Correction to: The WOMAC score can be reliably used to classify patient satisfaction after total knee arthroplasty.

Unfortunately, Fig. 1 in the original article contained incorrect information. Hereby, the correct figure is published and we apologise for the inconvenience.

The WOMAC score can be reliably used to classify patient satisfaction after total knee arthroplasty.

PURPOSE: The primary aim of this study was to define a classification in the WOMAC score after total knee arthroplasty (TKA) according to patient satisfaction. The secondary aims were to describe patient demographics for each level of satisfaction. METHODS: A retrospective cohort consisting of 2589 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and short form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed at 1 year with four responses: very satisfied, satisfied, dissatisfied or very dissatisfied. Receiver operating characteristic (ROC) curves were used to identify values in the components and total WOMAC scores that were predictive of each level of satisfaction, which were used to define the categories of excellent, good, fair and poor. RESULTS: At 1 year, there were 1740 (67.5%) very satisfied, 572 (22.2%) satisfied, 190 (7.4%) dissatisfied and 76 (2.9%) very dissatisfied patients. ROC curve analysis identified excellent, good, fair and poor categories for the pain (> 78, 59-78, 44-58, < 44), function (> 72, 54-72, 41-53, < 41), stiffness (> 69, 56-69, 43-55, < 43) and total (> 75, 56-75, 43-55, < 43) WOMAC scores, respectively. Patients with lung disease, diabetes, gastric ulcer, kidney disease, liver disease, depression, back pain, with worse pre-operative functional scores (WOMAC and SF-12) and those with less of an improvement in the scores, had a significantly lower level of satisfaction. CONCLUSION: This study has defined a post-operative classification of excellent, good, fair and poor for the components and total WOMAC scores after TKA. The predictors of level of satisfaction should be recognised in clinical practice and patients at risk of a lower level of satisfaction should be made aware in the pre-operative consent process. LEVEL OF EVIDENCE: III.

Changes in surface topography at the TKA backside articulation following in vivo service: a retrieval analysis.

PURPOSE: With the advent of modular total knee arthroplasty (TKA) systems, backside wear at the articulation between the ultra-high-molecular-weight-polyethylene (UHMWPE) component undersurface and the tibial baseplate has received increasing attention as a source of clinically significant polyethylene wear debris. The aim of this study was to investigate the reciprocating interface at the TKA undersurface articulation using profilometry after in vivo service. Our null hypothesis was that there would be no discernible pattern or relationship between the metal tibial baseplate and UHMWPE surface profile. METHODS: A nanoscale analysis of thirty retrieved fixed-bearing TKA explants was performed. Surface roughness (Sa) and skewness (Ssk) were measured on both the UHMWPE component undersurface and the tibial baseplate of explants using a non-contacting profilometer (1 nm resolution). Four pristine unimplanted components of two different designs (Stryker Kinemax and DePuy PFC) were examined for control purposes. RESULTS: Mean explant baseplate surface roughness was 1.24 µm (0.04-3.01 µm). Mean explant UHMWPE undersurface roughness was 1.16 µm (0.23-2.44 µm). Each explant had an individual roughness pattern with unique baseplate and undersurface UHMWPE surface roughness that was different from, but closely related to, surface topography observed in control implants of the same manufacturer and design. Following in vivo service, UHMWPE undersurface showed changes towards a negative skewness, demonstrating that wear is occurring at the backside interface. CONCLUSION: In vivo loading of the TKA prosthesis leads to measurable changes in surface profile at the backside articulation, which appear to be dependent on several factors including implant design and in vivo duration. These findings are consistent with wear occurring at this surface. Findings of this study would support the use of a polished tibial tray over an unpolished design in total knee arthroplasty with the goal of reducing PE wear by means of providing a smoother backside countersurface for the UHMWPE component.

Topographical analysis of the femoral components of ex vivo total knee replacements.

With greater numbers of primary knee replacements now performed in younger patients there is a demand for improved performance. Surface roughness of the femoral component has been proposed as a causative mechanism for premature prosthesis failure. Nineteen retrieved total knee replacements were analysed using a non-contacting profilometer to measure the femoral component surface roughness. The Hood technique was used to analyse the wear and surface damage of the matching ultra-high molecular weight polyethylene (UHMWPE) tibial components. All femoral components were shown to be up to 11× rougher after their time in vivo while 95 % showed a change in skewness, further indicating wear. This increase in roughness occurred relatively soon after implantation (within 1 year) and remained unchanged thereafter. Mostly, this roughness was more apparent on the lateral condyle than the medial. This increased femoral surface roughness likely led to damage of the UHMWPE tibial component and increased Hood scores.

Patterns of changes in femoral bone mineral density up to five years after hip resurfacing.

This is a prospective study of 26 patients (29 hips) on the patterns of change in the Bone Mineral Density (BMD) in various zones of the femoral neck and proximal femur five years after hip resurfacing. We have found that BMD continues to positively change up to five years after hip resurfacing. This was observed primarily in the trochanteric and superior neck regions. In both these regions BMD had decreased by up to 10% at six-weeks and three-months after surgery and then had recovered to preoperative level by one year. A regression analysis to assess the influence of age, gender, BMI, preoperative BMD, component size and orientation revealed that the best predictor of change in BMD at five years in the trochanteric area was acetabular component inclination.

Bacterial amplification and in-place carpet drying: implications for category 1 water intrusion restoration.

The study described in this article investigated whether in-place carpet drying processes resulted in bacterial amplification following water intrusion from a clean water source (category 1) in a residential indoor environment. Bacterial amplification was examined after wetting a 10-year-old carpet and pad that had no history of water intrusion. Three test areas were extracted and dried using industry-recommended procedures for in-place drying and compared to a control area that was not extracted or dried. Results from carpet, pad, and subsurface dust demonstrated that bacterial amplification occurred in all test areas. CFUs of bacteria per gram of carpet surface dust and subsurface dust prior to water intrusion were lower than levels in subsurface dust after in-place drying. The authors' study contributes to information regarding the restoration of water-based carpet damage by professional water damage restoration companies, building maintenance personnel, and housekeeping managers. Results suggest that the appropriate response time for carpet pad salvage is considerably shorter than the current industry recommendation of 72 hours.

Seromadesis following total hip resurfacing by aspiration and injection of doxycycline.

Here, we present an interesting case of seroma following hip resurfacing arthroplasty in a 69-year-old man. During the postoperative recovery, the patient made rapid progress and returned to intense activity within the 6-week period. He subsequently developed further right hip pain and swelling. On further examination and on ultrasound scan, a lateral thigh collection was noted. All inflammatory markers were within normal parameters; clinically, there was no evidence of active infection. On initial aspiration and washout, there was a large sterile haemoserous collection. The patient subsequently underwent further aspiration due to persistent collection. After this a revision procedure was performed in two stages with excision of the seroma cavity superficial to fascia lata. Methicillin-sensitive Staphylococcus aureus was grown on extended cultures which was treated successfully with antibiotics. After the second stage revision to total hip replacement, this cavity then recollected. A further trial of aspiration with injection of 200 mg doxycycline, a known sclerosing agent, was performed. The seroma resolved.

Panzea: a database and resource for molecular and functional diversity in the maize genome.

Serving as a community resource, Panzea (http://www.panzea.org) is the bioinformatics arm of the Molecular and Functional Diversity in the Maize Genome project. Maize, a classical model for genetic studies, is an important crop species and also the most diverse crop species known. On average, two randomly chosen maize lines have one single-nucleotide polymorphism every approximately 100 bp; this divergence is roughly equivalent to the differences between humans and chimpanzees. This exceptional genotypic diversity underlies the phenotypic diversity maize needs to be cultivated in a wide range of environments. The Molecular and Functional Diversity in the Maize Genome project aims to understand how selection has shaped molecular diversity in maize and then relate molecular diversity to functional phenotypic variation. The project will screen 4000 loci for the signature of selection and create a wide range of maize and maize-teosinte mapping populations. These populations will be genotyped and phenotyped, permitting high-power and high-resolution dissection of the traits and relating the molecular diversity to functional variation. Panzea provides access to the genotype, phenotype and polymorphism data produced by the project through user-friendly web-based database searches and data retrieval/visualization tools, as well as a wide variety of information and services related to maize diversity.

The effect of artificial selection on phenotypic plasticity in maize.

Remarkable productivity has been achieved in crop species through artificial selection and adaptation to modern agronomic practices. Whether intensive selection has changed the ability of improved cultivars to maintain high productivity across variable environments is unknown. Understanding the genetic control of phenotypic plasticity and genotype by environment (G × E) interaction will enhance crop performance predictions across diverse environments. Here we use data generated from the Genomes to Fields (G2F) Maize G × E project to assess the effect of selection on G × E variation and characterize polymorphisms associated with plasticity. Genomic regions putatively selected during modern temperate maize breeding explain less variability for yield G × E than unselected regions, indicating that improvement by breeding may have reduced G × E of modern temperate cultivars. Trends in genomic position of variants associated with stability reveal fewer genic associations and enrichment of variants 0-5000 base pairs upstream of genes, hypothetically due to control of plasticity by short-range regulatory elements.

Difference in the acetabular cup orientation in standing and supine radiographs.

Acetabular orientation changes with that of the pelvis during lying and standing. This study was designed to measure these changes. We assessed 17 BHR replacements using EBRA software. The mean acetabular anteversion was more (p = 0.02) on erect than supine radiographs. Linear regression analysis showed that anteversion and inclination increased in some while decreased in others, and Bland and Altman analysis showed wide limits of agreement. The changes in acetabular orientation are thus subject to significant variations between the patients. We suggest studying the factors affecting acetabular orientation in standing to help reduce joint reaction forces and improve outcomes.

The effect of delay to surgery on morbidity, mortality and length of stay following periprosthetic fracture around the hip.

With the increasing prevalence of total hip arthroplasty and the increasing longevity of patients with implants in situ, periprosthetic fractures of the proximal femur are seen with greater frequency. They represent a challenging surgical problem, requiring combined arthroplasty and trauma skills in a potentially compromised surgical bed. We present data from the 82 consecutive patients with periprosthetic fractures around the hip presenting to two NHS Foundation Trusts in the period January 2009 to February 2014. Inpatient mortality across all sites was 11.0%. This increased to 17.1% at 1 year. There was no association between delay to surgery and either inpatient or 1 year mortality. Mean delay to surgery was 4.1 days in those without inpatient mortality, 5.2 days in those with (p=0.3075). Mean delay to surgery was 4.5 days in those with 1 year mortality, 4.16 days in those without (p=0.6203). The number of post-operative complications was not significantly positively correlated with increasing delay to surgery (Pearson correlation coefficient -0.04437). It would appear that a delay to order necessary equipment and obtain relevant surgical expertise for the treatment of these complex fractures is safe and not associated with increased mortality or post-operative complications.

Maize HapMap2 identifies extant variation from a genome in flux.

Whereas breeders have exploited diversity in maize for yield improvements, there has been limited progress in using beneficial alleles in undomesticated varieties. Characterizing standing variation in this complex genome has been challenging, with only a small fraction of it described to date. Using a population genetics scoring model, we identified 55 million SNPs in 103 lines across pre-domestication and domesticated Zea mays varieties, including a representative from the sister genus Tripsacum. We find that structural variations are pervasive in the Z. mays genome and are enriched at loci associated with important traits. By investigating the drivers of genome size variation, we find that the larger Tripsacum genome can be explained by transposable element abundance rather than an allopolyploid origin. In contrast, intraspecies genome size variation seems to be controlled by chromosomal knob content. There is tremendous overlap in key gene content in maize and Tripsacum, suggesting that adaptations from Tripsacum (for example, perennialism and frost and drought tolerance) can likely be integrated into maize.

Safety of helicopter aeromedical transport in Australia: a retrospective study.

OBJECTIVES: To determine the accident rate for Australian helicopter emergency medical services (HEMS) per 100,000 flying hours and to determine the patient mortality risk per mission from a HEMS accident. METHOD: Retrospective observational study of Australian HEMS flying hours and accidents from 1992-2002. RESULTS: The calculated accident rate for Australian HEMS is 4.38 per 100,000 flying hours. One patient died as a direct result of helicopter accident in 50,164 missions. Overall, one accident occurred every 16,721 missions. CONCLUSIONS: The overall Australian HEMS accident rate is similar to that reported from other countries, with all accidents occurring in Queensland community HEMS. Helicopters flown at night under Visual Flight Rules (VFR) appear to represent a high-risk subgroup. HEMS flights do not appear to present significant mortality risk to patients being transported.