Knee Joint Stability Research Articles

Effect of foot strike patterns and angles on the biomechanics of side-step cutting

ObjectivesThe study aimed to determine how foot strike patterns and cutting angles affect lower extremity (LE) kinematics, kinetics, and muscle activity during side-step cutting.MethodsTwenty male college sport athletes participated in this research. Three-dimensional motion analysis featuring ground reaction force (GRF) and electromyography (EMG) of the dominant leg was used. LE kinematics, kinetics, and EMG data parameters were obtained during a 45° and 90° side-step cutting involving rearfoot strikes (RFS) and forefoot strikes (FFS).ResultsThe significant foot strike pattern × angle interactions were observed for the ankle eversion range of motion (ROM) at the loading phase. Cutting of 90° had greater knee flexion ROM, knee valgus ROM, and knee varus moment compared to that of 45°. RFS cutting had greater knee flexion, hip flexion, knee valgus, knee varus moment, knee varus moment, and ankle eversion ROM. FFS cutting produced a lower vertical GRF, lateral GRF, and a loading rate. Both vastus medialis and vastus lateralis muscle activities were remarkably greater during cutting of 90° than 45°. At the loading phase, semitendinosus, biceps femoris, and the lateral head of gastrocnemius muscle activities during FFS cutting were considerably greater than those during RFS cutting.ConclusionThe FFS pattern can better protect the anterior cruciate ligament (ACL) and improve the flexibility of athletes by increasing the plantarflexion torque of the ankle. The injury risk also increases with the larger cutting angle. The EMG activities of semitendinosus and biceps femoris are vital for the stability of knee joint during side-step cutting, which helps reduce ACL stress during buffering.

Research progress in repair and reconstruction of tumor-related bone defects in proximal femur

To review the repair and reconstruction methods for large segmental femoral proximal bone defects caused by tumors, and to explore their clinical application effects, advantages, and disadvantages, and future research directions. A comprehensive search of Chinese and foreign databases was conducted to select basic and clinical research literature related to the repair and reconstruction of femoral proximal bone defects caused by tumors. The studies were classified and analyzed based on two main strategies: hip-preserving reconstruction and non-hip-preserving reconstruction. In hip-preserving reconstruction, traditional methods such as allograft transplantation and vascularized autograft transplantation are common but have risks of poor bone integration and bone resorption. The clinical application of inactivated tumor segment reimplantation and distraction osteogenesis techniques is limited. In recent years, three-dimensional printing technology has become increasingly mature, with personalized prostheses and precise surgeries becoming development trends. Non-hip-preserving reconstruction primarily includes allograft prosthesis composite and total femoral replacement. The former focuses on improving the survival rate and bone integration efficiency of the allograft, while the latter requires the simultaneous reconstruction of hip and knee joint stability. Significant progress has been made in repairing and reconstructing proximal femoral bone defects caused by tumors, but many challenges remain. The integration of three-dimensional printing technology and digital design offers potential for precise bone defect repair. Future efforts should focus on new concepts, technologies, and materials through multidisciplinary approaches to provide personalized and precise solutions, thereby improving patient quality of life.

High-load strength training compared with standard care treatment in young adults with joint hypermobility and knee pain: study protocol for a randomised controlled trial (the HIPEr-Knee study)

IntroductionPatients with generalised joint hypermobility, including knee hypermobility (GJHk), often experience knee pain and are typically managed with low-intensity strength training and/or proprioceptive training as part of standard care. However,...

Soft tissue elasticity in total knee arthroplasty: An in vivo quantitative analysis

BackgroundSoft tissue balance is essential for total knee arthroplasty success. The elastic properties of soft tissues affect knee-joint stability and flexibility. This study proposed a novel methodology for in vivo quantitative analysis of soft tissue elasticity during total knee arthroplasty. In this study, we aimed to (1) establish a mathematical model to depict medial and lateral soft tissue elasticity, (2) report the individual differences and interindividual commonalities in soft tissue elasticity. MethodsA specifically designed knee tensor was used to evaluate soft tissue elasticity by dynamically applying sequential tensions to medial and lateral compartments while measuring knee joint gaps in both compartments. Measurements were performed on ten knees of six cadavers. Bivariate polynomial regression was used for analysis, and the equivalent elastic coefficient (N/mm) was calculated. FindingsSoft-tissue elasticity showed high individual differences. The equivalent elastic coefficient was larger in the medial compartment than in the lateral compartment, and the equivalent elastic coefficient of the lateral compartment gradually decreased while the medial equivalent elastic coefficient remained constant when the knee was flexed. The lateral gaps increased from 0.1 to 3.9 mm, and the medial gaps increased from 0 to 1.5 mm when the tension increased from 60 to 90 N. The shapes and distributions of the silkworm-like lattices in elasticity and balance evaluations are clinically relevant to knee balance. InterpretationSoft-tissue balance in total knee arthroplasty is significantly affected by soft-tissue elasticity. An intraoperative quantitative analysis of elasticity helps to tail an individualized balancing target for total knee arthroplasty.

Quadriceps angle as an outcome measure for structural integrity following total knee arthroplasty in individuals with severe knee osteoarthritis

PurposeTotal knee arthroplasty (TKA) is routinely performed for pain relief and to improve performance of the knee in individuals with severe knee osteoarthritis (OA). The quadriceps angle (Q-angle) is a key component of knee joint stability. However, there is a dearth of literature evaluating Q-angle as an outcome measure after TKA in individuals with severe knee OA. ObjectivesThe objective of the study was to assess the Q-angle as an outcome measure before and after TKA and to find the correlation of Q-angle with pain, quadriceps strength, and knee flexion range of motion (ROM) after TKA in individuals with severe knee OA. MethodsThe Q-angles of 34 individuals (male: female = 17:17) were measured using standardized procedures. Pain, quadriceps strength, and knee flexion ROM were measured. The measurements were taken preoperatively (one day before surgery), and postoperatively at the sixth week and third month after TKA. ResultsThe mean Q-angle was 19.17° (SD = 1.92°) before TKA, 16.06° (SD = 1.87°) at the sixth week and 13.43° (SD = 1.77°) at the third month after TKA. Significant linear correlations were noted between the Q-angle and pain, quadriceps strength, and knee flexion ROM following TKA. ConclusionThe Q-angle was measured before and after TKA using a standardized clinical goniometric method. Understanding the Q-angle before and after TKA and its relationship with various clinical and functional variables is imperative in clinical practice for orthopedic surgeons and rehabilitation professionals.

A machine learning system for artificial ligaments with desired mechanical properties in ACL reconstruction applications

The anterior cruciate ligament is one of the important tissues to maintain the stability of the human knee joint, but it is difficult for this ligament to self-heal after injury. Consequently, transplantation of artificial ligaments (ALs) has gained widespread attention as an important alternative treatment method in recent years. However, accurately predicting the intricate mechanical properties of ALs remains a formidable challenge, particularly when employing theoretical frameworks such as braiding theory. This obstacle presents a significant impediment to achieving optimal AL design. Therefore, in this study, a high-precision machine learning model based on an artificial neural network was developed to rapidly and accurately predict the mechanical properties of ALs. The results showed that the proposed model achieved a reduction of 45.22% and 50.17% in the normalized root mean square error on the testing set when compared to traditional machine learning models (Random Forest and Support Vector Machine), demonstrating its higher accuracy. In addition, the design of ALs with desired mechanical properties was achieved by optimizing the braiding parameters, and its effectiveness was verified through experiments. The mechanical properties of the prepared ALs were able to fully meet the desired targets and were at least 2% higher. Finally, the influence weights of different braiding parameters on the mechanical properties of ALs were analyzed by feature importance.

Domain-Adaptive Framework for ACL Injury Diagnosis Utilizing Contrastive Learning Techniques

In sports medicine, anterior cruciate ligament (ACL) injuries are common and have a major effect on knee joint stability. For the sake of prognosis evaluation and treatment planning, an accurate clinical auxiliary diagnosis of ACL injuries is essential. Although existing deep learning techniques for ACL diagnosis work well on single datasets, research on cross-domain data transfer is still lacking. Building strong domain-adaptive diagnostic models requires addressing domain disparities in ACL magnetic resonance imaging (MRI) from different hospitals and making efficient use of multiple ACL datasets. This work uses the publicly available KneeMRI dataset from Croatian hospitals coupled with the publicly available MRnet dataset from Stanford University to investigate domain adaptation and transfer learning models. First, an optimized model efficiently screens training data in the source domain to find unusually misclassified occurrences. Subsequently, before being integrated into the contrastive learning module, a target domain feature extraction module processes features of target domain samples to improve extraction efficiency. By using contrastive learning between positive and negative sample pairs from source and target domains, this method makes domain adaptation easier and improves the efficacy of ACL auxiliary diagnostic models. Utilizing a spatially augmented ResNet-18 backbone network, the suggested approach produces notable enhancements in experimentation. To be more precise, the AUC for transfer learning improved by 3.5% from MRnet to KneeMRI and by 2.5% from KneeMRI to MRnet (from 0.845 to 0.870). This method shows how domain transfer can be used to improve diagnostic accuracy on a variety of datasets and effectively progresses the training of a strong ACL auxiliary diagnostic model.

Effects of combining rehabilitation training on the recovery of athletic ability after reconstruction of injured ligament

This paper aims to investigate the impact of conventional rehabilitation training and neuromuscular electrical stimulation (NMES) on the recovery of motor abilities in patients following ligament injury reconstruction. Forty postoperative patients who underwent surgery for anterior cruciate ligament reconstruction (ACLR) were randomly allocated to either the conventional rehabilitation group or the NMES group. The NMES group received NMES treatment in addition to the conventional rehabilitation program starting from eight weeks postoperatively. Various parameters, including knee joint function, stability, and balance, were compared between the two groups at eight weeks and 12 weeks postoperatively. Compared to the data at eight weeks postoperatively, both groups exhibited significant improvements in all measured indicators at 12 weeks postoperatively (p < 0.05). In the 12th week after the surgery, the NMES group demonstrated a Lysholm score of 93.18 ± 3.67 points, an IKDC score of 84.65 ± 2.33 points, a KT-2000 measurement of 0.88 ± 0.45 mm, a thigh circumference difference of −1.33 ± 0.55 cm, a knee flexion angle of 130.12 ± 4.21°, a single-leg standing time of 60.12 ± 9.33 s, a YBT score of 70.26 ± 2.68 points, and a Bulgarian split squat 1RM size of 58.07 ± 6.85 kg; all of these results were significantly superior to those observed in the conventional group (p < 0.05). NMES significantly enhances the recovery of athletic ability in patients following postoperative ACLR and can be effectively applied in clinical practice.

The application of proximal tibial anterior closing wedge osteotomy in anterior cruciate ligament reconstruction

IntroductionPosterior tibial slope (PTS) plays a vital role in knee stability. PTS of more than 12° may be considered with increased strain on the native anterior cruciate ligament (ACL) fibers. To handle the instability caused by changes in PTS degree, Proximal Tibial Anterior Closing Wedge Osteotomy (PT-ACWO) is adopted by surgeons. MethodsBetween October 2015 and October 2019, our department conducted a retrospective analysis of patients who experienced anterior cruciate ligament reconstruction (ACLR) graft failures, with a particular focus on pathological PTS. The time from initial ACLR to revision ranged from 1 to 10 years, with a mean of 2.5 years. Radiological assessments of PTS were conducted, and outcomes were quantified using the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale. The surgical technique and the use of 3D Patient-Specific Instrumentation (PSI) were outlined. Preoperative imaging included the use of Kirschner wires to establish tibial plateau reference points, and 3D-PSI was employed to guide the location and depth of the tibial osteotomy, which was performed obliquely. In a notable instance, a novel tibial tunnel was mapped out, and ortho-bridge system (OBS) fixation was utilized to ensure adequate space for the new tunnel. ResultsIn a cohort of seven patients with a mean follow-up of 28.1 months, a significant reduction in PTS was noted postoperatively (median [interquartile range, IQR], from 15.27° [13.46°, 16.60°] to 6.25° [5.89°, 6.78°]; P = 0.002). IKDC score improved to 85.10 (80.25, 88.10), P < 0.001; the Lysholm score to 88.00 (73.00, 90.50), P < 0.001; and the Tegner score to 8.00 (7.20, 8.05), P = 0.025 at final follow-up. Skin incision healing delays occurred in two instances, yet achieved closure by six weeks. Radiographs at three months demonstrated faster bone healing in oblique osteotomies than transverse ones. Knee joint stability was maintained, with no additional complications or evidence of instability noted. Magnetic resonance imaging (MRI) confirmed graft integrity in all patients, without signs of enlargement or mispositioning at last observation. ConclusionAn augmented PTS angle exceeding 12 may constitute a potential etiology for the failure of ACLR grafts. In such patients, the implementation of ACLR combined with PT-ACWO could mitigate the risk of surgical failure during initial ACLR or subsequent revision procedures.

Effect of different degrees of primary varus knee on short-term effectiveness of anterior cruciate ligament reconstruction

To investigate whether different degrees of primary varus knee affect joint function and stability in patients undergoing anterior cruciate ligament (ACL) reconstruction. A clinical data of 160 patients with primary varus knee, who were admitted between January 2020 and December 2021 and met the selection criteria, was retrospectively analyzed. All patients underwent primary ACL reconstruction using autologous single-bundle hamstring tendon. Patients were divided into three groups based on the hip-knee-ankle angle (HKA): group A (64 patients with HKA 0°-3°), group B (55 patients with HKA 3°-6°), and group C (41 patients with HKA 6°-9°). Except for the significant difference in HKA among the three groups ( P<0.05), baseline data such as age, gender, affected side, body mass index, interval between injury and operation, Kellgren-Lawrence grading, posterior tibial slope, proportion of combined meniscal injuries, Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) objective score, anterior drawer test, Lachman test, pivot shift test, and the results of KT1000 (side-to-side difference, SSD) showed no significant difference ( P>0.05). At last follow-up, joint stability was assessed through the anterior drawer test, Lachman test, pivot shift test, and SSD; joint function was evaluated using the Tegner score, Lysholm score, and IKDC objective score. All incisions in the three groups healed by first intention after operation. All patients were followed up 24-31 months, with an average of 26 months; there was no significant difference in the follow-up time among the three groups ( Z=0.675, P=0.714). At last follow-up, the knee stability and functional assessment indicators in each group significantly improved when compared to preoperative ones ( P<0.05); there was no significant difference among the three groups ( P>0.05) in terms of the anterior drawer test, Lachman test, pivot shift test, IKDC objective scores, and the changes of the Lysholm scores and Tegner scores. The Kellgren-Lawrence grading and HKA at last follow-up were consistent with preoperative results in the three groups. Varying degrees of primary varus knee do not affect early knee joint stability and functional recovery after ACL reconstruction, and there is no significant difference in effectiveness between different degrees of varus knee.

Development and clinical validation of a deep learning-based knee CT image segmentation method for robotic-assisted total knee arthroplasty.

This study aimed to develop a novel deep convolutional neural network called Dual-path Double Attention Transformer (DDA-Transformer) designed to achieve precise and fast knee joint CT image segmentation and to validate it in robotic-assisted total knee arthroplasty (TKA). The femoral, tibial, patellar, and fibular segmentation performance and speed were evaluated and the accuracy of component sizing, bone resection and alignment of the robotic-assisted TKA system constructed using this deep learning network was clinically validated. Overall, DDA-Transformer outperformed six other networks in terms of the Dice coefficient, intersection over union, average surface distance, and Hausdorff distance. DDA-Transformer exhibited significantly faster segmentation speeds than nnUnet, TransUnet and 3D-Unet (p<0.01). Furthermore, the robotic-assisted TKA system outperforms the manual group in surgical accuracy. DDA-Transformer exhibited significantly improved accuracy and robustness in knee joint segmentation, and this convenient and stable knee joint CT image segmentation network significantly improved the accuracy of the TKA procedure.

PARAMETERS OF THE INTERCONDYLAR FOSSA OF THE FEMUR IN CHILDRENIN NORMAL CONDITIONS AND WITH CONGENITAL MALFORMATIONS OF THE LOWER LIMBS

According to literature sources, radiography can indirectly visualize congenital insufficiency of the cruciate ligaments both in isolated form and in combination with other congenital malformations of the lower extremities. Objective. To study the parameters of the intercondylar fossa of the femur in children of different age groups with stable/unstable knee jo ints due to congenital malformations of the lower limbs using instrumental imaging methods. Methods. A prospective diagnostic study was conducted of 359 knee joints of 217 children who were treated at the pediatric orthopedics clinic from 2019to 2022 and with a retrospective control group (2010–2021). limbs, as well as with congenital malformations of the lower limbs. X-ray examinations were performed on the OPERA T90cex X-ray and fluoroscopic system. Results. 217 patients took part in the study, including 105 patients without knee jointpathology and 112 with congenital malformations of the lower limbs. Comparison of the accuracy of radiological diagnostic indicators was performed using the Studentʼs t-test with the results of computer and magnetic resonance imaging studies, which showed the absence of a statistically significant differencein the results research. A diagnostic study was also conducted to find the regularity of the development of the knee joints and to identify the parameters of the radiological norm of the development of the intercondylar fossa of the femur in children of different age categories. Conclusions. Using the resultsof instrumental studies, the parameters of the intercondylar fossa of the femur in children of different age categories with stable and unstable knee joints due to congenital malformations of the lower limbs were investigated. The results of the study should be taken into account for the diagnosis of congenital defects of the knee joint.

Peroneus longus tendon autograft for one-stage revision acl reconstruction: mid-term results

Background. The results of revision anterior cruciate ligament reconstruction (ACLR) are usually worse than the primary ACLR. The positive outcome of the revision ACLR is significantly influenced by the following factors: anatomical position of bone tunnels, correct choice of graft, its preparation and fixation method. Equally important is to choose the accurate indications for additional extraarticular interventions. The aim of the study is to evaluate the role of a peroneus longus tendon (PLT) autograft in one-stage revision ACL reconstruction and to compare the obtained data with the results of primary ACLR. Methods. The comparison was carried out between the RACL-PLT group (n = 29) and the PACL-HT group (n = 82), which underwent single-stage revision ACLR with a PLT autograft and primary ACLR with a hamstring tendons (HT) autograft, respectively. Subjective and objective evaluation was performed on the KOOS, IKDC, and Lysholm Knee scales. Also, in the RACL-PLT group, the position of the central entry points into the primary and revision tunnels was determined. Results. We observed no statistically significant differences during the objective assessment of knee joint stability between the groups (p0.999). During the subjective assessment on the KOOS, IKDC and Lysholm Knee scales, significantly higher results were obtained in the PACL-HT group (p0.001). The position of the central entry points into the revision tunnels corresponded to the normative values in all cases. Conclusions. The analysis of the use of a PLT autograft in revision ACLR, as well as the achievement of the anatomical position of the revision tunnels showed: 12 months after surgery, the results of an objective assessment between the revision and primary ACLR are comparable; the results of a subjective assessment are statistically significantly different. However, the differences in indicators do not reach a minimal clinically important difference.

Clinical Outcomes of Modified Suture Buttons for Tibial Side Fixation in Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Study.

Introduction Restoring knee joint stability and resuming sports activities are important objectives of anterior cruciate ligament (ACL) reconstruction. The maintenance of anterior knee stability after ACL reconstruction is contingent on graft tension. Various devices and techniques have been used to achieve robust tibial graft tendon fixation, and their advantages and disadvantages are established. However, a gold standard has not been established. Therefore, we aimed to determine whether anterior knee joint stability and clinical outcomes of graft tendon fixation could be improved using a recently modified suture button (MSB) compared with using an adjustable suspensory fixator (ASF) at 1 year after double-bundle ACL reconstruction. Methods This study retrospectively analyzed postoperative data derived from 79 patients at a single center between January 2016 and December 2021. The patients were assigned to groups that underwent double-bundle ACL reconstruction with tibial fixation using an MSB (n = 30) that maintains tension while tying sutures, or an ASF (n = 49). We then compared complications, clinical outcomes and knee joint stability at 1 year postoperatively. Rates of postoperative infection, graft rupture, implant removal and residual anterior knee laxity (AKL) were compared between the groups using chi-square tests. Patient-reported outcome measures (PROM) based on Forgot Joint Score-12, Knee Injury and Osteoarthritis Outcome, and Lysholm Knee scoreswere compared using Mann-Whitney U tests. Results One patient in the MSB group developed postoperative infection. Rates of graft rupture and implant removal in the MSB and ASF groups were 3.3% and 4.1%, and 3.6% and 10.2%, respectively. None of the PROMs differed between the groups. The proportions of postoperative AKL were 3.6% and 14.9% in the MSB and ASF groups, respectively. A trend towards lower postoperative AKL in the MSB group did not reach statistical significance (p = 0.25). Conclusions The incidence of AKL at a year after ACL reconstruction using the MSB was 3%. Postoperative AKL and clinical outcomes were comparable between the MSB and ASF groups. A low AKL rate and positive postoperative outcomes indicated that MSB could be an option for tibial-side fixation in ACL reconstruction.

Combined articular and ligament reconstructions in neglected fracture-dislocation of the knee

BackgroundThe management of neglected traumatic knee dislocations is challenging and is commonly associated with suboptimal outcomes. In this article we present two cases of neglected knee dislocations in two young trauma victims who presented late due to restrictions during the COVID-19 pandemic. MethodsTwo young patients presented at our center with neglected knee fracture-dislocations after eight weeks and six months of trauma. Comprehensive evaluation was performed using radiographs, computed tomography scans, and magnetic resonance imaging. Surgical intervention included open reduction and internal fixation of the mal-aligned intra-articular fracture fragments. Additionally, articular congruency was restored and repair or reconstruction of the posterior cruciate ligament, anterior cruciate ligament, and meniscus was conducted using suitable tendinous autografts and implants. Following surgery, the knees were immobilized for six weeks, followed by aggressive physical therapy. ResultsAfter three months of surgical intervention, fracture union and joint stability were achieved. At the >36-month follow-up appointments, both patients were pain-free at rest with a stable knee joint, achieving ≥90 degrees of knee flexion and without extensor deficits. Concurrent with radiographic evidence of osteoarthritic changes in the knee joint, there was mild pain (VAS 2) after prolonged knee movement activities and walking for long distances (>1 km). ConclusionOpen reduction and internal fixation, along with simultaneous menisco-ligamentous reconstructions in neglected fracture-dislocations of the knee result in satisfactory clinical outcomes. This approach proves to be an effective joint preservation procedure in young patients, even in delayed and neglected conditions.

The Effect of Gracilis Tendon Preservation on Postoperative Knee Joint Stability and Muscle Strength in Arthroscopic Anterior Cruciate Ligament Reconstruction Surgery.

The aim of our study is to evaluate preserving gracilis tendon in anterior cruciate ligament reconstruction (ACLR) surgery and its effect to the flexion of the knee joint and tibial internal rotation strength and the stability of the knee. Patients who underwent primary single-bundle arthroscopic ACLR using all-inside technique and using hamstring tendon autograft were evaluated retrospectively. Patients were divided into two groups as gracilis preserved (St) and gracilis harvested (StG) groups. The International Knee Documentation Committee (IKDC) score, Lysholm, Knee Injury and Osteoarthritis Outcome Score-Knee-related quality of life (KOOS-QOL) score, ACL-Return to Sport after Injury scale score were used to evaluate as postoperative functional scores at last follow-up. Anterior tibial translation was evaluated using the KT-1000 device. Knee joint flexion, extension, and internal rotation strength were evaluated using isokinetic dynamometer. Dynamic balance performances were measured using the Biodex Balance System. There were 24 patients in the St group and 23 patients in the StG group. Demographic data and clinical results showed no significant difference. Anteroposterior movement of the tibia was found to be significantly higher in the StG group than in the St group in measurements at 89 and 134 N, respectively (p = 0.01 and <0.001). No statistically significant difference was found between both standard and deep flexor and extensor and internal rotator strength. No statistically significant difference was found in the amount of total, anteroposterior, and mediolateral balance deficit between the two groups. Additional gracilis harvesting does not have a negative effect on both standard and deep knee flexion, and tibial internal rotation strength compared with the St group. Although semitendinosus and StG group showed significantly more anterior tibial translation, there was no significant difference in clinical and dynamic stability measurements.

Comparison of the biomechanical properties of grafts in three anterior cruciate ligament reconstruction techniques based on three-dimensional finite element analysis

ObjectiveTo evaluate the biomechanical characteristics of grafts from three different anterior cruciate ligament (ACL) reconstructive surgeries and to determine which method is better at restoring knee joint stability.MethodsA 31-year-old female volunteer was enrolled in the study. According to the magnetic resonance imaging of her left knee, a three-dimensional model consisting of the distal femur, proximal tibia and fibula, ACL, posterior cruciate ligament, medial collateral ligament and lateral collateral ligament was established. Then, the ACL was removed from the original model to simulate the knee joint after ACL rupture. Based on the knee joint model without the ACL, single-bundle ACL reconstruction, double-bundle ACL reconstruction, and flat-tunnel ACL reconstruction were performed. The cross-sectional diameters of the grafts were equally set as 6 mm in the three groups. The bone tissues had a Young’s modulus of 17 GPa and a Poisson’s ratio of 0.36. The ligaments and grafts had a Young’s modulus of 390 MPa and a Poisson’s ratio of 0.4. Six probes were placed in an ACL or a graft to obtain the values of the equivalent stress, maximum principal stress, and maximum shear stress. After pulling the proximal tibia with a forward force of 134 N, the distance that the tibia moved and the stress distribution in the ACL or the graft, reflected by 30 mechanical values, were measured.ResultsThe anterior tibial translation values were similar among the three groups, with the double-bundle ACL reconstruction group performing the best, followed closely by the patellar tendon ACL reconstruction group. In terms of stress distribution, 13 out of 30 mechanical values indicated that the grafts reconstructed by flat bone tunnels had better performance than the grafts in the other groups, while 12 out of 30 showed comparable outcomes, and 5 out of 30 had worse outcomes.ConclusionCompared with traditional single-bundle and double-bundle ACL reconstructions, flat-tunnel ACL reconstruction has advantages in terms of stress dispersion. Additionally, flat-tunnel ACL reconstruction falls between traditional double-bundle and single-bundle ACL reconstructions in terms of restoring knee joint stability and is superior to single-bundle ACL reconstruction.

THE EFFECTIVENESS OF KNEE BRACES IN CEREBRAL PALSY PATIENTS: A CASE STUDY

This case study examines the effectiveness of knee braces in aiding people with cerebral palsy (CP) in standing. The study focuses on a young boy with CP who struggled with standing due to muscle weakness and stiffness. Custom knee braces were prescribed and fitted as part of the operation to provide external support and stability to the knee joints. The child's standing abilities were assessed before and after the braces were put on. Results showed that the child's standing ability and functional independence significantly improved after using knee braces. This improved knee joint stability and alignment allowed the child to engage more actively in everyday activities and social interactions, resulting in a more regulated and prolonged standing posture. The study underscores the importance of customized therapies and individualized evaluation for optimal functional results in CP patients. Keywords: Knee braces, cerebral palsy, spasticity, knee contracture, rehabilitation, neurodevelopment disorder, standing abilities.

Impact of Surgical Timing on Functional Outcomes after Anterior Cruciate Ligament Reconstruction.

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Estimating the Reliability and Validity of the Quadrant Hop Test in the Assessment of the Functional Stability of the Knee.

Background Many sporting activities demand multidirectional skills and movements, emphasizing the importance of various fitness components such as functional stability, strength, power, endurance, and range of motion. These aspects must be thoroughly assessed before athletes can return to sports safely following an injury. Although the single-leg hop test (SHT) is widely used as the gold standard for evaluating joint stability, it has limitations in assessing multidirectional movements. Therefore, further research is necessary to explore whether increasing the dynamicity of the hop test in different directions enhances its sensitivity in assessing knee joint stability across all four directions. The objective of this study was to investigate the applicability of a new functional assessment tool, the quadrant hop test (QHT), for evaluating lower limb functional stability. Methodology One hundred nineteen amateur sportsmen who are in the age group of 18-25 years with a limb symmetry index of the lower limb calculated through SHT of >80% were included. All the participants performed the SHT, a triple hop test (THT), a crossover hop test (CHT), and the QHT on two different days, with two investigators assessing the QHT on different days and then recording the measurements of Hop distance. Results The mean difference between SHT, THT, and CHT with QHT was 4.59%, with a moderate correlation between all the hop tests. The Cronbach's alpha revealed good intra-rater (0.917) and inter-rater reliability (0.912) of the QHT. Conclusion The QHT proves to be a reliable and valid measure for assessing the functional stability of the lower limb and is 4.59% more sensitive than SHT, THT, and CHT in assessing knee stability and in return to sports criteria.