Lever sign test for anterior cruciate ligament injuries: a diagnostic meta-analysis.

BACKGROUND: Sports-related ACL (anterior cruciate ligament) injuries are frequent. Successful management requires early diagnosis and treatment. One of the clinical tests used to identify ACL damage is the lever sign test. This meta-analysis aimed to assess the lever sign test's diagnostic efficacy for ACL injuries. METHODS: An extensive investigation of the Cochrane Library, Embase, and PubMed databases was conducted until April 2023. Studies assessing the lever sign test's diagnostic efficacy for ACL injuries were also included. A bivariate random-effects model was employed to acquire the pooled estimates of diagnostic odds ratios, specificity, positive and negative likelihood ratios, sensitivity, and curves of the summary receiver operating characteristic (SROC). RESULTS: The meta-analysis comprised twelve investigations with a total of 1365 individuals. The lever sign test's combined sensitivity and specificity for the purpose of diagnosing injuries to the ACL were 0.810 (95% confidence interval [CI] 0.686-0.893) and 0.784 (95% CI 0.583-0.904), respectively. The positive and negative likelihood ratios were 3.148 (95% CI 1.784-5.553) and 0.210 (95% CI 0.084-0.528), respectively. The study revealed a diagnostic odds ratio of 17.656, with a 95% CI ranging from 4.800 to 64.951. The SROC curve's area was determined to be 0.912 (95% CI 0.857-0.967). CONCLUSION: With high specificity and sensitivity, the lever sign test is a reliable diagnostic modality for ACL injuries. However, the test should be used in combination with other diagnostic tests to increase the accuracy of the diagnosis. Further investigations are warranted to assess the clinical practicability of the lever sign test in various populations and settings.

The relevance of knee arthroscopy photographs in medicolegal proceedings.

PURPOSE: Whether photographs included in the operative report of knee arthroscopies can make the surgeon liable in the event of a legal investigation remains unknown. The main objective of this study was to establish inter-observer reliability in determining the presence or absence of lesions of the cartilage, meniscus and anterior cruciate ligament (ACL). Secondary objective was to assess the inter-observer reliability in classifying lesions. METHOD: A retrospective observational study was conducted in a continuous serie of 60 patients who underwent knee arthroscopy from the same operator. The photographs of each patient's operative report were presented separately to three experts, blinded to each other. Each expert had to decide on the presence or absence of injuries to the following structures: meniscal, cartilage and ACL and then, classify it. Primary and secondary endpoints were evaluated using the Fleiss' kappa index. RESULTS: Inter-observer reliability for lesion detection was between 0.4 and 0.61 for all structures with three exceptions: for cartilage, it was low (0.15) at the lateral tibial plateau and poor (-0.01) at the external condyle. On the contrary, the concordance was almost perfect (0.8) for the ACL. For classifying cartilaginous and meniscal lesions, inter-observer reliability was poor (from 0.03 to 0.14), except for at the lateral meniscus (0.65). CONCLUSION: Inter-observer reliability of arthroscopic knee diagnoses is poor when photographs alone are used. In the event of a legal investigation following knee arthroscopy, the photographs included in the operative report should not be used alone to hold the surgeon liable.

Lever sign test shows high diagnostic accuracy for anterior cruciate ligament injuries: A systematic review and meta-analysis of 3299 observations.

PURPOSE: Injuries of the anterior cruciate ligament (ACL) are common knee injuries among active and younger patients. The Lever Sign Test (LST) is a relatively newer test, of which the accuracy is disputed in the existing literature. The aim of this study was to assess the accuracy with and without anesthesia of the Lever Sign test in the literature. METHODS: PRISMA guidelines were followed, studies were identified using PubMed, EMBASE and Google Scholar. All studies that reported accuracy of LST performed by a clinical professional were included. Integrity of ACL was confirmed using magnetic resonance imaging or arthroscopy. Sensitivity and specificity were calculated using uni- and bivariate methods. RESULTS: After inclusion, 3299 observations in 2516 patients were included from 23 studies. Mean age was 31.8 years and 64.2% were male. Without anesthesia, sensitivity was 79.2% (95% CI 68.7-86.9) and specificity was 92.0% (95% CI 82.2-96.6). An area under the curve (AUC) of 86.1% was found. With anesthesia, sensitivity was 86.6% (95% CI 68.0-95.2), specificity was 93.4% (95% CI 84.5-97.3) and the AUC was 91.6%. CONCLUSION: The Lever Sign test shows very good to excellent accuracy for ACL injury, and is a useful tool for clinical practice.

Medial meniscal lesions increase antero-posterior laxity in knees with anterior cruciate ligament injury.

PURPOSE: The aim of this study was to quantify the impact of concomitant meniscal lesions on knee laxity using a triaxial accelerometer in a large population of patients affected by anterior cruciate ligament (ACL) injury. METHODS: A total of 326 consecutive patients (261 men and 65 women, mean age 31.3 ± 11.3) undergoing primary ACL reconstruction, were preoperatively evaluated through Lachman and pivot shift tests using a triaxial accelerometer to quantify knee laxity. An analysis based on the presence of meniscal tears assessed during surgery was performed to evaluate the impact of meniscal lesions on knee laxity. RESULTS: The anterior tibial translation (Lachman test) presented significantly higher values in patients with medial meniscal lesions (7.3 ± 1.7 mm, p = 0.049) and both medial and lateral meniscal lesions (7.7 ± 1.6 mm, p = 0.001) compared to patients without concomitant meniscal lesions (6.7 ± 1.3 mm). Moreover, patients with both medial and lateral meniscal lesions presented significantly higher values of anterior tibial translation compared to patients with lateral meniscal lesions (p = 0.049). No statistically significant differences were found between the groups in terms of tibial acceleration (pivot shift test). CONCLUSION: This study demonstrated that the contribution of concomitant meniscal lesions to knee laxity can be objectively quantified using a triaxial accelerometer in ACL-injured knees. In particular, medial meniscus lesions, alone or in association with lateral meniscus lesions, determine a significant increase of the anterior tibial translation compared to knees without meniscus tears. LEVEL OF EVIDENCE: Level IV.

Incidence of and Risk Factors for Arthrogenic Muscle Inhibition in Acute Anterior Cruciate Ligament Injuries: A Cross-Sectional Study and Analysis of Associated Factors From the SANTI Study Group.

BACKGROUND: Arthrogenic muscle inhibition (AMI) is a process in which neural inhibition after injury or surgery to the knee results in quadriceps activation failure and knee extension deficit. PURPOSE: To determine the incidence and spectrum of the severity of AMI after acute anterior cruciate ligament (ACL) injury using the Sonnery-Cottet classification, to determine the interobserver reliability of the classification system, and to investigate potential important factors associated with AMI after ACL injury. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Consecutive patients who had an acute ACL injury between October 2021 and February 2022 were considered for study inclusion. Eligible patients underwent a standardized physical examination at their first outpatient appointment. This included an assessment of quadriceps inhibition, identification of any extension deficits, and grading of AMI and its reversibility according to the Sonnery-Cottet classification. RESULTS: A total of 300 consecutive patients with acute ACL ruptures were prospectively enrolled in the study. Of them, 170 patients (56.7%) had AMI. Patients evaluated with AMI showed a significantly inferior Lysholm score, International Knee Documentation Committee score, Simple Knee Value, and Knee injury and Osteoarthritis Outcome Score than patients without AMI (P < .0001). Multivariate analysis revealed that the presence of effusion, concomitant injuries, and high pain scores were associated with a significantly greater risk of AMI. Additional associations with the presence of AMI included a short duration between injury and evaluation, the use of crutches, and using a pillow as a support at night. In contrast, a previous ACL injury was associated with significantly lower odds of developing AMI (OR, 0.025; 95% CI, 0-0.2; P = .014). Among the 170 patients with AMI, 135 patients (79%) showed a resolution of their inhibition at the end of the consultation after application of simple exercises; the remaining 35 patients required specific rehabilitation. Interobserver reliability of the classification system was almost perfect (95% CI, 0.86-0.99). CONCLUSION: AMI occurs in over half of patients with acute ACL injuries. When it occurs, it is easily reversible in the majority of patients with simple exercises targeted at abolishing AMI. The presence of "red flags" should increase the index of suspicion for the presence of AMI, and these include the presence of an effusion, high pain scores, a short time between injury and evaluation, multiligament injuries, the use of crutches, and using a pillow as a support at night. Patients with a history of ipsilateral or contralateral ACL injury are at a significantly lower risk of AMI than those with a first-time ACL injury.

Development and Operationalization of an Automated Workflow for Correlation of Knee MRI and Arthroscopy Findings.

OBJECTIVE: In this study, we sought to establish and evaluate an automated workflow to prospectively capture and correlate knee MRI findings with surgical findings in a large medical center. METHODS: This retrospective analysis included data from patients who had undergone knee MRI followed by arthroscopic knee surgery within 6 months during a 2-year period (2019-2020). Discrete data were automatically extracted from a structured knee MRI report template implementing pick lists. Operative findings were recorded discretely by surgeons using a custom-built web-based telephone application. MRI findings were classified as true-positive, true-negative, false-positive, or false-negative for medial meniscus (MM), lateral meniscus (LM), and anterior cruciate ligament (ACL) tears, with arthroscopy used as the reference standard. An automated dashboard displaying up-to-date concordance and individual and group accuracy was enabled for each radiologist. Manual correlation between MRI and operative reports was performed on a random sample of 10% of cases for comparison with automatically derived values. RESULTS: Data from 3,187 patients (1,669 male; mean age, 47 years) were analyzed. Automatic correlation was available for 60% of cases, with an overall MRI diagnostic accuracy of 93% (MM, 92%; LM, 89%; ACL, 98%). In cases reviewed manually, the number of cases that could be correlated with surgery was higher (84%). Concordance between automated and manual review was 99% when both were available (MM, 98%; LM, 100%; ACL, 99%). CONCLUSION: This automated system was able to accurately and continuously assess correlation between imaging and operative findings for a large number of MRI examinations.

[Reliability and validity of the Lever Sign Test in suspected ligament and/or meniscus injuries of the knee: a comparison between an orthopaedist and a physical therapist]. / Reliabilität und Validität des Lever Sign Tests bei Verdacht auf Band- und/oder Meniskus-Verletzung des Knies: ein Vergleich zwischen Orthopäde und Physiotherapeut.

INTRODUCTION: The purpose of this study was to investigate the intertester reliability and validity of the Lever Sign Test. Intertester reliability has received little attention in previous studies. In order to make comparisons with other studies, the intertester reliability and validity of the Lachman and Anterior Drawer Tests were also calculated. PATIENTS/MATERIAL AND METHODS: Patients between 18 and 50 years of age with suspected ligament and/or meniscus injuries were included. Exclusion criteria were suspected malignant, systemic, or central neurologic disease, acute cartilage injury, suspected fracture, or knowledge of the participant's knee findings. Testing was randomized and blinded by an experienced orthopaedic surgeon and a physical therapist. Cohen's kappa was calculated for intertester reliability. Sensitivity and specificity, positive and negative predictive value, and positive and negative likelihood ratio were calculated. MRI findings were used as the gold standard. RESULTS: Thirty-six patients were enrolled in the study, 27 male (75%) and 9 female (25%). The prevalence of anterior cruciate ligament lesions was 44.4%. Cohen's kappa (κ) was κ=0.6 (CI 95% [0.29, 0.91]) for the Lever Sign Test, κ=0.64 (CI 95% [0.35, 0.93]) for the Lachman test, and κ=0.63 (CI 95% [0.3, 0.95]) for the Anterior Drawer Test. The sensitivity of the Lever Sign Test was 0.53 and 0.40 for the orthopaedic surgeon and physical therapist, respectively, specificity was 0.89 and 0.79, the positive predictive value was 0.80 and 0.60, the negative predictive value was 0.70 and 0.62, the positive likelihood ratio was 4.80 and 1.90, respectively, and the negative likelihood ratio was 0.76 and 0.53. CONCLUSION: The estimated intertester reliability of the Lever Sign Test was good. The Lever Sign Test is suitable as a complement to the Lachman Test, which is considered the most valid test in the literature. The weaknesses and ambiguities of the operating mechanism of the Lever Sign Test should not be ignored and should be further explored.

Long-Term Outcomes of Primary Anterior Cruciate Ligament Reconstruction Using Achilles Tendon Allograft.

PURPOSE: This study sought to assess the long-term structural integrity of primary anterior cruciate ligament (ACL) reconstructions using Achilles tendon allografts by measuring the side-to-side difference in anterior-posterior tibial translation between the operative knee and the contralateral, asymptomatic knee. METHODS: This study was a retrospective case series consisting of patients who underwent primary ACL reconstruction with Achilles tendon allograft. Allografts were chemically processed using the AlloWash or AlloTrue methods and then received either gamma radiation or electron beam radiation (range: 0.95 to 1.4 Mrad dose). At the time of follow-up, anterior-posterior tibial translation of both the operative and contralateral knees was measured using the Lachmeter® device. Functional outcomes were assessed using the International Knee Documentation Committee (IKDC) questionnaire and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. RESULTS: The analysis included 20 patients (mean age: 41.38 ± 14.27 years) with a mean follow-up time of 7.01 ± 5.24 years. There were no graft failures requiring revision during the study period. The mean side-to-side difference in laxity between operative and contralateral knees was 1.10 ± 2.02 mm. Two patients (10%) met the criteria for complete ACL injury at the time of follow-up, while the remaining 18 patients (90%) met the criteria for no ACL injury. The mean IKDC score was 83.5 ± 13.8, and mean KOOS score was 88.4 ± 10.7. CONCLUSIONS: Primary ACL reconstruction using an Achilles tendon allograft in skeletally mature patients resulted in maintained knee stability and good functional outcomes over the long-term postoperative period.

Effects of proprioceptive training on gait and plantar pressure after anterior cruciate ligament reconstruction: study protocol for a randomized controlled trial.

BACKGROUND: People who have undergone anterior cruciate ligament reconstruction have an increased risk of osteoarthritis. Abnormality of lower limb kinematics will occur after the operation. This may be related to lower limb muscle strength, the co-excitation of hamstrings and quadriceps femoris, and the weakness of proprioception. Proprioceptive training can improve the proprioception of lower limbs and promote the recovery of lower limb kinematics. Our research objective is to observe whether proprioceptive training can improve the proprioception of lower limbs within 3 months after surgery and whether the recovery of proprioception can correct the abnormal lower limb kinematics. The secondary objective is to explore the underlying mechanism of postoperative lower limb gait abnormalities. METHODS/DESIGN: This study is a prospective single-center randomized clinical trial to be conducted in the Sports Medicine and Orthopedics of Zhongda Hospital Southeast University. Forty participants aged 18-50, preparing to undergo anterior cruciate ligament reconstruction, and initial anterior cruciate ligament reconstruction using hamstring tendons as grafts will be randomly assigned to the intervention or comparator group. People in the intervention group will add proprioceptive training three times a week, 20 min each time. The intervention will be conducted on the first day after surgery. The researcher mainly collects the data of joint of sense, gait, and plantar pressure. The assessment will be divided into three stages: after signing the informed consent form (within 2 weeks before surgery), 6 weeks after surgery, and 12 weeks after surgery. DISCUSSION: The main purpose of our study is to explore whether the proprioception of patients after anterior cruciate ligament reconstruction is weakened, whether the lower limb kinematics is abnormal and whether the lower limb kinematics can be corrected through proprioceptive training. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2200065808. Registered on 15 November 2022; Version 1.

Functional performance tests, clinical measurements, and patient-reported outcome measures do not correlate as outcomes 1 year after anterior cruciate ligament reconstruction.

PURPOSE: The results after anterior cruciate ligament reconstruction (ACLR) are evaluated by laxity measures, functional tests, and patients' perception by patient-reported outcome measures (PROMs). It is not known, if one of these evaluation instruments is representative or if outcome scores from all must be reported to obtain a full evaluation of the condition. The aim was to study the correlations between these three types of outcomes 1 year after primary ACLR. METHOD: All adult patients (range 18-45 years) who had an ACLR between 1.1.2019 and 31.12.2021 were offered 1-year follow-up by an independent observer. Preoperative information about knee laxity and peroperative information about the condition of menisci and cartilage were registered. At 1-year follow-up clinical and instrumented knee stability and function assessed by four different hop tests were registered. Patients completed four PROMs (the Subjective International Knee Documentation Committee (IKDC) score, the Knee Numeric-Entity Evaluation Score (KNEES-ACL), the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Lysholm score) and Tegner activity scale and answered anchor questions regarding satisfaction and willingness to repeat the operation. RESULTS: A total of 190 adults attended the 1-year follow-up and 151 had all assessments. There were only a few positive and weak correlations between performance tests and PROMS and between clinical measurements and PROMS (r = 0.00-0.38), and the majority were of negligible strength. Tegner score had in general the highest correlation (low to moderate). The highest correlation was 0.53 (moderate) between the anchor question about patient satisfaction and Lysholm/IKDC scores. There was no difference in the correlations depending on meniscal condition. CONCLUSIONS: In ACLR patients there was no clinically relevant correlation between scores obtained by PROMs, a battery of functional performance tests and instrumented laxity of the knee at 1-year follow-up. Therefore, one type of outcome cannot represent the others. This is an argument for always to include and report all three types of outcomes, and conclusions based on one type of outcome may not be sufficient. LEVEL OF EVIDENCE: II.

Rupture of Anterior Cruciate Ligaments and the Lever Test in Diagnosis: A Critical Review.

Anterior Cruciate Ligament (ACL) rupture is known to be one of the most common musculoskeletal injuries in active individuals especially athletes. Approximately 200.000 ACL injuries occur every year of which 100,000 require surgery. Once ruptured, it becomes very difficult to regain its previous function and it does not have the capacity to heal on its own. It is thus very important to diagnose an ACL rupture as early as possible. Clinicians thus need to perform a test which has a high sensitivity to rule out a negative test and specificity in order to rule in a positive test in the diagnosis. In this review four different tests (Lever Sign Test, Lachman test, Anterior drawer test and Pivot Shift Test) are compared among each other to find out the better option among the selected tests.

A Web-Based Prediction Tool to Improve Identification of Patients With Undersized Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction.

BACKGROUND: An undersized hamstring tendon (HT) autograft is significantly associated with a higher graft failure rate in anterior cruciate ligament reconstruction (ACLR) surgery. The ability to accurately predict inadequate HT graft diameter is critical, as it could assist surgeons in making better graft choices and surgical plans. PURPOSE: To develop a web-based prediction tool to better assess the size of HT autograft and to help clinicians accurately identify patients with potentially undersized HT grafts in order to make appropriate clinical decisions. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 588 patients who received primary arthroscopic single-bundle ACLR surgery with gracilis tendon (GT) and semitendinosus tendon (ST) autograft were retrospectively reviewed. According to the size of 4-strand HT graft, patients were divided into diameter ≥8 mm and <8 mm groups. The least absolute shrinkage and selection operator method and logistic regression were used to identify the independent factors associated with HT graft diameter and establish the models. The prediction performance of the model was evaluated by concordance index and calibration combined with external validation. The diagnostic performance of the prediction model was assessed by sensitivity, specificity, predictive values, and likelihood ratios. Decision curve analysis was used to evaluate the clinical utility of the model. RESULTS: Among the numerous indicators, sex, weight, height, thigh length, and ST-GT diameter (measured on plane 1 of a magnetic resonance imaging scan) were identified to be highly correlated predictors that could provide satisfactory prediction performance in determining the HT graft diameter. Based on these predictors, a prediction model named the HTD model was developed with satisfactory discrimination (concordance index, 0.932) and calibration (mean absolute error, 0.039). When the probability calculated by the HTD model was >65%, the sensitivity and specificity of predicting 4-strand HT graft diameter ≥8 mm were 86.7% and 90.2%, respectively. CONCLUSION: As a useful supplementary prediction tool, the HTD model could accurately predict the diameter of HT autograft during preoperative planning.

Management of anterior cruciate ligament revision in adults: the 2022 ESSKA consensus: part II-surgical strategy.

PURPOSE: The aim of this ESSKA consensus is to give recommendations based on scientific evidence and expert opinion to improve the diagnosis, preoperative planning, indication and surgical strategy in Anterior Cruciate Ligament revision. METHODS: Part 2, presented herein, followed exactly the same methodology as Part 1: the so-called ESSKA formal consensus derived from the Delphi method. Eighteen questions were ultimately asked. The quality of the answers received the following grades of recommendation: Grade A (high level scientific support), Grade B (scientific presumption), Grade C (low level scientific support) or Grade D (expert opinion). All answers were scored from 1 to 9 by the raters. Once a general consensus had been reached between the steering and rating groups, the question-answer sets were submitted to the peer-review group. A final combined meeting of all the members of the consensus was then held to ratify the document. RESULTS: The review of the literature revealed a rather low scientific quality of studies examining the surgical strategy in cases of ACL reconstruction failure. Of the 18 questions, only 1 received a Grade A rating; 5, a Grade B rating; and 9, grades of C or D. The three remaining complex questions received further evaluations for each portion of the question and were looked at in more detail for the following grades: B and D; A, C and D; or A, B, C and D. The mean rating of all questions by the rating group was 8.0 + - 1.1. The questions and recommendations are listed in the article. CONCLUSION: ACL revision surgery, especially the surgical strategy, is a widely debated subject with many different opinions and techniques. The literature reveals a poor level of standardization. Therefore, this international European consensus project is of great importance and clinical relevance for guiding the management of ACL revision in adults. LEVEL OF EVIDENCE: Level II.

Validation of the ACL-RSI Scale in Pediatric and Adolescent Patients.

BACKGROUND: The Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI) scale is a 12-item questionnaire assessing psychological readiness to return to sport after anterior cruciate ligament reconstruction. It has been validated for use in adults in multiple languages and in an abbreviated 6-question short form. Additionally, literature has been published using this scale in pediatric and adolescent populations, however it has not yet been validated for use with them. PURPOSE: To validate the ACL-RSI scale for use with pediatric and adolescent patients. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: Scores of 6- and 12-item ACL-RSI scales for patients undergoing return-to-sport readiness testing 6 to 8 months after anterior cruciate ligament reconstruction were analyzed. Convergent validity testing was performed against the International Knee Documentation Committee (IKDC)/Pediatric IKDC score, Single Assessment Numeric Evaluation (SANE) score, and peak torque asymmetry of knee flexion and extension using Spearman correlations. Discriminant validity testing was performed against age (Spearman correlation), body mass index (Spearman correlation), and sex (Mann-Whitney U test). Reliability testing was performed by calculating Cronbach's alpha. Floor and ceiling effects were assessed by calculating the number of minimum and maximum scores in the cohort. RESULTS: A total of 51 patients were included in the final analysis. The mean age at surgery was 15.2 ± 2.2 years, and 51.0% were female. The 6- and 12-item ACL-RSI scales demonstrated a strong significant positive correlation with IKDC/Pediatric IKDC scores (R = 0.723 and 0.717, respectively; P < .001) and moderate significant positive correlation with Single Assessment Numeric Evaluation scores (R = 0.516 and 0.502, respectively; P < .001) Age at surgery, body mass index, and sex were not correlated with either ACL-RSI scale. Cronbach's alpha values of the 12- and 6-item ACL-RSI scales in this population were 0.959 and 0.897, respectively. For both the 12- and the 6-item ACL-RSI scales, no floor or ceiling effects were found as the minimum score (0) was not observed in either version, and the maximum score (100) was only observed twice (3.9%) in both versions. CONCLUSION: The ACL-RSI scale is valid to use with pediatric and adolescent patients. The 6-item scale may be a better choice because it has fewer redundancies and minimizes the risk of questionnaire fatigue.

Digital measurement of anterolateral knee laxity using strain sensors.

PURPOSE: The ambition of the research group was to develop a sensor-based system that allowed the transfer of results with strain sensors applied to the knee joint. This system was to be validated in comparison to the current static mechanical measurement system. For this purpose, the internal rotation laxity of the knee joint was measured, as it is relevant for anterolateral knee laxity and anterior cruciate ligament (ACL) injury. METHODS: This is a noninvasive measurement method using strain sensors which are applied to the skin in the course of the anterolateral ligament. The subjects were placed in supine position. First the left and then the right leg were clinically examined sequentially and documented by means of an examination form. 11 subjects aged 21 to 45 years, 5 women and 6 men were examined. Internal rotation of the lower leg was performed with a torque of 2 Nm at a knee flexion angle of 30°. RESULTS: Comparison of correlation between length change and internal knee rotation angle showed a strong positive correlation (r = 1, p < 0.01). Whereas females showed a significant higher laxity vs. males (p = 0.003). CONCLUSIONS: The present study showed that the capacitive strain sensors can be used for reproducible measurement of anterolateral knee laxity. In contrast to the previous static systems, a dynamic measurement will be possible by this method in the future.

BLU-DAT: a new reliable and accurate arthrometer for measuring anterior knee laxity.

PURPOSE: Although many arthrometers have been developed to assess anterior knee laxity, reliability and diagnostic accuracy of these devices are still debated. The aim of the present study was to evaluate the validity of a new arthrometer in the outpatient setting, with the hypothesis that it had good validity in terms of reliability and diagnostic accuracy. METHODS: Seventy-eight subjects (39 with ACL injury and 39 with normal ACL) were tested. ATT was assessed by means of the Lachman test at 30° of flexion with a new testing device (BLU-DAT) under three different loading conditions: 7 kg (69 N), 9 kg (88 N) and maximum (MMT). The tests were performed on both knees to obtain SSD. In the ACL injury group, the tests were performed by two examiners and one of them repeated a second test series. Inter- and intra-observer reliability were assessed with the intraclass correlation coefficients (ICCs) for the average SSD measures. In the normal-ACL group, the analysis was performed with the same testing setup. Side-to-side difference measures of the two groups at every loading condition were compared by Student's t test. Data of test series were dichotomized based on the threshold value of 3-mm SSD as pathological ATT and 2 × 2 contingency tables were used to assess diagnostic accuracy. RESULTS: The ICCs for intra-observer reliability at 7-kg (69 N), 9-kg (88 N) and MMT measurements were 0.781, 0.855 and 0.913, respectively. The ICC for inter-observer reliability at 7-kg (69 N), 9-kg (88 N) and MMT measurements were 0.701, 0.845 and 0.834, respectively. Comparison between the two groups showed a significant mean difference ranging from 3.4 mm for 7-kg (69 N) load to 4.6 mm for MMT. Overall accuracy ranged from 84.6% for 7-kg load to 98.7% for MMT. CONCLUSION: The BLU-DAT has proven to be an instrument with good intra- and inter-observer reliability and very good accuracy in the diagnosis of ACL injuries in the outpatient setting. So, the BLU-DAT can be a new useful tool in everyday clinical practice to assist in the diagnosis of ACL injury. LEVEL OF EVIDENCE: II.

Machine learning can accurately predict risk factors for all-cause reoperation after ACLR: creating a clinical tool to improve patient counseling and outcomes.

PURPOSE: Identifying predictive factors for all-cause reoperation after anterior cruciate ligament reconstruction could inform clinical decision making and improve risk mitigation. The primary purposes of this study are to (1) determine the incidence of all-cause reoperation after anterior cruciate ligament reconstruction, (2) identify predictors of reoperation after anterior cruciate ligament reconstruction using machine learning methodology, and (3) compare the predictive capacity of the machine learning methods to that of traditional logistic regression. METHODS: A longitudinal geographical database was utilized to identify patients with a diagnosis of new anterior cruciate ligament injury. Eight machine learning models were appraised on their ability to predict all-cause reoperation after anterior cruciate ligament reconstruction. Model performance was evaluated via area under the receiver operating characteristics curve. To explore modeling interpretability and radiomic feature influence on the predictions, we utilized a game-theory-based method through SHapley Additive exPlanations. RESULTS: A total of 1400 patients underwent anterior cruciate ligament reconstruction with a mean postoperative follow-up of 9 years. Two-hundred and eighteen (16%) patients experienced a reoperation after anterior cruciate ligament reconstruction, of which 6% of these were revision ACL reconstruction. SHapley Additive exPlanations plots identified the following risk factors as predictive for all-cause reoperation: diagnosis of systemic inflammatory disease, distal tear location, concomitant medial collateral ligament repair, higher visual analog scale pain score prior to surgery, hamstring autograft, tibial fixation via radial expansion device, younger age at initial injury, and concomitant meniscal repair. Pertinent negatives, when compared to previous studies, included sex and timing of surgery. XGBoost was the best-performing model (area under the receiver operating characteristics curve of 0.77) and outperformed logistic regression in this regard. CONCLUSIONS: All-cause reoperation after anterior cruciate ligament reconstruction occurred at a rate of 16%. Machine learning models outperformed traditional statistics and identified diagnosis of systemic inflammatory disease, distal tear location, concomitant medial collateral ligament repair, higher visual analog scale pain score prior to surgery, hamstring autograft, tibial fixation via radial expansion device, younger age at initial injury, and concomitant meniscal repair as predictive risk factors for reoperation. Pertinent negatives, when compared to previous studies, included sex and timing of surgery. These models will allow surgeons to tabulate individualized risk for future reoperation for patients undergoing anterior cruciate ligament reconstruction. LEVEL OF EVIDENCE: III.

Evaluation of the accuracy and intra- and interobserver reliability of three manual laxity tests for canine cranial cruciate ligament rupture-An ex vivo kinetic and kinematic study.

OBJECTIVES: To investigate the accuracy and intra- and interobserver reliability of the cranial drawer test (CD), tibial compression test (TCT), and the new tibial pivot compression test (TPCT) in an experimental setting resembling acute cranial cruciate ligament rupture (CCLR) and to elucidate the ability to subjectively estimate cranial tibial translation (CTT) during testing. STUDY DESIGN: Experimental ex vivo study. SAMPLE POPULATION: Ten cadaveric hindlimbs of large dogs. METHODS: Kinetic and 3D-kinematic data was collected while three observers performed the tests on each specimen with intact (INTACT) and transected cranial cruciate ligament (CCLD) and compared using three-way repeated-measures ANOVA. Subjectively estimated CTT (SCTT), obtained during a separate round of testing, was compared to kinematic data by Pearson correlation. RESULTS: CTT was significantly higher for CCLD than for INTACT for all tests, resulting in 100% sensitivity and specificity. TPCT induced the highest CTT and internal rotation. Intra- and interobserver agreement of translation was excellent. For rotation and kinetics, agreement was more variable. SCTT strongly correlated with the objectively measured values. CONCLUSION: The CD, TCT and the new TPCT were all accurate and reliable. The high translations and rotations during TPCT are promising, encouraging further development of this test. SCTT was reliable in our experimental setting. CLINICAL SIGNIFICANCE: Veterinary manual laxity tests are accurate and reliable in acute CCLR. The TPCT might have potential for the assessment of subtle and rotational canine stifle instabilities. The high reliability of SCTT implies that grading schemes for stifle laxity, similar to human medicine, could be developed.

The posterior cruciate ligament index as a reliable indirect sign of anterior cruciate ligament rupture is associated with the course of knee joint injury.

PURPOSE: The objective of this study was to clarify the clinical value of the posterior cruciate ligament index (PCLI) in anterior cruciate ligament (ACL) rupture, to explore the relationship between the PCLI and course of disease, and to identify the influencing factors of the PCLI. METHODS: The PCLI was defined a quotient of the X (the tibial and femoral PCL attachments) and the Y (the maximum perpendicular distance from X to the PCL). A total of 858 patients were enrolled in this case-control study, including 433 patients with ACL ruptures who were assigned to the experimental group and 425 patients with meniscal tears (MTs) who were allocated to the control group. Some patients in the experimental group have collateral ligament rupture (CLR). Information, such as the patient's age, sex, and course of disease, was recorded. All patients underwent magnetic resonance imaging (MRI) preoperatively, and the diagnosis was confirmed with the aid of arthroscopy. The PCLI and the depth of the lateral femoral notch sign (LFNS) were calculated based on the MRI findings, and the characteristics of the PCLI were explored. RESULTS: The PCLI in the experimental group (5.1 ± 1.6) was significantly smaller than that in the control group (5.8 ± 1.6) (P < 0.05). The PCLI gradually decreased with time and was only 4.8 ± 1.4 in patients in the chronic phase (P < 0.05). This change was not due to the decrease in X but rather the increase in Y. The results also showed that the PCLI was not related to the depth of the LFNS or injuries of other structures in the knee joint. Furthermore, when the optimal cut-off point of the PCLI was 5.2 (area under the curve = 71%), the specificity and the sensitivity were 84% and 67%, respectively, but the Youden index was just 0.3 (P < 0.05). CONCLUSION: The PCLI decreases due to the increase in Y instead of the decrease in X with time, especially in the chronic phase. The change in X in this process may be offset during imaging. In addition, there are fewer influencing factors that lead to changes in the PCLI. Therefore, it can be used as a reliable indirect sign of ACL rupture. However, it is difficult to quantify the diagnostic criteria of the PCLI in clinical practice. Thus, the PCLI as a reliable indirect sign of ACL rupture is associated with the course of knee joint injury, and it can be used to describe the instability of the knee joint. LEVELS OF EVIDENCE: III.