Stress induces behavioral abnormalities by increasing expression of phagocytic receptor MERTK in astrocytes to promote synapse phagocytosis.

Childhood neglect and/or abuse can induce mental health conditions with unknown mechanisms. Here, we identified stress hormones as strong inducers of astrocyte-mediated synapse phagocytosis. Using in vitro, in vivo, and human brain organoid experiments, we showed that stress hormones increased the expression of the Mertk phagocytic receptor in astrocytes through glucocorticoid receptor (GR). In post-natal mice, exposure to early social deprivation (ESD) specifically activated the GR-MERTK pathway in astrocytes, but not in microglia. The excitatory post-synaptic density in cortical regions was reduced in ESD mice, and there was an increase in the astrocytic engulfment of these synapses. The loss of excitatory synapses, abnormal neuronal network activities, and behavioral abnormalities in ESD mice were largely prevented by ablating GR or MERTK in astrocytes. Our work reveals the critical roles of astrocytic GR-MERTK activation in evoking stress-induced abnormal behaviors in mice, suggesting GR-MERTK signaling as a therapeutic target for stress-induced mental health conditions.

Mean 23-Year Outcomes of Total Hip Arthroplasty Using a Modular Femoral Stem With Metaphyseal Fixation Sleeve.

BACKGROUND: Although the modular sleeve concept for femoral implants has several advantages, studies reporting on greater than 20-year outcomes are limited. This study aimed to report the mean 23-year results of total hip arthroplasty (THA) using a modular stem with metaphyseal fixation sleeve. METHODS: This study reviewed primary THAs performed using a modular stem between October 1994 and April 1998. Of the 272 hips (221 patients) identified, 220 hips (177 patients) satisfying the minimum 20-year follow-up were included. The Harris Hip Score was used for clinical evaluation. Final hip radiographs were analyzed to evaluate the implant stability and the extent of femoral osteolysis. The mean follow-up duration was 23 years (range, 20 to 28). RESULTS: The mean Harris Hip Score improved from 38 points (range, 26 to 67) preoperatively to 90 points (range, 71 to 100) at the final follow-up (P < .001). Femoral osteolysis was observed in 146 hips (67.1%), but 145 were located proximal to the osseo-integrated sleeve. Overall, 4 femoral revisions were performed; 2 for chronic infection, one for aseptic loosening, and one for periprosthetic femoral fracture. Of the 19 (8.6%) periprosthetic femoral fractures, the most common type was Vancouver AG (13 hips). One (0.5%) asymptomatic distal stem fracture occurred, while no complications were identified at the stem-sleeve junction. Implant survivorship free of any femoral revision was 98.3% at 23 years. CONCLUSIONS: A THA using a modular stem with metaphyseal fixation sleeve demonstrated 98.3% stem survivorship with excellent clinical outcomes at a mean follow-up of 23 years in non-obese patients.

Bearing-Related Complications of Total Hip Arthroplasty Using Fourth-Generation Ceramic-On-Ceramic Articulations: Does Articular Noise Increase Over Time?

BACKGROUND: We previously reported the mean 6-year outcomes of total hip arthroplasty (THA) using fourth-generation ceramic-on-ceramic (CoC) articulations. With extended observations, this study aimed to report the mean 12-year outcomes focusing on bearing-related complications of CoC THA. METHODS: We reviewed primary CoC THAs performed between May 2009 and April 2012 at a single institution. Of the 831 hips (739 patients), 716 hips (635 patients) that satisfied a minimum 10-year follow-up were included. The mean age at operation was 54 years (range, 16 to 83). The occurrence of bearing-specific complications, including ceramic fractures and noise generation, was evaluated. The mean follow-up duration was 12 years (range, 10 to 14). RESULTS: A total of 2 (0.3%) ceramic liner fractures occurred, as previously reported. No additional ceramic fractures were observed during the extended follow-up period. However, the cumulative incidence of audible noise increased from 6.4 (48 of 749) to 8.2% (59 of 716). Of the 59 hips with noise, 26 (44.1%) developed noise within 1 year, whereas 13 (22.0%) presented with noise more than 5 years after THA. The noise was described as clicking in 35 hips (4.9%) and as squeaking in 24 hips (3.4%). No revision surgeries were performed for noise, except in 2 cases of concomitant liner fractures. The implant survivorship free of any revision was 98.1% at 12 years. CONCLUSIONS: No additional ceramic fractures were identified in this extension study at a minimum follow-up of 10 years. However, the prevalence of articular noise has increased from 6.4 to 8.2% since the previous report. Possible late-onset noise should be considered when performing CoC THA in younger patients.

OsLRR-RLP2 Gene Regulates Immunity to Magnaporthe oryzae in Japonica Rice.

Rice is an important cereal crop worldwide, the growth of which is affected by rice blast disease, caused by the fungal pathogen Magnaporthe oryzae. As climate change increases the diversity of pathogens, the disease resistance genes (R genes) in plants must be identified. The major blast-resistance genes have been identified in indica rice varieties; therefore, japonica rice varieties with R genes now need to be identified. Because leucine-rich repeat (LRR) domain proteins possess R-gene properties, we used bioinformatics analysis to identify the rice candidate LRR domain receptor-like proteins (OsLRR-RLPs). OsLRR-RLP2, which contains six LRR domains, showed differences in the DNA sequence, containing 43 single-nucleotide polymorphisms (SNPs) in indica and japonica subpopulations. The results of the M. oryzae inoculation analysis indicated that indica varieties with partial deletion of OsLRR-RLP2 showed susceptibility, whereas japonica varieties with intact OsLRR-RLP2 showed resistance. The oslrr-rlp2 mutant, generated using clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9), showed increased pathogen susceptibility, whereas plants overexpressing this gene showed pathogen resistance. These results indicate that OsLRR-RLP2 confers resistance to rice, and OsLRR-RLP2 may be useful for breeding resistant cultivars.

Long-Term Outcomes of Cementing Highly Cross-Linked Polyethylene Liners Into Well-Fixed Acetabular Shells in Revision Total Hip Arthroplasty.

BACKGROUND: Cementing a new liner into a secure, well-positioned metallic shell can be a less-invasive strategy in revision total hip arthroplasty (THA). This study aimed to report the mean 14-year outcomes of cementing highly cross-linked polyethylene (XLPE) liners into well-fixed acetabular shells in revision THAs. METHODS: This study reviewed a single-surgeon series of cementing XLPE liners into well-fixed acetabular components. Of the 52 hips (51 patients) evaluated, 48 hips (47 patients) that satisfied a minimum follow-up of 10 years were included. The Harris Hip score was used for clinical evaluation. Final hip radiographs were used to determine the extent of acetabular osteolysis and stability of the components. The mean age at index operation was 53 years (range, 32 to 72). The mean follow-up duration was 14 years (range, 10 to 18). RESULTS: The mean Harris Hip score improved from 58 points (range, 23-81) preoperatively to 91 points (range, 45-100) at the final evaluation (P < .001). A total of 3 acetabular rerevisions were performed, all for aseptic loosening of the outer shell. One postoperative dislocation occurred, but it was successfully treated with a closed reduction. Final radiographs showed a significant reduction in acetabular osteolysis (P < .001). Implant survivorship free from any rerevision was 93.3% (95% confidence interval, 85.9-100%) at 14 years. CONCLUSION: Cementing an XLPE liner into a well-fixed acetabular shell in revision THA demonstrated excellent clinical and radiographic outcomes at a mean of 14 years postoperatively. This technique could be a safe and durable option in the absence of XLPE liners compatible with preimplanted shells.

Incidence and Risk Factors of Iliopsoas Tendinopathy After Total Hip Arthroplasty: A Radiographic Analysis of 1,602 Hips.

BACKGROUND: Iliopsoas tendinopathy (IPT) can cause persistent groin pain and lead to dissatisfaction after total hip arthroplasty (THA). This study aimed to report the characteristics, incidences, risk factors, and treatment outcomes of IPT after THA. METHODS: We reviewed primary THAs performed at a single institution between January 2012 and May 2018. Clinical and radiographic analyses were performed on 1,602 THAs (1,370 patients). Patient characteristics, component sizes, inclination and anteversion angles, and antero-inferior cup prominence (≥8 millimeters (mm)), were compared between the groups with and without IPT. Changes in teardrop to lesser trochanter distance were measured to estimate changes in leg length and horizontal offset caused by THA. Logistic regression models were used to identify the risk factors for IPT. IPT was identified in 53 hips (3.3%). RESULTS: Patients with IPT had greater leg lengthening (12.3 versus 9.3 mm; P = .001) and higher prevalence of antero-inferior cup prominence (5.7 versus 0.4%; P = .002). There was no significant difference in inclination, anteversion, and horizontal offset change between the two groups. In multivariate analyses, greater leg lengthening, prominent acetabular cup, women, and higher body mass index were associated with IPT. All patients reported improvement in groin pain after arthroscopic tenotomy, while 35.7% with nonoperative management reported improvement (P < .001). CONCLUSIONS: Symptomatic IPT occurred in 53 (3.3%) of the 1,602 primary THAs. Our findings suggest that leg lengthening as well as prominent acetabular cup in THAs can be associated with the development of IPT. Arthroscopic tenotomy was effective in relieving groin pain caused by IPT.

Rectangular Taper Stem Designs Are Associated With a Higher Risk for Periprosthstic Femoral Fractures After Cementless Total Hip Arthroplasty.

BACKGROUND: Periprosthetic femoral fractures (PFFs) remain a major concern following cementless total hip arthroplasty (THA). This study aimed to evaluate the association between different types of cementless tapered stems and the risk of postoperative PFF. METHODS: A retrospective review of primary THAs performed at a single center from January 2011 to December 2018 included 3,315 hips (2,326 patients). Cementless stems were classified according to their design. The incidence of PFF was compared between flat taper porous-coated stems (type A), rectangular taper grit-blasted stems (type B1), and quadrangular taper hydroxyapatite-coated stems (type B2). Multivariate regression analyses were performed to identify independent factors related to PFF. The mean follow-up duration was 61 months (range, 12 to 139). Overall, 45 (1.4%) postoperative PFFs occurred. RESULTS: The incidence of PFF was significantly higher in type B1 stems than in type A and type B2 stems (1.8 versus 0.7 versus 0.7%; P = .022). Additionally, more surgical treatments (1.7 versus 0.5 versus 0.7%; P = .013) and femoral revisions (1.2 versus 0.2 versus 0%; P = .004) were required for PFF in type B1 stems. After controlling for confounding variables, older age, diagnosis of hip fracture, and use of type B1 stems were significant factors associated with PFF. CONCLUSION: Type B1 rectangular taper stems were found to have higher risks for postoperative PFF and PFF requiring surgical management than type A and type B2 stems in THA. Femoral stem geometry should be considered when planning for cementless THA in elderly patients who have compromised bone quality.

Long-Term Outcomes of Revision Total Hip Arthroplasty Using a Tapered and Fluted Modular Stem: A Mean Follow-Up of 16 Years.

BACKGROUND: Tapered modular stems are increasingly used in revision total hip arthroplasty (THA) with deficient femoral bone stock. This study aimed to report the long-term outcomes of revision THA using a tapered and fluted modular stem. METHODS: Between December 1998 and February 2006, 113 revision THAs (110 patients) were performed with a tapered and fluted modular stem at a single institution. Hip radiographs were used to identify stem subsidence, stability, and femoral radiolucency. Final outcomes were assessed in 72 hips (70 patients), with a minimum follow-up of 10 years. RESULTS: The mean follow-up duration was 16 years (range, 10-23). At the final evaluation, the Harris Hip Score improved from a mean of 41 points (range, 10-72) preoperatively to 83 points (range, 56-100) (P < .001). Six femoral re-revisions were performed for the following reasons: 1 aseptic loosening, 2 stem fractures, and 3 infections. One stem fracture occurred at the modular junction after 14 years, and the other at a more distal location after 15 years. Stem subsidence was >5 mm in 6 hips (9.1%), but secondary stability was achieved in all stems. Osseointegration was observed in 63 (95.5%) hips. Stem survivorship was 91.1% with an end point of any re-revision and 94.6% for aseptic re-revision. CONCLUSION: A tapered and fluted modular stem demonstrated excellent implant survivorship with reliable bony fixation at a mean follow-up of 16 years. This type of stem can be a durable option for revision THA in patients who have femoral defects.

Outcomes of revision total hip arthroplasty using the modular dual mobility acetabular system to treat recurrent dislocation.

BACKGROUND: Recurrent dislocation is a difficult complication after total hip arthroplasty (THA). This study aimed to report the clinical and radiographic outcomes of revision THA using the modular dual mobility (MDM) acetabular system to treat recurrent dislocation. METHODS: Between March 2015 and February 2019, 34 revision THAs were performed using the MDM system for treating recurrent dislocation in a single institution. Of these, 32 revision THAs (32 patients) that satisfied a minimum follow-up of one year (mean, 4 years) were included in this study. Patient-reported outcomes, complication rates, and radiographic results were evaluated. RESULTS: Seventeen patients (53.1%) had lumbar degenerative kyphosis, and six (18.8%) had surgically fused lumbar spines during the index operation. All acetabular components were revised, whereas femoral stems were retained in 29 patients (90.6%). No redislocation or intraprosthetic dislocation was noted after revision. One additional revision was required for acetabular loosening with periprosthetic joint infection. No additional revision was performed for aseptic loosening. A partial radiolucent line was found in two hips (6.3%) confined to one acetabular zone. CONCLUSIONS: Revision THA using the MDM system was effective in treating recurrent dislocation in a group of patients with a high prevalence of lumbar spinal pathology. During a mean follow-up of 4 years, one additional revision THA was performed for septic loosening and none for aseptic loosening.

Therapeutic effects of stiripentol against ischemia-reperfusion injury in gerbils focusing on cognitive deficit, neuronal death, astrocyte damage and blood brain barrier leakage in the hippocampus.

Stiripentol is an anti-epileptic drug for the treating of refractory status epilepticus. It has been reported that stiripentol can attenuate seizure severity and reduce seizure-induced neuronal damage in animal models of epilepsy. The objective of the present study was to investigate effects of post-treatment with stiripentol on cognitive deficit and neuronal damage in the cornu ammonis 1 (CA1) region of the hippocampus proper following transient ischemia in the forebrain of gerbils. To evaluate ischemia-induced cognitive impairments, passive avoidance test and 8-arm radial maze test were performed. It was found that post-treatment with stiripentol at 20 mg/kg, but not 10 or 15 mg/kg, reduced ischemia-induced memory impairment. Transient ischemia-induced neuronal death in the CA1 region was also significantly attenuated only by 20 mg/kg stiripentol treatment after transient ischemia. In addition, 20 mg/kg stiripentol treatment significantly decreased ischemia-induced astrocyte damage and immunoglobulin G leakage. In brief, stiripentol treatment after transient ischemia ameliorated transient ischemia-induced cognitive impairment in gerbils, showing that pyramidal neurons were protected and astrocyte damage and blood brain barrier leakage were significantly attenuated in the hippocampus. Results of this study suggest stiripentol can be developed as a candidate of therapeutic drug for ischemic stroke.

Long-Term Alternating Fasting Increases Interleukin-13 in the Gerbil Hippocampus, But Does Not Protect BBB and Pyramidal Neurons From Ischemia-Reperfusion Injury.

It is questionable whether intermittent fasting (IF) protects against brain ischemic injury. This study examined whether IF increased anti-inflammatory cytokines and protected neurons from ischemia-reperfusion injury in the gerbil hippocampus. Gerbils were subjected to 1-day alternating fasting as IF for 1, 2, or 3 months and assigned to sham or 5 min of transient ischemia. We examined the changes in anti-inflammatory cytokines (IL-4 and IL-13), neurons and IgG by immunohistochemistry or immunofluorescence staining in the cornu ammonis 1 (CA1) region of the hippocampus before and after ischemia. IF increased IL-13 immunoreactivity in the CA1 region before ischemia, but did not affect IL-4 immunoreactivity. After ischemia, IL-13 and 4 immunoreactivities in the CA1 region were significantly lower in IF gerbils than in non-IF gerbils. In the IF gerbils, the CA1 pyramidal neurons were not protected from ischemic injury; in these gerbils, strong IgG immunoreactivity was seen in the CA1 parenchyma, indicating leakage of the BBB. In brief, IF increased IL-13 in the CA1 region, but these neurons were not protected from transient ischemic injury evidenced by IgG immunoreactivity in the CA1 parenchyma. This study indicates that IF increased some anti-inflammatory cytokines but did not afford neuroprotection against ischemic insults via BBB disruption.

Out-of-Hospital Cohort Treatment of Coronavirus Disease 2019 Patients with Mild Symptoms in Korea: an Experience from a Single Community Treatment Center.

The outbreak of Coronavirus Disease 2019 (COVID-19) caused a worldwide pandemic. Less than 6 weeks after the first confirmed cases in Korea, the patient number exceeded 5,000, which overcrowded limited hospital resources and forced confirmed patients to stay at home. To allocate medical resources efficiently, Korea implemented a novel institution for the purpose of treating patients with cohort isolation out of hospital, namely the Community Treatment Center (CTC). Herein, we report results of the initial management of patients at one of the largest CTC in Korea. A total of 309 patients were admitted to our CTC. During the first two weeks, 7 patients were transferred to the hospital because of symptom aggravation and 107 patients were discharged without any complication. Although it is a novel concept and may have some limitations, CTC may be a very cost-effective and resource-saving strategy in managing massive cases of COVID-19 or other emerging infectious diseases.

Artificial Intelligence in Health Care: Current Applications and Issues.

In recent years, artificial intelligence (AI) technologies have greatly advanced and become a reality in many areas of our daily lives. In the health care field, numerous efforts are being made to implement the AI technology for practical medical treatments. With the rapid developments in machine learning algorithms and improvements in hardware performances, the AI technology is expected to play an important role in effectively analyzing and utilizing extensive amounts of health and medical data. However, the AI technology has various unique characteristics that are different from the existing health care technologies. Subsequently, there are a number of areas that need to be supplemented within the current health care system for the AI to be utilized more effectively and frequently in health care. In addition, the number of medical practitioners and public that accept AI in the health care is still low; moreover, there are various concerns regarding the safety and reliability of AI technology implementations. Therefore, this paper aims to introduce the current research and application status of AI technology in health care and discuss the issues that need to be resolved.

Outcomes of Cerclage Cabling for Intraoperative Calcar Cracks in Cementless Total Hip Arthroplasty Using Broach-Only, Tapered Wedge Stems.

BACKGROUND: Intraoperative femoral fractures are well-known but often overlooked complications in total hip arthroplasty (THA). We examined outcomes of cerclage cabling for intraoperative calcar cracks in THA with cementless tapered wedge stems. METHODS: In total, 4928 primary THAs were performed using broach-only, tapered wedge stems between January 2007 and November 2017 in a single institution. Of these, we identified 71 intraoperative calcar cracks (69 patients) managed by 2-mm cerclage cables. Clinical outcomes, amount of stem subsidence, and implant survivorship of the calcar crack group (68 THAs) were compared with those of the matched control group (68 THAs) without intraoperative fractures. Multivariate analysis was performed to identify potential risk factors for stem subsidence >3 mm. RESULTS: The mean stem subsidence was greater in the calcar crack group (2.0 vs 1.2 mm, P = .021), whereas revision-free survivorships of THA were similar between groups at 6 years (98.5% vs 98.4%; log-rank, P = .987). In the calcar crack group, a Dorr type C femur and the absence of cabling proximal to the lesser trochanter (LT) were identified as independent risk factors for stem subsidence >3 mm. For the subgroup with 42 calcar cracks managed by a single cable applied proximal to the LT, revision-free survivorship of THA was 100% at 6 years. There was no complete radiolucency to indicate aseptic stem loosening in either group. CONCLUSION: The application of a single cable proximal to the LT of the femur for intraoperative calcar cracks demonstrated 100% revision-free survivorship with lower stem subsidence in THA with tapered wedge stems.

Total Hip Arthroplasty With Subtrochanteric Shortening Osteotomy in Patients With High Hip Dislocation Secondary to Childhood Septic Arthritis: A Matched Comparative Study With Crowe IV Developmental Dysplasia.

BACKGROUND: Total hip arthroplasty (THA) with subtrochanteric shortening osteotomy (SSO) is performed to manage hips with high dislocations. We compared outcomes of THA with SSO in patients with high hip dislocation resulting from childhood septic arthritis and Crowe IV developmental dysplasia of the hip (DDH). METHODS: We reviewed 60 THAs with SSO performed between May 1996 and December 2013. Thirty-one cases were classified as sequelae of childhood infection and 29 as DDH. Twenty-five hips were selected for each group after the propensity score was matched with preoperative demographics and leg length discrepancy (LLD). Clinical scores, complication and reoperation rates, radiographic results, and survivorships were compared. The mean duration of follow-up was 12.3 (range 5-22) years. RESULTS: The average correction in LLD was 2.5 cm for childhood infection and 3.6 cm for DDH (P = .002). The infection group received more transfusions (mean 3.3 vs 2.0 units, P = .002), required more time for union of osteotomy site (mean 6.8 vs 5.2 months, P = .042), and reported lower Harris Hip Score (mean 85.1 vs 91.3, P = .017). Reoperations were performed in 11 (44%) previously infected hips and 3 (12%) DDHs (P = .012). Kaplan-Meier survivorship with an endpoint of revision for any reason was lower in the infection group (83.6%) than in the DDH group (100%) at 10 years (log rank, P = .040). CONCLUSION: THA with SSO in high hip dislocation secondary to childhood septic arthritis demonstrated less favorable clinical outcomes with increased risks of complication, compared with those performed in Crowe IV DDH with similar degree of chronic dislocation.

Effects of regional body temperature variation during asphyxial cardiac arrest on mortality and brain damage in a rat model.

To date, hypothermia has focused on improving rates of resuscitation to increase survival in patients sustaining cardiac arrest (CA). Towards this end, the role of body temperature in neuronal damage or death during CA needs to be determined. However, few studies have investigated the effect of regional temperature variation on survival rate and neurological outcomes. In this study, adult male rats (12 week-old) were used under the following four conditions: (i) whole-body normothermia (37 ± 0.5 °C) plus (+) no asphyxial CA, (ii) whole-body normothermia + CA, (iii) whole-body hypothermia (33 ± 0.5 °C)+CA, (iv) body hypothermia/brain normothermia + CA, and (v) brain hypothermia/body normothermia + CA. The survival rate after resuscitation was significantly elevated in groups exposed to whole-body hypothermia plus CA and body hypothermia/brain normothermia plus CA, but not in groups exposed to whole-body normothermia combined with CA and brain hypothermia/body normothermia plus CA. However, the group exposed to hypothermia/brain normothermia combined with CA exhibited higher neuroprotective effects against asphyxial CA injury, i.e. improved neurological deficit and neuronal death in the hippocampus compared with those involving whole-body normothermia combined with CA. In addition, neurological deficit and neuronal death in the group of rat exposed to brain hypothermia/body normothermia and CA were similar to those in the rats subjected to whole-body normothermia and CA. In brief, only brain hypothermia during CA was not associated with effective survival rate, neurological function or neuronal protection compared with those under body (but not brain) hypothermia during CA. Our present study suggests that regional temperature in patients during CA significantly affects the outcomes associated with survival rate and neurological recovery.

A Minimum of 15-Year Results of Cementless Total Hip Arthroplasty Using a 28-mm Metal-On-Metal Articulation.

BACKGROUND: We previously reported unexpected early failures of total hip arthroplasty (THA) utilizing a 28-mm Ultima metal-on-metal (MoM) articulation. However, long-term results of small-diameter MoM THAs still remain unclear. The purpose of this study was to evaluate the clinical and radiographic outcomes of the previously reported cohort at a minimum follow-up of 15 years. METHODS: The original cohort consisted of 171 primary THAs (167 patients) using a 28-mm MoM articulation performed between April 2000 and March 2002. Of these, 130 hips (126 patients) were reviewed at an average follow-up of 17.1 (range, 15-18) years. Clinical score, complications, presence of osteolytic lesion, serum metal ion concentrations, and implant survivorships were evaluated. RESULTS: The mean Harris Hip Score improved from 44.9 points preoperatively to 90.5 points at the latest follow-up. During the entire period since the original surgery, a total of 5 revisions (3.8%) were associated with adverse reaction to metal debris (ARMD). The last revision surgery for symptomatic ARMD was performed at 6 years postoperatively. The implant survivorships with an end point of revision for aseptic failure and for any reason were 95.4% and 93.8%, respectively. Radiographic osteolytic lesions were detected in 27 hips (20.8%). The average serum metal concentration was 2.50 (range, 0.12-9.86) µg/L for cobalt and 2.81 (range, 0.82-12.3) µg/L for chromium. CONCLUSIONS: THA using a 28-mm MoM articulation showed favorable long-term outcomes with a relatively high revision-free survival rate. There was no significant symptomatic ARMD after the last acetabular revision performed at 6 years postoperatively.

Femoral Stem Survivorship in Dorr Type A Femurs After Total Hip Arthroplasty Using a Cementless Tapered Wedge Stem: A Matched Comparative Study With Type B Femurs.

BACKGROUND: There is a lack of understanding on relationship between the femoral geometry and outcomes of total hip arthroplasty (THA). We investigated clinical and radiographic outcomes of THA using a cementless tapered wedge stem in patients with Dorr type A proximal femoral morphology and compared with those of type B femurs at a minimum follow-up of 5 years. METHODS: We analyzed 1089 hips (876 patients) that underwent THA using an identical cementless tapered wedge stem. We divided all femurs into 3 types (Dorr type A, B, and C). Type A and B femurs were statistically matched with age, gender, body mass index, and diagnosis by using propensity score matching. Clinical, radiographic results, and stem survivorship were compared between the matched 2 groups. RESULTS: A total of 611 femurs (56%) were classified as type A, 427 (39%) as type B, and 51 (5%) as type C. More radiolucent lines around femoral stems were found in type A femurs (7.8%) than in type B femurs (2.5%) (P < .001). Patients with radiolucency showed worse Harris Hip Score (86.2 points) compared with those without radiolucency (93.0 points) (P < .001). The stem survivorship of type A femur (97.8%) was lower than that of type B femur (99.5%) (P = .041). The reasons for femoral revision in type A femurs were periprosthetic fracture (67%), aseptic loosening (22%), and deep infection (11%). CONCLUSIONS: This study showed a higher rate of complications after THAs using a cementless tapered wedge stem in Dorr type A femurs than those performed in type B femurs.

Accelerated Thermal Depolymerization of Cyclic Polyphthalaldehyde with a Polymeric Thermoacid Generator.

Thermally triggerable polymer films that degrade at modest temperatures (≈85 °C) are created from a blend of cyclic polyphthalaldehyde (cPPA) and a polymeric thermoacid generator, poly(vinyl tert-butyl carbonate sulfone) (PVtBCS). PVtBCS depolymerizes when heated, generating acid which initiates the depolymerization of cPPA into volatile byproducts. The mass loss onset for 2 wt% PVtBCS/cPPA is 22 °C lower than the onset for neat cPPA alone in dynamic thermogravimetric analysis experiments. Increased concentrations of PVtBCS increase the rate of depolymerization of cPPA. Raman spectroscopy reveals that the monomer, o-phthalaldehyde, is the main depolymerization product of the acid-catalyzed depolymerization of cPPA. The PVtBCS/cPPA blend is a promising material for the design and manufacture of transient electronic packaging and polymers.

Serial Evaluation of Endometrial Blood Flow for Prediction of Pregnancy Outcomes in Patients Who Underwent Controlled Ovarian Hyperstimulation and In Vitro Fertilization and Embryo Transfer.

OBJECTIVES: To investigate endometrial blood flow during the menstrual cycle in patients undergoing controlled ovarian hyperstimulation (COH), in vitro fertilization (IVF), and embryo transfer (ET) and prediction of pregnancy outcomes based on these characteristics. METHODS: Endometrial blood flow was measured in 35 patients undergoing COH and IVF-ET (nonpregnant [n = 15] and pregnant [n = 20]) by measuring the resistive index (RI) of the uterine radial artery using 2-dimensional Doppler ultrasonography. Measurements were obtained in 4 different phases of the menstrual cycle day: early follicular, midfollicular, preovulatory, and midluteal. RESULTS: The uterine radial artery RI during the early follicular phase was significantly lower in the pregnant group than in the nonpregnant group (mean ± SD, 0.61 ± 0.01 versus 0.66 ± 0.01; P = .029). There was no significant difference between groups during the midfollicular, preovulatory, and midluteal phases (mean ± SD, 0.60 ± 0.02 versus 0.60 ± 0.01; P = .84; 0.61 ± 0.09 versus 0.57 ± 0.01; P = .12; 0.54 ± 0.01 versus 0.57 ± 0.02; P = .32, respectively). There was a significant difference in endometrial blood flow between the pregnant and nonpregnant groups during each phase (P = .016). The difference in the changes of the uterine radial artery RI from the preovulatory to midluteal phase between the pregnant and non pregnant groups was significant (-0.002 ± 0.03 versus 0.07 ± 0.02; P = .038). CONCLUSIONS: Increased endometrial blood flow during the midluteal phase, compared to the preovulatory phase, may correlate with successful COH and IVF-ET. Additionally, sufficient blood flow at initiation of COH may affect COH and IVF-ET results.