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.

306 Anterior Cruciate Ligament Graft Rupture: Analysis of Anteromedial Versus Trans-Tibial Portal Technique for Femoral Tunnel Placement in 473 Patients

Introduction Correct femoral tunnel position in anterior cruciate ligament reconstruction (ACLR) is critical in obtaining good clinical outcomes. We aimed to delineate whether any difference exists between the anteromedial and trans-tibial portal femoral tunnel placement techniques on the primary outcome of ACLR, graft rupture. Method Adult patients (>18 years old) who underwent primary ACLR between January 2011 - January 2018 were identified and divided based on portal technique (anteromedial v trans-tibail). The primary outcome measure was graft rupture. Univariate analysis was used to delineate association between independent variables and outcome. Binary logistic regression was utilised to delineate odds ratios of significant variables. Results 473 patients were analysed. Median age at surgery was 27 years old (range 18-70). 152/473 (32.1%) patients were anteromedial group compared to 321/473 (67.9%) trans-tibial. 25/473 (5.3%) patients sustained graft rupture. Median time to graft rupture was 12 months (IQR 9). A higher odd for graft rupture was associated with the anteromedial group, which trended towards significance (OR 2.03; 95% CI 0.90 - 4.56, p = 0.081). Conclusions There is no statistically significant difference in ACLR graft rupture rates when comparing anteromedial and trans-tibial portal technique for femoral tunnel placement. There was a trend towards higher rupture rates in the anteromedial portal group.

Arthroscopically Assisted Anterior Cruciate Ligament Reconstruction Using Bone–Patellar Tendon–Bone Autograft: Challenges and Solutions of Medial Independent Femoral Tunnel Drilling

Background: As the main translational and rotatory stabilizer of the knee, the anterior cruciate ligament (ACL) plays a critical role in knee biomechanics. Anterior cruciate ligament ruptures generally require surgical attention for not only restoration of knee stability but also prevention of meniscal and chondral injuries. There are countless options for both the surgeon and the patient when contemplating graft choice and surgical technique for ACL reconstruction. However, the literature assessing the outcomes following various autografts has varied with some studies citing no significant difference in clinical and patient-reported outcomes, while others showing notable advantage when using bone–patellar tendon–bone (BPTB) autograft. In addition, there have been challenges associated with femoral tunnel placement using an anteromedial portal technique. Indications: In this study, we present a young female patient with a history of remote mid-substance ACL tear now presenting with worsening knee instability and a bucket-handle medial meniscus tear as a sequela of the incompetent ACL. After extensive discussion regarding the treatment options, patient had decided to proceed with surgical intervention with a BPTB autograft using the anteromedial portal technique for femoral tunnel placement and compression technique with bio-absorbable interference screw fixation. Results: Bone–patellar tendon–bone autograft has been noted to have lower risk of revision when compared with other graft options. Discussion: In this surgical technique study, we underline the importance of peritenon handling. We highlight the use of a 70-degree arthroscope to improve posterolateral wall visualization during femoral tunnel placement as well as for inspection of the reamed tibial tunnel. We also provide technique commentary and solutions for management of the medial femoral condyle (MFC) articular surface and femoral tunnel placement using an anteromedial portal technique. Last, we review graft-related outcomes, postoperative management, and rehabilitation protocol.

Femoral Tunnel Placement Analysis in ACL Reconstruction Through Use of a Novel 3-Dimensional Reference With Biplanar Stereoradiographic Imaging

Background: The femoral-sided anatomic footprint of the anterior cruciate ligament (ACL) has been widely studied during the past decades. Nonanatomic placement is an important cause of ACL reconstruction (ACLR) failure. Purpose: To describe femoral tunnel placement in ACLR through use of a comprehensive 3-dimensional (3D) cylindrical coordinate system combining both the traditional clockface technique and the quadrant method. Our objective was to validate this technique and evaluate its reproducibility. Study Design: Descriptive laboratory study. Methods: The EOS Imaging System was used to make 3D models of the knee for 37 patients who had undergone ACLR. We designed an automated cylindrical reference software program individualized to the distal femoral morphology of each patient. Cylinder parameters were collected from 2 observers’ series of 3D models. Each independent observer also manually measured the corresponding parameters using a lateral view of the 3D contours and a 2-dimensional stereoradiographic image for the corresponding patient. Results: The average cylinder produced from the first observer’s EOS 3D models had a 30.0° orientation (95% CI, 28.4°-31.5°), 40.4 mm length (95% CI, 39.3-41.4 mm), and 19.3 mm diameter (95% CI, 18.6-20.0 mm). For the second observer, these measurements were 29.7° (95% CI, 28.1°-31.3°), 40.7 mm (95% CI, 39.7-41.8 mm), and 19.7 mm (95% CI, 18.8-20.6 mm), respectively. Our method showed moderate intertest intraclass correlation among all 3 measuring techniques for both length ( r = 0.68) and diameter ( r = 0.63) but poor correlation for orientation ( r = 0.44). In terms of interobserver reproducibility of the automated EOS 3D method, similar results were obtained: moderate to excellent correlations for length ( r = 0.95; P < .001) and diameter ( r = 0.66; P < .001) but poor correlation for orientation ( r = 0.29; P < .08). With this reference system, we were able to describe the placement of each individual femoral tunnel aperture, averaging a difference of less than 10 mm from the historical anatomic description by Bernard et al. Conclusion: This novel 3D cylindrical coordinate system using biplanar, stereoradiographic, low-irradiation imaging showed a precision comparable with standard manual measurements for ACLR femoral tunnel placement. Our results also suggest that automated cylinders issued from EOS 3D models show adequate accuracy and reproducibility. Clinical Relevance: This technique will open multiple possibilities in ACLR femoral tunnel placement in terms of preoperative planning, postoperative feedback, and even intraoperative guidance with augmented reality.

Radiographic Landmarks for Femoral Tunnel Positioning in Lateral Extra-articular Tenodesis Procedures

Background: Lateral extra-articular tenodesis (LET) is being increasingly performed as an additional procedure in both primary and revision anterior cruciate ligament reconstruction in patients with excessive anterolateral rotatory instability. Consistent guidelines for femoral tunnel placement would aid in intraoperative reproducible graft placement and postoperative evaluation of LET procedures. Purpose: To determine radiographic landmarks of a recently described isometric femoral attachment area in LET procedures with reference to consistent radiographic reference lines. Study Design: Descriptive laboratory study. Methods: Ten fresh-frozen cadaveric knees were dissected. The footprints of the lateral femoral epicondyle (LFE) apex and the deep aspects of the iliotibial tract, with its Kaplan fiber attachments (KFAs) on the distal femur, were marked with a 2.5-mm steel ball. True lateral radiographic images were taken. Mean absolute LFE and KFA distances were measured from the posterior cortex line (anterior-posterior direction) and from the perpendicular line intersecting the contact of the posterior femoral condyle (proximal-distal direction), respectively. Furthermore, positions were measured relative to the femur width. Finally, radiographic descriptions of an isometric femoral attachment area were developed. Results: The mean LFE and KFA positions were found to be 4 ± 4 mm posterior and 4 ± 3 mm anterior to the posterior cortex line, and 6 ± 4 mm distal and 20 ± 5 mm proximal to the perpendicular line intersecting the posterior femoral condyle, respectively. The mean LFE and KFA locations, relative to the femur width, were found at –12% and 11% (anterior-posterior) and –17% and 59% (proximal-distal), respectively. Femoral tunnel placement on or posterior to the femoral cortex line and proximal to the posterior femoral condyle within a 10-mm distance ensures that the tunnel remains safely located in the isometric zone. Conclusion: Radiographic landmarks for an isometric femoral tunnel placement in LET procedures were described. Clinical Relevance: These findings may help to intraoperatively guide surgeons for an accurate, reproducible femoral tunnel placement and to reduce the potential risk of tunnel misplacement, as well as to aid in the postoperative evaluation of LET procedures in patients with residual complaints.