Ligament Length Research Articles

Length Changes in Scapholunate Interosseous Ligament With Resisted Wrist Radial and Ulnar Inclination.

To investigate the changes in length of the scapholunate interosseous ligament (SLIL) when the wrist is resisting horizontal lateral load and the forearm is in full pronation invivo. We obtained computed tomography scans of the wrists of 6 volunteers in 3 situations: 0° position (0° extension and 0° ulnar inclination) and full forearm pronation without force, and in the same position but with resisted ulnar and radial deviation. Nine zones of 3 subregions of the SLIL were measured and analyzed with computer modeling. Changes in length of the palmar SLIL with resisted ulnar deviation were significantly greater than those without an applied lateral load. In contrast, the changes in length of the dorsal SLIL with resisted radial deviation were statistically greater than those in the 0° position without loading. However, no significant differences in the changes in length of the proximal SLIL werefound in any of 3 situations, except the dorsal zone with resisted radial deviation. Application of lateral load has an effect on the separation of the palmar and dorsal insertions of the SLIL. The palmar subregion of the SLIL was more highly strained with wrist-resisted ulnar deviation. Conversely, the dorsal subregion of the SLIL was under greater tension with wrist-resisted radial deviation. For patients undergoing nonsurgical treatment of SLIL tears, a sudden contraction of ulnar or radial deviation agonist muscles may be harmful and contribute to SLinstability.

Strength and failure characteristics of sandstone containing two circular holes filled with two types of inclusions under uniaxial compression

Plate shaped sandstones containing two fabricated circular holes that were filled with gypsum and high-strength concrete respectively were prepared for studying the effects of ligament length L ligament incline angle α, as well as filling modes on their strength properties and failure modes. The results show that the initial cracks can be categorized as wing crack, axial tensile crack and curved tensile crack. The failure modes of ligaments can be categorized as mode of single inclined crack, mode of single axial crack and mode of two parallel cracks. The final failure modes of all specimens can be categorized as the tension-shear mixed failure and shear failure. The strength of inclusions shows little influence on the final failure modes of specimens, while the failure modes vary with L and α. When α is a fixed value, the peak strength σ c and elastic modulus E c of tested specimens increase firstly with increasing L and reaches to the maximum value at L of 16 mm, then declines. When L is a fixed value, σ c declines firstly and then turns to increase as α increases to 75° from 45°, while E c increases linearly. The axial stress σ p performs the similar variation trends with those of σ c versus increasing L and α when ligaments fail.

432 - Long Utero-Ovarian Ligament Length Might be a Risk Factor for Ovarian Torsion: a Prospective Study

Study Objective: To evaluate whether there is an association between utero-ovarian ligament (UOL) length and ovarian torsion.

Anatomic ligament consolidation of the superior acromioclavicular ligament and the coracoclavicular ligament complex after acute arthroscopically assisted double coracoclavicular bundle stabilization.

The consolidation of the acromioclavicular (AC) and coracoclavicular (CC) ligament complex after arthroscopically assisted stabilization of acute acromioclavicular joint (ACJ) separation is still under consideration. Fifty-five consecutive patients after arthroscopically assisted double-CC-bundle stabilization within 14days after acute high-grade ACJ separation were studied prospectively. All patients were clinically analysed preoperatively (FU0) and post-operatively (FU1=6months; FU2=12months). The structural MRI assessments were performed at FU0 (injured ACJ) and at FU2 bilateral (radiologic control group) and assessed separately the ligament thickness and length at defined regions for the conoid, trapezoid and the superior AC ligament. Thirty-seven patients were assessed after 6.5months and after 16.0months. The 16-month MRI analysis revealed for all patients continuous ligament healing for the CC-complex and the superior AC ligament with in the average hypertrophic consolidation compared to the control side. Separate conoid and trapezoid strands (double-strand configuration) were detected in 27 of 37 (73%) patients, and a single-strand configuration was detected in 10 of 37 (27%) patients; both configurations showed similar CCD data. The ligament healing was not influenced by the point of surgery, age at surgery and heterotopic ossification. The clinical outcome was increased (FU0-FU2): Rowe, 47.7-97.0 pts.; TAFT, 3.9-10.6 pts.; NAS pain, 8.9-1.4 pts. (all P<0.05). The arthroscopically assisted double-CC-bundle stabilization within 14days after acute high-grade ACJ separation showed 16months after surgery sufficient consolidations of the AC and double-CC ligament complex in 73%. III, Case series.

InVivo 3-Dimensional Kinematics of Thumb Carpometacarpal Joint During Thumb Opposition.

This study primarily aimed to demonstrate the screw-home rotation of the thumb carpometacarpal (CMC) joint and the function of surrounding ligaments during thumb oppositional motion. A 3-dimensional kinematic analysis of the thumb CMC joint was conducted using data derived from computed tomography of 9 healthy volunteers. Scans were obtained in the neutral forearm and wrist position and the thumb in maximum radial abduction, maximum palmar abduction, and maximum opposition. The movements of the first metacarpal and the palmar and dorsal bases on the trapezium during thumb oppositional motion from radial abduction through palmar abduction were quantified using a coordinate system originating on the trapezium. In addition to the kinematic analyses, the length of virtual ligaments, including the anterior oblique, ulnar collateral, dorsal radial, dorsal central (DCL), and posterior oblique ligament (POL), were calculated at each thumb position. From radial abduction to opposition of the thumb through palmar abduction, the first metacarpal was abducted, internally rotated, and flexed on the trapezium. The palmar base of thefirst metacarpal moved in the palmar-ulnar direction, and the dorsal base moved in the palmar-distal direction along the concave surface of the trapezium. Although the DCL and POLlengthened, the lengths of other ligaments did not change significantly. During thumb oppositional motion, internal rotation of the first metacarpal occurred, with the palmar base rotating primarily with respect to the dorsal base. The DCL and POL may be strained in thumb functional positions. Kinematic variables indicated a screw-home rotation of the thumb CMC joint and the contribution of the dorsal ligaments to the stability of the rotation on the pivot point.

Ultrasonographic identification of the dorsal atlantoaxial ligament in dogs.

To determine the ability to identify the dorsal atlantoaxial ligament during ultrasonographic examination of dogs. Canine cadaveric study. Canine cervical spines (n = 35). Thirty-five canine cadavers with an estimated body weight of 6-35 kg were retrieved. Five cervical spines were dissected to assess the length and thickness of the dorsal atlantoaxial ligament and correlate ultrasound-guided injection of ink with anatomical dissection. Ultrasonographic evaluation of the dorsal atlantoaxial ligament was performed on 30 cadavers. The visibility of the dorsal atlantoaxial ligament in both the transverse and the sagittal planes was subjectively scored (0-3). The dorsal atlantoaxial ligament was detectable on ultrasonographic examination in all cadavers: 27/30 and 28/30 were graded as moderately visible (grade 2) or clearly visible (grade 3) in the sagittal and transverse view, respectively. Only 1/30 cadaver specimen of a large breed dog was graded as 1 (indistinct) in both the sagittal and transverse planes. None of the cadavers were graded as 0 (not visible) in any view. The dorsal atlantoaxial ligament can be identified in ultrasonographic examination of normal canine cadavers. Future studies on animals with clinical atlantoaxial instability/subluxation are needed to evaluate the role of this imaging technique in providing a safer diagnosis of this condition. Ultrasonographic examination of the dorsal atlantoaxial ligament could potentially provide a noninvasive and safe imaging technique that may contribute to the diagnosis of atlantoaxial instability/subluxation in dogs.

Morphological similarity and structure-dependent scaling laws of nanoporous gold from different synthesis methods

Application of the foam scaling laws to the mechanical properties of nanoporous gold (np-Au) implicitly assumes geometrical similarity of structures of different relative density and synthesis methods. While the very few studies addressing the issue of geometric similarity during thermal coarsening show contradicting results, there are no studies covering np-Au from different synthesis routes. This paper performs quantitative morphological and topological comparison of np-Au of ca. 30% relative density synthesized by free and electrochemical corrosion methods, and thermally coarsened samples. Nanoindentation tests were performed to obtain elastic modulus and hardness. Uniaxial compression simulations of three-dimensional structures from FIB-nanotomography have been conducted using finite element analysis, and the results are compared with experiments. The three-dimensional np-Au structure has been quantified in terms of the ligament diameter and length distributions, ligament tortuosity, surface curvature distributions, structural anisotropy, nodal connectivity, and genus. Our results suggest that neither the synthesis route nor the thermal coarsening, to change length scale by up to a factor of 3, significantly altered the morphology and topology. The modulus and strength from both experiment and simulations exhibit a linear dependency on the scaled genus density, modifying the geometry-dependent prefactors in the Gibson and Ashby scaling relations.

Crack Initiation and Coalescence Behavior of Two Non-parallel Flaws

Crack initiation and coalescence behavior of rock or rock-like specimens containing artificial flaws under uniaxial compression have been subjects of intensive investigation in the past. Most of these investigations however focused on crack initiation and coalescence between two or more parallel flaws. Although there have been few experimental studies on non-parallel flaws, these studies did not address the influence of geometrical factors such as ligament length and ligament angle on the crack initiation and coalescence behavior of non-parallel flaws. To investigate whether the individual geometrical factors have similar effects on the crack initiation and coalescence behavior of both parallel and non-parallel flaws, we conducted uniaxial compression tests to investigate crack cracking and coalescence processes in rock like material containing two non-parallel flaws. The paper presents the influence of individual geometrical factors on the crack initiation process and coalescence pattern of non-parallel flaws. Initiation of primary first cracks from all the tips of the two flaws did not occur simultaneously in all the flaw configurations. The flaw configuration of the non-parallel flaws influences the crack initiation, crack trajectories and coalescence behavior. The crack coalescence pattern changes with an increasing ligament angle from indirect to shear crack or mixed tensile-shear crack to tensile crack coalescence. The chance of direct coalescence is reduced with an increase in ligament length. In conclusion, the crack initiation and coalescence behavior of prismatic rock-like specimens with non-parallel flaws, as influenced by the geometrical factors, are analogous to the cracking and coalescence pattern observed in specimens with parallel flaws.

The Location of Anterior Cruciate Ligament Tears: A Prevalence Study Using Magnetic Resonance Imaging.

Background:Over the past decade, there has been a resurgence of interest in anterior cruciate ligament (ACL) preservation. Proximal and distal avulsion tears have been treated with arthroscopic primary repair, while augmented repair, remnant tensioning, primary repair with biological scaffold, and remnant preservation have been proposed for different types of midsubstance tears. Currently, the incidence of these different tear types is unknown.Purpose:To propose a magnetic resonance imaging (MRI) classification system for different tear types based on clinical relevance and to assess the distribution of these different ACL tear types.Study Design:Case series; Level of evidence, 4.Methods:A retrospective search in an institutional radiographic database was performed for patients who underwent knee MRI at our institution between June 2014 and June 2016. Patients younger than 18 years and those with reports of chronic tears, partial tears, multiligamentous injuries, were excluded. Tear types were graded as proximal avulsion (distal remnant length >90% of total ligament length, type I), proximal (75%-90%, type II), midsubstance (25%-75%, type III), distal (10%-25%, type IV), and distal avulsion (<10%, type V). An orthopaedic surgeon, a radiologist, and a research fellow graded the tear type on 30 MRIs to determine reliability, and the research fellow graded all MRIs. Inter- and intraobserver reliability were measured using kappa statistics.Results:A total of 353 patients (57% male; mean age, 37.1 years; range, 18.1-81.2 years) were included. Interobserver reliability was 0.670 (95% confidence interval, 0.505-0.836), and intraobserver reliability ranged from 0.741 to 0.934. Incidence of type I tears was 16%, type II tears 27%, type III tears 52%, type IV tears 1%, and type V tears 3% (2.5% with bony avulsion). Type I tears were more common in patients older than 35 years compared with those younger than 35 years (23% vs 8%; P < .001).Conclusion:This classification system was reliable in assessing tear location in acute ACL injuries. Type I tears were seen in 16%, type II in 27%, and type III in 52% of patients in our cohort. These data suggest that there may be greater potential application for ACL preservation techniques.

Numerical experiments on effect of morphology on wave propagation in nanoporous materials

ABSTRACTMechanics of nanoporous metallic materials have been an interest due to their applications in a wide range of areas such as sensors, energy conversion, and smart materials design. In this study, the effects of morphological parameters, such as ligament diameter and length, on wave propagation in bicontinuous porous nanostructures is studied by using the discontinuous Galerkin method. Computational results show that energy is localized on the surface independent of the morphological parameters. It is observed that localization length increases with the increase in frequency. In addition, surface roughness parameter and ligament diameter do not have a significant influence on localization length.

Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children.

Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children. A total of 141 children under 12 years old who had undergone lumbar-sacral magnetic resonance imaging were included. The T2 sagittal image that provided the best view of the sacrococcygeal membrane and the dural sac was chosen. We used Picture Achieving and Communication System (Centricity® PACS, GE Healthcare Co.) to measure the distance between the sacrococcygeal ligament and the dural sac, the length of the sacrococcygeal ligament, and the maximum depth of the caudal space. There were strong correlations between age, weight, height, and BSA, and the distance between the sacrococcygeal ligament and dural sac, as well as the length of the sacrococcygeal ligament. Based on these findings, a simple formula to calculate the distance between the sacrococcygeal ligament and dural sac was developed: 25 × BSA (mm). This simple formula can accurately calculate the safe depth of the caudal epidural space to prevent unintended dural puncture during caudal block in children. However, further clinical studies based on this formula are needed to substantiate its utility.

A novel essential work of fracture experimental methodology for highly dissipative materials

Determining fracture toughness for soft, highly dissipative, solids has been a challenge for several decades. Amongst the limited experimental options for such materials is the essential work of fracture (EWF) method. However, EWF data are known to be strongly influenced by specimen size and test speed. In contrast to time-consuming imaging techniques that have been suggested to address such issues, a simple and reproducible method is proposed. The method accounts for diffuse dissipation in the specimen while ensuring consistent strain rates by scaling both the sample size and testing speed with ligament length. We compare this new method to current practice for two polymers: a starch based food and a polyethylene (PE) tape. Our new method gives a size independent and more conservative fracture toughness. It provides key-data, essential in numerical models of the evolution of structure breakdown in soft solids as seen for example during oral processing of foods.

Short-term effects of arthrotomy with and without infrapatellar fat pad resection on the normal canine stifle.

To investigate the short-term effects of infrapatellar fat pad (IFP) resection in normal dogs. Experimental in vivo study. Five normal adult female beagle dogs. The IFP was resected via arthrotomy in the left stifle joint (experimental side) while the right stifle underwent arthrotomy alone (sham side). An orthopedic examination was performed every week for 4 weeks and synovial fluid was analyzed before and 4 weeks after the procedure. The ratio of the length of the patellar ligament to the patellar length (L:P) was calculated on a lateral radiograph of the stifle before, 2 and 4 weeks after the procedure. Patellar depth (PD) and the contact area (CA) between the femur and patella were calculated from computed tomographic images taken at 3 different stifle angles (extended, flexed, hyperflexed) before, immediately after, and 4 weeks following the procedure. The dogs were euthanatized 4 weeks after the procedure for macroscopic and microscopic evaluation of the patellofemoral joint. No difference was found between treatment groups throughout the study. No evidence of postoperative osteoarthritis was detected in any of the dogs. Orthopedic examinations, radiographs, and synovial fluid analyses remained within normal limits. Most PD, but not CA measurements, increased with time in both joints and at all stifle angles. Excision of the IFP subsequent to medial arthrotomy did not result in any measurable changes in the canine patellofemoral joint when compared with medial arthrotomy alone after 4 weeks of follow-up.

The oblique popliteal ligament: an anatomic and MRI investigation.

Despite being the largest ligament on the posterior aspect of the knee, relatively little is known about the normal morphology of the oblique popliteal ligament (OPL). The aim of this study was to investigate the detailed anatomy of the OPL in cadavers and healthy volunteers. The posterior knee was investigated in 25 cadaver lower limbs (mean age 76 ± 9.5 years; 7 men) by dissection, histology, and serial plastination and in 14 healthy individuals (mean age 23 ± 3.2 years; 11 men) using magnetic resonance (MR) imaging. OPL morphology, attachments sites, ligament length and width, relationship to surrounding structures and histological composition were recorded. Intraobserver reliability was assessed using intraclass correlation coefficients. The OPL is a distinct expansion of the semimembranosus (SM) tendon and sheath, which courses superolaterally to attach to the posterolateral joint capsule or fabella (when present), at the medial margin of the lateral femoral condyle. The ligament blends with the joint capsule medially and laterally, serves as an attachment site for plantaris, and has connections with popliteus. In 70% of dissections, the OPL divided into two bands, separated by small branches of the middle genicular neurovascular bundle that pierced the posterior joint capsule. Differences in mediolateral length were noted between dissection and MR imaging (43.6 ± 6.2 vs. 57.6 ± 4.4mm; p < 0.001). At its medial and lateral attachments, the OPL was 23.2 ± 6.9 and 17.4 ± 8.7mm wide (proximodistal), respectively. The OPL was predominantly composed of transverse collagen layers, with little elastin. While visible on axial MR scans, delineation of its most lateral extent was difficult. Repeatability of selected measurements ranged from good to almost perfect. The OPL is a distinct ligament with identifiable anatomical limits. Based on its morphological characteristics, it appears more tendinous than ligamentous in nature. A better understanding of the OPL may help define its importance in the assessment and treatment of posterior knee injuries.

The forgotten joint: quantifying the anatomy of the proximal tibiofibular joint.

Limited objective data exist detailing the quantitative anatomy of the individual bundles of the proximal tibiofibular joint and their relation to surgically pertinent osseous landmarks. The purpose of this study was to qualitatively and quantitatively describe the ligamentous anatomy of the proximal tibiofibular joint and its relation to relevant bony landmarks. Ten non-paired, fresh-frozen cadaveric knee specimens were dissected to identify the proximal tibiofibular joint ligament bundles. Pertinent bony landmarks were identified and served as reference points for the tibial and fibular attachments for each bundle. Ligament bundle footprints, lengths and orientations were measured using a 3D coordinate measuring device. Up to four bundles were identified anteriorly and up to three bundles posteriorly. The inferior bundle was identified anteriorly and posteriorly in 60% and 20% of the cases, respectively. For the anterior complex, the centres of the tibial attachments were a mean distance of 12.5mm (95% CI [10.7, 14.3]) and 25.3mm (95% CI [21.6, 29.0]) from the tibial plateau for the superior and inferior bundles, respectively. The centres of the fibular attachments were 11.3mm (95% CI [7.4, 15.1]) and 27.0mm (95% CI [24.0, 30.0]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. For the bundles of the posterior complex, the centres of the tibial attachments were 13.4mm (95% CI [11.6, 15.2]) and 38.8mm (95% CI [31.0, 46.6]) distal to the tibial plateau for the superior and inferior bundles, respectively, and the centres of the fibular attachments were 8.0mm (95% CI [5.8, 10.1]) and 29.3mm (95% CI [25.5, 33.1]) from the apex of the fibular styloid for the superior and inferior bundles, respectively. In the coronal plane, the mean 2D angle between the medial to lateral knee joint axis and the axis passing through the centre of the proximal tibiofibular joint and the centre of the tibial plateau was 16.9° (95% CI [12.8, 21.0]). The ligament bundles of the proximal tibiofibular joint were reproducibly identified between specimens in relation to surrounding bony landmarks. Up to four bundles were identified in the anterior ligament complex and up to three in the posterior complex. Variation in bundle orientation and footprint size was observed. Based on these findings, an anatomic reconstruction can be performed using surrounding reliable landmarks.

Size and boundary effects on notch tensile strength and fracture properties of PMMA bone cement

Poly (methyl methacrylate) bone cement is widely used for anchoring total joint replacements. In such an application, tensile and fracture properties of the cement are particularly important as they have strong implications for the stability of the implant in the bone bed and, hence, its life. Being a quasi-brittle material, it is to be expected that any mechanical property of bone cement would be size-dependent. This issue has not been addressed in the literature. In the present work, tests using modified wedge-splitting specimens were carried out to determine the size and boundary effects on the notch tensile strength (σNT) and on two fracture parameters, namely, specific fracture energy (Gf), and characteristic length based on the notch tensile strength (lchspl) of a widely used approved brand, Palacos® R. Size and boundary effects, of varying magnitudes, on each of these properties were found. For example, 1) for geometrically-similar specimens (specimen height (W) was varied from 15 mm to 36 mm but ratio of length of the starter crack (a) to W was fixed), the general trend was marked decrease in σNT with increase in W for a given a/W; and 2) for identical-sized specimens (W was fixed but a/W was varied from 0.06 to 0.81), the general trend was moderate decrease in Gf with increase in a/W for a given W. A validated boundary effect model presented in the literature and results from some of the specimens used in the present experimental work were used to compute the size-independent specific fracture energy and transition ligament length of the cement brand to be 2096 N m−1 and 4 mm, respectively.

In vivo metacarpophalanageal joint collateral ligament length changes during flexion.

We investigated the in vivo length changes of the collateral ligaments of metacarpophalangeal joint during flexion. We obtained computed tomography scans of index, middle, ring and little fingers at 0°, 30°, 60° and 90° of joint flexion from six hands of six healthy adult volunteers. Three of them had their dominant right hand studied, and the other three had their non-dominant left hand studied. We measured and analysed the radial and ulnar collateral ligaments of each metacarpophalangeal joint from the reconstructed images. We found that the dorsal and middle portions of the both radial and ulnar collateral ligament lengthened progressively during digital flexion and reached the maximum at 90° flexion. The length of the volar portion increased from 0° to 30° flexion and then decreased from 30° to 60° flexion, reaching the minimum at 90°. In conclusion, three portions of collateral ligaments on both sides of the metacarpophalangeal joint have variable length changes during flexion, which act to stabilize the joint through its flexion arc.

Statistical analysis of the influence of microstructure on damage in fibrous ceramic matrix composites

AbstractThe effect of microstructure on cracking was analyzed in a CMC using statistical methods. It was determined that the amounts of coating surrounding fibers and their dispersion within the matrix influenced where cracks evolved in transverse plies. Linear models predicted that maximum principal strains in transverse fiber coatings increased as (i) the fiber coating area increased and (ii) the length of matrix ligament between fibers decreased. Logistic models indicated that the likelihood of transverse fibers residing on a matrix crack increased as the (i) ratio of coating to filament decreased, (ii) distance between fibers decreased, or (iii) coating area increased.

Evolution of defects in nanoporous gold with annealing temperature using low-energy positron beam experiments

Defects in nanoporous gold (np-Au) samples, prepared by selective dissolution of silver from a binary Ag75Au25 alloy, with annealing temperature have been investigated using the positron beam Doppler line shape S-parameter. It is shown that there is an initial formation of vacancy clusters arising due to the aggregation of thermally migrating vacancies up to 473 K, followed by the breakup of these clusters at higher temperatures, coincident with the rapid growth of ligaments. In addition to the defect-specific S-parameter, the low-energy positron beam experiments have also been used to evaluate the variation of the effective positron diffusion length in np-Au with annealing temperature. The variation of effective positron diffusion length with the ligament diameter, d, scales as which points to the diffusion of positrons along the ligament length, that is also substantiated through measurement of the positronium fraction.

FPZ evolution of mixed mode fracture in concrete: Experimental and numerical

Abstract Digital image correlation (DIC) technique is applied to study the evolution of fracture process zone (FPZ) of mixed mode fracture in concrete. By testing a series of beams of various sizes under four-point shearing, the opening and sliding displacements on the crack surfaces are derived using the DIC technique. Meanwhile, a numerical method is employed to simulate the fracture process by introducing a crack propagation criterion. The opening and sliding displacements on the crack surfaces obtained from numerical analysis exhibit a reasonable agreement with the experimental results, which verifies the DIC technique presented in the study. By combining experimental observations with numerical simulations, the evolution of the FPZ during the whole crack propagation process of mix mode fracture is investigated and elaborated in depth. The results indicate that the ratio of crack opening to sliding displacement remains approximately constant as crack propagates before reaching a peak load. Meanwhile, the FPZ evolution during the complete fracture process is influenced by the specimen ligament length and the ratio of mode I to II stress intensity factor component. With the decrease of ligament length and the ratio of mode I to II stress intensity factor component, the full FPZ length decreases. However, when the ligament length is less than 63 mm or ratio of mode I to II stress intensity factor component is less than 0.11, the FPZ cannot fully develop, but keeps increasing as crack propagates.