C. Mori

Dental pulp stem cells: osteogenic differentiation and gene expression.

Dental pulp stem cells (DPSCs) are an adult stem cell population with high proliferative potential and the ability to differentiate in many cell types, and this has led scientists to consider these cells to be an alternative source of postnatal stem cells comparable to mesenchymal stem cells from bone marrow. In this work, we studied the osteoblastic phenotype developed by DPSCs cultured in osteogenic medium. In particular, we analyzed the expression of the typical osteoblast markers such as alkaline phosphatase, collagen type I, osteocalcin, osteopontin, as well as mineralized matrix production. Furthermore, the gene expression during DPSC differentiation into osteoblastic cells was studied by microarray technology. Using microarray and reverse transcriptase–polymerase chain reaction (RT‐PCR) analysis, we found that IGFBP‐5, JunB, and NURR1 genes are upregulated during the differentiation of DPSCs. These data indicate that opportunely differentiated DPSCs show a correct osteoblastic phenotype. Therefore, during the osteoblastic differentiation process, IGFBP‐5, JunB, and NURR1 gene expression is significantly increased.

Soluble decoy receptor 3 modulates the survival and formation of osteoclasts from multiple myeloma bone disease patients

Decoy receptor 3 (DcR3), a member of the tumor necrosis factor (TNF) receptor superfamily, is known to be involved in cell survival and osteoclast (OC) formation. In this study, we show that malignant plasma cells and T lymphocytes from multiple myeloma (MM) bone disease patients, as well as Karpas 909, a human myeloma cell line, directly produce DcR3. By interacting with FasL, this molecule could inhibit OC apoptosis. In fact, the use of a neutralizing anti-DcR3 antibody induces a reduction of cell viability with a consequent increase of apoptotic cell number, the activation of caspase-8 and -3, and DNA fragmentation. Furthermore, we show that DcR3 supports OC formation in samples from MM patients through the upregulation of RANKL and TNFα by T lymphocytes and only TNFα by CD14+ cells. In conclusion, our data provide the first evidence of the expression of DcR3 in MM, and the involvement of this molecule in supporting the survival and formation of OCs from MM bone disease patients. The production of DcR3 by T lymphocytes confers these cells a role in the pathogenesis of bone disease associated with MM.

Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients

BackgroundTotal hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads.MethodsA total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling.ResultsAt a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose.ConclusionsOn the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads.

Osteoblasts display different responsiveness to TRAIL-induced apoptosis during their differentiation process.

Apoptosis can occur throughout the life span of osteoblasts (OBs), beginning from the early stages of differentiation and continuing throughout all stages of their working life. Here, we investigated the effects of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) on normal human OBs showing for the first time that the expression of TRAIL receptors is modulated during OB differentiation. In particular, the TRAIL receptor ratio was in favor of the deaths because of the low expression of DcR2 in undifferentiated OBs, differently it was shifted toward the decoys in differentiated ones. Undifferentiated OBs treated with TRAIL showed reduced cell viability, whereas differentiated OBs displayed TRAIL resistance. The OB sensitiveness to TRAIL was due to the up-regulation of DR5 and the down-regulation of DcR2. The main death receptor involved in TRAIL-reduced OB viability was DR5 as demonstrated by the rescue of cell viability observed in the presence of anti-DR5 neutralizing antibody. Besides the ratio of TRAIL receptors, the sensitivity of undifferentiated OBs to TRAIL-cytotoxic effect was also associated with low mRNA levels of intracellular anti-apoptotic proteins, such as cFLIP, the activation of caspase-8 and -3, as well as the DNA fragmentation. This study suggests that apoptotic effect exerted by TRAIL/TRAIL-receptor system on normal human OB is strictly dependent upon cell differentiation status.

Hybrid external fixation in the treatment of tibial pilon fractures: A retrospective analysis of 162 fractures

OBJECTIVES To determine the efficacy of hybrid external fixation in the treatment of tibial pilon fractures. DESIGN Retrospective, multicentre study. PATIENTS/PARTICIPANTS Adult patients with tibial pilon fractures treated with hybrid external fixation. INTERVENTION Fracture reduction with ligamentotaxis and fixation with XCaliber hybrid external fixator. MAIN OUTCOME MEASUREMENTS Fracture union, complications, functional outcome (Mazur Ankle Score). RESULTS Union was obtained in 159 fractures at an average of 125days; there were three delayed unions and three non-unions. The most frequent complication was superficial pin-track infections (48), all of which responded to local wound care and antibiotics. There were no deep infections and no DVT. Only one fracture had loss of reduction that required frame revision. The overall functional scores were 91 (excellent) for AO/OTA type A fractures, 89 (good) for type B fractures, and 75 (satisfactory) for type C fractures. CONCLUSIONS Hybrid external fixation is an effective method of stabilising tibial pilon fractures, particularly those with marked comminution. The minimally-invasive technique and stable fixation enable early mobilisation, with good functional results and minimal complications. LEVEL OF EVIDENCE Level IV Case series.

Micromotion in the fracture healing of closed distal metaphyseal tibial fractures: A multicentre prospective study.

The dynamic locking screw (DLS) in association with minimally invasive plate osteosynthesis (MIPO) in a bridging construct for simple metadiaphyseal long bone fractures enables modulation of the rigidity of the system and facilitates the development of early and triplanar bone callus. Twenty patients affected by distal tibial fracture were treated with MIPO bridging technique and DLS at the proximal side of the fracture. Time of consolidation, quality of the reduction, complications and American Orthopaedic Foot and Ankle Society (AOFAS) score were monitored and the results compared with those from a control group treated with only standard screws on both fracture sides. Student t-test for independent samples was used for the comparison of means between the two groups. Chi-square test was used for the comparison of proportions. A multiple logistic regression model was constructed to assess the possible confounding effects. Performance was considered significant for p<0.05. The mean healing time was 17.6 ± 2.8 weeks in the group treated with standard screws and 13.5 ± 1.8 weeks in the group treated with DLS (t=5.5, p<0.0001). The DLS was associated with early healing and triplanar bone callus.

Heel displaced intra-articular fractures treated with mini-calcaneal external fixator

INTRODUCTION Treatment of displaced heel fractures is controversial; however, ORIF is widely described in the literature to be the gold-standard. Percutaneous reduction and monolateral external fixation is gaining increasing attention because it provides a good and stable reduction, and minimises soft tissue complications due to open surgery, such as deep infections and delays in wound healing. The aim of this study was to show that the new Orthofix Calcaneal Minifixator (six pins) provides a greater stability than the four-pin version to enable a better and more stable reduction, an earlier weight-bearing (30 days) and improved functional outcomes. METHODS A series of 69 consecutive closed heel intraarticular displaced fractures treated with the new Orthofix Calcaneal Minifixator were evaluated. Patients were assessed clinically with the Maryland Foot Score and radiologically with standard radiographs. RESULTS The clinical results at follow-up were excellent in 37 cases (53.6%), good in 27 (39.2%), fair in two (2.9%) and poor in three (4.3%). The mean preoperative Böhlers angle was 5.2˚ (range 0-18˚) and the mean postoperative value was 28.5˚ (range 16-38˚). CONCLUSION The excellent functional outcomes were despite some radiological images of imperfect posterior facet anatomical reduction and seemed to correlate with the use of a good and stable minimally-invasive surgical technique. This technique enabled early weight-bearing, minimised complications, respected the delicate biology of this anatomical site and restored the good heel volume and Böhler angle.

Is distal locking with short intramedullary nails necessary in stable pertrochanteric fractures? A prospective, multicentre, randomised study

We investigated whether a proximal femoral nail can be implanted without a distal locking screw in AO/OTA 31-A1 and 31-A2 pertrochanteric stable femur fractures. A multicentre, randomised study was conducted in six level-two trauma centres in our area (Puglia, Italy). A total of 333 patients received their allocated intervention (162 in the locking group [LG] and 171 in the unlocking group [UG]) and 266 patients were included in the final analysis at 1year. Our data showed no statistically significant difference between the two groups at 1-year follow-up for ability to walk, SF-36 questionnaire results, residual pain (visual analogue scale [VAS] score) and level of overall satisfaction. There were also no statistically significant differences between groups for mortality and length of hospital stay. Conversely, the UG was associated with shorter operation and fluoroscopy times, shorter surgical incision length, and less blood loss and residual thigh pain. Pertrochanteric stable fractures (31-A1, 31-A2) can be treated successfully with intramedullary nails without distal locking, reducing patient and clinical personnel radiation exposure and sanitary costs (surgery time and screws costs).

L’osteosintesi nelle fratture periprotesiche di ginocchio: una chirurgia difficile

The incidence of periprosthetic fractures after total knee arthroplasty appears to be on the rise as a result of the increasing longevity of patients with knee prosthetic implants. The most common pattern involves the supracondylar area of the distal femur above a well-fixed prosthesis. If a periprosthetic fracture occurs, an appropriate treatment method should be selected considering different factors.

Il trattamento definitivo delle fratture del terzo prossimale dell’omero con fissatore esterno

Proximal humeral fractures are common finding, comprising 5–7% of all fractures, and being more common in the elderly. The incident of the proximal humerus fractures has been on the rise during the past decade. Many treatment options are available, such as conservative treatment, open reduction internal fixation (ORIF), joint replacement, percutaneous fixation and external fixation. ORIF has shown to be associated with surgical trauma, higher infection rates, avascular necrosis of the humeral head, and neurovascular lesions. Therefore, the trend has changed in the past few years from massive internal fixation to closed reduction and minimal fixation. The advantages of closed reduction and external fixation consist in the possibility of preserving blood supply to bone fragments, the absence of blood loss and the possibility of performing surgery under brachial plexus block.