Air dispersal of multi-drug-resistant organisms including meticillin-resistant Staphylococcus aureus, carbapenem-resistant Acinetobacter baumannii and carbapenemase-producing Enterobacterales in general wards: surveillance culture of air grilles.

BACKGROUND: The environmental surveillance of air grilles in clinical areas has not been systematically analysed. METHODS: Samples were collected from frequently touched items (N = 529), air supply (N = 295) and exhaust (N = 184) grilles in six medical and 11 surgical wards for the cultures of multi-drug-resistant organisms (MDROs): meticillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenemase-producing Enterobacterales (CPE), and isolates were selected for whole-genome sequencing (WGS). The contamination rates were correlated with the colonization pressures of the respective MDROs. RESULTS: From 3rd October to 21st November 2023, 9.8% (99/1008) of the samples tested positive, with MRSA (24.2%, 24/99), CRAB (59.6%, 59/99) and CPE (2.0%, 2/99), being the only detected MDROs. The contamination rate in air exhaust grilles (26.6%, 49/184) was significantly higher than in air supply grilles (5.8%, 17/295; P<0.001). The contamination rate of air exhaust grilles with any MDRO in acute medical wards (73.7%, 14/19) was significantly higher than in surgical wards (12.5%, 4/32; P<0.001). However, there was no difference in the contamination rate of air exhaust grilles between those located inside and outside the cohort cubicles for MDROs (27.1%, 13/48 vs 28.8%, 30/104; P=0.823). Nevertheless, the weekly CRAB colonization pressure showed a significant correlation with the overall environmental contamination rate (r = 0.878; 95% confidence interval (CI): 0.136-0.986; P=0.004), as well as with the contamination rate in air supply grilles (r = 0.960; 95% CI: 0.375-0.999; P<0.001) and air exhaust grilles (r = 0.850; 95% CI: 0.401-0.980; P=0.008). WGS demonstrated clonal relatedness of isolates collected from patients and air exhaust grilles. CONCLUSIONS: Air grilles may serve as MDRO reservoirs. Cohort nursing in open cubicles may not completely prevent MDRO transmission through air dispersal, prompting the consideration of future hospital design.

NMR-based metabolomics for the environmental assessment of Kaohsiung Harbor sediments exemplified by a marine amphipod (Hyalella azteca).

Inflow of wastewater from upstream causes a large flux of pollutants to enter Kaohsiung Harbor in Taiwan daily. To reveal the ecological risk posed by Kaohsiung Harbor sediments, an ecological metabolomic approach was employed to investigate environmental factors pertinent to the physiological regulation of the marine amphipod Hyalella azteca. The amphipods were exposed to sediments collected from different stream inlets of the Love River (LR), Canon River (CR), Jen-Gen River (JR), and Salt River (SR). Harbor entrance 1 (E1) was selected as a reference site. After 10-day exposure, metabolomic analysis of the Hyalella azteca revealed differences between two groups: {E1, LR, CR} and {JR, SR}. The metabolic pathways identified in the two groups of amphipods were significantly different. The results demonstrated that NMR-based metabolomics can be effectively used to characterize metabolic response related to sediment from polluted areas.

Ultrasound-guided synovial Tru-cut biopsy: indications, technique, and outcome in 111 cases.

OBJECTIVE: To investigate the diagnostic performance of ultrasound-guided synovial biopsy. METHODS: Clinical notes, pathology and microbiology reports, ultrasound and other imaging studies of 100 patients who underwent 111 ultrasound-guided synovial biopsies were reviewed. Biopsies were compared with the final clinical diagnosis established after synovectomy (n = 43) or clinical/imaging follow-up (n = 57) (mean 30 months). RESULTS: Other than a single vasovagal episode, no complication of synovial biopsy was encountered. One hundred and seven (96 %) of the 111 biopsies yielded synovium histologically. Pathology ± microbiology findings for these 107 conclusive biopsies comprised synovial tumour (n = 30, 28 %), synovial infection (n = 18, 17 %), synovial inflammation (n = 45, 42 %), including gouty arthritis (n = 3), and no abnormality (n = 14, 13 %). The accuracy, sensitivity, and specificity of synovial biopsy was 99 %, 97 %, and 100 % for synovial tumour; 100 %, 100 %, and 100 % for native joint infection; and 78 %, 45 %, and 100 % for prosthetic joint infection. False-negative synovial biopsy did not seem to be related to antibiotic therapy. CONCLUSION: Ultrasound-guided Tru-cut synovial biopsy is a safe and reliable technique with a high diagnostic yield for diagnosing synovial tumour and also, most likely, for joint infection. Regarding joint infection, synovial biopsy of native joints seems to have a higher diagnostic yield than that for infected prosthetic joints. KEY POINTS: • Ultrasound-guided Tru-cut synovial biopsy has high accuracy (99 %) for diagnosing synovial tumour. • It has good accuracy, sensitivity, and high specificity for diagnosis of joint infection. • Synovial biopsy of native joints works better than biopsy of prosthetic joints. • A negative synovial biopsy culture from a native joint largely excludes septic arthritis. • Ultrasound-guided Tru-cut synovial biopsy is a safe and well-tolerated procedure.

An Unusual Hydrops Fetalis Associated with Compound Heterozygosity for Krüppel-like Factor 1 mutations.

Hydrops fetalis is commonly due to Hb Bart's (γ4) disease in South East Asia. Here, we report an unusual case of hydrops fetalis due to congenital dyserythropoietic anemia (CDA) associated with compound heterozygosity for Krüppel-like factor 1 (KLF1) gene mutations. Fetal cardiomegaly was first detected on routine mid-trimester scan in a pregnant woman with normal mean corpuscular volume (MCV) and Rhesus positive status. The fetus subsequently developed hydrops fetalis, and cordocentesis showed severe fetal anemia with a hemoglobin (Hb) level of 3.4 g/dL. Common causes of fetal anemia including Hb Bart's disease, parvovirus infection, and red cell antibodies were excluded. In view of the marked increase in erythroblasts at various stages of erythropoiesis, the diagnosis of CDA was suspected. We screened the couple for previously reported KLF1 gene mutations, showing that the mother was heterozygous for the c.525_526insCGGCGCC, p.Gly176Argfs*179 mutation, and her husband heterozygous for c.1012C>A, p.Pro338Thr mutation. The fetus was a compound heterozygote for these two KLF1 mutations. After counseling, repeated intrauterine transfusions were given at 27, 29, and 34 weeks' gestation; the hydrops fetalis was resolved. The baby was delivered at 34 weeks' gestation and required monthly blood transfusions but was otherwise thriving. Bone marrow aspiration at 10 months of age showed the features of ineffective erythropoiesis, compatible with CDA. In conclusion, hydrops fetalis can rarely be due to CDA associated with a compound heterozygous mutation for KLF1 gene mutations, and be managed by repeated intrauterine transfusions. Our present report adds to the wide clinical spectrum of KLF1 mutations.

Patient perception and knowledge on total joint replacement surgery.

OBJECTIVES: To study patients' perceptions and knowledge about total joint replacement surgery. DESIGN; Cross-sectional survey. SETTING; University teaching hospital, Hong Kong. PATIENTS: Three hundred consecutive patients with the diagnosis of osteoarthritis or inflammatory arthritis attending the out-patient clinic from June 2010 to May 2011. MAIN OUTCOME MEASURES: Patients' knowledge and how they got the knowledge about total joint replacement surgery, and concerns about the outcome of such operations. RESULTS: Whilst 94% of the patients knew about total joint replacement surgery, 77% obtained such knowledge from their friends and relatives. The three most common concerns related to this type of operation were whether they might: be wheelchair bound after surgery (64%), need to be taken care of by others for more than 3 months (61%), and have post-surgery complications (54%). Most of them recognised the advantages of the surgery, 82% knew about good pain relief after surgery, and 87% realised that total joint replacement surgery could improve their mobility. Patients did not have a realistic idea regarding the survival of the prosthesis; 41% thought the prosthesis might last for less than 10 years and 34% had no idea about its longevity. CONCLUSION; Patients did recognise the advantages of total joint replacement surgery in treating arthritis. However, they had many concerns about its outcome that warrant clarification. Public education on these aspects is necessary to address concerns, and may be achieved in cooperation with the media.

Toxic effects of two brominated flame retardants BDE-47 and BDE-183 on the survival and protein expression of the tubificid Monopylephorus limosus.

The toxic effects of two brominated diphenyl ethers (BDE), BDE-47, and BDE-183, on a benthic oligochaete tubificid, Monopylephorus limosus were studied under laboratory conditions. Investigated responses included survival, growth, and protein expression profiles, at BDE concentrations of 1, 10, 100, and 700 ng/g on a dry soil weight basis, with isooctane as the carrier solvent. Body weight losses among treatments were insignificant after 8 weeks of exposure. The 8-wk LC(50) of BDE-47 and -183 were 2311 and 169 ng/g, respectively. By applying multivariate analysis techniques, protein expression patterns were compared and correlated with stressful sources of long-term culture, carrier solvent, BDE-47 and -183. The treatment of 8-wk 100 ng/g BDE-47 was most closely clustered to the 10 ng/g BDE-183 treatment, based on the 40 examined protein spots. This indicated that BDE-183 was more potent to M. limosus, than was BDE-47. The 2-wk and 8-wk controls clustered into different groups indicating the occurrence of physiological changes due to long-term laboratory culture. Additionally, solvent effect was shown by grouping the isooctane carrier to different clusters. With further characterization by principle component analysis, it was found that the separation was mainly contributed by the 2nd principal-component. And, the primarily inhibitory variation was at spots 2 (UMP-CMP kinase) and 40 (plasma retinol-binding protein precursor) in the 8-wk groups. On the contrary, protein spots 16 (cell division control protein 2 homolog) and 24 (mitochondrial DNA mismatch repair protein) showed stimulatory variation. In all, the observed proteomic responses suggest that BDEs disrupted metabolic function in M. limosus and multivariate analysis tool offers significant potential for the assessment of various stress sources at biochemical level.

Imageless computer navigation in total knee arthroplasty.

OBJECTIVES: To study the difference in clinical and radiological outcomes between imageless computer-navigated and the conventional technique for performing total knee arthroplasty. DESIGN: Prospective case-control study. SETTING: University teaching hospital, Hong Kong. PATIENTS: Forty-seven patients with imageless computer-navigated total knee arthroplasty were matched with 47 patients with total knee arthroplasty using conventional technique over the period 2003 to 2007. MAIN OUTCOME MEASURES: Postoperative radiological alignment, tourniquet time, Knee Society knee score and functional score, and range of motion. RESULTS: The femoral anteroposterior, tibial anteroposterior, overall anteroposterior alignment of the lower limb, and lateral femoral lateral flexion angle had significantly less deviation from neutral alignment in those having computer-assisted total knee arthroplasty than conventional total knee arthroplasty. The former had significantly fewer outliers (>3 degrees from neutral alignment) than the latter, in both the coronal and sagittal planes of the femoral and tibial sides. The mean tourniquet time was significantly longer in the former (111 minutes) than in those having a conventional arthroplasty (98 minutes). There was no tracker/pin tract complication or wound infection in either group. CONCLUSION: Computer-assisted navigation can give a better alignment than the conventional technique, but the tourniquet time was significantly longer. Computer-assisted navigation surgery can help the surgeon in determining limb alignment during the operation.

Arthroscopy-assisted computer navigation in high tibial osteotomy for varus knee deformity.

PURPOSE: To assess the accuracy of knee alignment after high tibial osteotomy (HTO) for varus knee deformity using arthroscopy-assisted computer navigation. METHODS: Six men and 4 women aged 47 to 53 (mean, 49) years underwent medial open wedge HTO for varus knee deformity and medial unicompartmental osteoarthritis using arthroscopy-assisted computer navigation with fluoroscopy. Patients were followed up for a mean of 23 (range, 11-32) months. Intra- and post-operative leg alignments were compared. RESULTS: The mean postoperative coronal plane alignment was 2.7 (range,1-4) degree valgus; the mean deviation from intra-operative computer images was one (range, 0.1-1.9) degree; 5 knees had less valgus in the postoperative radiographs than the intra-operative computer images. CONCLUSION: Despite being more technically demanding, time consuming, and costly, arthroscopy-assisted computer navigation is safe, accurate, and reliable for HTO.

Pseudoaneurysm of the geniculate artery following total knee arthroplasty: a report of two cases.

We report 2 cases of pseudoaneurysm of the geniculate artery after a total knee arthroplasty (TKA). The first one was located in the superomedial geniculate artery and resolved after compression dressing and warfarin cessation. The second one was located in the superolateral geniculate artery and was successfully treated with transarterial embolisation. There was no recurrence in both cases. The rare occurrence and delayed presentation of pseudoaneurysms pose a diagnostic challenge. A high index of suspicion is required to make the diagnosis. Early duplex Doppler ultrasonography is recommended when patients present with atypical knee pain and prolonged swelling after a TKA.

Precision tumour resection and reconstruction using image-guided computer navigation.

The use of a navigation system in musculoskeletal tumour surgery enables the integration of pre-operative CT and MRI images to generate a precise three-dimensional anatomical model of the site and the extent of the tumour. We carried out six consecutive resections of musculoskeletal tumour in five patients using an existing commercial computer navigation system. There were three women and two men with a mean age of 41 years (24 to 47). Reconstruction was performed using a tumour prosthesis in three lesions and a vascularised fibular graft in one. No reconstruction was needed in two cases. The mean follow-up was 6.9 months (3.5 to 10). The mean duration of surgery was 28 minutes (13 to 50). Examination of the resected specimens showed clear margins in all the tumour lesions and a resection that was exactly as planned.

Effect of drain pressure in total knee arthroplasty.

PURPOSE: To study the effect of drain suction pressure on drainage volume, decrease in haemoglobin level, blood transfusion, and wound complications following total knee arthroplasty. METHODS: Primary total knee arthroplasty for degenerative osteoarthritis was performed in 60 (49 female and 11 male) patients. Patients were randomised for high-pressure (600 mm Hg) or low-pressure (350 mm Hg) postoperative suction drainage. Drain output was recorded daily and the drain removed after 48 hours. Postoperative haemoglobin level was measured on the evening of the operation day and on postoperative day 2. RESULTS: The high-pressure group had a significantly higher drainage volume and decrease in haemogloblin level than the low-pressure group. However, there was no significant difference between groups in the transfusion rate, number of units of blood transfused, wound discharge, or Knee Society knee and function scores. No wound infection was detected in any patient. CONCLUSION. Low-pressure suction drainage results in less blood loss without a significant increase in wound complications.

Multiple bioimaging modalities in evaluation of an experimental osteonecrosis induced by a combination of lipopolysaccharide and methylprednisolone.

AIMS: The present study employed both static and dynamic imaging modalities to study both intra- and extravascular events attributing to steroid-associated osteonecrosis (ON) using an experimental protocol with a single low-dose lipopolysaccharide (LPS) injection and subsequently three injections of high-dose methylprednisolone (MPS). METHODS: Fourteen 28-week-old male New Zealand white rabbits received one intravenous injection of LPS (10 microg/kg). 24 h later, three injections of 20 mg/kg of MPS were given intramuscularly at a time interval of 24 h. Additional 6 rabbits were used as controls. Dynamic MRI was performed on bilateral femora for local intraosseous perfusion before and after LPS injection. Blood samples were collected for hematological examinations before and after LPS injection. Bilateral femora were dissected and decalcified for microCT-based microangiography. ON lesion, intravascular thrombus and extravascular marrow fat cell size were examined histopathologically. RESULTS: Intravascular thrombus was observed in all ON rabbits. Extravascular marrow fat cell size was significantly increased in ON rabbits than that of the controls (P<0.05). Compared to baseline, a significant decrease in ratio of tissue-type plasminogen activator/plasminogen activator inhibitor 1, activated partial thromboplatin time and a significant increase in ratio of low-density lipoprotein/high-density lipoprotein were only found in ON rabbits (P<0.05). Dynamic MRI showed a significant decrease in the perfusion index 'maximum enhancement' in the ON rabbits (P<0.05), and microCT-based microangiography showed blocked stem vessels in ON samples. Overall, 93% of the rabbits (13/14) developed ON, and no rabbits died throughout the experiment period. CONCLUSION: Both intra- and extravascular events were found attributing to the steroid-associated ON based on our experimental protocol with a single low-dose LPS injection and subsequent three injections of high-dose MPS. Both high ON incidence and no mortality in rabbits treated with this inductive protocol suggested its effectiveness for future studies on evaluation of therapeutic efficacy of interventions developed for prevention of steroid-associated ON.

Enhanced soft tissue repair using locking loop stitch after posterior approach for hip hemiarthroplasty.

Hemiarthroplasty of the hip for displaced fracture of the femoral neck (including Austin-Moore and Thompson arthroplasties) frequently is performed by orthopaedic surgeons. The posterior approach is used despite the slight increase in risk of postoperative dislocation. The outcome after dislocation can be disastrous. We tried to prevent this complication by repairing the posterior capsule and the short external rotators (piriformis, superior and inferior gemellus, obturator internus, and upper part of quadratus femoris) using locking loop stitch as described by Krackow. From January 1998 to April 1999, 205 hips were operated on and followed up for >3 months; no dislocation was found. Using the past records as the comparative group, 28 posterior dislocations (1.9%) were found in 1,483 hip hemiarthroplasties using the posterior approach (P <.05 using exact probability test). Enhanced soft tissue repair with locking loop stitch is an effective way to reduce the incidence of dislocation after hip hemiarthroplasty using the posterior approach.

Seasonal variation of hip fracture at three latitudes.

We studied the seasonal variation of hip fracture admissions at three different latitudes: Scotland (56 degrees North; 54,399 admissions); Shatin, Hong Kong (22 degrees North; 4180 admissions); and Auckland, New Zealand (36 degrees South; 2257 admissions). We calculated the extent of seasonal variation (amplitude) and the time of year of the peak value (acrophase) by fitting a sine curve to monthly data using cosinor analysis. A significant seasonal variation was found in all three countries, at a high level in Scotland (p < 0.01) and Hong Kong (p < 0.001), but just significant in New Zealand (p < 0.05). The extent of the seasonal change was very similar in Scotland and New Zealand, but, as expected, the peak in New Zealand (early September) was approximately six months ahead of Scotland (mid February). In Hong Kong, the amplitude was three times greater than in Scotland and the peak occurred a month earlier. There is neither snow nor ice in Hong Kong, and this provides powerful evidence against a major influence of conditions underfoot causing extra falls in winter. In Scotland there was a significant increase in the proportion of deaths in winter as compared to summer. The Scotland/Hong Kong amplitude difference is striking, but it is unknown whether this has a genetic or environmental explanation. The cause of seasonal death difference to a given injury is also unknown. Possible mechanisms are discussed, but the purpose is to report two new epidemiological features, without wild speculative hypotheses. The findings should be viewed as leads to further epidemiological, clinical and more basic research.

Osteonecrosis of the femoral head treated with cementless total hip arthroplasty. A comparison with other diagnoses.

Primary cementless Porous Coated Anatomic total hip arthroplasty was carried out in 36 hips in 29 patients with osteonecrosis (ON) patients and in 36 hips in 33 patients without ON. The ON was alcohol related in 11. steroid induced in 5, post-traumatic in 4, and idiopathic in 16 patients. The average follow-up period was 6 years. Clinical evaluation demonstrated 77.8% excellent or good results in the patients with ON, with the average Harris hip scores improved from 36.8 to 83.5. No revision of a prosthesis has yet been performed in the patients with ON. The patients with alcohol-related and steroid-induced ON had inferior clinical results when compared with the patients without ON. There were no statistically significant differences in the clinical results between the patients with post-traumatic or idiopathic ON and the patients without ON.

Experience with primary exeter total hip arthroplasty in patients with small femurs. Review at average follow-up period of 6 years.

One hundred twelve hips in 101 Chinese patients received a primary cemented Exeter total hip arthroplasty (Howmedica, Hong Kong). Average age was 65 years. The most common diagnosis was avascular necrosis. Average follow-up period was 6 years (range, 3 years to 9 years, 6 months). The Harris hip score improved from a preoperative average of 41.2 to 82.2 at the last follow-up visit. Stem subsidence within the cement mantle occurred in 9% of the cases, and none of these stems had other evidence of loosening. Three hips in two patients were revised because of loosening at 5 to 8 years after surgery. Because of the small size of the femurs, stem oversizing was common. Oversizing of the stem and an incomplete cement mantle might account for the early loosening. Stems of a smaller size should be made available to this population.

Osteomyelitis of the spine due to Salmonella infection--conservative treatment with quinolone: a case report.

Although osteomyelitis due to Salmonella infection is known to be associated with sickle cell anemia, various hemoglobinopathies and immune suppressive states, it may also occur in normal hosts. A 16-year-old Chinese boy without sickle cell disease or any other condition that would compromise the immune system had osteomyelitis of the lumbar spine caused by Salmonella enteritidis. The condition was treated conservatively with ciprofloxacin (quinolone group). This may be the first reported case in which a patient with spinal osteomyelitis due to Salmonella infection, who was otherwise healthy, was successfully treated nonoperatively with quinolone.

Uncemented porous-coated anatomic total hip replacement in Chinese patients.

Primary uncemented Porous-Coated Anatomic total hip replacement was carried out in 72 hips in 62 Chinese patients. Their average age was 50 years and the average follow up was 3 1/2 years. The most common diagnosis was avascular necrosis. The average preoperative Harris score of 36.3 points improved to 83.2 at the last follow up. The pain score improved from 13.7 out of 44 to an average of 42. Seven of 8 hips with thigh pain had an inadequately fitting stem which had subsided. Only one cup was revised because of a technical error and one femoral component for loosening. Uncemented Porous-Coated Anatomic total hip replacement gave good early results in Chinese patients.