A Morel-Lavallee lesion (MLL) is a benign cystic lesion that occurs due to injury to the soft-tissue envelope's perforating vascular and lymphatic systems, resulting in a distinctive hemolymphatic fluid accumulation between the tissue layers. The MLL has the potential to make a significant impact on the treatment of orthopaedic injuries.

A 79-year-old male patient community ambulatory with assisting aid (cane) known case of Diabetes mellitus, hypertension, bronchial asthma and ischemic heart disease. He was brought to the Emergency, complaining of right hip discomfort and burning sensation for the last 5 days with no history of recent trauma at all. Patient had history of right trochanteric femur fracture 3 years ago, treated with DHS in a privet service. Clinical and Radiological assessment showed that the patient mostly has acute MLL due to lag screw cut out. We offered the patient the surgical intervention, but he refused despite explaining the risks of complications if not treated and preferred to receive the conservative treatment. Compression therapy management explained to him including biker's shorts (instructed to be worn full-time a day) and regular follow up in clinic. Symptom's improvement was reported by the patient in the subsequent visits.

In the polytrauma patient, a delayed diagnosis of these lesions is conceivable due to the presence of more visible injuries. It's located over the greater trochanter more commonly, but sometimes in other areas such as the lower lumbar region, the thigh, or the calf. Incorrect or delayed diagnosis and care can have unfavorable outcomes such as infection, pseudocyst development, and cosmetologically deformity. Magnetic resonance imaging (MRI) and ultrasound will aid in MLL diagnosis. However, the effectiveness of MLL therapy remains debatable.

We strongly believe that the MLL caused due to tangential shear forces applied to the soft tissue leads to accumulation of the blood and/or lymph between the subcutaneous and overlying fascia and it often misdiagnosed due to other distracting injuries. Nontheless, in our case we reported MLL occur due to internal pressure on the fascia caused by cut out of DHS lag screw.

To quantify bone-nail fit in response to varying nail placements by entry point translation in straight antegrade humeral nailing using three-dimensional (3D) computational analysis

CT scans of ten cadaveric humeri were processed in 3D Slicer to obtain 3D models of the cortical and cancellous bone. The bone was divided into individual slices each consisting of 2% humeral length (L) with the centroid of each slice determined. To represent straight antegrade humeral nail, a rod consisting of two cylinders with diameters of 9.5mm and 8.5mm and length of 0.22L mm and 0.44L mm respectively joined at one end was modelled. The humeral head apex (surgical entry point) was translated by 1mm in both anterior-posterior and medio-lateral directions to generate eight entry points. Total nail protrusion surface area, maximum nail protrusion distance into cortical shell and top, middle, bottom deviation between nail and intramedullary cavity centre were investigated. Statistical analysis between the apex and translated entry points was conducted using paired t-test.

A posterior-lateral translation was considered as the optimal entry point with minimum protrusion in comparison to the anterior-medial translation experiencing twice the level of protrusion. Statistically significant differences in cortical protrusion were found in anterior-medial and posterior-lateral directions producing increased and decreased level of protrusion respectively compared to the apex. The bottom anterior-posterior deviation distance appeared to be a key predictor of cortical breach with the distal nail being more susceptible. Furthermore, nails with anterior translation generated higher anterior-posterior deviation (>4mm) compared to posterior translation (<3mm).

Aside from slight posterolateral translation of the entry point from the apex, inclusion of a distal posterior-lateral bend into current straight nail design could improve nail fitting within the curved humeral bone, potentially improving distal working length within the flat and narrow medullary canal of the distal humeral shaft.

Back pain is a leading cause of disability worldwide and it is primarily considered to be triggered by intervertebral disc (IVD) degeneration (IVDD). Current treatments may improve pain and mobility, but carry high costs and fail to address IVD repair or regeneration. As no effective therapeutic approach has been proposed to restore inflamed and degenerated IVDs, there is the urgent need to clarify the key pathomechanism of IVDD, the involvement of inflammation, particularly complement activation in matrix catabolism, and how to target them towards tissue repair/regeneration. Mesenchymal stem cell (MSC)-based therapies have become the focus of several regenerative IVD studies. Although patients in clinical trials reported less pain after cell therapy, the long-term success of cell engraftment is unclear due to the hostile IVD environment. The mechanism-of-action of MSCs is mostly dependent on the secreted soluble factors. Moreover, priming of MSC with interleukin (IL)-1β modulates the secretome content, improving its anti-inflammatory and regenerative effect on IVDD organ culture models. MSC-derived extracellular vesicles (EVs) have also been shown to modulate human IVD cells towards a healthy IVD phenotype in vitro. However, the mechanisms involved in the effect of secretome and EVs, particularly with regard to immunomodulation and matrix metabolism, are not fully understood. Our work investigates the effects of secretome and EVs secreted by IL-1β-primed MSCs to impair IVD matrix degradation and/or improve matrix formation in IVDD.

Mechanical loading is important to maintain the homeostasis of the intervertebral disc (IVD) under physiological conditions but can also accelerate cell death and tissue breakdown in a degenerative state. Bioreactor loaded whole organ cultures are instrumental for investigating the effects of the mechanical environment on the IVD integrity and for preclinical testing of new therapies under simulated physiological conditions. Thereby the loading parameters that determine the beneficial or detrimental reactions largely depend on the IVD model and its preparation. Within this symposium we are discussing the use of bovine caudal IVD culture models to reproduce tissue inflammation or matrix degradation with or without bioreactor controlled mechanical loading. Furthermore, the outcome parameters that define the degenerative state of the whole IVD model will be outlined. Besides the disc height, matrix integrity, cell viability and phenotype expression, the tissue secretome can provide indications about potential interactions of the IVD with other cell types such as neurons. Finally, a novel multiaxial bioreactor setup capable of mimicking the six degrees-of-freedom loading environment of IVDs will be introduced that further advances the relevance of preclinical ex-vivo testing.

Worldwide, tendon disorders are one of the main causes of disability that decrease the quality of life of individuals and represent a substantial economic burden on society. Currently, the main therapies used for tendon injuries are not able to restore tendon functionality, and due to tendons' hypovascular and hypocellular nature, they present a reduced healing capacity, which also limits the success of the available therapies. In order to discover new therapies, extracellular vesicles (EVs), key players in cell-cell communication, have been widely explored for tissue engineering and regenerative medicine applications. Thus, the aim of this study is to assess the role of EVs derived from platelets in stem cell tenogenic commitment using a bioengineered tendon in vitro model for potential use as tendon therapeutic agents. Biomimetic platelet-derived EVs were produced by freeze-thaw cycles of platelets and isolation at different centrifugation speed. To recreate the architecture of tendons, a 3D system consisting of electrospun anisotropic nanofiber scaffolds coated with collagen encapsulating human adipose stem cells (hASCs) and different types of platelet-derived EVs, were produced. Then, the influence of the tendon-mimetic constructs and the distinct EVs populations in the hASCs tenogenic differentiation were assessed over culture time. We observed that the hASCs on the nanofibrous tendon scaffolds, show high cytoskeleton anisotropic organization that is characteristic of tenocytes. Moreover, acting as biological cues, platelet-derived EVs boosted hASCs tenogenic commitment, supported by the increased gene expression of tendon-related markers (SCX and TNMD). Additionally, EVs enhanced the deposition of tendon like extracellular matrix (ECM), as evidenced by the increased gene expression of ECM-related markers such as COL1, COL3, DCN, TNC, and MMP-3, which are fundamental for ECM synthesis and degradation balance. Moreover, EVs induced lower collagen matrix contraction on hASCs, which has been related with lower myofibroblast differentiation. Overall, the results revealed that EVs are capable of modulating stem cells' behavior boosting their tenogenic commitment, through the increased expression of healthy tendon cell markers, potentiating ECM deposition and decreasing cell contractility. Therefore, platelet EVs are a promising biochemical tool, worthy to be further explored, as paracrine signaling that might potentiate tendon repair and regeneration.

Recent researches indicate that both M1 and M2 macrophages play vital roles in tissue repair and foreign body reaction processes. In this study, we investigated the dynamics of M1 macrophages in the induced membrane using a mouse femur critical-sized bone defect model.

The Masquelet method (M) and control (C) groups were established using C57BL/6J male mice (n=24). A 3mm-bone defect was created in the right femoral diaphysis followed by a Kirschner wire fixation, and a cement spacer was inserted into the defect in group M. In group C, the bone defect was left uninserted. Tissues around the defect were harvested at 1, 2, 4, and 6 weeks after surgery (n=3 in each group at each time point). Following Hematoxylin and eosin (HE) staining, immunohistochemical staining (IHC) was used to evaluate the CD68 expression as a marker of M1 macrophage. Iron staining was performed additionally to distinguish them from hemosiderin-phagocytosed macrophages.

In group M, HE staining revealed a hematoma-like structure, and CD68-positive cells were observed between the spacer and fibroblast layer at 1 week. The number of CD68-positive cells decreased at 2 weeks, while they were observed around the new bone at 4 and 6 weeks. In group C, fibroblast infiltration and fewer CD68-positive cells were observed in the bone defect without hematoma-like structure until 2 weeks, and no CD68-positive cells were observed at 4 and 6 weeks. Iron staining showed hemosiderin deposition in the surrounding area of the new bone in both groups at 4 and 6 weeks. The location of hemosiderin deposition was different from that of macrophage aggregation.

This study suggests that M1 macrophage aggregation is involved in the formation of induced membranes and osteogenesis and may be facilitated by the presence of spacers.

The aim of the ongoing projects was to demonstrate the efficacy of autologous bone marrow derived stem cells (MSC) combined with biomaterial to induced new bone formation in a randomized multicenter controlled clinical trial.

Patients with a need for bone reconstruction of residual edentulous ridges in both the mandible and maxilla due to bone defects with a vertical loss of alveolar bone volume and/or knife edge ridges (≤ than 4,5 mm) unable to provide adequate primary stabilization for dental implants were included in the clinical study. Autologous bone marrow MSC were expanded, loaded on BCP and used to augment the alveolar ridges. After five months bone biopsies were harvested at the implant position site and implants were installed in the regenerated bone. The implants were loaded after 8–12 weeks. Safety, efficacy, quality of life and success/survival were assessed. Five clinical centers, 4 different countries participated. Bone grafts harvested from the ramus of the mandibles were used as control in the projects.

In cartilage tissue engineering (TE),new solutions are needed to effectively drive chondrogenic differentiation of mesenchymal stromal cells in both normal and inflammatory milieu. Ultrasound waves represent an interesting tool to facilitate chondrogenesis. In particular, low intensity pulsed ultrasound (LIPUS)has been shown to regulate the differentiation of adipose mesenchymal stromal cells. Hydrogels are promising biomaterials capable of encapsulating MSCs by providing an instructive biomimetic environment, graphene oxide (GO) has emerged as a promising nanomaterial for cartilage TE due to its chondroinductive properties when embedded in polymeric formulations, and piezoelectric nanomaterials, such as barium titanate nanoparticles (BTNPs),can be exploited as nanoscale transducers capable of inducing cell growth/differentiation. The aim of this study was to investigate the effect of dose-controlled LIPUS in counteracting inflammation and positively committing chondrogenesis of ASCs embedded in a 3D piezoelectric hydrogel.

ASCs at 2*10⁶ cells/mL were embedded in a 3D VitroGel RGD^® hydrogel without nanoparticles (Control) or doped with 25 µg/ml of GO nanoflakes and 50 µg/ml BTNPs.The hydrogels were exposed to basal or inflammatory milieu (+IL1β 10ng/ml)and then to LIPUS stimulation every 2 days for 10 days of culture. Hydrogels were chondrogenic differentiated and analyzed after 2,10 and 28 days. At each time point cell viability, cytotoxicity, gene expression and immunohistochemistry (COL2, aggrecan, SOX9, COL1)and inflammatory cytokines were evaluated.

Ultrasound stimulation significantly induced chondrogenic differentiation of ASCs loaded into 3D piezoelectric hydrogels under basal conditions: COL2, aggrecan and SOX9 were significantly overexpressed, while the fibrotic marker COL1 decreased compared to control samples. LIPUS also has potent anti-inflammatory effects by reducing IL6 and IL8 and maintaining its ability to boost chondrogenesis.

These results suggest that the combination of LIPUS and piezoelectric hydrogels promotes the differentiation of ASCs encapsulated in a 3D hydrogel by reducing the inflammatory milieu, thus representing a promising tool in the field of cartilage TE.

Acknowledgements: This work received funding from the European Union's Horizon 2020 research and innovation program, grant agreement No 814413, project ADMAIORA (AdvanceD nanocomposite MAterIals for in situ treatment and ultRAsound-mediated management of osteoarthritis).

Management of ankle arthritis in young patients is challenging. Although ankle arthrodesis gives consistent pain relief, it leads to loss of function and adjacent joint arthritis. Ankle joint distraction (AJD) has been shown to give good outcomes in adults with osteoarthritis or post-traumatic arthritis. The efficacy in children or young adults and those with juvenile idiopathic arthritis is less well evidenced.

Clinical notes and radiographs of all patients (n=6) managed with AJD in one tertiary referral centre were retrospectively reviewed. Radiographs were taken pre-surgery, intra-operatively, 1 month following frame removal and at the last follow up, tibiotalar joint space was assessed using ImageJ software. Measurements were taken at the medial, middle and lateral talar dome using frame components as reference. Radiographic data for patients with a good clinical outcome was compared with those who did not.

At time of surgery mean age was 16.1 years (12 – 25 years). Mean follow up was 3.4 years (1.5 – 5.9 years). Indications were juvenile idiopathic arthritis (4) post-traumatic (1) and post-infective arthritis (1). Three patients at last follow up had a good clinical outcome. Two patients required revision to arthrodesis (1.3 and 2.4 years following distraction). One patient had spontaneous fusion. One patient required oral antibiotics for pin site infection.

Inter-observer reliability was 95%. Mean joint space was 1.17mm (SD = 0.87mm) pre-operatively which increased to 6.72mm (SD = 2.23mm) at the time of distraction and 2.09mm (SD = 1.14mm) at the time of removal. At one-year follow up, mean joint space was 1.96mm (SD = 1.97mm).

Outcomes following AJD in this population are variable although significant benefits were demonstrated for 50% of the patients in this series. Radiographic joint space preoperatively did not appear to be associated with need for arthrodesis. Further research in larger groups of young patients is required.

Recent studies suggested that both the soluble protein of the mesenchymal stromal cell (MSC) secretome, as well as the secreted extracellular vesicles (EVs) promote bone regeneration. However, there is limited knowledge of the changes in MSC secretome vesicular fraction during aging. We therefore aimed to characterize the release profiles and cargo of EVs from MSCs of different chronological ages.

Conditioned medium (CM) was collected from 13 bone marrow MSC strains (20-89 years) and from one MSC strain derived from human induced pluripotent stem cells (iPSCs). The EV-containing fraction was enriched with ultracentrifugation. The number of particles in the CM was evaluated by nanoparticle tracking analysis (NTA), and the number of EVs was evaluated by flow cytometry (FC) after staining with cell-mask-green and anti-CD81 antibody. EV cargo analysis was conducted using next-generation sequencing (NGS).

Our data confirmed the release of EVs from all MSC strains used in the study. There were no correlations between the number of particles and the number of EVs released in the CM, and between the number of EVs released and the strain age. Nevertheless, some of the lowest concentrations of EVs were found in the CM of strains over 70 years of age, which exhibited a low/absent chondrogenic and osteogenic differentiation potential. In contrast, iPSC-MSCs, which exhibited a high growth and three-lineage differentiation potential, released a similar amount of EVs as the best performing bone marrow MSC strain. NGS analysis identified several microRNAs that were significantly enriched in EVs of young MSC strains exhibiting low senescence, and those that were enriched in EVs of strains exhibiting high differentiation potentials. Gender had no influence on microRNA profiles in EVs or releasing MSCs.

Taken together, our data provides new insights into the properties of MSC vesicular secretome and its therapeutic potential during aging.

Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions.

PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and QUADAS-2 analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared.

9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies.

This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.

Degeneration of the intervertebral disc (IVD), and subsequent low back pain, is an almost inevitable cause of disability. The underlying mechanisms are complex and current therapeutic strategies mainly focus on symptomatic relief rather than on the intrinsic regeneration of the IVD. This talk will provide an overview of special anatomical features and the composition of the IVD as well as its cellular microenvironment. Selected promising conceptional regenerative approaches will be discussed.

The quest for optimal treatment of acute distal tibiofibular syndesmotic disruptions is still in progress. Using suture-button repair devices is one of the dynamic stabilization options, however, they may not be always appropriate for stabilization of length-unstable syndesmotic injuries. Recently, a novel screw-suture repair system was developed to address such issues. The aim of this study was to investigate the performance of the novel screw-suture repair system in comparison to a suture-button stabilization of unstable syndesmotic injuries.

Eight pairs of human cadaveric lower legs were CT scanned under 700 N single-leg axial loading in five foot positions – neutral, 15° external/internal rotation and 20° dorsi-/plantarflexion – in 3 different states: (1) pre-injured (intact); (2) injured, characterized by complete syndesmosis and deltoid ligaments cuts simulating pronation-eversion injury types III and IV as well as supination-eversion injury type IV according to Lauge-Hansen; (3) reconstructed, using a screw-suture (FIBULINK, Group 1) or a suture-button (TightRope, Group 2) implants for syndesmotic stabilization, placed 20 mm proximal to the tibia plafond. Following, all specimens were: (1) biomechanically tested over 5000 cycles under combined 1400 N axial and ±15° torsional loading; (2) rescanned. Clear space (diastasis), anterior tibiofibular distance, talar dome angle and fibular shortening were measured radiologically from CT scans. Anteroposterior (AP), axial, mediolateral and torsional movements at the distal tibiofibular joint level were evaluated biomechanically via motion tracking.

In each group clear space increased significantly after injury (p ≤ 0.004) and became significantly smaller in reconstructed compared with both pre-injured and injured states (p ≤ 0.041). In addition, after reconstruction it was significantly smaller in Group 1 compared to Group 2 (p < 0.001). AP and axial movements were significantly smaller in Group 1 compared with Group 2 (p < 0.001). No further significant differences were identified/detected between the groups (p ≥ 0.113).

Although both implant systems demonstrate ability for stabilization of unstable syndesmotic injuries, the screw-suture reconstruction provides better anteroposterior translation and axial stability of the tibiofibular joint and maintains it over time under dynamic loading. Therefore, it could be considered as a valid option for treatment of syndesmotic disruptions.

The anterior cruciate ligament (ACL) is the connective tissue located at the end of long bones providing stability to the knee joint. After tear or rupture clinical reconstruction of the tissue remains a challenge due to the particular mechanical properties required for proper functioning of the tissue. The outstanding mechanical properties of the ACL are characterized by a viscoelastic behavior responsible of the dissipation of the loads that are transmitted to the bone. These mechanical properties are the result of a very specialized graded extracellular matrix that transitions smoothly between the heterotypic cells, stiffness and composition of the ACL and the adjacent bone. Thus, mimicking the zonal biochemical composition, cellular phenotype and organization are key to reset the proper functioning of the ACL.

We have previously shown how the biochemical composition presented to cells in electrospun scaffolds results in haptokinesis, reverting contact-guidance effects.^[1] Here, we demonstrate that contact guidance can also be disrupted by structural parameters in aligned wavy scaffolds. The presentation of a wavy fiber arrangement affected the cell organization and the deposition of a specific ECM characteristic of fibrocartilage. Cells cultured in wavy scaffolds grew in aggregates, deposited an abundant ECM rich in fibronectin and collagen II, and expressed higher amounts of collagen II, X and tenomodulin as compared to aligned scaffolds. In-vivo implantation in rabbits of triphasic scaffolds accounting for aligned-wavy-aligned zones showed a high cellular infiltration and the formation of an oriented ECM, as compared to traditional aligned scaffolds.^[2]

Odontoid fracture of the second cervical vertebra (C2) is the most common spinal fracture type in elderly patients. However, very little is known about the biomechanical fracture mechanisms, but could play a role in fracture prevention and treatment. This study aimed to investigate the biomechanical competence and fracture characteristics of the odontoid process.

A total of 42 human C2 specimens (14 female and 28 male, 71.5 ± 6.5 years) were scanned via quantitative computed tomography, divided in 6 groups (n = 7) and subjected to combined quasi-static loading at a rate of 0.1 mm/s until fracturing at inclinations of −15°, 0° and 15° in sagittal plane, and −50° and 0° in transverse plane. Bone mineral density (BMD), specimen height, fusion state of the ossification centers, stiffness, yield load, ultimate load, and fracture type according to Anderson and d'Alonzo were assessed.

While the lowest values for stiffness, yield, and ultimate load were observed at load inclination of 15° in sagittal plane, no statistically significant differences could be observed among the six groups (p = 0.235, p = 0.646, and p = 0.505, respectively). Evaluating specimens with only clearly distinguishable fusion of the ossification centers (n = 26) reveled even less differences among the groups for all mechanical parameters. BMD was positively correlated with yield load (R² = 0.350, p < 0.001), and ultimate load (R² = 0.955, p < 0.001), but not with stiffness (p = 0.070). Type III was the most common fracture type (23.5%).

These biomechanical outcomes indicate that load direction plays a subordinate role in traumatic fractures of the odontoid process in contrast to BMD which is a strong determinant of stiffness and strength. Thus, odontoid fractures appear to result from an interaction between load magnitude and bone quality.

The use of mesenchymal stem cell (MSCs) for intervertebral disc (IVD) regeneration has been extensively explored in the last two decades. MSCs are potent cell types that can be easily and safely harvested due to their abundancy and availability. Moreover, they are characterized by the capacity to differentiate towards IVD cells as well as release growth factors to support resident cell metabolism and recruit local progenitor cells to induce endogenous repair of degenerated IVDs. This talk will outline the characteristics of the main MSC sources and their effect towards IVD regeneration based on available preclinical and clinical evidence. In addition, innovative aspects of MSC-derived cell-free therapies will also be discussed.

The biological understanding for the disease progression osteoarthritis (OA) has uncovered specific biomarkers from either synovial fluid, articular chondrocytes or synoviocytes that can be used to diagnose the disease. Examples of these biomarkers include interleukin-1β (IL-1β) or collagen II fragments (1, 2). In parallel, isolation of chondrocytes or bone marrow derived mesenchymal stromal cells (MSCs) has yielded cell-based strategies that have shown long- term beneficial effects in a specific cohort of patients, specifically in traumatic cartilage lesions (2). This latter finding shows that patient stratification of OA is an important tool to both match patients for a specific treatment and to develop novel therapies, especially disease modifying drugs. In order to create disease stage specific therapies, the use of next generation analysis tools such as RNAseq and metabolomics, has the potential to decipher specific cellular and molecular endotypes. Alongside greater understanding of the clinical phenotype (e.g. imaging, pain, co- morbidities), therapies can be designed to alleviate the symptoms of OA at specific points of the disease in patients. This talk will outline the current biological understanding of OA and discuss how patient stratification could assist in the design of innovative therapies for the disease.

Acknowledgements: This presentation was supported by the COST action, CA21110 – Building an open European Network on Osteoarthritis Research (NetwOArk)

In healthy subjects, respiratory maximal volumes are highly dependent on the sagittal range of motion of the T7-T10 segment. In AIS, the abolition of T7-T10 dynamics related to the stiffness induced by the apex region in Lenke IA curves could harm ventilation during maximal breathing. The aim of this study was to analyze the dynamics of the thoracic spine during deep breathing in AIS patients and in healthy matched controls. This is a cross-sectional, case-control study. 20 AIS patients (18 girls, Cobb angle, 54.7±7.9°; Risser 1.35±1.2) and 15 healthy volunteers (11 girls) matched in age (12.5 versus 15.8 yr. mean age) were included. In AIS curves, the apex was located at T8 (14) and T9 (6). Conventional sagittal radiographs of the whole spine were performed at maximal inspiration and exhalation. The ROM of each spinal thoracic functional segment (T1-T7, T7-T10, T10-T12) and the global T1-T12 ROM were measured. In healthy subjects, the mean T1-T12 ROM during forced breathing was 16.7±3.8. AIS patients showed a T1-T12 ROM of 1.1±1.5 (p<0.05), indicating a sagittal stiffness of the thoracic spine. A wide T7-T10 ROM (15.3±3.0) was found in healthy controls (91.6% of the T1–T12 ROM). AIS patients showed only 0.4±1.4 ROM at T7-T10 (36.4% of the T1-T12 ROM) (p<0.001). There was a significant positive correlation between the magnitude of T7-T10 kyphosis in maximal exhalation and both FVC (% of predicted FVC) and FEV1. In conclusion, Lenke 1A AIS patients show a restriction of the thoracic spine motion with an almost complete abolition of T7-T10 ROM, a crucial segment for deep breathing. T7-T10 stiffness could explain the ventilatory limitations found in AIS patients.

Tip-apex distance (TAD) has long been discussed as a metric for determining risk of failure in fixation of peritrochanteric hip fractures. This study seeks to investigate risk factors including TAD for hospital readmission one year after hip fixation surgery.

A retrospective review of proximal hip fractures treated with single screw intramedullary devices between 2016 and 2020 was performed at a 327 bed regional medical center. Patients included had a postoperative follow-up of at least twelve months or surgery-related complications developing within that time.

44 of the 67 patients in this study met the inclusion criteria with adequate follow-up post-surgery. The average TAD in our study population was 19.57mm and the average one year readmission rate was 15.9%. 3 out of 6 patients (50%) with a TAD > 25mm were readmitted within one year due to surgery-related complications. In contrast, 3 out of 38 patients (7.9%) with a TAD < 25mm were readmitted within one year due to surgery-related complications (p=0.0254). Individual TAD measurements, averaging 22.05mm in patients readmitted within one year of surgery and 19.18mm in patients not readmitted within one year of surgery were not significantly different between the two groups (p=0.2113).

Our data indicate a significant improvement in hospital readmission rates up to one year after hip fixation surgery in patients with a TAD < 25mm with a decrease in readmissions of over 40% (50% vs 7.9%). This result builds upon past investigations by extending the follow-up time to one year after surgery and utilizing hospital readmissions as a metric for surgical success. With the well-documented physical and financial costs of hospital readmission after hip surgery, our study highlights a reduction of TAD < 25mm as an effective method of improving patient outcomes and reducing financial costs to patients and medical institutions.

Osteoarthritis (OA) is the most common degenerative joint disorder. Its multifactorial etiology includes age, sex, joint overloading, genetic or nervous influences. In particular, the autonomic nervous system is increasingly gaining in importance. Its two branches, the sympathetic (SNS) and parasympathetic nervous system, are well-balanced under healthy conditions. OA patients seem to be prone to an autonomic imbalance and therefore, we analyzed their autonomic status.

More than 200 participants including patients with early and late stage knee OA (before and 1 year after knee replacement surgery) and healthy probands (age-matched) were analyzed. Heart rate variability was measured via electrocardiogram to assess long-term sympathetic (low-frequency=LF) and parasympathetic (high-frequency=HF, pRR50) activities or general variability (RMSSD, SDRR). Serum cortisol concentrations were measured by ELISA. Perceived chronic stress (PSQ) was assessed via questionnaire. Multivariant regression was performed for data analysis. LF/HF value of early OA was slightly increased compared to healthy controls but significantly higher compared to late OA patients before (p>0.05) and after TKR (p>0.01). HF in late OA patients before TKR was significantly decreased compared to patients after TKR (p>0.001) or healthy controls (p>0.05). Healthy probands exhibited the highest SDRR values, early OA patients had slightly lower levels and late OA patients before TKR displayed significantly reduced SDRR (p>0.001). The same differences were observed in pRR50 and RMSSD. Serum cortisol concentrations and PSQ scores increased in late OA patients before TKR. At the time point of TKR, women with beta blocker medication had significantly higher age (71 ± 9 years) than those without (63 ± 12 years)(p>0.01). An autonomic dysfunction with sympathetic dominance occurs in OA patients. The fact that beta blocker medication in women delayed the need of TKR indicates that SNS inhibition might counteract OA. Future therapeutic interventions for OA should consider a systemic approach with special regard on the ANS.