Large multiplanar changes to native alignment have no apparent impact on clinical outcomes following total knee arthroplasty.

PURPOSE: This study sought to examine if achieved postoperative alignment when compared to the native anatomy would lead to a difference in Patient Reported Outcome Measures (PROMs), and whether the achieved alignment could be broadly categorised by an accepted alignment strategy. METHODS: A retrospective cohort study of prospectively collected data on patients undergoing single primary or bilateral simultaneous total knee arthroplasty (TKA) was carried out. CT scans were used to determine the mean change ("delta values") between the pre and postoperative; hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle and femoral implant rotation. Femoral implant flexion and tibial implant slope were measured postoperatively. The primary outcome was the relationship of the variables to the change in KOOS pain subscale after one year. The secondary outcome was the number of knees which could be categorised postoperatively to an alignment strategy, and the mean PROMs in each cohort. RESULTS: A total of 296 knees in 261 patients were available for analysis. With regards to the primary outcome, the delta values for each variable did not demonstrate any association with the change in knee injury and osteoarthritis outcome score (KOOS) pain score. Approximately 46% of knees could not be categorised to an alignment strategy based on postoperatively measured alignment, with no significant difference between each cohort with regards to the change in KOOS Pain score. CONCLUSION: Achieved alignment does not consistently match accepted alignment strategies, and appears to confer no benefit to clinical outcomes when the native anatomy is most closely approximated, nor results in poorer outcomes in outliers. This study highlights the importance of routine three dimensional pre and postoperative imaging in clinical practice and for the valid analysis of outcomes in studies on alignment. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Ancient marine sediment DNA reveals diatom transition in Antarctica.

Antarctica is one of the most vulnerable regions to climate change on Earth and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency. Sedimentary ancient DNA (sedaDNA) analysis can provide such insights into past ecosystem-wide changes. Here we present authenticated (through extensive contamination control and sedaDNA damage analysis) metagenomic marine eukaryote sedaDNA from the Scotia Sea region acquired during IODP Expedition 382. We also provide a marine eukaryote sedaDNA record of ~1 Mio. years and diatom and chlorophyte sedaDNA dating back to ~540 ka (using taxonomic marker genes SSU, LSU, psbO). We find evidence of warm phases being associated with high relative diatom abundance, and a marked transition from diatoms comprising <10% of all eukaryotes prior to ~14.5 ka, to ~50% after this time, i.e., following Meltwater Pulse 1A, alongside a composition change from sea-ice to open-ocean species. Our study demonstrates that sedaDNA tools can be expanded to hundreds of thousands of years, opening the pathway to the study of ecosystem-wide marine shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles.

Episodes of Early Pleistocene West Antarctic Ice Sheet Retreat Recorded by Iceberg Alley Sediments.

Ice loss in the Southern Hemisphere has been greatest over the past 30 years in West Antarctica. The high sensitivity of this region to climate change has motivated geologists to examine marine sedimentary records for evidence of past episodes of West Antarctic Ice Sheet (WAIS) instability. Sediments accumulating in the Scotia Sea are useful to examine for this purpose because they receive iceberg-rafted debris (IBRD) sourced from the Pacific- and Atlantic-facing sectors of West Antarctica. Here we report on the sedimentology and provenance of the oldest of three cm-scale coarse-grained layers recovered from this sea at International Ocean Discovery Program Site U1538. These layers are preserved in opal-rich sediments deposited ∼1.2 Ma during a relatively warm regional climate. Our microCT-based analysis of the layer's in-situ fabric confirms its ice-rafted origin. We further infer that it is the product of an intense but short-lived episode of IBRD deposition. Based on the petrography of its sand fraction and the Phanerozoic 40Ar/39Ar ages of hornblende and mica it contains, we conclude that the IBRD it contains was likely sourced from the Weddell Sea and/or Amundsen Sea embayment(s) of West Antarctica. We attribute the high concentrations of IBRD in these layers to "dirty" icebergs calved from the WAIS following its retreat inland from its modern grounding line. These layers also sit at the top of a ∼366-m thick Pliocene and early Pleistocene sequence that is much more dropstone-rich than its overlying sediments. We speculate this fact may reflect that WAIS mass-balance was highly dynamic during the ∼41-kyr (inter)glacial world.

Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years.

The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.

Outcomes of older COVID-19 patients in Acute Care at Home, Southern HSC Trust, Northern Ireland, from March - June 2020.

INTRODUCTION: The older population has been most affected by COVID-19, with mortality rates of around 27%. The Acute Care at Home (ACAH) team aims to improve outcomes in the older population by preventing hospital admission or facilitating early discharge, allowing patients to be treated in their own environment. During the COVID-19 pandemic, the ACAH team administered oxygen therapy, antibiotics, anticipatory medications and other vital interventions to combat the ill effects of COVID-19. METHOD: An observational approach has been used in this study. Patients were included if they were admitted to ACAH during March-June 2020 for treatment of COVID-19. Biochemistry, oxygen saturations and co-morbidities are among the studied parameters. Lymphocyte count and serum magnesium were compared with a non-COVID-19 cohort. Trends within parameters and associated mortality were analysed and tabulated. RESULTS: 70% of admissions were lymphopenic, whilst 54% were hypoxic. There was a 28-day mortality rate of 35%, with an 18% increase in mortality rate when comparing residence in long-term care facilities (LTCF) to personal residence. All patients had existing co-morbidities. CONCLUSION: The data indicates that hypoxaemia, hyperferritinaemia and hypermagnesaemia are associated with early mortality in the older population infected with COVID-19. National Early Warning Score and frailty score are predictive of mortality in this cohort, with higher scores correlating to worse outcomes. Those living in LTCF are at an increased risk of mortality. However, ACAH mortality rates are comparable to those admitted to hospital, validating the concept of ACAH. The highlighted trends can be used to improve outcomes in future admissions.

Are patient-reported outcomes the same following second-side surgery in primary hip and knee arthroplasty?

AIMS: Up to one in five patients undergoing primary total hip (THA) and knee arthroplasty (TKA) require contralateral surgery. This is frequently performed as a staged procedure. This study aimed to determine if outcomes, as determined by the Oxford Hip Score (OHS) and Knee Score (OKS) differed following second-side surgery. METHODS: Over a five-year period all patients who underwent staged bilateral primary THA or TKA utilizing the same type of implants were studied. Eligible patients had both preoperative and one year Oxford scores and had their second procedure completed within a mean (2 SDs) of the primary surgery. Patient demographics, radiographs, and OHS and OKS were analyzed. RESULTS: A total of 236 patients met the inclusion criteria, of which 122 were THAs and 114 TKAs. The mean age was 66.5 years (SD 9.4), with a 2:1 female:male ratio. THAs showed similar significant improvements in outcomes following first- and second-side surgery, regardless of sex. In contrast for TKAs, although male patients demonstrated the same pattern as the THAs, female TKAs displayed significantly less improvement in both OKS and its pain component following second-side surgery. CONCLUSION: Female patients undergoing second-side TKA showed less improvement in Oxford and pain scores compared to the first-side. This difference in outcome following second-side surgery did not apply to male patients undergoing TKA, or to either sex undergoing THA. Cite this article: Bone Jt Open 2021;2(4):243-254.

Are There Gender-Specific Errors in Restoration of Hip Biomechanics That Affect Outcome Following Total Hip Arthroplasty?

BACKGROUND: There are morphologic differences between males and females, which are currently underappreciated during total hip arthroplasty. We sought to assess whether these differences affected surgical process and subsequent outcome. METHODS: A total of 123 patients (75 females, 48 males) had preoperative and 1-year Oxford Hip Score (OHS) and pain scores recorded. Acetabular height and offset, femoral height and offset, and acetabular floor depth were measured on preoperative and postoperative X-rays and then compared to their normal opposite hip. Discrepancies between the replaced and normal hip X-ray measurements were then correlated with changes (the delta gain) in preoperative and 1-year postoperative OHS and pain scores. RESULTS: Postoperatively, females had significantly greater femoral height discrepancy (P = .023) which meant they were lengthened. This led to a reduced delta gain in OHS and pain score at 1 year. Males lost more acetabular offset than females (P = .002), leading to a medialized acetabular center and subsequently reduced delta gain in pain score at 1 year (P = .017). CONCLUSION: Females have a smaller femur leading to a bias toward a conservative (higher) neck cut compared with males and potential for femoral lengthening. Males have a greater acetabular floor depth compared with females and thus reaming to the true floor results in greater loss of acetabular offset. In this series, both scenarios led to reduced improvement in OHS and/or pain scores at 1 year.

Independent restoration of femoral and acetabular height reduces limb length discrepancy and improves reported outcome following total hip arthroplasty.

BACKGROUND: Restoration of native hip biomechanics is viewed as a key intra-operative goal in total hip arthroplasty (THA). The transverse acetabular ligament (TAL) can aid in the restoration of acetabular height and offset, and a calliper can be utilised to restore femoral height and offset. This study aimed to determine how these techniques affected the incidence of patient perception of limb length discrepancy (LLD), and if restoration of native biomechanics correlated with improved patient outcomes. METHODS: 123 patients were questioned regarding perception of LLD at 6 weeks and 1 year following THA. Oxford hip score (OHS) and pain scores were recorded. Radiographs were analysed by a blinded clinician who measured three variables; Global hip height (surrogate for limb length), global offset and the combination of both. These measurements were then compared to the unaffected contralateral hip. Data were analysed based on hips that were restored to within ≤±10 mm of native values, and those >±10 mm. Spearman's rank test was used to assess correlation with outcome. RESULTS: 8 (6.5%) patients perceived a LLD at 6 weeks, reducing to 3 (2.4%) at 1 year-lower than generally reported. Those patients not restored within ±10 mm of native global height had increased pain at 1 year (r = 0.558, p = 0.047). Those not restored within ±10 mm native global offset had a poorer OHS at 1 year (r = -0.586, p = 0.035) and those patients with combined height and offset discrepancy >±10 mm had both a worse OHS (r = -0.581, p = 0.037) and increased pain (r = 0.783, p = 0.002). CONCLUSION: Patient perception of LLD is complex and relates poorly to radiographic measurement, however, patients not restored to within 10 mm of native hip height and offset have demonstrated poorer outcomes.

Abundance and richness of key Antarctic seafloor fauna correlates with modelled food availability.

Most seafloor communities at depths below the photosynthesis zone rely on food that sinks through the water column. However, the nature and strength of this pelagic-benthic coupling and its influence on the structure and diversity of seafloor communities is unclear, especially around Antarctica where ecological data are sparse. Here we show that the strength of pelagic-benthic coupling along the East Antarctic shelf depends on both physical processes and the types of benthic organisms considered. In an approach based on modelling food availability, we combine remotely sensed sea-surface chlorophyll-a, a regional ocean model and diatom abundances from sediment grabs with particle tracking and show that fluctuating seabed currents are crucial in the redistribution of surface productivity at the seafloor. The estimated availability of suspended food near the seafloor correlates strongly with the abundance of benthic suspension feeders, while the deposition of food particles correlates with decreasing suspension feeder richness and more abundant deposit feeders. The modelling framework, which can be modified for other regions, has broad applications in conservation and management, as it enables spatial predictions of key components of seafloor biodiversity over vast regions around Antarctica.

New data towards the development of a comprehensive taphonomic framework for the Late Jurassic Cleveland-Lloyd Dinosaur Quarry, Central Utah.

The Cleveland-Lloyd Dinosaur Quarry (CLDQ) is the densest deposit of Jurassic theropod dinosaurs discovered to date. Unlike typical Jurassic bone deposits, it is dominated by the presence of Allosaurus fragilis. Since excavation began in the 1920s, numerous hypotheses have been put forward to explain the taphonomy of CLDQ, including a predator trap, a drought assemblage, and a poison spring. In an effort to reconcile the various interpretations of the quarry and reach a consensus on the depositional history of CLDQ, new data is required to develop a robust taphonomic framework congruent with all available data. Here we present two new data sets that aid in the development of such a robust taphonomic framework for CLDQ. First, x-ray fluorescence of CLDQ sediments indicate elevated barite and sulfide minerals relative to other sediments from the Morrison Formation in the region, suggesting an ephemeral environment dominated by periods of hypereutrophic conditions during bone accumulation. Second, the degree of abrasion and hydraulic equivalency of small bone fragments dispersed throughout the matrix were analyzed from CLDQ. Results of these analyses suggest that bone fragments are autochthonous or parautochthonous and are derived from bones deposited in the assemblage rather than transported. The variability in abrasion exhibited by the fragments is most parsimoniously explained by local periodic re-working and re-deposition during seasonal fluctuations throughout the duration of the quarry assemblage. Collectively, these data support previous interpretations that the CLDQ represents an attritional assemblage in a poorly-drained overbank deposit where vertebrate remains were introduced post-mortem to an ephemeral pond during flood conditions. Furthermore, while the elevated heavy metals detected at the Cleveland-Lloyd Dinosaur Quarry are not likely the primary driver for the accumulation of carcasses, they are likely the result of multiple sources; some metals may be derived from post-depositional and diagenetic processes, and others are potentially produced from an abundance of decomposing vertebrate carcasses. These new data help to support the inferred depositional environment of the quarry as an ephemeral pond, and represent a significant step in understanding the taphonomy of the bonebed and Late Jurassic paleoecology in this region.

Improving efficiency of a regional stand alone bone bank.

The introduction of a stand-alone Bone Bank in our Regional Orthopaedic Hospital has improved the availability of femoral head allograft. Benninger et al. (Bone Joint J 96-B:1307-1311, 2014), demonstrated their institutions bank to be cost effective despite a 30 % discard rate for harvested allograft. We sought to audit our own discard rates and subsequent cost-effectiveness of our bone bank. Donor recruitment. Before approaching a potential donor, our establishment's nurse specialists review their clinical notes and biochemical laboratory results, available on a regional Electronic Care Records. They view femoral head architecture on radiographs against set criteria, Patient Archive and Communication system (SECTRA, Sweden). In total 1383 femoral heads were harvested, 247 were discarded giving an overall rate of 17.9 %. The most common reasons for discard of harvested graft was a positive microbiology/bacteriology result, n = 96 (38.9 %). After a rise in discard rates in 2007, we have steadily reduced our discard rates since 2006/2007 (28.2 %), 2008/2009 (17 %), 2010/2011 (14.8 %), and finally to 10.3 % in 2012/2013. In the current financial year, our cost to harvest, test, store and release a femoral head is £ 610. With a structured donor recruitment process and unique pre-operative radiographic analysis we have successfully reduced our discard rates bi-annually making our bone bank increasingly cost-effective.

Improving handover of acute orthopaedic admissions.

Handover is a crucial part of patient care and is a well recognized cause of patient harm if not performed well. The introduction of full shift working for doctors has placed even more emphasis on this area of patient care. We identified handover of orthopaedic admissions in our unit was substandard. A prospective audit over a one week period including the weekend was undertaken. The Royal College of Surgeons of England guidance on handovers was used as minimum criteria and we also included criteria essential for handover of orthopaedic patients. This initial audit revealed a poor standard of handover. 21 patients were included and in particular patient location (57%), responsible consultant (14%), and pending investigations (29%) were poorly performed. In addition two patient safety incidents were noted, including one admission that was not handed over. To improve the handover we created a trauma specific handover proforma. We then conducted a re-audit again over a one week period including the weekend with the proforma in use. There was a notable improvement, 17 patients were included and only 3 criteria fell below 80%. We presented our findings at the local audit meeting where the results were discussed with all members of the trauma team. We suggested that an electronic proforma, accessible from multiple computers within the hospital may improve handover further. This was created in conjunction with the IT department. Once again we reaudited handover over a one week period including the weekend with the electronic proforma in use. 23 patients were included and a further improvement was noted; only one criterion fell below 95%. In conclusion handover of acute fracture admissions within the unit has undoubtedly improved. The electronic proforma tool was a simple, cost effective, and accurate method of improving handover.