Variances of the intraarticular landmarks for anterior cruciate ligament tibial footprint: Tibial eminencies have less variability than lateral meniscus on sagittal magnetic resonance scans

Objective: The purpose of this study was to analyze the sagittal plane variations of intraarticular landmarks for single bundle anterior cruciate ligament (ACL) reconstruction including lateral meniscus, medial and lateral tibial eminencies. Methods: T2 weighted sagittal magnetic resonance (MR) scans of 80 skeletally mature patients aged between 18 to 60 years and without any sign of ligament and meniscal injuries were viewed. Midpoint of ACL, most posterior aspect of anterior horn of lateral meniscus (LMAH), tip of medial eminence (ME) and lateral eminence (LE) were identified on widest antero-posterior (A-P) distance of tibial plateau according to of Staubli-Rausching method and variances were compared. Results: Mean location of center of tibial footprint of ACL at sagittal plane was found as 38.0±4.2% (range, 29-51%) on A-P distance of tibial plateau. Location of posterior border of LMAH, ME and LE were 38.0±12.4% (range, 21-62%), 52.3±4.2% (range, 41- 60%) and 59.5±4.4% (range, 51- 69%), respectively. Difference between the variances of ACL midpoint and LMAH was large enough to be statistically significant (p=<.001) with a large effect size (f=0.59), however differences between the variances of ACL midpoint and bony landmarks were not significant (ME, p=.65; LE, p=.33). Intra and interobserver agreement for measurement of all parameters were detected as moderate to good. Conclusion: There was no constant relationship between ACL midpoint and posterior border of LMAH on sagittal plane MR images. Difference of variances between ACL midpoint and ME and LE were significantly lower than of variances of LMAH.

Biomechanical Analysis of Ideal Knee Flexion Angle for ACL Graft Tensioning Utilizing Multiple Femoral and Tibial Tunnel Locations

Anterior cruciate ligament (ACL) graft failure rate has been reported to be greater than 5% at 5 years. Our study evaluated ACL excursion with anatomic and nonanatomic femoral and tibial tunnels to determine optimal flexion angle to tension the ACL to minimize excursion. Ten cadaveric knee specimens were used. The ACL was sectioned and the femoral and tibial attachments were marked. A 1/16-inch drill created a tunnel in the center of the ACL footprint on the tibia and femur and additional tunnels were made 5 mm from this. A suture was passed through each tunnel combination and attached to a string potentiometer. The knee was ranged from full extension to 120 degrees of flexion for 10 cycles while mounted in a custom fixture. The change in length (excursion) of the suture during movement was recorded for each combination of femoral and tibial tunnels. Anatomic reconstruction of the ACL with tunnel placement in the center of the femoral and tibial footprint did not result in an isometric graft, with excursion of the ACL during knee motion of 7.46 mm (standard deviation [SD]: 2.7mm), greatest at 2.84 degrees of flexion (SD: 4.22). The tunnel combination that resulted in the least excursion was a femoral footprint 5 mm anterior to the femoral and 5 mm posterior to the tibial footprint (4. 2mm, SD: 1.37 mm). The tunnel combination that resulted in the most excursion utilized femoral footprint 5 mm proximal to the femoral and 5 mm posterior to the tibial footprint (9.81 mm, SD: 2.68 mm). Anatomic ACL reconstruction results in significant excursion of the ACL throughout motion. If not tensioned properly, the ACL can stretch during range of motion, potentially leading to rerupture. To prevent stretching of the graft, the current biomechanical study recommends tensioning an anatomic ACL reconstruction at its point of maximal excursion, or between 0 and 5 degrees of flexion. Level of Evidence IV

Relation of arthroscopic measurement of tibial footprint with the height, weight, or gender of patients: A pilot study on Indian subject

Objectives: A prospective study performed to evaluate whether any correlation exists between tibial footprint size (length and width) of anterior cruciate ligament (ACL) with the height, weight, or gender of patients. Materials and Methods: A total of 53 patients presenting with an ACL tear (54 knees) in 8 months duration who underwent ACL reconstruction were evaluated for height, weight, and gender. Arthroscopic measurement of ACL footprint’s length and width with calibrated probe and measuring scale was done and the average of those measurements was recorded and compared using SPSS software. Results: Out of 53 Patients, 45 were male with a mean age of 28.73 years and a mean height of 66.67 inches. Their mean ACL footprint dimension was 17.40 mm × 7.67 mm2. The remaining eight were female patients with a mean age of 29.2 years and a mean height of 66.17 inches. Their mean ACL footprint dimension was 17.35 mm × 7.61 mm2. Correlation between ACL tibia footprint length versus width was found to be statistically significant. However, the correlation between the patient’s height or weight versus ACL tibial footprint (length and width) was not significant statistically. Conclusion: ACL footprint size cannot be predicted from the height, weight, or gender of patients.

Interrater Agreement of an Arthroscopic Anterior Cruciate Ligament Tear Classification System

Background: Anterior cruciate ligament (ACL) rupture is the most common ligament injury treated surgically by orthopaedic surgeons. The gold standard for the treatment of the majority of primary ACL tears is ACL reconstruction. However, novel methods of repair, such as bridge-enhanced ACL repair (BEAR), are currently being investigated as alternatives to reconstruction. To assess patients for midsubstance repair suitability, clarify the prognostic implications of injury location and damage, and evaluate the results of a repair technique, it is important to have a baseline classification system or grading scale that is reproducible across surgeons, particularly for multicenter collaboration. Currently, no such system or scale exists. Purpose: To develop an arthroscopic ACL tear classification system and to evaluate its interobserver reliability. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Eleven fellowship-trained orthopaedic surgeon investigators reviewed 75 video clips containing arthroscopic evaluation of a torn ACL and then completed the 6-question ACL Pathology Evaluation Form. Agreement statistics including exact agreement, Fleiss κ, Gwet agreement coefficient 1 (AC1), and Gwet AC2 were then calculated to assess interobserver reliability. Results: In aggregate, the multiple assessments of observer reproducibility revealed that surgeon participants in this study, when evaluating the same injury, agreed roughly 80% of the time on whether (1) at least 50% of the tibial footprint remained, (2) the remaining tibial stump was ≥10 mm, and (3) the injury was therefore reparable using the BEAR procedure. Participants also agreed roughly 60% of the time on exactly how many suturable bundles were available. These characteristics are believed to be most important, among those studied, in determining whether a torn ACL is amenable to midsubstance repair. Conclusion: This study is the first of its kind to demonstrate the interobserver reliability of arthroscopic classification of ACL tears. We have demonstrated that this classification system, though not ideally reproducible, is reliable enough across surgeons at multiple institutions for use in multicenter studies. Registration: NCT03776162 ( ClinicalTrials.gov identifier).

Evaluating the Accuracy of Tibial Tunnel Placement After Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

Background: Anatomic anterior cruciate ligament (ACL) reconstruction improves knee kinematics and joint stability in symptomatic patients who have ACL deficiency. Despite a concerted effort to place the graft within the ACL’s native attachment sites, the accuracy of tunnel placement using contemporary techniques is not well established. Purpose: To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate the accuracy of tibial tunnel placement after anatomic ACL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Forty patients with symptomatic, ACL-deficient knees were prospectively enrolled in the study and underwent 3D MRI of both their injured and uninjured knees before and after surgery through use of a validated imaging protocol. The root ligament of the anterior horn of the lateral meniscus was used as a radiographic reference, and the center of the reconstructed graft was compared with that of the contralateral normal knee. The tunnel angles and intra-articular graft angles were also measured, as was the percentage overlap between the native tibial footprint and tibial tunnel. Results: The reconstructed tibial footprint was placed at a mean ± SD of 2.14 ± 2.45 mm ( P < .001) medial and 5.11 ± 3.57 mm ( P < .001) posterior to the native ACL footprint. The mean distance between the center of the native and reconstructed ACL at the tibial attachment site was 6.24 mm. Of the 40 patients, 18 patients had a tibial tunnel that overlapped more than 50% of the native footprint, and 10 patients had maximal (100%) overlap. Further, 22 of the 40 patients had less than 50% overlap with the native footprint, and in 12 patients the footprint was missing completely. Conclusion: Despite the use of contemporary surgical techniques to perform anatomic ACL reconstruction, a significant positioning error in tibial tunnel placement remains.

Different Strategies in Making Transseptal Portal for the Different Purposes

The purpose of this study was to find the most suitable and safe position of the transseptal portal in anatomic anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstructions. The hypothesis of this study was that area and position of the transseptal portal are different between ACL and PCL reconstructions for the observation of native footprint. A matched-pair comparison study was conducted on the arthroscopic images of 100 consecutive patients who underwent ACL reconstruction and 50 consecutive patients who underwent PCL reconstruction. The transseptum was divided into six compartments. The opened compartments for each surgery were then evaluated to find which anatomical structures are well seen. The anterior middle and upper parts were necessary for the ACL reconstruction, whereas middle and lower portions of the anterior and posterior compartments were necessary for the PCL reconstruction. A larger opening was necessary for PCL reconstruction than that for ACL reconstruction. The ACL posterior one-third, ACL femoral attachment, and apex of the deep cartilage margin (DCM) were viewed in 100% of the patients during ACL reconstruction. The PCL posterior one-third, PCL tibial attachment, PCL fovea margin, and medial meniscus around posterior margin were always viewed during PCL reconstruction. The anterior part of the septum, from the middle to the upper portions of the transseptum, was necessary to be opened for visualization of the femoral footprint and DCM of the lateral femoral condyle during ACL reconstruction. The anterior and posterior parts of the septum, from the middle to the lower portions of the transseptum, were necessary for excellent visualization of the PCL tibial footprint during PCL reconstruction. These paths of the transseptal portal for each surgery will help surgeons obtain both anatomic footprint restoration and maximal remnant preservation through the most suitable and safe means. This is a case–control study; level of evidence is 3.