Ligament Insertion Research Articles

Artrosis de rodilla asociada a deformidad extraarticular tratada mediante prótesis total de rodilla y osteotomía correctora de forma simultánea

Background and objectiveCorrect mechanical limb alignment is crucial in Total Knee Arthroplasty (TKA) and is particularly difficult to achieve when the knee osteoarthritis (KOA) is associated with an Extra-Articular Deformity (EAD). Our objective is to present a surgical option in cases of severe knee arthritis associated with an EAD (indications, mechanical planning and surgical technique), pros and cons and discuss the results with this one-stage technique. Material and methodsWe retrospectively reviewed all cases of severe KOA associated with EAD treated surgically in our institution from 2010-2016. In our study, we only included cases treated via simultaneous TKA and corrective osteotomy (CO) and with a minimum follow-up period of three years. In terms of imaging, we determined the apex and angulation of the EAD as well as the modification of the mechanical parameters post-treatment. The pre- and postoperative clinical assessment was performed using the Knee Society Score (KSS). ResultsTen patients (10 knees) underwent combined surgery (simultaneous TKA and CO). The mean age was 67.7 years and the mean follow-up period was 49.2 months. The mechanical parameters were consistently corrected in the post-operative period. The mechanical axis deviation (MAD) shifted from a mean value of 6.9cm to 0.45cm and the joint line was rendered horizontal in all cases. In none of the cases did the bone resection affect the insertion of the colateral ligaments. The mean KSS value improved from 32.3 points preoperatively to 79.4 postoperatively. There were no major complications, but there were two planning errors that did not impact upon the end result. ConclusionsIn severe associated KOA and EAD, the combined surgical treatment proposed achieves in one stage an effective anatomical and mechanical correction which is crucial to optimise clinical results and implant durability. The surgery is complex and requires careful planning.

Enthesitis in IBD Patients.

Inflammatory bowel disease (IBD) is marked by chronic inflammation of the gastrointestinal tract and encompasses two major subtypes, Crohn's disease (CD) and ulcerative colitis (UC). IBD is frequently accompanied by extraintestinal manifestations (EIMs), with axial and peripheral spondyloarthritis (SpA) being the most common. Enthesitis, an inflammation of the bone insertions of capsules, ligaments, and tendons, represents an initial lesion in SpA. However, enthesitis remains an underestimated and often obscured EIM. The early detection of subclinical entheseal involvement in IBD patients using ultrasound (US) could provide an opportunity for timely intervention. US is a more feasible and affordable approach than magnetic resonance imaging (MRI). While previous meta-analyses have reported on the incidence and prevalence of SpA in IBD, specific attention to enthesitis has been lacking. Therefore, this narrative review aims to assess the current knowledge on existing IBD-SpA cohorts, focusing specifically on enthesitis.

Ex vivo evaluation of the soft tissue components of the equine stifle using 3 Tesla magnetic resonance imaging under flexion, extension, and loading.

High-field MRI of the equine stifle provides high-resolution information about soft tissues that is useful in the diagnosis of stifle lameness. The aim of this prospective anatomic study was to describe the appearance, position, size, and shape of the equine femorotibial ligaments, meniscal ligaments, and menisci using 3 Tesla MRI under extended, extended-loaded, and flexed conditions. Additionally, histologic examination of the collateral and cruciate ligaments (CLs) of a single stifle was performed to compare with MRI images. In extension, mild variations in MRI signal intensity were apparent in the CLs, and the cranial had two distinct longitudinal regions indicating two ligament bundles. Flexion had minor effects on CL signal intensity and altered the tibial angles of attachment. Histology indicated that both CLs were comprised of two fiber bundles. The collateral ligaments were the same low-signal intensity. The medial collateral ligament had a smaller cross-sectional area than the lateral, and flexion increased the length of the medial collateral ligament and the cross-sectional area of the lateral. Low loads in extension did not affect the MRI appearance of stifle soft tissues. Flexion of the stifle impacted cruciate ligament insertion angles and the size and shape of collateral ligaments. This study provides support for the use of MRI to understand the anatomy and function of stifle ligaments.

The multidirectional roles of the anterior oblique ligament and dorsoradial ligament of the thumb carpometacarpal joint.

The multidirectional biomechanics of the thumb carpometacarpal (CMC) joint underlie the remarkable power and precision of the thumb. Because of the unconfined nature of thumb CMC articulation, these biomechanics are largely dictated by ligaments, notably the anterior oblique ligament (AOL) and the dorsoradial ligament (DRL). However, the rotational and translational stabilizing roles of these ligaments remain unclear, as evidenced by the variety of interventions employed to treat altered pathological CMC biomechanics. The purpose of this study was to determine the effects of sectioning the AOL (n = 8) or DRL (n = 8) on thumb CMC joint biomechanics (rotational range-of-motion [ROM] and stiffness, translational ROM) in 26 rotational directions, including internal and external rotation, and in eight translational directions. Using a robotic musculoskeletal simulation system, the first metacarpal of each specimen (n = 16) was rotated and translated with respect to the trapezium to determine biomechanics before and after ligament sectioning. We observed the greatest increase in rotational ROM and decrease in rotational stiffness in flexion directions and internal rotation following DRL transection and in extension directions following AOL transection. The greatest increase in translational ROM was in dorsal and radial directions following DRL transection and in volar directions following AOL transection. These data suggest the AOL and DRL play complementary stabilizing roles, primarily restraining translations in the direction of and rotations away from the ligament insertion sites. These findings may inform future interventions or implant designs for pathological CMC joints.

Stabilizing effect of total ankle arthroplasty by distal translation and lateralization of talus in varus ankle deformity.

In end-stage arthritis indicated for total ankle arthroplasty (TAA), full-thickness cartilage damage, subchondral bone defect/shaving, and fluttering of the talar dome occur, shortening the distance between the tibial and talar insertions of ligaments and leading to laxity of ligaments surrounding the ankle joint. Under such conditions, medial ligaments (including the deltoid ligament) would not be expected to function properly. To stabilize the ankle joint during the stance phase, medial ligament function under tension is important. This study therefore examined whether TAA contributes to lengthening of the medial tibio-talar joint as evaluated radiographically, as a preferable method for achieving tensile effects on medial ligaments. Twenty-four feet with end-stage varus deformity of the ankle joint that underwent TAA were retrospectively investigated, excluding cases with any malleolar osteotomy or fracture. Distance between proximal and distal insertions of medial ligaments, lateralization of the talus, and talar tilt angle under valgus/varus stress condition were evaluated pre- and postoperatively. Distance between proximal and distal insertions of medial ligaments was significantly elongated after TAA. At the same time, the talus showed significant lateralization. Furthermore, talar tilt under valgus/varus stress conditions was also significantly reduced after TAA. TAA affects distal translation and lateralization of the talus in cases of varus ankle deformity. These effects might contribute to re-providing tensile force on lax medial ligaments, improving ligament function.

Compositional, Structural, and Biomechanical Properties of Three Different Soft Tissue-Hard Tissue Insertions: A Comparative Review.

Connective tissue attaches to bone across an insertion with spatial gradients in components, microstructure, and biomechanics. Due to regional stress concentrations between two mechanically dissimilar materials, the insertion is vulnerable to mechanical damage during joint movements and difficult to repair completely, which remains a significant clinical challenge. Despite interface stress concentrations, the native insertion physiologically functions as the effective load-transfer device between soft tissue and bone. This review summarizes tendon, ligament, and meniscus insertions cross-sectionally, which is novel in this field. Herein, the similarities and differences between the three kinds of insertions in terms of components, microstructure, and biomechanics are compared in great detail. This review begins with describing the basic components existing in the four zones (original soft tissue, uncalcified fibrocartilage, calcified fibrocartilage, and bone) of each kind of insertion, respectively. It then discusses the microstructure constructed from collagen, glycosaminoglycans (GAGs), minerals and others, which provides key support for the biomechanical properties and affects its physiological functions. Finally, the review continues by describing variations in mechanical properties at the millimeter, micrometer, and nanometer scale, which minimize stress concentrations and control stretch at the insertion. In summary, investigating the contrasts between the three has enlightening significance for future directions of repair strategies of insertion diseases and for bioinspired approaches to effective soft-hard interfaces and other tough and robust materials in medicine and engineering.

Snapping Biceps Femoris Repair: A Rare Cause of Lateral Knee Pain

Background: Snapping biceps femoris syndrome (SFS) represents a rare clinical entity in which the biceps femoris subluxates over the fibular head in deep flexion. Two primary pathophysiologies have been described including a prominent or abnormal fibular head morphology. Others have implicated an anomalous biceps femoris insertion. The diagnosis is made clinically, with operative and nonoperative intervention strategies available for treatment. Indications: SFS often results in audible snapping and associated pain at the lateral fibular head. When recalcitrant to nonoperative management, surgical intervention can lead to resolution of symptoms. We present the case of a college-aged male who has bilateral symptoms, worse on the right, which have resulted in significant activity modification and daily discomfort recalcitrant to anti-inflammatory medication and physical therapy. Technique Description: The patient was placed supine on the operating room table with an ipsilateral bump under the hip to assist in exposure of the lateral aspect of the knee. Examination under anesthesia (EUA) confirmed the snapping biceps femoris. A lateral approach to the knee and a common peroneal neurolysis was performed. The biceps femoris insertional anatomy was examined for anomalous tendon insertion or insertional tearing. The prominent fibular head was exposed and resected, with careful attention not to disrupt the lateral collateral ligament or popliteofibular ligament insertion sites. The biceps femoris was then repaired to the prepared bony bed of the fibula with one double-loaded suture anchor. Repeat EUA confirmed complete resolution of snapping even with maximal internal rotation of the tibia; this was carefully examined again with the tourniquet deflated to ensure its compressive effect was not partially responsible for the resolution. Results: Published data pertaining to SFS is limited to case reports and small case series. With appropriate indications, surgical intervention yields promising results with a high percentage of patients returning to prior level of activity or prior participation level in sport. Discussion/Conclusion: SFS can be diagnosed with a careful clinical assessment. When recalcitrant to nonoperative management, it is effectively treated with surgical intervention to restore normal fibular anatomy, and prevent recurrent instability and persistent pain. The presented technique allows for appropriate management of these rare injuries. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Computational study of extrinsic factors affecting ACL strain during single-leg jump landing

BackgroundNon-contact anterior cruciate ligament (ACL) injuries are a major concern in sport-related activities due to dynamic knee movements. There is a paucity of finite element (FE) studies that have accurately replicated the knee geometry, kinematics, and muscle forces during dynamic activities. The objective of this study was to develop and validate a knee FE model and use it to quantify the relationships between sagittal plane knee kinematics, kinetics and the resulting ACL strain.Methods3D images of a cadaver knee specimen were segmented (bones, cartilage, and meniscus) and meshed to develop the FE model. Knee ligament insertion sites were defined in the FE model via experimental digitization of the specimen’s ligaments. The response of the model was validated against multiple physiological knee movements using published experimental data. Single-leg jump landing motions were then simulated on the validated model with muscle forces and kinematic inputs derived from motion capture and rigid body modelling of ten participants.ResultsThe maximum ACL strain measured with the model during jump landing was 3.5 ± 2.2%, comparable to published experimental results. Bivariate analysis showed no significant correlation between body weight, ground reaction force and sagittal plane parameters (such as joint flexion angles, joint moments, muscle forces, and joint velocity) and ACL strain. Multivariate regression analysis showed increasing trunk, hip and ankle flexion angles decreases ACL strain (R2 = 90.04%, p < 0.05).ConclusionsSoft landing decreases ACL strain and the relationship could be presented through an empirical equation. The model and the empirical relation developed in this study could be used to better predict ACL injury risk and prevention strategies during dynamic activities.

Impact of Structural Compliance of a Six Degree of Freedom Joint Simulator on Virtual Ligament Force Calculation in Total Knee Endoprosthesis Testing.

The AMTI VIVO™ six degree of freedom joint simulator allows reproducible preclinical testing of joint endoprostheses under specific kinematic and loading conditions. When testing total knee endoprosthesis, the articulating femoral and tibial components are each mounted on an actuator with two and four degrees of freedom, respectively. To approximate realistic physiological conditions with respect to soft tissues, the joint simulator features an integrated virtual ligament model that calculates the restoring forces of the ligament apparatus to be applied by the actuators. During joint motion, the locations of the ligament insertion points are calculated depending on both actuators' coordinates. In the present study, we demonstrate that unintended elastic deformations of the actuators due to the specifically high contact forces in the artificial knee joint have a considerable impact on the calculated ligament forces. This study aims to investigate the effect of this structural compliance on experimental results. While the built-in algorithm for calculating the ligament forces cannot be altered by the user, a reduction of the ligament force deviations due to the elastic deformations could be achieved by preloading the articulating implant components in the reference configuration. As a proof of concept, a knee flexion motion with varying ligament conditions was simulated on the VIVO simulator and compared to data derived from a musculoskeletal multibody model of a total knee endoprosthesis.

A Recess Is Observed Between the Posterior Knee Capsule and the Meniscotibial Ligament Complex in Pediatric Specimens

To define the surgical anatomy of the meniscotibial ligament complex of the pediatric medial and lateral menisci and their relation to the proximal tibial physis and posterior joint capsule. Fourteen pediatric cadaveric knee specimens (aged 3 months to 11 years) were dissected to clarify the relation of the posterior knee capsule, the meniscus, and the meniscotibial ligament complex. Metallic markers were placed marking the meniscotibial ligament capsular attachment on the proximal tibia. Specimens underwent computed tomography scanning to evaluate pin placement and relation to the physis. A digital measurement tool was used to measure the distances between the proximal tibial physis and the pins (placed at 5 points on both the lateral and medial menisci). In each specimen, clear separation was noted between the posterior joint capsule from the meniscus and meniscotibial ligament complex in the medial and lateral compartments. There was an increase in the distance between the proximal tibial physis and the insertion points of the meniscotibial ligament complex with increasing specimen age. For both the medical and lateral menisci in group 1, the median meniscotibial ligament insertion points were often less than 7 mm (interquartile range, 0.00-7.8 mm) away from the physis. The median meniscotibial ligament insertion points in group 2 tended to be farther from the physis but always less than 20 mm (interquartile range, 2.5-17.5 mm)-and as close as less than 5 mm (lateral posterior root). In this anatomic study of pediatric knees, we observed a distinct recess/cul-de-sac space between the posterior knee capsule and meniscal attachments in all specimens. This defines a distinct plane between the posterior knee capsule and the meniscotibial ligament complex, with a distance between the physis and meniscotibial ligament capsular attachments that increases with age. The anatomic parameters evaluated in our study should be considered as future meniscal repair and transplantation techniques aim to restore the meniscal anatomy, stability, and mobility provided by the meniscotibial ligament complex and capsule structures.

Subtuberosity anterior closing wedge osteotomy to correct the increased posterior slope of the tibial plateau

Reduction of increased reclination of the tibial plateau (posterior slope) to improve the anterior stability of the knee joint. Increased posterior reclination of the tibial plateau greater than 12° in combination with recurrent instability after anterior cruciate ligament (ACL) reconstruction. Hyperextension of more than 15° (relative). Anterior skin incision approximately 8-10 cm above the tibial tuberosity. Insertion of two converging guidewires directly below the patellar tendon ending obliquely in the area of the posterior cruciate ligament (PCL) insertion. Control of the wire position with the image intensifier core. Oscillating saw osteotomy. Removal of the wedge and closure of the osteotomy. Osteosynthesis with interfragmentary screw and medial angle-stable plate. Partial load with 10-20 kg for 2 weeks, then step by step increase in load. Mobility: free. To date we have operated on 36patients with recurrent instability after ACL reconstruction (20men, 16women, average age 34.4 years) in the manner described in this article. In 25cases, enlarged bone tunnels were filled with allogeneic bone at the same time. The posterior slope of the tibial plateau could be reduced from an average of 14.5° to8.8°. In 28cases another ACL reconstruction was performed after an interval of 4-12months. The Lysholm score significantly increased from 76.3 points to 89.2 points.

Detection of subclinical enthesitis by ultrasonography in patients with psoriasis and controls.

Psoriasis is a widespread chronic inflammatory skin disease; enthesitis is inflammation of the tendon, ligament, and joint capsule insertion, prevalent in patients with psoriatic arthritis. The aim of study to evaluate the utility of the Madrid Sonography Enthesitis Index scoring system for accurate detection of subclinical enthesitis in patients with Psoriasis compared with healthy controls. Another objective was to assess increase in enthesis area and Psoriatic arthritis incidence, in a prospective 1-year follow-up. Patients aged ≥18 years who were diagnosed with Psoriasis, without musculoskeletal complaints, and who did not have any clinical sign and/or symptom of enthesitis and synovitis were included in the study. The patients and healthy controls were evaluated with ultrasonography. Ultrasonography evaluation consisted of the detection of gray-scale enthesitis and power Doppler signal in the enthesis areas. The Madrid Sonography Enthesitis Index scoring system was used to quantify the extent of the sonographic enthesis abnormalities. The mean MASEI score, structure, thickness, erosion, and calcification were significantly higher in the Psoriasis group than in the control group. The mean MASEI score, structure, erosion, and calcification measurements were significantly higher at the last examination when compared to the first examination. The triceps was the most commonly affected tendon in both groups. Ultrasonography is an important tool for diagnosis and follow-up of subclinical enthesitis in patients with psoriasis. Regardless of disease duration and severity, patients should be screened using ultrasonography at yearly intervals.

Regulatory mechanisms and regeneration strategies of the soft–hard tissue interface in the human periodontium

AbstractThe soft‐hard tissue interface of the human periodontium is responsible for periodontal homeostasis and is essential for normal oral activities. This soft‐hard tissue interface is formed by the direct insertion of fibrous ligaments into the bone tissue. It differs from the unique four‐layer structure of the fibrocartilage interface. This interface is formed by a combination of physical, chemical, and biological factors. The physiological functions of this interface are regulated by different signaling pathways. The unique structure of this soft‐hard tissue interface has inspired scientists to construct biomimetic gradient structures. These biomimetic systems include nanofiber scaffolds, cell sheets, and hydrogels. Exploring methods to repair this soft‐hard tissue interface can help solve clinically unresolved problems. The present review examines the structure of the soft‐hard tissue interface of the periodontium and the factors that influence the development of this interface. Relevant regulatory pathways and biomimetic reconstruction methods are also presented to provide ideas for future research on interfacial tissue engineering.

Topographic and Structural Anatomy of the Suspensory Ligament of the Penis: Implications for Phalloplasty.

The suspensory ligamentous system of the penis supports the penis when erect and plays a key role during coitus. These ligaments, which are prone to injury during coitus, are clinically important in penile reconstruction procedures. The current study investigated the macro- and microanatomy of the suspensory ligamentous system of the penis to determine the origin, course, insertion, dimensions, and tissue composition of these ligaments, knowledge of which is vital for successful penile reconstruction procedures. The study utilized a total of 49 cadavers. Gross anatomy dissection, MRI, and histological staining were performed to elucidate the topography, dimensions, and tissue composition of the suspensory ligaments of the penis. Three ligaments were observed to form the suspensory ligamentous system of the penis. The most superficial is the fundiform ligament, which consists of superficial bundles and deep median bundles, with the former arising from the Scarpa's fascia and the latter arising from the linea alba of the anterior abdominal wall; both inserted into the superficial fascia of the penis. The suspensory ligament of the penis arose from the pubic symphysis and inserted into the deep fascia (Buck's fascia) of the penis. The arcuate ligament arose from the body of the pubis and pubic symphysis and inserted into the Buck's fascia. The ligaments were determined to consist of adipose tissue, collagen fibers, elastic fibers and reticular fibers, in varying proportions. The suspensory ligaments of the penis exhibit a fan-like structure on the penis that allows the forward movement of the penis as a result of engorgement of the erectile bodies while simultaneously offering support.

TVS-guided cervical strain elastography is more effective than measuring cervical length as an independent predictor of spontaneous preterm delivery in asymptomatic, high-risk women during the mid-trimester

Introduction TVS (Transvaginal Sonography) guided Cervical strain elastography (CSE) is now available in tertiary referral centers of LMICs (Low- and Middle-Income Countries). TVS cervical length (CL) assessment is being used routinely. Still, elastography is not used in clinical settings, although enough evidence suggests good predictive value towards sPTD (spontaneous Preterm Delivery). The clinical utility of elastography has not been tested among high-risk populations of LMICs for the prediction of sPTD. Aim To test the performance of TVS-CSE in predicting sPTD among asymptomatic women in the mid-trimester at risk of sPTD either due to clinical factors or due to a short cervix. Method Prospective observational study performed at a tertiary hospital in South India. Asymptomatic pregnant women between 16 and 24 weeks who had one or more clinical risk factors for sPTD or CL <2.5 cm were included. GE Voluson E-8 ultrasound machine was used. After CL measurement, elastography color coding was noted around the internal-os in the sagittal view. The strain ratio (SR) was calculated using the trace method on three ROIs (Region of Interest): Internal-os in sagittal view (IN), whole cervix in sagittal view (WN), and internal-os in axial view (AN). Reference Tissue (RT) of similar size and depth was chosen in the darkest blue region on elastography (stiffest area) outside the cervix, posterior/lateral to the cervix over the ligament insertion. Lower the SR – softer the cervix. Two trained fetal medicine consultants performed the initial 57 cases until intra/inter-observer correlation was satisfactory. Delivery before 37 weeks (after 26 weeks), in which the process of labor has begun spontaneously, or labor was induced after PPROM—was considered as sPTD. SRs were assessed to determine how well they could predict sPTD independently or combined with cervical length. Results Out of 221 recruited,17 were lost to follow-up after 32 weeks; 204 were delivered in our hospital. Irrespective of the route of delivery, 71 (34.8%) had sPTD. Of the remaining 133, 106 delivered at term, and 27 underwent medically indicated PTD. Apart from multiple pregnancies, no other preterm-related risk factors (including CL < 2.5 cm) showed significant association with sPTD. Red CSE pattern around internal-os was associated with a significantly higher (54.5%) incidence of sPTD. CLs were similar (3.63 ± 0.67 vs. 3.63 ± 0.80, p = .981) whereas SRs in all three ROIs were significantly lower among sPTD group versus no sPTD group (IN:0.65 ± 0.29 vs 0.79 ± 0.30 p = .001, WN:0.34 ± 0.13 vs 0.39 ± 0.15, p = .013, AN:0.37 ± 0.16 vs 0.48 ± 0.26, p = .002, respectively). Using ROC curves, while CL was not predictive (AUROC 0.49, p = .81), SRs showed moderate predictive value toward sPTD with the best AUC of 0.624 (p = .003) at IN. Prediction was slightly better for early sPTD <32 weeks (AUC 0.653 p = 0.03). The best cutoff for SR at IN was 0.72, below which there was a moderate accuracy in predicting sPTD (sensitivity 52.11%, specificity 60.9%, PPV 41.57%, NPV 70.44%, diagnostic OR 1.69 and overall accuracy of 57.84%). A weak positive correlation is seen between IN and CL (Pearson’s correlation R = 0.181). Multi-variable binary logistic regression analysis suggested that SRs at IN (Adjusted OR − 0.259 CI 0.079–0.850), AN (Adjusted OR 0.182 CI 0.034–0.963), Multiple Pregnancy (Adjusted OR 3.5 CI 1.51–8.13) and previous sPTD/PPROM (Adjusted OR 2.72 CI 0.97–7.61) independently predicted sPTD. Conclusions TVS CSE performed better than CL as an independent predictive tool toward sPTD, although predictive efficacy was modest at best. Since technology is now available in high-end USG machines in tertiary care centers, we propose optimal utilization of CSE in LMICs to triage at-risk populations since low SRs are strongly associated with sPTD.

Histological differences in cartilage layer growth at various tendon and ligament insertions in rabbits.

Objectives: Histological differences in cartilage layer growth in Achilles tendon (AT), quadriceps tendon (QT), patellar tendon (PT), and anterior cruciate ligament (ACL) insertion are unclear. Therefore, this study aimed to investigate the differences in cartilage layer growth in AT, QT, PT, and ACL insertions. Materials and Methods: Forty-eight male Japanese white rabbits were used. Six animals were euthanized at different stages (day 1 and 1, 2, 4, 6, 8, 12, and 24 weeks). Safranin O-stained glycosaminoglycan (GAG) production area, chondrocyte count, and insertion width were investigated. Results: A two-way analysis of variance (ANOVA) revealed a significant difference in the main effects of time and insertion for all parameters. In addition, the time × insertion interaction was significant. Multiple comparisons showed a significant difference between the ACL insertion and all other variables; however, the GAG production area was not significantly different for the QT, PT, and AT insertions. AT insertions were significantly different from all other groups; however, the number of chondrocytes and insertion width were not significantly different for ACL, QT, and PT insertions. Conclusion: Cartilage layer growth differed between the AT, QT, PT, and ACL insertions. The differences between the insertions may also be due to the differences in their structures, locations, and mechanical environments.

DEVELOPMENT OF AN OPEN-SOURCE FINITE ELEMENT ANKLE MODEL FOR IN-SILICO INVESTIGATION OF THE ANKLE JOINT

AbstractObjectivesThis abstract provides an update on the Open Ankle Models being developed at the University of Bath. The goal of this project is to create three fully open-source finite element (FE) ankle models, including bones, ligaments, and cartilages, appropriate musculoskeletal loading and boundary conditions, and heterogeneous material property distribution for a standardised representation of ankle biomechanics and pre-clinical ankle joint analysis.MethodsA computed tomography (CT) scan data (pixel size of 0.815 mm, and slice thickness of 1 mm) was used to develop the 3D geometry of the bones (tibia, talus, calcaneus, fibula, and navicular). Each bone was given the properties of a heterogeneous elastic material based on the CT greyscale. The density values for each bone element were calculated using a linear empirical relation, ρ= 0.0405 + (0.000918) HU and then power law equations were utilised to get the Young's Modulus value for each bone element [1]. At the bone junction, a thickness of cartilage ranging from 0.5–1 mm, and was modelled as a linear material (E=10 MPa, ν=0.4 [2]). All ligament insertions and positions were represented by four parallel spring elements, and the ligament stiffness and material attributes were applied in accordance with the published literature [2]. The ankle model was subjected to static loading (balance standing position). Four noded tetrahedral elements were used for the discretization of bones and cartilages. All degrees of freedom were restricted at the proximal ends of the tibia and fibula. The ground reaction forces were applied at the underneath of the calcaneus bone. The interaction between the cartilages and bones was modelled using an augmented contact algorithm with a sliding elastic contact between each cartilage. A tied elastic contact was used between the cartilages and the bone. FEbio 2.1.0 (University of Utah, USA) was used to construct the open-source ankle model.ResultsWhen the double-legged stance phase loading condition was taken into consideration, stress at the antero-medial tibial wall (ranged from 1 to 7 MPa) was found to be similar to the prior work [2], indicating bulk of the load transfer was through this region. The maximum principal strain was predicted at the different regions on bones around the ankle joint. The proximal surface of the talus, and tibial distal surface were shown to have the highest maximum principal strains followed by antero-medial walls of the tibia bone, at the proximal location.ConclusionsThe present open 3D FE model of the ankle will assist researchers in better understanding ankle biomechanics, precisely predicting load transfer, and examining the ankle to address unmet clinical needs for this joint. The results of the current investigation are realistic in terms of load transfer and stress-strain distribution across the ankle joint and well comparable to those reported in the literature [2]. However, sensitivity and ankle instability simulations will be performed in future work to investigate the model's reliability and robustness.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Modified gastrocnemius splitting anatomic approach to the tibial plateau. Medium-term evaluation

BackgroundPosterior tibial plateau fractures, including avulsion fractures of the posterior cruciate ligament (PCL) insertion, represent a challenge for the orthopedic trauma surgeon. These injuries have gained a new perspective both diagnostically and therapeutically after the regular use of multiplanar computed tomography. In the herein study, we describe the outcome of patients sustaining a tibial plateau fracture with posterior articular involvement treated by open reduction and internal fixation (ORIF) using our modified gastrocnemius splitting anatomic approach. MethodsThis observational retrospective descriptive study was conducted at Complejo Medico de la Policia Federal Argentina Churruca-Visca. All patients were treated by ORIF by our team through our modified gastrocnemius splitting anatomic approach, and followed-up for a minimum of 12 months. ResultsA total of 18 patients sustaining plateau fracture were treated by this approach. Satisfactory tomographic reduction with articular gap and/or step-off <2 mm was achieved in 16. The mean time to the return to activities of daily living was 192.2 days. ConclusionThe modified gastrocnemius splitting anatomic approach represents a good alternative for the management of tibial plateau fractures involving the posterior quadrants.

Cranial tibial translation measurements for radiographic diagnosis of cranial cruciate ligament rupture in dogs.

To assess the effect of tibial compression on radiographic cranial tibial translation measurements in healthy dogs and those with cranial cruciate ligament (CCL) rupture and establish specific criteria for the radiographic diagnosis of CCL rupture. 60 dogs. Dogs were divided into 3 groups with 20 dogs each: group 1, healthy adult dogs; group 2, adult dogs with CCL rupture; and group 3, healthy young dogs. For each dog, 2 images of the stifle joint in mediolateral projection were taken, of which 1 was conventional and 1 was under tibial compression. Variables were measured in each radiographic projection: the patellar ligament angle, the patellar ligament insertion angle, the angle of tibial translation measured by 2 different methods, and the linear distance between the points of CCL origin and insertion (DPOI). Additionally, a novel variable, DPOI ratio, was evaluated. Regarding radiographic positioning, tibial compression significantly changed most of the variables in the within-group comparison. The variable DPOI were not different with and without tibial compression in the group of healthy adult dogs but were different for dogs with CCL rupture. Thus, these are important parameters in the diagnosis of CCL rupture. In the analysis of a novel variable, DPOI ratio, dogs with CCL rupture could be distinguished from healthy dogs at a high level of specificity and sensitivity. DPOI ratio values above 1.18 were consistently indicative of CCL rupture, thus allowing for a precise radiographic diagnosis of the condition.

Bone marrow edema at ligament insertion is an accurate MRI sign of deltoid ligament injury.

Magnetic resonance imaging (MRI) is effective in diagnosing deltoid ligament (DL) injury but its sensitivity in chronic cases is low. Additional diagnostic signs are required to reduce the risk of a false negative diagnosis. To evaluate the added diagnostic value of bone marrow edema at the ligament insertion (BMELI) of DL to the MRI assessment of chronic DL injury. One hundred patients who consecutively came to our institution between November 2018 and December 2021 and underwent arthroscopic surgery for chronic ankle instability (CAI) were enrolled in the present study. Preoperative MR images were retrospectively reviewed by two orthopedic surgeons to evaluate the sensitivity, specificity and interobserver reliability of three MRI signs in diagnosing chronic DL injury, namely, abnormal ligamentous morphological characteristics (ALMC), BMELI and medial clear space (MCS). Taking arthroscopy as the reference standard, there were 34 patients with and 66 without DL injury. ALMC had 64.71% (22/34; 46.47-79.70) sensitivity and 83.33% (55/66; 71.71-91.00) specificity, BMELI had 70.59% (24/34; 52.33-84.29) sensitivity and 95.45% (63/66; 86.44-98.82) specificity and MCS had 26.47% (9/34; 13.51-44.65) sensitivity and 92.42% (61/66; 82.50-97.18) specificity. Compared with ALMC, BMELI had similar efficacy in superficial cases (P = 0.06) and greater efficacy in deep cases (P = 0.04). All three signs showed good interobserver agreement (kappa values all above 0.7). BMELI can reliably indicate concomitant injury to the DL in CAI patients. Using BMELI as a sign of chronic DL injury when ALMC is unclear may reduce the risk of a false negative diagnosis.