Knee joint biomechanics after anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) is an important stabilizer of the knee joint. After ACL rupture, the knee joint has difficulty maintaining its stability; thus the patient often has to receive an ACL-reconstructive surgery to regain the knee joint functions. Unfortunately, traditional transtibial surgical techniques could not fully restore the normal knee joint kinematics during daily activities. Moreover, a higher rate of osteoarthritis was found from the ACL-reconstructed knees compared to the knees without a history of ACL-injuries. The reason for the increased risk of knee osteoarthritis is still unclear, and the pathologies due to abnormal knee joint kinematics remain controversial. The dissertation was to delineate the knee joint motion and loading after ACL-reconstruction. Thirty patients who received ACL-reconstructive surgeries using the traditional transtibial technique and 14 using the recently developed anteromedial portal technique were recruited from the same center (OrthoCarolina). Twenty healthy subjects without history of knee injuries were recruited as the control group. Human motion data and ground reaction force data were collected during level walking and downstairs pivoting using an optical motion capture system. Three-dimensional (3D) knee joint motions were determined from redundant markers using an optimization approach. The 3D knee joint moments and forces were calculated from motion data, ground reaction data by using an inverse dynamics model of the lower extremity. A finite element model was created, and the distributions of stress/strain within articular cartilage under physiological loading were estimated. The results from two groups of patients using different reconstruction techniques were compared. In the transtibial group, excessive internal tibial rotation (2° on average during stance phase), varus rotation and anterior femur translation (swing phase) were observed in the ACL-reconstructed knees when compared to the control group during level walking. The 3D knee joint motion following ACL-reconstruction was found to be influenced by the leg dominance. The motion and load in the uninjured contralateral knee were also affected. During downstairs pivoting, the normal varus rotation and adduction moment were not fully restored by the transtibial technique. Overall, the anteromedial portal technique improved the postsurgical knee joint kinematics by reducing the offsets in the internal tibial rotation, varus rotation and anterior femur translation during level walking. It also improved the adduction moment during downstairs pivoting. At the same time, the anteromedial portal technique may cause a flexion/extension deficit during the stance phase of walking. Results of finite element analysis demonstrated higher pressures within the medial femoral cartilage during the stance phase of walking; it also demonstrated that there is an increased knee joint laxity after ACL-reconstruction. The anteromedial portal technique was overall better than the traditional transtibial technique in respect to postsurgical knee joint compressive loading and contact pressure. The study provides evidence of the possibility by using anatomical single-bundle ACL-reconstruction technique to fight the knee joint osteoarthritis after ligament injury

Lower limb kinematics, kinetics and coordination during a land and cut task; the role of gender and previous ACL injury

Anterior cruciate ligament (ACL) injury continues to be a constant adversary to field sports athletes. Females are widely acknowledged as being at an increased risk of ACL injury, in comparison to males. Athletes who are successful in rehabilitation after surgery and return to their sport are reported to have an increased risk of repeated ACL injury and the development of osteoarthritis. The current thesis utilised a novel, maximal drop-jump land and unanticipated cutting task to assess the lower limb biomechanics of uninjured male and females, and previously ACL injured subjects (ACLr). Discrete measures of lower limb kinematics and kinetics were firstly compared between uninjured males and females, and secondly between the previously injured (PI) leg of ACLr subjects and both the contralateral non-injured (NI) leg and an uninjured subject’s control leg. The results show that females had increased hip internal rotation, the PI leg was not significantly different to the NI leg but was different to the control subject’s leg with increased hip flexion, internal knee abduction moment and transverse plane knee ROM. Lower limb coordination was assessed in the ACLr subjects and both legs of the ACLr subjects had similar coordination patterns. The PI leg however showed different coordination patterns than the control subject’s leg for a number of couplings. Movement and coordination variability were also utilised for a gender and ACLr – control comparison. The female subjects and the PI leg had lower levels of movement and coordination variability than males and the contralateral non-injured leg respectively. The PI leg however, had higher levels of movement and coordination variability than the control subject’s leg. In conclusion, females and previously ACL injured subjects may be at an increased risk of initial ACL injury and the development of osteoarthritis on the PI leg respectively, due to lower levels of movement and coordination variability. Altered biomechanics at the hip were also highlighted as a potential mechanism increasing injury risk in females and ACLr subjects

The Impact of Anterior Cruciate Ligament Reconstructive Surgery on Neuromotor Function

The purpose of this dissertation was to examine the systemic neuromechanical implications in individuals who have had an ACL reconstruction (ACLR) compared to healthy controls. The specific aims addressed were to: 1) examine differences in inter-limb coordination during walking at different speeds, 2) examine differences in trunk, neck and head acceleration during gait, and 3) investigate whether the reaction time responses assessed during stepping are negatively affected by ACLR. The findings of study 1 revealed that maximal coordination stability was achieved when walking at the person’s preferred gait speed. However, individuals with a previous ACLR exhibited reduced coordination stability between the knees, indicative of decreased inter-limb coupling. Further, individuals within the ACLR group who deviated the most from anti-phase coordination during walking also demonstrated lower coordination stability. These findings could contribute to the secondary issues related to ACL damage. Study two examined differences in upper body accelerations during gait, revealing that the ACLR group had a diminished capacity to attenuate gait-related oscillations from the trunk to the head. Further, the vertical acceleration signals for the ACLR individuals were more complex, indicating that they had a reduced ability to optimally accelerations during walking. These results demonstrate the impact of ACL damage is not localized but is more systemic and can negatively impact postural control. The third study assessed how ACLR would impact of general neuromotor function and stepping reaction times. The findings revealed that ACLR individuals had slower reaction times during stepping compared to healthy controls. In contrast to the slowing of reaction time (under postural conditions), there were no changes across any other neuromotor/mechanical measures. This result indicates that the ACLR group had a reduced ability to respond to unexpected stimuli. Overall, the results of this investigation suggest that ACL damage has a wide-spread impact as it not simply localized to the injured knee. The collective results from these studies show changes in movement strategy prioritization in those with an ACLR. These novel findings provide an alternate perspective and may change the ways in which clinicians and healthcare providers assess individuals who have had ACL reconstructive surgery

Joint Coordination Variability In Anterior Cruciate Ligament Reconstructed Subjects During Stair Ambulation Using a Vector Coding Technique

Anterior cruciate ligament (ACL) rupture is a common injury, with an estimated incidence of 120,000 to 200,000 per year in the United States. ACL reconstruction surgery is the standard treatment for this injury to restore knee joint stability and function. While surgical reconstruction has been shown to restore laxity of the knee, current literature lacks consensus on return to normal knee joint kinematics following surgery. Additionally, re-injury is a major risk for those who return to sports activity after reconstruction surgery. Dynamical systems methods for quantifying joint coordination variability have been explored as a method for detecting differences between ACL reconstructed (ACLR) subjects and healthy control subjects. Specifically, altered joint coordination variability has been linked to lower extremity instability, which may indicate re-injury risk. The aim of this study was to assess joint coordination and joint coordination variability using a vector coding technique in ACLR subjects after recovery and return to normal activity. Our hypothesis was that joint coordination variability of ten selected intra-limb knee-knee and knee-hip couplings would be altered in the ACLR group compared to a group of healthy control subjects based on previous findings using similar methods. Thirty subjects (15 ACLR and 15 normal) were analyzed using a motion capture camera system and force plates. Subjects were asked to ascend a staircase in a step-over-step manner at a self-selected pace, turn around on the elevated platform, then descend from the platform down the steps and return to the starting location. We employed a vector coding method using a custom Matlab script to measure coupling angle variability of knee-knee and hip-knee coupled motion during the stair activity. Individuals with ACLR were found to have differences in joint coordination variability (both increased and decreased) in 5 of the 10 joint couplings analyzed as compared with a healthy control group during the stair descent activity. The majority of differences were found to be reductions in variability in the ACLR group as compared with controls. It is believed that there is an optimal amount of variability in any motor system that differentiates between the ability to adapt to environmental instability and the risk for injury. Reduced joint coordination variability indicates avoidance of a particular movement and results in the inability to adapt movement strategies in a dynamic environment. Decreased variability in ACLR subjects has also been linked to re-injury in at least one prospective study. These results combined with previous works provide insight into coordinative function after ACLR and may be useful in improving rehabilitation protocols following surgery as well as identifying those at risk of re-injury

Biomechanical Measures to Assess Recovery from Anterior Cruciate Ligament Injury and Reconstructive Surgery

Anterior cruciate ligament (ACL) injuries are a debilitating injury resulting in abnormal biomechanics. Treatment commonly involves reconstructive surgery, however the tools used to assess the changes in biomechanics due to this procedure may fail to assess movement deficiencies. Therefore, the aim of this thesis was to explore what biomechanical variables are affected by ACL injury and reconstructive surgery and to assess their worth in the monitoring of recovery from ACL injuries and reconstructive surgery. A systematic review of the changes in lower limb biomechanics that occur due to ACL reconstruction identified 51 articles that presented evidence on balance, joint position sense, gait, pivoting, stair ambulation, and landing tasks. Despite trends in certain variables, such as increased knee flexion excursion, there were inconsistencies between articles in presented changes of gait, pivoting, and landing movements. Tasks that related to the proprioceptive function of the limb exhibited consistent improvements due to surgery. This was the first review to provide a synthesis of the evidence around biomechanical changes due to ACL reconstruction and supported the exploration of variables related to the proprioceptive capacity of the injured limb for the use in assessing function. Balance data were collected for eight ACL injured participants before and after surgery, and 45 uninjured participants using collection methods that were integrated into clinical practice. The two samples were similar in age, anthropometrics, and sex. Linear measures of the centre of pressure (CoP) provided a measure of balance performance, and complexity at varying timescales calculated using multiscale sample entropy, an approach that had yet to be explored in ACL injured participants, and complexity index, a summary statistic of the sample entropy at numerous timescales, provided details on the non-linear characteristics of the CoP. Despite previous evidence linking ACL injuries to a reduction in balance performance, the data did not support the use of linear measures. Linear measures had greater variation in uninjured participants than non-linear measures (e.g. coefficient of variation; CoP path length: 16%; mediolateral CoP complexity index: 10%). No trends, supported by a lack of statistical significance, between the involved and comparison limbs were identified (mean±SD pre-surgery CoP path length; ACL involved: 76±19 cm; ACL uninvolved: 87±27 cm; uninjured controls: 93±28 cm). No significant differences were observed due to surgery (mean±SD post-surgery CoP path length; ACL involved: 79±27 cm). Complexity of the CoP, in addition to having a reduced variation in uninjured participants, supported that ACL injury was related to a loss of complexity (mean±SD pre-surgery mediolateral complexity index; ACL involved: 4.9±1.3; uninjured controls: 6.0±0.9) and that reconstructive surgery was able to restore this loss (mean±SD ACL involved mediolateral sample entropy at 6.7 Hz; pre-surgery: 0.9±0.3; 19 weeks post-surgery: 1.2±0.2). The findings provide new evidence to support that ACL injury results in a loss of complexity and that the multiscale sample entropy of the CoP may provide an insight into the changes in lower limb biomechanics that occur due to ACL injury and reconstructive surgery. Comparison of the magnitude of changes in complexity due to ACL reconstructive surgery to uninjured participants, supported that increased complexity may be clinically meaningful. The link between increased complexity and functional outcomes however, is not understood and therefore further research is required to understand this link to establish the usability of complexity as a clinical measure

Biomécanique de l'articulation du genou humain durant la marche - un modèle musculosquelettique hybride

RÉSUMÉ L’articulation du genou est l’une des articulations les plus complexes du corps humain. Elle est exposée à des charges et des mouvements de grandeurs importantes pendant les activités professionnelles, récréatives et même quotidiennes. Cet environnement mécanique exigeant l’expose à diverses contraintes et déformations excessives, des blessures impliquant à la fois les articulations patello-fémorales (PF) et tibio-fémorales (TF). L'arthrose (OA) est l'un des troubles musculo-squelettiques les plus répandus touchant environ 27 millions d'adultes aux États-Unis seulement. La rupture du ligament croisé antérieur (LCA) est également une lésion articulaire commune avec une prévalence beaucoup plus élevée chez les sujets féminins que chez les sujets masculins. Une bonne connaissance de la biomécanique fonctionnelle de l’articulation du genou et des facteurs qui l'affectent, dans des conditions saines et pathologiques, est une condition préalable pour élaborer des stratégies efficaces pour la prévention et le traitement de ces blessures. Les modèles musculo-squelettiques (MS) de l'extrémité inférieure promettent d'améliorer notre compréhension de la fonction articulaire du genou, de ses blessures et aussi des programmes de prévention et des traitements associés. Plusieurs modèles analytiques et d'éléments finis (EF) avec différents degrés de précision et de raffinement ont été développés. Ils se sont présentés comme une alternative fiable aux méthodes expérimentales qui ont des limitations majeures, principalement liées à leurs coûts élevés, aux difficultés liées aux précisions des mesures et à la reproduction parfois impossible de certaines situations physiologiques. Cependant, de nombreuses hypothèses sont souvent formulées dans certains modèles MS (lors de l'estimation des forces musculaires et des forces de contacts articulaires). Le genou est généralement idéalisé comme une articulation 2D avec son mouvement contraint dans le plan sagittal, négligeant ainsi les déplacements et les équations d'équilibre dans les plans restants. Avec les forces musculaires estimées, l'équilibre statique dans le plan frontal est donc considéré pour estimer les forces du plateau tibial négligeant la résistance passive du genou, la géométrie articulaire, et en supposant des centres de contact médial/latéral fixes. Pour évaluer les effets de telles hypothèses, un modèle MS hybride de l'extrémité inférieure incluant un modèle élément finis (EF) du genou 3D a été utilisé pour simuler la phase d’appui de la marche.----------ABSTRACT Human knee joints experience loads and movements of substantial magnitudes during occupational, recreational and even regular daily living activities. This demanding mechanical environment exposes them to a host of painful and debilitating deformities, injuries and degenerations involving both patellofemoral (PF) and tibiofemoral (TF) articulations. Osteoarthritis (OA) is one of the most prevalent musculoskeletal (MS) disorders affecting approximately 27 million adults in the US alone. ACL rupture is, also, a common joint injury with much higher prevalence reported in female athletes compared to their male counterparts. Effective preventive measures and treatment managements of such disorders require a sound knowledge of the joint behavior in both healthy and pathologic conditions. MS modeling of the lower extremity is promising to improve the current understanding of the knee joint function and injuries and consequently associated prevention and treatment programs. Several analytical and finite element (FE) models with different degrees of precision and refinement have been developed. They are considered as a reliable alternative to experimental methods that have major limitations, mainly related to their high costs, difficulties related to measurement accuracy and reproduction of some physiological situations. However, numerous assumptions are often made in some MS models (when estimating muscle forces and joint contact loads). The knee is commonly idealized as a planar (2D) joint with its motion constrained to remain in the sagittal plane, neglecting thus both displacements and equilibrium equations in remaining planes. With muscle forces predicted, the static equilibrium in the frontal plane is consequently considered to estimate tibial compartmental loads neglecting the knee joint passive resistance, the knee geometry, and assuming medial/lateral contact centers. To evaluate the effects of such assumptions, a hybrid MS model of the lower extremity incorporating a detailed validated 3D knee FE model was used to simulate the stance phase of gait. This model of the knee joint is made of bony structures (tibia, femur and patella) and their compliant cartilage layers as well as menisci, major TF (anterior cruciate ligament, ACL; posterior cruciate ligament, PCL; lateral collateral ligament, LCL; medial collateral ligament, MCL) and PF (medial PF ligament, MPFL; lateral PF ligament, LPFL) ligaments, patellar tendon (PT), and lower extremity muscles (e.g., quadriceps, hamstrings and gastrocnemius)

Analyse biomécanique de l'articulation de genou durant la bipédie humaine

RÉSUMÉ Les activités de la vie quotidienne comme la marche et la montée d'escaliers imposent des charges et des mouvements relativement importants sur l'articulation du genou humain. Cette charge mécanique augmente dans de nombreuses tâches professionnelles et récréatives entraînant des blessures et des dégénérescences dans les ligaments, les ménisques, le cartilage et l’os. Toute faiblesse ou modification par rapport à la structure native qui conduit à la dégénérescence dans l'un de ces composants influencent la réponse de l'ensemble du joint et augmente le risque d'autres perturbations. Les gestions efficaces, non-opératoires et post-opératoires des désordres affectant le joint du genou humain exigent une bonne connaissance des distributions des contraintes et des déformations dans les différentes composantes constituant le joint, dans les situations intacte et altérée. Ces valeurs, à leur tour, dépendent fortement non seulement des charges extérieures et des forces d’inertie, mais aussi des activités musculaires à travers le joint. De ce fait la précision dans l'estimation des forces musculaires a une incidence directe sur la fiabilité des contraintes et des déformations prédites dans le joint. Les mesures directes in vivo des contraintes tissulaires et des forces musculaires restent invasives. Par contre la modélisation numérique est reconnue comme un outil complémentaire indispensable pour estimer plusieurs variables d’intérêt. Ainsi, les difficultés techniques rencontrées dans les mesures de mouvements et la considération plus réaliste des charges physiologiques rendent les tests in vitro également limités surtout quand on regarde des variables internes comme les contraintes et les déformations dans les ligaments et le cartilage. Pour atteindre ces objectifs, un modèle éléments finis itératif, contrôlé par les données cinématique et cinétique collectées durant la marche humaine, qui tient compte des structures passives du joint du genou et l’ensemble de la musculature active de l'extrémité inférieure a été utilisé. Dans ce modèle les articulations de la hanche et de la cheville ont été considérées comme des joints rigides simplement sphériques (3D pour la hanche et 2D pour la cheville), alors que l’articulation de genou est représentée sous la forme d'un modèle déformable d’éléments finis non linéaire. Les cartilages et les ménisques constituant le joint ont été modélisés comme des structures composites formées d’une matrice hyper-élastique renforcée par des réseaux non-homogènes de fibre de collagène avec des propriétés mécanique non linéaires.----------ABSTRACT Activities of daily living such as walking and stair climbing impose relatively large loads and movements on the human knee joint. This mechanical burden increases in many occupational and recreational tasks causing injuries and degenerations in joint ligaments, menisci, cartilage and bone. Any failure, degeneration or alteration in one of these components influences the response of the entire joint and likely increases the risk of further perturbations. Effective preventive and conservative/surgical managements of joint disorders depend hence on a sound knowledge of stress and strain distributions in various components under both intact and altered conditions. These values, in turn, are heavily dependent not only on external loads and inertial forces but on muscle activities across the joint. As such, accuracy in estimation of muscle forces has a direct bearing on the reliability of stresses and strains. Since direct in vivo measurements of tissue stresses and muscle forces remain invasive, computational modeling is recognized as a vital complementary tool to estimate multiple variables of interest. Due to technical difficulties in measurements and consideration of physiological loads and motions, in vitro testing is also limited especially when looking for cartilage/meniscus stresses/strains and ligament forces. Towards these objectives, an iterative kinematics-driven FE model that accounts for the passive structures of the knee joint and active musculature of the lower extremity is employed. This model incorporates the hip as 3D and the ankle as 2D spherical joints whereas the knee is represented as a complex FE model with nonlinear depth-dependent fibril-reinforced cartilage and menisci, ligaments with distinct nonlinear properties and initial strains, patellofemoral and tibiofemoral joints. Based on reported in vivo measurements, hip/knee/ankle joint rotations/moments and ground reaction forces at foot during the gait stance phase collected in asymptomatic subjects and subjects with severe knee OA are used to separately model both groups. Analyses are performed at 6 time instances corresponding to beginning 0% (heel strike), 5%, 25%, 50%, 75% and 100% (toe off) of the stance phase. At each stance period, muscle forces at the hip, knee and ankle are predicted using static optimization (sum of cubed muscle stresses) with moment equations as constraints (3 at knee, 3 at hip, and 1 at ankle). The Knee joint response is subsequently analyzed with updated muscle forces as external loads and iterations at deformed configurations continue till convergence is reached

Viscoelastic properties of soft tissues:application to knee ligaments and tendons

Ligaments play a central role in the stability of the knee. Due to the increase in sport activities of the young population, rupture of the anterior cruciate ligament (ACL) has become a frequent clinical problem. A surgical procedure replacing the deficient ligament is performed to restore the knee's initial stability. Although this surgical technique is widespread and well established, long term clinical results are inconsistent and the stability of the knee is not always restored, leading to premature arthrosis of the knee. This inconsistency of ACL replacement motivated the present study. "Optimal" ACL replacement only can be performed if the static and dynamic properties of the ligament are precisely known. In order to investigate these mechanical properties, an experimental set-up was developed to test human cruciate ligaments, as well as patellar tendon, which is commonly used for cruciate ligament replacement. Traction tests at different constant rates of elongation and stress relaxation tests were performed at controlled temperature (37°C) and humidity (100%). Results showed that cruciate ligaments and patellar tendons exhibit a non-linear elastic behavior in addition to a viscous behavior. The viscous behavior encompassed two phenomena: first a behavior where stress depended on strain rate (short term memory effects) and second a behavior where stress relaxed on a longer time scale (long term memory effects). In order to describe the different mechanical behaviors of the specimens in a general mechanical framework, a theoretical model was developed by simultaneously taking into account the non-linear elastic behavior, the short term memory effects and the long term memory effects. This proceeding satisfied the basic mechanical and thermodynamical requirements. The originality of the present model is based on the fact that the different mechanical behaviors are described in one framework allowing a compact description of the biomechanical properties of different soft tissues. The description of the short term memory effects is new in situations involving large deformations. The model is restricted by considering the specimens as isotropic, homogeneous and incompressible. The identification process of the different mechanical behaviors was facilitated with the proposed model. The non-linear elasticity was described with two parameters, the short term memory effects with one parameter and the long term memory effects with six parameters. No statistical differences were found between the parameters used for the anterior cruciate ligaments, the posterior cruciate ligaments and patellar tendons. The non-linear elastic behavior was implemented in a finite element code. The stress field in an ACL was calculated during a knee flexion and a tibial drawer test. The calculated stress field was inhomogeneous, with the highest stress in the anteriormedial part of the ACL. It was found that internal rotation of the knee generally increased the calculated stress in the ACL. These numerical results agree with in vitro studies given in the literature. The numerical results yielded a stress field in the ligament which was complementary to in vitro studies, where only the resultant ligament force can be measured. Several useful clinical conclusions can be drawn from the present biomechanical study. Diagnosis of an ACL rupture is generally performed by a contralateral comparison of antero-postero knee laxity (tibial drawer test) using a quasi-static load. However, diagnosis of an injured knee would be more accurate if the antero-postero load was dynamically applied to the knee: in this case, a knee with a rupture ACL would not show any effect, whereas a knee with an intact ACL would become stiffer with increasing the strain rate. In case of ACL replacement, the graft should be preconditioned in order to diminish the effects of stress relaxation. During the rehabilitation program after an ACL suture or replacement, flexion of the knee in an internal position should be omitted because internal rotation increases the stresses in the ligament

Dynamics, Electromyography and Vibroarthrography as Non-Invasive Diagnostic Tools: Investigation of the Patellofemoral Joint

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, but expensive, time consuming and can be used only under static conditions. Moreover, due to limited resolution the radiographic techniques cannot reveal early stage arthritis. The arthroscopy is often the only reliable option, however due to its semi-invasive nature, it cannot be considered as a practical diagnostic tool. Therefore, the motivation for this work was to combine three scientific methods to provide a comprehensive, non-invasive evaluation tool bringing insight into the in vivo, dynamic conditions of the knee joint and articular cartilage degeneration. Electromyography and inverse dynamics were employed to independently determine the forces present in several muscles spanning the knee joint. Though both methods have certain limitations, the current work demonstrates how the use of these two methods concurrently enhances the biomechanical analysis of the knee joint conditions, especially the performance of the extensor mechanism. The kinetic analysis was performed for 12 TKA, 4 healthy individuals in advanced age and 4 young subjects. Several differences in the knee biomechanics were found between the three groups, identifying age-related and post-operative decrease in the extensor mechanism efficiency, explaining the increased effort of performing everyday activities experienced by the elderly and TKA subjects. The concept of using accelerometers to assess the cartilage degeneration has been proven based on a group of 23 subjects with non-symptomatic knees and 52 patients suffering from knee arthritis. Very high success (96.2%) of pattern classification obtained in this work clearly demonstrates that vibroarthrography is a promising, non-invasive and low-cost technique offering screening capabilities