Gamma radiation sterilization can make cortical bone allograft more brittle, but whether it influences mechanical properties and propensity to form microscopic cracks in structurally intact cancellous bone allograft is unknown.
Questions/purposes
We therefore determined the effects of gamma radiation sterilization on structurally intact cancellous bone mechanical properties and damage formation in both low- and high-density femoral cancellous bone (volume fraction 9%–44%).
Methods
We studied 26 cancellous bone cores from the proximal and distal femurs of 10 human female cadavers (49–82 years of age) submitted to a single compressive load beyond yield. Mechanical properties and the formation of microscopic cracks and other tissue damage (identified through fluorochrome staining) were compared between irradiated and control specimens.
Results
We observed no alterations in mechanical properties with gamma radiation sterilization after taking into account variation in specimen porosity. No differences in microscopic tissue damage were observed between the groups.
Conclusions
Although gamma radiation sterilization influences the mechanical properties and failure processes in cortical bone, it does not appear to influence the performance of cancellous bone under uniaxial loading.
Clinical Relevance
Our observations support the use of radiation sterilization on structurally intact cancellous bone allograft.
The present study was designed to ascertain how altered biomechanics in adolescent idiopathic scoliotic (AIS) intervertebral discs (IVDs) affected tissue compositions and aggrecan processing compared to age matched and aged human IVDs. Newborn, 2- and 10-year-old ovine IVDs were also examined.
Methods
Aggrecan populations were separated by Sepharose CL2B chromatography, composite agarose polyacrylamide gel electrophoresis (CAPAGE) and identified by immunoblotting. The KS and CS content of IVD tissue extracts from AIS IVDs were compared with age-matched normal adolescent IVDs and with old human IVDs. Extracts from newborn, 2- and 10-year-old ovine IVDs were also examined in a similar manner.
Results
Adolescent idiopathic scoliotic IVD Aggrecan populations shared similar levels of polydispersity and aggregatability with hyaluronan as old IVD proteoglycans. CAPAGE demonstrated three aggrecan populations in AIS, aged human and ovine IVDs increased polydispersity and mobility in CAPAGE. AIS IVDs had GAG compositions similar to aged human and ovine IVDs. Sulphated KS (5-D-4) and chondroitin-6-sulphate, 3-B-3(+) were markers of tissue maturation, and chondroitin-4-sulphate, 2-B-6(+) was prominent in immature IVDs but its levels were lower in mature IVDs.
Discussion
Sulphated KS and 3-B-3(+) CS were prominently associated with IVD maturation and AIS IVDs, while the 2-B-6(+) CS isomer was associated with immature IVD tissues. The polydispersity of aggrecan in AIS IVDs, which was similar to in old human and ovine IVDs, reflected altered processing in the AIS IVDs in response to the biomechanical microenvironments the disc cells were exposed to in AIS IVDs.
Graphical abstract
These slides can be retrieved under Electronic Supplementary Material.
The purpose of this study was to assess changes in the three-dimensional (3D) load-bearing mechanical axis (LBMA) preoperatively and at 3 weeks and more than 1-year follow-up after total knee arthroplasty (TKA), and effects of the degree of constraint in the anteroposterior (AP) direction because of the retention of the posterior cruciate ligament (PCL) and the implant design on the changes in LBMA.
Methods
We evaluated 157 knees from 131 patients, including 79 knees that received meniscal-bearing-type (PCL-retaining) and 78 knees that received rotating-platform-type (PCL-substituting) prostheses. Quantitative 3D computed tomography was used to assess changes in the location of the pre- and postoperative LBMA at the tibial plateau level.
Results
Changes in the 3D axis were mainly found from medial to lateral and posterior to anterior in both implant designs with no significant differences. Change in the mediolateral (ML) direction was improved soon after TKA, but change in the AP direction improved more gradually over time. The different constraints in the AP direction because of the retention of the PCL and different implant designs did not affect the changes in the LBMA.
Conclusions
The LBMA in the AP direction more than 1 year postoperatively, as well as the LBMA in the ML direction at 3 weeks, appears to shift toward the location found in normal knees after TKA, regardless of the type of prosthetic constraint. These changes may be an important factor that influences the periarticular knee bone mineral density which load bearing may be related to.
The purpose of this study was stimation of optimal percentage of lateral uncoverage of the acetabular component during total hip arthroplasty for patients with severe developmental hip dysplasia.
Methods
Mathematical computer modeling based on the finite element technique and the mechanical experiment were performed. Critical values of uncoverage enabling safe primary fixation of acetabular component were estimated in designed models.
Results
Using the finite element technique and the mechanical experiment on pelvis models, a possibility of mounting an acetabular component with moderate uncoverage within 25% without screws and with significant uncoverage to 35% with an additional two-screw fixation was demonstrated.
Conclusions
This study provides additional guidance on optimal acetabular uncoverage assessment and fixation methods of surgeons performing THA on patients with DDH.
To determine the prevalence of microalbuminuria and associated factors among Congolese human immunodeficiency virus (HIV)-infected children.
Methods
This was a cross-sectional study in which 77 HIV-infected antiretroviral therapy-naive children and 89 uninfected controls were enrolled. Microalbuminuria was assessed using the immune-turbidimetry method, and associated factors were studied by logistic regression.
Results/Conclusion
The prevalence of microalbuminuria was 18% in the HIV-infected children and 2% in the HIV-uninfected children. No common determinants of proteinuria were significantly associated with microalbuminuria.
To analyse the prevalences of the cam and pincer morphologies in a cohort of patients with groin pain syndrome caused by inguinal pathologies.
Materials and methods
Forty-four patients (40 men and 4 women) who suffered from groin pain syndrome were enrolled in the study. All the patients were radiographically and clinically evaluated following a standardised protocol established by the First Groin Pain Syndrome Italian Consensus Conference on Terminology, Clinical Evaluation and Imaging Assessment in Groin Pain in Athlete. Subsequently, all of the subjects underwent a laparoscopic repair of the posterior inguinal wall.
Results
The study demonstrated an association between the cam morphology and inguinal pathologies in 88.6% of the cases (39 subjects). This relationship may be explained by noting that the cam morphology leads to biomechanical stress at the posterior inguinal wall level.
Conclusions
Athletic subjects who present the cam morphology may be considered a population at risk of developing inguinal pathologies.
Partial fundoplications have been popularized by their lower risk of mechanical side effects. The question then emerges whether a similar partial wrap should be done posterior or anterior to the distal esophagus? We therefore conducted a study to compare the long-term outcome of laparoscopic partial fundoplications constructed either as anterior (AF) or posterior (PF) repairs.
Patients and Methods
Ninety-five patients were enrolled in a randomized clinical trial. After a mean follow up of 65 months, 43 AF and 45 PF patients remained in the study. The levels of reflux control and postfundoplication complaints were assessed by use of validated instruments.
Results
A posterior fundoplication was found to provide significantly better control of reflux related symptoms (heartburn p < 0.0001, acid regurgitation p < 0.0001). This was also reflected in a significantly lower number of reoperations and need for antisecretory drug therapy. The earlier postoperative difference in postfundoplication symptoms had disappeared.
Conclusions
A laparoscopic posterior partial fundoplication offers a high and durable level of disease control with few side effects. The current anterior type of repair cannot be recommended due to insufficient reflux control.
Gas sterilization (eg, ethylene oxide [EtO] and gas plasma) was introduced for polyethylene to reduce oxidation due to free radicals occurring during radiation sterilization. Recently, oxidation has been observed in polyethylenes with undetectable levels of free radicals, which were expected to be oxidatively stable. It is unclear whether in vivo oxidation will occur in unirradiated inserts sterilized with EtO.
Questions/purposes
Methods
We collected 20 EtO-sterilized tibial inserts at revision surgeries. We assessed oxidative using Fourier transform infrared spectroscopy and mechanical properties using the small punch test. Surface damage was assessed using damage scoring techniques and micro-CT.
Results
Oxidation indexes were low and uniform between the regions. The subtle changes did not affect the mechanical properties of the polymer. The dominant surface damage modes included burnishing, abrasion, and third-body wear. There was no evidence of delamination in the retrievals.
Conclusions
The retrieved EtO-sterilized UHMWPE retrievals remained stable with respect to both oxidative and mechanical properties for up to 10 years in vivo. We did observe slight measurable amounts of oxidation in the inserts; however, it was far below levels that would be expected to compromise the strength of the polymer.
Clinical Relevance
Due to the stable oxidative and mechanical properties, EtO-sterilized tibial components appear to be an effective alternative to gamma-sterilized inserts, at least in short-term implantations.
To investigate the surgical outcomes of surgery for non-small cell lung cancer (NSCLC) in patients with atrial fibrillation (AF) as a preoperative comorbidity.
Methods
Among 805 patients who underwent surgery for NSCLC, 27 (3.4%) had a history of AF. We analyzed the perioperative and long-term outcomes of these 27 patients.
Results
Fourteen patients (52%) had chronic AF and 13 (48%) had paroxysmal AF; being high rates of a comorbid illness. Nineteen patients (70%) underwent lobectomy, and 8 (30%) underwent sublobar resection. Ten patients (37%) received perioperative heparinization. There was no mortality. Other non-AF postoperative complications developed in 8 patients (30%), this incidence being higher than among the patients without AF (16%, 127 out of 778, p = 0.09). A thromboembolic event occurred in one patient (4%). With respect to the long-term outcomes, the 5-year overall survival and disease-free survival rates among the patients with AF were 70.3 and 60.8%, respectively, which were similar to those in the patients without AF (79.8 and 72.6%, p = 0.30 and 0.31).
Conclusions
Lung cancer surgery in patients with AF is safe and provides favorable long-term outcomes; however, thoracic surgeons should monitor these patients carefully for postoperative thromboembolic events.
To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP).
Methods
T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level.
Results
With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1–3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level.
Conclusion
alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.
To evaluate the influence of osteoporosis on the microarchitecture and vascularization of the endplate in rhesus monkeys with or without intervertebral disc (IVD) degeneration using micro-computerized tomography (micro-CT), and to further analyze the correlation between osteoporosis and IVD degeneration.
Methods
Twelve rhesus monkeys were randomly divided into the ovariectomy (OVX, n = 6) and the sham group (n = 6). The subchondral bone adjacent to the lumbar IVDs (from L4/5 to L6/7) of each monkey was randomly injected with 4 ml pingyangmycin (PYM) solution (1.5 mg/ml, PYM), or 4 ml phosphate buffered saline (PBS) as vehicle treatment, or exteriorized but not injected anything as control (Cntrl). Degenerative and osteoporotic processes were evaluated at different time points. Micro-CT and histology were performed to analyze microarchitecture, calcification area and vascularization of the endplate.
Results
OVX resulted in significant decrease of bone mineral density (BMD). PYM injection induced progressively IVD degeneration, which was more progressive when combined with OVX. There was a negative correlation between BMD and Pfirrmann grade in the subgroups with PYM injection. The micro-CT analysis showed the combination of osteoporosis and IVD degeneration led to more calcification of endplate than any one thereof. The decrease of vascular volume percent in the endplate of the OVX-PYM subgroup was significantly greater than that in the Sham-PYM subgroup, both of which showed significant less vascularization compared to the other subgroups.
Conclusion
In conclusion the osteoporosis could accumulate the calcification and decrease the vascularization in the endplates adjacent to the degenerated IVDs, which subsequently exacerbated degeneration of the degenerated IVDs.
New patients come more and more often over the internet; therefore internet marketing plays an increasingly important role.
Question
How can physicians build an effective internet marketing strategy and avoid complications?
Method
Selection and authorization of a reputable agency.
Results
New customer acquisition through high visibility in the internet, at the same time increasing the image and awareness.
Conclusions
In the overall “marketing mix” internet marketing has become indispensable to physicians who want to be successful. Those who are well positioned in Google are well known by their target audience and thus receive a higher response.
Valve thrombosis – either biological or mechanical – is proved to increase patient’s morbidity and mortality. No consensus exist on the best management in such cases.
Case presentation
We report the case of a 69-year-old man presenting with a late thrombosis of a transcatheter aortic valve who was medically managed until he acutely worsened, developing myocardial ischemia and cardiogenic shock.
Conclusion
This unlucky case raises a word of caution about the safety of a reactive management.
Atrial fibrillation (AF) is a bi-atrial disease yet little attention has been given to right heart function in AF. We propose that the assessment of right atrial (RA) and right ventricular function (RV) using two-dimensional speckle tracking echocardiography (2D-STE) could be valuable in predicting AF recurrence in patients with paroxysmal AF (PAF).
Methods
Thirty patients with PAF were prospectively recruited from a dedicated AF clinic. Right atrial size, volume, and area and RV dimensions were analyzed along with RA and RV strain derived from 2D-STE at baseline and at 3 and 12 months.
Results
Higher RA booster strain independently predicted sinus rhythm (SR) maintenance for up to 1 year (P = 0.001). RV strain was impaired in patients with recurrent AF compared to those in SR (P < 0.05) but did not predict AF recurrence. Two-dimensional STE for RA and RV function was simple to perform with excellent reproducibility (adjusted R2 0.92–0.99).
Conclusions
Two-dimensional STE is useful and highly reproducible in assessing right heart function in AF patients. RA booster strain function was predictive of sinus rhythm maintenance for up to 1 year.
Radiofrequency ablation (RFA) and percutaneous vertebroplasty (PVP) are used independently and in combination to treat metastatically involved vertebrae with the aim of relieving pain, reducing tumour burden and providing bony mechanical stabilization.
Purpose
The aim of this work was to characterize the effect of two bone-targeted RFA devices, alone and in combination with PVP, to improve strength and mechanical stability in vertebrae with osteolytic metastatic disease.
Methods
Simulated spinal metastases (n = 12) were treated with one of two bone-targeted RFA devices (bipolar cooled or bone coil RF electrodes), followed by PVP. Under axial compressive loading, spinal canal narrowing was measured in the intact specimen, after tumour simulation, post-RFA and post-PVP.
Results
RFA alone resulted in successful tumour shrinkage and cavitation, but further increased canal narrowing under loading. RFA combined with PVP significantly reduced posterior wall stability in samples where sufficient tumour shrinkage and cavitation were coupled with a pattern of cement deposition which extended to posterior vertebral body.
Conclusions
RFA combined with cement deposition in the posterior vertebral body demonstrates significantly more stable vertebrae under axial loading.
The purpose of this study is to clarify morphological changes of acetabular subchondral bone cyst after total hip arthroplasty for osteoarthritis secondary to developmental dysplasia of the hip.
Methods
Two hundred and sixty-one primary cementless total hip arthroplasties of 208 patients, 18 males, 190 females, were retrospectively reviewed. Morphological changes of subchondral bone cyst were evaluated by computed tomography (CT). The mean cross-sectional area of the cyst from CT scans at 3 months postoperatively and after 7–10 years (average 8.4 years) were compared.
Results
Acetabular subchondral bone cysts were found in 49.0% of all cases in preoperative CT scans. There was no cyst which was newly recognized in CT scan performed after postoperative 7–10 years. All the cross-sectional areas of the cysts evaluated in this study were reduced postoperatively.
Conclusions
This study revealed that acetabular subchondral bone cysts do not increase or expand after total hip arthroplasty and indicated that the longitudinal morphological change of acetabular bone cysts in patients of developmental dysplasia of the hip do not influence long-term implant fixation in total hip arthroplasty.
Although recent findings show that the routine use of mechanical resuscitation devices in out-of-hospital cardiac arrest showed no benefit, such devices have found widespread use by emergency services in recent years.
Method
Case report and review of the literature.
Objective
In the 2015 Guidelines for Resuscitation from the European Resuscitation Council (ERC), the use of mechanical resuscitation devices is only described for specific situations. Starting with a case report, we discuss possible meaningful scenarios for use, taking into consideration the current literature and resuscitation guidelines.
Renal dysfunction is recognized with increasing frequency among the noninfectious comorbidities associated with human immunodeficiency virus (HIV) infection. Urinary liver-type fatty acid-binding protein (L-FABP) has been shown to be a new biomarker to screen for not only tubulointerstitial damage but also kidney dysfunction.
Methods
We performed a cross-sectional study to determine the association between the urinary L-FABP and chronic kidney disease (CKD) among 77 HIV-infected Japanese patients by backward-stepwise multivariable logistic regression.
Results
The prevalence of individuals in the low risk was 80 %. Urinary L-FABP level was not associated with antiretroviral therapy and tenofovir disoproxil fumarate. On the other hand, urinary L-FABP level was independently associated with the CKD classification.
Conclusion
Urinary L-FABP may be used as an adjunct to diagnose the CKD stage.
