Anterolateral ligament anatomy: a comparative anatomical study.

PURPOSE: Some anatomical studies have indicated that the anterolateral ligament (ALL) of the knee is distinct ligamentous structure in humans. The purpose of this study is to compare the lateral anatomy of the knee among human and various animal specimens. METHODS: Fifty-eight fresh-frozen knee specimens, from 24 different animal species, were used for this anatomical study. The same researchers dissected all the specimens in this study, and dissections were performed in a careful and standardized manner. RESULTS: An ALL was not found in any of the 58 knees dissected. Another interesting finding in this study is that some primate species (the prosimians: the red and black and white lemurs) have two LCLs. CONCLUSION: The clinical relevance of this study is the lack of isolation of the ALL as a unique structure in animal species. Therefore, precaution is recommended before assessing the need for surgery to reconstruct the ALL as a singular ligament.

Use of transtibial aimer via the accessory anteromedial portal to identify the center of the ACL footprint.

PURPOSE: To assess the ability of a transtibial aimer with a 7-mm off-set in a standardized position to reach the center of the ACL footprint on the femur through the AM portal. METHODS: Nineteen cadaveric knees were dissected, and the perimeter of the femoral ACL footprint was marked. The aimer was placed just superior to the medial joint line close to the medial condyle through the AM portal. The guide was rested upon the posterior cortex and placed in three different positions: (A) at zero degrees in frontal plane and 60° in axial plane, (B) at 45° in frontal and 45° in axial, and (C) at the center of the ACL insertion site under direct visualization. A digital camera was used to take pictures on the axial plane, and Image J software was used for angle measurement. Aluminum beads were used to mark the three positions indicated by the aimer, and CT scans were performed. The distances from the true center of the ACL to each point were determined. RESULTS: Position A resulted in femoral tunnel placement furthest from the center of the ACL footprint (8.6 mm). Position B was at a distance of 3.2 mm, and position C was the most accurate, with an average distance of 2.0 mm. The angles required by Position C varied with an average of 54° ± 11° in the frontal plane and an average of 44° ± 6° in the axial plane. CONCLUSION: The 7-mm transtibial aimer was unable to reach the center of ACL footprint at a fixed orientation.

Anterior cruciate ligament tunnel position measurement reliability on 3-dimensional reconstructed computed tomography.

PURPOSE: The purpose of this study was to evaluate intraobserver and interobserver reliability of anterior cruciate ligament tunnel location measurement by use of 3-dimensional reconstructed computed tomography (CT). METHODS: Three-dimensional reconstructed CT images of 31 cadaveric knees were used in this study. Twenty-one knees were operated on with a double-bundle technique, and ten knees were operated on with a single-bundle technique. Femoral tunnel location was measured with 3 methods on the medial-lateral view of the lateral femoral condyle in the strictly lateral position. Tibial tunnel location was measured in the top view of the proximal tibia. The images were evaluated independently by 2 orthopaedic surgeons. A second measurement was performed, by both testers, after a 4-week interval. RESULTS: The 3 methods of femoral tunnel location measurement had intraobserver intraclass correlation coefficients (ICCs) that ranged from 0.963 to 0.998 and interobserver ICCs that ranged from 0.993 to 0.999. Tibial tunnel measurement had intraobserver ICCs that varied between 0.957 and 0.998 and interobserver ICCs that varied between 0.993 and 0.996. CONCLUSIONS: The measurement of the anterior cruciate ligament tunnel location on 3-dimensional reconstructed CT provided excellent intraobserver and interobserver reliability. CLINICAL RELEVANCE: Three-dimensional reconstructed CT can be used for further studies to assess the effect of tunnel position on knee stability and patient outcomes.

Correlation between the 2-dimensional notch width and the 3-dimensional notch volume: a cadaveric study.

PURPOSE: The purpose of this study was to compare the size of the entrance of the notch, as measured arthroscopically (2-dimensionally), with the volume of the notch as measured by use of computed tomography (CT) (3-dimensionally). METHODS: For 20 cadaveric knees, the dimensions of the notch entrance were measured arthroscopically, and the notch volume was measured by use of CT. The correlation between the size of the notch entrance and the notch volume was calculated. Intraobserver reliability and interobserver reliability of the arthroscopic and CT measurements were tested. RESULTS: The Pearson correlation coefficients between CT-assessed notch volume and arthroscopically assessed notch height and width at the bottom, middle, and top of the notch were 0.603, 0.506, 0.551, and 0.642, respectively. The intraobserver reliability and interobserver reliability of the arthroscopic measurements were above 0.962 and 0.819, respectively, and 0.983 and 0.975, respectively, for the CT measurements. CONCLUSIONS: There were only moderate correlations between arthroscopic notch measurements and notch volume. Both the arthroscopic and CT measurements proved highly reliable. CLINICAL RELEVANCE: The moderate correlation between 2-dimensional and 3-dimensional notch measurements warrants caution concerning the use of either measurement for assessing risk for anterior cruciate ligament injury or as justification for notchplasty until studies between the relation of 3-dimensional notch volume and anterior cruciate ligament injury are conducted.

A biomechanical comparison of 2 femoral fixation techniques for anterior cruciate ligament reconstruction in skeletally immature patients: over-the-top fixation versus transphyseal technique.

PURPOSE: The purpose of this study was to compare knee kinematics and in situ forces of the graft between 2 femoral fixation techniques of anterior cruciate ligament (ACL) reconstruction: the over-the-top (OTT) fixation and transphyseal (TP) techniques. METHODS: ACL reconstruction in skeletally immature patients is a challenging procedure. Regarding the femoral fixation techniques, 2 methods are commonly used: the OTT fixation and TP techniques. Ten cadaveric knees (mean age, 57 years; range, 48 to 65 years) were tested with the robotic/universal force-moment sensor system by use of (1) an 89-N anterior tibial load at full extension and 15°, 30°, 60°, and 90° of knee flexion and (2) a combined 7-Nm valgus torque and 5-Nm internal tibial rotation torque at 15° and 30° of knee flexion. RESULTS: Both OTT and TP ACL reconstruction techniques closely restored the intact knee kinematics and had a significant reduction in anterior tibial translation under an anterior tibial load and in coupled anterior tibial translation under a combined rotatory load when compared with an ACL-deficient knee. When both ACL reconstruction techniques were compared, the only difference found was that the in situ force of the ACL graft reconstructed with the OTT technique in response to a combined rotatory load at 30° of flexion was significantly lower than the ACL graft reconstructed with the TP technique (5.3 ± 3.3 N and 10.7 ± 6.0 N, respectively; P = .013). CONCLUSIONS: This time 0 testing showed that both ACL reconstruction techniques, OTT and TP, can reproduce the kinematics of the intact knee in response to an anterior tibial load and a combined rotatory load. CLINICAL RELEVANCE: Both femoral fixation techniques exhibited comparable time 0 kinematics when subjected to simulated clinical examination loading conditions.

Does the Anchor Eye Alignment Affect the Performance of the Rotator Cuff Repair? A Biomechanical Study.

PURPOSE: To investigate the metal screw-in anchor failure mode and load to failure for 2 different eyelet alignments after anchor insertion in ovine humeri. METHODS: Sixteen ovine humeri were dissected, and a 5-mm metal anchor with 2 nonabsorbable polyblend polyethylene sutures was inserted into them in the proximal position of the greater tuberosity. The alignment of the anchors after insertion was adjusted to make 2 test groups, each with 8 specimens: In group 1, the anchor eyelets were malpositioned, whereas in group 2, the anchor eyelets were aligned according to the manufacturer's instructions. After insertion, cyclic tests from 10 N to 180 N were performed with a frequency of 1 Hz for 200 cycles; specimens were then loaded to failure to evaluate the maximum load of the system and observe the associated failure mode. RESULTS: The mean ultimate failure load in group 2 was not significantly different from that in group 1 (P = .472). CONCLUSIONS: For metallic screw-in suture anchors, the alignment of the eyelet does not change the failure mode and the load to failure after cyclic loading of the bone-anchor-suture system in ovine humeri. CLINICAL RELEVANCE: Our results indicate that on the basis of this anchor model, the position of the eyelet in the greater tuberosity does not interfere directly with the biomechanical performance of the system.

Femoral intercondylar notch shape and dimensions in ACL-injured patients.

The femoral intercondylar notch has been an anatomic site of interest as it houses the anterior cruciate ligament (ACL). The objective of this study was to arthroscopically evaluate the femoral notch in patients with known ACL injury. This evaluation included establishing a classification for notch shapes, identifying the shape frequency, measuring notch dimensions, and determining correlation between notch shape, notch dimensions, and demographic patient data. In this clinical cohort study, 102 consecutive patients underwent diagnostic arthroscopic evaluation of the notch. Several intra-operative photos, videos, and measurements were taken of the notch. Demographic data for each patient were recorded including age, gender, height, weight, and BMI. Three categories of notch shape were established: 1. A-shaped; 2. U-shaped; and 3. W-shaped. Two blinded independent orthopedic surgeons were asked to categorize the recorded notches. Notch shape, dimensions, and demographic factors were correlated. Of the 102 notches evaluated, 55 notches were found to be "A-shaped," 42 "U-shaped," and 5 "W-shaped." "A-shaped" notches were narrower in all width dimensions than "U-shaped" notches. Only patient height was found to influence notch shape with a positive association between taller patients and "U-shaped" and "W-shaped" notches (P = 0.011). Women had a smaller notch width at the base and middle of the notch. With this data, surgeons who enter the knee and appreciate an "A-shaped" notch should consider placing the arthroscope in the anteromedial portal and drill the femoral tunnel through an accessory medial portal to improve visualization and accuracy in anatomic femoral tunnel creation.

Assessment of correlation between knee notch width index and the three-dimensional notch volume.

This study was done to determine whether there is a correlation between the notch volume and the notch width index (NWI) as measured on the three most frequently used radiographic views: the Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg view. The notch volume of 20 cadaveric knees was measured using Computed Tomography (CT). The Holmblad 45 degrees, Holmblad 70 degrees, and Rosenberg notch view radiographs were digitally re-created from the CT scans for each specimen, and the NWI was measured by two observers. The Pearson correlation coefficient between the NWI and notch volume was calculated, as well as between the three views. An independent t test was performed to determine the difference in NWI and notch volume between male and female specimens. The reliability for each view was also determined. There was no correlation between the NWI as measured on the Holmblad 45 degrees, Holmblad 70 degrees, or Rosenberg view and the notch volume. All three radiographic views proved reliable, but showed only a moderate correlation with each other. Men had larger notch volumes than women, but there was no difference in NWI. A knee with a small intercondylar notch is often considered an increased risk for ACL rupture. The NWI is a frequently used two-dimensional method to determine notch size. However, in the present study, this index was not positively correlated with the overall volume of the notch. Based on the results of the current study, the authors would advice to use caution when using notch view radiographs in a clinical setting to predict risk of ACL rupture.

Contribution of the meniscofemoral ligament as a restraint to the posterior tibial translation in a porcine knee.

The meniscofemoral ligament (MFL) is a major structure in the posterior aspect of the porcine knee together with the posterior cruciate ligament (PCL). While the porcine knee is a frequently used animal model for biomechanical evaluation of PCL reconstruction techniques, the contribution of the MFL to stability of the porcine knee is not well understood. The purpose of this study is (1) to evaluate the kinematics of the knee after sequential cutting of the PCL and MFL and (2) to determine the in situ forces of the PCL and MFL in response to a posterior tibial load of 89 N using the robotic/universal force-moment sensor system from 15 degrees to 90 degrees of knee flexion. Ten porcine knees were used in this study. The magnitude of posterior tibial translation under a posterior tibial load was significantly increased (P < 0.01) after sequential transection of the PCL and the MFL at each testing angle compared to the intact condition. The in situ force of the PCL was highest at 60 degrees of flexion (82.3 +/- 8.6 N) and lowest at 15 degrees of flexion (45.1 +/- 15.9 N). The in situ force of the MFL was highest at 15 degrees of flexion (24.3 +/- 6.5 N) and lowest at 90 degrees of flexion (12.9 +/- 10.5 N). The findings in this study revealed a biomechanical contribution of the MFL as the secondary restraint to the posterior tibial translation in conjunction with the PCL especially near full extension.

The location of femoral and tibial tunnels in anatomic double-bundle anterior cruciate ligament reconstruction analyzed by three-dimensional computed tomography models.

BACKGROUND: Characterization of the insertion site anatomy in anterior cruciate ligament reconstruction has recently received increased attention in the literature, coinciding with a growing interest in anatomic reconstruction. The purpose of this study was to visualize and quantify the position of anatomic anteromedial and posterolateral bone tunnels in anterior cruciate ligament reconstruction with use of novel methods applied to three-dimensional computed tomographic reconstruction images. METHODS: Careful arthroscopic dissection and anatomic double-bundle anterior cruciate ligament tunnel drilling were performed with use of topographical landmarks in eight cadaver knees. Computed tomography scans were performed on each knee, and three-dimensional models were created and aligned into an anatomic coordinate system. Tibial tunnel aperture centers were measured in the anterior-to-posterior and medial-to-lateral directions on the tibial plateau. The femoral tunnel aperture centers were measured in anatomic posterior-to-anterior and proximal-to-distal directions and with the quadrant method (relative to the femoral notch). RESULTS: The centers of the tunnel apertures for the anteromedial and posterolateral tunnels were located at a mean (and standard deviation) of 25% +/- 2.8% and 46.4% +/- 3.7%, respectively, of the anterior-to-posterior tibial plateau depth and at a mean of 50.5% +/- 4.2% and 52.4% +/- 2.5% of the medial-to-lateral tibial plateau width. On the medial wall of the lateral femoral condyle in the anatomic posterior-to-anterior direction, the anteromedial and posterolateral tunnels were located at 23.1% +/- 6.1% and 15.3% +/- 4.8%, respectively. The proximal-to-distal locations were at 28.2% +/- 5.4% and 58.1 +/- 7.1%, respectively. With the quadrant method, anteromedial and posterolateral tunnels were measured at 21.7% +/- 2.5% and 35.1% +/- 3.5%, respectively, from the proximal condylar surface (parallel to the Blumensaat line), and at 33.2% +/- 5.6% and 55.3% +/- 5.3% from the notch roof (perpendicular to the Blumensaat line). Intraobserver and interobserver reliability was high, with small standard errors of measurement. CONCLUSIONS: This cadaver study provides reference data against which tunnel position in anterior cruciate ligament reconstruction can be compared in future clinical trials.

Topography of the femoral attachment of the posterior cruciate ligament. Surgical technique.

BACKGROUND: The success of posterior cruciate ligament reconstruction has varied. The objective of this study was to determine quantitatively and qualitatively the topography and osseous landmarks of the femoral footprints of the anterolateral and posteromedial bundles of the posterior cruciate ligament, to improve surgical reconstruction. METHODS: Twenty unpaired knees from twenty human cadavers were evaluated. The surface features of the femoral footprints of the anterolateral and posteromedial bundles of the posterior cruciate ligament were studied by means of macroscopic observation and three-dimensional laser photography. RESULTS: We observed, both visually and with three-dimensional laser photography, an osseous prominence located proximal to the femoral footprint of the posterior cruciate ligament in eighteen of the twenty human knees. This osseous landmark, denominated the "medial intercondylar ridge," determined the proximal border of the posterior cruciate ligament footprint. In eight of the twenty knees, we observed a small osseous prominence between the anterolateral and posteromedial bundles of the posterior cruciate ligament. A clear change in the slope of the femoral footprint of the posterior cruciate ligament was observed between the anterolateral and posteromedial bundles. The average area of the posterior cruciate ligament footprint (and standard deviation) was 209 +/- 33.82 mm2, the average area of the anterolateral bundle was 118 +/- 23.95 mm2, and the average area of the posteromedial bundle was 90 +/- 16.13 mm2. CONCLUSIONS: The femoral footprint of the posterior cruciate ligament has a unique surface anatomy, consisting of a medial intercondylar ridge and a medial bifurcate ridge. The medial intercondylar ridge is observed more frequently.

O conceito da reconstrução anatômica do LCA dupla banda / The concept of anatomic anterior cruciate ligament reconstruction

Um interesse cada vez maior na reconstrução dupla banda do LCA tem estimulado um grande avanço nesta área de pesquisa e levado a um aumento no nosso conhecimento de anatomia, cinemática e função do joelho. Estudos recentes têm melhor definido o tamanho e orientação das inserções femorais e tibiais das bandas ântero-medial e póstero-lateral do LCA. O objetivo da reconstrução anatômica do LCA é utilizar esses novos conceitos para melhorar a técnica cirúrgica e mimetizar a anatomia original do LCA. Acreditamos que a reconstrução anatômica do LCA irá resultar em uma melhora na biomecânica e, consequentemente, uma melhora no quadro funcional de cada paciente.

Estudo biomecânico da subida de degraus de grandes alturas / Study biomecanic of the ascending stairs

People are all lhe time looking for ways to improve their daily lives, but lhey create shorter pathways calied shortcuts to reach the desired destination. Very high steps are an example of this situation present in our daily lives, like stairs in lhe regular walking pathway. People do not usually realize all lhe musculoskeletal problems involved in these situations. The purpose of this study is the step ascent movement analysis with cinematographic — SPICA DMAS for the kinematics acquisition, dynamometric using two force platforms devices and anthropometrics data analyzing the temporal, magnitude, and knee flexion angle aspects related to the ground reaction force. In this study different step heights, 20 cm, 40 cm and 60 cm were used, found in daily life pathways and regular walking situations. Sixteen physically active people ranging in height from 1.55 m to 1.86 m participated as subjects. A self-controlled speed (average 3.95 km/h) in the step ascent was performed for all subjects. The maximum peak of ground reaction force, impact, stance and swing time, the double landing step and knee fexion angle were analyzed. In the second peak increased force was verified when the subject was ascending the step. Ninety degrees of knee flexion angle and over for lhe 40cm step and 60 cm step were regislered, characterizing high compressive forces around the knee joint. Step dimensions, therefore, influenced the kinematics of the lower limb during this study. The authors can conclude that high step are a challenge for people in their daily lives and this can expose the musculoskeletal system to injuries due to the compressive force around the lower limb joints