PCL retained is safe in medial pivot TKA-a prospective randomized trial

PURPOSE

Medial pivot (MP) designs resemble native knee kinematics and restore the "natural" kinematics of a knee after total knee arthroplasty (TKA). However, whether to preserve or resect the posterior cruciate ligament (PCL) is still under debate. We inquired whether sacrificing the PCL would improve range of motion, functional outcomes, and limb alignment compared to preserving the PCL in TKA using medial pivot implants (MP-TKA).

METHODS

This prospective, double-blinded, randomized controlled trial consisted of 33 patients (66 knees) undergoing bilateral simultaneous MP-TKA. In one knee, a PCL preservation technique was performed, and in the contralateral knee, the PCL was resected. The primary outcome was postoperative range of motion (ROM). The secondary outcomes were visual analogue scale (VAS) score for knee pain at walking, Knee Injury and Osteoarthritis Outcome Score for symptoms (KOOS-S) and quality of life (KOOS-QoL), Oxford knee score (OKS), and Forgotten Joint Score (FJS), and measurement of the mechanical femoral-tibial axis (mFTA) on X-ray images. All patients were followed up for a minimum of 2 years after surgery.

RESULTS

Patients who underwent MP-TKA with PCL preservation had a similar ROM at 2 years (125.45 ± 7.00 vs. 126.21 ± 6.73, p = 0.65) as those who underwent MP-TKAs with PCL resection. There was also no difference in VAS score (1.94 ± 0.79 vs. 2.00 ± 0.71, respectively, p = 0.51), OKS (39.97 ± 2.01 vs. 39.67 ± 2.03, respectively, p = 0.52), KOOS-S (84.41 ± 3.77 vs. 84.19 ± 3.57, respectively, p = 0.92), KOOS-QoL (82.94 ± 4.76 vs. 82.75 ± 4.70, respectively, p = 0.84), or FJS (72.66 ± 8.99 vs. 72.35 ± 8.64, respectively, p = 0.76) at the 2-year follow-up. No difference in the measurement of the mFTA was found between the two groups (180.27 ± 2.25 vs. 181.30 ± 2.13, respectively, p = 0.59).

CONCLUSION

This study demonstrated that both medial pivot TKA with PCL preservation and PCL resection achieved excellent results. There was no difference at the 2-year follow-up in terms of postoperative ROM, patient-reported outcomes, or radiographic evaluation.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Extended trochanteric osteotomy is a safe procedure in two-stage hip revision: a systematic review of the literature

BACKGROUND

Extended trochanteric osteotomy (ETO) has proved to be an effective technique in complicated stem removal in femoral aseptic loosening or periprosthetic fracture. Debate remains about its safety in periprosthetic joint infection (PJI). The primary aim of this study is to analyze the ETO reinfection and union rate in two-stage hip revision.

MATERIAL AND METHODS

A systematic literature review was performed regarding all studies reporting ETO outcomes in the two-stage revision for hip PJI up to October 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. A literature search was conducted in the following databases: MEDLINE/EMBASE, Scopus, Web of Science, and Cochrane. Quality assessment of the articles was performed using the Methodological Index for Non-Randomized Studies. This systematic review was registered in the International Prospective Registry of Systematic Reviews. Patient demographic, clinical, and surgical data were collected.

RESULTS

This systematic review included and analyzed nine clinical studies with a total of 382 ETO PJI hips in two-stage revision. The overall ETO reinfection rate was 8.9% (34 hips), consistent with the reinfection rate after two-stage revision in patients without ETO. The overall ETO union rate was 94.8% (347 hips), comparable to the ETO union rate in non-septic patients. Compared between a group of patients with ETO PJI and a group of patients with non-PJI ETO, there were no significant differences in postoperative complications, both septic and aseptic, and for postoperative HHS.

CONCLUSION

ETO proved to be a safe and effective procedure in PJI revisions. It may be a viable option in challenging femoral stem removal during the two-stage hip revision in PJI.

LEVEL OF EVIDENCE

IV.

Characterizing recurrent infections after one-stage revision for periprosthetic joint infection of the knee: a systematic review of the literature

BACKGROUND

Periprosthetic joint infection (PJI) of the knee represents a severe complication after 1.5% to 2% of primary total knee replacement. Although two-stage revision was considered the gold-standard treatment for PJI of the knee, in the last decades, more studies reported the outcomes of one-stage revisions. This systematic review aims to assess reinfection rate, infection-free survival after reoperation for recurrent infection, and the microorganisms involved in both primary and recurrent infection.

MATERIAL AND METHODS

A systematic review of all studies reporting the outcome of one-stage revision for PJI of the knee up to September 2022, according to PRISMA criteria and AMSTAR2 guidelines, was performed. Patient demographics, clinical, surgical, and postoperative data were recorded.

PROSPERO ID

CRD42022362767.

RESULTS

Eighteen studies with a total of 881 one-stage revisions for PJI of the knee were analyzed. A reinfection rate of 12.2% after an average follow-up of 57.6 months was reported. The most frequent causative microorganism were gram-positive bacteria (71.1%), gram-negative bacteria (7.1%), and polymicrobial infections (8%). The average postoperative knee society score was 81.5, and the average postoperative knee function score was 74.2. The infection-free survival after treatment for recurrent infection was 92.1%. The causative microorganisms at reinfections differed significantly from the primary infection (gram-positive 44.4%, gram-negative 11.1%).

CONCLUSION

Patients who underwent a one-stage revision for PJI of the knee showed a reinfection rate lower or comparable to other surgical treatments as two-stage or DAIR (debridement, antibiotics, and implant retention). Reoperation for reinfection demonstrates a lower success compared to one-stage revision. Moreover, microbiology differs between primary infection and recurrent infection. Level of evidence Level IV.

Trabecular titanium cups in hip revision surgery: a systematic review of the literature

Background

Hip revision surgery in extensive acetabular bone defects represents a complex challenge for hip surgeons. The primary goal is to obtain a stable acetabular component and restore the hip biomechanics. Through the years, different prosthetic implants have been developed to perform acetabular revision depending on bone loss location and extension. This systematic review aims to summarize the clinical outcomes and complications reported with trabecular titanium (TT) cups in hip revision surgery.

Methods

A literature search of four databases (PubMed, Embase, Scopus and the Cochrane Database of systematic reviews) was performed according to the PRISMA guideline from January 2008 to December 2022. All studies written in English and reporting the clinical outcome of patients undergoing revision total hip arthroplasty using Delta TT cups were included. The initial screening identified 378 studies. Each eligible clinical article was analyzed according to the Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence (LoE), and the papers' methodological quality was evaluated using The Methodological Index for Non-Randomized Studies Criteria (MINORS) score.

Results

Eight clinical studies were included in the analysis. A total of 523 hip revisions were analyzed. Delta TT cups were used in 3.9%, Delta TT one cups in 46.8%, and Delta TT revisions in 49.3%. Paprosky IIIa was the most frequent acetabular bone defect reported in 26.4% of cases. The overall survival rate of TT cups was 93.4%. The dislocation was the most frequent complication in 4.1% of patients, while the prevalence of aseptic loosening was 1.5.

Conclusions

Managing severe acetabular bone defects remains a complex challenge for hip surgeons. Since their introduction, TT cups have exhibited good clinical results, with complication rates in line with or lower than those reported by similar implants.

Outcomes of modular stem for the treatment of periprosthetic femoral fracture: a systematic review of the literature

Background

Periprosthetic femoral fractures (PFFs) are a frequent complication after total hip arthroplasty (THA). Both modular and non-modular tapered fluted titanium (TFT) stems could be used in total hip revisions (THRs). Nevertheless, the most appropriate femoral stem type is still under debate. The current systematic review aims to analyze the survival rate and all causes of stem revision, the overall complication rate and reason for reoperation, and patient reported outcome measures (PROMs) in THR for PFF using the modular tapered titanium stems (MTTS).

Methods

A comprehensive search in four databases, PubMed, Scopus, Embase, and the Cochrane Database of Systematic Reviews databases, was performed, and following the PRISMA guidelines, a systematic review was conducted. Strict inclusion and exclusion criteria were applied, starting from 1,259 studies. The risk of bias was analyzed according to the MINORS tool system. Descriptive statistical analysis was performed for all data extracted.

Results

Eighteen clinical studies were included in the qualitative analysis for a total of 775 patients enrolled. A mean MINORS criteria score of 9.8 [8-12] was reported. The overall survival of MTTS for PFF treatment was 95.4%, with an overall reintervention rate of 10.3% at an average follow-up of 4.5 years. Despite the use of modular components, postoperative hip instability remains the most frequent complication and cause of reintervention in these patients. In addition, a mean postoperative Harris Hip Score (HHS) of 78.1 was reported, which was considered acceptable given the high mean age of 74.1 years at the time of the revision.

Conclusions

Several therapeutic approaches and a wide variety of implants have been described in the literature for PFF management; however, no one solution has proven superior to others in the PFF treatment. MTTS has become a commonly used treatment option for Vancouver B2 and B3 fractures because they provide good clinical and radiological results with a reasonable survival rate. However, the complication rate of MTTS is still high.

Two-stage revision in periprosthetic joint infection of the hip using a new intraoperatively molded articulating spacer design

Purpose

The treatment of periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is still under debate. Two-stage exchange arthroplasty is the most common surgical procedure performed. This study analyzed a new functional articulating hip spacer called "Spaceflex" regarding the mechanical-related complications, the recurrent/persistent infection during the interval period, the overall infection-free survivorship after reimplantation, the overall complication/reoperation after reimplantation and the evaluation of patient-reported outcome measures (PROMs) at three intervals of time: before the first stage, during the interval period, and at the final follow-up after reimplantation.

Methods

A consecutive series of 56 patients with chronic hip PJI undergoing two-stage prosthetic revision using a new intraoperatively molded articulating hip spacer design implanted by the same experienced surgeons was examined from January 2017 to December 2021. The demographic and clinical characteristics of the included patients were analyzed. Specifically, PROMs before the first stage, during the interval period, and at the final follow-up after reimplantation and complications reported during the interval period and after reimplantation were examined.

Results

The new functional articulating hip spacer was characterized by a low mechanical complication rate (5.8%) and an overall two-stage procedure success rate of 90.6% at the last follow-up. PROMs improved with the spacer during the interval period and at the final follow-up. Furthermore, the reinfection rate was in line with other case series with different spacer designs. Finally, low postoperative complication rates after reimplantation have been demonstrated.

Conclusions

Two-stage revision performed with a modular articulating spacer allows patients to preserve satisfactory functional and quality-of-life outcomes in the postoperative period, with a low risk of mechanical complications and without increasing the reinfection rate.

How to Manage Metallosis: A Retrospective Cohort Analysis after Revision Hip Surgery

BACKGROUND

Adverse local tissue reactions to metal debris are due to a metal-on-metal bearing complication caused by micromotions at modular interfaces that induce corrosion of the protective oxide layer. This process could lead to wear, fretting, and abrasion with the release of metal ions locally and systemically, which may cause adverse local reactions in nearby tissues. The aim of this study is to describe a series of patients with painful local adverse tissue reactions secondary to corrosion at the modular neck-body interface, to document the clinical presentation, diagnostic workup, and surgical findings of our research, and to search for a possible correlation between metallosis and infection.

METHODS

A retrospective study of patients with adverse local tissue reactions due to metal surface corrosion was performed. Blood samples were collected to identify erythrocyte sedimentation rate, C reactive protein, and procalcitonin, and a magnetic resonance imaging protocol was performed.

RESULTS

Serum cobalt and chromium levels of the 43 patients tested were significantly higher on average. However, both erythrocyte sedimentation rate and C-reactive protein were significantly elevated. Magnetic resonance imaging showed adverse reactions to metal debris with large soft tissue masses and surrounding tissue damage.

CONCLUSIONS

Corrosion in hip prosthesis can lead to the release of metal ions and debris locally and systemically, resulting in local soft tissue changes. A "tumor-like" debridement can reduce this complication.

Predictive Value of the C-Reactive Protein to Albumin Ratio in 30-Day Mortality after Hip Fracture in Elderly Population: A Retrospective Observational Cohort Study

BACKGROUND

C-reactive protein (CRP) to Albumin ratio (CAR) has been used in multiple clinical settings to predict early mortality. However, there is a lack of evidence on the predictive role of CAR in 30-day mortality after a hip fracture. The purpose of this study was to establish a potential association between CAR and 30-day mortality and to assess if the CAR Receiving Operating Characteristics curve (ROC) can be a reliable predictor of early mortality.

METHODS

We retrospectively reviewed the charts of 676 patients (>65 years) treated for hip fracture between 2006 and 2018. All hip fractures were included. Treatment strategies included closed reduction and internal fixation, open reduction and internal fixation, hemiarthroplasty, or total joint arthroplasty. Statistical analysis included T-test, Pearson correlation for CAR and other markers, ROC curves and area under the curve, Youden Model, and Odds Ratio.

RESULTS

The 30-day mortality rate analysis showed that higher preoperative levels of CAR were associated with higher early mortality. When analyzing the area under the ROC curve (AUROC) for 30-day mortality, the reported value was 0.816. The point of the ROC curve corresponding to 14.72 was considered a cut-off with a specificity of 87% and a sensibility of 40.8%. When analyzing values higher than 14.72, the 30-day mortality rate was 17.9%, whilst, for values lower than 14.72, the 30-day mortality rate was 1.8%.

CONCLUSIONS

Patients older than 65 years affected by a hip fracture with increased preoperative levels of CAR are associated with higher 30-day mortality. Despite a moderate sensibility, considering the low cost and the predictivity of CAR, it should be considered a standard predictive marker.

Current Practice of Italian Association of Revision Surgery Members in the Treatment of Unified Classification System Type B Periprosthetic Femoral Fracture Around Hip Arthroplasty: A Cross-Sectional Survey

Introduction

Periprosthetic femoral fracture around hip arthroplasty are growing in the world, nevertheless management and treatment options for fractures “around the stem” are still debated due to lack of high-level studies.

Materials and method

A 85-item survey were fill out by 40 Italian Orthopedic Surgeon member of SIOT (Società Italiana di Ortopedia e Traumatologia) and AIR (Associazione Italiana Riprotesizzazione) to assess their current opinion in the management of type B periprosthetic femoral fractures. Responses were summarized using proportions, and further stratified by practice type, case volume, surgeon age, and fellowship training.

Results

Vancouver/UCS fracture classification showed a good interobserver agreement (k value = .76). ORIF were the treatment of choice for UCS type B1 fractures (100%), revision stem for B2 (85%) and B3 (100%). Locked plates were preferred to cable plate and cerclage without a plate for B1 fractures (50% vs 40% vs 10%); revision with modular stem was preferred to monoblock stem for B2 fractures (50% vs 35%) and B3 (75% vs 15%). Responders tended to postpone at 1-month weight-bearing in patients with B1 fractures. Regarding postoperative pharmacological treatment there was absolute lack of consensus.

Discussion

The primary finding of our survey confirmed the preference of ORIF for B1 fractures and stem revision for B2 and B3 fractures. However, there is no definitive operative technique for all UCS B fractures. Surgeons tended to favor locked plating over cable plating, although only slightly. This general lack of consensus coincides with the inconclusive evidence that currently exists in the literature, which demonstrates both favorable and unfavorable outcomes for both techniques

Conclusions

The absence of complete homogeneity among participants showed the need for prospective randomized studies to set up stronger guidelines for classification, management, surgical treatment, rehabilitation, and pharmacological support of periprosthetic femoral fractures.

Measures for co-medicals in postwar Okinawa: scarcity of the personnel for allocating vaccinations

Background

The shortage of doctors in postwar Okinawa has led to the creation of co-medicals. They were called medical service personnel and authorized to handle certain medical treatments. This included tasks such as providing injections and vaccinations under the supervision of the doctor in the health center.

Issue/problem

The system of co-medicals only applied in Okinawa and not in Japan. As such, when Okinawa was reverted back to Japan in 1972, it was proposed to abolish the system. In the current emergency of the new coronavirus pandemic, we are facing a similar situation in terms of the shortage of medical personnel.

Description of the problem

In Japan, like many countries, there is a shortage of health resources due to the COVID-19 pandemic. The focus will be on healthcare personnel, those who have taken on the role of COVID-19 vaccinators in Japan, and a comparison of the situation in other countries.

Results

In Japan, vaccinations are legally limited to being administered by doctors and nurses. However, pharmacists have taken on the role of administering vaccinations in the UK, US, Ireland, Canada, and Italy, thus COVID-19 vaccinations could be easily integrated into these routine procedures.Even vaccinations by medical students have been carried out. In addition, non-healthcare volunteers have been trained as vaccinators in UK and Italy. The coverage has reached 50% in the UK, 42% in the US, and 30% in Canada, whereas 1.8% in Japan in April (Our World in Data, 2021).

Lessons

Although the COVID-19 situation is substantially different from the case of postwar Okinawa, it will be necessary to take resilient measures to solve the medical personnel shortage. Additionally, the strict measures of limiting vaccinations by medical doctors may need to be reconsidered in Japan. Establishing a system of allowing co-medicals to have a shared role could offer innumerable benefits for all.

Key messages

Expanding the task of vaccinations to co-medicals has had beneficial results in several countries. Dividing roles of medical doctor need to be considered.

Current Reconstruction Options in Periprosthetic Fractures Around the Knee

Background:

Periprosthetic fractures are a rare complication after total knee arthroplasty (TKA). However, the incidence of these fractures is growing after the increasing number of TKAs performed every year and the progressive aging of the population. In addition, the surgical treatment and peri-operative management of these complications are demanding, representing a challenge for the orthopedic surgeon.

Significance:

A thorough understanding of these fractures and a correct classification are necessary in order to select the most suitable surgical treatment. The aim of this review was to analyze the epidemiology, classification, diagnosis, surgical treatment, and outcomes of periprosthetic knee fractures in order to give an exhaustive overview.

Results:

Reduction and internal fixation with locking plates or intramedullary nails represents the preferred option in case of a stable prosthetic implant. Conversely, in case of loose tibial and/or femoral component, implant revision is mandatory. Conservative treatment is rarely indicated.

Conclusion:

A deep understanding of the characteristics and patterns of periprosthetic knee fractures, and the determination of the stability of the prosthetic implant are necessary in order to establish the correct treatment.

Mid-term survivorship and clinical outcomes of the medial stabilized systems in primary total knee arthroplasty: A systematic review

Introduction

Medial Pivot Total Knee Arthroplasty was introduced in clinical practice in 1990s to reproduce the in vivo-natural knee kinematics. This design is characterized by an asymmetric constraint profile, with aa highly congruent medial compartment, and a less congruent lateral compartment. Short-term outcomes of the medial pivot systems in primary knee arthroplasty have been widely reported in the current literature, however, only few studies have described results beyond 5-year follow-up.

Objectives

The primary objectives of this systematic review of the literature is to analyze the mid-term studies on medial pivot total knee arthroplasty focusing on the reoperation rate, survivorship and clinical outcome scores.

Methods

The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications from January 1980 to December 2019 utilizing the following keywords: "medial pivot", "medial stabilized", "medial rotating", "medial congruent", medial ball and socket", "arthroplasty", "TKA", "TKR", and "knee surgery".

Results

18 articles met the inclusion criteria for the present study. The average quality was 11.4 for non-comparative studies and 21.7 for comparative studies based on MINORS criteria. A total 2832 knee arthroplasties were included for the final analysis with an average age of 69 years, and an average follow-up of 8.1 years (minimum 5 years). The overall reoperation rate was 2.4%, with periprosthetic joint infection as the leading cause of revision in 0.9% of cases, followed by aseptic loosening in 0.4% of cases. The average Knee Society Score improved to a mean preoperative score of 40.1 to a mean postoperative score of 89.2. The functional knee society score improved from a mean preoperative score of 44.8 to an average postoperative score of 82.9. The global range of motion improved from 104.8° preoperatively to 115.6° postoperatively.

Conclusion

We found that medial pivot system in primary total knee arthroplasty provide overall mid-term survivorship comparable to other standard implasnts. In addition, medial pivot system is associated with better high-end function compared to standard implants.

Does negative pressure intrusion cementing technique improve the cement penetration under the tibial component? A comparative retrospective study

Intramedullary suction cementing technique of the tibial component has the theoretical advantage to allow a deeper cement penetration trough the cancellous bone. The aim of this study is to compare the cement penetration under the tibial component between patients that underwent tibial component cementation with or without the use of intramedullary suction. Two-hundred-twenty-four patients underwent primary total knee arthroplasty (TKA) during the study period, One-hundred-twenty-two TKAs using intramedullary suction with negative pressure (55.4%), while one-hundred-two TKAs without intramedullary suction (44.6%). We found that the intra-operative suction during cement application increase the depth of cement penetration better than pulsed lavage alone.

Mechanical and elution properties of G3 Low Viscosity bone cement loaded up to three antibiotics

OBJECTIVE

Periprosthetic Joint Infection (PjI) is considered one of the most difficult complication to manage after total knee or hip arthroplasty, with a mean incidence of 1%. Antibiotic loaded bone cement is used as prophylaxis during primary arthroplasty and as local therapy during two-stage revision. The aim of this study is to evaluate the mechanical and elution properties of G3 Low Viscosity Bone Cement (G-21 San Possidonio, Modena, Italy) loaded with different doses of up to three antibiotics (12 specimens).

METHODS

Compressive Strength, Bending Strength and Bending Modulus were evaluated. Cumulative Vancomycin elution by adding different doses of antibiotics was evaluated.

RESULTS

The mean Compressive Strength was 81.55 MPa, the mean Bending Strength was 2161.7 MPa, and the mean Bending Modulus was 36.6 MPa. The highest cumulative Vancomycin elution was observed in specimen 12 (1906.9 mg at 2 weeks). This is the first study, at our knowledge, that analysed how cement mechanical properties, and antibiotic elution kinetics, are modified by adding up to three antibiotic.

CONCLUSION

The results obtained in this pilot study using G3 Low-Viscosity Bone Cement, demonstrated that mechanical properties not decrease significantly by adding large doses of antibiotics, while the Vancomycin elution increase until swelled to twice.

Trabecular Titanium acetabular cups in hip revision surgery: mid-term clinical and radiological outcomes

INTRODUCTION:

Severe acetabular bone loss during revision hip arthroplasty can be restored with different surgical techniques. Best results have been observed using porous tantalum cementless cups. Trabecular Titanium (TT) cups were designed to reproduce the structure, mechanical and biological characteristics of trabecular bone. Few clinical studies have been published with these cups. The aim of this study is to evaluate the clinical and radiological outcome of patients with large acetabular defects (Paprosky IIb or higher) revised using TT cups.

MATERIALS AND METHODS:

64 consecutive patients who underwent revision for total hip arthroplasty (THA) between 2011 and 2015 at our institution were enrolled. All were classified as Paprosky IIb, IIc, IIIa and IIIb. Periprosthetic joint infections and fractures were not included in this study. Radiographic and clinical (Harris Hip Score (HHS)) outcomes were evaluated. Kaplan-Meyer survivorship curve was performed.

RESULTS:

Complete data of 58 patients (mean follow-up 48.3 months) were analysed. 6 patients underwent a further revision (10.3%). Causes of re-revision were instability (5.2%), infection (3.4%) and aseptic loosening (1.7%). No radiolucent lines or signs of migration were observed. Survivorship was 94.8%. HHS Improved from a mean of 36.5-83.7.

DISCUSSION:

TT cups demonstrated encouraging results at mid-term follow-up. Cup modularity represented a helpful tool to restore hip rotation centre and to reduce the risk of dislocation. The capacity of trabecular titanium to induce bone growth and the versatility of modularity, make the Delta TT System a very useful aid for surgeons who are more frequently faced with complex revision.

Electron backscattered diffraction analysis of friction stir processed nanocomposites produced via spark plasma sintering

In the present study, Spark Plasma Sintered (SPSed) aluminium matrix composites were severely deformed through Friction stir processing (FSP). Pure aluminium powders and bimodal sized Al2 O3 particles (80 nm and 25 μm) were firstly mixed by ball milling and then consolidated by spark plasma sintering. The effect of the heat input as well the bimodal particle size of the alumina on the materials' microstructure and texture development was evaluated by electron back scattered diffraction (EBSD) analysis. The EBSD analysis clearly showed that the SPSed nanocomposites possessed bimodal aluminium matrix grain structure as well as a crystallography characterised by random texture. In addition, microstructural examination revealed that the partial recrystallisation occurred during SPS for all the nanocomposites. Also, it is revealed that the Zener pinning effect of Al2 O3 nanoparticles retarded recrystallised grain growth following recrystallisation during FSP and then leading to grain refinement of the aluminium. The results revealed that the heat generated during FSP has a remarkable effect on the grain distribution as well as on the crystallographic orientation. Also, a mixture of {112} <110> shear elements and an ideal strong B/B¯ component were observed. The microstructural changes, occurred during FSP in the stir zone region for Al-Al2 O3 nanocomposites, were attributed to both the discontinuous along with the continuous recrystallisation (DDRX/CDRX). It should be pointed out that with increasing the heat input, recrystallised grains portion increased.

Anatomical differences in the bony structure of L5 and L4: A possible classification according to the lateral tilt of the pedicles

The aim of this study is to underline the necessity of a better knowledge of pedicles anatomy in order to improve surgical treatment of spine disorders such us low back pain, spinal fractures and scholiosis. A classification of pedicles lateral tilt which could help surgeons before the application of screws during transpedicular fixation is reported. Anatomical differences in the orientiation of the pedicles of L5 and L4 have been found. For each patient that met the inclusion criteria underwent: Radiography of the lumbo-sacral region, CT examination, MRI acquisition. Patients were divided into three categories thanks to 3D direct volume rendering of CT scan. Subjects belonged to W-Type, V-Type and U-type depending on their morphometric features. The subdivision was further implemented with measurements of the distance between pedicles and adjacent nervous structures. Concerning L5, W-Type (WT) exhibited a lateral tilt of L5 larger than 36°, V-Type exhibited a lateral tilt of L5 from 30° to 36°, U-type exhibited a lateral tilt of L5 smaller than 30°. Concerning L4, WT exhibited a lateral tilt of 28.4°, VT exhibited a lateral tilt of of 25.1, UT exhibited a lateral tilt of 22.2°; we assume that the degree of lateralization of L4 depends on the one of L5. The way the screw is applied during surgical treatment is clinically relevant, thus our classification may be very useful in order to decrease surgical risk and improve conditions of patients after surgical treatment.

Anandamide and diet: inclusion of dietary arachidonate and docosahexaenoate leads to increased brain levels of the corresponding N-acylethanolamines in piglets

Endogenous ligands of cannabinoid receptors have been discovered recently and include some N-acylethanolamines (NAEs; e.g., N-arachidonoylethanolamine) and some 2-acylglycerols (e.g., sn-2-arachidonoylglycerol). Previously, we found these compounds to be active biologically when administered per os in large quantities to mice. In the present work, piglets were fed diets with and without 20:4n-6 and 22:6n-3 fatty acid precursors of NAEs, in levels similar to those found in porcine milk, during the first 18 days of life, and corresponding brain NAEs were assessed. In piglets fed diets containing 20:4n-6 and 22:6n-3, there were increases in several biologically active NAEs in brain homogenates-20:4n-6 NAE (4-fold), 20:5n-3 NAE (5-fold), and 22:5n-3 and 22:6n-3 NAE (9- to 10-fold). These results support a mechanism we propose for dietary long-chain polyunsaturated fatty acids influences on brain biochemistry with presumed functional sequelae. This paradigm will enable targeted investigations to determine whether and why specific populations such as infants, elderly, or persons suffering from certain clinical conditions may benefit from dietary long-chain polyunsaturated fatty acids.

Enhancement of anandamide formation in the limbic forebrain and reduction of endocannabinoid contents in the striatum of delta9-tetrahydrocannabinol-tolerant rats

Recent studies have shown that the pharmacological tolerance observed after prolonged exposure to synthetic or plant-derived cannabinoids in adult rats is accompanied by down-regulation/desensitization of brain cannabinoid receptors. However, no evidence exists on possible changes in the contents of the endogenous ligands of cannabinoid receptors in the brain of cannabinoid-tolerant rats. The present study was designed to elucidate this possibility by measuring, by means of isotope dilution gas chromatography/mass spectrometry, the contents of both anandamide (arachidonoylethanolamide; AEA) and its biosynthetic precursor, N-arachidonoylphosphatidylethanolamine (NArPE), and 2-arachidonoylglycerol (2-AG) in several brain regions of adult male rats treated daily with delta9-tetrahydrocannabinol (delta9-THC) for a period of 8 days. The areas analyzed included cerebellum, striatum, limbic forebrain, hippocampus, cerebral cortex, and brainstem. The same regions were also analyzed for cannabinoid receptor binding and WIN-55,212-2-stimulated guanylyl-5'-O-(gamma-[35S]thio)-triphosphate ([35S]GTPgammaS) binding to test the development of the well known down-regulation/desensitization phenomenon. Results were as follows: As expected, cannabinoid receptor binding and WIN-55,212-2-stimulated [35S]GTPgammaS binding decreased in most of the brain areas of delta9-THC-tolerant rats. The only region exhibiting no changes in both parameters was the limbic forebrain. This same region exhibited a marked (almost fourfold) increase in the content of AEA after 8 days of delta9-THC treatment. By contrast, the striatum exhibited a decrease in AEA contents, whereas no changes were found in the brainstem, hippocampus, cerebellum, or cerebral cortex. The increase in AEA contents observed in the limbic forebrain was accompanied by a tendency of NArPE levels to decrease, whereas in the striatum, no significant change in NArPE contents was found. The contents of 2-AG were unchanged in brain regions from delta9-THC-tolerant rats, except for the striatum where they dropped significantly. In summary, the present results show that prolonged activation of cannabinoid receptors leads to decreased endocannabinoid contents and signaling in the striatum and to increased AEA formation in the limbic forebrain. The pathophysiological implications of these findings are discussed in view of the proposed roles of endocannabinoids in the control of motor behavior and emotional states.

New scalaranes from the nudibranch Glossodoris atromarginata and its sponge prey

Two new scalaranes (1 and 2) have been isolated from the dorid nudibranch Glossodoris atromarginataand its prey. The structures were deteremined by spectral techniques and confirmed by chemical methods. Compounds 1 and 3 showed selective cytotoxic activity against human thyroid carcinoma.

[Acute pancreatitis: case reports from 1992-1997. Analysis of the costs of DRG, role of ERCP in the reduction of hospitalization time]

In the period 1992-1997, 211 cases of acute pancreatitis were observed: 81 grave cases; 130 slight cases. The ERCP and endoscopic sphincterotomy were performed in 84 cases. From the critical revision 2 groups of patients emerged, homogeneous for etiology and clinical classification, the first submitted to ERCP within 72 hours from the entry in hospital; the other after 72 from the hospitalisation. The "t" Students test for small numbers was significant (p < 001) showing a decrease of hospitalisation in the submitted group to ERCP within 3 days. In 42 cases of acute pancreatitis observed in 1997 a study was made about the hospitalised patients' costs. Two homogeneous groups of acute and slight pancreatitis have been considered. The parameters analysed were about the costs of: a) days hospitalisations; b) pharmaceutical expenses; c) hematological examination; d) surgical operation, laparothomic and laparoscopic surgery; e) instrumental examination. The results of the expense have been compared with the obtained DRG, both for each single case and also for homogeneous group of grave and slight pancreatitis. This comparison showed that the obtained gain through DRG is: a) insufficient to cover the expenses of the grave pancreatitis cases; b) clearly positive in the slight cases. This last result has been very important in the final balance; in fact is only for this positive result that final balance was economically favourable.

[Incidence of wheezing asthma, rhinitis, urticaria and conjunctivitis in a pediatric emergency department]

The Authors considered the incidences of the urgencies for allergic pathology arrived at Santobon Hospital during January-December 1992. In the period of twelve months a whole of 42.702 children came to Hospital; among them 4.359 showed an allergic pathology with a clear prevalence for wheezing and asthma. In addition it was observed too that an allergic mainly affected male children.

Dielectric receivers for asymmetrical ideal concentrators

Cylindrical asymmetrical nonimaging concentrators with receivers based on tin absorbers immersed in dielectric rhombuses are introduced and shown to be ideal. They have the same concentration factor as dielectric filled devices but require only a small amount of dielectric around the absorber. The asymmetric shape and nontracking property of the collectors allow their arrangement in flat panels that, integrated with a supporting thermal insulator, may be the roof or the wall of a small building situated in a remote locality. This would passively satisfy the electric requirements of the building.

Lengthening of the lower limbs and correction of lumbar hyperlordosis in achondroplasia

This paper describes the technical development as well as results obtained with the method of bone lengthening developed by the author and used over the past fifteen years for the treatment of short-statured conditions not susceptible to hormonal treatment.

Ideal nonfocusing concentrator with fin absorbers in dielectric rhombuses

Two ideal concentrators with fin absorbers in dielectric rhombuses are described. Expressions for the design, height, and mirror length are derived. The devices have a concentration factor (n/sin ?(M)) that is clearly higher than the traditional air-filled ideal concentrators. They do not require more mirrors or space and, when such easily available dielectrics as glass and water are used, offer useful configurations for purposes such as the collection of solar energy.