Normal Anterior Cruciate Ligament Research Articles

Nanosurgical and Bioengineering Treatment of Human Anterior Cruciate Ligament Tears with Ultrasound-Guided Injection of Modified Platelet-Rich Plasma Using Human Cell Memory Based on Clinical, Ultrasound, MRI, and Nanoscope Analyses: A Double-Blind Randomized Trial.

Background: Anterior cruciate ligament (ACL) tears account for 40% to 50% of all ligamentous knee injuries. Most patients with ACL ruptures undergo surgical treatment. There is currently no objective, well-documented, repeatable, and standardized nonsurgical method for ACL tear treatment. This study aimed to investigate ACL outcomes in patients who underwent a novel nanosurgery and bioengineering treatment (NSBT) for an ACL tear. Methods: This was a double-blind randomized trial including 44 patients with a history of traumatic knee injury and a confirmed ACL tear. The final sample comprised 40 patients who met all the eligibility criteria. The patients were divided into two groups: the treatment group (n = 30) and the control group (n = 10). The treatment group underwent nanosurgery with an ultrasound-guided injection of modified platelet-rich plasma (PRP) using human cell memory (RP-hCM). The control group was treated with an ultrasound-guided PRP injection into the joint capsule. At baseline and post-treatment, all patients underwent both ultrasonography and magnetic resonance imaging (MRI), and the following clinical variables were assessed: the WOMAC score, the Lysholm knee score, the visual analog scale score, and knee instability. In most patients, the clinical outcome was verified using nanoscopy. Results: The median WOMAC, VAS, and LKS scores, as well as knee instability, improved significantly 12 weeks after the procedure in the treatment group (p < 0.001). We found a significantly larger improvement in the assessed parameters in the treatment group compared to the control group (p < 0.001). In the treatment group, all the patients had good and very good clinical outcomes, while 90% of the patients had a normal ACL signal in a follow-up MRI scan. In the control group, a physical examination revealed no changes in knee stability after treatment. Conclusions: This study showed that there is a significant difference in patient experience and the duration of recovery for patients with ACL tears treated with NSBT. The novel nonsurgical method was shown to be repeatable, objective, well documented, standardized, and highly effective.

Intermediate-Term Clinical Outcomes of High-Density Autologous Chondrocyte Implantation in Patients with Concomitant Anterior Cruciate Ligament Reconstruction and Focal Chondral Lesions.

To investigate intermediate-term clinical results in patients with concomitant anterior cruciate ligament (ACL) reconstruction and chondral defect treated with high-density autologous chondrocyte implantation (HD-ACI) compared to patients without ACL tear but with a chondral lesion and HD-ACI treatment. Forty-eight patients with focal chondral lesions underwent HD-ACI (24 with ACL reconstruction after an ACL injury and 24 with an intact ACL). Follow-up assessments occurred at 6, 12, and 24 months. Patient-reported knee function and symptoms were assessed using the International Knee Documentation Committee (IKDC) questionnaire, pain was measured using the Visual Analog Scale (VAS), and adverse events were monitored. Physical activity was assessed using the Tegner Activity Level Scale, and cartilage healing was evaluated with the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. No significant adverse events occurred during follow-up. Both groups showed significant improvements at 2 years compared to baseline (VAS: 8.0 ± 1.3 to 1.4 ± 2.0 [normal ACL]; 7.4 ± 2.3 to 2.1 ± 2.3 [ACL reconstruction]; IKDC: 39.2 ± 10.6 to 76.1 ± 22.0 [intact ACL]; 35.6 ± 12.1 to 74.6 ± 20.9 [ACL reconstruction]). Patients in both groups exceeded the minimal clinically important difference (MCID) for IKDC scores. The Tegner Activity Level Scale decreased immediately after surgery and increased after 2 years, with 70.6% (normal ACL) and 89.5% (ACL reconstruction) returning to their preinjury activity levels. No significant differences in the MOCART score were observed between the groups. ACL reconstruction does not appear to reduce the outcomes (at 2 years) of HD-ACI.

Application of machine learning-based multi-sequence MRI radiomics in diagnosing anterior cruciate ligament tears

ObjectiveTo compare the diagnostic power among various machine learning algorithms utilizing multi-sequence magnetic resonance imaging (MRI) radiomics in detecting anterior cruciate ligament (ACL) tears. Additionally, this research aimed to create and validate the optimal diagnostic model.MethodsIn this retrospective analysis, 526 patients were included, comprising 178 individuals with ACL tears and 348 with a normal ACL. Radiomics features were derived from multi-sequence MRI scans, encompassing T1-weighted imaging and proton density (PD)-weighted imaging. The process of selecting the most reliable radiomics features involved using interclass correlation coefficient (ICC) testing, t tests, and the least absolute shrinkage and selection operator (LASSO) technique. After the feature selection process, five machine learning classifiers were created. These classifiers comprised logistic regression (LR), support vector machine (SVM), K-nearest neighbors (KNN), light gradient boosting machine (LightGBM), and multilayer perceptron (MLP). A thorough performance evaluation was carried out, utilizing diverse metrics like the area under the receiver operating characteristic curve (ROC), specificity, accuracy, sensitivity positive predictive value, and negative predictive value. The classifier exhibiting the best performance was chosen. Subsequently, three models were developed: the PD model, the T1 model, and the combined model, all based on the optimal classifier. The diagnostic performance of these models was assessed by employing AUC values, calibration curves, and decision curve analysis.ResultsOut of 2032 features, 48 features were selected. The SVM-based multi-sequence radiomics outperformed all others, achieving AUC values of 0.973 and 0.927, sensitivities of 0.933 and 0.857, and specificities of 0.930 and 0.829, in the training and validation cohorts, respectively.ConclusionThe multi-sequence MRI radiomics model, which is based on machine learning, exhibits exceptional performance in diagnosing ACL tears. It provides valuable insights crucial for the diagnosis and treatment of knee joint injuries, serving as an accurate and objective supplementary diagnostic tool for clinical practitioners.

Valid and reliable diagnostic performance of dual-energy CT in anterior cruciate ligament rupture

ObjectivesTo determine whether dual-energy CT (DECT) can be used to accurately and reliably detect anterior cruciate ligament (ACL) rupture.Materials and methodsParticipants with unilateral ACL rupture were prospectively enrolled, and the bilateral knees were scanned by DECT. A tissue-specific mapping algorithm was applied to improve the visualization of the ACLs. The 80-keV CT value, mixed-keV CT value, electron density (Rho), and effective atomic number (Zeff) were measured to quantitatively differentiate torn ACLs from normal ACLs. MRI and arthroscopy served as the reference standards.ResultsFifty-one participants (mean age, 27.0 ± 8.7 years; 31 men) were enrolled. Intact and torn ACLs were explicitly differentiated on color-coded DECT images. The 80-keV CT value, mixed-keV CT value, and Rho were significantly lower for the torn ACLs than for the intact ACLs (p < 0.001). The optimal cutoff values were an 80-keV CT value of 61.8 HU, a mixed-keV CT value of 60.9 HU, and a Rho of 51.8 HU, with AUCs of 98.0% (95% CI: 97.0–98.9%), 99.2% (95% CI: 98.6–99.7%), and 99.8% (95% CI: 99.6–100.0%), respectively. Overall, DECT had almost perfect reliability and validity in detecting ACL integrity (sensitivity = 97.1% [95% CI: 88.1–99.8%]; specificity = 98.0% [95% CI: 89.5–99.9%]; PPV = 98.0% [95% CI: 93.0–99.8%]; NPV = 97.1% [95% CI: 91.7–99.4%]; accuracy = 97.5% [95% CI: 94.3–99.2%]). There was no evidence of a difference between MRI and DECT in the diagnostic performance (p > 0.99).ConclusionDECT has excellent diagnostic accuracy and reliability in qualitatively and quantitatively diagnosing ACL rupture.Clinical relevance statementDECT could validly and reliably diagnose ACL rupture using both qualitative and quantitative methods, which may become a promising substitute for MRI to evaluate the integrity of injured ACLs and the maturity of postoperative ACL autografts.Key Points• On color-coded DECT images, an uncolored ACL was a reliable sign for qualitatively diagnosing ACL rupture.• The 80-keV CT value, mixed-keV CT value, and Rho were significantly lower for the torn ACLs than for the intact ACLs, which contributed to the quantitative diagnosis of ACL rupture.• DECT had an almost perfect diagnostic performance for ACL rupture, and diagnostic capability was comparable between MRI and DECT.

Augmenting ACL Repair With Suture Tape Improves Knee Laxity: A Biomechanical Study.

Anterior cruciate ligament (ACL) repair is an alternative to reconstruction; however, suture tape support may be necessary to achieve adequate outcomes. To investigate the influence of suture tape augmentation (STA) of proximal ACL repair on knee kinematics and to evaluate the effect of the 2 flexion angles of suture tape fixation. Controlled laboratory study. Fourteen cadaveric knees were tested using a 6 degrees of freedom robotic testing system under anterior tibial (AT) load, simulated pivot-shift (PS) load, and internal rotation (IR) and external rotation loads. Kinematics and in situ tissue forces were evaluated. Knee states tested were (1) ACL intact, (2) ACL cut, (3) ACL repair with suture only, (4) ACL repair with STA fixed at 0° of knee flexion, and (5) ACL repair with STA fixed at 20° of knee flexion. ACL repair alone did not restore the intact ACL AT translation at 0°, 15°, 30°, or 60° of flexion. Adding suture tape to the repair significantly decreased AT translation at 0°, 15°, and 30° of knee flexion but not to the level of the intact ACL. With PS and IR loadings, only ACL repair with STA fixed at 20° of flexion was not significantly different from the intact state at all knee flexion angles. ACL suture repair had significantly lower in situ forces than the intact ACL with AT, PS, and IR loadings. With AT, PS, and IR loadings, adding suture tape significantly increased the in situ force in the repaired ACL at all knee flexion angles to become closer to that of the intact ACL state. For complete proximal ACL tears, suture repair alone did not restore normal knee laxity or normal ACL in situ force. However, adding suture tape to augment the repair resulted in knee laxity closer to that of the intact ACL. STA with fixation at 20° of knee flexion was superior to fixation with the knee in full extension. The study findings suggest that ACL repair with STA fixed at 20° could be considered in the treatment of femoral sided ACL tears in the appropriate patient population.

A STUDY OF FUNCTIONAL OUTCOME OF ACL RECONSTRUCTION WITH ANATOMICAL HAMSTRING TENDON AUTOGRAFT

Background: The Anterior Cruciate ligament (ACL) is the primary stabilizer of the knee and prevents the knee against anterior translation. It is also important in counteracting rotational and valgus stress. Anterior Cruciate Ligament (ACL) reconstruction is an established and widely practiced surgical procedure with proven efcacy and a low morbidity prole. The arthroscopically aided approach has the advantages of smaller skin and capsular incisions, improved viewing of the intercondylar notch for placement of the tunnel and attachment sites, less postoperative pain, fewer adhesions, earlier motion, and easier rehabilitation. The advantages with anatomical hamstring grafts are availability of a greater sectional area and unaffected integrity of the extensor mechanism. Moreover tensile strength of quadrupled anatomical hamstring is found to be even better than a normal ACL. The rate of complications like extension loss, anterior knee pain and surgical site infections was also lower than other procedures. Cortical suspension devices have the necessary biomechanical properties with regard to ultimate failure strength, displacement, and stiffness for initial xation of soft tissue in the femoral tunnel for ACL reconstruction. The aperture xation methods like the interference screws allows for early rm xation and heal with tight bone-tendon interface. To evalua Objectives: te functional outcome of arthroscopy assisted ACL reconstruction with anatomical hamstring tendon graft using Endobutton and Bioabsorbable interference screw and tibial disc. The Methodology: study results included 30 patients admitted with clinical and radiological deciency of ACL during October 2021 to December 2022, in Department of Orthopaedics, SMIMER Hospital, Surat. Study aims to assess the functional outcome of arthroscopy assisted anterior cruciate ligament reconstruction with anatomical hamstring tendon graft using Endobutton and Bioabsorbable interference screw and tibial disc in terms of range of motion, postoperative knee stability, graft site morbidity, subjective knee functions and prospective assessment of functional outcome using Tegner Lysholm knee scoring system. All the patients included in the s Results: tudy were 23 male and 2 female patient. The analysis of the studied cases revealed that the most common affected age group was between 18 to 24 years .. Majority of patients were operated more than 6 months after injury. Sports/BPET (Battle Physical Efciency Test) injuries was the most common mode of injury. The mean size of graft used was 8.2±0.39.Post-operatively at 3, 6, 12month follow up,1 case (4%) had a positive Pivot shift test with a "Glide" (Grade-I), whereas remaining 24 cases (96%) had a negative Pivot shift test. None of the patients had grade III laxity. The mean postoperative Lysholm score improved from preoperative score of 66±5.2 to 88.70±5.54. The overall satisfactory result (excellent + good) at follow up was 95%. All the patients had returned to preinjury level of activity. ACL injuries are common in younger age group individuals. S Conclusion: ports related injury and RTA are the most common modes of injury. Arthroscopy assisted ACL reconstruction using Anatomical hamstring tendon autograft provides a stable knee, reduces postoperative morbidity and enables early rehabilitation. Graft xation using endobutton and and Bioabsorbable interference screw will help the graft to facilitate graft tunnel healing and also maintain its strength until there is a good graft to bone healing occurs. It allows the patients to return to preinjury level of activity, allows the patient to squat, sit crossed leg and climb stairs without difculty. Degeneration of the articular surfaces rarely occurs and the re-operation rates are minimal.

Imaging the pediatric anterior cruciate ligament: not little adults.

An increased incidence of anterior cruciate ligament (ACL) injuries in children over the last few decades has led to a corresponding increase in ACL reconstruction procedures in children. In this review, we will illustrate unique features seen when imaging the ACL in children versus adults. After briefly reviewing relevant normal ACL anatomy, we will review imaging findings of congenital ACL dysplasia. This is followed by a discussion of imaging ACL avulsions. Lastly, we will review the different types of ACL reconstruction procedures performed in skeletally immature children and their post-operative appearances.

Knee anatomic geometry accurately predicts risk of anterior cruciate ligament rupture.

Certain anatomical characteristics of the knee have potential relationships with the risk of anterior cruciate ligament (ACL) rupture. There remains a need for stronger evidence using arthroscopy as well as radiological imaging to accurately clarify these relationships. To compare the anatomic geometry of the knee joint between patients with and without ACL ruptures. Case-controlled study of patients with arthroscopically confirmed ACL ruptures (ACL group) compared to patients with arthroscopically confirmed normal ACLs (control group). Magnetic resonance imaging scans were assessed for a total of 14 quantitative radiological variables including medial and lateral tibial slope angles (bone and cartilage measurements), meniscal height, femoral width, intercondylar notch width and tibial depth. A total of 105 patients were included in the study, 55 in the ACL group and 50 in the control group. There was a significant difference (P < 0.05) of most of the radiological measurements between the two groups. There was also a significant difference (P < 0.05) when comparing the variables between sexes. Multiple logistic regression analysis produced a mathematical model utilizing all the radiological measurements with 92.6% classification accuracy in predicating an ACL rupture with the medial tibial slope angle being the strongest predicator variable (odds ratio = 8.97, P = 0.011). Greater postero-inferior directed slope measurements of bone and cartilage in both the lateral and medial compartments with a narrower intercondylar notch width increase the risk of ACL rupture. Mathematical modelling can accurately predict the risk of ACL rupture.

A prospective study to evaluate the functional and clinical outcome of anterior cruciate ligament reconstruction with standard hamstring autograft

Background: The anterior cruciate ligament (ACL) is the primary stabilizer of the knee and prevents the knee against anterior translation. It is also important in counteracting rotational and valgus stress. The arthroscopically aided approach has the advantages of smaller skin and capsular incisions, improved viewing of the intercondylar notch for placement of the tunnel and attachment sites, less postoperative pain, fewer adhesions, earlier motion, and easier rehabilitation. The advantages with semitendinosus grafts are the availability of a greater sectional area and the unaffected integrity of the extensor mechanism. Moreover, the tensile strength of quadrupled hamstring is found to be even better than a normal ACL. The rate of complications such as extension loss, anterior knee pain, and surgical site infections was also lower than in other procedures such as in BPTB grafts. Cortical suspension devices have the necessary biomechanical properties with regard to ultimate failure strength, displacement, and stiffness for the initial fixation of soft tissue in the femoral tunnel for ACL reconstruction. The aperture fixation methods such as the interference screws allow for early firm fixation and heal with a tight bone–tendon interface.Objective: A prospective study to evaluate the functional and clinical outcome of ACL reconstruction with standard hamstring autograft.Materials and Methods: The study results included 30 patients admitted with clinical and radiological deficiency of ACL from September 2019 to March 2021 using endobutton and bioabsorbable interference screw in terms of range of motion, postoperative knee stability, subjective knee functions, and prospective assessment of functional outcome using Tegner Lysholm knee scoring system.Results: Sports injuries were the most common mode of injury (n = 17, 56.7%). The mean size of graft used was 8.2 ± 0.39 mm. Postoperatively at 2-year follow-up, 30 cases (100%) had 0 grade pivot-shift test, 0 grade Lachman test, and anterior drawer test. The mean postoperative Lysholm score improved from preoperative score of 62.83 ± 5.2–91.0 ± 5.54. The overall satisfactory result (excellent + good) at 6-month follow-up was (excellent – 30 and good – 70) 100%. Out of this, 27 (90%) patients had returned to preinjury level of activity in 1 year. In this study, one patient had superficial infection and two patients had knee pain.Conclusion: Arthroscopy-assisted ACL reconstruction using hamstring tendon autograft provides a stable knee, reduces postoperative morbidity, and enables early rehabilitation.

Anterior cruciate ligament autograft maturation on sequential postoperative MRI is not correlated with clinical outcome and anterior knee stability

PurposeMagnetic resonance imaging (MRI) signal intensity is correlated to structural postoperative changes of the anterior cruciate ligament (ACL) autograft. The purpose of this study was to investigate the ACL autograft maturation process via MRI over 2 years postoperatively, compare it to a native ACL signal and correlate the results with clinical outcome, return to preinjury sports levels, and knee laxity measurements.MethodsACL autograft signal intensity was measured in 17 male patients (age, 28.3 ± 7.0 years) who underwent ACL reconstruction with hamstring autograft at 6 weeks, 3-, 6-, 12-, and 24 months postoperatively by 3 Tesla MRI. Controls with an intact ACL served as control group (22 males, 8 females; age, 26.7 ± 6.8 years). An ACL/PCL ratio (APR) and ACL/muscle ratio (AMR) was calculated to normalize signals to soft tissue signal. APR and AMR were compared across time and to native ACL signal. Clinical outcome scores (IKDC, Lysholm), return to preinjury sports levels (Tegner activity scale), and knee laxity measurement (KT-1000) were obtained and correlated to APR and AMR at the respective time points.ResultsThe APR and AMR of the ACL graft changed significantly from the lowest values at 6 weeks to reach the highest intensity after 6 months (p < 0.001). Then, the APR and AMR were significantly different from a native ACL 6 months after surgery (p < 0.01) but approached the APR and AMR of the native ACL at 1- and 2 years after surgery (p < 0.05). The APR changed significantly during the first 2 years postoperatively in the proximal (p < 0.001), mid-substance (p < 0.001), and distal (p < 0.01) intraarticular portion of the ACL autograft. A hypo-intense ACL MRI signal was associated with return to the preinjury sports level (p < 0.05). No correlation was found between ACL MRI graft signal and clinical outcome scores or KT-1000 measurements.ConclusionACL grafts undergo a continuous maturation process in the first 2 years after surgery. The ACL graft signals became hyper-intense 6 months postoperatively and approximated the signal of a native intact ACL at 12- and 24 months. Patients with a hypo-intense ACL graft signal at 2 years follow-up were more likely to return to preinjury sports levels. The results of the present study provide a template for monitoring the normal ACL maturation process via MRI in case of prolonged clinical symptoms. However, subjective outcome and clinical examination of knee laxity remain important to assess the treatment success and to allow to return to sports.Level of evidenceIII.

Radiological Evaluation of Femoral Intercondylar Notch and Tibial Intercondylar Eminence Morphometries in Anterior Cruciate Ligament Pathologies Using Magnetic Resonance Imaging.

To determine the relationship between femoral-tibial morphometries and anterior cruciate ligament (ACL) pathologies using magnetic resonance imaging (MRI). We retrospectively evaluated 455 patients (211 females and 244 males) who underwent knee MRI with suspected ACL pathology. Imaging findings were classified as normal ACL (n = 119), degeneration of the ACL (n = 116), partial ACL tear (n = 103), and complete ACL tear (n = 117). In all groups, the femoral intercondylar notch width (INW), intercondylar distance (CD), notch width index (NWI), and intercondylar notch angle (INA), the angles between the tibial plateau and tibial spines (MPA and LPA), intercondylar eminence peak angle (IEA), and tibial slope angles (MSA and LSA) were measured. Femoral INW and NWI were significantly lower in patients with ACL pathology (p < 0.05). They were also lower in patients with tear compared to degeneration. The INA was significantly smaller in patients with ACL pathology (p < 0.001) and the significance continued in both genders. The LSA was only increased in patients with complete tear (p < 0.01) and the difference seems existing in both genders. It was also found that the LPA and IEA demonstrated significant increases in patients with ACL pathology (p < 0.01 and < 0.05, respectively) and the significance in LPA continued in both genders. Significant differences between males and females were found for the INW and CD in all 4 groups (p < 0.001). In addition, the INA, LPA and LSA were independent predictors in determining the risk of ACL pathology. The ACL pathologies are associated with femoral-tibial morphometries and these associations exist in both genders. The online version contains supplementary material available at 10.1007/s43465-021-00490-7.

Anteromedial meniscofemoral ligament–A rare finding

We report a case of a 49-year-old patient presenting an anteromedial meniscofemoral ligament (AMMFL) on both knees with a tear of this ligament in the left knee associated to a normal anterior cruciate ligament (ACL). The AMMFL is a relatively rare anatomic structure that may correspond to a variant of the ACL type anterior root insertion of the medial meniscus. The findings reported in the literature were in most part results of incidental situations. AMMFL can be visualized through magnetic resonance imaging (MRI) and arthroscopy.

Anterior cruciate ligament abnormalities are associated with accelerated progression of knee joint degeneration in knees with and without structural knee joint abnormalities: 96-month data from the Osteoarthritis Initiative

To compare progression over 8 years in knee compositional cartilage degeneration and structural joint abnormalities in knees with different types of anterior cruciate ligament (ACL) abnormalities over 8 years. Baseline MR images of the right knees of 1899 individuals of the Osteoarthritis Initiative (OAI) with no evidence of or mild to moderate radiographic osteoarthritis were assessed for nontraumatic ACL abnormalities. The knees of 91 individuals showed nontraumatic ACL abnormalities (age 60.6±9.8y, 46 females; mucoid degeneration (MD), N=37; complete tear (CT), N=22; partial tear (PT), N=32) and were frequency-matched to 91 individuals with normal ACL. MRIs were assessed for knee joint abnormalities using the Whole-Organ Magnetic Resonance Imaging Score (WORMS) and cartilage T2 mapping at baseline, 4- and 8-year follow-up. Over 8 years, cartilage T2 values of the medial tibia showed a significantly greater increase in individuals with MD, PT or CT compared to those with normal ACL (adjusted rate of change/year [95% confidence interval], normal ACL: 0.06 [0.01, 0.23], MD: 0.34 [0.07, 0.73], PT, 0.21 [0.02, 0.33], CT, 0.51 [0.16, 0.78]), indicating an association of ACL abnormalities and an increased progression rate of cartilage degeneration in subjects with and without knee joint degeneration. This effect was also seen in cartilage T2 values averaged over all compartments (normal ACL: 0.08 [0.05, 0.20] vs abnormal ACL: 0.27 [0.06, 0.56]). Over 8 years, higher progression rates of cartilage degeneration, especially in the medial tibia, were associated with ACL abnormalities compared to those with normal ACL, in subjects with and without knee joint abnormalities.

Coronal Lateral Collateral Ligament Sign: A Novel Magnetic Resonance Imaging Sign for Identifying Anterior Cruciate Ligament–Deficient Knees in Adolescents and Summarizing the Extent of Anterior Tibial Translation and Femorotibial Internal Rotation

Background: Incompetence of the anterior cruciate ligament (ACL) confers knee laxity in the sagittal and axial planes that is measurable with clinical examination and diagnostic imaging. Hypothesis: An ACL-deficient knee will produce a more vertical orientation of the lateral collateral ligament (LCL), allowing for the entire length of the LCL to be visualized on a single coronal slice (coronal LCL sign) on magnetic resonance imaging. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Charts were retrospectively reviewed from April 2009 to December 2017 for all patients treated with ACL reconstruction (constituting the ACL-deficient cohort). A control cohort was separately identified consisting of patients with a normal ACL and no pathology involving the collateral ligaments or posterior cruciate ligament. Patients were excluded for follow-up <2 years, incomplete imaging, and age >19 years. Tibial translation and femorotibial rotation were measured on magnetic resonance images, and posterior tibial slope was measured on a lateral radiograph of the knee. Imaging was reviewed for the presence of the coronal LCL sign. Results: The 153 patients included in the ACL-deficient cohort had significantly greater displacement than the 70 control patients regarding anterior translation (5.8 vs 0.3 mm, respectively; P < .001) and internal rotation (5.2° vs −2.4°, P < .001). Posterior tibial slope was not significantly different. The coronal LCL sign was present in a greater percentage of ACL-deficient knees than intact ACL controls (68.6% vs 18.6%, P < .001). The presence of the coronal LCL sign was associated with greater anterior tibial translation (7.2 vs 0.2 mm, P < .001) and internal tibial rotation (7.5° vs –2.4°, P = .074) but not posterior tibial slope (7.9° vs 7.9°, P = .973) as compared with its absence. Multivariate analysis revealed that the coronal LCL sign was significantly associated with an ACL tear (odds ratio, 12.8; P < .001). Conclusion: Our study provides further evidence that there is significantly more anterior translation and internal rotation of the tibia in the ACL-deficient knee and proves our hypothesis that the coronal LCL sign correlates with the presence of an ACL tear. This coronal LCL sign may be of utility for identifying ACL tears and anticipating the extent of axial and sagittal deformity.

Association Between MRI-Based Tibial Slope Measurements and Mucoid Degeneration of the Anterior Cruciate Ligament: A Propensity Score-Matched Case-Control Study.

Background:The cause of mucoid degeneration (MD) of the anterior cruciate ligament (ACL), which is commonly observed on magnetic resonance imaging (MRI) of patients with knee pain, has yet to be elucidated. Despite the limited evidence on the relationship between ACL lesions (injury and MD) and tibial morphologic features (ie, posterior tibial slope), the potential association between the presence of ACL MD and medial and lateral tibial slope (MTS and LTS) has not been well-established.Purpose:To investigate whether MTS and LTS measurements are associated with the presence of ACL MD.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Consecutive knee MRI examinations of patients referred by an orthopaedic surgeon for potential internal joint derangements were identified within a 4-year period. The presence of ACL MD and the MTS/LTS values were assessed by independent expert observers in consensus in a blinded fashion. From 413 consecutive knee MRI scans, a sample of 80 knees, including 32 knees with ACL MD (cases) and 48 knees with normal ACL (controls), were selected using propensity score matching method for age, sex, body mass index, and presence of severe medial tibiofemoral compartment cartilage damage. The association between ACL MD and MTS/LTS was evaluated using conditional regression models.Results:Knees with ACL MD had higher values of LTS (mean ± SD, 7.18° ± 3.58°) in comparison with control knees (5.32° ± 3.35°). Conditional regression analysis revealed a significant association between LTS measurements (not MTS) and ACL MD; every 1° increase in LTS was associated with a 17% (95% CI, 1%-35%) higher probability of having ACL MD.Conclusion:Excessive LTS was associated with the presence of ACL MD, independent of participants’ age, sex, BMI, and cartilage damage severity.

Diffusion Tensor Imaging for Quantitative Assessment of Anterior Cruciate Ligament Injury Grades and Graft.

As the need for quantitative assessment of anterior cruciate ligament (ACL) injuries and ACL graft increases, diffusion tensor imaging (DTI) becomes a more valuable measuring tool. However, DTI changes in differing injury grades of ACL and longitudinal graft remain unclear. To investigate the diagnostic performance of DTI in quantitatively assessing ACL injury severity and the development of ACL grafts within 6 months of surgery. A cohort study. Thirty-five patients diagnosed with grades I-IV ACL injuries and 20 volunteers as controls were recruited. T1 -weighted, T2 -weighted, proton density (PD)-weighted, and DTI at 3.0T MRI. ACL injury grades in arthroscopic images and DTI quantitative data were evaluated from July 2016 to July 2018. Chi-square test, analysis of variance, Spearman correlation analysis, and receiver operator characteristic (ROC) curves. Both fractional anisotropy (FA) (r = -0.898, P < 0.05) and apparent diffusion coefficient (ADC) (r = 0.851, P < 0.05) were significantly correlated with the severity of ACL injuries. The area under the curve (AUC) values for differentiation between low- and high-grade ACL injuries with FA and ADC were 0.973 and 0.963, respectively. Although there were no significant differences in FA (P > 0.05) and ADC (P > 0.05) between grades I and II ACL injuries or in ADC (P > 0.05) between grades III and IV, there were significant differences in FA and ADC between two grades (P < 0.05). There were significant differences in FA (P < 0.05) and ADC (P < 0.05) between normal ACL and 3-month graft postoperation, as well as in ADC values between 3-month and 6-month graft postoperation (P < 0.05). DTI could be used to quantitatively evaluate the ACL injury grades and the development of ACL grafts. The diagnostic efficiency of FA values was higher than that of ADC values. 1 TECHNICAL EFFICACY: Stage 3.

Quantitative assessment of neural elements in a rat model using nerve growth factor after remnant-preserving anterior cruciate ligament reconstruction: a histological and immunofluorescence pilot study

BackgroundImmunofluorescence analyses of anterior cruciate ligament (ACL) allografts following remnant-preserving ACL reconstruction using Achilles tendon allografts have provided evidence for the presence of neural elements. In this study, we aimed to examine the expression of neural elements and quantify the presence of neural cells in ACL remnants and Achilles allografts using nerve growth factor (NGF) therapy after remnant-preserving ACL reconstruction.MethodsExperiments were conducted on 5 pairs of rats (approximately 8 weeks old and weighing 320 g at the time of surgery). Longitudinally, split Achilles tendons from the paired rats were freshly frozen and later defrosted with warm saline and allografted onto the right ACL of the other rat that was partially detached at the femoral attachment site. A sham operation was conducted on the left knee to be used as a control. NGF was injected into both knee joints every week for 6 weeks after surgery. The presence of neural cells in the ACL of the sham-operated knee, allografted Achilles tendon, and ACL remnant was examined 6 weeks post-surgery using H and E and immunofluorescent staining.ResultsH and E staining did not reveal neural cells in any of the three groups. However, immunofluorescence analysis showed the presence of nestin-positive neural elements in the normal ACL tissues as well as ACL remnants. Additionally, neural elements were examined in 7 of the 8 (87.5%) allograft tissues. Quantitative analysis showed no difference in the number or area of nuclei among the three groups. However, the number and area of neural cells in the Achilles allografts were significantly lower than those in the other two groups (p = 0.000 and p = 0.001, respectively).ConclusionOur observations indicate that ACL remnants promote the new ingrowth and persistence of neural cells. We suggest that the ingrowth of neural elements can support the persistence and new ingrowth of mechanoreceptors, thereby enhancing the functional stability of knee joints. Moreover, the expression of neural cells in the Achilles allografts was lower than that in normal ACL tissues and ACL remnants in the quantitative evaluation, thereby confirming the essential role of ACL remnants in knee joint functionalization.

ACL Growth With Age in Pediatric Patients: An MRI Study.

There is limited knowledge of morphologic changes of the anterior cruciate ligament (ACL) during childhood. The purpose of the study is to describe normal ACL growth in pediatric patients. We performed retrospective review of patients under 19 years of age with at least 2 serial magnetic resonance imaging (MRI) examinations of the same knee without ACL tear. The parameters measured included length of the ACL, width of the ACL in sagittal and coronal planes, physeal status, ACL-tibial inclination angle, Notch Width Index, ACL tibial attachment width and midpoint, and anterior to posterior length and height of the tibial epiphysis. Pearson correlation coefficients were calculated to determine the strength of correlation of each parameter relative to age. Growth curves were calculated for individual parameters, producing a predictive model for growth of the ACL over time. One hundred forty-seven patients (365 MRIs) were included. The average age at initial MRI was 12.2 years (range: 1.2 to 18.4 y). The Pearson correlation coefficient for each parameter was statistically significant relative to age. Younger patients had more oblique, anteriorly attached ACLs. Three distinct phases of growth were observed: patients age 1.5 to 5.75 years average 2.25 mm of growth per year; patients aged 6 to 11.5 average 1.46 mm of growth per year; growth slows at age 11.75, stopping by 18.5 years. The growth model for ACL sagittal width increased 0.45 mm/y from age 1.5 to 14.5 after which it plateaus, whereas coronal width increased 0.22 mm/y from age 1.5 to 18.75. In the pediatric patient, the ACL grows in length and width in a predictable manner until age 18. This model aids clinicians in predicting normal ACL parameters for anatomic reconstruction procedures in the skeletally immature patient. Level IV.

Fibrocartilaginous metaplasia and neovascularization of the anterior cruciate ligament in patients with osteoarthritis.

The anterior cruciate ligament (ACL) prevents the anterior translocation and medial rotation of the tibia against the femur. It is typically composed of dense regular connective tissue (DRCT), small amount of loose connective tissue, little vasculature, and few nerve endings. The objective of the current study was to evaluate the details of histological changes in ACLs of patients with clinically diagnosed osteoarthritis (OA). The ACLs of six patients undergoing total knee replacement because of OA (OA group) were compared with 16 normal ACLs from cadavers (control). The ACLs were analyzed for tissue composition and number of blood vessels across the full length and thickness of the ligament. Percentages for areas of DRCT, fibrocartilage, degenerative tissue, and vasculature were calculated. Tissue composition and relative number of blood vessels were compared between groups. The proportion of DRCT to non-DRCT was significantly smaller in the OA group than the control group (p < .001); non-DRCT included degenerative connective tissue and fibrocartilage. The number of blood vessels to area was greater in the OA group than the control group (p = .002). Six of control (37.5%) and five of OA ACLs (83%) showed areas of calcification. These results indicate that inflammatory processes contributing to OA in the knee cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, calcification, and formation of fibrocartilage-like tissue inside the ligament. These changes make ligament-retaining total knee arthroplasty a less beneficial option for knee repair.

Anterior Cruciate Ligament Reconstruction in High School and College-Aged Athletes: Does Autograft Choice Influence Anterior Cruciate Ligament Revision Rates?

Background: Physicians’ and patients’ decision-making process between bone–patellar tendon–bone (BTB) and hamstring tendon autografts for anterior cruciate ligament (ACL) reconstruction (ACLR) may be influenced by a variety of factors in the young, active athlete. Purpose: To determine the incidence of both ACL graft revisions and contralateral ACL tears resulting in subsequent ACLR in a cohort of high school– and college-aged athletes who initially underwent primary ACLR with either a BTB or a hamstring autograft. Study Design: Cohort study; Level of evidence, 2. Methods: Study inclusion criteria were patients aged 14 to 22 years who were injured in sports, had a contralateral normal knee, and were scheduled to undergo unilateral primary ACLR with either a BTB or a hamstring autograft. All patients were prospectively followed for 6 years to determine whether any subsequent ACLR was performed in either knee after their initial ACLR. Multivariable regression modeling controlled for age, sex, ethnicity/race, body mass index, sport and competition level, baseline activity level, knee laxity, and graft type. The 6-year outcomes were the incidence of subsequent ACLR in either knee. Results: A total of 839 patients were eligible, of which 770 (92%) had 6-year follow-up for the primary outcome measure of the incidence of subsequent ACLR. The median age was 17 years, with 48% female, and the distribution of BTB and hamstring grafts was 492 (64%) and 278 (36%), respectively. The incidence of subsequent ACLR at 6 years was 9.2% in the ipsilateral knee, 11.2% in the contralateral normal knee, and 19.7% for either knee. High-grade preoperative knee laxity (odds ratio [OR], 2.4 [95% confidence interval [CI], 1.4-3.9]; P = .001), autograft type (OR, 2.1 [95% CI, 1.3-3.5]; P = .004), and age (OR, 0.8 [95% CI, 0.7-1.0]; P = .009) were the 3 most influential predictors of ACL graft revision in the ipsilateral knee. The odds of ACL graft revision were 2.1 times higher for patients receiving a hamstring autograft than patients receiving a BTB autograft (95% CI, 1.3-3.5; P = .004). No significant differences were found between autograft choices when looking at the incidence of subsequent ACLR in the contralateral knee. Conclusion: There was a high incidence of both ACL graft revisions and contralateral normal ACL tears resulting in subsequent ACLR in this young athletic cohort. The incidence of ACL graft revision at 6 years after index surgery was 2.1 times higher with a hamstring autograft compared with a BTB autograft.