Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is useful for the diagnosis of pancreatic masses. According to three meta-analyses, the sensitivity, specificity, and accuracy of EUS-FNA are 84-92%, 96-98%, and 86-91%, respectively. However, the occurrence of false-negative and false-positive results indicates that the diagnostic performance of EUS-FNA needs to be improved. Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is used for the characterization of pancreatic masses and can be applied to improve the performance of EUS-FNA. When CH-EUS is used to evaluate intratumor blood flow, an avascular area inside the pancreatic mass that is considered to be fibrosis is often detected. This area can be avoided by performing EUS-FNA under CH-EUS guidance. In this review, we summarize the data on contrast-enhanced harmonic endoscopic ultrasound-guided fine-needle aspiration (CH-EUS-FNA), which suggest that its benefit is still a matter of debate. Of eight studies analyzed, only one showed that CH-EUS improved the sensitivity of EUS-FNA. The future challenge is to determine under what circumstances CH-EUS-FNA is useful.

The ideal surgical treatment of femoral neck fractures remains controversial. When treating these fractures with internal fixation, many fixation constructs exist. The primary aim of this study was to evaluate the incidence and specific risk factors associated with complication and re-operation following fixation of intracapsular proximal femoral fractures using the Targon-FN system (B.Braun Melsungen AG). A secondary aim was to identify if lateral prominence of the implant relative to the lateral border of the vastus ridge was a specific risk factor for elective plate removal. Methodically, a retrospective case series was conducted of all consecutive adult patients treated at a single level 1 trauma center in Switzerland for an intracapsular proximal femoral fracture with the Targon-FN. Demographic data were collected. Patients with a follow-up of less than three months were excluded. Complications as well as plate position were recorded. Statistical analysis to identify specific risk factors for re-operation and complications was performed. In result, a total of 72 cases with intracapsular femoral neck fractures were treated with the Targon-FN locking plate system between 2010 and 2017. Thirty-four patients (47.2%) experienced one or more complications. The most common complication was mechanical irritation of the iliotibial band (ITB) (23.6%, n = 17). Complications included intraarticular screw perforation (6.9%, n = 5), avascular necrosis (5.6%, n = 4), non-union (5.6%, n = 4) among others. In total, 46 re-operations were required. Younger age, fracture displacement and time to postoperative weight bearing were identified as risk factors for re-operation. In conclusion, intracapsular femoral neck fractures treated with the Targon-FN system resulted in a high rate of post-operative complication and re-operation. Statistical analysis revealed patient age, fracture displacement, time to postoperative full weight bearing were risk factors for re-operation. The main limitation is the limited number of cases and a short follow-up of less than 12 months in a subgroup of our patients.

Stimulating meniscus regeneration using meniscal progenitor cells has been suggested as a promising new strategy. However, there is a lack of studies which decisively identify and characterize progenitor cell populations in human meniscus tissues. In this study, donor-matched progenitor cells were isolated via selective fibronectin adhesion from the avascular and vascular regions of the meniscus and chondroprogenitors from articular cartilage (n = 5). The mixed populations of cells from these regions were obtained by standard isolation techniques for comparison. The colony formation efficacy of avascular progenitors, vascular progenitors and chondroprogenitors was monitored using Cell-IQ® live cell imaging. Proliferation rates of progenitors were compared with their mixed population counterparts. Cell surface markers indicative of mesenchymal stromal cells profile and progenitor markers were characterized by flow cytometry in all populations. The fibrochondrogenic capacity was assessed via fibrochondrogenic differentiation and measuring GAG/DNA content and morphology. All meniscal progenitor and chondroprogenitor populations showed superior colony forming efficacy and faster proliferation rates compare to their mixed populations. Progenitor populations showed significantly higher positivity for CD49b and CD49c compared to their mixed population counterparts and chondroprogenitors had a higher positivity level of CD166 compared to mixed chondrocytes. GAG/DNA analysis demonstrated that progenitor cells generally produced more GAG than mixed populations. Our study demonstrates that the human meniscus contains meniscal progenitor populations in both the avascular and vascular regions. Meniscal progenitors derived from the vascular region exhibit enhanced proliferative and fibrochondrogenic characteristics compared to those from the avascular region; this may associate with the enhanced meniscal healing potential in the vascular region. These findings build on the body of evidence which suggests that meniscal progenitors represent an attractive cell therapy strategy for meniscal regeneration.

Vertebral body erosion is a rare late complication of tracheostomy. Here we present the case of a 30-year-old female patient, in a vegetative state after severe brain injury, with a permanent tracheostomy and prolonged mechanical ventilation, who suffered from recurrent episodes of severe air leakage with oxygenation drop due to a puncture in the tracheostomy tube cuff. A neck computed tomography (CT) detected destruction of two vertebral bodies, C7 and Th1, and a bony fragment - a remnant of C7 penetrated the trachea and probably repetitively punctured the inflated cuff. A biopsy of the C7 vertebral body was performed under CT guidance to rule out osteomyelitis. The biopsy revealed necrotic bone spicules surrounded by vascular-rich fibrous tissue, without evidence of inflammation. C7 vertebral body avascular osteonecrosis was diagnosed. The case highlights the importance of monitoring cuff pressure during long-term use of cuffed endotracheal tubes to avoid hyperinflation and subsequent ischemic complications.

BACKGROUND: Avascular necrosis (AVN) of the talus most commonly occurs secondary to trauma. Significant bone loss and collapse in severe talar AVN remains an operative challenge. Tibiotalocalcaneal arthrodesis (TTC) using femoral head allograft is at risk of collapse and subsidence. The use of a void-filling titanium truss can mitigate against this. This study describes the use of a novel keystone shaped 3D-printed titanium truss for treatment of severe talar AVN.
METHODS: Three patients with end-stage AVN of the talus were included. Each patient underwent a TTC arthrodesis with a custom-made, 3D-printed, keystone-shaped, truss implant in conjunction with a hindfoot intramedullary nail. Modified patient American Orthopaedic Foot & Ankle Society (AOFAS) scores were recorded at the preoperative, 6-month, 12-month, and annual postoperative timepoints.
RESULTS: All patients progressed to satisfactory radiological union by one year. Mean follow up time was 32 months (24-48 months). Mean preoperative modified AOFAS score was 5. There was progressive improvement in AOFAS scores from 6 months postoperatively. Mean modified AOFAS score improved from 28 at 6 months to 37 at 2 years postoperatively.
CONCLUSIONS: Custom-made 3D-printed titanium trusses provide promising outcomes for treating severe AVN of the talus. The \"keystone\" design is advantageous as it allows for bone stock preservation and conforms to the shape of the native calcaneum. All patients showed progressive improvements in outcomes at sequential time intervals postoperatively. The implant provides a strong mechanical structure resisting collapse and subsidence during the arthrodesis process.
METHODS: Level IV, retrospective case series.

Oxygen is essential to cell survival and tissue function. Not surprisingly, ischemia resulting from myocardial infarction induces cell death and tissue necrosis. Attempts to regenerate myocardial tissue with cell based therapies exacerbate the hypoxic stress by further increasing the metabolic burden. In consequence, implanted tissue engineered cardiac tissues suffer from hypoxia-induced cell death. Here, we report on the generation of oxygen-generating hydrogels composed of calcium peroxide (CPO) laden gelatin methacryloyl (GelMA). CPO-GelMA hydrogels released significant amounts of oxygen for over a period of 5 days under hypoxic conditions (1% O2). The released oxygen proved sufficient to relieve the metabolic stress of cardiac side population cells that were encapsulated within CPO-GelMA hydrogels. In particular, incorporation of CPO in GelMA hydrogels strongly enhanced cell viability as compared to GelMA-only hydrogels. Importantly, CPO-based oxygen generation reduced cell death by limiting hypoxia-induced necrosis. The current study demonstrates that CPO based oxygen-generating hydrogels could be used to transiently provide oxygen to cardiac cells under ischemic conditions. Therefore, oxygen generating materials such as CPO-GelMA can improve cell-based therapies aimed at treatment or regeneration of infarcted myocardial tissue.

BACKGROUND: Accelerated femoral head avascular necrosis after a single dose intra-articular steroid injection is a rare pathology. Few cases were reported in the literature. Most cases were managed with total hip arthroplasty.
METHODS: In this study, we report two rare cases of destructive osteonecrosis of the femoral head. Both patients presented with hip osteoarthritis that failed nonoperative measures. A single intra-articular corticosteroid injection was administered for each patient. Both patients had femoral head destruction and significant resorption at 14 and 11 weeks, respectively. Septic arthritis was ruled out by blood tests and joint aspiration. Total hip arthroplasty (THA) was undertaken and histology reports confirmed the osteonecrosis. The postoperative follow-up was uneventful with satisfactory hip function.
CONCLUSIONS: Destructive osteonecrosis of the femoral head is a rare catastrophic potential complication of intra-articular corticosteroid injection. Hence, physicians must consider this complication when counseling patients before an intra-articular corticosteroid hip injection.

Semilunar osteonecrosis or Kienböck\'s disease has a low prevalence, usually occurring in young men aged between 20 and 40 years. This disease is even less common in childhood. The aetiology varies, with postulation of the vascular trauma theory and the non-traumatic theory, in which the disease is caused by various other mechanisms. Semilunar involvement can occur with bone oedema, fragmentation, and scapholunate misalignment and progresses towards collapse. We present the case of an adolescent boy with Kienböck\'s disease, with no attributable traumatic antecedent, who developed a complex classification injury on the Litchman scale. Partial improvement of symptoms was achieved with conservative treatment but without definitive pain elimination. Future surgery for this patient is currently being discussed, bearing in mind his skeletal maturity and the pathophysiological progression of the injury.

Avascular necrosis (AVN) of the femoral head following slipped capital femoral epiphysis (SCFE) is a serious complication that often leads to a permanent disability. Radiological findings of AVN may take up to two years to become apparent. This means painful waiting for children, parents, and treating teams. We would like to describe a new radiological sign that we noted in four patients. The sign has been named as the crescent moon sign or eid crescent sign. It may become visible as early as six weeks following surgery, and it carries a good prognosis that the femoral head is viable and will not develop AVN. Two out of the four patients were treated in our hospital by Ganz surgical dislocation. The other two patients had been featured in other publications, but the significance of the moon crescent signs, which were present, was not recognized or appreciated. All four patients did not develop AVN. A relatively similar radiological sign has been described in talus bone fractures (Hawkins\' sign). Like SCFE, talus bone fractures have a high AVN rate. Both, the crescent moon sign and Hawkins\' sign carry a good prognosis and indicate that the bone blood supply is restored.

BACKGROUND: Gross total resection of arteriovenous malformations (AVMs) of the central nervous system confirmed by formal angiography is accepted as a cure for patients. In some cases, this may not be possible. Even though in these cases other treatment modalities such as endovascular embolization and radiotherapy can be used, long-term follow-up is lacking in the literature.
METHODS: Here we report a case of a 57-year-old woman with history of a right-sided parieto-occipital/periatrial AVM, initially treated with a combination of endovascular embolization and radiotherapy.
CONCLUSIONS: The patient subsequently presented (12 years later) with a symptomatic, enlarging, contrast-enhancing mass at the same location that was angiographically occult but ultimately proven to be an AVM on a background of reactive changes on pathology.