Publications by authors named "Aaron Ng"

16 Publications

  • Page 1 of 1

Dual mobility versus unipolar total hip arthroplasty for neck of femur fractures : a single centre study.

Acta Orthop Belg 2021 Mar;87(1):35-39

Current national guidelines (NICE) recommends that all medically fit, independently-mobile patients without cognitive impairment receive a total hip arTHAoplasty(THA) for displaced intracapsular neck of femur (NOF) fractures. Dislocation is a concern(2-10%). Dual mobility cups have been suggested to address this complication. Our study sets out to compare dislocation rates between dual mobility cups versus unipolar cups. We performed a retrospective single centre multiple surgeon study of all THAs performed for NOFs between January 2012 and May 2018. A total of 322 total hip replacements (127 dual mobility and 195 unipolar ; Age range of patients, 29 to 91, mean 70 years) were identified for analysis using a database. Data was obtained from electronic patient records and radiographs. 12 patients sustained a dislocation of their THA out of our 322 patients. Of these, 10 dislocations occurred in the unipolar group (5.13%). From the dual mobility cups, 2 had dislocations(1.57%), both with a 28mm head. Both of these dislocations were in alcohol dependent patients with increased susceptibility to falls. Statistical analysis of our data was performed using chi-squared test (p value = 0.0723) In 'Getting It Right First Time' (GIRFT), the authors recommend that all patients that sustain a NOF fracture meeting the criteria of a THA to be offered a dual mobility acetabular cup to reduce the risk of dislocation. The cost of the dual mobility acetabular cup is offset from the cost of overall revision surgery. Limitations of our study are its retrospective nature and selection bias.
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March 2021

Conditional transparency: Differentiated news framings of COVID-19 severity in the pre-crisis stage in China.

PLoS One 2021 24;16(5):e0252062. Epub 2021 May 24.

Department of Communications and New Media, National University of Singapore, Singapore, Singapore.

Transparency of Chinese media coverage became an international controversy when the COVID-19 outbreak initially emerged in Wuhan, the eventual crisis epicenter in China. Unlike studies characterizing mass media in authoritarian contexts as government mouthpieces during a crisis, this study aims to disaggregate Chinese media practices to uncover differences in when, where, and how the severity of COVID-19 was reported. We examine differences in how media institutions reported the severity of the COVID-19 epidemic in China during the pre-crisis period from 1 January 2020 to 20 January 2020 in terms of both the "vertical" or hierarchical positions of media institutions in the Chinese media ecosystem and the "horizontal" positions of media institutions' social proximity to Wuhan in terms of geographical human traffic flows. We find that the coverage of crisis severity is negatively associated with the media's social proximity to Wuhan, but the effect varies depending on the positional prominence of a news article and situation severity. Implications of the institutions' differentiated reporting strategies on future public health reporting in an authoritarian context are also discussed.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252062PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8143385PMC
June 2021

Using the West Midlands CONCERT to characterise regional incidence of acute-onset post cataract surgery endophthalmitis.

Eye (Lond) 2021 Jun 1;35(6):1730-1740. Epub 2020 Sep 1.

Birmingham and Midland Eye Centre, Birmingham, UK.

Background: Whilst research and innovation is embedded within the UK's National Health Service (NHS) constitution, Doctors-in-training have little opportunity to contribute to designing, leading and recruiting into clinical trials or cohort studies. We formed the West Midlands Collaborative Ophthalmology Network for Clinical Effectiveness & Research by Trainees (The West Midlands CONCERT) and undertook a characterisation of post cataract surgery endophthalmitis as a proof-of-concept study to test the feasibility of the CONCERT model.

Methods: Doctors-in-training formed a collaborative working group to test the concept of delivering a pan-regional clinical effectiveness study across multiple hospital sites by performing retrospective analyses of post cataract endophthalmitis over a 6-year period.

Results: Overall, 157,653 cataract surgeries were performed by participating centres accredited to deliver the Royal College of Ophthalmologists training curriculum. Thirty-eight cases of post cataract endophthalmitis were identified, giving an incidence of 2.41 per 10,000 cases (0.0241%). A further 15 endophthalmitis cases presented who had surgery in non-training centres, giving a total of 53 cases. The most common organisms were S. epidermidis (14 (51.9%)) and P. aeruginosa (5 (18.5%)). Anterior-chamber and vitreous sampling yielded positive culture in 33.3% (6/18) and 50.9% (27/53), respectively. At 6 months follow-up, 19 (51.4%) patients achieved visual acuities of ≤0.5 LogMAR. Repeat intravitreal injections (11 (20.8%)) and vitrectomy (n = 22 (41.5%)) were not associated with better outcomes.

Conclusions: Using post cataract endophthalmitis as a pilot cohort, this study highlights the feasibility of using the CONCERT model for studies across multiple sites. A UK-CONCERT could provide a powerful infrastructure enabling characterisation of patient cohorts and a platform for high-quality interventional studies, improving patient care.
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http://dx.doi.org/10.1038/s41433-020-01158-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8169918PMC
June 2021

Sustained release of decorin to the surface of the eye enables scarless corneal regeneration.

NPJ Regen Med 2018 21;3:23. Epub 2018 Dec 21.

2School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT UK.

Disorganization of the transparent collagenous matrix in the cornea, as a consequence of a variety of infections and inflammatory conditions, leads to corneal opacity and sight-loss. Such corneal opacities are a leading cause of blindness, according to the WHO. Public health programs target prevention of corneal scarring, but the only curative treatment of established scarring is through transplantation. Although attempts to minimize corneal scarring through aggressive control of infection and inflammation are made, there has been little progress in the development of anti-scarring therapies. This is owing to eye drop formulations using low viscosity or weak gelling materials having short retention times on the ocular surface. In this study, we report an innovative eye drop formulation that has the ability to provide sustained delivery of decorin, an anti-scarring agent. The novelty of this eye drop lies in the method of structuring during manufacture, which creates a material that can transition between solid and liquid states, allowing retention in a dynamic environment being slowly removed through blinking. In a murine model of , applying the eye drop resulted in reductions of corneal opacity within 16 days. More remarkably, the addition of hrDecorin resulted in restoration of corneal epithelial integrity with minimal stromal opacity endorsed by reduced α-smooth muscle actin (αSMA), fibronectin, and laminin levels. We believe that this drug delivery system is an ideal non-invasive anti-fibrotic treatment for patients with microbial keratitis, potentially without recourse to surgery, saving the sight of many in the developing world, where corneal transplantation may not be available.
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http://dx.doi.org/10.1038/s41536-018-0061-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6303295PMC
December 2018

Multi-Layer Filters: Adsorption and Filtration Mechanisms for Improved Separation.

Front Chem 2018 12;6:417. Epub 2018 Sep 12.

Chemical Engineering Department, Bioresource Processing Research Institute of Australia, Monash University, Clayton, VIC, Australia.

Filters made of cellulose fiber and perlite particles were prepared using a wet laying papermaking technique. Polyamide-amine-epichlorohydrin (PAE) was added to provide wet strength. Filters were prepared at two different total basis weights of 200 and 400 grams per square meter (gsm). Single and multi-layered filters were structured for each total basis weights. The effect of total basis weights and multi-layered structure on methylene blue adsorption and silicon dioxide (SiO) particle filtration was investigated. Methylene blue adsorption was performed in two modes: constant pressure and constant flow rate. In both operation modes, the adsorption capacity of multi-layered filters was significantly higher (16-100%) than for single-layer filters at the same overall weight. The effect of layer separation was also characterized using polypropylene separators and tested under constant flow rate operation. Separators provided more effective methylene blue adsorption by generating a well-distributed flow. Filtration performance was quantified with 0.5 μm silicon dioxide particles under constant pressure conditions; this is to mimic bacteria rejection. Filtration capability of SiO particles was reduced slightly (12%) with decreasing individual filter layer thickness regardless of the multi-layered structure. Filtering polyethylene glycol (PEG) molecules with two different molecular weights was performed; however, no rejection was recorded. The filter internal pore structure was visualized by 3D-X ray computed tomography and the void fraction was quantified. 400 gsm single layer presented areas of low fiber density forming pores, while the pore volume decreased for thinner filter layers.
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http://dx.doi.org/10.3389/fchem.2018.00417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143674PMC
September 2018

Bilateral medial malleolus stress fractures due to osteoarthritis of knee: A case report and review of literature.

Int J Surg Case Rep 2015 12;6C:266-8. Epub 2014 Dec 12.

Department of Trauma & Orthopaedics, Pinderfield General Hospital, Wakefield, West Yorkshire, UK.

Introduction: Medial malleolar stress fracture is a relatively uncommon injury but it can occur in athletes participating in running and jumping activities. Stress fractures of pelvis, proximal tibia and metatarsals are well documented in the elderly population but medial malleolus involvement in this subgroup has never been reported.

Presentation Of Case: We report a case of bilateral medial malleolus stress fractures secondary to bilateral knee osteoarthritis.

Discussion: Osteoporosis and mechanical malalignment have been postulated as the possible risk factors for stress fractures in the elderly population. The pathomechanics and management of the case are discussed here.

Conclusion: A high index of suspicion is required to identify such fractures. Identification and treatment of the predisposing factors are a very important part of treatment.
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http://dx.doi.org/10.1016/j.ijscr.2014.10.078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334956PMC
January 2015

Dengue eye disease.

Surv Ophthalmol 2015 Mar-Apr;60(2):106-14. Epub 2014 Aug 12.

Eagle Eye Centre, Singapore; National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore. Electronic address:

Dengue fever, a viral disease epidemic in some parts of the world, is of considerable international concern, with a growing incidence owing to developing urbanization, tourism, and trade. Ocular manifestations of dengue fever are uncommon, but of great significance. Proposed mechanisms include direct viral infection as well as immunologic phenomena. Common manifestations include subconjunctival, vitreous, and retinal hemorrhages; posterior uveitis; optic neuritis; and maculopathies such as foveolitis, hemorrhage, and edema. Main symptoms include blurring of vision, scotomata, metamorphopsia, and floaters. Diagnostic and monitoring investigations described included optical coherence tomography, fundus fluorescein and indocyanine green angiography, visual field analysis, and electrophysiologic tests. Management is based on clinical presentation and includes active surveillance as well as various anti-inflammatory and immunosuppressive therapies. There have been no prospective, randomized therapeutic trials, and it is unclear if the disease is self-limiting or if treatment is actually beneficial. Prognosis varies, ranging from full resolution to permanent vision loss despite intervention.
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http://dx.doi.org/10.1016/j.survophthal.2014.07.003DOI Listing
August 2015

A modified technique to extract fractured femoral stem in revision total hip arthroplasty: A report of two cases.

Int J Surg Case Rep 2014 16;5(7):361-4. Epub 2014 Apr 16.

Department of Trauma and Orthopaedics, Mid Yorkshire Hospitals NHS Trust, Pinderfields General Hospital, Wakefield, West Yorkshire WF1 4DG, United Kingdom.

Introduction: The removal of well-fixed broken femoral component and cement mantle can be extremely demanding, time consuming and potentially damaging to the host bone. Different methods have been described to extract broken femoral stem yet this remains one of the most challenging prospect to the revision hip surgeon.

Presentation Of Case: The authors present two cases underwent a modified sliding cortical window technique utilising a tungsten carbide drill, Charnley pin retractor and an orthopaedic mallet to aid extraction of a fractured cemented femoral stem in revision total hip arthroplasty.

Discussion: The modified technique offers a simple and controlled method in extracting a well fixed fractured cemented femoral stem. It has the advantage of retaining the cement mantle with subsequent good seal of the femoral cortical window secured with cable ready system. Furthermore, tungsten carbide drill bit and Charnley pin retractor are relatively readily available to aid the extraction of the broken stem. Finally, it yields the option of implanting a standard femoral stem and obviates the need for bypassing the cortical window with long revision femoral component.

Conclusion: Fractured femoral stem is a rare yet a complex and very demanding prospect to both patients and hip surgeons. The sliding cortical window technique utilising tungsten carbide drill and Charnley pin retractor is technically easy and most importantly; preserves host bone stock with cement-in-cement revision hip arthroplasty. We believe this technique can be added to the armamentarium of revision hip surgeon when faced with the challenge of extracting a fractured cemented femoral stem.
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http://dx.doi.org/10.1016/j.ijscr.2014.04.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4064393PMC
June 2014

Cataract surgery in patients with nanophthalmos.

Ophthalmology 2014 Feb 28;121(2):e11. Epub 2013 Nov 28.

Department of Ophthalmology, Wolverhampton Eye Infirmary, New Cross Hospital, Wolverhampton, United Kingdom.

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http://dx.doi.org/10.1016/j.ophtha.2013.10.012DOI Listing
February 2014

The long-term outcome of silastic implant arthroplasty of the first metatarsophalangeal joint: a retrospective analysis of one hundred and eight feet.

Int Orthop 2012 Sep 23;36(9):1865-9. Epub 2012 Jun 23.

SpR Trauma and Orthopaedics, 12 Netherwood Grove, Wigan WN3 6NF, UK.

Purpose: The short-term results of silastic implant of the first metatarsophalangeal joint (MTPJ) have been successful. However, reservations exist regarding long-term results. The aim of this study was to evaluate long-term outcome of silastic implant prosthesis in treatment of hallus rigidus.

Methods: This was a retrospective study, with 108 feet in 83 patients, operated upon between 1988 and 2003. Mean age at operation was 55 years (SD 8.1) with a follow-up period of 8.5 years. Outcome measures included the American Orthopaedic Foot and Ankle Scoring system(AOFAS), passive and active arc of motion. Patients' satisfaction was assessed using the visual analogue scale. All the patients had anteroposterior and oblique views and were assessed for loosening and osteolysis. Pedobarographic studies were performed using the Musgrave Footprint. Complications and revisions were recorded.

Results: The mean total AOFAS score was 77.5 (SD 13.4). Mean active and passive arc of motions were 36.8 degrees (SD 19.13) and 46.82 degrees (SD 17.19), respectively. Patient satisfaction showed mean VAS of 7.73 (SD 2.41). Prostheses were removed in three feet at three, five and seven years respectively because of persistent pain. Radiologically 25 feet (23 %) had osteolysis but were non progressive and didn't correlate with the functional outcome.

Conclusion: We can conclude that silastic implant arthroplasty is an effective procedure in hallux rigidus management with satisfactory functional outcome and high patient satisfaction.
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http://dx.doi.org/10.1007/s00264-012-1576-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427448PMC
September 2012

A technique for extracting a buried Kuntscher nail from the femur during total hip arthroplasty.

Hip Int 2010 Apr-Jun;20(2):292-5

Department of Orthopaedic Surgery, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.

We describe a novel technique that allows safe extraction of a buried Kuntscher nail during total hip arthroplasty in a patient with ipsilateral, symptomatic post-traumatic osteoarthritis of the hip. This method allows the surgeon to visualise the antegrade entry point of the nail allowing safe extraction of the device without compromising the result of the hip arthroplasty.
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http://dx.doi.org/10.1177/112070001002000227DOI Listing
October 2010

Preoperative footbaths reduce bacterial colonization of the foot.

Foot Ankle Int 2009 Sep;30(9):860-4

University Department of Orthopaedic Surgery, Manchester Royal Infirmary, United Kingdom.

Background: Previous studies have demonstrated higher infection rates following elective procedures on the foot and ankle compared with procedures involving other areas of the body. Previous studies also have documented the difficulty of eliminating bacteria from the forefoot prior to surgery. The purpose of the present study was to ascertain if preoperative chlorhexidine bathing decreased the number of bacteria on the forefoot.

Materials And Methods: From October 2005 to October 2006, a prospective study was undertaken to evaluate 44 consecutive patients undergoing planned, elective surgery of the foot and ankle. (mean age, 43.9 years; range, 17 to 85 years; 25 female, 19 male). Twenty-two patients were assigned to each group. They were randomly assigned to have preoperative footbath with chlorhexidine gluconate (Hibitane) (Group 1) 20 minutes before surgery or placebo (Group 2). Culture swabs were taken from all web spaces, nail folds, toe surfaces and proposed surgical incision sites before the preoperative bath, during the procedure and immediately after surgery.

Results: In Group 1, bacteria grew on the intraoperative culture in 60% and 0% of immediate postoperative cultures. In Group 2, 96% of intraoperative cultures and 16% of postoperative cultures. The difference in the intraoperative bacterial count was statistically significant (p = 0.002). The difference in postoperative bacterial counts was marginally significant (p = 0.055). No complications were recorded in either group.

Conclusion: These data indicate that chlorhexidine provides better reduction in skin flora than placebo. Based of these data, we recommend the use of a chlorhexidine footbath in addition to standard surgical preparatory agent before foot and ankle surgery.
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http://dx.doi.org/10.3113/FAI.2009.0860DOI Listing
September 2009

Comparison of Herbert and Acutrak screws in the treatment of scaphoid non-union and delayed union.

Acta Orthop Belg 2008 Dec;74(6):761-5

Department of Trauma and Orthopaedic Surgery, Royal Bolton Hospital, Minerva Road, Farnworth, Bolton, BL4 0JE, United Kingdom.

A retrospective analysis was performed on patients who had undergone surgery for delayed union or non-union of a scaphoid fracture. This was conducted to investigate if there was a difference in outcome between patients treated with the Acutrak screw or the Herbert screw. Twenty two cases were treated with a Herbert screw and 23 with an Acutrak screw. The patient demographics, aetiology of injury and fracture types were similar between the two groups. There was no significant difference in union rate or time to union for fractures treated with the Herbert screw or the Acutrak screw. There appears to be no difference in outcome for cases of scaphoid fracture delayed union and non-union treated with either the Herbert screw or the Acutrak screw.
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December 2008

Circumferential periosteal block in the reduction of distal radius fractures.

Ann R Coll Surg Engl 2005 Mar;87(2):141

Department of Orthopaedics, Royal Bolton Hospital, UK.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963874PMC
March 2005

The paediatric floating knee: a case report of ipsilateral epiphyseal injury to the distal femur and proximal tibia.

J Pediatr Orthop B 2004 Mar;13(2):110-3

Department of Trauma and Orthopaedic Surgery, St. James's University Hospital, Leeds, UK.

Although isolated epiphyseal trauma of the tibia and the femur have been described in the literature, the combination of these two injuries is extremely rare. We report on the management of a case of simultaneous ipsilateral epiphyseal injuries to the distal femur and proximal tibia, the paediatric floating knee.
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http://dx.doi.org/10.1097/00009957-200403000-00009DOI Listing
March 2004
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