Insertion Area Research Articles

Multimaterial and multiscale scaffold for engineering enthesis organ.

Tendon and ligament injuries are relevant clinical problems in modern society, and the current medical approaches do not guarantee complete recovery of the physiological functionalities. Moreover, they present a non-negligible failure rate after surgery. Failures often occur at the enthesis, which is the area of tendons and ligaments insertion to bones. This area is highly anisotropic and composed of four distinct zones: tendon or ligament, non-mineralized fibrocartilage, mineralized fibrocartilage, and bone. The organization of these regions provides a gradient in mechanical properties, biochemical composition, cellular phenotype, and extracellular matrix organization. Tissue engineering represents an alternative to traditional medical approaches. This work presents a novel biofabrication approach for engineering the enthesis. Gradient-based scaffolds were fabricated by exploiting the combination of electrospinning and three-dimensional (3D) bioprinting technologies. Studies were conducted to evaluate scaffold biocompatibility by seeding bone marrow-derived mesenchymal stem cells (BM-MSCs). Then, the scaffold's ability to promote cellular adhesion, growth, proliferation, and differentiation in both tenogenic and osteogenic phenotypes was evaluated. Fabricated scaffolds were also morphologically and mechanically characterized, showing optimal properties comparable to literature data. The versatility and potentiality of this novel biofabrication approach were demonstrated by fabricating clinical-size 3D enthesis scaffolds. The mechanical characterization highlighted their behavior during a tensile test was comparable to tendons and ligaments in vivo.

Triceps tendon avulsion in a cat

AbstractA 1‐year‐8‐month‐old, male, neutered Maine Coon presented to a referral veterinary hospital for a weight‐bearing lameness of the left thoracic limb that occurred 4 weeks prior to presentation. A transverse groove, proximal to the olecranon, was palpated in the area of the normal insertion of the triceps tendon. Computed tomography of the left thoracic limb revealed a complete avulsion of the long and lateral heads of the triceps brachii from the olecranon. Multiple, small, mineralised fragments were present within the distal portion of the retracted tendons of insertion, and there were corresponding osseous defects within the olecranon. A modified three‐loop pulley suture technique was utilised to fix the triceps tendon to the olecranon. The joint was then immobilised with a trans‐articular external skeletal fixator. Three months after surgery, the owners reported no abnormalities or concerns regarding the cat's elbow or ambulation.

Global Compressive Loading from an Ultra-Thin PEEK Button Augment Enhances Fibrocartilage Regeneration of Rotator Cuff Enthesis.

A PEEK button is developed to improve the tendon-to-bone compression area. In total, 18 goats were divided into 12-week, 4-week, and 0-week groups. All underwent bilateral detachment of the infraspinatus tendon. In the 12-week group, 6 were fixed with a 0.8-1 mm-thick PEEK augment (A-12, Augmented), and 6 were fixed with the double-row technique (DR-12). Overall, 6 infraspinatus were fixed with PEEK augment (A-4) and without PEEK augment (DR-4) in the 4-week group. The same condition was performed in the 0-week groups (A-0 and DR-0). Mechanical testing, immunohistochemistry assessment, cell responses, tissue alternation, surgical impact, remodeling, and the expression of type I, II, and III collagen of the native tendon-to-bone insertion and new footprint areas were evaluated. The average maximum load in the A-12 group (393.75 (84.40) N) was significantly larger than in the TOE-12 group (229.17 (43.94) N) (p < 0.001). Cell responses and tissue alternations in the 4-week group were slight. The new footprint area of the A-4 group had better fibrocartilage maturation and more type III collagen expression than in DR-4 group. This result proved the novel device is safe and provides superior load-displacement to the double-row technique. There is a trend toward better fibrocartilage maturation and more collagen III secretions in the PEEK augmentation group.

PERCUTANEOUS ENDOSCOPIC GASTROSTOMY RESULTS IN A SECONDARY STATE HOSPITAL

Introduction: The aim of this study was to determine the indications of Percutaneous endoscopic gastrostomy (PEG) patients treated in a secondary state Burdur hospital over a period of three years, the unit where the patient was hospitalized, survival time with PEG therapy, and the complications observed in these patients. Methods: Patients who underwent PEG in the endoscopy unit of our hospital, between January 2019 and January 2022, were retrospectively evaluated. Age, gender, the unit of inpatient, indications for PEG therapy, complications after PEG, and survival status of the patients were recorded in the form of case reports. Patients with coagulation disorders, hemodynamic instability, peritonitis, sepsis, infection at the insertion area, peritonitis carcinomatosis, a history of total gastrectomy and gastric varices were excluded. Results:The median age of the 120 patients included in the study was 79 (17–100) years, and 66 (55%) of the patients were male. Complications were observed in 14 (11.7%) patients, all of which were minor, including seven (5.8%) PEG site infections, three (2.5%) PEG site leakages, three (2.5%) PEG occlusions, and one (0.9%) PEG removal. It was determined that 73 (60.8%) patients survived at least 30 days; the patients were most frequently referred by the neurology unit, with a rate of 52.7%. The most common indications for PEG insertion were cerebrovascular disease (56.7%) and dementia (29.2%). Conclusion: Maintenance of nutritional requirements via PEG allows for the preservation of mucosal integrity and barrier function, intestinal immune response, and normal flora. It is superior to other enteral feeding methods due to the lower risk of aspiration. In conclusion, our study, which presented the experiences of the PEG insertion and therapy in a secondary state hospital, stated that the complication rates, indications, and referring clinics were found to be consistent with available literature.

Insertion sites of the muscles attached to the clavicle: a cadaveric study of the clavicle

BackgroundClavicle fractures are common injuries, especially in young, active individuals. Operative treatment is recommended for completely displaced clavicle shaft fractures, and plate fixation is stronger than the use of intramedullary nails. Few studies have reported on iatrogenic injuries to the muscle attached to the clavicle during fracture surgery. The aim of this study was to clarify the area of the insertion sites of muscles attached to the clavicle in Japanese cadavers using gross anatomy and three-dimensional (3D) analysis. We also aimed to compare the effects of anterior plate templating and superior plate templating on clavicle shaft fractures using 3D images.MethodsThirty-eight clavicles from Japanese cadavers were analyzed. We removed all clavicles to identify the insertion sites and measured the size of the insertion area of each muscle. Three-dimensional templating was performed on both the superior and anterior plates of the clavicle using data obtained from computed tomography. The areas covered by these plates on the muscles attached to the clavicle were compared. Histological examination was performed on four randomly selected specimens.ResultsThe sternocleidomastoid muscle was attached proximally and superiorly; the trapezius muscle was attached posteriorly and partly superiorly; and the pectoralis major muscle and deltoid muscles were attached anteriorly and partially superiorly. The non-attachment area was located mainly in the posterosuperior part of the clavicle. It was difficult to distinguish the borders of the periosteum and pectoralis major muscles. The anterior plate covered a significantly broader area (mean 6.94 ± 1.36 cm2) of the muscles attached to the clavicle than did the superior plate (mean 4.11 ± 1.52 cm2) (p < 0.0001). On microscopy, these muscles were inserted directly into the periosteum.ConclusionMost of the pectoralis major and deltoid muscles were attached anteriorly. The non-attachment area was located mainly from the superior to posterior part of the clavicle midshaft. Both macroscopically and microscopically, the boundaries between the periosteum and these muscles were difficult to demarcate. The anterior plate covered a significantly broader area of the muscles attached to the clavicle than that by the superior plate.

Shape variation in the limb long bones of modern elephants reveals adaptations to body mass and habitat.

During evolution, several vertebrate lineages have shown trends towards an increase in mass. Such a trend is associated with physiological and musculoskeletal changes necessary to carry and move an increasingly heavy body. Due to their prominent role in the support and movement of the body, limb long bones are highly affected by these shifts in body mass. Elephants are the heaviest living terrestrial mammals, displaying unique features allowing them to withstand their massive weight, such as the columnarity of their limbs, and as such are crucial to understand the evolution towards high body mass in land mammals. In this study, we investigate the shape variation of the six limb long bones among the modern elephants, Elephas maximus and Loxodonta africana, to understand the effect of body mass and habitat on the external anatomy of the bones. To do so, we use three-dimensional geometric morphometrics (GMMs) and qualitative comparisons to describe the shape variation, at both the intraspecific and interspecific levels. Our results reveal that the two species share similar negative ontogenetic allometric patterns (i.e. becoming stouter with increased length) in their humerus and femur, but not in the other bones: the proximal epiphyses of the stylopod bones develop considerably during growth, while the distal epiphyses, which are involved in load distribution in the elbow and knee joints, are already massive in juveniles. We attribute this pattern to a weight-bearing adaptation already present in young specimens. Among adults of the same species, bone robustness increases with body mass, so that heavier specimens display stouter bones allowing for a better mechanical load distribution. While this robustness variation is significant for the humerus only, all the other bones appear to follow the same pattern. This is particularly visible in the ulna and tibia, but less so in the femur, which suggests that the forelimb and hindlimb adapted differently to high body mass support. Robustness analyses, while significant for the humerus only, suggest more robust long bones in Asian elephants than in African savanna elephants. More specifically, GMMs and qualitative comparisons indicate that three bones are clearly distinct when comparing the two species: in E. maximus the humerus, the ulna and the tibia display enlarged areas of muscular insertions for muscles involved in joint and limb stabilization, as well as in limb rotation. These results suggest a higher limb compliance in Asian elephants, associated with a higher dexterity, which could be linked to their habitat and foraging habits.

Enhanced and Stem-Cell-Compatible Effects of Nature-Inspired Antimicrobial Nanotopography and Antimicrobial Peptides to Combat Implant-Associated Infection.

Nature-inspired antimicrobial surfaces and antimicrobial peptides (AMPs) have emerged as promising strategies to combat implant-associated infections. In this study, a bioinspired antimicrobial peptide was functionalized onto a nanospike (NS) surface by physical adsorption with the aim that its gradual release into the local environment would enhance inhibition of bacterial growth. Peptide adsorbed on a control flat surface exhibited different release kinetics compared to the nanotopography, but both surfaces showed excellent antibacterial properties. Functionalization with peptide at micromolar concentrations inhibited Escherichia coli growth on the flat surface, Staphylococcus aureus growth on the NS surface, and Staphylococcus epidermidis growth on both the flat and NS surfaces. Based on these data, we propose an enhanced antibacterial mechanism whereby AMPs can render bacterial cell membranes more susceptible to nanospikes, and the membrane deformation induced by nanospikes can increase the surface area for AMPs membrane insertion. Combined, these effects enhance bactericidal activity. Since functionalized nanostructures are highly biocompatible with stem cells, they make promising candidates for next generation antibacterial implant surfaces.

Three-dimensional finite element analysis of zygomatic implants for rehabilitation of patients with a severely atrophic maxilla

Statement of problemStresses applied to zygomatic implants have been determined to be transferred mainly to the zygomatic bone; however, consensus regarding the stress distribution pattern in the bone surrounding zygomatic implants has not yet been reached. PurposeThe purpose of this 3-dimensional (3D) finite element analysis (FEA) study was to visually compare the stress distribution pattern in 2 different zygomatic implant treatment modalities and evaluate the effect of masseter musculature involvement. Material and methodsA 3D FEA craniofacial model was constructed from the computed tomography (CT) data of a selected patient with a severely atrophic edentulous maxilla. Modeled zygomatic and conventional implants were inserted into the craniofacial model supporting a prosthesis superstructure. Two types of treatment were considered in the study: 2 zygomatic implants placed bilaterally or 2 zygomatic implants placed in conjunction with at least 2 conventional implants at the anterior maxilla. The models were loaded with a vertical force of 150 N, a lateral force of 50 N, and a distributed occlusal force of 300 N applied to the insertion area of the masseter muscle. The stresses on and deformations of the bones and implants were then observed and compared with and without the involvement of the musculature component. ResultsThe stresses were distributed efficiently along the vertical and horizontal facial buttresses, as in the dentate skull; however, a difference in distribution pattern was observed when the models were loaded without applying the muscle component. The maximum deformation of bones surrounding the implants occurred in the abutment connection of the conventional anterior implant in the model with an additional conventional anterior implant. ConclusionsThe FEA revealed the stresses were distributed efficiently along the vertical and horizontal facial buttresses, as in the dentate skull. However, the stresses in both models were concentrated in the zygomatic bone when incorporating the muscle component. Therefore, incorporating muscular force into FEA studies could affect the analysis result.

Correlation between morphological features of the anterior cruciate ligament: A quantitative study using a porcine model.

Knowledge of the morphological features of the anterior cruciate ligament (ACL) is critical for accurate reconstruction of it. This study aimed to explore the quantitative correlations among different morphological features of the ACL, thus to provide useful information for improving anatomical reconstruction techniques and designing artificial ligaments. 19 porcine knees were fixed at full extension using 10% formalin and were dissected to expose the ACL. ACL lengths were measured using a caliper. Mid-substances of the ACL were cut and scanned using X-ray microscopy, and the cross-sectional area (CSA) was measured at the isthmus. Margins of direct and indirect bone insertion sites were distinguished and marked. Measurements were performed on digital photographs to obtain the areas of bone insertions. Statistical analysis using nonlinear regression was used to identify potential correlations among the measurements. The results showed that the CSA at the isthmus was significantly correlated with the total area of the bone insertion sites and the area of tibial insertion. The area of the tibial insertion was significantly correlated with the area of its direct insertion site. In contrast, the area of the femoral insertion was significantly correlated with the area of its indirect insertion site. The area of the indirect tibial insertion showed a weak correlation with the length of ACL, whereas the length of the ACL was not able to predict or be predicted by any other parameters. The CSA at the ACL isthmus is more representative for assessing the size of the ACL. However, ACL length has little correlation with the CSA of the isthmus or bone insertion sites, and thus should be evaluated independently for ACL reconstruction.

External and Skeletal Morphology of Molossus fluminensis Lataste, 1891 (Chiroptera, Molossidae) with Notes on Quadrupedal Locomotion and Habitat Use

Molossus fluminensis is a species of the wide diversified family Molossidae. Representants of this family have evolved under pressures associated to two different behaviors — a high speed and efficient flight and a good quadrupedal ability. The aim of this study is to describe in detail the morphological characters of M. fluminensis, focusing on its skeletal features, and to point out the main characters that could represent functional responses to the evolution of the quadrupedal ability and habitat use in the group. Furthermore, we aim to contribute to the knowledge of a recently revalidated and cryptic species of Molossus, giving a morphometric characterization for the species and notes on sexual dimorphism. Four adult specimens of M. fluminensis, one male and three females, were prepared as skin and skeleton, and five external and 146 linear measurements of the skeleton were taken. The anatomical characters were described following current literature and included the axial and appendicular skeleton. We found that the male presented greater measurements than females in most linear characters, and had a more developed sagittal and lambdoid crests, while the ischiatic arcade was more caudally projected in females. A narrow rib cage, a long, thin sternum, and a cranially oriented ventral process of manubrium make the M. fluminensis body more compact dorsoventrally without compromising the area of insertion of the flight musculature. These appear to be adaptations for roosting in narrow crevices. The expanded sacral vertebrae, the deep gluteal fossa of the ilium, and the presence of well-developed processes on the first caudal vertebra, point to a greater area for muscle origin in this region, while the well-developed trochanters and ridges of the femur and tibia provide surfaces for muscle attachment. Together, these characteristics point to a great range of movement of the limbs and the tail, important factors during quadrupedal locomotion. The results obtained here may shed light on the evolution of quadrupedalism in molossids and other quadrupedal bats.

Topographic localization of the sacroiliac joint and superior gluteal artery branches on the posterolateral ilium.

Latrogenic vascular injuries at the posterior ilium during sacroiliac screw placements are not uncommon. Though intra-operative imaging reduces the risk of such injuries, anatomical localization of the sacral segments using discrete topographical landmarks is not currently available. This descriptive study proposes the use of an anatomical grid system to localize the sacroiliac articulation on the posterolateral ilium. It also investigates the positional variability of the branches of the superior gluteal artery (SGA) within areas defined by the grid. 48 dried adult hip bones were examined to determine the position of the sacral articular surface on the posterolateral surface of the ilium. A novel grid-system was defined and used to map the positions of the articulation of the first two sacral segments on the posterolateral ilium. Superficial and deep branches of the SGA were dissected in donor cadavers and their courses were virtually overlayed on the grid system. The grid system localized the sacral articular surfaces within a defined area on the posterior ilium. Arterial distributions indicated the presence of the superficial branch of SGA more frequently over the screw insertion area (at an intermuscular plane), while the deep branch ran closer to the ilium but antero-inferior to the screw placement areas. This study proposes a new topographical perspective of visualizing SGA branches with respect to the cranial sacral segments. Precise localization of vascular anatomy may help to reduce potential risk of injury during sacroiliac screw placements.

Intraosseous access: a simulation analysis

Introduction: The priority in critical patients is to find a vascular access. The most used access is the peripheral venous access, but when its placement goes wrong or is difficult, the literature recommends implementing intraosseous (IO) access as a valid alternative. The IO access is a rapid, reliable and a relatively safe method. Despite the recommendations, IO access is rarely used when indicated. The objective of this study was to evaluate the critical points of the IO procedure, positioning time, percentage of success at first attempt in simulation and, in according to obtained outcomes, checking of the procedure inclusion within university programs. Material and methods: A sample of 84 people was recruited; among them 44 were students attending the third year of the Degree Course in Nursing of the University of Turin (site of Asti) and 40 nurses from intensive care unit and emergency ward of Cardinal Massaia Hospital of Asti. A short lesson about IO access took place, followed by a practical demonstration. Subsequently, the IO access insertion performance and difficulty perceived were evaluated. Statistical analysis was performed by means of inferential and descriptive bivariate analysis. Results: The average value of the performance “IO access insertion” was 12.2±1.22 (average of the assigned points by the sample). The average difficulty perceived was 1.65±0.42, and mainly found in “selection of the correct point of insertion” with a value of 2.64±0.87, “needle placement” with a medium value of 2.35±1.02 and “medication” with a value of 2.0±0.94. Average execution time of IO access and needle placement were 73.3 and 36.1 seconds, respectively. Finally, the success rate at the first attempt was 72.6%. Discussion: The IO access execution time, for the complete procedure and for the needle placement only, was below the 3 minutes. Among nurses and students, data of the success of the procedure show significant results, but the difference between subgroups is still lower than expected considering the results of the statistical analysis about procedure success, execution time and error percentage. Most critical issues were found in the retrieval of area of insertion, whereas the most difficulty perceived was on reference point selection, correct needle placement and medication. The procedure may become subject of teaching in the University. Conclusion: The study evaluates the possibility of the IO access use, by underlining how is necessary a training about it. The principal reason of ‘non-use’ of this device is the disinformation of healthcare professionals. The results seem to underline the importance of a possible integration of IO access technique in the programs of Degree Nursing Course and post-base course. This may improve nursing in emergency situations and therefore, patient outcomes. When healthcare staff training is possible, periodical refresh is particularly recommended in order to maintain the acquired skills.

Comparison of the morphology of the anterior cruciate ligament and related bony structures between pigs and humans.

Pigs are widely used for clinical research on the anterior cruciate ligament (ACL) because of the similarity of the knee structure to the human knee. But evidence to support the suitability of using porcine samples to guide clinical practices is limited. This study aims to explore the qualitative and quantitative morphological features of the porcine knee and ACL, and to compare these with data on humans reported in literature. Nineteen porcine knees were used for this study. The bone structures were measured on coronal X-ray images. The length of the ACL was measured using a caliper. The ACL bone insertion sites were marked and measured on a digital photograph. The lengths of the long and short axis of the ACL isthmus were measured on the X-ray microscopy reconstructed images. The outcomes were compared with previously reported data on humans using an abstract independent-samples T test. Qualitative observation indicated a similar location, orientation and general morphology of the porcine ACL to human ACLs. The major difference was the location of the ACL tibial insertion with respect to the anterior horn of the lateral meniscus (AHLM). The porcine ACL was split into AM and PL bundles by the AHLM, while the AHLM was adjacent to the anterolateral border of the ACL tibial insertion in human knees. The quantitative comparison showed no significant difference between the human and porcine ACL in terms of the length of the ACL, the width of the femoral condyle and tibial plateau, and the tibial interspinal width. However, the CSA, the lengths of the long and short axis of the ACL isthmus, and the femoral and tibial insertion areas of the porcine ACL were all significantly larger than the reported features in human knees. The location, orientation and basic morphology of the porcine ACL and knee are similar to humans. However, the two-bundle structure is more distinct in a porcine ACL, and the dimensions of the porcine ACL are generally larger. This study may provide useful information to researchers when assessing the feasibility and limitations of using porcine samples for research on the human ACL and knee.

Anatomy of the biceps brachii osseous footprint: study of 100 radii and literature review

Biceps brachii (BB) tendon rupture is frequent in young males and may require surgical repair. Non-anatomic reinsertion leads to loss of strength in supination. The main aim of the present study was to describe the anatomy of the osseous footprint of the distal BB tendon. The dimensions of the footprint of the distal BB insertion were analyzed in 100 dry cadaver radii, using MicroScribe 3D software. Insertion area, assimilated to an ellipse, was calculated from 4 points (medial, lateral, cranial and caudal) determining the two axes of the ellipse. Mean footprint length, width and area were 18 mm (range, 7–24 mm), 9 mm (range, 4–15 mm), and 129 mm2 (range, 46–266 mm²), respectively. Intra- and inter-observer correlation coefficients were satisfactory: κ = 0.75 and κ = 0.7, respectively. The present study reported BB footprint dimensions in 100 radii, providing a basis to guide surgical treatment of distal BB tendon rupture. Non-anatomical restoration of the BB tendon footprint leads to poorer clinical and biomechanical results; precise knowledge of the footprint is necessary for anatomical repair.

The Biomechanical Stability of Bone Staples in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction Depends on the Implant Design

Background: The promising biomechanical stability of bone staples (BSs) in cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction has been revealed by a previous investigation. However, it is currently unknown if the biomechanical stability of cortical fixation of tendon grafts depends on the BS design. Purpose: To assess the biomechanical stability of cortical fixation of tendon grafts in knee surgery using 4 different BS designs. Study Design: Controlled laboratory study. Methods: Cortical fixation of tendon grafts was performed in a porcine knee model at the tibial insertion area of the MCL using 4 different BS designs (n = 40): 8-mm width without spikes (n = 10), 8-mm width with spikes (n = 10), 14-mm width with spikes (n = 10), and 13 mm–wide 4-prong staples with spikes (n = 10). Specimens were mounted in a materials testing machine, and cyclic loading was applied to the tendon graft (500 cycles at 50 and 100 N, respectively), followed by load-to-failure testing. The Kruskal-Wallis test was performed for statistical analysis (P < .05), and the post hoc Dunn test was performed for multiple comparisons. Results: In 4 of 10 specimens with graft fixation using BSs without spikes, slippage of the tendon underneath the BS led to failure of the construct during cyclic loading to 100 N. In the other groups, no fixation failure was observed during cyclic loading. Furthermore, graft fixation using BSs without spikes was found to have significantly more elongation during cyclic loading (8.2 ± 1.9 mm) and a lower ultimate failure load (170 ± 120 N) compared with graft fixation using narrow BSs with spikes (3.4 ± 1.2 mm [P < .0001] and 364 ± 85 N [P < .05], respectively) and graft fixation using broad BSs with spikes (4.5 ± 1.4 mm [P < .05] and 429 ± 67 N [P < .001], respectively). No statistical differences in elongation during cyclic loading or ultimate failure load were found between 4-prong staples with spikes (5.0 ± 1.3 mm and 304 ± 85 N) and narrow or broad staples with spikes. Conclusion: The biomechanical stability of cortical fixation of an MCL graft was comparable between each BS design with spikes (narrow, broad, and 4-prong) in a porcine knee model, whereas BSs without spikes led to failure of the fixation construct during cyclic loading in 4 of 10 specimens and increased elongation and lower ultimate failure loads in the remainder of the group. BSs without spikes may therefore not be recommended for graft fixation. Clinical Relevance: The use of BSs can help to avoid the conflict of converging tunnels in multiligament reconstruction surgery. An implant design with spikes yields significantly higher biomechanical stability than BSs without spikes.

Technique of ACL Reconstruction With Autologous Quadriceps Tendon Bone Graft and Femoral Press Fit Fixation

Background: Recently, there has been an increase in interest in the quadriceps tendon (QT) as an alternative autologous graft option for primary anterior cruciate ligament (ACL) reconstruction. Indication: Anterior cruciate ligament reconstruction in skeletally mature patients (high-risk patients for re-rupture and patients with medial instability). Technique Description: The QT graft is harvested with a 4-cm skin incision over the superior pole of the patella. A double knife and an oscillating saw are used to obtain the QT graft with a bone block from the patella (65 mm x 10 mm graft and 15 mm bone block). Then an arthroscopy is carried out with assessment of the ACL tear and treatment of further intraarticular injuries. ACL reconstruction begins with debridement of the femoral insertion to expose the land marks. The medial portal is used for femoral tunnel drilling with the knee in more than 110° of flexion. A special portal aiming device is introduced via the anteromedial portal and a guide wire is placed in the area of the femoral anteromedial insertion. This guide wire is gradually overdrilled with various drills and dilators of increasing size. The final diameter should be 0.5 mm smaller than the diameter of the bone block of the graft to allow for press-fit fixation. Then, the tibial tunnel is drilled using a tibial drill guide leaving the tibial stump of the original ACL intact. The graft is pulled into the joint through the tibial tunnel until the bone block stops at the femoral tunnel entrance. The bone block is then pushed through the medial portal into the femoral tunnel (press-fit fixation). The tibial fixation is performed with an interference screw and optionally with an extracortical button. Results: Prior studies with 2 years follow-up have shown that the clinical outcomes in primary and revision ACL reconstruction were not significantly different between the use of QT grafts with femoral press-fit fixation and the use of hamstring grafts with femoral suspension fixation. Discussion/Conclusion: Quadriceps tendon bone autograft and femoral press-fit fixation provides an excellent alternative as a graft choice in ACL reconstruction. 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.

Manufacture of Soft-Hard Implants from Electrospun Filaments Embedded in 3D Printed Structures.

Rotator cuff tendon tears are common injuries of the musculoskeletal system that often require surgical repair. However, re-tearing following repair is a significant clinical problem, with a failure rate of up to 40%, notably at the transition from bone to tendon. The development of biphasic materials consisting of soft and hard components, which can mimic this interface, is therefore promising. Here, a simple manufacturing approach is proposed that combines electrospun filaments and 3D printing to achieve scaffolds made of a soft polydioxanone cuff embedded in a porous polycaprolactone block. The insertion area of the cuff is based on the supraspinatus tendon footprint and the size of the cuff is scaled up from 9 to 270 electrospun filaments to reach a clinically relevant strength of 227N on average. The biological evaluation shows that the biphasic scaffold components are noncytotoxic, and that tendon and bone cells can be grown on the cuff and block, respectively. Overall, these results indicate that combining electrospinning and 3D printing is a feasible and promising approach to create soft-to-hard biphasic scaffolds that can improve the outcomes of rotator cuff repair.

A case of titanium-coated pacemaker allergy in a 14-year-old patient

The low informative value of the allergy testing to titanium makes it difficult to diagnose allergy to this component. The present paper describes a case report of an allergy to a titanium-coated pacemaker implanted into a 14-year-old patient. This is the first time eosinophil cationic protein and tryptase to be detected at the inflammation site while making diagnosis of allergy to titanium-coated pacemaker. The reimplantation of a gold-coated pacemaker prevents recurrence of inflammatory changes in the area of pacemaker insertion and infectious complications.

On-Bone Fixation of Free Gingival Graft Induces the Expression of Osteogenic Differentiation Markers in the Mandible of Miniature Pigs.

To study the distribution of markers of mesenchymal stem cells (clusters of differentiation-29 and -44), osteoblasts (osteocalcin), and transforming growth factor-β1 in the mandibular tissue of miniature pigs after on-bone fixation of a free gingival graft. Six outbred male miniature pigs 2 years of age were used in the study. In the external surface of the mandible, the periosteum was excised from all over the free gingival graft fixation area. A free gingival graft was placed on the wound and fixed. In control animals, instead of free gingival graft, a piece of mucoderm (porcine accellular dermal matrix, Botiss Biomaterials) was placed on the wound and fixed. Three months after the surgery, a portion of bone tissue was sampled from the free gingival graft insertion area. The samples were immunohistochemically stained using antibodies against osteoblast and mesenchymal stem cell markers. Three months after surgery, high expression levels of the aforementioned markers were detected in the contact zone between the graft and alveolar bone. Clusters of differentiation-29- and -44-immunopositive cells predominated at the border of the new bone tissue and gingival lamina propria as well as in Haversian canals. Osteocalcin-positive cells were observed mainly in the layer of outer circumferential lamellae, on the surface of concentric lamellae of young osteons forming Haversian canals, and in the Haversian canals in the immediate vicinity of the graft. The bulk of transforming growth factor-β1-expressing cells occurred in the connective tissue Volkmann and Haversian canals and the adventitious and inner vascular membranes. On-bone free gingival graft fixation results in remodeling of the alveolar bone and is accompanied by a change in the immunoreactivity against factors controlling osteogenic differentiation. Clusters of differentiation-29 and -44 expression in mandibular bone tissues suggest that free gingival graft placement results in activation of mesenchymal stem cells and their transforming growth factor-β1-mediated differentiation into osteocalcin-containing osteoblasts.

A new genus of kangaroo (Marsupialia, Macropodidae) from the late Pleistocene of Papua New Guinea

ABSTRACT The extinct macropodine kangaroo, Protemnodon nombe, was first described in 1983 on the basis of two partial dentaries from a late Pleistocene deposit in Nombe Rockshelter, Papua New Guinea. As part of a review of Protemnodon, we noted that P. nombe differed from other members of the genus in several ways that pointed to a position outside of that genus and indeed all other known macropodine genera. The taxon possesses a unique combination of attributes of the dentary and lower dentition, including lower molars with a slight postmetacristid, a small postprotocristid and a gently S-shaped protolophid crest. The proportions of masticatory muscle insertion areas, including a broad masseteric canal for the deep masseter, resemble those of sthenurines, suggesting adaptation to tougher browsed vegetation than other New Guinean macropodines. A parsimony analysis suggests a divergence near the base of the Macropodinae, potentially in the early late Miocene. LSID of publication: urn:lsid:zoobank.org:pub:1458D336-3180-41FE-9DF5-DFAED7971807