The effects of THA on scopolamine and nucleus basalis lesion-induced EEG slowing

The effectiveness of THA (an anticholinesterae) on scopolamine (0.4 mg/kg) and nucleus basalis (NB) lesion-induced change in neocortical spectral electroencephalography (EEG) were investigated. Scopolamine increased the amplitudes of all the spectral components in waking-immobility. In the movement-related EEG spectral values, only the alpha power was increased. THA 7.5 mg/kg, but not THA 3 mg/kg, could reverse scopolamine-induced amplitude change. NB lesioning increased delta and theta amplitudes, but decreased beta amplitude. Delta amplitude was increased during movement recordings in NB-lesioned rats. THA 7.5 mg/kg and pilocarpine 10 mg/kg, but not THA 3 mg/kg, could partially reverse the increase of delta and theta amplitudes induced by NB lesions. However, the beta power decrease could not be restored with cholinomimetics. This study demonstrates that quantitative EEG activity analysis may reflect the THA-induced restoration of the function of the cholinergic nucleus basalis.     

Pseudotumors in Small-Head Metal-on-Metal Total Hip Arthroplasties at a Minimum Follow-Up of 20 Years

BackgroundMetal-on-metal (MOM) surfaces in total hip arthroplasty (THA) have been used widely. Serum cobalt and chromium levels have been the standard investigation for follow-up examinations, but magnetic resonance imaging (MRI) with metal artifact reducing sequences has shown good results in detecting pseudotumors. The aim of this study is to survey a significant correlation among MRI findings, serum metal levels, and clinical scores in patients with small-head MOM implants and if serum cobalt and chromium levels are sufficient in detecting patients with pseudotumors in the long-term follow-up.MethodsAt a minimum follow-up of 20 years, 26 patients (29 THAs) of the original 98 patients (105 THAs) included in this study between November 1992 and May 1994 were available for follow-up examination. Clinical scores, serum metal ion levels, and MRIs were obtained.ResultsWe found mean serum cobalt levels of 1.87 μg/L (±3.44) and chromium levels of 2.23 μg/L (±2.96) and very good clinical and functional results (mean Harris Hip Score 88.6) in the long-term follow-up. Pseudotumors were detected in MRIs of 21 hips. There were no significant differences between patients with or without pseudotumors regarding serum metal levels and the correlation for clinical outcome scores, demographic data, and cup inclination. The cumulative rate of survival was still at 91.4% at 22.8 years.ConclusionThis study presents the first published data on small-head MOM hips, comparing metal ion levels, pseudotumors, clinical, and radiological results in a follow-up period of more than 20 years and reveals that serum metal levels are not significantly higher in patients with pseudotumors.Level of EvidenceTherapeutic Level III     

Total Hip Arthroplasty in Patients With Osteoarthritis Associated With Legg-Calve-Perthes Disease: Perioperative Complications and Patient-Reported Outcomes

BackgroundComplications and patient-reported outcomes (PROs) of total hip arthroplasty (THA) in patients with Legg-Calve-Perthes disease (LCPD) have demonstrated variable results. The purpose of this study was to use a validated grading scheme to analyze complications associated with THA in patients with residual LCPD deformities. Second, we report PROs and intermediate-term survivorship in this patient population.MethodsA retrospective, single-center review was performed on 61 hips in 61 patients who underwent THA for residual Perthes disease. Average patient age was 42 years and 26% of hips had previous surgery. Complications were determined and categorized using a validated grading scheme that included five grades based on the treatment required to manage the complication and on persistent disability. PROs were compared from preoperative to most recent follow-up time points.ResultsMajor complications (grade III) occurred in three patients (5%) which each required a second surgical intervention. The most common minor grade I or II complications (11.5%) were asymptomatic heterotopic ossification (3.3%). Patients were lengthened on the surgical side an average of 1.4 cm with no nerve palsies. All patient PROs improved from preoperative to postoperative time points with the modified Harris Hip Score improving from 46.9 preoperatively to 85.4 postoperatively (P < .01). Patients free from revision for any reason at final follow-up (5.6 years; range 2-13 years) was 98.4% with one patient needing a revision of their femoral component.ConclusionsTHA for the sequelae of the LCPD has an acceptable complication rate and provides excellent patient reported outcomes at mid-term follow-up.     

Survivorship of Ceramic-on-Ceramic Total Hip Arthroplasty With Metal-Backed Acetabular Liners at 10 Years

BackgroundCeramic-on-ceramic bearings are becoming increasingly popular in primary total hip arthroplasty (THA). To enhance ceramic-on-ceramic liner exchange in case of revision surgery, metal-backed liner systems have been proposed. Little is known about the clinical performance of these implants. The purpose of this study is to evaluate a metal-backed liner implant system for primary THA.MethodsA total of 422 patients (with 468 consecutive THAs) were followed over a mean period of 10 years. All arthroplasties were performed with a cementless stem, a press-fit cup, and a metal-backed liner system. Surgical and clinical data, complications, and revisions were analyzed. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) before surgery and at 1 and 10 years after surgery were compared.ResultsThe overall 10-year implant survival rate was 93.8%. The survival rate was 97.0% for heads and liners, 97.5% for stem, and 99.3% for acetabular cup. The most common reason for revision was ceramic breakage (2.4%) of the third-generation (BIOLOX forte) acetabular liner. Mean WOMAC score improved significantly from 50.1 before surgery to 13.2 at 1 year after surgery. There was no difference in WOMAC scores between surgical approach and type of bearing at 1 and 10 years after surgery.ConclusionTHA using cementless stem, press-fit cup, and metal-backed liner system provides satisfactory long-term outcomes, with revision rate comparable to that with other systems available in the market. The metal-backed liner system has low risk of mal-seating. Third-generation ceramic liners should be avoided as they seem to be more prone to breakage.     

Some Actions of 9-Amino-1,2,3,4-Tetrahydroacridine (THA) on Cholinergic Transmission and Membrane Currents in Rat Sympathetic Ganglia

THA (Tacrine) is an anticholinesterase drug reported to alleviate cognitive deficit in Alzheimer's disease. We have used rat isolated superior cervical sympathetic ganglia as a model mammalian cholinergic neural system to study effects of THA on cholinergic synaptic transmission and postsynaptic membrane currents. At 0.1 - 3 microM, THA augmented the postsynaptic depolarizations and inward clamp currents produced by acetylcholine but not by the cholinesterase-resistant analogue, DMPP. Higher concentrations depressed these responses to both acetylcholine and DMPP, and reduced the acetylcholine-induced increase in membrane current noise. At 1 microM, THA did not affect the amplitude or time-course of fast (nicotinic) excitatory postsynaptic currents (epscs) evoked by single orthodromic volleys, but higher concentrations induced a biphasic epsc decay. In contrast, low concentrations of THA (1 - 3 microM) greatly augmented and prolonged the muscarinic slow epsc evoked by repetitive orthodromic volleys: this effect was blocked by 1 microM atropine. Concentrations above 0.1 mM produced a membrane depolarization and inhibited a variety of membrane ionic currents, including voltage-gated Ca current and subsequent Ca-activated K currents, and voltage-gated M- and A-type K currents. It is concluded that the principal effect of THA is to inhibit cholinesterase, and that the main consequence of this is to augment and prolong the muscarinic slow epsc. In contrast, the nicotinic fast epsc is not increased but instead may be reduced through a nicotinic channel-blocking action. Although THA could also block several other ion channels the concentrations required were too high to contribute significantly to its principal pharmacological actions on ganglionic transmission.     

Dual mobility: A choice for primary total hip arthroplasty?

Dual-mobility sockets were introduced in the United States in 2010. The smaller inside diameter head offered the potential advantage of lower wear and the larger outside diameter head offered the potential advantage of improved stability. Initially, indications were advocated for patients with increased instability risk. However, with larger diameter metal-on-metal articulations falling out of favor, the indications for dual-mobility components are expanding. The author has used this design in over 400 primary THAs with only one dislocation. One loose cup was revised. Dislocation of the smaller femoral head from the larger polyethylene head remains a theoretical risk with DM designs.     

Femoral Stem Cementation in Hip Arthroplasty: The Know-How of a “Lost” Art

Purpose of ReviewTo describe the (1) indications, (2) preoperative precautions, and (3) stepwise technical details of modern femoral stem cemented fixation.Recent FindingsFemoral stem cementation provides excellent implant longevity with a low periprosthetic fracture rate among patients with compromised bone quality or aberrant anatomy. Unfamiliarity with the details of modern cementation techniques among trainees who may lack frequent exposure to cementing femoral stems may preclude them from offering this viable option to suitable patients in later stages of their careers. As such, maximizing benefit from cemented femoral stem fixation among suitable candidates is contingent upon the meticulous use of modern cementation techniques.SummaryIn addition to proper patient selection, modern cementation techniques emphasize the use of (1) pulsatile lavage of the femoral canal, (2) utilization of epinephrine-soaked swabs, (3) vacuum cement mixing, (4) retrograde cement introduction, (5) cement pressurization, and (6) the use of stem centralizers. Furthermore, identifying and optimizing the preoperative status of at-risk patients with pre-existing cardiopulmonary compromise, in addition to intraoperative vigilance, are essential for mitigating the risk of developing bone cement implantation syndrome. Further research is required to assess the utility of cemented femoral stem fixation among younger patients.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12178-020-09681-5.     

Effects of Ethyl Alcohol Administration to THA Rat Dams During Their Gestation Period on Learning Behavior and on Levels of Monoamines and Metabolites in the Brain of Pups after Birth

Children born from chronic alcoholic mothers have shown behavioral teratogenic effects more frequently than morphological malformations. To investigate the possible mechanisms and evaluate maternal alcohol dosage levels to induce behavioral dysfunctions, we gave pregnant Tokai High Avoider (THA) rats 0, 5,10, and 20% ethanol (EtOH) as drinking water during the gestation period. We evaluated the brain function of pups born of alcohol-administered dams. Sidman avoidance behavior test and the levels of monoamines (nor-adrenalin, dopamine, and serotonin) and metabolites (3,4-dihydroxy-phenyl acetic acid, homovanillic acid, and 5-hydroxyindole acetic acid) in whole brain were examined for neurobehavioral and neurochemical effects. EtOH-exposed THA offsprings showed high pre-and postnatal mortality, growth deficits, and brain weight reductions. Compared with the results of the same conditioning experiment using Wistar rats, the THA rat may have higher susceptibility to the effects of in utero EtOH exposure than Wistar rats. EtOH-exposed THA pups exhibited deficits in avoidance operant learning that were not shown in Wistar rats. We also observed the increased levels of all monoamines that were assumed to be related with the deficit of learning, the decreased levels of 3,4-dihydroxyphenyl acetic acid and homovanillic acid, and the unchanged levels of 5-hydroxyindole acetic acid in pups from dams administered 10 and 20% EtOH. However, contrary alteration of monoamines and their metabolites were shown in pups from 5% EtOH-administered dams.     

Influence of Renal Function on the Pharmacokinetics,Pharmacodynamics, Efficacy,and Safety of Non–Vitamin K Antagonist Oral Anticoagulants

With the growing integration of non–vitamin K antagonist oral anticoagulants (NOACs) into clinical practice, questions have arisen regarding their use in special populations, including groups that may have been underrepresented in clinical trials. Patients with renal impairment, particularly in the lower echelons of renal function, are one such group. In an effort to elucidate the current evidence regarding the use of NOACs in patients with renal impairment, a systematic assessment of the literature was performed. The MEDLINE database was interrogated for studies and analyses evaluating the influence of renal function on the pharmacokinetics, pharmacodynamics, efficacy, and safety of NOACs published from January 1, 2000, through August 2, 2017. The 82 relevant publications retrieved highlight the diversity in the NOAC class regarding the impact of renal function on drug clearance, drug exposures, and clinical trial outcomes. In several large clinical trials, subgroup analyses revealed no significant differences when patients were stratified by creatinine clearance as a measure of renal function. Efficacy findings, in particular, were largely aligned with the overall population in the included studies. However, relative risks of bleeding were shown to vary, sometimes driven by changes in bleeding event rates in the comparator arm (eg, warfarin, enoxaparin). With few exceptions, minimal influence of mild renal impairment was observed on the relative efficacy and safety of NOACs. Taken together, the evidence suggests that the presence of renal impairment merits careful consideration of anticoagulant choice but should not deter physicians from appropriate use of NOACs.     

The Cementless Anatomic Benoist Girard (ABG) II Total Hip Arthroplasty : A Minimum 8-Year Follow-Up Study

We have evaluated 90 consecutive primary cementless ABG II total hip replacements. The bearings combined metal-on-polyethylene in 64 hips, and alumina-on-alumina in 26 hips. At the minimum 8-year follow-up, ten patients had died, seven had been lost to follow-up, two had undergone revision of either or both components, and 68 were still alive and had not been revised. With revision for any reason as the endpoint, the cumulative survival rate at 10 years was 97.5% ± 1.7%, and 98.7% ± 1.3% for the metal-back cup and the femoral component, respectively. No hip showed peri-acetabular osteolysis. The ABG II total hip arthroplasty has demonstrated favourable clinical and radiological outcomes as well as survival in the current series. Further follow-up is needed to confirm these mid-term results.