Major Ligaments Research Articles

Anterior Cruciate Ligament Mechanical Response to Load in the Setting of Changes to the Medial Meniscus

The anterior cruciate ligament (ACL) is a major ligament in the knee joint, and its function is crucial for both the movement and stability of the knee. Our research takes a novel approach by investigating the effect of meniscus tears on the ACL, how such tears will impact the stress on the ACL, and its overall compensation in response to the changes in the meniscus. Hypothesis/Purpose: This study aims to investigate how the ACL compensates for the change in knee joint stability and contact pressures due to partial horizontal cleavage tears (HCTs) in the meniscus, such as partial meniscectomy and partial transplantation on knee joint stability and contact pressures. We hypothesize that HCTs will increase contact pressures and decrease joint stability, thereby inducing compensatory stress on the anterior cruciate ligament (ACL). Method: Seven freshly frozen human cadaveric knees were used in a study to investigate the effects of different meniscal conditions and surgical interventions on the meniscus itself. Four testing scenarios were established: intact knees, knees with partial horizontal cleavage tears (HCTs) of the meniscus, knees with partial meniscectomy, and knees with partial transplantation. Axial loading was applied, and the medial meniscus contact pressures were measured at 0° and 30° of flexion. Additionally, a mathematical 3D finite element model was created to evaluate the behavior of the ACL under different meniscus scenarios, which could not have been measured experimentally. Results: ACL contact pressure and stress analysis across various meniscal conditions demonstrated substantial variability. Horizontal cleavage tears (HCTs) resulted in heightened contact pressures and diminished joint stability, as evidenced by increased ACL stress attributed to compensatory mechanisms in the presence of meniscal tears. Conversely, transplantation procedures exhibited a mitigating effect, maintaining joint mechanics closer to intact conditions and minimizing alterations in ACL forces. These trends persisted at 30 degrees of knee flexion, where significant increases in ACL forces were observed in partial and complete HCT conditions. Conclusions: This study uncovers the biomechanical impacts of meniscal injuries, demonstrating how the ACL compensates for various meniscus conditions. In contrast, transplantation and repair conditions only slightly increase the stress on the ACL, putting much less strain on the ACL and supporting structures of the knee joint than an unrepaired tear.

Effect of Age on the Biomechanical Properties of Porcine LCL

The Lateral Collateral Ligament (LCL), one of the four major ligaments in the knee joint, resides on the outer aspect of the knee. It forms a vital connection between the femur and the fibula. The LCL’s primary role is to provide stability against Varus forces, safeguarding the knee from undue rotation and tibial displacement. Uniaxial mechanical testing was conducted on the dog bone (DB) samples in this study. The porcine of different ages, from 3 months to 48 months (4 years) old, were used to analyse the effect of age. A constant head speed of 200 mm/s was applied throughout the tests to mimic strain–stress and damage responses at an initial strain rate of 13.3/s. The mechanical properties of LCL were evaluated, with a specific focus on the effect of age. The LMM (Linear Mixed Model) analysis revealed a marginally significant positive slope for Young’s modulus (p = 0.0512) and a significant intercept (p = 0.0016); for Maximum Stress, a negative slope (p = 0.0346) and significant intercept (p < 0.0001); while Maximum Stretch showed a significant negative slope (p = 0.0007) and intercept (p < 0.0001), indicating the muscle reduces compliance and load-bearing capacity with age.

The Role of a New Hinged Total Knee Arthroplasty System for Use in a Variety of Complex Knee Scenarios: A Case Series.

Hinged knee arthroplasties are commonly used in scenarios where there are major ligament deficiencies or bone loss around the knee. They are applicable in native knees with major deformities and during revisions. They can also be used as a salvage procedure after distal femoral resection. The new modular hinged device system, namely the Triathlon Hinge Knee (THK) System (Stryker, Mahwah, New Jersey), reflects the advancements of third-generation design and enhances surgical flexibility by allowing streamlined integration with the Triathlon Total Stabilized (TS) System (Stryker, Mahwah, New Jersey) and the Global Modular Replacement System (GMRS, Stryker, Mahwah, New Jersey). Additionally, the Triathlon Revision Tibial Baseplate (Stryker, Mahwah, New Jersey) has been launched as part of THK and is compatible with the Modular Rotating Hinge (MRH , Stryker, Mahwah, New Jersey) femur, which allows the Revision Baseplate to replace the existing tibial component while leaving the existing MRH Femoral Component in place. The Triathlon Revision Tibial Baseplate enables orthopaedic surgeons to use constrained or hinged prostheses, including both distal and total femoral replacement options, without changing the Tibial Baseplate. This is because the TS, MRH, THK, and GMRS femurs are compatible with the new Triathlon Revision Tibial Baseplate. Additionally, the system can be augmented with metaphyseal cone constructs to help provide a stable foundation for reconstruction. This report explores the application of a new modular hinged device system in various scenarios, starting with (1) complex primary hinged knee arthroplasty, followed by revision hinged knee arthroplasty cases including (2) failed TKA with medial collateral ligament (MCL) dysfunction, (3) severe arthrofibrosis post-TKA, (4) revisions for prosthetic joint infection, (5) extensor mechanism deficiency, and (6) arthrofibrosis with extensor mechanism disruption, concluding with a case of (7) distal femoral arthroplasty for periprosthetic fracture post-failed TKA.

Acute Knee Injury Detection with Magnetic Resonance Imaging (MRI)

The anterior cruciate ligament (ACL) is a major ligament in the knee that helps to stabilize the joint and prevent excessive forward movement of the shinbone. An ACL tear is a common injury, especially among athletes who participate in sports that involve pivoting and sudden changes in direction. This paper proposes an ensemble model, which includes three deep learning models (EfficientNet-B7, ResNet-152V2, and DenseNet-201) and a genetic algorithm, to detect and classify ACL tears using knee magnetic resonance imaging (MRI). The ensemble model was trained on the KneeMRI dataset, which comprises labeled MRI images. The deep learning models can learn to identify subtle changes in ligament structure and signal intensity that are associated with ACL tears and the genetic algorithm is used to find the optimal prediction. The proposed ensemble model was evaluated using the KneeMRI dataset. The dataset was preprocessed using data augmentation techniques. Then, the ensemble model was applied to the KneeMRI dataset, evaluated, and compared with previous models. The accuracy, recall, precision, specificity, and F1 score of our proposed ensemble model were 99.68%, 98.73%, 99.52%, 99.62%, and 98.94%, respectively. Thus, our ensemble model has an unrivaled perceptive outcome and could be used to accurately identify and classify ACL tears, improving patient outcome.

Overstrain on the longitudinal band of the cruciform ligament during flexion in the setting of sandwich deformity at the craniovertebral junction: a finite element analysis

BACKGROUND CONTEXTIn the setting of “sandwich deformity” (concomitant C1 occipitalization and C2–3 nonsegmentation), the C1–2 joint becomes the only mobile joint in the craniovertebral junction. Atlantoaxial dislocation develops earlier with severer symptoms in sandwich deformity, which has been hypothesized to be due to the repetitive excessive tension in the ligaments between C1 and C2. PURPOSETo elucidate whether and how the major ligaments of the C1–2 joint are affected in sandwich deformity, and to find out the ligament most responsible for the earlier development and severer symptoms of atlantoaxial dislocation in sandwich deformity. STUDY DESIGNA finite element (FE) analysis study. METHODSA three-dimensional FE model from occiput to C5 was established using anatomical data from a thin-slice CT scan of a healthy volunteer. Sandwich deformity was simulated by eliminating any C0–1 and C2–3 segmental motion respectively. Flexion torque was applied, and the range of motion of each segment and the tension sustained by the major ligaments of C1–2 (including the transverse and longitudinal bands of the cruciform ligament, the alar ligaments, and the apical ligament) were analyzed. RESULTSTension sustained by the longitudinal band of the cruciform ligament and the apical ligament during flexion is significantly larger in the FE model of sandwich deformity. In contrast, tension in the other ligaments is not significantly changed in the sandwich deformity model compared with the normal model. CONCLUSIONSConsidering the importance of the longitudinal band of the cruciform ligament to the stability of the C1–2 joint, our findings implicate that the early onset, severe dislocation, and unique clinical manifestations of atlantoaxial dislocation in patients with sandwich deformity are mainly due to the enlarged force loaded on the longitudinal band of the cruciform ligament. CLINICAL SIGNIFICANCEThe enlarged force loaded on the longitudinal band of the cruciform ligament can add to its laxity and thus reducing its ability to restrict the cranial migration of the odontoid process. This is in accordance with our clinical experience that dislocation of the atlantoaxial joint in patients with sandwich deformity is mainly craniocaudal, which means severer cranial neuropathy, Chiari deformity, and syringomyelia, and more difficult surgical treatment.

Development of Multibundle Virtual Ligaments to Simulate Knee Mechanics After Total Knee Arthroplasty.

Preclinical evaluation of total knee arthroplasty (TKA) components is essential to understanding their mechanical behavior and developing strategies for improving joint stability. While preclinical testing of TKA components has been useful in quantifying their effectiveness, such testing can be criticized for lacking clinical relevance, as the important contributions of surrounding soft tissues are either neglected or greatly simplified. The purpose of our study was to develop and determine if subject-specific virtual ligaments reproduce a similar behavior as native ligaments surrounding TKA joints. Six TKA knees were mounted to a motion simulator. Each was subjected to tests of anterior-posterior (AP), internal-external (IE), and varus-valgus (VV) laxity. The forces transmitted through major ligaments were measured using a sequential resection technique. By tuning the measured ligament forces and elongations to a generic nonlinear elastic ligament model, virtual ligaments were designed and used to simulate the soft tissue envelope around isolated TKA components. The average root-mean-square error (RMSE) between the laxity results of TKA joints with native versus virtual ligaments was 3.5 ± 1.8 mm during AP translation, 7.5 ± 4.2 deg during IE rotations, and 2.0 ± 1.2 deg during VV rotations. Interclass correlation coefficients (ICCs) indicated a good level of reliability for AP and IE laxity (0.85 and 0.84). To conclude, the advancement of virtual ligament envelopes as a more realistic representation of soft tissue constraint around TKA joints is a valuable approach for obtaining clinically relevant kinematics when testing TKA components on joint motion simulators.

Cervical Spine Finite Element Models for Healthy Subjects: Development and Validation

Abstract Finite element modeling is a popular method for predicting kinematics and kinetics in spine biomechanics. With the advancement of powerful computational equipment, more detailed finite element models have been developed for the various spine segments. In this study, five detailed finite element models of the cervical spine are developed and validated. The geometric boundaries of the vertebrae are determined from computed tomography (CT) scans of five female subjects. The models include the C2–C7 vertebrae, intervertebral discs, nuclei, endplates, and five major ligaments (anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), ligamentum flavum (LF), interspinous ligament (ISL), and capsular ligament (CL)). The ligaments follow nonlinear stress–strain curves whereas all other parts adopt linear material properties. All the material properties are taken from existing literature. The mesh convergence test is performed under flexion/extension. For flexion/extension motion, a pure moment is applied at the top surface of the odontoid process of the C2 vertebra while nodes at the bottom surface of the C7 vertebra are fixed in all directions. The models are extensively validated in flexion/extension, lateral bending, and axial rotation against experimental and finite element studies in the literature. Intervertebral rotation and range of motion are studied under different loading conditions found in the literature. This research also investigates intersubject variability for the cervical spine among five finite element models from five different subjects. Predicted angular displacements and ranges of motion of the current models are consistent with the literature. The validated models are expected to be applicable to simulate neck-related trauma like whiplash and high-g acceleration, among other scenarios.

Management of Multiligament Knee Injury

Multiligament knee injuries are defined as injuries to at least two of the four major ligaments in the knee: anterior cruciate ligament, posterior cruciate ligament, lateral collateral ligament (and posterolateral corner) and medial collateral ligament (and posteromedial corner). Multiple ligament knee injuries that results from high energy trauma, may have nerve and vascular injuries, therefore neurovascular examination with clear documentation of capillary refill time, distal pulses, function of all lower limb compartments and common peroneal and tibial nerve function should be performed. Before definitive treatment performed, we have to classified the multiligament injury according to the energy of the injury and the anatomic injured structures. MRI still recommended to know about the ligaments injury. The goal and our priority treatment is to obtain functional stability of the knee without the loss of motion or stiffnes that can lead to longterm pain, weakness, and the subsequent osteoarthritis.

PHYSICAL THERAPY MANAGEMENT FOR POST OP ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION KNEE SINISTRA (A CASE STUDY)

The anterior cruciate ligament (ACL) is one of the four major ligaments that are important in stabilizing the knee joint. The ACL is easily at risk for injury, such as a rupture or tear. ACL occurs by contact or non-contact at the knee. Most injuries occur due to no-contact conditions almost 75% of cases. Mr. I was 16 years old on 2011 the patient injured his left knee while playing basketball. After that, there was so much pain around his left knee that he was unable to walk on his own. On October 29 2021, the patient underwent ACL and meniscus post-restructive surgery at the RSPI. After surgery, 1 week later the patient underwent physiotherapy at the Esa Unggul Sport Clinic, Jakarta. Patients undergo therapy four times in two weeks with a physiotherapy program that includes TENS, Quadriceps Set, Hamstring and Gastroc Stretching, Mobilization Exercises on the legs, Core exercise, Balance (passing ball), Exercises using Ankle. Patients were evaluated using antropometri, spygmomanometer, and goniometer. after 4 treatments the patient experienced a decrease in left knee edema, increased muscle mass, and increased contraction.

Biomechanical study of anterior and posterior pelvic rings using pedicle screw fixation for Tile C1 pelvic fractures: Finite element analysis.

The purpose of this study was to analyse the biomechanical characteristics of pedicle screws with different placement methods and diameters in the treatment of Tile C1 pelvic fractures by finite element simulation technology and to compare them with the plate fixation model to verify the effectiveness of pedicle screw fixation. A three-dimensional digital model of a normal pelvis was obtained using computed tomography images. A finite element model of a normal pelvis containing major ligaments was built and validated (Model 1). Based on the verified normal pelvis finite element model, a Tile C1 pelvic fracture model was established (Model 2), and then a plate fixation model (Model 3) and a pedicle screw fixation model with different screw placement methods and diameters were established (Models 4-15). For all pelvic fracture fixation models, a vertical load of 500 N was applied on the upper surface of the sacrum to test the displacement and stress distribution of the pelvis in the standing state with both legs. The finite element simulation results showed the maximum displacement of Model 1 and Models 3-15 to be less than 1 mm. The overall maximum displacement of Models 4-15 was slightly larger than that of Model 3 (the maximum difference was 177.91×10-3 mm), but the maximum displacement of iliac bone and internal fixation in Models 4-15 was smaller than that of Model 3. The overall maximum stress (maximum stress of the ilium) and maximum stress of internal fixation in Models 4-15 were less than those in Model 3. The maximum displacement difference and maximum stress difference at the fracture of the pubic ramus between each fixed model were less than 0.01 mm and 1 MPa, respectively. The greater the diameter and number of pedicle screws were, the smaller the maximum displacement and stress of the pelvic fracture models were.The maximum displacement and stress of the pelvic fracture models of the screws placed on the injured side of the pubic region were smaller than the screws on the healthy side. Both the anterior and posterior pelvic rings are fixed with a pedicle screw rod system for treatment of Tile C1 pelvic fractures, which can obtain sufficient biomechanical stability and can be used as a suitable alternative to other implants.The greater the diameter and number of pedicle screws were, the greater the pelvic stability was, and the greater was the stability of the screws placed on the injured side of the pubic region than the screws on the healthy side.

Dynamic tensile properties of porcine knee ligament.

The knee plays an essential role in movement. There are four major ligaments in the knee which all have crucial functionalities for human activities. The anterior cruciate ligament (ACL) is the most commonly injured ligament in the knee, especially in athletes. The aim of this study was to investigate the dynamic tensile response of the porcine ACL at strain rates from 800 to 1500 s-1 for simulations of acute injury from sudden impact or collision. Split Hopkinson Tension Bar (SHTB) was utilized to create a dynamic tensile wave on the ACL. Stress-strain curves of strain rates between 800s-1 to 1500s-1 were recorded. The results demonstrated that the elastic modulus of the porcine ACL at higher strain rates was six to eight times higher than that of porcine and human specimens at quasi-static strain rate. However, the failure stress was quite similar while the strain was much smaller than that at the lower strain rate. ACL is highly strain rate sensitive and easier to break with lower failure strain when the strain rates increased to more than 1000s-1. The stress-strain curves indicated that the sketching crimps at the slack region did not happen but switched to the sliding process of collagen fibers and was accompanied by some ruptures, which can develop into tears when strain and stress were large enough. On the other hand, the viscoelastic properties of the ligament, depending on the proteoglycan matrix and the cross-link, showed a limited value in the studied strain rate range.

Primary TKA in patients with major deformities and ligament laxities: promising results of an intermediate constrained implant at mid-term follow-up.

Total knee arthroplasty (TKA) in major deformities with ligament insufficiency may require a higher constraint, with bone sacrifice and concerns about long-term survivorship. Mid-level constraint liners have been recently introduced, but few studies described their outcomes. The aim of this study is to evaluate the short to mid-term outcomes of a constrained postero-stabilized (CPS) insert for primary TKA in moderate to severe deformities. All patients who underwent TKA using a CPS liner in two centers between 2015 and 2017 were included in the study. The indications were: (1) valgus deformity type 2-3 partially correctable; (2) severe varus deformity with varus thrust; (3) post-traumatic deformity with major ligamentous insufficiency and any case of intra-operative ligament insufficiency. Patients were evaluated according to the Knee Society Scoring System (KSS), the Hospital for Special Surgeryscore (HSS), the Western Ontario and Mc Master University (WOMAC) and the Oxford Knee score (OKS). X-rays were evaluated according to the Knee Society Roentgenographic Evaluation System. Forty-seven TKA were included, with an average age of 66.1 ± 10.3years and an average follow-up of 68.4 ± 6months. All patients demonstrated a moderate to severe pre-operative mediolateral instability. All the scores significantly improved (p < 0.0001). In 71.4% of cases, the outcomes were excellent or very good. There were no failures due to aseptic loosening but one failure due to a traumatic ligament rupture. The cumulative survivorship was 97.9% ± 2.1% at 84months. This mid-range constraint total knee replacement demonstrated promising outcomes and survival at mid-term follow-up. IV (case series).

Variations in Strain Distribution at Distal Radius under Different Loading Conditions.

Distal radial fractures exhibit various fracture patterns. By assuming that the strain distribution at the distal radius affects the diversification of the fracture pattern, a parameter study using the finite element model of a wrist developed from computed tomography (CT) images was performed under different loading conditions. The finite element model of the wrist consisted of the radius, ulna, scaphoid, lunate, triquetrum, and major carpal ligaments. The material properties of the bone models were assigned on the basis of the Hounsfield Unit (HU) values of the CT images. An impact load was applied to the scaphoid, lunate, and triquetrum to simulate boundary conditions during fall accidents. This study considered nine different loading conditions that combine three different loading directions and three different load distribution ratios. According to the analysis results, the strain distribution at the distal radius changed with respect to the change in the loading condition. High strain concentration occurred in regions where distal radius fractures are commonly developed. The direction and distribution of the load acting on the radius were considered to be factors that may cause variations in the fracture pattern of distal radius fractures.

Prevalence of Anterior Cruciate Ligament (ACL) Tear Localization Site Role of MRI

Background: The knee is one of the complex joints in the human body and consists of several internal structures that may lead to the emergence of symptoms of knee injuries [1]. The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee that is located in the middle of the knee and runs from the femur (thigh bone) to the tibia (shin bone). It prevents the tibia from sliding out in front of the femur. Together with posterior cruciate ligament (PCL) it provides rotational stability to the knee [2]. In the case of ACL injuries of the knee, magnetic resonance imaging (MRI) is used to diagnose the affected knee. From this point of view, this study aims to identify the sites of ACL tears and evaluate the role of magnetic resonance imaging (MRI) in the diagnosis of Anterior Cruciate Ligament (ACL) tears. Materials and Methods: This study was conducted at the Department of Radiological Diagnostics of Medical Services, Abu Dhabi Police, United Arab Emirates. After getting the institutional approval, the study sample was selected from those with knee injuries. Socio-demographic information about these patients such as gender, age, etc. was recorded. The study sample included 150 patients (113 males and 37 females), their ages ranged between 17 and 52 years, with a mean age of 25 years, and all the patients underwent an initial diagnosis of anterior cruciate ligament injuries. MRI of the knee joint was performed for all cases using different MRI techniques. Results: MRI results confirmed that among the 155 patients, 68% had an ACL tear (89.33% complete tear, 10.67% partial tear), while 32% had no ACL tear. Also, the prevalence of the location of an ACL tear distributed in the femoral end of the knee (62%), the mid third of the knee (14%) and the tibial end (23%). Conclusion: MRI findings have proven to be more effective in assessing complete ACL tear, while the assessment of partial tear requires the use of more developed MRI techniques. All cases of ....

Опыт использования способа открытой лавсанопластики большеберцовой коллатеральной связки

Introduction The tibial collateral ligament (TCL) is one of the major ligaments of the knee and designed to counteract valgus forces. Tibial collateral ligament injury can be treated conservatively with prolonged immobilization and limited weight-bearing on the injured limb. Clinical experience and a high complication rate after conservative treatment indicate the need for surgical intervention to restore the integrity of the TCL. The purpose is to demonstrate a successful management of a patient with ruptured TCL of the right knee joint and substantiate the priority of surgical treatment in the case. Material and methods A clinical case is reported and a brief literature analysis on the topic provided. The experience with open lavsanoplasty used for a patient with rupture of the TCL resulting from dislocated tibia is presented. The effectiveness of treatment was assessed radiologically and physically for the limb functionality and ROM in the knee joint. Results and discussion Open lavsanoplasty performed for the TCL injury resulted in complete restoration of the limb function and anatomical integrity of the ligament. The good result persisted after the removal of the metal construct. The method allowed us to avoid complications being typical for conservative treatment: medial instability of the knee joint and deforming arthritis, and showed the advantages over other surgical treatments used to regain the integrity of the TCL. Conclusion Open lavsanoplasty of the TCL used as the patented technique facilitated complete recovery the injured limb, the functionality, less risk of complications providing a good clinical result.

The use of hyaluronic acid preparations for the treatment of osteoarthritis of the major joints

The authors of the article analyzed the experience of domestic and foreign experts in the effectiveness of the use of HA preparations in the treatment of osteoarthritis of major joints. Background and Objective. To analyze the literature sources in order to determine the effectiveness of the use of HA preparations in the treatment of osteoarthritis of major ligaments. Materials and methods. Articles in specialized scientific journals and collections, Internet resource.Results. The analysis of literature sources determined the important role of HA preparations in the supplying and functioning of the articular cartilage. Researchers are inclined to believe that the ideal HA preparation should be as close as possible to the physiological HA of the synovial fluid of the joint. The developed domestic drug Artro-Patch fully corresponds to these parameters. Conclusions. The use of modern injectable HA preparations is advisable at stages 1–3 of OA. Anti-inflammatory effect of HA preparations makes it possible to reduce the dose and time of administration of non-steroidal anti-inflammatory drugs and, as a consequence, reduce the risk of developing many adverse side effects of NSAIDs. The high level of safety of HA preparations, the absence of serious side effects during their long-term use determine their widespread use in the clinical practice of modern orthopedists.

Effect of 1.5 mm biter-width meniscectomy on cadaveric knee pressure, peak pressure, force, and contact area

This study investigated the immediate biomechanical effects of a biter-width partial medial meniscectomy. Small tears on the free edge of the meniscus are occasionally discovered during arthroscopic knee procedures. Removal of these tears often requires no more width than that of a biter from the edge. While past cadaveric partial meniscectomy studies have reported on the effects of meniscectomies from resection of one-third to three-quarters of meniscal width, the biomechanical sequelae of substantially smaller meniscectomies remain unknown. This study was performed to determine how single-biter-width meniscectomies affect the pressure distribution and peak pressure on the tibial plateau, as these parameters are correlated with increased likelihood of development of osteoarthritis. Eight cadaveric knees were instrumented with a thin-film pressure sensor underneath the menisci while retaining the major ligaments and most of the capsule. Knees were loaded to 1000 N at angles of flexion of 0, 15, 30, and 45 in normal tibio-femoral angles and in 7° of varus. Pressure, peak pressure, force and contact area were recorded. Afterwards, biter-width meniscectomies were performed, and measures repeated. There were significant changes in contact area at most flexion and tibio-femoral angles. There were no changes in the amount of force that was transmitted through the medial compartment. The overall pressure on the tibial plateau did not change in most knee conditions and peak pressure did not change significantly in any condition. The changes in contact area were consistent with our expectations. Similarly, the lack of change in force was also expected. However, the lack of significant changes in pressure and peak pressure represent findings indicating that a biter sized meniscectomy may have clinically insignificant effects on biomechanics.

Use of hyaluronic acid preparations for treatment of osteoarthritis of major ligaments

The authors of the article analyzed the experience of domestic and foreign experts in the effectiveness of the use of HA preparations in the treatment of osteoarthritis of major ligaments.&#x0D; Background and Objective. To analyze the literature sources in order to determine the effectiveness of the use of HA preparations in the treatment of osteoarthritis of major ligaments.&#x0D; Materials and methods. Articles in specialized scientific journals and collections, Internet resource.&#x0D; Results. The analysis of literature sources determined the important role of HA preparations in the supplying and functioning of the articular cartilage. Researchers are inclined to believe that the ideal HA preparation should be as close as possible to the physiological HA of the synovial fluid of the joint. The developed domestic drug Arthro-Patch fully corresponds to these parameters.&#x0D; Conclusions. The use of modern injectable HA preparations is advisable at stages 1–3 of OA. Anti-inflammatory effect of HA preparations makes it possible to reduce the dose and time of administration of non-steroidal anti-inflammatory drugs and, as a consequence, reduce the risk of developing many adverse side effects of NSAIDs. The high level of safety of HA preparations, the absence of serious side effects during their long-term use determine their widespread use in the clinical practice of modern orthopedists.

Design and Development of An Instrumented Knee Joint for Quantifying Ligament Displacements

Abstract Recently, robotic assistive leg exoskeletons have gained popularity because an increased number of people crave for powered devices to run faster and longer or carry heavier loads. However, these powered devices have the potential to impair knee ligaments. This work was aimed to develop an instrumented knee joint via rapid prototyping that measures the displacements of the four major knee ligaments—the anterior cruciate ligament (ACL), posterior crucial ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL)—to quantify the strain experienced by these ligaments. The knee model consists of a femur, lateral and medial menisci, and a tibia-fibula, which were printed from three dimensional (3D) imaging scans. Nonstretchable cords served as main fiber bundles of the ligaments with their desired stiffnesses provided by springs. The displacement of each cord was obtained via a rotary encoder mechanism, and the leg flexion angle was acquired via a closed-loop four-bar linkage of a diamond shape. The displacements were corroborated by published data, demonstrating the profiles of the displacement curves agreed with known results. The paper shows the feasibility of developing a subject-specific knee joint via rapid prototyping that is capable of quantifying the ligament strain via rapid prototyping.

Agreement Between Clinical Examination and Magnetic Resonance Imaging in Acute Knee Trauma With Hemarthrosis.

Hemarthrosis after knee trauma often indicates serious joint injury. Few studies have evaluated agreement between clinical examination and findings from magnetic resonance imaging (MRI). We aimed to describe the agreement between acute clinical examination and subacute MRI findings after acute knee trauma with hemarthrosis and the importance of the subspecialty of the examiner. Longitudinal cohort study. Agreement with MRI findings was evaluated by logistic regression. Helsingborg hospital. Thousand one hundred forty-five consecutive patients with hemarthrosis after knee trauma. Clinical examination and MRI. agreement between clinical examination and findings from MRI. We considered the radiologist's report as the gold standard. Median time (25th, 75th percentile) from injury to clinical examination was 2 (1, 7) days, and from injury to imaging was 8 (5, 15) days. The overall sensitivity and specificity of clinical examination versus MRI for major ligament injury or lateral patella dislocation (LPD) were 70% [95% confidence interval 67-73) and 66% (61-72), respectively. Orthopedic subspecialist knee had the highest agreement with anterior cruciate ligament rupture (adjusted odds ratios were 1.7 (95% confidence interval 1.2-2.3), 1.9 (1.2-3.0) and 5.9 (3.7-9.5) for orthopedic trainees, orthopedic subspecialists other, and orthopedic subspecialist knee, respectively]. For other ligament injuries and LPD, we did not find statistically significant differences. Clinical diagnosis after acute knee injury is relatively unreliable versus MRI findings even when performed by orthopedic specialists. However, the agreement is improved when the examination is performed by an orthopedic knee subspecialist.