Ligament Failure Research Articles

A Systematic Review of Treatment Strategies for the Prevention of Junctional Complications After Long-Segment Fusions in the Osteoporotic Spine.

Study Design:Systematic reviewObjectives:Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are well-known complications after long-segment fusions in the thoracolumbar spine of osteoporotic patients. Recent advances in anti-resorptive and anabolic medications, instrumentation, surgical technique, and cement augmentation have all aided in the avoidance of junctional kyphosis. In this article, current literature on the prevention of PJK and PJF in the osteoporotic spine is reviewed.Methods:A systematic literature review was conducted using the PubMed/MEDLINE and Embase databases in order to search for the current preventive treatment methods for PJK and PJF published in the literature (1985 to present). Inclusion criteria included (1) published in English, (2) at least 1-year mean and median follow-up, (3) preoperative diagnosis of osteoporosis, (4) at least 3 levels instrumented, and (5) studies of medical treatment or surgical techniques for prevention of junctional kyphosis.Results:The review of the literature yielded 7 studies with low levels of evidence ranging from level II to IV. Treatment strategies reviewed addressed prophylaxis against ligamentous failure, adjacent vertebral compression fracture, and/or bone-implant interface failure. This includes studies on the effect of osteoporosis medication, cement augmentation, multi-rod constructs, and posterior-tension band supplementation. The role of perioperative teriparatide therapy maintains the highest level of evidence.Conclusions:Perioperative teriparatide therapy represents the strongest evidence for preventive treatment, and further clinical trials are warranted. Use of cement augmentation, sublaminar tethers, and multi-rod constructs have low or insufficient evidence for recommendations. Future guidelines for adult spinal deformity correction may consider bone mineral density–adjusted alignment goals.

Numerical study of interfiber ligament failure of composites wth ductile bulk matrices

Debonding of fiber/matrix interfaces, kinking on debonded matrix surfaces, and tearing of interfiber ligaments are three major failure modes in micro-scales often observed in the failure experiments of Fiber Reinforced Composites (FRC) under extreme transverse tensile loadings. Numerical simulations on these complex failure processes at micro-scales are critical for designing new FRC materials. However, it is difficult to simultaneously simulate all these failure modes especially for cases where bulk matrix materials are ductile and undergo large plastic deformation. To overcome this difficulty, we adopt an innovative DG-based interface-oriented finite element technique that is able to handle all three failure modes. In this paper, using this numerical technique, we successfully simulate a complete failure process characterized by all three fracture modes for a composite structure containing two fibers embedded in a ductile bulk matrix. Furthermore, the kinking of debonded matrix surfaces predicted from simulations agrees well with the experimental results. Finally, we have studied the impact of variation in the thickness of interfiber ligaments on the failure behaviors of FRC materials. By running four cases with varied ligament thicknesses, we have identified a beam-like mixed bending/shearing failure mode for the tearing of interfiber ligaments and the shearing influence on the failure may increase following the increase in ligament thickness.

Plantar fasciitis: Talonavicular instability/spring ligament failure as the driving force behind its histological pathogenesis

The aetiology of plantar fasciitis (PF) remains uncertain and to date, it is not known if there is an association with spring ligament laxity. In this study, 28 patients with unilateral plantar fasciitis were evaluated. A digital Klaumeter was used to assess first ray for instability and lateral plane translation was used as a measure of spring ligament laxity in the affected vs unaffected foot (internal control). Retromalleolar tenderness as a sign of a reactive tibialis posterior tendon was also assessed. The mean lateral translation score for symptomatic feet was 67.2 (95% CI [63.26−71.14]), compared to asymptomatic feet mean of 33.0 (95% CI [27.35−38.65] p < 0.05). The mean TMT instability score for symptomatic feet was 11.3 (95% CI [10.29–12.3]), compared to the asymptomatic feet mean of 5.9 (95% CI [4.49−7.31] p < 0.05). 100% of symptomatic feet had a retromalleolar tenderness over the tibialis posterior compared to 14% of asymptomatic feet. This is the first study to demonstrate a statistically significant increase in spring ligament strain in feet affected with PF using internal controls. The study postulates that tensile overload at the medial plantar fascia develops secondary to spring ligament failure regardless of foot shape. Furthermore, this condition can be regarded as an early warning sign of adult acquired flat foot disorder (AAFD). Future treatments for PF should not further destabilise the medial arch. This understanding may allow development of new treatment strategies in restoring spring ligament integrity to offload the plantar fascia strain.

Update on the Biomechanics of the Craniocervical Junction, Part II: Alar Ligament.

Study Design:In vitro biomechanical study.Objective:The strength of the alar ligament has been described inconsistently, possibly because of the nonphysiological biomechanical testing models, and the inability to test the ligament with both attachments simultaneously. The purpose of this biomechanical model was to reevaluate the alar ligament’s tensile strength with both bony attachments, while also keeping the transverse ligament intact, all in a more physiological biomechanical model that mimics the mechanism of traumatic injury closely.Methods:Eleven fresh-frozen occipito-atlanto-axial (C0-C1-C2) specimens were harvested from individuals whose mean age at death was 77.4 years (range 46-97 years). Only the alar and transverse ligaments were preserved, and the bony C0-C1-C2 complex was left intact. Axial tension was exerted on the dens to displace it posteriorly, while the occipito-axial complex was fixed anteriorly. A device that applies controlled increasing force was used to test the tensile strength (M2-200, Mark-10 Corporation).Results:The mean force required for the alar ligament to fail was 394 ± 52 N (range 317-503 N). However, both the right and left alar ligaments ruptured simultaneously in 10 specimens. The ligament failed most often at the dens (n = 10), followed by occipital condyle rupture (n = 1). The transverse ligament remained intact in all specimens.Conclusions:When both the right and left alar ligament were included, the total alar ligament failure occurred at an average force of 394 N. The alar ligament failed before the transverse ligament.

Risk Factors for Grade 3 Pivot Shift in Knees With Acute Anterior Cruciate Ligament Injuries: A Comprehensive Evaluation of the Importance of Osseous and Soft Tissue Parameters From the SANTI Study Group

Background: Preoperative grade 3 pivot shift has been reported to be associated with higher rates of anterior cruciate ligament (ACL) failure, persistent instability, and inferior patient-reported outcomes. The etiology of a high-grade pivot shift is multifactorial, and numerous factors have been suggested to be responsible. More attention has recently been focused on injury to the anterolateral structures (ALS) as a risk factor for a grade 3 pivot shift. Purpose: To determine risk factors for grade 3 pivot shift, including soft tissue and osseous parameters. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A prospective evaluation was undertaken of 200 consecutive patients undergoing acute ACL reconstruction (within 10 days of injury). An open exploration of the lateral side of the injured knee was performed at the time of the index procedure. Details regarding patient and injury characteristics were recorded, as were details of soft tissue injuries, including meniscal tears, ALS lesions, medial collateral ligament tears, and chondral injuries. Osseous parameters (tibial slope and condylar ratios) were determined per established magnetic resonance imaging protocols. A multivariate logistic regression with penalized maximum likelihood was used to identify risk factors associated with International Knee Documentation Committee (IKDC) grade 3 pivot shift. Results: The mean ± SD age of the population was 28.3 ± 9.8 years; 67.5% of patients were male. Among patients, 35 (17.5%) had a high-grade pivot shift (IKDC grade 3), and 165 (82.5%) had a low-grade pivot shift (IKDC grades 1 and 2). Univariate and multivariate logistic regression analysis demonstrated that injury to the ALS was the only significant risk factor for grade 3 pivot shift (odds ratio, 13.49; 95% CI, 1.80-1725.53). Conclusion: This comprehensive evaluation of soft tissue and osseous factors has identified that injury to the ALS is the most important risk factor for grade 3 pivot shift in acute ACL-injured knees.

Insights into fracture mechanisms in nanoporous gold and polymer impregnated nanoporous gold

Nanoporous metals have favourable characteristics for many applications. These materials have, however, failed to show suitable attributes in tension: showing an extremely weak and brittle response. This issue has been addressed through the impregnation of a polymer constituent into the nanoporous ligament network, creating a strong and malleable material in both tension and compression. In this work, this improvement is investigated by comparing nanoporous gold and its polymer filled nanocomposite counterpart using computational microspecimen compact-tensile tests. We examine crack initiation and propagation within these materials. The micromechanical response is also explored to reveal the influence of the polymer impregnation on fracture mechanisms. It is shown that, in agreement with the findings in the literature, the failure of a few gold ligaments in nanoporous gold leads to the complete failure of the material with a relatively small resistance to failure and a characteristically brittle fracture. Polymer impregnation, on the other hand, effectively delays the complete material failure as the polymer stabilizes the individual ligaments. This results in a significantly increased ductility under tension which is vital for it to be considered for use in structural applications.

Assessment of Flexion Elongation Relation and Type of Failure after Capsulodesis.

Background Injury of the scapholunate interosseous ligament is the most frequently diagnosed cause of carpal instability and can be treated with a Mayo capsulodesis procedure. During this procedure, a radially based flap of the dorsal radiocarpal complex is attached to the lunate. The procedure attempts to reduce flexion of the scaphoid and restore the scapholunate relationship by crossing the scapholunate interval. To obtain a better understanding of the biomechanical properties and possibly improve the postoperative rehabilitation process, a better understanding of the reconstructions biomechanics is needed. Methods Ten dorsal intercarpal ligament capsulodesis were performed on embalmed wrists to assess the flexion elongation relation at the dorsal intercarpal reconstruction, the dorsal intercarpal complex, and the type of failure during flexion of the wrist. Results The mean elongation of the dorsal intercarpal reconstruction at 70-degree flexion was 0.8 mm. During flexion, the dorsal intercarpal reconstruction showed no ligament tears or failure of the bone anchor. The mean elongation of the dorsal intercarpal complex was 3.9 mm at 70 degrees. During subsequent repeated flexion, four sutures to connect the dorsal intercarpal complex to the surrounding tissue loosened between 55 and 60 degrees. Conclusions These findings suggest that capsulodesis can safely withstand flexion of the wrist until 50 degrees. Clinical Relevance Clinicians should consider the opportunity to start early with controlled active motion. Level of Evidence Not applicable.

Impact of knee recurvatum on machine-assessed muscle recovery from isokinetic after anterior cruciate ligament surgery

Recurvatum is generally considered to be a risk factor for graft tendon failure and a probable risk factor for native anterior cruciate ligament failure. To evaluate the impact of recurvatum and the type of anterior cruciate ligament repair on the hamstring/quadriceps ratio 4 months after surgery. One hundred and three patients having undergone anterior cruciate ligament surgery were included between July 1st, 2017, and July 1st, 2018. A clinical check-up and an isokinetic test were performed 4 months after surgery. The hamstring/quadriceps ratio was calculated and then assessed as a function of the type of surgery and the presence or absence of recurvatum. The mean hamstring/quadriceps ratio on the operated side did not differ significantly ( P = 0.87) when comparing patients with recurvatum (1.2) and those without (also 1.2). The interaction between the type of surgery and recurvatum was statistically significant ( P = 0.019). In patients with recurvatum, the mean hamstring/quadriceps ratio was 1.49 in the patellar tendon group and 1.04 in the hamstring ligament group. Neither the presence of recurvatum nor the type of surgery alone was related to the hamstring/quadriceps ratio on the operated side. However, the interaction between surgery and recurvatum was statistically significant. Patellar tendon technique should be preferred to the hamstring group technique in patients with recurvatum. La rupture du ligament croisé antérieur est une blessure très fréquente chez le sportif. Le recurvatum est généralement considéré comme un facteur de risque de re-rupture du greffon et un facteur de risque probable de rupture du ligament croisé antérieur natif. Évaluer l’impact du recurvatum et du type de chirurgie sur le ratio fonctionnel ischio-jambier/quadriceps 4 mois après la chirurgie. Cent trois patients opérés du ligament croisé antérieur ont été inclus entre le 1 er juillet 2017 et le 1 er juillet 2018. Un examen clinique et un test isocinétique ont été réalisés 4 mois après la chirurgie. Le ratio ischio-jambier/quadriceps a été calculé pour chaque patient, puis évalué en fonction du type de chirurgie et de la présence ou non de recurvatum. Le ratio ischio-jambier/quadriceps moyen du côté opéré ne différait pas significativement ( p = 0,87) lorsque l’on comparait les patients avec recurvatum (1,2) et ceux sans (également 1,2). L’interaction entre le type de chirurgie et le recurvatum était statistiquement significative ( p = 0,019) : chez les patients avec recurvatum, le ratio ischio-jambier/quadriceps moyen était de 1,49 dans le groupe tendon rotulien et de 1,0 dans le groupe tendons ischio-jambiers. Ni la présence de recurvatum, ni le type de chirurgie ne sont liés au ratio ischio-jambier/quadriceps du côté opéré, cependant l’interaction entre le type de chirurgie et la présence de recurvatum était statistiquement significative dans notre population. La technique du tendon rotulien devrait être préférée à celle des tendons ischio-jambiers chez les patients avec recurvatum.

More Than a 2-Fold Risk of Contralateral Anterior Cruciate Ligament Injuries Compared With Ipsilateral Graft Failure 10 Years After Primary Reconstruction

Background: Failure of anterior cruciate ligament (ACL) reconstruction or an injury to the ACL in the contralateral knee represents a devastating event for patients, especially those young and physically active. However, controversies are still present regarding long-term failure rates and risk factors. Purpose: To assess the long-term rate of ipsilateral graft failure and contralateral ACL injuries after ACL reconstruction performed at a single center using the same surgical technique with a hamstring autograft and to investigate the effect of sex, age, and preinjury activity level as predictors of second ACL injuries. Study Design: Case series; Level of evidence, 4. Methods: The study cohort consisted of 244 consecutive patients (mean age, 30.7 years) who underwent ACL reconstruction with a single bundle plus lateral plasty technique using the hamstring tendon between November 2007 and May 2009. The number of subsequent ACL injuries (ipsilateral ACL revision or contralateral ACL reconstruction) was determined at a minimum follow-up of 10 years. Survivorship of either knee and subgroup analysis included sex, age, preoperative Tegner activity level, timing of ACL reconstruction, body mass index, and smoking status. Results: Ipsilateral ACL revision was performed in 8 (3.4%) patients and contralateral ACL reconstruction in 19 (7.8%) patients. Only 1 patient had both ipsilateral and contralateral injuries. No predictors were found for ipsilateral ACL revision, while age <18 years and preoperative Tegner level ≥7 had a higher risk of contralateral ACL reconstruction. The highest rate of a second ACL reconstruction procedure was in young (<18 years) and active (Tegner ≥7) patients, in whom the 10-year survival of either knee was 61.1%. Six years after primary ACL reconstruction, the rate of contralateral ACL reconstruction was significantly higher than that of ipsilateral ACL revision (hazard ratio, 2.4-3.6). Conclusion: In the long term, a second injury to either the ipsilateral or the contralateral knee in young and active populations could reach 40%, with a more than double-fold risk of contralateral ACL reconstruction compared with ipsilateral ACL revision.

Adult Acquired Flatfoot

Acquired adult flatfoot is a three-dimensional deformation, which consists of hindfoot valgus, collapse of the longitudinal arch of the foot and adduction of the forefoot. The aim of the work is to present problems related to etiology, biomechanics, clinical diagnostics and treatment principles of acquired flatfoot. The most common cause in adults is the dysfunction of the tibialis posterior muscle, leading to the lack of blocking of the transverse tarsal joint during heel elevation. Loading the unblocked joints consequently leads to ligament failure. The clinical image is dominated by pain in the foot and tibiotarsal joint. The physical examination of the flat feet consists of: inspection, palpation, motion range assessment and dynamic force assessment. The comparable attention should be paid to the height of the foot arch, the occurrence of “too many toes” sign, evaluate the heel- rise test and correction of the flatfoot, exclude Achilles tendon contracture. The diagnosis also uses imaging tests. In elastic deformations with symptoms of posterior tibial tendonitis, non-steroidal anti-inflammatory drugs, short-term immobilization, orthotics stabilizing the medial arch of the foot are used. In rehabilitation, active exercises of the shin muscles and the feet, especially the eccentric exercises of the posterior tibial muscle, are intentional. The physiotherapy and balneotherapy treatments, in particular hydrotherapy, electrotherapy and laser therapy, are used as a support. In advanced lesions, surgical treatment may be necessary, including plastic surgery of soft tissues, tendons, as well as osteotomy procedures.

Fracture in nanoporous gold: An integrated computational and experimental study

We present simulation/experimental integrated study examining crack propagation in nanoporous gold. We utilized a simulation technique that combines continuum fracture mechanics with molecular dynamics. We applied this to a large atomistic digital sample of nanoporous gold to implement mode-1 crack propagation. Crack propagation tests were also conducted on an experimental sample, prepared via chemical dealloying and observed via in-situ TEM microscopy. We observed cracks in both samples propagating by the same mechanisms of sequential individual ligament failure. A series of nanowire computational deformation tests were also conducted to understand individual ligament behavior, and how this influences the overall sample fracture. This iterative direct experiment/simulation comparison provides new insight into the failure response of nanoporous gold.

Bioresorbable Stent in Anterior Cruciate Ligament Reconstruction.

The exact causes of failure of anterior cruciate ligament (ACL) reconstruction are still unknown. A key to successful ACL reconstruction is the prevention of bone tunnel enlargement (BTE). In this study, a new strategy to improve the outcome of ACL reconstruction was analyzed using a bioresorbable polylactide (PLA) stent as a catalyst for the healing process. The study included 24 sheep with 12 months of age. The animals were randomized to the PLA group (n = 16) and control group (n = 8), subjected to the ACL reconstruction with and without the implantation of the PLA tube, respectively. The sheep were sacrificed 6 or 12 weeks post-procedure, and their knee joints were evaluated by X-ray microcomputed tomography with a 50 μm resolution. While the analysis of tibial and femoral tunnel diameters and volumes demonstrated the presence of BTE in both groups, the enlargement was less evident in the PLA group. Also, the microstructural parameters of the bone adjacent to the tunnels tended to be better in the PLA group. This suggested that the implantation of a bioresorbable PLA tube might facilitate osteointegration of the tendon graft after the ACL reconstruction. The beneficial effects of the stent were likely associated with osteogenic and osteoconductive properties of polylactide.

How variability in interfacial properties results in tougher bonded composite joints by triggering bridging

Toughening strategies are needed to design high performance secondary bonded joints. Although adhesively bonded joints present a promising solution for cost-saving assembly, they are however among the most vulnerable parts in composite structures. Due to the inherent heterogeneity of composite substrates and the infeasibility of ideal surface pretreatments, the bonding properties of composite joints feature a spatial variability that can result in a wide variety of debonding phenomenology, such as crack tip transfer, crack bifurcation or ligament bridging. In the present work, we apply a cohesive zone model with spatially stochastic interfacial properties to model the physical behaviors that take place during debonding of an adhesively bonded composite joint. The joint distribution of the two essential bonding properties, namely, the critical separating stress σm and the strain energy release rate Gc, follows a bivariate lognormal probability distribution. The proposed model captures the mechanisms of crack-tip transfer and the failure of bridging adhesive ligaments between the composite adherends, as well as the associated toughening of joints. We find that the extrinsic dissipation attributed to extra debonding areas and plastic-damage mechanisms of ligaments may be one of the primary causes for the thickness effect of bondline on the fracture toughness, commonly observed for adhesively bonded joints. Through a parametric study, we discuss the effect of variability in interfacial properties on the enhancement of toughness of bonded composite joints. The outcomes of this work may provide insights into the fundamental failure mechanisms of secondary bonded composite joints.

PO 18239 - Malerba Z-type osteotomy for the treatment of adult acquired flatfoot deformity

Introduction: Adult acquired flat foot deformity (AAFD) is a condition characterized by tendon and ligament failure that leads to progressive midfoot collapse and to hindfoot valgus. Calcaneal osteotomies are among the oldest and most conventional procedures for the treatment of angular limb deformities; they aim to reestablish the alignment and the line of action vector of the triceps surae muscle. Various disadvantages of classic osteotomies have been established in recent years, such as fixation loss, insufficient correction and reduced tarsal tunnel volume. Malerba Z-type osteotomy aims to resolve possible complications resulting from the usual incisions, to enhance the procedure and to allow multiplane corrections. Objective: To describe the functional and radiographic outcomes of Malerba Z-type osteotomy in patients with AAFD subjected to reconstructive surgery. Methods: Ten patients diagnosed with AAFD, with a mean age of 45 years (35-55), were operated on from January 2017 to January 2018. All patients underwent weight-bearing radiographs and alignment measurements and functional assessment using the pain visual analog scale (VAS) and the American Orthopedic Foot and Ankle Society (AOFAS) scale preoperatively and at the final evaluation at a mean of 12 months (6-18 months) after surgery. Results: The 10 patients showed positive progression after the surgery, reporting no major complications. Only one case of superficial dehiscence and one case of transient sural nerve neuropraxia (in different patients) were observed. On average, the AOFAS score increased by 50 points on average (25.7 to 76.6), and the VAS score decreased by 4 points (8.3 to 3.4). The mean calcaneal pitch increased from 5.5° to 15.2°. Nine patients transitioned from valgus malalignment (hindfoot angle greater than 10°) to the physiological (5 to 10° valgus) range. Conclusion: Ankle-foot realignment is an essential condition for surgical success in AAFD; it promotes a soft-tissue healing environment while maintaining an adequate muscle line of action. Malerba Z-type osteotomy was found to be a safe technique with high potential for deformity correction, leading to functional and radiographic improvement in patients who undergo this surgery.

Mechanical characterisation of the lateral collateral ligament complex of the ankle at realistic sprain-like strain rates

BackgroundSynthetic interventions continue to evolve with the progression made in materials science, surgical technologies and surgical methods. To facilitate the evolution of synthetic devices for lateral ankle repair a better understanding of the mechanical properties and failure mechanisms of the lateral collateral ligament (LCL) complex is required. This study aimed to improve understanding of the mechanical properties and failure modes of the LCL complex at strain rates representative of sprain. MethodThe LCLs were dissected from six human cadavers to produce individual bone-ligament-bone specimens. A mechanical testing device uni-axially loaded the ligaments in tension. Initially, preconditioning between 2 N and a load value corresponding to 3.5% strain was conducted for 15 cycles, before extension to failure at strain rate of 100%.s−1. The results were stratified by age, weight and body mass index (BMI) to explore potential correlations with ligament ultimate failure load or ligament stiffness. ResultsThe mean ultimate failure loads and the 95% confidence intervals for the ATFL, calcaneofibular (CFL) and posterior talofibular (PTFL) ligaments were 263.6 ± 164.3 N, 367.8 ± 79.8 N and 351.4 ± 110.8 N, respectively. A strong positive Pearson correlation was found between BMI and ultimate failure load of the CFL (r = 0.919; P = .01). A non-significant relationship was found between the mechanical properties and both age and weight. The ATFL avulsed from the fibula four times, the CFL avulsed from the fibula twice, the PTFL avulsed from the talus twice and all remaining failures were mid-substance. ConclusionThe results identify the forces required to induce failure of the individual ligaments of the LCL complex and the related failure modes of individual ligaments. A correlation may exist between BMI and the ultimate failure load of the CFL and PTFL, although a greater sample size is required for confirmation.

ACL Reconstruction In High School and College-aged Athletes: Does Autograft Choice Affect Recurrent ACL Revision Rates?

Objectives: Physicians’ and patients’ decision-making process between bone-patellar tendon-bone (BTB) versus hamstring autografts for ACL reconstruction (ACLR) may be influenced by a patient’s gender, laxity level, sport played, and/or competition level in the young, active athlete. The purpose of this study was to determine the incidence of subsequent ligament disruption for high school and college-aged athletes between autograft BTB versus hamstring grafts for ACLRs. Our hypothesis is there would be no recurrent ligament failure differences between autograft types at 6-year follow-up. Methods: Our inclusion criteria were patients aged 14-22 who were injured in sport (basketball, football, soccer, other), had a contralateral normal knee, and were due to have a unilateral primary ACLR with either a BTB or hamstring autograft. All patients were prospectively followed at two and six years and contacted by phone and/or email to determine whether any subsequent surgery had occurred to either knee since their initial ACLR. If so, operative reports were obtained, whenever possible, in order to document pathology and treatment. Multivariable regression modeling controlled for age, gender, ethnicity/race, body mass index, sport and competition level, activity level, knee laxity, and graft type. The six-year outcomes of interest were the incidence of subsequent ACL reconstruction to either knee. Results: Eight hundred thirty-nine (839) patients were eligible, of which 770 (92%) had 6-year follow-up for subsequent surgery outcomes. The median age was 17, with 48% females, and the distribution of BTB to hamstring was 492 (64%) and 278 (36%) respectively. Thirty-three percent (33%) of the cohort was classified as having “high grade” knee laxity preoperatively. The overall ACL revision rate was 9.2% in the ipsilateral knee, 11.2% in the contralateral normal ACL, and 19.7% had one or the other within 6 years of the index ACLR surgery. High-grade laxity (OR: 2.4; 95% CI: 1.4, 3.9; p=0.001), autograft type (OR: 2.1; 95% CI: 1.3, 3.5; p=0.004), and age (OR: 0.8; 95% CI: 0.7, 0.96; p=0.009) were the 3 most influential predictors of a recurrent ACL graft revision on the ipsilateral knee, respectively, whereas the sport of the index injury (OR: 0.3; 95% CI: 0.2, 0.7; p=0.002) was the most influential predictor of a subsequent primary ACL reconstruction on the contralateral knee. The odds of a recurrent ACL graft revision on the ipsilateral knee for patients receiving a hamstring autograft were 2.1 times the odds of a patient receiving a BTB autograft (95% CI: 1.3, 3.5). For low-risk patients (5% incidence of graft failure), a hamstring graft can increase the risk of recurrent ACL graft revision by 5 percentage points, from 5% to 10%. For high-risk patients (35% incidence of graft failure), a hamstring graft can increase the risk of recurrent ACL graft revision by 15 percentage points, from 35% to ˜ 50%. An individual prediction risk calculator for a subsequent ACL graft revision can be determined by the nomogram in Figure 1. Conclusion: There is a high rate of subsequent ACL tears in both the ipsilateral and contralateral knees in this young athletic cohort, with evidence suggesting that incidence of ACL graft revisions at 6 years following index surgery is significantly higher in hamstring autograft compared to BTB autograft. [Figure: see text]

Development of a 3-y-old Pediatric Cervical Spine Finite Element Model

A 3-year-old pediatric cervical spine finite element (FE) model with detailed anatomical and material properties was developed and validated against cadaver tests under both quasi-static loadings. First, bone geometry was reconstructed based on high-resolution computed tomography (CT) scans, and elastic-plastic material was defined to simulate the cortical and cancellous bones. To simulate various ligament tears during dynamic tensile, ligament failure was defined using force versus displacement curves, which had a sigmoidal shape governed by three control points. To better represent the complicated structure of the disc, nucleus pulposus, annulus fibrosus substrate and four pairs of reinforced fiber lamina, intervertebral discs were defined using composite materials combined with viscoelastic material, hill foam material and four pairs of reinforced fiber lamina, respectively. This FE model could be utilized in prediction of cervical spine fracture, ligament and disc tear underlying pediatric cervical injuries.

Experimental investigation on the failure mechanism of a rock landslide controlled by a steep-gentle discontinuity pair

A type of rock landslide is very common in practical engineering, whose stability is mainly controlled by the rock bridge between the steep tensile crack at the crest and the low-inclination weak discontinuities at the toe (namely, ligament is the term for the locking section in the slope). To obtain a deeper understanding into the failure process of this kind of landslide, twenty-four physical slope models containing a steep-gentle discontinuity pair (a steep crack in the upper part and a low-inclination discontinuity in the lower part) were tested by applying vertical loads at the crests. The results indicate that the inclination angle of the ligament (θ) has great influence on the failure and stability of this type of rock slope. With the change of θ, three failure patterns (five subtypes) concerning the tested slopes can be observed, i.e., tensile failure of the ligament (Type 1), tension-shear failure of the ligament (Type 2) and two-stage failure of the main body (Type 3). The failure process of each failure mode presents five stages in terms of crack development, vertical load, horizontal/vertical displacements and strains in the ligaments. The specific range of the ligament angle between different failure patterns is summarized. The discussion on the failure resistances and ductility of different failure patterns, and the guiding significances of the experimental findings to the stability evaluation and the reinforcement were conducted.

Differentiation of anteroposterior pelvic compression type I and II injuries and severity evaluation

Objective To investigate the reliability of using the pubic symphysis diastasis of 25 mm and anterior separation distance of sacroiliac joint to differentiate anteroposterior compression (APC) type I and II injuries as well as assess the injury severity. Methods A total of 11 (seven males and four females) fresh cadaver specimens with 22 hemipelvis were collected. The pelvic APC injury test models including fixed hemipelvis (restricted group) and unfixed hemipelvis (non-restricted group) were established, with 11 hemipelvis in each group according to the random number table method. Meanwhile the specimens were divided into male group (14 hemipelvis) and female group (eight hemipelvis), simulating APC type injury external rotation hemipelvis. The public symophysis interval and anterior interval of sacroiliac joint of the original pelvis, the pubic symphysis diastasis and anterior diastasis of sacroiliac joint after anterior tibiofibular ligament failure, as well as the affected pelvis ligament and sacral ligament injury were recorded and compared between the restricted and non-restricted groups, male and female groups. Results There were no significant differences in the public symphysis interval of the original pelvis and anterior interval of sacroiliac joint between the restricted group and the non-restricted group (P>0.05). The pubic symphysis interval of the original pelvis was [(5.13±0.61)mm] in male group and (4.03±0.84)mm] in female group (P 0.05). In terms of anterior interval of sacroiliac joint, there was significant difference between male and female groups (P 0.05). In the restricted group, sacrotuberous ligament injuries were found in four patients, and sacrospinous ligament injuries in five, whhile there were no obvious sacrospinous ligament and sacrotuberous ligament injuries in non-restricted group. There were 10 specimens with the pubic symphysis diastasis ≥23.36 mm and 10 specimens with the diastasis distance of anterior sacroiliac joint ≥9.82 mm (46%), and there were 15 specimens with at least the pubic symphysis interval ≥23.36 mm or the anterior interval of sacroiliac joint ≥9.82 mm (68%). Conclusions The public symphysis interval ≥ 23.36 mm or anterior interval of sacroiliac joint ≥ 9.82 mm can distinguish anteroposterior compression I from II injuries, and the combination of the two criteria can be beneficial to assessment of pelvic injury severity. Key words: Pelvis; Ligaments; Injury classification

Obstetrical and Non-Obstetrical Factors toward Uterine Prolapse Occurrence in Ulin General Hospital Banjarmasin on Januari – December 2017

Abstract: Uterine prolapse is a gynecological disease in women that emerge patients physically and psychologically. Uterine prolapse is defined as an uterus herniation inside or outside vagina as the result of the ligament and fascia failure that retain the uterus in its actual place. This research was to identify obstetrical and non-obstetrical factors in uterine prolapses occurrence in Ulin General Hospital Banjarmasin on period January until December 2017 using case control approach. The total sample was 80 medical record samples, which divided into 40 medical record samples of patient with uterine prolapse and 40 medical record samples of patient without the occurrence of uterine prolapse. The results using chi square analysis obtained non-obstetrical factors: age &gt;60 years old (OR 6.67: 95%CI 2.44-18.21), BMI &gt; 30 (OR 3.10: 95%CI 1.24-7.71), menopause (OR 21.00: 95%CI 6.11-72.18); and non-obstetrical factors: parity &gt;4 / multiparity (OR 13.78: 95%CI 4.71-40.28), macrosomia (OR 7.15: 95%CI 2.65-19.34), vaginal delivery (OR 28.78: 95%CI 7.41-111.79). The results of logistic regression obtained non-obstetrical factors: age &gt; 60th (Exp B 4.21 and sig. 0.004), menopause (Exp B 1.12 and sig. 0.001), and multiparity (Exp B 2.35 and sig. 0.016). The results of this analysis obtained that obstetrical and non-obstetrical factors were related to uterine prolapse occurrence, and the dominant factor was age &gt; 60 years old, so it could be concluded that there was significant factor between obstetrical and non-obstetrical factors on uterine prolapse occurrence in Ulin General Hospital Banjarmasin. Keywords: uterine prolapse, obstetrical factor, non-obstetrical factor