Timing of Readmissions After Elective Total Hip and Knee Arthroplasty: Does a 30-Day All-Cause Rate Capture Surgically Relevant Readmissions?

BACKGROUND: The 30-day all-cause readmission rate is a widely used metric of hospital performance. However, there is lack of clarity as to whether 30 days is an appropriate time frame following surgical procedures. Our aim is to determine whether a 90-day time window is superior to a 30-day time window in capturing surgically relevant readmissions after total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: We analyzed readmissions following all primary THAs and TKAs recorded in the English National Health Service Hospital Episode Statistics database from 2008 to 2018. We compared temporal patterns of 30- and 90-day readmission rates for the following types of readmission: all-cause, surgical, return to theater, and those related to specific surgical complications. RESULTS: A total of 1.47 million procedures were recorded. After THA and TKA, over three-quarters of 90-day surgical readmissions took place within the first 30 days (78.5% and 75.7%, respectively). All-cause and surgical readmissions both peaked at day 4 and followed a similar temporal course thereafter. The ratio of surgical to medical readmissions was greater for THA than for TKA, with THA dislocation both being one of the most common surgical complications and clustering early after discharge, with 73.5% of 90-day dislocations occurring within the first 30 days. CONCLUSION: The 30-day all-cause readmission rate is a good reflection of surgically relevant readmissions that take place in the first 90 days after THA and TKA.

Venous thromboembolism rates after hip and knee arthroplasty and hip fractures.

BACKGROUND: The ideal thromboprophylaxis regime following lower limb arthroplasty and proximal femur fractures remains controversial. Guidelines disagree on the type of chemical prophylaxis, its dose or duration. This article describes a method of monitoring venous thromboembolism (VTE) rates following Total Hip (THA), Total Knee Arthroplasty (TKA) and surgery for hip fractures (NOF#). METHODS: Over 3 years, all patients investigated for VTE were analysed using Picture Archiving Communications System (PACS). All positive scans were then cross-referenced using PACS and local registry data to see if they had undergone THA, TKA or NOF# in the preceding 90 days. Mortality data were obtained from the national administrative database, Hospital Episode Statistics. RESULTS: Five thousand seven hundred eighty-eight patients underwent investigation for VTE and there were 29 diagnoses of PE and 24 of DVT. There was a 0.77% rate of symptomatic DVT after THA, 0.05% after TKA and 0.55% after NOF #. The rate of confirmed symptomatic PE for THA was 0.46, 0.27% for TKA and 0.96% for NOF #. Mortality at one-year post-THA was 0.6, 0.6% for TKA and 25.9% after NOF#. All patients contacted either remained within the catchment area for the minimum 90 postoperative days or died within the catchment area. CONCLUSIONS: The 90 day post-operative prevalence of symptomatic VTE of 1.2, 0.3 and 1.5% in THA, TKA and NOF # respectively are similar to other studies using symptomatic and imaging positive VTE as their endpoint. The study uses a method of collecting data which can be utilised in centres where PACS is available.

Predictors of 30-Day Readmission After Total Knee Arthroplasty: Analysis of 566,323 Procedures in the United Kingdom.

BACKGROUND: All-cause 30-day readmission after total knee arthroplasty (TKA) is currently used as a measure of hospital performance in the United States and elsewhere. Readmissions from surgical causes may more accurately reflect preventability and costs. However, little is known about whether predictors of each type of readmission differ. METHODS: All primary TKAs recorded in England's National Health Service administrative database from 2006 to 2015 were included. Multilevel logistic regression analysis was used to describe the effects of patient-related factors on 30-day readmission risk using 3 different readmission metrics: all-cause, surgical (defined using International Classification of Disease-10 primary admission diagnoses), and those resulting in return to theater (RTT). RESULTS: In total, 566,323 procedures were recorded. The comorbidity with the highest odds ratio (OR) for all types of readmission was psychoses (RTT OR 2.52, P < .001). Obesity was a strong independent predictor of RTT (OR 1.36, P < .001) and had the highest population attributable fraction of any comorbidity (4.7%). Unicompartmental arthroplasty was associated with a significantly lower risk of all types of readmission when compared with TKA, with the effect being most pronounced for surgical readmission (OR 0.66, P < .001). RTT in the index episode increased the risk of RTT readmission (OR 2.80, P < .001), as did any emergency admission to hospital in the preceding 12 months (for >2 emergency admissions, all-cause OR 2.38, P < .001). Length of stay either more than or less than 2 days was associated with an increased risk of all-cause and surgical readmission but not RTT readmission. CONCLUSION: Patient-related predictors of surgical and RTT readmission following TKA differ from those for all-cause readmission, but only the latter metric is in widespread use.

Comparison of 3 Types of Readmission Rates for Measuring Hospital and Surgeon Performance After Primary Total Hip and Knee Arthroplasty.

BACKGROUND: All-cause 30-day hospital readmission is in widespread use for monitoring and incentivizing hospital performance for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, little is known on the extent to which all-cause readmission is influenced by hospital or surgeon performance and whether alternative measures may be more valid. METHODS: This is an observational study using multilevel modeling on English administrative data to determine the interhospital and intersurgeon variation for 3 readmission metrics: all-cause, surgical, and return-to-theater. Power calculations estimated the likelihood of identifying whether the readmission rate for a surgeon or hospital differed from the national average by a factor of 1.25, 1.5, 2, or 3 times, for both average and high-volume providers. RESULTS: 259,980 THAs and 311,033 TKAs were analyzed. Variations by both surgeons and hospitals were smaller for the all-cause measure than for the surgical or return-to-theater metrics, although statistical power to detect differences was higher. Statistical power to detect surgeon-level rates of 1.25 or 1.5 times the average was consistently low. However, at the hospital level, the surgical readmission measure showed more variation by hospital while maintaining excellent power to detect differences in rates between hospitals performing the average number of THA or TKA cases per year in England. In practice, more outliers than expected from purely random variation were found for all-cause and surgical readmissions, especially at hospital level. CONCLUSION: The 30-day surgical readmission rate should be considered as an adjunctive measure to 30-day all-cause readmission rate when assessing hospital performance.

Osteochondral fracture of the lateral femoral condyle involving the entire weight bearing articular surface fixed with biodegradable screws.

Osteochondral fracture of lateral femoral condyle can result from support and other twisting injuries of the knee. Arthroscopy is a better diagnostic and therapeutic tool as standard radiographs can mislead regarding the size and location of the fragment. If fragment is large and displaced, arthrotomy may become necessary. We present a case of large osteochondral fracture of lateral femoral condyle involving the entire articular surface in a 12 year old male. This was treated with open reduction and internal fixation using biodegradable screws. MRI at six weeks after surgery showed satisfactory results. After the surgery full weight bearing was allowed at three months.

Testing Densities and Refractive Indices of Extraterrestrial Ice Components Using Molecular Structures - Organic Compounds and Molar Refractions.

The use of infrared spectra to determine molecular abundances of icy astronomical objects and to study their chemistry requires laboratory measurements of reference spectra and related quantities, such as the index of refraction (n) and density (ρ) of candidate ices. Here we present new n and ρ measurements on ices involving over thirty C-, H-, and O-containing compounds, both acyclic and cyclic, representing seven chemical families. We examine the results in a way that is rare in the astrochemical literature, namely one in which data from an ice formed from molecules of a particular chemical family are compared to measurements on another member of the same family, such as of a homologous series or a pair of isomers. Apart from the intrinsic usefulness of the n and ρ data, a structure-based comparison can help establish trends and identify possibly spurious results. As liquid-phase data sometimes are used in low-temperature astrochemical work in the absence of solid-phase measurements, we compare our new ice results to those for the corresponding room-temperature liquids. We emphasize the use of our n and ρ data to compute the molar refraction (R M ) for each of our ices, and how the resulting R M values compare to those expected from molecular structures. The use of calculated RM values and measured n values to calculate ice densities, in the absence of direct measurements, also is addressed.

Risk factors for early revision after total hip and knee arthroplasty: National observational study from a surgeon and population perspective.

AIMS: To identify predictors of early revision (within 3 years of the index operation) for hip and knee replacement (HR, KR) from both surgeon and population perspectives. PATIENTS AND METHODS: Hierarchical logistic regression on national administrative data for England for index procedures between April 2009 and March 2014. RESULTS: There were 315,273 index HR procedures and 374,530 index KR procedures for analysis. Three-year revision rates were 2.1% for HR and 2.2% for KR. The highest odds ratios for HR were for 3+ previous emergency admissions, drug abuse, Parkinson's disease, resurfacing and ages under 60; for KR these were patellofemoral or partial joint replacement, 3+ previous emergency admissions, paralysis and ages under 60. Smaller effects were found for other comorbidities such as obesity (HR) and diabetes (KR). From a population perspective, the only population attributable fractions over 5% were for male gender, uncemented total hip replacements and partial knee or patellofemoral replacements. CONCLUSIONS: Meeting the rising demand for revision surgery is a challenge for healthcare leaders and policymakers. Our findings suggest optimising patients pre-operatively and improving patient selection for primary arthroplasty may reduce the burden of early revision of arthroplasty. Our study gives useful information on the additional risks of various comorbidities and procedures, which enables a more informed consent process. CLINICAL RELEVANCE: Surgeons should make patients with certain risk factors such as age and procedure type aware of their higher revision risk as part of shared decision-making.

Does early return to theatre add value to rates of revision at 3 years in assessing surgeon performance for elective hip and knee arthroplasty? National observational study.

BACKGROUND: Joint replacement revision is the most widely used long-term outcome measure in elective hip and knee surgery. Return to theatre (RTT) has been proposed as an additional outcome measure, but how it compares with revision in its statistical performance is unknown. METHODS: National hospital administrative data for England were used to compare RTT at 90 days (RTT90) with revision rates within 3 years by surgeon. Standard power calculations were run for different scenarios. Funnel plots were used to count the number of surgeons with unusually high or low rates. RESULTS: From 2006 to 2011, there were 297 650 hip replacements (HRs) among 2952 surgeons and 341 226 knee replacements (KRs) among 2343 surgeons. RTT90 rates were 2.1% for HR and 1.5% for KR; 3-year revision rates were 2.1% for HR and 2.2% for KR. Statistical power to detect surgeons with poor performance on either metric was particularly low for surgeons performing 50 cases per year for the 5 years. The correlation between the risk-adjusted surgeon-level rates for the two outcomes was +0.51 for HR and +0.20 for KR, both p<0.001. There was little agreement between the measures regarding which surgeons had significantly high or low rates. CONCLUSION: RTT90 appears to provide useful and complementary information on surgeon performance and should be considered alongside revision rates, but low case loads considerably reduce the power to detect unusual performance on either metric.

Factors Associated With 30-Day Readmission After Primary Total Hip Arthroplasty: Analysis of 514 455 Procedures in the UK National Health Service.

IMPORTANCE: Thirty-day readmission to hospital after total hip arthroplasty (THA) has significant direct costs and is used as a marker of hospital performance. All-cause readmission is the only metric in current use, and risk factors for surgical readmission and those resulting in return to theater (RTT) are poorly understood. OBJECTIVE: To determine whether patient-related predictors of all-cause, surgical, and RTT readmission after THA differ and which predictors are most significant. DESIGN, SETTING, AND PARTICIPANTS: Analysis of all primary THAs recorded in the National Health Service (NHS) Hospital Episode Statistics database from 2006 to 2015. The effect of patient-related factors on 30-day readmission risk was evaluated by multilevel logistic regression analysis. The analysis comprised all acute NHS hospitals in England and all patients receiving primary THA. MAIN OUTCOMES AND MEASURES: Thirty-day readmission rate for all-cause, surgical (defined using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision primary admission diagnoses), and readmissions resulting in RTT. RESULTS: Across all hospitals, 514 455 procedures were recorded. Seventy-nine percent of patients were older than 60 years, 40.3% were men, and 59.7% were women. There were 30 489 all-cause readmissions (5.9%), 16 499 surgical readmissions (3.2%), and 4286 RTT readmissions (0.8%); 54.1% of readmissions were for surgical causes. Comorbidities with the highest odds ratios (ORs) of RTT included those likely to affect patient behavior: drug abuse (OR, 2.22; 95% CI, 1.34-3.67; P = .002), psychoses (OR, 1.83; 95% CI, 1.16-2.87; P = .009), dementia (OR, 1.57; 95% CI, 1.11-2.22; P = .01), and depression (OR, 1.52; 95% CI, 1.31-1.76; P < .001). Obesity had a strong independent association with RTT (OR, 1.46; 95% CI, 4.45-6.43; P < .001), with one of the highest population attributable fractions of the comorbidities (3.4%). Return to theater in the index episode was associated with a significantly increased risk of RTT readmission (OR, 5.35; 95% CI, 4.45-6.43; P < .001). Emergency readmission to the hospital in the preceding 12 months increased the risk of readmission significantly, with the association being most pronounced for all-cause readmission (for >2 emergency readmissions, OR, 2.33; 95% CI, 2.11-2.57; P < .001). Hip resurfacing was associated with a lower risk of RTT when compared with cemented implants (OR, 0.69; 95% CI, 0.54-0.88; P = .002) but for other types of readmission, implant type had no significant association with readmission risk. Increasing age and length of stay were strongly associated with all-cause readmission. CONCLUSIONS AND RELEVANCE: Many patient-related risk factors for surgical and RTT readmission differ from those for all-cause readmission despite the latter being the only measure in widespread use. Clinicians and policy makers should consider these alternative readmission metrics in strategies for risk reduction and cost savings.

Making strong cords from surgical sutures.

The authors present a simple and cost effective technique of preparing strong cords from surgical sutures. The technique requires suture material, a drill, a clip and it takes less than a minute to prepare. The mechanical strength of the cord obtained by this method was compared to the mechanical strength of a single suture. Cords containing eight thicknesses of the suture material failed at slightly under eight times the single suture strength. A loop made out of cords of number 2 Vicryl or Dexon failed at loads of more than 1000 N. The authors have found these cords extremely useful and effective for reconstruction of the dislocated acromio-clavicular joint and also for the fixation of trans-femoral osteotomies.

Pre-operative digital templating in cemented hip hemiarthroplasty for neck of femur fractures.

Pre-operative digital templating allows the surgeon to foresee any anatomical anomalies which may lead to intra-operative problems, and anticipate appropriate instruments and implants required during surgery. Although its role is well-established in successful elective total hip arthroplasty, little work has been done on its use in hip hemiarthroplasty in neck of femur fractures. We describe our initial experience of digital templating in 40 consecutive patients who have undergone cemented hip hemiarthroplasty, assessing templating accuracy between templated implant sizes to actual implant sizes. 81% of implanted heads were templated to within two head sizes, and 89% of implanted stems were templated to within two sizes. Although there was a moderately strong correlation of 0.52 between templated and actual head sizes, this correlation was not demonstrated in femoral stem sizes. Mean leg length discrepancy was -2.5mm (S.D. 8.5), and the mean difference in femoral offset between the operated and non-operated hip was -1mm (S.D. 4.4). Digital templating is a useful adjunct to the surgeon in pre-operative planning of hip hemiarthroplasty in the restoration of leg length and femoral offset. However, its accuracy is inferior to that of elective total hip arthroplasty.

Descent without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds.

The strong oxidant H2O2 is known to exist in solid form on Europa and is suspected to exist on several other Solar System worlds at temperatures below 200 K. However, little is known of the thermal chemistry that H2O2 might induce under these conditions. Here, we report new laboratory results on the reactivity of solid H2O2 with eight different compounds in H2O-rich ices. Using infrared spectroscopy, we monitored compositional changes in ice mixtures during warming. The compounds CH4 (methane), C3H4 (propyne), CH3OH (methanol), and CH3CN (acetonitrile) were unaltered by the presence of H2O2 in ices, showing that exposure to either solid H2O2 or frozen H2O+H2O2 at cryogenic temperatures will not oxidize these organics, much less convert them to CO2. This contrasts strongly with the much greater reactivity of organics with H2O2 at higher temperatures, and particularly in the liquid and gas phases. Of the four inorganic compounds studied, CO, H2S, NH3, and SO2, only the last two reacted in ices containing H2O2, NH3 making NH4+ and SO2 making SO(4)2- by H+ and e- transfer, respectively. An important astrobiological conclusion is that formation of surface H2O2 on Europa and that molecule's downward movement with H2O-ice do not necessarily mean that all organics encountered in icy subsurface regions will be destroyed by H2O2 oxidation.

The effect of new oral anticoagulants and extended thromboprophylaxis policy on hip and knee arthroplasty outcomes: observational study.

The efficacy and safety of the new oral anticoagulants (NOAC) and the benefits of extended duration thromboprophylaxis following hip and knee replacements remain uncertain. This observational study describes the relations between thromboprophylaxis policies following hip and knee replacements across England's NHS and patient outcomes between January 2008 and December 2011. From the national administrative database, we analyzed mortality, thromboembolic complications, emergency readmission, and bleeding rates for 201,418 hip and 230,282 knee replacements. There were no differences in outcomes for either LMWH or NOAC. We found no advantage in favor of any single anticoagulation policy or in changing policy. This study supports the American Academy of Orthopaedic Surgeons' recommendation that the choice and duration of thromboprophylaxis prophylaxis be decided by the treating surgeon.

Patient Satisfaction: Receiving a copy of the GP letter following fracture or elective orthopaedic clinic.

Following orthopaedic/fracture clinics at our hospital, patients now receive a copy of the letter summarizing an outpatient consultation that is sent to their General Practitioner. We undertook a patient satisfaction questionnaire to determine if patients found this change in practice beneficial. Of the 83 patients who had received this letter, most patients had read the letter (96%) and understood the content (90%). 13% were worried after having read the content and 86% found it helpful. Of the 40 patients who did not receive a copy, 32 (80%) specified that they would wish to in the future. The results support the new practice although it could be improved by identifying those who do not wish to be included thereby reducing costs.

Mortality and morbidity following hip fractures related to hospital thromboprophylaxis policy.

Chemical thromboprophylaxis has been shown to reduce the incidence of venous thromboembolism (VTE) for patients with fractures of the hip, but it is not known with certainty whether it use also reduces mortality. Using postal and telephone questionnaires we collected data from English National Health Service (NHS) hospitals about their thromboprophylaxis policy for hip fractures patients from April 2003 to April 2007. Using Hospital Episode Statistics (HES) we ascertained in-hospital mortality rates at 30 days and at one year following admission to hospital. Unplanned hospital readmission rates for all causes (including episodes of thromboembolism and bleeding) within 30 days (all years) and one year (2003 to 2005) were also established. A total of 150 hospitals were contacted and data gathered from 62 hospitals (response rate 41.3%) There were 255841 patients with neck of femur fractures during this five year period who were assessed for morbidity and mortality, and we correlat these with thromboprophylaxis policy. There was no significant difference in hospital readmission within 30 days, or diagnosis of thromboembolism or haemorrhage among hospitals with different thromboprophylaxis policies. The hospitals using low molecular weight heparin (LMWH) in half the dose recommended by the British National Formulary had significantly reduced mortality in-hospital (odds ratio (OR) 0.79, 95% CI 0.69-0.90, P=0.0006), at 30 days (OR 0.8 (0.70 - 0.92), P=0.001) and at one year (OR 0.89 (0.80 - 1.00), P=0.050), compared with those with no such policy. Our data suggest that the thromboprophylaxis regimen for patients with fracture neck of femur should be half dose LMWH for the duration of the hospital stay.

Decomposition of solid amorphous hydrogen peroxide by ion irradiation.

We present laboratory studies of the radiolysis of pure (97%) solid H2O2 films by 50 keV H+ at 17 K. Using UV-visible and infrared reflectance spectroscopies, a quartz-crystal microbalance, and a mass spectrometer, we measured the absolute concentrations of the H2O, O2, H2O2, and O3 products as a function of irradiation fluence. Ozone was identified by both UV and infrared spectroscopies and O2 from its forbidden transition in the infrared at 1550 cm(-1). From the measurements we derive radiation yields, which we find to be particularly high for the decomposition of hydrogen peroxide; this can be explained by the occurrence of a chemical chain reaction.