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Background: Anterior cruciate ligament (ACL) tears are commonly seen with concomitant injuries to the posterolateral tibial plateau, while the occurrence of ACL injuries in posterolateral tibial plateau fractures (PTPFs) remains unclear. Purpose: To (1) explore the incidence of knee ligament (anterior or posterior cruciate ligament, medial or lateral collateral ligament) and medial or lateral meniscus injuries in patients with PTPF and (2) find reliable PTPF-related parameters to predict the risk of knee ligament and meniscal injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients diagnosed with PTPF who had computed tomography and magnetic resonance imaging (MRI) data were identified. Morphological parameters of the PTPF were measured on sagittal computed tomography images. Knee ligament and meniscal injuries were assessed using MRI. The association of ACL injuries with meniscal injuries was analyzed. Receiver operating characteristic (ROC) analysis was used to determine the value and cutoff point of the PTPF morphological parameters for diagnosing complete in-substance ACL tears. Results: Overall, 113 patients with PTPF were included. ACL injuries were present in 94 (83.2%) patients, including 43 (38.1%) avulsion fractures and 28 (24.8%) complete in-substance tears. Patients with in-substance ACL tears had a higher incidence of lateral meniscus posterior horn tears compared with the other patients (PBonferroni < .001). ROC analysis revealed that both the fracture depression angle (cutoff point, 25.5°) and the posterior articular surface loss percentage (cutoff point, 37.5%) had a sensitivity >90% and a specificity >80% for the diagnosis of complete in-substance ACL tears. Conclusion: ACL injuries were seen in 83.2% of the study patients. Complete in-substance ACL tears were associated with an increased incidence of lateral meniscus posterior horn tears. Among PTPF parameters, fracture depression angle and posterior articular surface loss percentage showed a high predictive value for the presence of complete in-substance ACL tears, thereby reducing delays in diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) tears are prevalent orthopedic sports injuries and are difficult to precisely classify. Previous works have demonstrated the ability of deep learning (DL) to provide support for clinicians in ACL tear classification scenarios, but it requires a large quantity of labeled samples and incurs a high computational expense. This study aims to overcome the challenges brought by small and imbalanced data and achieve fast and accurate ACL tear classification based on magnetic resonance imaging (MRI) of the knee. We propose a lightweight attentive graph neural network (GNN) with a conditional random field (CRF), named the ACGNN, to classify ACL ruptures in knee MR images. A metric-based meta-learning strategy is introduced to conduct independent testing through multiple node classification tasks. We design a lightweight feature embedding network using a feature-based knowledge distillation method to extract features from the given images. Then, GNN layers are used to find the dependencies between samples and complete the classification process. The CRF is incorporated into each GNN layer to refine the affinities. To mitigate oversmoothing and overfitting issues, we apply self-boosting attention, node attention, and memory attention for graph initialization, node updating, and correlation across graph layers, respectively. Experiments demonstrated that our model provided excellent performance on both oblique coronal data and sagittal data with accuracies of 92.94% and 91.92%, respectively. Notably, our proposed method exhibited comparable performance to that of orthopedic surgeons during an internal clinical validation. This work shows the potential of our method to advance ACL diagnosis and facilitates the development of computer-aided diagnosis methods for use in clinical practice. [ABSTRACT FROM AUTHOR]

Objective: To 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. Methods: In 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. Results: Out 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. Conclusion: The 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. [ABSTRACT FROM AUTHOR]

Aberrant mechanical forces were considered as an important factor for osteoarthritis (OA) pathogenesis. Plant homeodomain finger-containing protein 8 (PHF8) participated in osteogenic differentiation and inflammatory progression. However, the role of PHF8 in aberrant force-related OA remains to be elucidated. In this study, a fluid shear stress (FSS) model in ATDC5 cells and an anterior cruciate ligament transection (ACLT) animal model were constructed. The results revealed the decrease of PHF8 in aberrant force-induced cartilage damage in vitro and in vivo. PHF8 overexpression alleviated the aberrant force-induced cell apoptosis, extracellular matrix degradation, and inflammation. Chromatin immunoprecipitation (ChIP) assays demonstrated that PHF8 epigenetically regulated WWP2 expression through demethylating H3K9me2 at WWP2 promoter, which was influenced by FSS treatment. C-X-C chemokine receptor type 4 (CXCR4) was identified as a potential substrate of WWP2. Co-immunoprecipitation (Co-IP) and ubiquitination experiments further demonstrated WWP2 decreased the stability of CXCR4 via the ubiquitination pathway. Subsequently, rescue experiments validated reintroduction of WWP2 significantly attenuated the effects of PHF8 deletion on FSS-induced chondrocyte injury, and CXCR4 overexpression reversed the protective effects of WWP2 overexpression on chondrocyte injury in FSS-treated ATDC5 cells. Moreover, delivery of a PHF8 adeno-associated virus (AAV) into articular cartilage remarkably ameliorated the breakdown of cartilage matrix by ACLT in mice. In conclusion, our findings highlighted the importance of PHF8/WWP2/CXCR4 signaling pathway in aberrant force-induced cartilage injury, which might provide a novel insight on future epigenetic-based treatment of posttraumatic OA. [ABSTRACT FROM AUTHOR]

Background: Measurement of knee laxity after anterior cruciate ligament (ACL) injury is crucial for appropriate treatment and rehabilitation decision-making. This study examined the potential of a new digital arthrometer (Ligs, Innomotion, Shanghai, China) to quantify anterior tibial translation (ATT) in patients with ACL injuries and in healthy subjects. Methods: A total of 60 participants included 30 subjects with single-leg ACL injuries and 30 healthy subjects included as controls. The lower leg was immobilized. The thruster is positioned posterior to the lower leg and parallel to the tibial tuberosity in the sagittal plane. The load is applied vertically to the tibia under a dynamic load of 0–150 N, with continuous displacement recorded. The intrarater and interrater reliability will be examined. ATT and side-to-side differences (SSD) between the control and ACL injury groups were compared. Receiver operating characteristic (ROC) curves were analyzed, and the area under the curve (AUC) was calculated to determine the diagnostic accuracy of the Ligs. Results: The interrater ICC was 0.909 and the intrarater ICC was 0.943. Significant differences in the SSD were observed between the control and ACL injury groups (for all P < 0.05), with the largest effect size (ES = 1.12) at 80 N. When comparing ATT at different loads between injured and healthy sides in the ACL injury group, displacement was statistically significant at different loads. At a load of 150 N, the AUC was the maximum (0.857) and the sensitivity and specificity were 0.87 and 0.73, respectively. Conclusions: A digital arthrometer can be used as a quantitative instrument to quantify knee laxity. Quantitative measurement of ATT and SSD under controlled loading can be an objective and effective tool for clinical practice. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injury can lead to changes in tibiofemoral kinematics during gait, but the detailed short-term kinematic changes after ACL injury are still unknown. Purpose: To measure tibiofemoral kinematics during gait in ACL-deficient (ACLD) knees over time after ACL injury. Study Design: Controlled laboratory study. Methods: The authors categorized 76 patients with unilateral ACLD knees into 4 groups based on the time from injury: <3 months (group 1), 3 to 6 months (group 2), >6 to 12 months (group 3), and >12 months (group 4). The controls were 20 participants with ACL-intact knees. Changes in the knee kinematics and range of motion during gait were compared among ACLD groups and those with ACL-intact knees. Results: Compared with controls, the range of motion of flexion in group 1 was significantly lower (6°; P =.033), and the mean knee flexion was significantly increased (0.7°-3.4°) in groups 1 to 4 (all P ≤.004). There was more internal tibial rotation (2.9°-4.3°) in group 1 and 2, and more anterior tibial translation (4.3 mm) in group 1 during the stance or swing phases than in controls (P ≤.049 for all). The mean internal tibial rotation and anterior tibial translation significantly decreased from group 1 to group 4 (P <.001 for both). Compared with controls, the mean medial tibial translation was significantly greater (1.2-2.5 mm) in all groups, and more medial tibial translations (2.4-3.7 mm) were observed during the stance phase in groups 1, 3, and 4 (P ≤.047 for all). Conclusion: ACLD knees displayed a motion impairment walking strategy within 3 months, and a higher-flexion walking strategy increased with time after injury. Excessive anterior translation and internal rotation of the tibia tended to return to normal, while excessive medial translation of the tibia increased in ACLD knees after 6 months postinjury. These results may provide new insight into the compensatory mechanisms and risk factors for premature osteoarthritis in ACLD knees. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anterior cruciate ligament injury is one of the most common injuries of the knee joint. Bibliometrics and visual analysis of related research on anterior cruciate ligament reconstruction can help clarify the research process in this field and quickly understand the current research hotspots. A reasonable estimate of future research trends can promote the further development of this field. OBJECTIVE: To analyze the global research status, hot spots and future development trends of anterior cruciate ligament reconstruction. METHODS: Web of Science Core Collection was retrieved for publications related to anterior cruciate ligament reconstruction published from 1995 to 2019. Citespace software was used to analyze the cluster, co-occurrence and burst words of the included literatures. RESULTS AND CONCLUSION: A total of 9 020 articles in English were included, involving 20 566 authors, 55 countries and regions, 6 117 research institutes, and 690 publication sources. The global publication volume showed a trend of fluctuating increase year by year, and reached a peak of 866 articles in 2019. The United States has an absolute advantage in the research of anterior cruciate ligament reconstruction, ranking first in terms of publication volume and H index. China ranks 4th in total publications and 11th in the H index. Top five clusters of key words in anterior cruciate ligament reconstruction research included rehabilitation, autograft, prevalence, return to sport, and injury. Burst words highlighted from 2014 to 2019 included: outcome, sports, return, risk, anterolateral ligament, and revision. The co-citation analysis of references showed that the top five literatures with highest citation frequency were all published between 2010 and 2014, three of which are related to sport recovery. The top five clusters included long term, single bundle, interference screw, risk factor and return. In conclusion, the selection of grafts and internal fixators and postoperative rehabilitation are the main research hotspots at present. The topics such as return to sport as soon as possible through rehabilitation treatment, prevention of postoperative ligament secondary injury, reasonable treatment of postoperative complications, and ligament revision will become new research hotspots in the future related to anterior cruciate ligament reconstruction. The quality of China’s publications and international cooperation in this field need to be strengthened. [ABSTRACT FROM AUTHOR]

Background: Controversy remains regarding the optimal technique for tibial fixation of soft tissue grafts in anterior cruciate ligament (ACL) reconstruction. Purpose/Hypothesis: To compare the biomechanical outcomes of a novel transtibial tubercle fixation technique with those of a commonly utilized interference screw fixation at the tibial site. Our hypothesis was that transtibial tubercle fixation achieves higher ultimate failure loads than interference screw fixation. Study Design: Controlled laboratory study. Methods: We used 24 matched porcine tibias and digital extensor tendons, from which 12 grafts and tibial tunnels were prepared using the novel transtibial tubercle fixation technique and 12 were prepared using the interference screw fixation technique. The specimens underwent a cyclic loading test (50-250 N applied for 1000 cycles at a frequency of 1 Hz), followed by a load-to-failure test. The slippage, stiffness, and ultimate failure loads were compared between the techniques. Results: No differences in slippage were found during the cyclic loading test, and no graft fixation or tibial complex failures occurred during cyclic testing in either group. The transtibial tubercle fixation technique had higher ultimate failure loads (mean ± SD, 756.28 ± 123.43 N) as compared with interference screw fixation (602.15 ± 81.62 N; P <.05). The grafts in the transtibial tubercle fixation group were less stiff than those in the interference screw fixation group (84.43 vs 101.23 N/mm; P <.05). Conclusion: Transtibial tubercle fixation achieved higher ultimate failure loads than interference screw fixation in the load-to-failure test. Clinical Relevance: The novel transtibial tubercle fixation technique compared favorably with interference screw fixation during ACL reconstruction. This technique does not require hardware, has a low cost, theoretically eliminates the risk of complications associated with hardware implantation (eg, graft damage and pain attributed to retained hardware requiring removal), and is relatively easy to perform. [ABSTRACT FROM AUTHOR]

The stop-jumping task is one of the most important technical actions in basketball. A previous study showed 70% probability of non-contact ACL injuries during stop-jumping tasks. Therefore, the present study aimed to investigate the differences in lower extremity biomechanical changes between the rear foot as the initial contact area to terminate the jump (SJR) and the fore foot as the initial contact area to also terminate the jump (SJF) during the horizontal landing during a stop-jumping phase. In total, 25 male amateur Ningbo University basketball athletes from China were recruited for this study. The participants were asked to jump vertically by using two different stop-jumping strategies. Kinematic and kinetics data were amassed during a stop-jumping task. Statistical parametric mapping (SPM) analysis was used to find the differences between SJR and SJF. Our results indicated that the change of different ankle range of motion caused significantly different values for knee angle (p < 0.001), velocity (p = 0.003) (p = 0.023) (p < 0.001), moment (p = 0.04) (p < 0.001), (p = 0.036) and power (p = 0.015) (p < 0.001) during the stop-jumping phase and the horizontal landing phase. The same biomechanical parameters of the hip joint were also significantly different for hip angle (p < 0.001), moment (p = 0.012) (p < 0.001) (p < 0.001), and power (p = 0.01) (p < 0.001) (p < 0.001). These findings indicate that altering the primary contact at the ankle angle might effectively reduce the risk of a knee injury. [ABSTRACT FROM AUTHOR]

We conducted an epidemiological study to identify the demographics and pre-operative characteristics of patients undergoing primary anterior cruciate ligament (ACL) reconstruction in a multi-ethnic Asian population. A retrospective study was performed on 696 patients who registered in our ACL reconstruction registry from January 2013 to August 2016. Important inter-ethnic differences were found. Indian patients were significantly older compared to Malay and Chinese patients. Malay and Indian patients were more likely to be male, overweight, and obese compared to Chinese patients. Soccer was the predominant sport involved, although ethnic predominance in specific sports exists. Novel findings from this study include increased prevalence of concomitant chondral injuries in the Chinese population compared to Malays and Indians, and significantly higher rates of concomitant intra-articular injuries in soccer and basketball compared to netball. Identification of these high-risk subgroups would serve useful in guiding the formulation of prevention strategies within our multi-ethnic community. [ABSTRACT FROM AUTHOR]

A variety of factors have been linked to the occurrence of anterior cruciate ligament injury (ACLI), including sex, familial factors, and genetic variations. To find the genetic loci associated with ACLI and explore the genetic mechanism of ACLI in order to provide a genetic basis for the diagnosis, prognosis, and treatment of patients with ACLI. Cross-sectional study. Hospital. Data from 101 Chinese Yunnan Han patients with ACLI and 110 Yunnan Han individuals without ACLI (control group) were collected. The single nucleotide polymorphisms of COL1A1 rs1800012, COL5A1 rs12722 and rs13946, COL12A1 rs970547 and rs240736 and the rs1800787, rs1800788, rs1800789, rs1800790, rs1800791, and rs2227389 in the β-fibrinogen (β-fib) promoter region were analyzed using restriction fragment length polymorphism and DNA sequencing detection, and their genetic associations with ACLI were assessed. Single nucleotide polymorphisms of COL1A1 rs1800012, COL5A1 rs12722 and rs13946, and the rs1800789 and rs1800791 in the β-fib promoter region showed no difference between patients with ACLI and control participants, but the changes of COL12A1 rs970547 and rs240736 and the rs1800787, rs1800788, rs1800790, and rs2227389 genotypes in the β-fib promoter region were associated with ACLI. Furthermore, the rs970547 allele and genotype frequencies in male ACLI patients were different from the control group (P <.05): the frequencies of the rs970547 A and G alleles in the patients were 71.9% and 28.1%, respectively, and in the control group were 58.8% and 41.2%, respectively. The frequencies of AA, AG, and GG genotypes in the patients were 49.3%, 45.2%, and 5.5%, respectively, and in the control group were 27.5%, 62.7%, and 9.8%, respectively, suggesting that male carriers of rs970547 A and rs970547 AA were at high risk of ACLI. Males with the rs970547 A allele and rs970547 AA genotype of COL12A1 may be at high risk for ACLI. Low rs1800787 TT and high rs1800788 CT, rs1800790 AG, and rs2227389 CT frequencies as well as high TGA* of rs1800790, rs1800791, and rs2227389 in the β-fib promoter region may be genetic risk factors related to ACLI. [ABSTRACT FROM AUTHOR]

A variety of factors have been linked to the occurrence of anterior cruciate ligament injury (ACLI), including sex, familial factors, and genetic variations. To find the genetic loci associated with ACLI and explore the genetic mechanism of ACLI in order to provide a genetic basis for the diagnosis, prognosis, and treatment of patients with ACLI. Cross-sectional study. Hospital. Data from 101 Chinese Yunnan Han patients with ACLI and 110 Yunnan Han individuals without ACLI (control group) were collected. The single nucleotide polymorphisms of COL1A1 rs1800012, COL5A1 rs12722 and rs13946, COL12A1 rs970547 and rs240736 and the rs1800787, rs1800788, rs1800789, rs1800790, rs1800791, and rs2227389 in the β-fibrinogen (β-fib) promoter region were analyzed using restriction fragment length polymorphism and DNA sequencing detection, and their genetic associations with ACLI were assessed. Single nucleotide polymorphisms of COL1A1 rs1800012, COL5A1 rs12722 and rs13946, and the rs1800789 and rs1800791 in the β-fib promoter region showed no difference between patients with ACLI and control participants, but the changes of COL12A1 rs970547 and rs240736 and the rs1800787, rs1800788, rs1800790, and rs2227389 genotypes in the β-fib promoter region were associated with ACLI. Furthermore, the rs970547 allele and genotype frequencies in male ACLI patients were different from the control group (P <.05): the frequencies of the rs970547 A and G alleles in the patients were 71.9% and 28.1%, respectively, and in the control group were 58.8% and 41.2%, respectively. The frequencies of AA, AG, and GG genotypes in the patients were 49.3%, 45.2%, and 5.5%, respectively, and in the control group were 27.5%, 62.7%, and 9.8%, respectively, suggesting that male carriers of rs970547 A and rs970547 AA were at high risk of ACLI. Males with the rs970547 A allele and rs970547 AA genotype of COL12A1 may be at high risk for ACLI. Low rs1800787 TT and high rs1800788 CT, rs1800790 AG, and rs2227389 CT frequencies as well as high TGA* of rs1800790, rs1800791, and rs2227389 in the β-fib promoter region may be genetic risk factors related to ACLI. [ABSTRACT FROM AUTHOR]

BACKGROUND: Side-step cutting is the most common offensive technique in the field of sports that greatly increases the risk of knee injury. However, the biomechanical performance strategies and the characteristics of lower limb joint load during the side-step cutting are not very clear. OBJECTIVE: To carry out the biomechanics test of the side-step cutting in lower limb movement strategy among college female basketball and football players, and to analyze the kinematics and dynamics parameters of the lower limbs, providing an important reference for athletes and trainers to prevent lower limb injuries, especially cruciate ligament injury. METHODS: Twelve female football and basketball players coming from a university were selected as the experimental subjects. The kinematics and dynamics parameters of the side-step cutting were acquired synchronously by using the three-dimensional dynamometer and the motion image shooting system. The relevant data were processed and analyzed by SPSS 21.0 software. The study protocol was approved by Tianjin University of Sports in China. RESULTS AND CONCLUSION: (1) Football players had greater ankle metatarsal flexion angle and hip abduction angle, maximum ankle valgus angle, knee flexion and rotation angle with knee flexion and rotation angle changes. {2) Football players had greater peak ankle rotation and hip adduction moment, while basketball players had larger plantar flexion moment. (3} Basketball players have smaller first and second peak values of forward and backward partial braking force, the first peak value of vertical partial braking force and larger peak value of forward and backward partial pushing force. In the process of side-step cutting, football players are accustomed to stop in a sudden way with their forefeet touching, thus producing higher ground reaction force and increasing knee flexion angle to buffer, while having greater ankle valgus angle and knee rotation angle. Basketball players have smaller knee flexion angle in the process of side-step cutting. A smaller angle is not conducive to the lower limb joint to buffer the ground reaction force, and then increases the risk of anterior cruciate ligament injury. [ABSTRACT FROM AUTHOR]

Background: Numerous studies have investigated kinematic alterations in patients with an isolated anterior cruciate ligament (ACL) injury. However, a substantial proportion of patients with injured ACLs also have concomitant meniscal tears. Purpose: To evaluate the in vivo alteration of knee kinematics after an ACL tear, with or without a combined medial or lateral meniscal tear, during level walking activity. Study Design: Controlled laboratory study. Methods: Fifty-six patients with unilateral ACL-deficient (ACLD) knees were studied. Among these patients, 15 had isolated ACL injuries (group 1), 15 had combined ACL and medial meniscal injuries (group 2), 15 had combined ACL and lateral meniscal injuries (group 3), and 11 had combined ACL and medial/lateral meniscal injuries (group 4). The kinematics of each knee was determined using an optical tracking system during treadmill gait. Range of motion (ROM) and kinematic alterations were compared between the contralateral ACL-intact (ACLI) and ACLD knees. Results: All ACLD knees, with or without meniscal deficiency, had significantly less flexion than the ACLI knees (~3°-8°; P < .05). In groups 1, 3, and 4, the injured knees exhibited more femoral external rotation by approximately 1° to 2° (P < .05). Group 4 showed posterior femoral translation (anterior tibial translation) in the swing phase (~13 mm), while groups 2 and 3 showed increased anterior femoral translation (~2-3 mm). During medial-lateral translation, patients in group 2 had a more medial femoral shift (~4 mm) relative to the tibia initially, while those in group 4 exhibited a lateral femoral shift. Conclusion: The results indicate that meniscal injuries alter the kinematics of the ACLD knee when compared with knees with an isolated ACL injury. The location of the meniscal tear also affects knee kinematics. Clinical Relevance: Considering the varying effects of meniscal injuries on knee joint kinematics, these data provide insight into the pathological function of the ACL-injured knee joint during walking. [ABSTRACT FROM AUTHOR]

The article discusses a study conducted to explore the use and significance of neuromuscular training in preventing anterior cruciate ligament (ACL) injury in female athletes. Topics discussed include the use of electronic journal databases of "MEDLINE," "PubMed" and "CINAHL" for articles on ACL injury; incidences of ACL injury after neuromuscular training; and compliance. The study suggests the effectiveness of neuromuscular training in preventing ACL injury in female athletes.

The purpose of this study was to investigate in vivo threedimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial-lateral and proximaldistal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°. [ABSTRACT FROM AUTHOR]

The article discusses a study to evaluate and compare the short-term clinical outcome of surgical anterior cruciate ligament reconstruction (ACLR) with the remnant preservation technique as against standard ACLR. Participants included 90 patients that underwent ACLR. The findings revealed that remnant preservation ACLR was not found to be superior to standard ACLR in terms of stability, synovial coverage, and proprioception recovery and also was not superior in terms of clinical outcomes.

Background: Currently, there is an ongoing debate regarding the optimal graft choice between autograft and allograft tendons in reconstruction of the anterior cruciate ligament (ACL). It has been reported that allograft tendons have a slower onset and rate of revascularization compared with autograft tendons. Hypothesis: Allograft tendons might have inferior graft maturity compared with autograft tendons in ACL reconstruction at 2 years postoperatively. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 52 participants with ACL reconstruction were recruited in this study, including 30 using allograft tendons and 22 using autograft tendons. All of them had unilateral ACL reconstruction and were followed up using 3.0-T magnetic resonance imaging (MRI) at least 2 years postoperatively. Clinical examination was performed on the same day when the MRI examination was performed, including subjective functional examinations (International Knee Documentation Committee [IKDC] and Tegner Lysholm Knee Scoring Scale [TLKS]) and physical examinations (anterior drawer test and Lachman test). Four measurements based on MRI were focused on graft orientation (including tibial tunnel position and graft angles), the edematous condition of the graft, intra-articular graft width at different sites, and signal intensity of the ACL graft using the signal/noise quotient (SNQ) from a region of interest analysis. Differences in each measurement were compared between the allograft group and the autograft group. Results:All the participants returned to normal sports activities at the follow-up time point, as all of them acquired full functional strength and stability. There was no significant difference between the autograft and the allograft group with respect to IKDC or TLKS score. The knees in both of the groups were confirmed stable by physical examination before MRI. On MRI measurements, the allograft group displayed no significant difference in graft orientation compared with the autograft group (P > .05). Moreover, there was also no significant difference between allograft group and autograft group in graft width of the distal site (P > .05), middle site (P > .05), and proximal site (P > .05). However, the mean SNQ value of the allograft group was significantly higher than that of the autograft group in the distal site (6.54 ± 6.58 vs 2.98 ± 5.48; P = .0173), the middle site (7.21 ± 6.31 vs 3.56 ± 4.62; P = .0149), and the proximal site (6.61 ± 8.08 vs 2.45 ± 8.12; P = .0018). Conclusion: The allograft group had a significantly higher SNQ value compared with the autograft group in this study, indicating that allograft tendons might have inferior graft maturity than autograft tendons in ACL reconstruction at 2 years postoperatively. [ABSTRACT FROM AUTHOR]

Background: Nonanatomic transtibial single-bundle anterior cruciate ligament reconstruction (SB-ACLR) with a bone–patellar tendon–bone (BPTB) allograft has been used for a long time and has shown the same satisfactory clinical results as an autograft; however, it has not been reported if a double-bundle ACLR (DB-ACLR) could be performed with a BPTB allograft and achieve even better results.Hypothesis: The DB-ACLR with a BPTB allograft is technically feasible and will be superior to the SB technique in restoring better anterior and rotating stability.Study Design: Cohort study; Level of evidence, 2.Methods: The study was performed with 56 patients, and 52 (25 in the DB group and 27 in the SB group) of them were followed up at 2 to 5 years. With an irradiated deep-frozen BPTB allograft, a standard single-incision arthroscopic technique was used, and the graft was fixed with bioabsorbable interference screws on both the femoral and tibial sides. Outcome assessment at final follow-up included International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores; side-to-side difference by conventional KT-2000 arthrometer; total anteroposterior (AP) laxity by the back-pushing KT-2000 arthrometer; pivot shift (0, +, ++); range of motion (ROM); and isokinetic muscle strength evaluation.Results: Mean follow-up was 47.3 ± 11.5 and 58.2 ± 6.6 months for the DB group and SB group, respectively. A statistically significant difference in favor of the DB group was found with the total AP laxity at 30° (P < .05). The overall incidence of pivot shift in the DB group (4% ++) was significantly lower than that in the SB group (26%: 19% + and 7% ++; P = .029). No significant differences were found between the 2 groups in terms of IKDC score, Lysholm score, Tegner score, conventional KT-2000 arthrometer anterior laxity, ROM, and muscle strength.Conclusion: A DB-ACLR with a BPTB allograft is feasible and achieved more satisfactory results than the transtibial SB technique in terms of total AP stability and rotational stability in spite of no significant differences among other clinical parameters. [ABSTRACT FROM PUBLISHER]

Background: Little information is available regarding parameters that would enable a surgeon to predict the size and length of 4-stranded semitendinosus (ST) and 4-stranded gracilis tendon (GT) grafts.Purpose: To evaluate whether certain preoperative anthropometric data enable prediction of the size of 4-stranded ST and GT autograft for anterior cruciate ligament (ACL) reconstruction.Study Design: Cohort study (prevalence); Level of evidence, 2.Methods: This study involved 235 Chinese Han patients who underwent double-bundle ACL reconstruction with 4-stranded autogenous ST and GT grafts. Preoperatively, the authors recorded height, weight, body mass index (BMI), gender, age, and sports activity. During surgery, the usable length of the ST and GT and the diameter of the 4-stranded grafts made of ST and GT were measured. Multiple regression analysis was used to determine relationships between anthropometric measurements and the length and diameter of intraoperatively measured ST and GT grafts.Results: Strongest correlations for ST and GT length and GT graft diameter were height and weight. The strongest correlations for ST graft diameter were gender and weight. Body mass index had only moderate correlations with ST and GT graft size. Self-reported activity level was not correlated. Women had significantly smaller GT and ST graft diameters and shorter tendon lengths than did men. Semitendinosus graft size was significantly larger and longer than was the GT graft (7.4 ± 0.7 mm vs 5.9 ± 0.6 mm and 279.9 ± 20.8 mm vs 251.5 ± 20.8 mm, respectively). Simple regression analysis demonstrated that height, weight, and BMI can be used to predict ST and GT autograft length and diameter.Conclusion: Several preoperative anthropometric measurements showed correlation with the length of the ST and GT and diameter of 4-stranded ST and GT grafts. The current data may provide surgeons with important preoperative information about size of ST and GT grafts and would be useful for patient counseling and alternative graft source planning. [ABSTRACT FROM PUBLISHER]

Background: Most studies of allograft versus autograft for anterior cruciate ligament reconstruction have been of bone–patellar tendon–bone; outcome reports evaluating anterior cruciate ligament reconstruction with hamstring tendon autograft versus allograft are rare.Purpose: This study was undertaken to compare the clinical outcome of arthroscopic anterior cruciate ligament reconstruction with hamstring tendon autograft versus allograft.Study Design: Randomized controlled trial; Level of evidence, 2.Methods: Between 2000 and 2004, 208 patients who met the inclusion and exclusion criteria of the study were prospectively randomized into autograft (n = 104) or allograft (n = 104) groups. All hamstring tendon allografts were fresh-frozen and obtained from a single certified tissue bank. All the operations were done by the same surgeon with the same surgical technique. Femoral and tibial fixation was by means of an EndoButton and a bioabsorbable interference screw augmented with a staple, respectively. Patients were evaluated preoperatively and postoperatively. Evaluations included detailed history, physical examination, functional knee ligament testing, KT-2000 arthrometer testing, Harner vertical jump and Daniel 1-legged hop tests, Lysholm score, Tegner score, the International Knee Documentation Committee (IKDC) standard evaluation form, Cincinnati knee score, and radiographs.Results: Of these patients, 186 (autograft, n = 91; allograft, n = 95) were available for full evaluation. Demographic data were comparable between groups. The mean follow-up was 7.8 years for both groups. There were no statistically significant differences according to the evaluations of the outcome aforementioned between the 2 groups except that patients in the allograft group had a shorter operation time than the autograft group. Seven patients (7.7%) in the autograft group and 8 (8.4%) in the allograft group had a side-to-side difference >5 mm. Eighty-five patients (93.4%) in the autograft group and 86 (90.5%) in the allograft group were normal or nearly normal according to the overall IKDC. According to the subjective IKDC, the average scores were 89 and 90 points, respectively, for the autograft and allograft groups. The mean Lysholm and Tegner scores were 89 points and 7.7 points, respectively, for the autograft group and 90 points and 7.6 points, respectively, for the allograft group. For the Cincinnati knee score, the average scores were 90 and 91 points, respectively, for the autograft and allograft groups.Conclusion: Both groups of patients achieved almost the same satisfactory outcome at an average of 7.8 years of follow-up. Fresh-frozen hamstring tendon allograft is a reasonable alternative choice to autograft for anterior cruciate ligament reconstruction. [ABSTRACT FROM AUTHOR]

Background: The restoration of knee rotational stability after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction has been demonstrated in the cadaveric model and with passive stress tests on humans but not yet with dynamic functional biomechanical tests performed by human participants.Purpose: To prospectively investigate the range of tibial rotation of ACL-deficient and ACL-reconstructed knees during a pivoting task. The authors hypothesized that there would be a significant increase in tibial internal rotation in the ACL-deficient knee compared with the contralateral knee and that the increased rotation would return to normal after anatomic double-bundle ACL reconstruction.Study Design: Case series; Level of evidence, 4.Methods: Ten men with unilateral ACL injury performed a high-demand jump-landing and pivoting task before and after ACL reconstruction with mean follow-up of 11 months. The range of tibial rotation of the injured, reconstructed, and intact knees during the pivoting movement was measured by an optical motion analysis system. Paired t tests were performed to investigate any significant difference between the 2 limbs preoperatively and postoperatively and within the injured limb before and after the surgical treatment. Statistical significance was set at P < .05.Results: The range of tibial rotation was higher in the ACL-deficient knee (12.6° ± 4.5°) than in the intact knee (7.9° ± 3.1°) preoperatively (P < .05). The increased rotation was reduced in the reconstructed knee (8.9° ± 3.0°) after ACL reconstruction versus the intact knee postoperatively (8.2° ± 2.6°) (P < .05). There was no significant difference in the tibial rotation between the intact knee and the reconstructed knee postoperatively (P > .05).Conclusion: As assessed with a dynamic functional pivoting movement, the anatomic double-bundle ACL reconstruction successfully restores knee rotational stability from an impaired level. [ABSTRACT FROM AUTHOR]

Background: A special type of repairable meniscal lesion involving the peripheral attachment of the posterior horn of the medial meniscus is commonly associated with anterior cruciate ligament deficiency and is termed a ‘‘ramp lesion.’’ However, there are no previously published articles reporting the epidemiologic characteristics of ramp lesions.Hypothesis: The ramp lesion is a special type of medial meniscal tear with high prevalence associated with anterior cruciate ligament rupture; the prevalence increases with time from anterior cruciate ligament injury. Age and gender are risk factors affecting the prevalence of the ramp lesion.Study Design: Cross-sectional study; Level of evidence, 3.Methods: From April 2002 to October 2007, 868 consecutive knees were diagnosed as having an anterior cruciate ligament injury and received arthroscopic surgery for anterior cruciate ligament reconstruction. All the patients had verified tears of the ramp area under arthroscopy. The prevalence of the ramp lesion was evaluated retrospectively. Then, all cases were divided into different groups depending on the time interval from anterior cruciate ligament injury to anterior cruciate ligament reconstruction and other relevant risk factors such as age and gender. The effects of age, gender, and time from injury on the prevalence of ramp lesions were analyzed.Results: Among 868 knees that underwent surgery for anterior cruciate ligament reconstruction, 144 knees were diagnosed as having a ramp lesion. The mean age was 24.7 years; there were 113 male and 31 female patients. The mean time from injury to anterior cruciate ligament reconstruction was 27.2 months. The prevalence of ramp lesions was 16.6%, which was analyzed as a logarithmic correlation with time from injury. Patients younger than 30 years of age and male patients had a significantly higher prevalence of ramp lesions.Conclusion: The ramp lesion is a common meniscal injury that can occur at the time of anterior cruciate ligament rupture or as a result of knee laxity associated with anterior cruciate ligament insufficiency. The prevalence of ramp lesion in this patient group was 16.6%, which increased with time until 24 months after initial injury. Patients younger than 30 years of age and male patients had a higher prevalence of ramp lesions. [ABSTRACT FROM AUTHOR]