Anatomic Femoral Tunnel Placement Research Articles

Anatomical single bundle anterior cruciate ligament reconstruction using the hamstring tendon graft to restore knee function in patients with sport injury, falling trauma or road traffic accident

The purpose of this study was to evaluate the effect of anatomic single bundle ACL reconstruction using the hamstring tendon to restore knee function in patients with anterior cruciate ligament (ACL) injury. This was a prospective study with 30 patients (3 women and 27 men, aged 20-40 years) who underwent the arthroscopic single bundle ACL reconstruction using semi-tendinosus and gracilis autograft fixed with an interference screw with anatomical femoral tunnel placement at the Orthopaedic Surgery Department of Sohag University Hospital. All patients were followed up at 2 weeks, 6 weeks, 3 months and 6 months to assess their progress in the rehabilitation program and to address any complications. They were examined preoperatively for knee stability and associated injuries (i.e., meniscal injury), knee X-ray and MRI. All patients were assessed using the Lysholm score, the IKDC score, the Lachman score, and the pivot shift score preoperatively and six months postoperatively, and the results were compared. For data analysis, we used the Statistical Program for the Social Sciences (SPSS). Our study showed highly statistically significant differences between the preoperative and postoperative Lysholm scores, the IKDC score, the Lachman score, and the pivot shift score in favor of the postoperative scores (p < 0.001**). Anatomic single bundle ACL reconstruction using the hamstring tendon is an effective technique for restoring knee function and in patients with deficient ACL.

Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study.

Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients. This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected. Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference). To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal.

Medial Patellofemoral Reconstruction Techniques for Patellar Instability

The medial patellofemoral complex (MPFC) is the term used to describe the primary soft tissue stabilizer of the patella, which consists of fibers that attach to the patella (medial patellofemoral ligament, or MPFL), and the quadriceps tendon (medial quadriceps tendon femoral ligament, or MQTFL). Despite the variability of its attachment on the extensor mechanism, the midpoint of this complex is consistently at the junction of the medial quadriceps tendon with the articular surface of the patella, indicating that either patellar or quadriceps tendon fixation can be used for anatomic reconstruction. Multiple techniques exist to reconstruct the MPFC, including graft fixation on the patella, quadriceps tendon, or both structures. Various techniques using several graft types and fixation devices have all reported good outcomes. Regardless of the location of fixation on the extensor mechanism, elements critical to the success of the procedure include anatomic femoral tunnel placement, avoiding placing undue tension on the graft, and addressing concurrent morphological risk factors when present. This infographic reviews the anatomy and techniques for the reconstruction of the MPFC, including graft configuration, type, and fixation, while addressing common pearls and pitfalls in the surgical treatment of patellar instability.

Computer-assisted navigation in ACL reconstruction improves anatomic tunnel placement with similar clinical outcomes

BackgroundWhile the use of navigation systems in anterior cruciate ligament (ACL) reconstruction theoretically improves tunnel placement accuracy and clinical outcomes, the existing literature remains inconclusive. We aimed to evaluate the potential benefits of navigated ACL reconstruction on tunnel placement and clinical outcomes. MethodsIn this retrospective study, we evaluated a cohort of patients who underwent conventional or navigated (OrthoPilot system) primary ACL reconstruction at our institution from June 2004 to October 2009. Anteroposterior and lateral radiographic knee assessments were evaluated to assess postoperative tunnel positioning. Clinical outcomes, including the International Knee Documentation Committee classification, Lysholm score, and Tegner score, were evaluated preoperatively and 1-year postoperatively. Radiographic and clinical outcomes were compared and analysed using independent 2-sample t-tests and Chi-square tests. ResultsSixty patients met the inclusion criteria and were included for analysis, comprising of 26 navigated and 34 conventional reconstructions. Postoperative radiographs showed no differences in tibial tunnel position between both groups, but a significantly smaller deviation from the recommended position in the navigated group (navigated: 5.96 %; conventional: 7.92 %; p = 0.008). Femoral tunnel placements in the navigated group were significantly more perpendicularly away from the Blumensaat line (navigated: 38.90 %; conventional: 31.94 %; p = 0.001), with a greater deviation from recommended position (navigated: 11.00 %; conventional: 6.94 %; p = 0.009). There were no differences in 1-year postoperative clinical outcomes (p > 0.05). ConclusionNavigated ACL reconstruction resulted in a more anatomic femoral tunnel placement and similar clinical outcomes as conventional reconstruction. Further research should be conducted to clarify the potential biomechanical and clinical impacts of navigated ACL reconstruction.

Central femoral tunnel placement can reduce stress and strain around bone tunnels and graft more than anteromedial femoral tunnel in anterior cruciate ligament reconstruction.

The present study investigated the effects of anteromedial (AM) and central femoral footprint placement on stress and strain distribution around the femoral and tibial tunnel and graft following anterior cruciate ligament reconstruction (ACLR). A three-dimensional (3D) reconstructed knee model was validated and used for simulating ACLR by finite element analysis. A combined loading during normal human walking was applied to the knee models using different anatomic femoral tunnel placement at 20° knee flexion. The results of von Mises stress and principal strain at the entrances of the femoral and tibial tunnel and ACL graft was determined. The peak von Mises stress and the maximum principal strain in the AM footprint group were 8.78 MPa and 8850.89 μ-strain at the entrance of femoral tunnel, and 5.29 MPa and 5553.27 μ-strain at the entrance of tibial tunnel. The results in the AM footprint group were higher than that in the central footprint group. The peak von Mises stress around the ACL graft following AM footprint ACLR was 28.63 MPa, higher than that following the central footprint ACLR. The AM footprint ACLR generated more significant peak von Mises stress and maximum principal strain around the entrances of femoral and tibial tunnel and the graft than the central footprint. The present results are of clinical relevance as they can provide a better understanding of tunnel enlargement and graft failure.

Comparison of Inside-Out and Outside-In Methods of Femoral Tunnel Preparation in Anterior Cruciate Ligament (ACL) Reconstruction Using 3D-CT.

IntroductionAnterior cruciate ligament (ACL) reconstruction techniques continue to evolve and the need to address the more anatomical femoral tunnel placement of the graft is critical, and in our study, we assessed the placement of femoral tunnel via transportal and retrograde drilling techniques.Material and methodsSixty patients where n=31 for retrograde, n=29 for transportal were assessed via CT knee for the femoral tunnel aperture on the intercondylar ridge via high low and deep shallow direction ratio and interpreted accordingly.ResultsIn our study, the femoral tunnel done via transportal method (n=29) has a deep shallow ratio range of 22%-47% and mean of 31.9±6.5, and graft is anatomical in 79%. The femoral tunnel done via the retrograde method (n=31) has a deep shallow depth ratio range of 11%-41% with a mean of 27.5±6.5 and graft is anatomical in 77% of the study group and the p-value means the ratio is 0.01 (significant). The femoral tunnel done via transportal method (n=29) has a high low ratio range of 19%-45% and mean of 32.9±6.3 and graft is anatomical in 72%. The femoral tunnel done via the retrograde method (n=31) has a deep shallow depth ratio range of 20%-38% with a mean of 33.9±4.1 and graft is anatomical in 94% of the study group with a p-value mean ratio being 0.51 (insignificant).ConclusionWatch out for the femoral tunnel placement in a deep shallow direction while going for standard transportal technique and high low direction while performing retrograde technique.

J arch: A contemporary soft-tissue landmark for anatomic placement of femoral tunnel in remnant-preserving anterior cruciate ligament (ACL) reconstruction

Objectives: Femoral tunnel placement is a critical step in ACL reconstruction surgery. Surgeons usually end up clearing the soft tissue to access the bony landmarks. Biological ACL reconstruction with preservation of soft tissue can be done with reliable soft tissue landmarks. Our objective is to assess the reliability of a soft tissue landmark- femoral ACL remnant, for appropriate femoral tunnel placement in soft tissue preserving ACL reconstruction. Materials and Methods: This study was a retrospective analysis of prospectively collected data of 40 consecutive patients who underwent primary ACL reconstruction in January 2018 by a single surgeon. An inverse J shaped tissue arch was identified and used as soft tissue landmark for anatomic placement of femoral tunnel. This arch was a part of femoral ACL remnant. MRI films were examined post-operatively to determine the position of the femoral tunnel. Postoperatively, MRI of these patients were reviewed to evaluate the femoral tunnel position in terms of depth and height from the proximal condylar surface and notch roof, respectively. Results: The center of the femoral tunnel was found to be at a mean depth of 27.12 ± 2.2% from the proximal condylar surface (parallel to Blumensaat’s line) and a mean height of 30.96 ± 2.75% from the notch roof (perpendicular to Blumensaat’s line), which is at par with previously defined data given by various studies. Conclusion: J arch can be used as a dependable soft tissue landmark and a guide for the anatomic placement of femoral tunnel in biological ACL Reconstruction.

Functional outcome following arthroscopic ACL reconstruction using 4 stranded hamstring autograft and preservation of hamstring graft at tibial insertion

Background: The technique of arthroscopic anterior cruciate ligament reconstruction (ACLR) has undergone many modifications in the recent times with improved understanding of anatomy, kinematics, and biology of the graft. In this study, we evaluated the functional outcome following arthroscopic single bundle ACLR with tibial attachment preserving quadrupled hamstring autograft without implant on the tibial side.Results: There is a statistically significant increase in both IKDC and Lysholm score from preoperative/pre injury to post-operative assessment at minimal 9 month follow up.The mean pre injury Tegner score was 5.7 ± 1.194 and mean post injury Tegner score was 5.2 ± 1.055. The mean pre injury lysholm score was 97.9 ± 2.308 which at minimum 9 month follow-up was 88.3 ± 8.036. Out of 52 patients 37 of the patients (71.2%) were able to return to their pre injury activity including to recreational and to competitive sports. 5 patients (9.6%) had a drop of 1 level in Tegner activity level from there pre injury level of activity. 7 patients (13.5%) had a drop of 2 level in Tegner activity level from there pre injury level of activity. 2 patients (3.8%) had a drop of 3 level in Tegner activity level from there pre injury level of activity. 1 case reported a 4 level drop from pre injury levelsConclusion: Arthroscopic single-bundle ACL reconstruction using 4 stranded hamstring autograft, anatomic femoral tunnel placement and preservation of hamstring graft tibial insertion gives excellent to good functional outcome. Tibial attachment preserving hamstring graft without a tibial implant is a simple, time saving and cost effective technique that provides a consistently satisfactory outcome.

Clinical outcome of anterior cruciate ligament reconstruction with modified transtibial and anteromedial portal

Arthroscopic ACL reconstruction is the current standard care of treatment for anterior cruciate ligament (ACL) injuries. Modified transtibial (mTT) and anteromedial portal (AMP) techniques aim at the anatomical placement of femoral tunnel. Controversy existed in the literature with regard to the outcome of these techniques. Hence, we designed a retrospective comparative study to analyse the clinical and functional outcomes of mTT and AMP techniques. We hypothesized that there would be no difference between the clinical and functional outcomes in mTT and AMP techniques. This retrospective observational study was conducted in consecutive patients who underwent arthroscopic ACL reconstruction using semitendinosus-gracilis (STG) quadrupled graft in our tertiary care centre with a minimum follow-up of two years. Out of 69 patients, 37 had undergone ACL reconstruction by mTT technique and remaining by AMP technique. All the patients were assessed clinically by anterior drawer, Lachman’s, pivot shift and single-legged hop test. Lysholm Knee Scoring Scale and International Knee Documentation Committee (IKDC) subjective knee evaluation score were used for the functional status. Knee instability was assessed objectively by KT-1000 arthrometer. There was no statistically significant difference in baseline demographic characteristics between mTT and AMP groups. At the end of 2 years, no statistically significant difference was noted in the anterior drawer and Lachman’s test. Though not significant, IKDC scores and Lysholm’s scores showed a better outcome in the AMP group when compared to the mTT group. AMP group showed significantly better outcome with KT-1000 arthrometer. Based on the results obtained, we presume that overall both mTT and AMP have similar functional outcome. However, as AMP technique offers significantly improved subjective rotational stability on pivot shift test, better hop limb symmetry index and KT 1000 readings compared to mTT, we suggest AMP over mTT.

Usage of Accessory Anteromedial Portal for Anatomical Placement of Femoral Tunnel in Transportal Anterior Cruciate Ligament Reconstruction: A Prospective Study.

Background and objectiveThe anterior cruciate ligament (ACL) has an essential role in preserving the function and stability of the knee joint. It acts primarily to prevent anterior tibial translation. Arthroscopic ACL reconstruction using quadrupled hamstring graft is the widely practiced modality for treating ACL injuries nowadays. The objective of this study was to assess the functional outcomes of ACL reconstruction using the transportal approach for a femoral tunnel through an accessory anteromedial portal (AAM).Materials and methodsThis prospective study included 35 patients who met the inclusion criteria. All patients underwent arthroscopic reconstruction of ACL using quadrupled hamstring tendon graft via transportal technique for femoral canal reaming through AAM. Patients were assessed for the functional outcome for a year using the Tegner-Lysholm knee scoring system.ResultsThe analysis of the studied cases revealed that the mean age of the patients was around 27 years. Males were affected more than females. The left side (77.14%) was affected more than the right side (22.86%); 54.28% of patients had a history of road traffic accidents (RTAs). Preoperatively, 19 (54.28%) patients had poor and 16 (45.72%) patients had fair Tegner-Lysholm scores. After one year of follow-up, 29 (82.85%) of the patients had an excellent score as per the Tegner-Lysholm scoring system. Three patients had knee pain and thigh muscle wasting (2-3 cm), and two of them also had a sense of giving away during follow-up.ConclusionAnatomical reattachment of tendon graft for ACL reconstruction at femoral and tibial footprints is indispensable for good functional outcome and knee kinematics, and the usage of the AAM provides good visualization of femoral footprint and ease to surgeons during ACL reconstruction for making a near-accurate femoral tunnel and thereby achieving better outcomes.

Iatrogenic Injury to the Posterolateral Knee During Anterior Cruciate Ligament Reconstruction with Anteromedial Portal Technique

BACKGROUND: Femoral tunnel reaming through anteromedial portal, also known as transportal technique, allows for anatomic femoral tunnel placement in restoring anterior cruciate ligament (ACL) kinematics. This procedure may cause iatrogenic injury to the posterolateral structures of the knee.&#x0D; PURPOSE: This study aims to assess the risk of posterolateral structure injury in ACL reconstruction using transportal technique.&#x0D; METHODS: ACL reconstruction using transportal technique was performed in 20 patients. Clinical and radiological examination was performed preoperatively and 1 month postoperatively. Clinical examination included any pain or paresthesia on posterolateral area of the knee, varus alignment of the knee, abnormal gait, and specific tests for posterolateral stability. Radiological evaluation was plain radiography and stress radiography for posterolateral stability, and magnetic resonance imaging (MRI) for assessing structural damage.&#x0D; RESULTS: Post-operative evaluation showed pain in posterolateral area in five patients, numbness on posterolateral knee in one patient, both pain and numbness in two patients and lateral gastrocnemius muscle injury on MRI in six patients. We did not find varus knee alignment and abnormal gait. Specific tests were negative in post-operative evaluation. Post-operative radiographic imaging did not show the sign of lateral widening.&#x0D; CONCLUSION: Femoral tunnel drilling using transportal technique in ACL reconstruction is safe even it might risk to damage lateral gastrocnemius muscle, according to clinical and MRI findings.

A comparative study between transtibial and anatomical arthroscopic anterior cruciate ligament reconstruction of knee

Introduction: Knee injuries are very common due to sports and repetitious activities. Of these ACL injuries are the most common. Surgical treatment with ACL reconstruction has now become gold standard in management of ACL injury. The main aim in anterior cruciate ligament surgery is to reproduce the normal kinematics of the knee and provide stability in the sagittal and coronal plane. There is better patient satisfaction associated with better stability and kinematics. The objective of our study is to compare the results of outcome following ACL reconstruction using the transtibial and the anatomical technique or femoral tunnel placement. Results: Out of 50 cases 38 were males 12 were females. Right knee was commonly involved compared to left accounting for 52% cases. Young patients between 17 and 35 years constituted the maximum number who suffered from ACL injuries. 60% of cases were due to motor vehicular accidents (MVA). Post injury there was an average fall of 50% in activity levels as compared to pre injury levels in both the groups. The patients in anatomical group attained 86.36% of pre injury activity level on an average, while those in transtibial group achieved 63.87%, a difference of 25.56%. There was a difference of a significant 19.40% in both group Lysholm Tegner Knee score with anatomical group having 90.92% and transtibial having 73.28% of score. Interpretation and conclusion: The anatomical ACL reconstruction group performed better in subjective outcome of Lysholm Tegner Knee Score as well as in achieving greater percentage of pre injury activity level as compared to the transtibial group of ACL reconstruction. Hence anatomical placement of femoral tunnel using anteromedial accessory portal is a better surgical option when compared to transtibial femoral tunnel placement in ACL reconstruction surgeries to achieve a more near normal knee kinematics.

Functional outcome of transtibial VS transportal drilling techniques in anterior cruciate ligament reconstruction

Background: Anterior Cruciate ligament injuries are one of the most common injuries of the knee. The choice of the optimal surgical method in ACL reconstruction is still unclear. A frequent cause for failure after ACL reconstruction has been the incorrect placement of bone tunnels, especially on the femoral side. The most commonly employed trans-tibial technique has been reported not to provide anatomical placement of femoral tunnel and result in rotational instability. Cadaveric and radiographic studies have confirmed that drilling the femoral tunnel through anteromedial portal allows a more anatomical placement of the tunnel and higher rotational stability. However clinical results of trans-tibial and anteromedial portal techniques are still comparable. Objective: To study the functional outcome in transtibial vs transportal drilling techniques in ACL reconstruction. Materials and Methods: This is a prospective follow up study of functional outcome in 40 patients who underwent ACL reconstruction by either transtibial or transportal technique. Patients were followed up for at least 24 months and assessed using Lysholm and IKDC scale. Statistical Analysis of the data was done by Mann-Whitney test and chi square test. Results: In the present study the Trans-portal group of patients showed a marginally better functional outcome with respect to the Lysholm and IKDC scores; however the statistical significance was lacking. Conclusion: There isn’t enough clinical evidence to warrant giving up on transtibial technique which is time tested and simpler.

Evaluation of the Schöttle Technique in the Pediatric Knee.

Background:The Schöttle point is commonly used for anatomic femoral tunnel placement during medial patellofemoral ligament (MPFL) reconstruction. This technique has not been previously validated in the skeletally immature patient, in whom femoral tunnel placement may put the distal femoral physis at risk of iatrogenic injury.Hypothesis:Interobserver reliability for femoral tunnel placement will be higher in adult knees compared with pediatric knees.Study Design:Cross-sectional study (diagnosis); Level of evidence, 3.Methods:We selected 30 perfect lateral radiographs for this study: 20 from pediatric knees (mean patient age, 10 years; range, 8-11 years) and 10 from adult knees (mean patient age, 18.5 years; range, 18-23 years). Six observers with varying levels of clinical experience evaluated each radiograph and approximated the site of the MPFL femoral tunnel using the Schöttle technique. Intra- and interobserver reliabilities for femoral tunnel placement were evaluated. Statistical analysis was used to compare measurements.Results:During initial interobserver measurements, the diameter of the composite perfect circles averaged 9.0 and 6.8 mm in adult and pediatric knees, respectively (P = .004). At repeat measurement, circles averaged 9.8 and 7.3 mm in adult and pediatric knees, respectively (P = .0001). Femoral tunnel placement intraobserver variance averaged 2.9 mm in adult knees (range, 1.9-4.0 mm) and 2.3 mm in pediatric knees (range, 1.9-2.9 mm). This difference was not significant (P = .14).Conclusion:This study demonstrated that interobserver variance is actually greater in adult knees compared with pediatric knees, although interobserver variance was significantly different for both populations. Additionally, intraobserver variance is small on repeat measures, demonstrating that the Schöttle technique is reproducible for individual observers. Sources of this increased variance between observers are differences in agreement on the bony landmarks required for the Schöttle technique. Due to this variability in tunnel placement, we recommend caution when the Schöttle technique is used in pediatric knees to avoid iatrogenic injury to the distal femoral physis during femoral tunnel placement.

Radiographic Location Does Not Ensure a Precise Anatomic Location of the Femoral Fixation Site in Medial Patellofemoral Ligament Reconstruction.

Background:A frequently used method to determine the anatomic femoral fixation point in the operating room during medial patellofemoral ligament (MPFL) reconstruction is the radiographic method. However, the ability of this radiological method to establish an anatomic femoral attachment point might not be as accurate as expected.Purpose:(1) To evaluate the accuracy of the radiological method to locate the anatomic femoral fixation point in MPFL reconstruction surgery and (2) to determine the factors influencing the predictability of this method to obtain this objective.Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:A total of 100 consecutive 3-dimensional computed tomography (3D CT) knee examinations were performed at 0° of extension in 87 patients treated for chronic lateral patellar instability. For each knee, 2 virtual 7 mm–diameter femoral tunnels were created: 1 using the adductor tubercle as a landmark (anatomic tunnel) and the other according to the radiological method described by Schöttle et al (radiographic tunnel). We measured the percentage of overlap between both tunnels. Moreover, of the 100 included knees, 10 were randomly selected for a variability study.Results:Considering an overlap area greater than 50% as reasonable, the radiographic method achieved this in only 38 of the 100 knees. Intrarater and interrater reliability were excellent. There was a trend for female patients with severe trochlear dysplasia to have less overlap. This model accounted for 64.2% of the initial variability in the data.Conclusion:An exact anatomic femoral tunnel placement could not be achieved with the radiographic method. Radiography provided only an approximation and should not be the sole basis for the femoral attachment location. Moreover, in female patients with severe trochlear dysplasia, the radiographic method was less accurate in determining the anatomic femoral fixation point, although differences were not statistically significant.

EFFECT OF BONE TUNNELS POSITIONING ON OUTCOMES OF TRANSTIBIAL ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Purpose of the study — to evaluate position of bone tunnels after transtibial anterior cruciate ligament reconstruction (ACLR) and to determine the relationship of outcomes on their localization.Material and methods. 54 patients in follow up from 25 to 57 months after transtibial ACLR with hamstring tendons. In all patients was performed magnetic resonance imaging (MRI) to evaluate structure of graft. Bone tunnels localization was determined by computed tomography with three-dimensional reconstruction. Subjective score evaluation was performing by scales IKDC-2000, KOOS, Lysholm. Knee laxity was measured by anterior drawer, Lachman, pivot-shift tests and with arthrometr. Patient was separated in groups depending on the localization of the femoral tunnel for lateral intercondylar ridge (1 group — center of femoral tunnel in front of the LIR, 2 group — in zone of the LIR).Results. Tibial tunnel position in both groups of patients was the same and localized in central or back third of the footprint. The center of femoral tunnel in 32 patients (59%) was localized in front of the LIR (1 group), in other 22 (41%) — in proximal part of LIR (2 group). Clinical results show statistically significant differences between groups in knee stability and IKDC-2000. In 1 group 78% patients have knee instability grade 1 or 2, while in 2 group similar symptoms was in 32% patients. IKDC-2000 grade A were attributed 19% patients from 1 group and 64% from 2 group, rest of them was grade B or C.Conclusions. Transtibial anterior cruciate ligament reconstruction with hamstring tendons in most patients did not allow anatomical femoral tunnel placement. Clinical outcomes were much affected by the localization of bone tunnels.

The use of the 70° arthroscope for anatomic femoral and tibial tunnel placement in anterior cruciate ligament reconstruction.

The use of the 70° arthroscope for anatomic femoral and tibial tunnel placement in anterior cruciate ligament reconstruction.

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.

Proximity of Lateral Critical Structures to the All-Epiphyseal Outside-In Femoral Tunnels in Pediatric Anterior Cruciate Ligament Reconstruction

To describe the proximity of the lateral critical structures (peroneal nerve [PN], popliteus tendon [PT], lateral collateral ligament [LCL], and articular cartilage [AC]) to the femoral tunnel for outside-in all-epiphyseal anterior cruciate ligament (ACL) reconstruction in reference to knee flexion angle. All-epiphyseal ACL reconstructions were performed in 12 human cadaveric knees using arthroscopy and outside-in drilling for anatomic femoral tunnel placement that was ensured by identifying the center of the total ACL footprint. Fluoroscopy was used to confirm tunnel position and reconstructions were performed with quadrupled semitendinosus and gracilis autograft with Xtendobutton (Smith & Nephew, Andover, MA) fixation on the femoral side. After reconstruction, the lateral side of the knee was dissected and the LCL, PT, distal and posterior AC, and the PN were identified. The distances of these structures from the center of the exiting femoral tunnel were then measured using a digital caliper at 0°, 30°, 60°, 90°, and 120° of knee flexion. Any gross damage to these structures caused by the femoral drilling was also noted. Data were compiled and the mean and standard deviations (SD) of the distances from the pin to the structures of interest were calculated. The normality of the data at each flexion angle was assessed using Shapiro-Wilk tests (P > .05), and the relationship between flexion angle and average distance was evaluated using repeated measures analysis of variance (P < .05). Any significant relationships were then evaluated using paired t-tests (P < .05) with a Benjamini-Hochberg adjustment for each possible pair of flexion angles. Averages, SD, and P values are reported. A post hoc power analysis was performed. The violation of the LCL was noted in 3 specimens and that of the PT in 1 specimen as a result of femoral tunnel drilling at flexion angles ranging from 90° to 120°. The distance between the PT and the femoral tunnel also decreased significantly (P < .001) with knee flexion with average distances to the center of 8.07mm at 0°, 7.75mm at 30°, 6.33mm at 60°, 4.12mm at 90°, and 1.89mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the PT at 0° was 8.07 ± 7.15, at 30° 7.75 ± 6.66, at 60° 6.33 ± 6.79, at 90° 4.12 ± 5.71, and at 120° 1.89 ± 5.56. As the knee was progressively flexed, the distance between the LCL and the femoral tunnel decreased significantly (P < .001) with an average distance of 6.52mm at 0°, 6.26mm at 30°, 4.23mm at 60°, 2.38mm at 90°, and 0.4mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the LCL at 0° was 6.52 ± 5.93, at 30° 6.26 ± 7.32, at 60° 4.23 ± 7.82, 90° 2.38 ± 7.31, and at 120° 0.4 ± 7.01. The PN was remote from the femoral tunnel at all flexion angles with a mean distance of 42.83 to 59.22mm. The PN to guide pin distance increased significantly with progressive knee flexion (P<.001). The AC was not damaged in all specimens. The LCL and PT are at significant risk during percutaneous femoral drilling for all-epiphyseal anatomic ACL reconstruction using an outside-in technique. This risk was maximized at 120° flexion and minimized in full extension. These findings suggest that the optimal position for femoral drilling in all-epiphyseal ACL reconstruction is full or near-full extension of the knee that can be accomplished by placing the knee in 30° of flexion (after using fluoroscopic guidance to pass the guide pin past the lateral critical structures) to visualize the footprint of the ACL. Information garnered from this study may help clinicians better understand the risk to the lateral critical structures when an outside-in femoral tunnel is not drilled in the appropriate degree of knee flexion.

Anatomic Femoral and Tibial Tunnel Placement During Anterior Cruciate Ligament Reconstruction: Anteromedial Portal All-Inside and Outside-In Techniques

Tunnel malposition is one of the most common technical reasons for anterior cruciate ligament reconstruction failure. Small changes in tunnel placement can result in significant differences in outcome. More anatomic placement of the tunnels can lead to greater knee stability and a more accurate reproduction of native knee kinematics. This Technical Note describes 2 tibial tunnel–independent methods to obtain anatomic femoral tunnel placement. The all-inside anteromedial portal technique requires only minimal surgical incisions but allows precise femoral tunnel placement. However, hyperflexion of the knee is required, adequate surgical assistance is necessary, and this technique may be susceptible to graft-tunnel mismatch. The outside-in technique may be more beneficial in obese patients, skeletally immature patients, or revision cases. On the downside, it does require an additional 2-cm surgical incision. This article also provides surgical pearls to fine-tune tibial tunnel placement.