Anterior Cruciate Ligament Insertion Site Research Articles

Anterior Cruciate Ligament Reconstruction: 3-Incision Technique With Allograft Quad Tendon ACL Reconstruction

Background: Anterior cruciate ligament (ACL) ruptures are becoming more common in younger and older athletes. Approximately 250,000 ACL injuries occur each year, requiring the need for an effective and reproducible surgical technique. Indications: The 3-incision outside-in technique utilizes the donor quadriceps tendon, an extraordinarily strong graft, without damage from autogenous harvesting of patellar tendon or hamstrings. While some data suggest higher re-rupture risk with donor tissue, this is counterbalanced by avoiding secondary surgical site damage. Technique Description: The ruptured ACL is removed and the intercondylar notch is cleaned to visualize the anatomical ACL insertion site. Using the 3-tunnel technique a gaff is passed through the intercondylar notch, through a puncture hole (incision 1) and a rear entry guide hooked to its tip. The guide point is pulled into the knee and placed in posterior aspect of the anatomic footprint of the native ACL. Through incision 2, a guide pin is drilled to this point and overdrilled with a 10-mm drill. The edges of the hole in the intercodylar notch are smoothed with a currette. The tibial footprint is cleared, a tibial aiming guide placed. Through incision 3, a guide pin is placed and over drilled with a 10-mm drill followed by a Gore-Tex reamer to ensure no impingement would inhibit graft passage. The proximal bone of a quadriceps tendon graft is sized through a 10-mm sizer and compacted. Two holes are drilled to hold sutures for the proximal aspect of the femoral graft. The quadriceps tendon graft is sized to fit through a 9-mm tunnel and the free end whipped with a stitch before being passed from outside-in through the smoothed tunnels. The femoral bone block is tapped to have a press fit initially and then is fixed with a Milagro screw. The knee is cycled ten times to remove slack and the interference fit guide pin is placed on the anterior aspect of the graft, and fixed with the knee at 15° to 30° of flexion. Stability is tested with confirmation of no impingement, and then an extra-articular reconstruction with a semitendinosus allograft is performed. The extra articular reconstruction is placed at the point between Gerdy's tubercle and the fibular head, passed under the skin and the iliotibial band, and then inserted just anterior and superior to the ACL femoral drill hole. Results: Patient outcomes in our initial experience are comparable to our autogenous bone-tendon-bone (BTB) procedures without anterior knee pain. Return to sport is similar with autogenous procedures, with a delay of 6 to 12 months. In addition, there is a possibility for acceleration of healing with the addition of platelet-rich plasma and hyaluronic acid between 1 and 3 months postsurgery. We have insufficient data so far to determine if the re-rupture rate will decline compared with reported outcomes. Conclusion: The 3-incision technique with allograft quadriceps tendon for ACL reconstruction is a reproducible surgical technique that avoids harvest from the patient's own body. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

ACL Graft Matching: Cadaveric Comparison of Microscopic Anatomy of Quadriceps and Patellar Tendon Grafts and the Femoral ACL Insertion Site

Background: The optimal graft choice between the bone–patellar tendon–bone (BPTB) and the quadriceps tendon remains controversial. Studies evaluating the microscopic anatomy of the quadriceps tendon–patellar bone (QTB) and BPTB grafts for anterior cruciate ligament (ACL) reconstruction are currently lacking. Hypothesis: The relationship between post–ACL reconstruction graft bending angle (GBA) and the angle corresponding to the GBA (cGBA) would indicate that the BPTB can bend more than the QTB at the femoral tunnel aperture. Study Design: Controlled laboratory study. Methods: Twenty paired human cadaveric knees fixed at <10° of knee joint flexion (mean age, 82.5 years) underwent histological sectioning and staining with Masson trichrome and toluidine blue. The femoral ACL insertion, QTB graft, and BPTB graft were microscopically analyzed. The width of the direct insertion, thickness of the uncalcified fibrocartilage and calcified fibrocartilage, ligament attachment angle, and cGBA for each group were measured. Eighteen patients who underwent ACL reconstruction with QTB or BPTB autograft were included for the evaluation of GBA using computed tomography images at 1 week postoperatively. Results: The mean insertion widths of the femoral ACL, QTB, and BPTB were 7.81, 9.07, and 6.54 mm, respectively. The QTB was 16% wider than the ACL, while the BPTB was 16% narrower than the ACL. The mean insertion thicknesses of the femoral ACL, QTB, and BPTB were 0.53, 0.94, and 0.38 mm, respectively. The QTB was 77% thicker than the ACL (P < .001), while the BPTB was 28% thinner than the ACL (P = .017). The mean ligament attachment angles of the femoral ACL, QTB, and BPTB were 20.3°, 30.2°, and 33.3°, respectively, and the QTB and the BPTB were 49% and 64% larger, respectively, than the ACL. The mean cGBAs of the femoral ACL, QTB, and BPTB were 33.9°, 35.1°, and 12.3°, respectively. The BPTB was 64% smaller than the ACL, while there was no significant difference between the QTB and the ACL. The mean GBA was 57.7°. Conclusion: The insertion width and thickness were significantly greater and smaller in the QTB and BPTB grafts, respectively, than in the ACL. The relationship between GBA after ACL reconstruction and cGBA in knee extension indicates that at the femoral tunnel aperture, the BPTB can bend more than the QTB. Clinical Relevance: QTB graft may allow more anatomic ACL reconstruction to be performed.

Arthroscopic anatomy and pathoanatomy of anterior cruciate ligament ruptures: clinical study with 94 patients

Purpose: To arthroscopically evaluate the size variability of the Anterior cruciate ligament (ACL) insertion sites and to determine whether there are variations in rupture patterns of the two ACL bundles.&#x0D; Material and Methods: Ninetyfour patients undergoing ACL reconstruction between June 2008 and June 2009 were included inour study. The average age of the patients was 26.7 ± 8.3 years (range, 16–48 years). Only patients with an ACL rupture less than 120 days old were included as unpublished data revealed difficulty in distinguishing between AM and PL bundles in older ACL ruptures.&#x0D; Results: The femoral ACL insertion site length ranged from 11 to 20 mm (15.9 ± 2.2). On the tibial side, the length of the tibial ACL insertion site ranged from 9 to 20 mm (16.0 ± 2.1). On the femoral side, the width of the ACL insertion site ranged from 6 to 11 mm (8.3 ± 1.2). On the tibial side, the width of the entire ACL insertion site ranged from 6 to 12 mm (8.7 ± 1.1). The most frequent injury pattern was found to be the proximal rupture of both bundles; seen in 74 patients (78.7%).&#x0D; Conclusion: Both hypotheses were confirmed, and this may be clinically relevant in anatomic ACL reconstruction.

Effect of Percentage of Femoral Anterior Cruciate Ligament Insertion Site Reconstructed With Hamstring Tendon on Knee Kinematics and Graft Force

Background: Previous studies have stated that closely matching the size of the anterior cruciate ligament (ACL) insertion site footprint is important for biomechanical function and clinical stability after ACL reconstruction. However, the ACL varies widely regarding the area of femoral insertion, tibial insertion, and midsubstance of ACL, and reconstructing the insertion site area with a uniform diameter graft can result in a cross-sectional area that is greater than that of the midsubstance of the native ACL. Therefore, understanding the effect of relative graft size in ACL reconstruction on knee biomechanics is important for surgical planning. Purpose: To assess how the percentage of femoral insertion site affects knee biomechanics in single- and double-bundle ACL reconstruction. Study Design: Controlled laboratory study. Methods: A total of 14 human cadaveric knees were scanned with magnetic resonance imaging and tested using a robotic system under an anterior tibial load and a combined rotational load. In total, 7 knee states were evaluated: intact ACL; deficient ACL; single-bundle ACL reconstruction with approximate graft sizes 25% (small), 50% (medium), and 75% (large) of the femoral insertion site; and double-bundle reconstruction of approximately 50% (medium) and 75% (large) of the femoral insertion site, based on the ratio of the cross-sectional area of the graft to the area of the femoral ACL insertion site determined by magnetic resonance imaging. Results: Anterior tibial translation was not significantly larger than the intact state in single-bundle and double-bundle medium graft reconstructions (P > .05) and was significantly greater in the single-bundle small graft reconstruction (P < .05). Anterior knee translation in single-bundle medium graft and large graft reconstructions was not statistically different (P > .05). In contrast, the anterior tibial translation for double-bundle large graft reconstruction was significantly smaller than for double-bundle medium graft reconstruction at low flexion angles (P < .05). The single-bundle small graft force was significantly different from the intact ACL in situ force (P < .05). The graft force with double-bundle large reconstruction was significantly greater than that with the double-bundle medium reconstruction (P < .05) but was not significantly different from that of the intact ACL (P > .05). Conclusion: Knee biomechanics with a single-bundle small graft tended to be significantly different from those of the intact knee. In the kinematic and kinetic data for the single- and double-bundle medium graft reconstruction, only the anterior translation at full extension for the single-bundle reconstruction was significantly different (lower) from that of intact knee. This was a time zero study. Clinical Relevance: This study can provide surgeons with guidance in selecting the graft size for ACL reconstruction.

Gender Differences of the ACL Insertion Sites

Background. The modern principles of reconstruction of the anterior cruciate ligament (ACL) and well-known surgical techniques do not take into account the peculiarities of the anatomical structure of the female knee. This happens due to insufficient substantiation that these peculiarities could influence the results of the treatment. The purpose of this study was to obtain new data on the structure of the areas of the ACL attachment, taking into consideration patient’s gender and the surgical anatomy. Material and Methods. 40 unpaired “fresh” anatomical preparations of the human female and male knees were studied. After preparation of the knee joints, the morphometry of the distal femoral epiphysis and the proximal tibial epiphysis was carried out by a digital sliding caliper according to 16 parameters. The shape, size, area, and the distance of the ACL attachment center from individual bone structures were assessed. The obtained data were correlated with the gender type of the knee structure. Results. The distal femoral epiphysis of the “female” type knee joint compared with the “male” type revealed the significant differences (p0.05) in the following parameters: the width of the condyles at the level of the transepicondylar line, the width of the intercondylar fossa, the length and height of the lateral condyle, and the ratio of the condyles width at the level of the transepicondylar line to the height of the lateral condyle. The tibial proximal epiphysis showed the gender differences in the articular surface frontal and sagittal dimensions, the width of the intercondylar eminence and the posterior slope of the tibial epiphysis articular surface. These features determined the different proportions of the female knee structure. The area of the anterior cruciate ligament femoral attachment and its center in the “female” type of structure were located 3 mm distal and 1.5 mm posteriorly (anteriorly and downwardly in arthroscopic imaging). The area of the tibial attachment of the same ligament and its center were localized 2 mm anteriorly in comparison with the “male” type structure. Conclusion. The discovered anatomical differences made it possible to distinguish the “female” and “male” types of the knee structure. The topography of the anterior cruciate ligament attachment areas is gender specific. This should be taken into account in the anatomical reconstruction of the ligament.

Anterior Cruciate Ligament Reconstruction Using a Ribbon-Like Graft With a C-Shaped Tibial Bone Tunnel

According to recent anatomic studies, the anterior cruciate ligament (ACL) appears to be a flat, “ribbon-like” structure, with a thin, oval-shaped insertion on the femur and a C-shaped tibial insertion. According to this anatomy, we describe an ACL-reconstruction technique that aims to approximate this natural anatomy. The basic principle of this technique is not to use conventional round tunnels but create tunnel shapes that resemble more closely the original ACL insertion sites. Using either a rectangular quadriceps tendon graft or a “flat” hamstring graft may not only provide a biomechanical advantage with increased rotational stability but also improve bone–tendon healing due to increased bone–tendon contact and decreased diffusion length. Creating a C-shaped tibial tunnel also avoids laceration of the anterior horn of the lateral meniscus, which is frequently harmed during conventional tibial tunnel drilling.

Measurement of the Whole and Midsubstance Femoral Insertion of the Anterior Cruciate Ligament: The Comparison with the Elliptically Calculated Femoral Anterior Cruciate Ligament Footprint Area.

Purpose:The purpose of this study was to measure the detailed morphology of the femoral anterior cruciate ligament (ACL) footprint. The correlation and the comparison between the measured area and the area which mathematically calculated as elliptical were also evaluated.Materials and Methods:Thirty nine nonpaired human cadaver knees were used. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the whole footprint and the midsubstance insertion. Lateral view of the femoral condyle was photographed with a digital camera, and the images were downloaded to a personal computer. The area, length, and width of the femoral ACL footprint were measured with Image J software (National Institution of Health). Using the length and width of the femoral ACL footprint, the elliptical area was calculated as 0.25 π (length × width). Statistical analysis was performed to reveal the correlation and the comparison of the measured and elliptically calculated area.Results:The sizes of the whole and midsubstance femoral ACL footprints were 127.6 ± 41.7 mm2 and 61 ± 20.2 mm2, respectively. The sizes of the elliptically calculated whole and midsubstance femoral ACL footprints were 113.9 ± 4.5 mm2 and 58.4 ± 3 mm2, respectively. Significant difference was observed between the measured and the elliptically calculated area. In the midsubstance insertion, significant correlation was observed between the measured and the elliptically calculated area (Pearson's correlation coefficient = 0.603, P = 0.001). However, no correlation was observed in the whole ACL insertion area.Conclusion:The morphology of the femoral ACL insertion resembles an elliptical shape. However, due to the wide variation in morphology, the femoral ACL insertion cannot be considered mathematically elliptical.

Single Bundle ACL Reconstruction: Step by Step

An Anterior Cruciate Ligament (ACL) tear is the most common ligamentous injury of the knees. ACL reconstruction restore stability and kinematics of the knee joint, by improving knee stability. There are so many surgical techniques in ACL reconstruction. One of the most common technique is Single Bundle ACL reconstruction with the hamstring autograft. A good knowledge about operating technique and step by step approach are crucial for successfully procedure. The first step is patient positioning, including the leg holder should be placed proximal enough to allow full knee flexion and extension during procedure, it should be checked before starting the procedure. The second step is graft harvest, the autograft is prepared from the affected knee hamstring muscles, make a proper identification of the Gracilis and Semitendinosus tendon. The third step is portal placement, make a good native ACL attachment identification. Fourth step is femoral tunnel creation, avoid posterior wall blowout. Fifth step is tibial tunnel creation, remaining ACL fibers should be a landmark of the native ACL insertion site. Preserve the meniscal root insertion to prevent iatrogenic meniscus root avulsion. Sixth step is fixation, cycle the knee several times while applying traction to remove any slack out of the graft and to make sure there is non-impingement when fix the graft.

The Chinese ACL injury population has a higher proportion of small ACL tibial insertion sizes than Western patients

PurposeThe study purpose is to characterize the sizes of the anterior cruciate ligament (ACL) insertion site and intercondylar notch in Chinese patients undergoing ACL surgery. The findings will provide a reference for individualized clinical treatment of ACL rupture.MethodsFor this study, 137 patients (102 males, 35 females) with an average age of 30.3 ± 9.5 years (range 14–52 years) undergoing ACL reconstruction were included. The tibial ACL insertion site length and width and the intercondylar notch width were measured on MRI and arthroscopically using a ruler. Descriptive statistics of the patients, the distribution of the measurements and the differences between males and females were calculated.ResultsThe ACL tibial insertion size and intercondylar notch width in Chinese patients with ACL injuries, as obtained by MRI and intra-operatively, exhibited significant individual variability. The tibial ACL insertion site had a mean length of 13.5 ± 2.1 mm and width of 10.9 ± 1.5 mm as measured on MRI and a mean length of 13.3 ± 2.1 mm and width of 11.0 ± 1.6 mm as measured intra-operatively. The mean intercondylar notch width was 15.2 ± 2.4 mm on MRI and the mean length was 15.0 ± 2.5 mm intra-operatively. The inter-rater reliability between MRI and intra-operative measurements confirmed that the two methods were consistent. In 65.7% of individuals, the ACL tibial insertion length was < 14 mm.ConclusionThe distribution of tibial footprint size in Chinese patients is different from that in Western populations. There is a higher proportion of subjects with a tibial footprint size < 14 mm among Chinese patients with ACL injury. Therefore, great care should be taken when treating this population with the double-bundle technique or larger graft options.Level of evidence IV.

The correlation between the femoral anterior cruciate ligament footprint area and the morphology of the distal femur: three-dimensional CT evaluation in cadaveric knees.

"Anatomical" anterior cruciate ligament (ACL) reconstruction is defined as the functional restoration of the ACL to its native dimensions. It is essential to obtain more accurate predictors of ACL size before surgery. The purpose of this study was to investigate the correlation between the native femoral ACL footprint size and the morphology of the distal femur using three-dimensional CT (3D-CT). Thirty non-paired Japanese human cadaver knees were used. All soft tissues around the knee were resected except the ACL. For the evaluation of femoral condyle morphology, trans-epicondylar length (TEL), notch outlet length, axial notch area, and notch width index were measured using 3D-CT. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the boundaries of the ACL insertion site were outlined on the femoral side. An accurate lateral view of the femoral condyle was photographed with a digital camera. The size of the femoral ACL footprint, length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were measured with ImageJ software. Notch height, lateral notch area, and TEL were significantly correlated with the femoral ACL footprint area. Both axial notch area and notch outlet length were significantly correlated with the femoral mid-substance insertion area. Morphological evaluation using 3D-CT preoperatively may be useful in predicting the femoral ACL footprint size.

Femoral Footprint for Anatomical Single-Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study.

PurposeTo identify the femoral footprint of the anterior cruciate ligament (ACL) in Koreans.Materials and MethodsEighteen embalmed cadaveric knees (mean age, 70 years) were examined. First, the shape of the ACL was determined macroscopically. After the ACL femoral footprint was defined, the ACL was cut from the femur and a Kirschner wire was inserted into the center of the ACL, and the position was verified with a C-arm. The position was quantified on the C-arm field using the quadrant method. The length and width of the ACL were measured.ResultsMacroscopically, the ACL is a flat single bundle with an average length of 34 mm and an average width of 9 mm. On average, the center of the ACL insertion site measured with the quadrant method was positioned at 29.5%±2.8% in an anterior direction (from posterior), and at 38.5%±3.2% in a distal direction (from Blumensaat’s line). The anterior and posterior margins of the ACL femoral footprint were the resident’s ridge and the cartilage margin of the lateral femoral condyle, respectively.ConclusionsThe center of the ACL femoral footprint is positioned more anteriorly and distally than the positions identified in previous studies.

Correlations between the anterior cruciate ligament insertion sites dimensions and patient's physical characteristics: an arthroscopic study

Correlations between the anterior cruciate ligament insertion sites dimensions and patient's physical characteristics: an arthroscopic study

The posterior horn of the lateral meniscus is a reliable novel landmark for femoral tunnel placement in ACL reconstruction

Femoral tunnel placement is essential for good outcome in anterior cruciate ligament (ACL) reconstruction. In the past, several attempts have been made to optimize femoral tunnel placement. It was observed that the posterior horn of the lateral meniscus was always located directly below to the desired femoral ACL tunnel position, when the knee was brought to deep flexion (> 120°). The goal of the present study was to verify the hypothesis that the posterior horn of the lateral meniscus can be used as a landmark for femoral tunnel placement. Out of a consecutive series of ACL reconstructions done by a single surgeon, 55 lateral radiographs were evaluated according to the quadrant method by Bernard and Hertel. Additionally, on anterior-posterior radiographs the femoral tunnel angle was determined. In the present case series the posterior horn of the lateral meniscus could be identified and used as a landmark for femoral tunnel placement in all cases. The mean tunnel depth was 24 ± 5.1% and the mean tunnel height was 31.3 ± 5.7%. The mean femoral tunnel angle was 41 ± 4.9° using the anatomical axis as a reference. Compared to previous cadaver studies the data of the present study were within their anatomical range of the native ACL insertion site. The suggested technique using the posterior horn of the lateral meniscus as a landmark for femoral tunnel placement showed reproducible results and matches the native ACL insertion site compared to previous cadaveric studies. In particular, non-experienced ACL surgeons will benefit from this apparent landmark and the corresponding easy-to-use ACL reconstruction method. IV.

Anterior cruciate ligament tibial insertion site is elliptical or triangular shaped in healthy young adults: high-resolution 3-T MRI analysis.

To clarify the morphology of anterior cruciate ligament (ACL) tibial insertion site in healthy young knees using high-resolution 3-T MRI. Subjects were 50 ACL-reconstructed patients with a mean age of 21.4±6.8years. The contralateral healthy knees were scanned using high-resolution 3-T MRI. The tibial insertion sites of the anteromedial (AM) and posterolateral (PL) bundle fibres, and the ACL attachment on the anterior horn of lateral meniscus (AHLM) were segmented from the MR images, and 3D models were reconstructed to evaluate the morphology. The shape of ACL footprint was qualitatively analysed, and the size of AM and PL attachments and AHLM overlapped area was measured digitally. Tibial AM and PL bundles were clearly identified in 42 of 50 knees (84.0%). Morphology of the whole ACL tibial insertion site was elliptical in 23 knees (54.8%) and triangular in 19 knees (45.2%), but not classified as C-shape in any knees. However, the AM bundle attachment was of C-shape in 29 knees (69.0%) and band-like in 13 knees (31.0%). Overlap of ACL on AHLM was found in 26 knees (61.9%), and the size of the overlapped area was 4.8±4.7% of the whole ACL insertion site. 3D morphology of the intact ACL tibial insertion site analysed by high-resolution 3-T MRI was elliptical or triangular in healthy young knees. However, the AM bundle insertion site was of C-shape or band-like. A small lateral portion of the ACL was overlapped with the AHLM. As for clinical relevance, these findings should be considered in order to reproduce the native ACL insertion site sufficiently. III.

Three-dimensional isotropic magnetic resonance imaging can provide a reliable estimate of the native anterior cruciate ligament insertion site anatomy.

This study quantified the error in anterior cruciate ligament (ACL) insertion site location and area estimated from three-dimensional (3D) isotropic magnetic resonance imaging (MRI) by comparing to native insertion sites determined via 3D laser scanning. Isotropic 3D DESS MRI was acquired from twelve fresh-frozen, ACL-intact cadaver knees. ACL insertion sites were manually outlined in each MRI slice, and the resulting contours combined to determine the 3D insertion site shape. Specimens were then disarticulated, and the boundaries of the ACL insertion sites were digitized using a high-accuracy laser scanner. MRI and laser scan insertion sites were co-registered to determine the percent overlapping area and difference in insertion centroid location. Femoral ACL insertion site area averaged 112.7±17.9mm2 from MRI and 109.7±10.9mm2 from laser scan (p=0.345). Tibial insertion area was 134.7±22.9mm2 from MRI and 135.2±15.1mm2 from laser scan (p=0.881). Percentages of overlapping area between modalities were 82.2±10.2% for femurs and 81.0±9.0% for tibias. The root-mean-square differences for ACL insertion site centroids were 1.87mm for femurs and 2.49mm for tibias. The MRI-estimated ACL insertion site centroids were biased on average 0.6±1.6mm proximally and 0.3±1.9mm posteriorly for femurs, and 0.3±1.1mm laterally and 0.5±1.5mm anteriorly for tibias. Errors in ACL insertion site location and area estimated from 3D-MRI were determined via comparison with a high-accuracy 3D laser scanning. Results indicate that MRI can provide estimates of ACL insertion site area and centroid location with clinically applicable accuracy. MRI-based assessment can provide a reliable estimate of the native ACL anatomy, which can be helpful for surgical planning as well as assessment of graft tunnel placement.

The Relationship of Anterior Cruciate Ligament Insertion Sites to the Distal Femoral Growth Centers: an MRI study

The Relationship of Anterior Cruciate Ligament Insertion Sites to the Distal Femoral Growth Centers: an MRI study

The effects of graft size and insertion site location during anterior cruciate ligament reconstruction on intercondylar notch impingement

BackgroundIntercondylar notch impingement is detrimental to the anterior cruciate ligament (ACL). Notchplasty is a preventative remodeling procedure performed on the intercondylar notch during ACL reconstruction (ACLR). This study investigates how ACL graft geometry and both tibial and femoral insertion site location may affect ACL-intercondylar notch interactions post ACLR. A range of ACL graft sizes are reported during ACLR, from six millimeters to 11mm in diameter. Variability of three millimeters in ACL insertion site location is reported during ACLR. This study aims to determine the post-operative effects of minor variations in graft size and insertion location on intercondylar notch impingement. MethodsSeveral 3D finite element knee joint models were constructed using three ACL graft sizes and polar arrays of tibial and femoral insertion locations. Each model was subjected to flexion, tibial external rotation, and valgus motion. Impingement force and contact area between the ACL and intercondylar notch compared well with experimental cadaver data from literature. ResultsA three millimeter anterior–lateral tibial insertion site shift of the maximum size ACL increased impingement force by 242.9%. A three millimeter anterior–proximal femoral insertion site shift of the maximum size ACL increased impingement by 346.2%. Simulated notchplasty of five millimeters eliminated all impingement for the simulation with the greatest impingement. For the kinematics applied, small differences in graft size and insertion site location led to large increases in impingement force and contact area. ConclusionsMinor surgical variations may increase ACL impingement. The results indicate that notchplasty reduces impingement during ACLR. Notchplasty may help to improve ACLR success rates.

Evaluation of the Bone-ligament and tendon insertions based on Raman spectrum and its PCA and CLS analysis

Injuries to the Anterior Cruciate Ligament (ACL) and Rotator Cuff Tendon (RCT) are common in physically active and elderly individuals. The development of an artificial prosthesis for reconstruction/repair of ACL and RCT injuries is of increasing interest due to the need for viable tissue and reduced surgically-related co-morbidity. An optimal prosthesis design is still elusive, therefore an improved understanding of the bone-soft tissue interface is extremely urgent. In this work, Raman spectral mapping was used to analyze, at the micron level, the chemical composition and corresponding structure of the bone-soft tissue interface. Raman spectroscopic mapping was performed using a Raman spectrometer with a 785 nm laser coupled to a microscope. Line-mapping procedure was performed on the ACL and RCT bone insertion sites. The classical least squares (CLS) fitting model was created from reference spectra derived from pure bone and soft-tissue components, and spectral maps collected at multiple sites from ACL and RCT specimens. The results suggest that different source of interface shows different boundary, even they seems have the same components. Compared to the common histology results, it provided intact molecular information that can easily distinguished some relative component change.

A Validation Study of a Novel 3-Dimensional MRI Modeling Technique to Identify the Anatomic Insertions of the Anterior Cruciate Ligament.

Background:Anatomic single bundle anterior cruciate ligament (ACL) reconstruction is the current gold standard in ACL reconstructive surgery. However, placement of femoral and tibial tunnels at the anatomic center of the ACL insertion sites can be difficult intraoperatively. We developed a “virtual arthroscopy” program that allows users to identify ACL insertions on preoperative knee magnetic resonance images (MRIs) and generates a 3-dimensional (3D) bone model that matches the arthroscopic view to help guide intraoperative tunnel placement.Purpose:To test the validity of the ACL insertion sites identified using our 3D modeling program and to determine the accuracy of arthroscopic ACL reconstruction guided by our “virtual arthroscopic” model.Study Design:Descriptive laboratory study.Methods:Sixteen cadaveric knees were prescanned using routine MRI sequences. A trained, blinded observer then identified the center of the ACL insertions using our program. Eight knees were dissected, and the centers of the ACL footprints were marked with a screw. In the remaining 8 knees, arthroscopic ACL tunnels were drilled into the center of the ACL footprints based on landmarks identified using our virtual arthroscopic model. Postprocedural MRI was performed on all 16 knees. The 3D distance between pre- and postoperative 3D centers of the ACL were calculated by 2 trained, blinded observers and a musculoskeletal radiologist.Results:With 2 outliers removed, the postoperative femoral and tibial tunnel placements in the open specimens differed by 2.5 ± 0.9 mm and 2.9 ± 0.7 mm from preoperative centers identified on MRI. Postoperative femoral and tibial tunnel centers in the arthroscopic specimens differed by 3.2 ± 0.9 mm and 2.9 ± 0.7 mm, respectively.Conclusion:Our results show that MRI-based 3D localization of the ACL and our virtual arthroscopic modeling program is feasible and does not show a statistically significant difference to an open arthrotomy approach. However, additional refinements will be required to improve the accuracy and consistency of our model to make this an effective tool for surgeons performing anatomic single-bundle ACL reconstructions.Clinical Relevance:Arthroscopic anatomic single-bundle ACL reconstruction is the current gold standard for ACL reconstruction; however, the center of the ACL footprint can be difficult to identify arthroscopically. Our novel modeling can improve the identification of this important landmark intraoperatively and decrease the risk of graft malposition and subsequent graft failure.

Radiographic femoral bicondylar width predicts anterior cruciate ligament insertion site sizes.

The purpose of this study was to determine whether radiographic femoral bicondylar width predicts intra-operative anterior cruciate ligament (ACL) insertion site sizes. Seventy-three consecutive patients (39 males and 34 females; mean age 25.2years±10.2) who underwent anatomic ACL reconstruction were retrospectively reviewed. Femoral condyle width was measured using a pre-operative anteroposterior (AP) radiograph of the operative knee. Lines were drawn through the anatomic axis of the femur, as well as perpendicularly through the condyles. Bicondylar width was measured as the maximum width across both the medial and lateral femoral condyles utilizing this perpendicular line. The ACL insertion site lengths (in the AP direction) of both the tibia and the femur were measured intra-operatively using a commercially available arthroscopic ruler. The average bicondylar width was significantly smaller for females compared to males (p<0.05). The average tibial and femoral insertion site sizes were significantly smaller for females compared to males (p<0.05). Regression analysis predicted tibial (r 2=0.88) and femoral (r 2=0.90) insertion site sizes based on femoral bicondylar width measurements. A simple radiographic measurement of femoral bicondylar width can predict intra-operative tibial and femoral insertion site sizes, which has the potential to assist surgeons in performing individualized ACL reconstruction in cases where MRI scan is unavailable. IV.