Screw-plate angulation of 130° or 135° and 120° in the stabilization of an unstable trochanteric femoral neck fracture

Correct positioning of the screw in the femoral head is the most important surgical challenge after the external reduction of an unstable femoral neck fracture. Rules of this challenge are very accurate, especially for osteoporotic elderly patients. We would like to point out the relationship between anatomy, mathematical pattern, and surgical procedure. Anatomically, the correct position for the screw must be in the lower half of the femoral head. From a mathematical point of view, in this position, the portion of a sphere's surface is higher and its volume is the highest. In some cases therefore, it is not technically possible to fix in good position the 130°or 135° screw. It could be of interest to provide surgeons with a 120° angulation screw-plate.     

Advantages of 70° arthroscope in management of ECRB tendinopathy

Lateral epicondylitis requires a challenging therapeutic management even for expert surgeons. With the failure of conservative treatment, the physician should consider a surgical choice. The purpose of the surgical procedure is to excise the degenerated tissue of extensor carpi radialis brevis tendon. This article describes the arthroscopic release, performed under direct visualization with a 70° scope; the aim is to encourage the use of this type of lens, versus the traditional 30° one. The patient is positioned in a modified lateral decubitus. After joint distension, a diagnostic arthroscopy of the posterior compartment is performed as first step. Then, an anterior compartment arthroscopic evaluation, a subsequent antero-lateral capsulectomy, and extensor carpi radialis brevis tendon exposition are performed with a 30° view. At this point, the 70° lens is switched and the tendon release is performed under direct control. The 70° lens allows a safer procedure, but requires a dedicated learning curve.     

Advantages of 70° arthroscope in management of ECRB tendinopathy

This retrospective study was done to evaluate the results of total knee arthroplasty performed on 32 patients with stiff knee, having a preoperative arc of movement between 0° and 50° (average 30°). This group of patients were matched with a group of 32 flexible knees, randomly selected from the same cohort of patients who underwent knee arthroplasty in our ward. At a mean follow-up of 4.5 years (min 2, max 11 years), seven patients of the stiff group reported complications (21.8% overall): four prosthetic infection that successively underwent removal of the implant, one skin necrosis 4 months after the intervention, one early contracture and one late stiffness of the knee. In the control group, in two cases, there was substitution of the implant due to periprosthetic infection. At the end of the study period, the clinical evaluation was not possible in four patients of the stiff and in two patients of the control group who underwent revision of the prosthetic components. An excellent or good clinical result was obtained in 92% of stiff group and in 96% of the control group patients. Although the final results achieved in these patients are worse than those of patients with flexible knee due to disadvantageous preoperative conditions and high complication rate, our results demonstrate the efficacy of the arthroplasty procedure as treatment of stiff knee.     

Primary stability of the Fitmore® stem: biomechanical comparison

Purpose

After clinical introduction of the Fitmore® stem (Zimmer), we noticed the formation of cortical hypertrophies in a few cases. We questioned whether (1) the primary stability or (2) load transfer of the Fitmore® stem differs from other stems unassociated with the formation of hypertrophies. We compared the Fitmore® stem to the well-established CLS® stem.

Methods

Four Fitmore® and four CLS® stems were implanted in eight synthetic femurs. A cyclic torque around the stem axis and a mediolateral cyclic torque were applied. Micromotions between stems and femurs were measured to classify the specific rotational implant stability and to analyse the bending behaviour of the stem.

Results

No statistical differences were found between the two stem designs with respect to their rotational stability (p = 0.82). For both stems, a proximal fixation was found. However, for the mediolateral bending behavior, we observed a significantly (p < 0.01) higher flexibility of the CLS® stem compared to the Fitmore® stem.

Conclusion

Hip stem implantation may induce remodelling of the periprosthetic bone structure. Considering the proximal fixation of both stems, rotational stability of the Fitmore® stem might not be a plausible explanation for clinically observed formation of hypertrophies. However, bending results support our hypothesis that the CLS® stem presumably closely follows the bending of the bone, whereas the shorter Fitmore® stem acts more rigidly. Stem rigidity and flexibility needs to be considered, as they may influence the load transfer at the implant–bone interface and thus possibly affect bone remodelling processes.     

Is xenotransplantation of embryonic stem cells a realistic option?

To test the purported immune privilege of embryonic stem cells (ESC) in the challenging setting of xenotransplantation, 14 immunocompetent baboons were subjected to a coronary artery occlusion-reperfusion sequence and, two weeks later, randomized to receive in-scar injections of culture medium or cardiac-committed mouse ESC engineered to express fluorescent reporter genes driven by cardiac-specific promoters. Two months after transplantation, left ventricular function, as assessed by echocardiography, deteriorated to a similar extent in control and treated baboons. This correlated with failure to identify the grafted cells by X-gal histology and immunofluorescence. Rejection did not seem to be mediated by xenoantibodies, but rather by T lymphocytes and natural killer cells as suggested by positive immunostaining for CD3 and CD56 early after transplantation. There was no increase in circulating levels of regulatory T cells. These data raise a cautionary note about the immune privilege of ESC and suggest that from a mere immunologic standpoint, ESC xenotransplantation is likely to be an unrealistic challenge.     

The effects of microenvironment in mesenchymal stem cell–based regeneration of intervertebral disc

Background contextRecent studies have demonstrated new therapeutic strategy using transplantation of mesenchymal stem cells (MSCs), especially bone marrow–derived MSCs (BM-MSCs), to preserve intervertebral disc (IVD) structure and functions. It is important to understand whether and how the MSCs survive and thrive in the hostile microenvironment of the degenerated IVD. Therefore, this review majorly examines how resident disc cells, hypoxia, low nutrition, acidic pH, mechanical loading, endogenous proteinases, and cytokines regulate the behavior of the exogenous MSCs.PurposeTo review and summarize the effect of the microenvironment in biological characteristics of BM-MSCs for IVD regeneration; the presence of endogenous stem cells and the state of the art in the use of BM-MSCs to regenerate the IVD in vivo were also discussed.Study designLiterature review.MethodsMEDLINE electronic database was used to search for articles concerning stem/progenitor cell isolation from the IVD, regulation of the components of microenvironment for MSCs, and MSC-based therapy for IVD degeneration. The search was limited to English language.ResultsStem cells are probably resident in the disc, but exogenous stem cells, especially BM-MSCs, are currently the most popular graft cells for IVD regeneration. The endogenous disc cells and the biochemical and biophysical components in the degenerating disc present a complicated microenvironment to regulate the transplanted BM-MSCs. Although MSCs regenerate the mildly degenerative disc effectively in the experimental and clinical trials, many underlying questions are in need of further investigation.ConclusionsThere has been a dramatic improvement in the understanding of potential MSC-based therapy for IVD regeneration. The use of MSCs for IVD degeneration is still at the stage of preclinical and Phase 1 studies. The effects of the disc microenvironment in MSCs survival and function should be closely studied for transferring MSC transplantation from bench to bedside successfully.     

Sources of human hematopoietic stem cells for transplantation—a review

Transplantation of hematopoietic stem cells provides a means of replacing a defective hematopoietic system in patients with a wide range of malignant and nonmalignant disorders that affect the blood forming tissue. The same procedure has also allowed dose-escalation of standard chemotherapy and radiotherapy in the treatment of malignant disease of nonhematological origin. Until recently, bone marrow has been the sole source of hematopoietic stem cells, but limitations of conventional bone marrow transplantation have stimulated a search for alternative sources and uses of stem cells. Fetal tissues (especially liver) are a recognized source of transplantable stem cells and offer the great advantage of reduced immunogenicity, potentially removing the problems of tissue type matching. Umbilical cord blood is also a rich source of stem cells and, although it contains alloreactive cells, it is readily available without special ethical constraints. Both fetal tissue and cord blood suffer the disadvantages of limited numbers of stem cells per donation, and there is much interest in the development of technologies for the safe and reliable expansion and/or pooling of stem and progenitor cells. The observation that small numbers of stem cells are found in the peripheral blood of adults has led to the exploitation of the blood as a further source of stem cells. The ability to mobilize these cells from the medullary compartment into the periphery by the use of chemotherapy and/or recombinant hematopoietic growth factors has enabled the collection of sufficient numbers of cells for transplantation purposes. All of these advances are increasing the options and the range of choices available to clinicians and patients in the arena of hematopoietic stem cell transplantation.     

Radiological identification of Zweymüller-type femoral stem prosthesis in revision cases

Introduction

Since 1979 the number of patients treated with femoral stems has continued to grow, as well as the number of stems with features similar to the Zweymüller prosthesis produced by different companies. Identification can be problematic in case requiring revision. In the present paper, we present an overview of morphometric differences between the different stem designs, which can be useful for radiologic identification in revision cases.

Methods

By doing some research on the Internet of specialized sites and worldwide literature, we searched for all femoral stems agreeing with Zweymüller principles (cementless, straight, tapered, rectangular cross-sectioned femoral stems).

Results

We found 26 different stems from different companies producing or having produced in the past the Zweymüller-type femoral stems for hip prosthesis.

Discussion

Accurate preoperative identification of the Zweymüller femoral stem type may be of critical importance to eventual outcomes following revision surgery. Each manufacturer has different instruments specific to the removal of their primary implants, and ensuring they are available can simplify the revision procedure significantly. Exact pre-operative planning is also necessary for selecting the correct ball head in cases where a stem is well-fixed and can be left in situ. The commonly used notation "Eurocone 12/14" provides no information about the actual taper angle. Whenever the stem is left in situ, the exact specifications of the taper must therefore be obtained from the manufacturer in order to use a metal sleeve that precisely fits it and the ball head. Failure to do so may result in severe complications, such as metallosis. In cases where it is not possible to identify the taper angle, the surgeon may even consider removal of the stem, though this significantly increases the surgical procedure's invasiveness. Only a single, uniform standard taper, such as that offered until 1994 by CeramTec, can solve these issues in the future.

Conclusion

The survival rate of the Zweymüller stems after ten years was 96 % and the complication rate was very low. Pre-operative identification of the femoral implant is of considerable importance for planning and correctly implementing revision procedures.

     

The in vitro myelin formation in neurospheres of human neural stem cells

Objective: To explore the culture conditions of human neural stem cells and to investigate the ultrastructure of neurospheres. Methods: The cells from the embryonic human cortices were mechanically dissociated. N2 medium was adapted to culture and expand the cells. The cells were identified by immunocytochemistry and EM was applied to examine the ultrastructure of neurospheres. Results: The neural stem cells from human embryonic brains were successfully cultured and formed typical neurospheres in suspension, and most of the cells expressed vimentin, which was a marker for neural progenitor cells, and the cells could differentiate into neurons, astrocytes and oligodendrocytes. In vitro myelin formation in neurospheres were observed at an early stageof culture. Conclusions: Human neural stem cells can be cultured from embryonic brains, can form the typical neurospheres in suspension in vitro and have the ability of myelinating, and may be potential source for transplantation in treating myelin disorders.     

Clinical potential of intravenous neural stem cell delivery for treatment of neuroinflammatory disease in mice?

While neural stem cells (NSCs) are widely expected to become a therapeutic agent for treatment of severe injuries to the central nervous system (CNS), currently there are only few detailed preclinical studies linking cell fate with experimental outcome. In this study, we aimed to validate whether IV administration of allogeneic NSC can improve experimental autoimmune encephalomyelitis (EAE), a well-established animal model for human multiple sclerosis (MS). For this, we cultured adherently growing luciferase-expressing NSCs (NSC-Luc), which displayed a uniform morphology and expression profile of membrane and intracellular markers, and which displayed an in vitro differentiation potential into neurons and astrocytes. Following labeling with green fluorescent micron-sized iron oxide particles (f-MPIO-labeled NSC-Luc) or lentiviral transduction with the enhanced green fluorescent protein (eGFP) reporter gene (NSC-Luc/eGFP), cell implantation experiments demonstrated the intrinsic survival capacity of adherently cultured NSC in the CNS of syngeneic mice, as analyzed by real-time bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and histological analysis. Next, EAE was induced in C57BL/6 mice followed by IV administration of NSC-Luc/eGFP at day 7 postinduction with or without daily immunosuppressive therapy (cyclosporine A, CsA). During a follow-up period of 20 days, the observed clinical benefit could be attributed solely to CsA treatment. In addition, histological analysis demonstrated the absence of NSC-Luc/eGFP at sites of neuroinflammation. In order to investigate the absence of therapeutic potential, BLI biodistribution analysis of IV-administered NSC-Luc/eGFP revealed cell retention in lung capillaries as soon as 1-min postinjection, resulting in massive inflammation and apoptosis in lung tissue. In summary, we conclude that IV administration of NSCs currently has limited or no therapeutic potential for neuroinflammatory disease in mice, and presumably also for human MS. However, given the fact that grafted NSCs have an intrinsic survival capacity in the CNS, their therapeutic exploitation should be further investigated, and-in contrast to several other reports-will most likely be highly complex.     

The posteroanterior 45° flexion weight-bearing radiograph of the knee

Biomechanical studies suggest that radiographs of the osteoarthritic knee taken in 30° to 60° of flexion more accurately demonstrate the true degree of articular cartilage loss than radiographs taken with the knee in full extension. Conventional anteroposterior weight-bearing full-extension radiographs were compared with posteroanterior 45° flexion weight-bearing radiographs of 35 patients with 45 symptomatic knees (90 compartments) presenting with suspected osteoarthritis. In 35 compartments, there was a 2-mm or greater loss of joint space in the 45° flexion views compared with those taken in full extension. Also, in 11 compartments (10 knees), there was a normal joint space on the full extension radiographs, but marked narrowing on the flexion view. Both results are statistically significant. It is concluded that the posteroanterior 45° flexion weight-bearing radiograph is a useful additional tool in the assessment of knees with early degenerative change.     

Effect of 30°C Heat on the Anaerobic Capacity of Heat Acclimatised Athletes

The main finding of this study was that for heat acclimatised athletes, there was no significant difference (p=0.58) in anaerobic capacity for temperate (21.8 ± 0.5 °C; 52 ± 5 % relative humidity) compared with warm conditions (29.6 ± 0.5 °C; 51 ± 9 % relative humidity). Anaerobic capacity was estimated using the maximal accumulated oxygen deficit (MAOD) during constant intensity cycling at 120% peak rate of O₂ consumption until exhaustion. This yielded mean MAOD values of 3.3 ± 0.9 and 3.5 ± 1.1 L for temperate and warm conditions, respectively. Peak post-exercise lactate values of 14.7 ± 3.8 and 14.4 ± 4.5 mmol·L^-1 for temperate and warm conditions respectively, were also not significantly different (p=0.72). Time to exhaustion (TTE) was similarly unchanged (p=0.56), being 175 ± 19 and 170 ± 18 s for temperate and warm conditions, respectively. These results suggest that the MAOD remains a valid test throughout environmental temperatures for the range of 20-30 °C when used with heat acclimatised athletes.Key Words: Maximal accumulated oxygen deficit, anaerobic metabolism, environmental temperature, maximal exercise     

Adult stem cell therapy beyond haemopoietic stem cell transplantation? An update

The lifesaving potential of haemopoietic stem cell transplantation for the treatment of haematological malignancies and other life threatening disorders of the haemopoietic stem cell is universally accepted. In contrast, the use of adult marrow derived stem cells for tissue repair strategies in degenerative disease or after tissue damage are only in the early stages of evolution. A range of opinion exists within the general public and the scientific community about whether research with human embryonic stem cells is ethically acceptable. Further, the current paucity of human embryonic stem cell data has lead investigators to consider adult marrow as a potential source of stem cells to treat a wide range of degenerative disease and damaged tissues. Target disorders include osteoarthritis, diabetes mellitus, Parkinson's disease, ischaemic heart disease and retinal degeneration. Obvious advantages of this approach, if successful, would be fewer ethical hurdles compared with embryonic stem cells. Treatment with the patients own marrow stem cells would eliminate the possibility of allogeneic rejection.