Laminar flow does not affect risk of prosthetic joint infection after primary total knee replacement in Asian patients.

BACKGROUND: The role of laminar flow (LAF) is contradictory with several studies failing to replicate risk reduction. The 2016 World Health Organization guidelines identified this lack of good comparative studies. AIM: To analyse the use of LAF and the incidence of prosthetic joint infections (PJIs) in Asian patients undergoing total knee replacement (TKR). METHODS: Patients who underwent standard cemented posterior-stabilized TKR from 2004 to 2014 were reviewed from a prospectively collected single-surgeon database. Revision, traumatic and/or inflammatory cases were excluded. The type of airflow used was identified. The technique and surgical protocol for all procedures were similar. Tourniquets and inserted drains were routinely used. Patellar resurfacing was not performed. Patients were followed up at the outpatient clinics at regular intervals up to two years. At each visit, the patient was assessed for the occurrence of PJI. FINDINGS: Of the 1028 procedures, 453 (44.1%) were performed in an LAF operating theatre (OT) whereas 575 (55.9%) were performed in a non-LAF OT. There were no significant differences between the two groups in terms of age, gender, or side of procedure. The overall incidence of PJI was 0.6% (N = 6). Three (50%) occurred in an LAF OT whereas three (50%) occurred in a non-LAF OT. This was not statistically significant. CONCLUSION: Laminar flow systems are costly to procure and maintain. With modern aseptic techniques, patient optimization, and use of prophylactic antibiotics, laminar flow does not appear to further reduce risk of PJI in Asian patients after TKR.

The developmental dynamics of gait maturation with a focus on spatiotemporal measures.

Gait analysis is recognised as a powerful clinical tool for studying relationships between motor control and brain function. By drawing on the literature investigating gait in individuals with neurological disorders, this review provides insight into the neural processes that contribute to and regulate specific spatiotemporal sub-components of gait and how they may mature across early to late childhood. This review also discusses the roles of changing anthropomorphic characteristics, and maturing sensory and higher-order cognitive processes in differentiating the developmental trajectories of the sub-components of gait. Importantly, although studies have shown that cognitive-gait interference is larger in children compared to adults, the contributing neurocognitive mechanisms may vary across age groups who have different types of attentional or cognitive vulnerabilities. These findings have implications for current models of gait maturation by highlighting the need for a dynamic model that focuses on the integration of various factors that contribute to gait though experience and practice. This is essential to elucidating why gait and other motor deficits are often contiguous with cognitive neurodevelopmental disorders.

The Association Between Bullous Pemphigoid and Neurological Disorders in A Selected Malaysian Population.

BACKGROUND: An association of bullous pemphigoid with neurological disorders has been reported. The objectives of this study were to review the clinical characteristics of patients with bullous pemphigoid and compare the association between bullous pemphigoid and various neurological disorders and comorbidities. METHODS: This was a retrospective case-control study involving 43 patients with bullous pemphigoid and 43 age-, sex- and ethnicity-matched controls. RESULTS: There was a statistically significant association between bullous pemphigoid and neurological disorders [Odds Ratio (OR) = 3.5, 95% Confidence Interval (CI) 1.3 to 9.2, p=0.011 and adjusted OR=3.5, 95% CI 1.2-10.3, p=0.026], in particular for dementia (p=0.002). Although stroke was more common among patients with bullous pemphigoid, this association was not statistically significant with OR of 1.9 (95% CI 0.7 to 5.2) and adjusted OR of 2.1 (95% CI 0.6 to 7.2). Similarly both ischaemic stroke (OR 1.5, 95% CI 0.5 to 4.2) and haemorrhagic stroke (OR 1.5, 95% CI 0.2 to 9.7) were more common. Other neurological disorders more common among patients with bullous pemphigoid were Parkinson's disease and epilepsy. Dyslipidaemia was significantly less common among patients with bullous pemphigoid (OR 0.4, 95% CI 0.1 to 0.9, p=0.033). CONCLUSION: A combination of an inflammatory process, prothrombotic state and endothelial activation leads to an increased frequency of neurological disorders among patients with bullous pemphigoid. Thus, a holistic approach to patient care, including screening for dementia and control of comorbidities, should be practised as bullous pemphigoid affects more than just the skin.

Oestradiol is a protective factor for non-alcoholic fatty liver disease in healthy men.

Visceral fat is a risk factor for non-alcoholic fatty liver disease (NAFLD). A reduction in sex hormones is associated with increased abdominal fat. Thus, we investigated whether reduced testosterone (T) or oestradiol (E2) levels in men are associated with NAFLD and central obesity. The study involved a survey of 1,882 men between 20 and 60 years of age. We detected hepatic fat infiltration by ultrasound. Early morning serum was analyzed for total testosterone (TT), E2, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Free testosterone (FT) was calculated using the Vermeulen method. In the studied population, the prevalence of NAFLD, FSH, LH and SHBG increased with age, TT and FT declined with age, and E2 remained stable. However, in the NAFLD group, TT remained stable, FT and E2 declined, and hepatic fat infiltration increased (P < 0.001 for both). Using multivariate analysis, a correlation was found between E2 and NAFLD, with an odds ratio of 0.954 (95% confidence interval: 0.946-0.967). E2 is one of the protective factors against NAFLD in healthy men. T has no significant correlation with NAFLD. Further investigation would be required to assess the clinical consequences of reduced E2 in men with NAFLD, particularly for men whose TT remained stable.

Arthroscopic Bankart repair for traumatic anterior shoulder instability with the use of suture anchors.

INTRODUCTION: The arthroscopic method offers a less invasive technique of Bankart repair for traumatic anterior shoulder instability. The results continue to improve with the advancements made in instrumentation and technique. This study aims to evaluate the outcome of arthroscopic Bankart repair with the use of suture anchors for cases that were followed-up for at least two years from the date of surgery. METHODS: This was a consecutive series of 40 shoulders in 37 patients who underwent arthroscopic Bankart repair with suture anchor. The mean age at the time of operation was 26.3 years. The patients were assessed with two different outcome measurement tools (the University of California at Los Angeles [UCLA] shoulder rating scale and simple shoulder test [SST] score). The mean duration of follow-up was 30.2 months. The recurrence rate, range of motion, and postoperative function were evaluated. RESULTS: The two shoulder scores significantly improved after surgery (p-value is less than 0.05). According to the UCLA scale, 37 shoulders (92.5 percent) had excellent or good scores, one shoulder (2.5 percent) had a fair score, and two (five percent) had poor scores. All 12 components of SST showed improvement, which was statistically significant. Overall, the rate of postoperative recurrence was 7.5 percent (three shoulders). All patients either maintained or demonstrated improvement of range of motion. There was no loss of external rotation range of motion postoperatively. CONCLUSION: Arthroscopic Bankart repair with the use of suture anchors is a reliable treatment method that can provide a good clinical outcome with excellent postoperative shoulder motion and low recurrence rate.

Integrating temporal difference methods and self-organizing neural networks for reinforcement learning with delayed evaluative feedback.

This paper presents a neural architecture for learning category nodes encoding mappings across multimodal patterns involving sensory inputs, actions, and rewards. By integrating adaptive resonance theory (ART) and temporal difference (TD) methods, the proposed neural model, called TD fusion architecture for learning, cognition, and navigation (TD-FALCON), enables an autonomous agent to adapt and function in a dynamic environment with immediate as well as delayed evaluative feedback (reinforcement) signals. TD-FALCON learns the value functions of the state-action space estimated through on-policy and off-policy TD learning methods, specifically state-action-reward-state-action (SARSA) and Q-learning. The learned value functions are then used to determine the optimal actions based on an action selection policy. We have developed TD-FALCON systems using various TD learning strategies and compared their performance in terms of task completion, learning speed, as well as time and space efficiency. Experiments based on a minefield navigation task have shown that TD-FALCON systems are able to learn effectively with both immediate and delayed reinforcement and achieve a stable performance in a pace much faster than those of standard gradient-descent-based reinforcement learning systems.

Posterior fracture-dislocation of the humeral head treated without the use of metallic implants.

Posterior fracture-dislocation of the humeral head is an uncommon injury, usually associated with seizures, electrocution injury and high-impact trauma. Prompt diagnosis and treatment are important to prevent avascular necrosis of the humeral head. Various methods to treat such injury have been described. We report a 34-year-old man who had a four-part humeral head fracture with concomitant posterior dislocation that was treated with open reduction and internal fixation with non-absorbable polyester sutures. The diagnosis and operative techniques are described and factors influencing our choice of management are discussed. A review of the literature is also included.

Missed posterior fracture-dislocation of the humeral head following an electrocution injury to the arm.

Posterior dislocation of the shoulder is a rare and commonly missed injury. While prompt diagnosis and treatment is important to prevent untoward sequelae, it is often diagnosed and treated too late. The first reported case of a posterior fracture-dislocation of the humeral head following a domestic electrocution accident in Singapore is described in a 52-year-old man. The injury was missed by several doctors before a humeral head replacement was done. The diagnostic pitfalls and management of this injury and ways to avoid a missed or delayed diagnosis are discussed.

Ureteroscopy for pediatric urolithiasis: an evolving first-line therapy.

OBJECTIVES: To present in a retrospective report a contemporary series of patients aged 14 years and younger who were treated for stones with ureteroscopy at our institution from 1991 to 2002. With the improvement and miniaturization of ureteroscopes and ancillary instruments, the endoscopic treatment of renal and ureteral calculi in children has become more feasible. METHODS: A retrospective chart review was performed of 23 patients aged 14 years and younger who had undergone ureteroscopy for the treatment of ureteral or renal calculi at our institution. RESULTS: A total of 27 stones were treated in 23 patients. Of the 27 stones, 18 were in the distal ureter, 5 in the mid ureter, 2 in the proximal ureter, and 2 in the renal pelvis. Ureteral dilation was performed in 4 (17.4%) of the 23 patients. The lithotripsy modalities used were holmium:yttrium-aluminum-garnet laser in 16 (69.6%), electrohydraulic lithotripsy in 3 (13%), a combination of holmium laser and electrohydraulic lithotripsy in 2 (8.7%), and basket extraction alone in 2 (8.7%) of 23 patients. Ureteral stents were placed in 21 (91.3%) of 23 patients. The average operative time was 46.9 minutes (range 15 to 92). In 21 (91.3%) of 23 patients, postoperative imaging was available and revealed that 20 (95.2%) of the 21 patients were rendered stone free. Two patients were lost to follow-up. No intraoperative complications occurred. One patient was treated postoperatively with intravenous antibiotics for transient fever. CONCLUSIONS: Ureteroscopy is safe and effective in the management of ureteral and renal calculi in children. In our institution, it has emerged as a valid first-line therapy for the treatment of pediatric urolithiasis.

Assessment of blood-induced cartilage damage in rabbit knees using scanning electron microscopy.

PURPOSE: To investigate the harmful effects of a single episode of intra-articular bleeding on articular cartilage of rabbit knees using scanning electron microscopy. METHODS: Autologous blood was injected into the right knee joints of 18 New Zealand white rabbits. Surface and cellular damages were examined by the scanning electron microscope (n=9) and light microscope (n=34), respectively. The injected right knees were then compared with the corresponding control left knees at one, 3, and 6 weeks after the blood injection. RESULTS: The articular surface of the injected knees turned uniformly rough with multiple pits after one week. Maximal changes with elevations and depressions were observed at 3 weeks. These changes reversed at 6 weeks with the irregularities smoothing out. A similar pattern of transient cartilage damage was noted histologically. CONCLUSION: Both scanning electron microscopic and light microscopic findings suggest that a single episode of intra-articular bleeding leads to articular cartilage damage but this appears to be reversible. Our findings of transient damage to the articular cartilage suggest that there is no need for intra-articular evacuation and washout following an acute episode of haemarthrosis.

Results of shockwave lithotripsy for pediatric urolithiasis.

BACKGROUND AND PURPOSE: Shockwave lithotripsy (SWL) is widely practiced in the management of pediatric urolithiasis. However, the efficacy, need for ancillary procedures, and treatment-related complications are not as clearly defined as in the adult population. We reviewed the outcomes of SWL in the pediatric population at our lithotripsy unit. PATIENTS AND METHODS: A retrospective review of all patients

Long-term results of high-power holmium laser vaporization (ablation) of the prostate.

OBJECTIVE: To present the 7-year follow-up data from the initial series of patients treated by holmium laser ablation of the prostate (HoLAP) for symptoms of benign prostatic hyperplasia at our institution. PATIENTS AND METHODS: In all, 79 patients underwent HoLAP in the initial series between September 1994 and May 1995. All patients were contacted by telephone and mail; those available for follow-up had their peak urinary flow rate, American Urological Association (AUA) symptom score, single-question quality-of-life (QoL) score and adverse events assessed. Patients were also assessed using the International Continence Society 'male short-form' (ICSmaleSF) questionnaire on lower urinary tract symptoms (LUTS). RESULTS: At a median follow-up of 89 months (7.4 years), 17 patients had died (21%), 28 could not be contacted or refused follow-up (35%), leaving 34 patients (43%) available for assessment. The mean (range) AUA score of the remainder was 10.0 (0-26), the maximum urinary flow rate 16.8 (5-35) mL/s and QoL score 2.1 (0-5). The mean ICSmaleSF voiding score was 5.8 and the mean incontinence score 3.2. The impact score of their current LUTS (QoL) was 0.68, implying a minimal effect. No patient required pads for incontinence. The reoperation rate was 15%, with one patient each undergoing transurethral resection or bladder neck incision, two undergoing holmium laser enucleation of the prostate and one having a bladder stone removed endoscopically. CONCLUSIONS: The long-term results of HoLAP were satisfactory in those patients who were available for the follow-up.

A randomized trial comparing holmium laser enucleation of the prostate with transurethral resection of the prostate for the treatment of bladder outlet obstruction secondary to benign prostatic hyperplasia in large glands (40 to 200 grams).

PURPOSE: Holmium laser enucleation of the prostate (HoLEP) is a surgical treatment for bladder outlet obstruction secondary to benign prostatic hyperplasia. HoLEP is a transurethral procedure that uses the holmium laser fiber (wavelength 2,140 nm) to dissect whole prostatic lobes off of the surgical capsule in retrograde fashion, while maintaining excellent hemostasis. The lobes are removed from the bladder by a purpose built transurethral morcellator, which means that large volume prostates can be enucleated endoscopically. We compared this procedure with transurethral prostate resection (TURP) in a randomized trial by evaluating outcomes in patients with a prostate volume of 40 to 200 ml on transrectal ultrasound. MATERIALS AND METHODS: A total of 61 patients with urodynamically proved bladder outlet obstruction secondary to benign prostatic hyperplasia were randomized to TURP or HoLEP. Perioperative parameters recorded included resectoscope, laser, electrocautery, morcellation and catheter time, hospital stay, bladder irrigation, volume blood transfusion the rate and resected tissue weight. Patients were followed 1, 3, 6 and 12 months postoperatively with peak urinary flow rate measurement and quality of life and American Urological Association symptom scores. Patients also underwent urodynamic assessment at 6 months with measurement of peak detrusor pressure at maximal flow, post-void residual volume and prostate volume by transrectal ultrasound. Continence, potency and all adverse events were recorded at each visit. RESULTS: HoLEP was superior to TURP in terms of mean catheter time (17.7 +/- 0.7 vs 44.9 +/- 10 hours) and hospital stay (27.6 +/- 2.7 vs 49.9 +/- 5.6 hours) but it required more time to perform (62.1 +/- 5.9 vs 33.1 +/- 3.7 minutes). More prostate tissue was removed in the HoLEP group (40.4 +/- 5.7 vs 24.7 +/- 3.4 gm). HoLEP was also superior to TURP in terms of relieving urodynamic obstruction at 6 months of followup (postoperative detrusor pressure at maximum flow 20.8 +/- 2.8 vs 40.7 +/- 2.7 cm H2O). HoLEP and TURP led to significant improvements in peak flow rates, symptom scores and quality of life scores compared with baseline and there was no significant difference between the 2 procedures with respect to these parameters at 12 months. Fewer adverse events were recorded in the HoLEP group. CONCLUSIONS: HoLEP is superior to TURP for relieving bladder outlet obstruction in men with benign prostatic hyperplasia. It allows more rapid catheter removal and hospital discharge. It requires more time to perform than TURP but more prostate tissue is removed, resulting in similar efficiency in tissue retrieval. HoLEP is equivalent to TURP in relieving men of lower urinary tract symptoms and in improving peak urinary flow rates at 12 months of followup.

Radiological classification of meniscocapsular tears of the anterolateral portion of the lateral meniscus of the knee.

In an arthroscopic-MRI correlation study of acute injuries to the knee it was found that anterolateral meniscocapsular separations of the lateral aspect of the knee were missed on MRI reporting. Eighty sports-related injuries of the knee were seen by experienced orthopaedic surgeons at the University of Malaya Medical Centre and at the National Sports Centre, Malaysia from January 1996 to July 1997. Fifty of the patients were suspected to have meniscal tears that were either lateral or medial on clinical examination and they were sent for MRI. Many of these patients were tertiary referrals. Magnetic resonance imaging examinations in 27 of the 50 patients were reported as not showing any intrasubstance or obvious meniscocapsular tears, but arthroscopy performed on them revealed anterolateral meniscocapsular tears of the lateral meniscus of varying degrees in nine of these patients. In retrospect the tears could be seen on MRI, and a pattern to the tears was noted and classified as follows. Type 0, normal; type 1, torn inferior or superior meniscocapsular attachment; type 2, both meniscofemoral and meniscotibial ligaments torn but with minimal separation of meniscus and capsule by fluid or synovitis; and type 3, marked separation of meniscus and capsule by fluid (> 3 mm). Ten patients who did not undergo arthroscopy for various personal and financial reasons underwent MRI which showed type 1 and type 2 tears, and were treated conservatively. These patients were all asymptomatic after 4-6 weeks with regard to clinical signs, suggesting a lateral meniscal tear. Magnetic resonance imaging therefore does reveal minor degrees of meniscocapsular tears anterolaterally when one understands the normal anatomy in this region.

Failed magnetic resonance imaging examinations due to claustrophobia.

A recognized cause of incomplete or cancelled MRI examinations is anxiety and claustrophobic symptoms in patients undergoing MR scanning. This appears to be a problem in many MRI centres in Western Europe and North America, where it is said to be costly in terms of loss of valuable scan time, and has led to researchers suggesting several anxiety-reducing approaches for MRI. To determine the incidence of failed MRI examination among our patients and if there are any associations with a patient's sex, age and education level, we studied claustrophobia that led to premature termination of the MRI examination in the University Malaya Medical Centre (UMMC) in 3324 patients over 28 months. The incidence of failed MRI examinations due to claustrophobia in the UMMC was found to be only 0.54%. There are associations between claustrophobia in MRI with the patients' sex, age and level of education. The majority of those affected were male patients and young patients in the 25-45-years age group. The patients' education level appears to be the strongest association with failed MRI examinations due to claustrophobia, where the majority of the affected were highly educated individuals. Claustrophobia in MRI is more of a problem among the educated individuals or patients from a higher socio-economic group, which may explain the higher incidence in Western European and North American patients.

Cascade ARTMAP: integrating neural computation and symbolic knowledge processing.

This paper introduces a hybrid system termed cascade adaptive resonance theory mapping (ARTMAP) that incorporates symbolic knowledge into neural-network learning and recognition. Cascade ARTMAP, a generalization of fuzzy ARTMAP, represents intermediate attributes and rule cascades of rule-based knowledge explicitly and performs multistep inferencing. A rule insertion algorithm translates if-then symbolic rules into cascade ARTMAP architecture. Besides that initializing networks with prior knowledge can improve predictive accuracy and learning efficiency, the inserted symbolic knowledge can be refined and enhanced by the cascade ARTMAP learning algorithm. By preserving symbolic rule form during learning, the rules extracted from cascade ARTMAP can be compared directly with the originally inserted rules. Simulations on an animal identification problem indicate that a priori symbolic knowledge always improves system performance, especially with a small training set. Benchmark study on a DNA promoter recognition problem shows that with the added advantage of fast learning, cascade ARTMAP rule insertion and refinement algorithms produce performance superior to those of other machine learning systems and an alternative hybrid system known as knowledge-based artificial neural network (KBANN). Also, the rules extracted from cascade ARTMAP are more accurate and much cleaner than the NofM rules extracted from KBANN.

Concept hierarchy memory model: a neural architecture for conceptual knowledge representation, learning, and commonsense reasoning.

This article introduces a neural network based cognitive architecture termed Concept Hierarchy Memory Model (CHMM) for conceptual knowledge representation and commonsense reasoning. CHMM is composed of two subnetworks: a Concept Formation Network (CFN), that acquires concepts based on their sensory representations; and a Concept Hierarchy Network (CHN), that encodes hierarchical relationships between concepts. Based on Adaptive Resonance Associative Map (ARAM), a supervised Adaptive Resonance Theory (ART) model, CHMM provides a systematic treatment for concept formation and organization of a concept hierarchy. Specifically, a concept can be learned by sampling activities across multiple sensory fields. By chunking relations between concepts as cognitive codes, a concept hierarchy can be learned/modified through experience. Also, fuzzy relations between concepts can now be represented in terms of the weights on the links connecting them. Using a unified inferencing mechanism based on code firing, CHMM performs an important class of commonsense reasoning, including concept recognition and property inheritance.

Percutaneous transluminal angioplasty. An ineffective approach to the failing vascular access.

A prosthetic arteriovenous (AV) fistula is often necessary in patients with chronic renal failure who lack suitable venous anatomy for the construction of an autogenous AV access. Not infrequently, these conduits fail as a result of neointimal hyperplasia obstructing the outflow tract at the venous anastomosis. Six patients underwent one or more attempts at balloon dilation of an anastomotic stenosis. Grafts had either thrombosed, exhibited poor arterial inflow, or developed high venous pressures. Eight of ten dilations were outright failures, while two dilations each provided an additional three months of graft function before surgical revision became necessary. We conclude that percutaneous transluminal angioplasty is of very limited value as a salvage procedure in the failing synthetic vascular access, and should be attempted only as a possible temporizing measure in those individuals in whom definitive surgical correction must be delayed.

Characterization of the glycogen synthase D found in liver of the adrenalectomized fasted rats.

We have previously shown that the synthase D (UDPglucose:glycogen 4-alpha-D-glucosyltransferase, EC 1.4.1.11) present in the liver of the adrenalectomized fasted rat was not converted to synthase I by synthase phosphatase from normal animals, suggesting the presence of a non-substrate form of synthase D (Tan, A.W.H. and Nuttall, F.Q. (1976) Biochim. Biophys. Acta 445, 118--130). The enzymatic properties of this synthase D have now been examined. Using optimal assay conditions, the total amount of synthase D activity in the adrenalectomized fasted rats was similar to that of normal fed rats when 1% glycogen was included in the homogenizing buffer. However, the two enzymes appeared to have different affinities for the substrate, UDPglucose and the modifier, glucose-6-P. The changes in kinetic properties were not due to differences in glycogen or to a dialyzable modifier in the extracts. Synthase D from adrenalectomized fasted and from normal fed rats was partially purified. After DEAE-cellulose chromatography, modification appeared to have occurred such that the enzyme from the adrenalectomized fasted rat had properties similar to that of the normal fed rat. The enzymes were cold-labile, had different properties from enzymes in the crude extract and they were both converted to synthase I by synthase phosphatase. We conclude from these studies that the phosphorylation site in the synthase is in a flexible region of the protein. Changes in the ability of the synthase D to interact and be dephosphorylated by synthase phosphatase can occur readily in vivo and in vitro. The molecular basis for the modification remains unknown.