training or additional surgical procedures modify these risk factors and reduce the probability of further injuries. A high tibial osteotomy (HTO) is the surgical procedure of choice for a reduction in the posterior tibial slope and anterior tibial translation. In case of a tibial slope over 12°, this procedure should be considered. In revision anterior cruciate ligament reconstructions with remaining anterolateral rotatory instability, additional lateral extraarticular tenodesis should be taken into account. This is also recommended for patients participating in pivoting sports, having concomitant hyperlaxity or additional injury of peripheral structures with insufficiency of the ACL. In addition, the surface of the pitch can be modified and thus influence the risk of an ACL injury. In summary, a substantiated failure analysis is required to initiate specific and individualised therapy - not only in the case of ACL rerupture. These factors should already be considered in risk assessment during patient information.

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.

MRI signs of anterior cruciate ligament graft restructuring in bone canal

One of the reason for succeed anterior cruciate ligament reconstruction is the process of graft remodeling on the border «tendon-bone» in the bone canal. This factor can influence on the mechanical stability of the knee joint after anterior cru­ciate ligament reconstruction and can determine the rehabilitation exercises.Objective: to work out MRI criteria of graft reconstruction in bone canals.Methods: we included 90 patients, who were divided into two groups: the 1st o ne ( 47) w e used the technique «all-inside», in the 2nd group (43) — cross transtibial drilling technique. In 8 patients MRI was made.Results: we suggested the next criteria for the assessment of graft reconstruction in femoral and tibia bone canals: 1) signs of reconstruction on the border «tendon-bone»; 2) synovial fluid in the bone canals; 3) femoral and tibia bone marrow edema. Number of patients with the 1st stage (full graft reconstruction) without synovial fluid in bone canal increased in follow up period 3 to 9 months. Number of patients without bone marrow edema increased in follow up 3 to 12 months (35,6; 54,4; 74,5 and 84,5 %). It was shown in 6 months that in the 1st group there was a prevalence of patients (60 %) with the 1st stage of reconstruc­tion compare with the 2nd group (42,2 %). As for the presence of synovial fluid in bone canal we observed a reliable difference in 3 months — 75,5 % in the 1st group compare with 78,9 % — in the 2nd.Conclusions: the dynamic of the graft reconstruction gets on the top till 9 months after surgery and after remains unchanged. The technique «all-inside» contributes faster and more qualitative graft reconstruction due to fewer trauma to the proxi­mal part of the tibia and absence of screws in the tibia canal.

ACL Roof Impingement Revisited: Does the Independent Femoral Drilling Technique Avoid Roof Impingement With Anteriorly Placed Tibial Tunnels?

Background:Anatomic femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is now well accepted. The ideal location for the tibial tunnel has not been studied extensively, although some biomechanical and clinical studies suggest that placement of the tibial tunnel in the anterior part of the ACL tibial attachment site may be desirable. However, the concern for intercondylar roof impingement has tempered enthusiasm for anterior tibial tunnel placement.Purpose:To compare the potential for intercondylar roof impingement of ACL grafts with anteriorly positioned tibial tunnels after either transtibial (TT) or independent femoral (IF) tunnel drilling.Study Design:Controlled laboratory study.Methods:Twelve fresh-frozen cadaver knees were randomized to either a TT or IF drilling technique. Tibial guide pins were drilled in the anterior third of the native ACL tibial attachment site after debridement. All efforts were made to drill the femoral tunnel anatomically in the center of the attachment site, and the surrogate ACL graft was visualized using 3-dimensional computed tomography. Reformatting was used to evaluate for roof impingement. Tunnel dimensions, knee flexion angles, and intra-articular sagittal graft angles were also measured. The Impingement Review Index (IRI) was used to evaluate for graft impingement.Results:Two grafts (2/6, 33.3%) in the TT group impinged upon the intercondylar roof and demonstrated angular deformity (IRI type 1). No grafts in the IF group impinged, although 2 of 6 (66.7%) IF grafts touched the roof without deformation (IRI type 2). The presence or absence of impingement was not statistically significant. The mean sagittal tibial tunnel guide pin position prior to drilling was 27.6% of the sagittal diameter of the tibia (range, 22%-33.9%). However, computed tomography performed postdrilling detected substantial posterior enlargement in 2 TT specimens. A significant difference in the sagittal graft angle was noted between the 2 groups. TT grafts were more vertical, leading to angular convergence with the roof, whereas IF grafts were more horizontal and universally diverged from the roof.Conclusion:The IF technique had no specimens with roof impingement despite an anterior tibial tunnel position, likely due to a more horizontal graft trajectory and anatomic placement of the ACL femoral tunnel. Roof impingement remains a concern after TT ACL reconstruction in the setting of anterior tibial tunnel placement, although statistical significance was not found. Future clinical studies are planned to develop better recommendations for ACL tibial tunnel placement.Clinical Relevance:Graft impingement due to excessively anterior tibial tunnel placement using a TT drilling technique has been previously demonstrated; however, this may not be a concern when using an IF tunnel drilling technique. There may also be biomechanical advantages to a more anterior tibial tunnel in IF tunnel ACL reconstruction.

Comparison of Anterior Cruciate Ligament Graft Isometry between Paired Femoral and Tibial Tunnels.

Accurate tunnel placement is important for a successful anterior cruciate ligament (ACL) reconstruction. Controversy exists concerning the preferred method of femoral tunnel preparation, with proponents of both medial portal and transtibial drilling techniques. Current ACL literature suggests that placement of the femoral ACL attachment site posterior or "low" in the ACL footprint leads to more anatomically correct ACL mechanics and better rotational control. There is limited literature focusing on ACL graft displacement through knee range of motion based on specific paired placement of femoral and tibial tunnels. Our purpose was to assess ACL isometry between multiple combinations of femoral and tibial tunnels. We hypothesized that placement of the graft at the posterior aspect of the ACL footprint on the femur would be significantly less isometric and lead to more graft displacement as compared with central or anterior placement. The ACL of matched pairs of cadaveric knees was arthroscopically debrided while leaving the soft tissue footprint on the femur and tibia intact. One knee from each pair underwent notchplasty. In all knees, three femoral and three tibial tunnels were created at the anterior, central, and posterior aspects of the ACL footprint. A suture was passed through each tunnel combination (nine potential pairs), and the change in isometry was measured throughout full knee range of motion. Placement of the femoral tunnel along the posterior aspect of the ACL footprint was less isometric compared with a central or anterior position in the femoral footprint. Placement of a posterior tibial tunnel also led to decreased isometry, but tibial tunnel placement affected isometry to a lesser extent than femoral tunnel placement. The combination of a posterior femoral and posterior tibial tunnel resulted in greater than 1 cm of graft excursion from full flexion to extension. Placement of ACL tunnels at anisometric sites may adversely affect the mechanical properties and behavior of the ACL graft, resulting in either graft laxity in flexion or overconstraint and loss of extension.

Anatomic Tunnel Placement in Anterior Cruciate Ligament Reconstruction.

The anatomic anterior cruciate ligament (ACL) reconstruction concept has developed in part from renewed interest in the insertional anatomy of the ACL, using surgical techniques that can reproduce this anatomy reliably and accurately during surgical reconstruction. Several technical tools are available to help identify and place the tibial and femoral grafts anatomically, including arthroscopic anatomic landmarks, a malleable ruler device, and intraoperative fluoroscopy. The changes in technique for anatomic tunnel placement in ACL reconstruction follow recent biomechanical and kinematic data that demonstrate improved time zero characteristics. A better re-creation of native ACL kinematics and biomechanics is achieved with independent femoral drilling techniques that re-create a central footprint single-bundle ACL reconstruction or double-bundle reconstruction. However, to date, limited short-term and long-term clinical outcome data have been reported that support using either of these techniques rather than a transtibial drilling technique. This lack of clear clinical advantage for femoral independent and/or double-bundle techniques may arise because of the potentially offsetting biologic incorporation challenges of these grafts when placed using these techniques or could result from modifications made in traditional endoscopic transtibial techniques that allow improved femoral and tibial footprint restoration.

Physeal Disruption During ACL Reconstruction in Skeletally Immature Patients

Objectives:The purpose of this study was to radiographically assess differences in distal femoral physeal disruption between transtibial and independent femoral tunnel drilling techniques following ACL reconstruction in skeletally immature patients.Methods:A retrospective, matched comparative cohort study was performed of skeletally immature patients who underwent transphyseal ACL reconstruction between January 1, 2008 and March 31, 2011. All skeletally immature patients between ten and fifteen years old who underwent independent femoral tunnel drilling and had adequate baseline and post-operative radiographs were analyzed. These patients were matched with a transtibial technique cohort based on age and sex. Demographic characteristics and peri-operative metrics were collected. Radiographic measurements were recorded from pre-operative MRI and post-operative plain radiographs.Results:Twenty patients were analyzed. Between groups, there were significant differences between independent tunnel drilling and transtibial tunnel drilling in the estimated area of physeal disruption (1.64 cm2 vs. 0.74 cm2, P<0.001), femoral (32.1º vs. 72.8º, P<0.001) and tibial (50.1º vs. 60.5º, P=0.003) tunnel angles, medial/lateral location of the femoral tunnel (24.2 mm vs. 36.1 mm from lateral cortex, P=0.001), and distance from the lateral aspect of the distal femoral physis and the femoral tunnel exit (4.7 mm vs. 26.7 mm from the perichondrial ring, P<0.001), respectively. All patients who underwent femoral tunnel drilling at an angle of less than 25º from the transverse axis experienced a greater than 6% disruption of physeal area. There was a significant inverse correlation between femoral tunnel angle and estimated area of femoral physeal involvement (r=-0.8255, P=0.003).Conclusion:With femoral tunnel drilling techniques that create more oblique tunnels, the area of distal femoral physeal damage is larger, more eccentric and closer to the perichondrial ring. Since most studies noting the safety of transphyseal ACL reconstruction have utilized a vertical femoral tunnel, surgeons should be aware that if an independent femoral tunnel drilling technique is utilized during transphyseal ACL reconstruction, the physis is at greater risk when drilling at more horizontal angles. Angles greater than 25º from the transverse axis may safely create <6% physeal area damage.

Anatomic assessment of femoral tunnel by transtibial drilling technique in double-bundle anterior cruciate ligament reconstruction: an in vivo study

ObjectiveTo evaluate the anatomy of femoral tunnels created by simulated transtibial technique in double-bundle anterior cruciate ligament (ACL) reconstruction. MethodsTwo tibial tunnels, anteromedial (AM) and posterolateral (PL), were drilled 45° and 55° to tibial plateau respectively. On the femoral side, the AM and PL tunnels were drilled through anteriomedial portal. After the four tunnels were established, the shaft of a reamer was introduced into the joint through tibial tunnel and reached against the lateral wall of intercondylar notch. The position that the reamer shaft can reach was marked and recorded. ResultsNeither femoral AM nor PL tunnel opening can be fully or partially reached by the reamer shaft through the tibial AM tunnel in all cases. The evaluation through the tibial PL tunnel showed that only in 8 of 50 cases (16%) the femoral AM tunnel opening and in 4 cases (8%) the PL opening can be fully reached. On the other hand, in 12 cases (24%) the femoral AM tunnel opening and in 10 cases (20%) the PL opening can be partially reached by the shafts through the tibial PL tunnel. ConclusionThe result strongly suggests that transtibial technique is not well competent for femoral tunnel drilling in anatomic double-bundle ACL reconstruction as we have hypothesized.

Inside-Out Antegrade Tibial Tunnel Drilling Through the Posterolateral Portal Using a Flexible Reamer in Posterior Cruciate Ligament Reconstruction

Posterior cruciate ligament (PCL) reconstruction using the transtibial drilling or arthroscopic tibial-inlay technique has a risk of injury to the popliteal neurovascular bundle because a pin is drilled anterior to posterior. Intraoperative fluoroscopy is used to decrease the risk of neurovascular injury. In addition, graft passage in the transtibial technique may be problematic because of a sharp turn when placing the graft into the tibial tunnel, which may damage graft fibers. In the surgical technique described in this report, the posteromedial portal is used for visualization and the posterolateral portal is used for debridement of the PCL tibial footprint and the synovial fold closest to the PCL. A curved guide is placed from the posterolateral portal to the tibial footprint, and a flexible pin is drilled across the tibia. The tibial tunnel is then created using a flexible reamer under direct visualization up to the desired length, and a graft can be positioned in the tibial tunnel through the posterolateral portal. This technique has the potential advantages of decreasing the risk of injury to the popliteal neurovascular bundle (use of anteriorly directed, inside-out drilling), avoiding a sharp turn during graft passage, and allowing accurate and anatomic tibial tunnel placement without intraoperative fluoroscopy.

ACL Roof Impingement Revisited

Objectives:Anatomic femoral tunnel placement for single-bundle ACL reconstruction is now well accepted. The ideal location for the tibial tunnel, however, has not been studied extensively. A wide range of anterior to posterior (A-P) tibial tunnel locations are considered acceptable. Biomechanical data suggests that the anterior fibers of the native ACL are more functional. Similarly, ACL grafts placed more anteriorly in the footprint have resulted in improved clinical results in at least one study. However, the concern for intercondylar roof impingement has tempered enthusiasm for a more anterior tibial tunnel placement. Investigations by Howell and others on roof impingement have focused only on the transtibial technique. Our study seeks to characterize intercondylar roof impingement in a 3-D cadaveric model with both transtibial and independent femoral tunnel drilling techniques in the setting of an anteriorly positioned tibial tunnel.Methods:Twelve fresh frozen cadaver knees (six matched pairs) were randomized to either a transtibial or an independent femoral (IF) drilling technique. Tibial guide pins were placed in the anterior half of the ACL tibial footprint following arthroscopic debridement of the native ACL. A fluoroscopic calculation of the tibial guide pin location using the technique described by Staubli was used to ensure a relatively anterior position of the tibial tunnel (Staubli < 35). All efforts were made to place the femoral tunnel anatomically in the center of the footprint. An 8 mm Gore-Tex smoother was passed into the knee to function as a radiopaque surrogate graft, and the knees then underwent computed tomography in maximal extension. Graft-visualized 3D-CT reformatting was used to evaluate for roof impingement by analyzing the Impingement Review Index (IRI) as described by Iriuchishima. Tunnel morphology, knee flexion, and intra-articular graft angles were also recorded.Results:Two grafts (2/6, 33.3 %) in the TT group impinged upon the intercondylar roof and sustained an angular deformity (IRI Type 1) Figure 1. No grafts in the IF group impinged; 4/6 (66.7%) grafts in the IF group touched the roof but did not deflect (IRI Type 2). The average tibial tunnel fluoroscopic Staubli ratio was 31.9 (range 22 - 39). The impinging TT grafts had an average Staubli ratio of 29.4 while the non-impinging TT grafts had more posterior tibial tunnels (Staubli 38). This did not reach statistical significance. All other grafts avoided contact with the roof (IRI Type 3). Two tibial tunnels in the TT group migrated posteriorly more than 6 mm after femoral tunnel drilling, and this may have prevented graft impingement. No significant differences were found between the tibial tunnel locations in the IF group.Conclusion:The independent femoral drilling technique appears to have a low risk for roof impingement in the setting of anterior tibial tunnel positioning, likely because of more favorable graft trajectory afforded by an anatomic femoral tunnel that lies below Blumensaat's line. Roof impingement remains a concern after transtibial ACL reconstruction with a more anterior tibial tunnel. An unintended protective effect may occur during transtibial drilling that expands the tibial tunnel posteriorly. Future clinical studies are planned to develop better recommendations for ACL tibial tunnel placement.

Radiologic and Clinical Evaluation of Anatomic and Transtibial ACL Reconstruction in a Population Excluding Professional Athletes

Objectives:Two different approaches for drilling the femoral tunnel are commonly used in single-bundle anterior cruciate ligament (ACL) reconstruction: creating the femoral tunnel through the tibial tunnel or drilling the tunnel through a low anteromedial portal. The purpose of this retrospective study was to compare the radiological and clinical outcomes of hamstring ACL reconstruction using the transtibial (TT) versus the anteromedial portal (AM) technique for drilling the femoral tunnel by two different surgeons in non-professional athletes.Methods:Using the elevator system with hamstring tendons, single-bundle ACL reconstruction was applied to 24 patients with the TT technique and to 15 patients with the AM technique. Radiological outcome was evaluated by the postoperative X-rays and MRI images at the 6-9 month and clinical outcomes by the modified Cincinnati Knee Score. The angle made by the tunnel with the anatomic axis of the femur (FTA) and the angle made by the tunnel with the anatomic axis of the tibia (TTA) were examined on direct radiographs and the angular difference between the tunnels was evaluated. On MRI, evaluation was made of the anterior length in the sagittal plane of the exit point of the tibial tunnel in the joint (TAS) in ratio to the whole plateau (TSR) and the posterior length in the sagittal plane of the entrance point of the femoral tunnel in the femoral lateral condyle (FPS) in ratio to the anterior posterior diameter of the whole condyle (FCR) and the height of the lateral condyle location in the sagittal plane (FH).Results:The FH height ratio of the TT group was statistically significant when compared to the AM group (p<0.01). No statistically significant difference was found between the groups in respect of FPS (p>0.05). The mean femoral tunnel angle of the AM group was statistically significant compared to that of the TT group (p<0.01). The mean tibial tunnel angle of the TT group was statistically significant compared to that of the AM group (p<0.01). The angular difference of the AM group was statistically significant compared to that of the TT group (p<0.01). In both the AM and TT groups, the increase seen in the postoperative clinical scores compared to the preoperative scores was determined to be statistically significant (p<0.01). No statistically significant relationship was determined in either the AM group or the TT group between the postoperative clinical scores and the femoral tunnel angle, the tibial tunnel angle and the angular difference (p>0.05).Conclusion:When using a transtibial drilling technique, the location of the femoral tunnel is restricted by the angulation of the tibial tunnel in the coronal plane and may lead to a high placement of the femoral tunnel in a non-anatomical position. The use of the anteromedial portal (AMP) for the femoral drilling provides the surgeon with more freedom to anatomically place the tunnel in the natural femoral ACL footprint, thus improving rotational stability. In this early stage study of individuals not participating in professional sports, although a significant difference was seen in favour of the anatomic group, in the radiological measurements between the anatomic and transtibial groups, no significant difference was determined in respect of clinical results. This can be considered to be due to a low requirement for rotational stability in individuals who do not participate sports.

Transtibial Versus Anteromedial Portal Anterior Cruciate Ligament Reconstruction Using Soft-Tissue Graft and Expandable Fixation

To compare clinical outcomes between transtibial drilling and anteromedial portal techniques for anterior cruciate ligament (ACL) reconstruction using soft-tissue grafts secured with expandable fixation. Patients undergoing soft-tissue ACL reconstruction using expandable fixation between 2007 and 2011 were reviewed for inclusion in this study. Revision ACL cases were excluded. All surgeries were performed by 1 of 2 sports medicine fellowship-trained surgeons (T.S.D., K.D.M.). A total of 128 patients (67 comprising transtibial cohort and 61 comprising anteromedial portal cohort) had a minimum of 24 months' follow-up (mean, 27 months) and met the inclusion criteria. The patients were divided into 2 groups based on the method used for creation of the femoral tunnel. At final follow-up, outcomes were assessed with KT-1000 (MEDmetric, San Diego, CA) measurements, as well as International Knee Documentation Committee, Lysholm, and Tegner scores. Data were screened for normality and skew before use of parametric statistics and were transformed if necessary. Data were analyzed by 1-way analysis of variance with post hoc paired comparisons using the Bonferroni approximation. No differences in demographic characteristics were observed between the 2 groups. There was no significant difference in postoperative KT-1000 measurements between the 2 cohorts (1.571 ± 0.2275 mm in transtibial cohort [n = 35] and 1.246 ± 0.09249 mm in anteromedial cohort [n = 61], P = .1259). A significant improvement in International Knee Documentation Committee scores was observed in the anteromedial cohort, increasing from 41 ± 16 to 89 ± 7.4 (mean ± SD) (P < .0001). Similar changes were observed for the Lysholm score. There was no significant difference between cohorts for any postoperative scores measured (P > .2). Our data show comparable KT-1000 measurements for both anteromedial and transtibial femoral drilling techniques when using a soft-tissue graft with expandable fixation. Level IV, therapeutic case series.

A randomized prospective controlled study with 5-year follow-up of cross-pin femoral fixation versus metal interference screw fixation in anterior cruciate ligament reconstruction.

The purpose of this study was to determine and compare mid- to long-term results of cross-pin versus metal interference screw fixation of ACL graft. In a prospective trial, 62 patients were randomized into two groups based on method of fixation. Transtibial drilling technique was used in the cross-pin and outside-in femoral drilling in the interference screw fixation group. Clinical and radiographical outcomes were assessed 2 and 5years postoperatively. The study showed no clinically significant difference with respect to method of graft fixation. Mean anteroposterior side-to-side instrumented laxity difference was 2.4mm in the cross-pin group and 2.5mm in the screw group (n.s.). Median Tegner and mean Lysholm scores at 5years were 6 (range 3-9) and 92.2 (range 69-100) in the screw group and 7 (3-10) and 93.3 (82-100), respectively, in the cross-pin group. Radiographical osteoarthritis increased in both groups from 2 to 5years after reconstruction (p<0.05), especially in the medial and patellofemoral joint spaces. Widening of the drill tunnels continued from 2 to 5years without clinical significance. The method of graft fixation did not yield a difference in clinical or radiographical outcome at 5years. Results were excellent in both groups. I.

Transtibial Tunnel Placement in Posterior Cruciate Ligament Reconstruction: How It Relates to the Anatomic Footprint.

Background:It is common to place the posterior cruciate ligament (PCL) tibial tunnel with a transtibial technique using a guide that attempts to place the center of the tunnel 1 to 1.5 cm distal to the tibiofemoral joint. It is unknown how well this technique will re-create the native tibial footprint of the PCL.Purpose:To evaluate the accuracy of tibial tunnel placement using a transtibial technique.Study Design:Controlled laboratory study.Methods:Ten cadaveric knees from 10 donors underwent arthroscopic transtibial drilling of the tibial tunnel with use of a posteromedial portal for visualization. The transtibial guide was rested flush against the tibial spines to allow for the guide to be as distal as possible, which was between 1 and 1.5 cm distal to the tibiofemoral joint line. Using this technique, an attempt was made to place the tibial tunnels as close to the center of the PCL footprint as possible. All knees underwent computed tomography both pre- and postoperatively with a previously reported technique optimized for ligament evaluation. This allowed comparison of the anatomic PCL 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.Results:The percentage of tunnel aperture contained within the native footprint was 45.9% ± 23.1%. The distance from the center of the tibial tunnel aperture to the center of the tibial PCL footprint was 6.4 ± 2.3 mm. The tunnels were almost always (9/10) distal (or inferior) to the native footprint and either slightly lateral (5/10) or centered (5/10) in a medial to lateral direction.Conclusion:This study demonstrates that using the transtibial drilling technique in the tibia for PCL reconstruction places approximately half of the tibial tunnel aperture within the tibial footprint. Generally, the tunnel is distal to the footprint.Clinical Relevance:Consideration should be given to the fact that, using this transtibial technique, the tibial tunnel aperture is generally not placed in the center of the footprint. This may not be a negative issue, however, since there are other potential advantages from distal tunnel placement.