Anterior Cruciate Ligament Status Research Articles

Factors influencing the posterior cruciate ligament buckling phenomenon—a multiple linear regression analysis of bony and soft tissue structures of the knee joint

PurposeTo determine whether posterior cruciate ligament (PCL) buckling (angular change) is associated with anterior cruciate ligament (ACL) status (intact or ruptured), meniscal bone angle (MBA), anterior tibial translation (ATT), body weight, femoral-tibial rotation (FTR), posterior tibial slope (PTS), PCL length and femoral-tibial distance (FTD) and to identify the factors that have the greatest influence.MethodsAll enrolled participants were scanned with a 3.0 T, 8-channel coil MRI system (Magnetom Verio; Siemens). Bone and soft tissue parameters were measured by MIMICS software for each subject and each measured parameter was correlated with PCL buckling phenomena. The correlated and statistically significant parameters were then analyzed by multiple linear regression to determine the magnitude of the effect of the different parameters on the PCL buckling phenomenon.ResultsA total of 116 subjects (50 ACL ruptured and 66 age, weight and height matched volunteers with uninjured knees) were enrolled. Among all measured parameters, there were 8 parameters that correlated with PCL angle (PCLA), of which ACL status had the strongest correlation with PCLA (r = − 0.67, p = < 0.001); and 7 parameters that correlated with PCL-posterior femoral cortex angle (PCL-PCA), of which ATT had the strongest correlation with PCL-PCA (r = 0.69, p = < 0.001). PCLIA was not significantly correlated with any of the measured parameters. Multiple linear regression analyses revealed four parameters can explain PCLA, of which ACL status had the strongest effect on PCLA (absolute value of standardized coefficient Beta was 0.508). Three parameters can explain PCL-PCA, of which ATT had the strongest effect on PCLIA (r = 0.69, p = < 0.001), ATT has the greatest effect on PCL-PCA (absolute value of normalized coefficient Beta is 0.523).ConclusionsPCLA may be a simple and easily reproducible and important supplement for the diagnosis of ACL injury; PCL-PCA is a simple and easily reproducible and important complementary tool for the detection of ATT. The use of PCLA is more recommended to aid in the diagnosis of ACL injury.

The Impact of Different Anterior Cruciate Ligament Status on Unicompartmental Knee Arthroplasty: Short Term Clinical and Functional Results

Purpose: Purpose of this study is to compare the short-term results of unicompartmental knee arthroplasty applied stable knees regardless of the condition of the ACL and the application of unicompartmental knee arthroplasty and ACL reconstruction combined surgery applied to ACL deficient cases with anterior instability and to identify the condition and function of the ACL for success in this surgery. Patients and Methods: 80 out of the 105 patients who were operated in 2013-2015 and came for follow-up were included in the study and the patients were divided into four groups. The VAS pain score, KSS Score, WOMAC score, OKS questionnaires and joint range of motion measurements were conducted pre-operatively and post-operatively. One leg standing test, joint position sense measurement, and isokinetic muscle strength test were performed in post-operative controls. Results: There was no statistically significant difference between the demographic data and follow-up of the groups (p˃0.05). While there was a statistically significant difference in knee flexion between Group 2-Group 4 and Group 3-Group 4 in the pre-operative period, no difference was found in the post-operative period (p˃0.05). While there was no difference among the groups, knee joint range of motion in direction of extension declined in a statistically significant way in all four groups (p˂0.05). Pain felt postoperatively was the most in Group 1 and the least in Group 3. A statistically significant difference was found between Group 1 and Group 3 in the test performed with the eyes closed (p˂0.05). Conclusion: The presence of a functional anterior cruciate ligament is expected to make a positive contribution to surgical results especially in young patients with high activity expectation. Whether the patient’s ACL rupture is primary or secondary and his/her activity expectation should be effective in the choice of a surgical method.

Approaching expert-level accuracy for differentiating ACL tear types on MRI with deep learning

Treatment for anterior cruciate ligament (ACL) tears depends on the condition of the ligament. We aimed to identify different tear statuses from preoperative MRI using deep learning-based radiomics with sex and age. We reviewed 862 patients with preoperative MRI scans reflecting ACL status from Hunan Provincial People’s Hospital. Based on sagittal proton density-weighted images, a fully automated approach was developed that consisted of a deep learning model for segmenting ACL tissue (ACL-DNet) and a deep learning-based recognizer for ligament status classification (ACL-SNet). The efficacy of the proposed approach was evaluated by using the sensitivity, specificity and area under the receiver operating characteristic curve (AUC) and compared with that of a group of three orthopedists in the holdout test set. The ACL-DNet model yielded a Dice coefficient of 98% ± 6% on the MRI datasets. Our proposed classification model yielded a sensitivity of 97% and a specificity of 97%. In comparison, the sensitivity of alternative models ranged from 84 to 90%, while the specificity was between 86 and 92%. The AUC of the ACL-SNet model was 99%, demonstrating high overall diagnostic accuracy. The diagnostic performance of the clinical experts as reflected in the AUC was 96%, 92% and 88%, respectively. The fully automated model shows potential as a highly reliable and reproducible tool that allows orthopedists to noninvasively identify the ACL status and may aid in optimizing different techniques, such as ACL remnant preservation, for ACL reconstruction.

Vertical Stenosis as a Morphological Risk Factor for Anterior Cruciate Ligament Ruptures in Children: A Magnetic Resonance Imaging–Based Comparison

Background: There are known anatomic variations that may lead to traumatic disruption of the anterior cruciate ligament (ACL) identified within adult and adolescent patients. Purpose/Hypothesis: The purpose of this study was to compare the parameters of pediatric knees diagnosed with and without an ACL injury by magnetic resonance imaging. The hypothesis was that children with ACL abnormalities would demonstrate an equivalent notch width index (NWI), but a larger notch height index (NHI), in comparison with age-matched patients without ACL abnormalities, suggesting an association with congenital morphology. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective comparison cohort study of pediatric knees was performed by evaluating those with a confirmed ACL rupture/deficiency and those with a benign diagnosis on magnetic resonance imaging. Overall, 6 osseous and cartilaginous measurements and 3 ratios (2 newly described) were determined. They were then grouped for statistical purposes by age: children aged 5 to 11 years and adolescents aged 12 to 19 years. Results: A total of 119 (49 children) consecutive patients with an ACL injury and 139 (72 children) healthy patients met inclusion criteria. The interaction between ACL status and age was significant for condylar measurements (P≤ .001), tibial spine height (P = .003), vertical space above tibial spine (P≤ .001), and NWI (P≤ .001) by 2-way analysis of variance. Although the NHI (P < 0.001) and tibial spine prominence (P = 0.039) demonstrated stenosis in the adolescent group, they did not have significant interactions with age and ACL status (P > 0.05). Regarding the transcondylar width, only the children's group had a significant difference regarding ACL status (P < .001), and the mean values in the children's group with ACL tears were nearly identical to those in the adolescent group both with and without ACL tears. The children's group with ACL tears also had a significantly larger tibial spine height compared with healthy children (P < .001). Conclusion: Children, similar to adolescents, demonstrated the effect of the NWI on the risk of ACL tears, but only the adolescent group demonstrated stenosis with the NHI. The morphology of the knee in a child at risk for ACL rupture was not the same as that of an adolescent when considering all dimensions, but it did seem that it was more adolescent-like than child-like at the time of an ACL rupture, refuting the idea of congenital hypoplasia as a common cause.

Correlation between spatial inclination of Blumensaat line and anterior cruciate ligament injury based on EOS biplanar 3D imaging system

To explore correlation between femoral mechanical axis and Blumensaat line (FMBL) angle of knee joint (angle between Blumensaat line and femoral mechanical axis), α angle (angle between Blumensaat line and axis of distal femur in sagittal plane) on EOS biplane imaging and non-contact anterior cruciate ligament(ACL) injury, and evaluate angle for its accuracy in predicting the populations prone to non-contact ACL injury. From February 2018 to October 2020, EOS imaging and clinical data from 88 patients (176 knees) with unilateral non-contact ACL injury were retrospectively analyzed, including 53 males and 35 females, aged from 18 to 45 years old with an average of (30.3±6.2) years old, 48 patients on the left side and 40 patients on the right side. The patients were divided into ACL-affected group and ACL-health group according to side of ACL injuries, and 51 patients (51 knees) with non-ACL identified from EOS database were included in normal control group, including 28 males and 23 females, aged from 20 to 44 years old with an average of (31.6±5.5) years old, 26 patients on the left side and 25 patients on the right side. Full-length EOS imaging of skeleton extremitatis inferioris among three groups were reconstructed to 3D images of skeletal system with EOS software, and then FMBL angle and α angle were measured on the images. Univariate binary Logistic regression analysis was performed to determine the influence of the univariate(FMBL angle or α angle) on ACL status(normal or torn). And the angle cutoff value for univariate was selected based on receiver operating characteristics curve (ROC) to got the best accuracy. There was no statistically significant difference in age, gender and side distribution between ACL-injured group and normal control group(P>0.05). Statistical analyses (one-way ANOVA) indicated no significant difference in FMBL angle between ACL-injured knee group (32.8±2.3)° and ACL-injured contralateral knee group(32.5±2.3)°(P>0.05), but the values between two groups were significantly lower than that in normal control group (37.0±2.0)°(P<0.001). There was no statistically significant difference in α angle among three groups (P>0.05). Univariate binary Logistic regression analysis demonstrated that FMBL angle was risk factor for non-contact ACL injury[OR=0.433, 95%CI(0.330, 0.569), P<0.001]. The area under ROC curve for FMBL angle was 0.909[95%CI(0.861, 0.958), P<0.001], and the sensitivity and specificity were 70.5% and 98.0% respectively, cut-off value was 33.7°. FMBL angle formed by Blumensaat line and femoral mechanical axis is one of the risk factors for non-contact ACL injury and has good predictive accuracy. The general population with FMBL angle below 33.7° may be increased risk for ACL injury.

HOW DO ANTERIOR CRUCIATE LIGAMENT INJURY AND RECONSTRUCTION AFFECT FUNCTIONAL KNEE EXTENSION? A SYSTEMATIC REVIEW AND META-ANALYSIS

Anterior cruciate ligament (ACL) ruptures are debilitating injuries, often managed via ACL reconstruction (ACLR). Reduced range of motion (ROM), particularly loss of extension (LOE), is the most significant contributor to post-operative patient dissatisfaction. LOE may preclude return to sport, increase re-rupture rates and precipitate osteoarthritis.Passive LOE rates following ACLR have been reported at 15%. However, LOE incidence during active tasks are poorly characterised. Our review sought to determine knee extension angles for active tasks following an ACL injury or ACLR. We hypothesised greater incidences of active LOE following ACL injury or ACLR, compared to uninjured contralateral limbs or controls.We systematically searched MEDLINE, Embase, Cochrane Library, Scopus, SPORTDiscus, and relevant trials databases for English articles. Included were cohort, cross-sectional, case-controlled or randomised controlled trials analysing adults with ACL injury treated surgically or otherwise, with at least 12-weeks follow-up and reporting either active knee extension angle, active LOE angles or incidence of active knee LOE during functional tasks. The protocol was registered on PROSPERO (CRD42018092295). Subsequent meta-analysis was performed.After screening, 71 eligible articles were included. Studies were heterogenous in design and quality. Included tasks were overground walking (n=44), running (n=3), hopping/jumping/cutting (n=11) single-leg landing (n=7), and stair climbing (n=6). LOE incidence varied depending on functional activities (33.95-92.74%). LOE incidence did not vary depending on ACL status (67.26% vs. 65.90% vs. 62.57% for ACL intact, ACLD and ACLR, respectively).We observed no difference in active LOE incidence according to ACL status. Importantly, the observed incidence for active LOE was reliably higher than previously reported rates for passive measures.Given the discrepancy between active and passive LOE incidence, clinicians may advisably prioritise active ROM during ACL rehabilitation.

Morphologic Risk Factor for ACL Rupture in Children Younger than Age 12: An Mri-Based Comparison

Background:There are findings in the adult and adolescent literature regarding anatomic variation that may lead to traumatic disruption of the anterior cruciate ligament (ACL). Previous studies have found an interaction between age and various morphologic risk factors but have been underpowered in assessing younger pediatric patients.Hypothesis/Purpose:The purpose of this study was to evaluate morphologic features of the knee in younger children to determine if any of these factors may contribute to risk of ACL injury in this age group.Methods:A retrospective review of knee MRIs was performed on pediatric patients evaluated at our facility for confirmed ACL rupture. Seven measures were performed and three ratios were calculated, which were compared to an age-matched control cohort previously used to establish and publish normative data of childhood knee MRIs. They were then grouped for statistical purposes by age: “child” aged 5 – 11 years, and “adolescents” aged 12 – 19 years. A generalized linear model was used to assess interaction between age and ACL status.Results:A total of 49 children age <12 years with ACL rupture were identified during the data collection period that met criteria for review. While intercondylar width and notch height index (NHI) were significant in the ACL-torn cohort at large (p=0.015 and p=0.001 respectively), this difference was not present in children. Conversely, tibial plateau to anterior tibial spine (ATS) height was different in ACL-torn children but not in adolescents (p=0.003). Notch Width Index (NWI) was significantly smaller in ACL torn children and adolescents (p<0.0001). When comparing age groups, NWI was the only variable that had minimal to no difference in the normal group, but a significant difference between children and adolescents in the ACL-torn group. No difference was found in Critical Notch Stenosis.Conclusion:Children and adolescents demonstrate the effect of multiple morphologic parameters on ACL tear risk. While there is overlap, there are risk factors specific to each age group. Uniquely, increased TP to ATS height was a risk factor for ACL tear in children. Despite the effect of age and ACL tear on NWI, there was no difference for Critical Notch Stenosis, suggesting that the current definition of critical notch stenosis should be adjusted. Given the difference between NWI in children and adolescents with ACL tear, it may be more appropriate to have age-based cutoffs for critical notch stenosis.

Posterior Tibial Slope in Patients With Torn ACL Reconstruction Grafts Compared With Primary Tear or Native ACL: A Systematic Review and Meta-analysis

Background:Increased posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) rupture and failure of ACL reconstruction (ACLR) grafts.Purpose:The purpose was to conduct a systematic review of literature on PTS measurements and to conduct a meta-analysis of comparable PTS measurements based on a patient’s ACL status. It was hypothesized that patients with torn ACLR grafts would have significantly larger medial and lateral PTS compared with patients with native ACLs or those who underwent primary ACLR.Study Design:Systematic review; Level of evidence, 4.Methods:A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were studies that reported medial and/or lateral PTS measurements, those that reported PTS measurements based on ACL status (ie, intact ACL, primary ACL tear, failed ipsilateral ACLR, or revision ACLR), and those that reported their specific PTS measurement technique. Average PTS measurements, measurement location (medial or lateral tibial plateau) and technique, imaging modality used, and ACL status were extracted from each study. Data were pooled using DerSimonian and Laird random-effects models, and results were compared using the Altman interaction test.Results:The literature search identified 1705 studies, of which 82 (N = 12,971 patients) were included. There were 4028 patients in the intact ACL group (31%), 7405 in the primary ACLR group (57%), and 1538 in the failed ACLR group (12%). Measurements were obtained from lateral radiographs in 31 studies (38%), from magnetic resonance imaging in 47 studies (57%), and from computed tomography in 4 studies (5%). The failed ACLR group had a significantly larger lateral PTS (9.55°; 95% CI, 8.47°-10.63°) than either the primary ACL tear (7.13°; 95% CI, 6.58°-7.67°) or intact ACL (5.57°; 95% CI, 5.03°-6.11°) groups (P < .001 for both). The failed ACLR group also had a significantly larger medial PTS (9.05°; 95% CI, 7.80°-10.30°) than the primary (6.24°; 95% CI, 5.71°-6.78°) or intact ACL (6.28°; 95% CI, 5.21°-7.35°) groups (P < .001 for both).Conclusion:Both lateral and medial PTS measurements were greater in patients who had failed previous ACLR than those with a primary ACL tear or an intact native ACL. The lateral PTS of patients with primary ACL tears was greater than those with an intact native ACL.

Value of passive anterior tibial subluxation on axial MRI in identifying anterior cruciate ligament functional deficiency in patients with advanced anteromedial osteoarthritis of the knee: a case-control study

BackgroundA functionally deficient anterior cruciate ligament (ACL) is considered one of the contraindications in unicompartmental knee arthroplasty (UKA). But there is still a lack of standardized and reproducible methods to assess ACL functional integrity in patients with advanced anteromedial osteoarthritis of the knee (AMOA). This study explores the value of passive anterior tibial subluxation (PATS) on axial MRI in evaluating ACL status in this population.MethodsPatients who met UKA indications between November 2017 and September 2020 were included and grouped into “intact” (ACLI) or “deficient” (ACLD) group according to their ACL status during surgery. All participants underwent MRI with a standardized protocol. The measurements of medial and lateral PATS were conducted on axial MRI, and the mean of them was calculated as global PATS. Then the reliability and diagnostic ability of PATS were determined.ResultsA total of 85 patients (45 for ACLI group, 40 for ACLD group) were included after selection. The measurements of PATS showed excellent intra- and inter-observer reliabilities (with an intraclass correlation coefficient of at least 0.986). The global PATS of the ACLI group was significantly lower than that of the ACLD group (− 2.30 ± 1.96 vs. 1.03 ± 1.96 mm, P<0.0001). The diagnostic ability of global PATS was good (area under the curve = 0.897), and a threshold of 1.2 mm had a specificity of 100%, a sensitivity of 55%, and an accuracy of 78.82%.ConclusionAn axial global PATS of 1.2 mm on MRI is greatly specific for identifying a functionally deficient ACL in patients with advanced AMOA.

Predictive Accuracy of Blumensaat Line Angle and Its Apex along with Anterior Cruciate Ligament Inclination Angle for Diagnosis of Anterior Cruciate Ligament Tear with Abundant Remnant.

Anterior Cruciate Ligament Blumensaat line angle and Anterior Cruciate Ligament Inclination angle can be measured when Anterior Cruciate Ligament is visualized on Magnetic Resonance Imaging. Both these angles can be helpful to determine the intactness of Anterior Cruciate Ligament. The aim of this study was to evaluate the diagnostic accuracy of Anterior Cruciate Ligament - Blumensaat line angle, apex of Anterior Cruciate Ligament - Blumensaat line angle and Anterior Cruciate Ligament - Inclination angle to determine the status of Anterior Cruciate Ligament in terms of tear or no tear. We conducted a prospective observational study with Magnetic Resonance Imagings of knees of 71 patients, who were divided into Anterior Cruciate Ligament tear and Anterior Cruciate Ligament intact groups based on Anterior Cruciate Ligament - Blumensaat line angle (<150- intact; ? 150 - torn Anterior Cruciate Ligament), Anterior Cruciate Ligament - Inclination angle (>450 - intact ACL; ? 450 - Anterior Cruciate Ligament tear) and apex of Anterior Cruciate Ligament - Blumensaat line angle ( apex towards femur - Intact Anterior Cruciate Ligament; apex towards tibia or parallel lines- Anterior Cruciate Ligament Tear) measured on MRI study. Diagnostic accuracy was calculated in terms of sensitivity, specificity, positive predictive value and negative predictive value of Anterior Cruciate Ligament - Blumensaat line angle, Anterior Cruciate Ligament - Inclination angle and apex of Anterior Cruciate Ligament - Blumensaat line angle. The sensitivity and specificity of Anterior Cruciate Ligament - Blumensaat line angle to detect Anterior Cruciate Ligament status was 95.83% and 95.35% respectively. Similarly, the sensitivity of Anterior Cruciate Ligament - Inclination angle was 95.83% and specificity was 95.35%. The sensitivity of Apex Anterior Cruciate Ligament - Blumensaat line angle to detect Anterior Cruciate Ligament tear on MRI was calculated to be 95.74% and a specificity of 87.5% Conclusions: Anterior Cruciate Ligament - Blumensaat line angle and Anterior Cruciate Ligament - Inclination angle is highly sensitive and specific for the diagnosis of Anterior Cruciate Ligament tear. Apex of Anterior Cruciate Ligament - Blumensaat line angle is also helpful in determination of Anterior Cruciate Ligament tear.

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BackgroundThe present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee. MethodsOne hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups. ResultsKnees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm. ConclusionFunctional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.

Impact of Anterior Cruciate Ligament Status on Early Satisfaction and Clinical Outcomes Following Total Knee Arthroplasty

Introduction&#x0D; While total knee arthroplasty (TKA) is a successful treatment for debilitating arthritis, up to 20% of patients may be dissatisfied with their outcome. One hypothesis for dissatisfaction is the distortion of native knee kinematics following sacrifice of the anterior cruciate ligament (ACL) during TKA. The purpose of this study was to determine the impact of ACL status at the time of surgery in patients undergoing Posterior Stabilized (PS) TKA for osteoarthritis (OA).&#x0D; Methods&#x0D; A consecutive prospective series of patients undergoing TKA by a single surgeon underwent prospective intraoperative assessment of their ACL status divided into three different groups:1) intact, 2) attenuated, or 3) deficient. Demographic, preoperative, intraoperative, and postoperative data were collected for each patient by two blinded, independent observers. Outcomes included patient satisfaction and Knee Society Score for Pain (KSS) and Function (KSF), Kellgren and Lawrence (K&amp;L), UCLA Activity Score (UCLA), Short Form-12 (SF12), EuroQol (EQ5D) and patient satisfaction.&#x0D; Results:&#x0D; Of 116 patients, 33 (28.4%) patients had an ACL deficient knee, 40 (34.5%) patients had an attenuated ACL, and 43 (37.1%) patients had an intact ACL. Those with absent ACL were significantly more likely to have a higher BMI (p=.007) and be male (p=.003). Patient with a deficient ACL had significantly lower preoperative KSF and higher K&amp;L scores (p=.009, p=1.26 x 10-7). Attenuated and deficient groups had the greatest change in SF12PCS scores at their one-year follow-up with increases of 9.9 (±10.0) and 10.8 (±8.0), respectively (p=.037). No significant differences in overall postoperative KSS, KSF and satisfaction scores based on ACL status (p=.574 and p=.529, respectively) were found.&#x0D; Conclusion&#x0D; In a relatively large series, patient with ACL deficiency were more likely to have worse pre-operative outcome scores and similar or better post-operative outcome scores. This suggests that those with ACL insufficiency may experience more subjective improvement from TKA. ACL status can be used as an additional surgical marker to help orthopaedic surgeons identify which patients would most benefit from TKA.

Patterns of cartilage loss and anterior cruciate ligament status in end-stage osteoarthritis of the knee.

This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status. A cross-sectional analysis of 300 consecutive patients (mean age 69 years (SD 9.5, 44 to 91), mean body mass index (BMI) 30.6 (SD 5.5, 20 to 53), 178 female (59.3%)) undergoing total knee arthroplasty (TKA) for Kellgren-Lawrence grade ≥ 3 knee OA was conducted. The point of maximal tibial bone loss on preoperative lateral radiographs was determined as a percentage of the tibial diameter. At surgery, Lachman's test and ACL status were recorded. The presence of full-thickness cartilage loss within 16 articular surface regions (two patella, eight femoral, six tibial) was recorded. According to articular cartilage loss and ACL status, 195/293 (67%) were suitable for PKA or CPKA: medial unicompartmental knee arthroplasty (UKA) 97/293 (33%); lateral UKA 25 (9%); medial bicompartmental arthroplasty 31 (11%); lateral bicompartmental arthroplasty 12 (4%); bicondylar-UKA 23 (8%); and patellofemoral arthroplasty (PFA) seven (2%). The ACL was intact in 166 (55%), frayed in 82 (27%), disrupted in 12 (4%), and absent in 33 (11%). Lachman testing was specific (97%) but poorly sensitive (38%) for disrupted/absent ACLs. The point of maximal tibial bone loss showed good interclass correlation (ICC 0.797, 0.73 to 0.85 95% confidence interval (CI); p < 0.001) and was more posterior when the ACL was absent. Maximum tibial bone loss occurring at > 55% of the anterior to posterior distance predicted ACL absence with 93% sensitivity and 91% specificity (area under the curve 0.97 (0.94 to 0.99 95% CI; p < 0.001). ACL status can be reliably determined from a lateral radiograph using the location of maximal tibial bone loss. According to regions of cartilage loss and ACL status, two-thirds of patients with end-stage knee OA could potentially be treated with PKA or CPKA. Cite this article: Bone Joint J 2020;102-B(6):716-726.

How does geometric change after open-wedge high tibial osteotomy affect anterior cruciate ligament status?

BackgroundOpen-wedge high tibial osteotomy (OWHTO) produces three- dimensional (3D) geometric changes. Among them, increased posterior tibial slope (PTS), and altered coronal inclination that induces unintended tibial translation may affect anterior cruciate ligament (ACL) status. The purpose of current study was to evaluate the geometric changes following OWHTO, such as increasing PTS and decreasing tibial subluxation, which may affect the status of ACL. MethodsFrom April 2014 to December 2015, a total of 72 knees in 64 patients that underwent OWHTO, second-look arthroscopy, and magnetic resonance imaging (MRI) assessment, were enrolled. Preoperative and postoperative coronal and sagittal translation, joint line orientation angle, the distance between medial femoral notch marginal line and medial tibial spine, and PTS were evaluated. ACL status was arthroscopically graded from grade 1 (best) to 4 (worst). The MRI signal of the graft in three portions (proximal, middle, and distal) was graded from grade 1 (best) to 4 (worst). ResultsHigh grade (3: partial, and 4: complete rupture) was noted in 28 cases (38.9%) at the second-look arthroscopy compared with 10 cases (13.9%) at index arthroscopy. The MRI signal grade significantly increased at follow up MRI compared with preoperative MRI (P<0.01). An increased signal was commonly noted in the middle and distal portions of the graft. ConclusionsGeometric changes after OWHTO were related to ACL deterioration. The ACL was commonly affected at the middle and distal portions and rarely at the proximal portion. There is a possibility of impingement because of the geometric changes.Level of evidence: Level IV

Towards improving the identification of anterior cruciate ligament tears in primary point-of-care settings

BackgroundOnly a small proportion of anterior cruciate ligament (ACL) tears are diagnosed on initial healthcare consultation. Current clinical guidelines do not acknowledge that primary point-of-care practitioners rely more heavily on a clinical history than special clinical tests for diagnosis of an ACL tear. This research will assess the accuracy of combinations of patient-reported variables alone, and in combination with clinician-generated variables to identify an ACL tear as a preliminary step to designing a primary point-of-care clinical decision support tool.MethodsElectronic medical records (EMRs) of individuals aged 15–45 years, with ICD-9 codes corresponding to a knee condition, and confirmed (ACL+) or denied (ACL−) first-time ACL tear seen at a University-based Clinic between 2014 and 2016 were eligible for inclusion. Demographics, relevant diagnostic indicators and ACL status based on orthopaedic surgeon assessment and/or MRI reports were manually extracted. Descriptive statistics calculated for all variables by ACL status. Univariate between group comparisons, clinician surveys (n = 17), availability of data and univariable logistic regression (95%CI) were used to select variables for inclusion into multivariable logistic regression models that assessed the odds (95%CI) of an ACL-tear based on patient-reported variables alone (consistent with primary point-of-care practice), or in combination with clinician-generated variables. Model performance was assessed by accuracy, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (95%CI).ResultsOf 1512 potentially relevant EMRs, 725 were included. Participant median age was 26 years (range 15–45), 48% were female and 60% had an ACL tear. A combination of patient-reported (age, sport-related injury, immediate swelling, family history of ACL tear) and clinician-generated (Lachman test result) variables were superior for ACL tear diagnosis [accuracy; 0.95 (90,98), sensitivity; 0.97 (0.88,0.98), specificity; 0.95 (0.82,0.99)] compared to the patient-reported variables alone [accuracy; 84% (77,89), sensitivity; 0.60 (0.44,0.74), specificity; 0.95 (0.89,0.98)].ConclusionsA high proportion of individuals without an ACL tear can be accurately identified by considering patient-reported age, injury setting, immediate swelling and family history of ACL tear. These findings directly inform the development of a clinical decision support tool to facilitate timely and accurate ACL tear diagnosis in primary care settings.

Correlations between radiological classification systems and confirmed cartilage loss in severe knee osteoarthritis.

Although knee osteoarthritis (OA) is diagnosed and monitored radiologically, actual full-thickness cartilage loss (FTCL) has rarely been correlated with radiological classification. This study aims to analyze which classification system correlates best with FTCL and to assess their reliability. A prospective study of 300 consecutive patients undergoing unilateral total knee arthroplasty (TKA) for OA (mean age 69 years (44 to 91; standard deviation (SD) 9.5), 178 (59%) female). Two blinded examiners independently graded preoperative radiographs using five common systems: Kellgren-Lawrence (KL); International Knee Documentation Committee (IKDC); Fairbank; Brandt; and Ahlbäck. Interobserver agreement was assessed using the intraclass correlation coefficient (ICC). Intraoperatively, anterior cruciate ligament (ACL) status and the presence of FTCL in 16 regions of interest were recorded. Radiological classification and FTCL were correlated using the Spearman correlation coefficient. Knees had a mean of 6.8 regions of FTCL (SD 3.1), most common medially. The commonest patterns of FTCL were medial ± patellofemoral (143/300, 48%) and tricompartmental (89/300, 30%). ACL status was associated with pattern of FTCL (p = 0.023). All radiological classification systems demonstrated moderate ICC, but this was highest for the IKDC: whole knee 0.68 (95% confidence interval (CI) 0.60 to 0.74); medial compartment 0.84 (95% CI 0.80 to 0.87); and lateral compartment 0.79 (95% CI 0.73 to 0.83). Correlation with actual FTCL was strongest for Ahlbäck (Spearman rho 0.27 to 0.39) and KL (0.30 to 0.33) systems, although all systems demonstrated medium correlation. The Ahlbäck score was the most discriminating in severe knee OA. Osteophyte presence in the medial compartment had high positive predictive value (PPV) for FTCL, but not in the lateral compartment. The Ahlbäck and KL systems had the highest correlation with confirmed cartilage loss at TKA. However, the IKDC system displayed the best interobserver reliability, with favourable correlation with FTCL in medial and lateral compartments, although it was less discriminating in more severe disease. Cite this article: Bone Joint J 2020;102-B(3):301-309.

Subjective Knee Function and Risk of Failure Are Equivalent for Men and Women at 5 Years After Meniscus Repair

To determine whether subjective knee function or risk of repair failure differ between men and women at mean 5 years following meniscal repair with or without concomitant anterior cruciate ligament reconstruction. A total of 235 patients (97 women, 138 men; mean age, 29.1 years; standard deviation, 11.3) were assessed for meniscus repair failure and postoperative knee function at mean 5.8 years follow-up. Knee symptoms were assessed with International Knee Documentation Committee Subjective (IKDC-S) scores. Postoperative activity scores were assessed with Marx activity score. Independent effects of patient age and activity level on meniscus failure risk and patient-reported outcomes were determined by multivariate analysis with adjustment for age, body mass index, anterior cruciate ligament status, tear pattern, and number of implants used at the time of surgery. Failures occurred in 18.9% of men and 21.0% of women with no difference in mean time to failure (P= .75) or risk of failure for men vs women (P= .57) in the univariate analysis. Male sex was not an independent risk factor for failure after adjustment for patient age, body mass index, concomitant anterior cruciate ligament status, tear pattern, or number of implants used (P= .16). Marx activity scores at follow-up were higher among men in multivariate analysis (P= .009). Men and women had similar IKDC-S scores at follow-up in the unadjusted (P= .25) and multivariate analyses (P= .21). Following meniscus repair, both sexes report similar subjective knee function, though men have higher self-reported activity scores. Meniscus repair failure risk does not differ between men or women at mid-term follow up. Level III, retrospective case-control study.

Relationship between Femoral Intercondylar Notch Narrowing in Radiography and Anatomical and Histopathologic Integrity of Anterior Cruciate Ligament in Patients Undergoing Total Knee Replacement Surgery.

The presence of cruciate ligaments is very important for normal knee kinematics. Knee arthroplasty prostheses, in which these ligaments are maintained, have better kinematics. The aim of the present study was to investigate the association between femoral intercondylar notch (FIN) narrowing in radiography and clinical and histopathologic integrity of anterior cruciate ligament (ACL) in patients undergoing knee replacement surgery. FIN index was measured in tunnel view radiography of the knees of 102 candidates of knee replacement surgery. The anatomical status of ACL was also examined during total knee arthroplasty (TKA). ACL was removed and sent for histopathologic examination to assess its degeneration rate. The association between the FIN index and the clinical and histopathological health of ACL was investigated. Among 102 patients with mean age of 69.73 ± 7.81 years , 39 patients (38.32%) had no or torn ACL, 31 patients (30.39%) had weak ACL, and 32 (31.37%) had normal ACL. There was a significant association between age and clinical status of ACL during surgery (P=0.017). There was a significant difference in FIN and ACL health status during surgery between the two groups with an index of more and less than 0.252 (P=0.019 and P=0.019, respectively). There was no significant difference in the mean total degeneration score (TDS) of ACL between the two groups with FIN more and less than 0.252 (P=0.816). There was a significant difference between the age and FIN narrowing (less than 0.252) as well as ACL clinical status during surgery. FIN narrowing had no significant effect on the severity of ACL degeneration and there was no significant difference in the severity of degenerative histopathologic changes between healthy and attenuated ACLs. This indicates that if ACL exists, although apparently attenuated, it has the histologic characteristic of a healthy ligament.

The Femoral Footprint Position of the Anterior Cruciate Ligament Might Be a Predisposing Factor to a Noncontact Anterior Cruciate Ligament Rupture

Background: Although the femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, the recommendations for the ideal femoral footprint position are mostly based on cadaveric studies with small sample sizes, elderly patients with unknown ACL status, and 2-dimensional techniques. Furthermore, a potential difference in the femoral ACL footprint position and ACL orientation between ACL-ruptured and ACL-intact knees has not been reported in the literature. Hypothesis: The femoral ACL footprint position and ACL orientation vary significantly between ACL-ruptured and matched control ACL-intact knees. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Magnetic resonance images of the knees of 90 patients with an ACL rupture and 90 matched control participants who had a noncontact knee injury without an ACL rupture were used to create 3-dimensional models of the femur and tibia. The ACL footprints were outlined on each model, and their positions (normalized to the lateral condyle width) as well as ACL orientations were measured with an anatomic coordinate system. Results: The femoral ACL footprint in patients with an ACL rupture was located at 36.6% posterior and 11.2% distal to the flexion-extension axis (FEA). The ACL orientation was 46.9° in the sagittal plane, 70.3° in the coronal plane, and 20.8° in the transverse plane. The ACL-ruptured group demonstrated a femoral ACL footprint position that was 11.0% more posterior and 7.7% more proximal than that of the control group (all P < .01). The same patients also exhibited 5.7° lower sagittal elevation, 3.1° higher coronal plane elevation, and 7.9° lower transverse plane deviation (all P < .01). The optimal cutoff value of the femoral ACL footprint position to prevent an ACL rupture was at 30% posterior and 12% distal to the FEA. Conclusion: The ACL femoral footprint position might be a predisposing factor to an ACL rupture. Patients with a >30% posterior and <12% distal position of the femoral ACL footprint from the FEA might have a 51.2-times increased risk of an ACL rupture.

The effect of alignment on knee osteoarthritis initiation and progression differs based on anterior cruciate ligament status: data from the Osteoarthritis Initiative.

Knee alignment and anterior cruciate ligament (ACL) injury are risk factors for knee osteoarthritis (OA). The objective was to examine interactions between knee alignment and ACL status on cartilage volume loss in participants with or at risk of knee OA. Participants were from the Osteoarthritis Initiative, a longitudinal cohort study. Data were from baseline and 24- and 72-month follow-up visits. Participants with knee OA (progression subcohort) or at risk of knee OA (incidence subcohort) that had partial or full ACL tears (OA-ACL group; n=66) or an intact ACL (OA-only group, n=367) were selected. Femur-tibia angles from radiographs quantified knee alignment. Changes in tibial and femoral cartilage volumes were measured using magnetic resonance imaging. Hierarchical linear models examined if knee alignment, presence of ACL, and their interaction were related to cartilage volume loss after accounting for other variables. Interactions between alignment and ACL status were significantly related to cartilage volume loss in the lateral plateau (β=-20.19, 95% confidence interval [CI]=-34.65 to -5.73) and lateral condyle (β=-23.64, 95%CI=-43.06 to -4.23). Valgus alignment was related to lateral compartment cartilage loss in the OA-ACL group, but not in the OA-only group. Varus alignment was related to cartilage loss in the medial plateau (β=7.49, 95%CI=0.17 to 14.80) and medial condyle (β=19.70, 95%CI=5.96 to 33.44) in both groups. The impact of knee alignment on knee OA initiation and progression varies based on ACL status. Initial lateral compartment damage or changes in joint kinematics after ACL rupture might account for these findings.Key Points• The relationship between knee alignment and lateral compartment cartilage loss depended on the status of the anterior cruciate ligament in participants with knee osteoarthritis or at risk for knee osteoarthritis.• Valgus alignment was related to lateral compartment cartilage loss in participants with a deficient anterior cruciate ligament.• Varus alignment was related to medial compartment cartilage loss regardless of the status of the anterior cruciate ligament.