Tibial Slope Is Not Associated With Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design

BACKGROUND

The influence of tibial slope on tibial component migration following total knee arthroplasty has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement.

METHODS

Radiostereometric analyses at 6 visits over 2 years quantified implant migration for 200 cemented total knee arthroplasties. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with 1-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration.

RESULTS

The mean posterior tibial slope was 8.0° (standard deviation [SD] 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = .671) or anterior-posterior tilt migration (P = .704). There was no association between postoperative tibial slope and migration at 1 year postoperatively (P = .441 for MTPM migration, P = .570 for tilt migration), change in migration from 1 to 2 years (P = .951), or inducible displacement (P = .970 MTPM, P = .730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement.

CONCLUSIONS

Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment.

Video-based assessment (VBA) of an open, simulated orthopedic surgical procedure: a pilot study using a single-angle camera to assess surgical skill and decision making

BACKGROUND

Videos have been used in many settings including medical simulation. Limited information currently exists on video-based assessment in surgical training. Effective assessment tools have substantial impact on the future of training. The objectives of this study were as follows: to evaluate the inter-rater reliability of video-based assessment of orthopedic surgery residents performing open cadaveric simulation procedures and to explore the benefits and limitations of video-based assessment.

METHODS

A multi-method technique was used. In the quantitative portion, four residents participated in a Surgical Objective Structured Clinical Examination in 2017 at a quaternary care training center. A single camera bird's-eye view was used to videotape the procedures. Five orthopedic surgeons evaluated the surgical videos using the Ottawa Surgical Competency Operating Room Evaluation. Interclass correlation coefficient was used to calculate inter-rater reliability. In the qualitative section, semi-structured interviews were used to explore the perceived strengths and limitations of video-based assessment.

RESULTS AND DISCUSSION

The scores using video-based assessment demonstrated good inter-rater reliability (ICC = 0.832, p = 0.014) in assessing open orthopedic procedures on cadavers. Qualitatively, the strengths of video-based assessment in this study are its ability to assess global performance and/or specific skills, ability to reassess missed points during live assessment, and potential use for less common procedures. It also allows for detailed constructive feedback, flexible assessment time, anonymous assessment, multiple assessors and serves as a good coaching tool. The main limitations of video-based assessment are poor audio-video quality, and questionable feasibility for assessing readiness for practice.

CONCLUSION

Video-based assessment is a potential adjunct to live assessment in orthopedic open procedures with good inter-rater reliability. Improving audio-video quality will enhance the quality of the assessment and improve the effectiveness of using this tool in surgical training.

Cost comparison between spinal versus general anesthesia for hip and knee arthroplasty: an incremental cost study

PURPOSE

Wait list times for total joint arthroplasties have been growing, particularly in the aftermath of the COVID-19 pandemic. Increasing operating room (OR) efficiency by reducing OR time and associated costs while maintaining quality allows the greatest number of patients to receive care.

METHODS

We used propensity score matching to compare parallel processing with spinal anesthesia in a block room vs general anesthesia in a retrospective cohort of adult patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). We compared perioperative costs, hospital costs, OR time intervals, and complications between the groups with nonparametric tests using an intention-to-treat approach.

RESULTS

After matching, we included 636 patients (315 TKA; 321 THA). Median [interquartile range (IQR)] perioperative costs were CAD 7,417 [6,521-8,109], and hospital costs were CAD 10,293 [9,344-11,304]. Perioperative costs were not significantly different between groups (pseudo-median difference [MD], CAD -47 (95% confidence interval [CI], -214 to -130; P = 0.60); nor were total hospital costs (MD, CAD -78; 95% CI, -340 to 178; P = 0.57). Anesthesia-controlled time and total intraoperative time were significantly shorter for spinal anesthesia (MD, 14.6 min; 95% CI, 13.4 to 15.9; P < 0.001; MD, 15.9; 95% CI, 11.0 to 20.9; P < 0.001, respectively). There were no significant differences in complications.

CONCLUSION

Spinal anesthesia in the context of a dedicated block room reduced both anesthesia-controlled time and total OR time. This did not translate into a reduction in incremental cost in the spinal anesthesia group.

Activation of mitochondrial telomerase reverses relative lymphopenia post myocardial infarction: results from the randomised, double-blinded TACTIC phase IIa pilot trial

Background

Immune ageing is a phenomenon which includes lymphopenia, expansion of pro-inflammatory T-lymphocyte subsets and telomere shortening. While lymphopenia predicts mortality after myocardial infarction (MI), MI itself leads to both an increase in terminally differentiated memory CD8+ T-lymphocytes (CD8+ TEMRAs) and a decrease in telomere length. Activation of telomerase has been shown to ameliorate lymphopenia, and improve heart function after MI in mouse models. TA-65 is an oral telomerase activator, which may ameliorate immune ageing and improve outcome after MI.

Methods

This double-blinded, randomized placebo-controlled pilot study evaluated the use of TA-65 in 90 MI patients over 65 years, the average onset age for immune ageing. Patients were randomised to either TA-65 (16 mg daily, n=45) or placebo (n=45) for 12 months. The majority of patients underwent percutaneous coronary intervention (87%) or coronary artery bypass surgery (2%) as treatment for their index MI. The pre-defined primary endpoint was the proportion of CD8+ TEMRA T-lymphocytes at 12 months, a marker of immune ageing. A linear mixed effects model was used for the analysis.

Results

The proportion of CD8+ TEMRAs after 12 months did not differ between the 2 treatment groups, although only increased significantly in the placebo group (+2.2%, 95% CI: 0.14–4.24). TA-65 was well tolerated, with total adverse events lower in the treatment group (TA-65 vs. placebo group: n=130 vs. n=185). We observed at 12 months a 62% reduction in mean high-sensitivity CRP (hsCRP: TA-65 vs. placebo group: 1.1±0.9 vs. 2.9±6.4 mg/L) and a 15%-increase in mean peripheral blood lymphocytes in TA-65 after 12 months. In the whole sample, among those who were treated with TA-65 compared to Placebo, after 12 months peripheral blood lymphocytes increased (+285 cells /μl, 95% CI: 117–452). The latter was due to significant increases in the TA-65 group from baseline to 12 months across all major lymphocyte populations: CD3+ (+15%), CD4+ (+14%),CD8+ T-lymphocytes (+19%), B-lymphocytes (+17%) and natural killer cells (+12%), while no changes occurred in major lymphocyte populations in the placebo group over the course of the study.

Conclusion

In this randomised clinical trial, we found that while CD8+ TEMRAs were not significantly altered after 12 months, the telomerase activator TA-65 significantly increased all major lymphocyte subsets and substantially reduced hsCRP at 12 months in patients with MI. These findings suggest TA-65 holds great promise in potentially reducing inflammation while improving an age-related decline in major lymphocyte populations, thereby enhancing immunity. A larger, multicentre, powered phase IIb efficacy trial to examine the potential effect of TA-65 in prognosis and heart function after MI is therefore warranted.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): TA-Science, New York, USA

874 Impact of Covid-19 Measures on Surgical Site Infection Rate in Orthopaedic Patients

Aim

Rate of surgical site infections (SSI) in orthopaedic surgery is low but can have disastrous consequences. The aim of this study was to assess the impact of Covid-19 measures on the rate of SSI and subsequent readmissions in orthopaedic patients.

Method

Retrospective, observational study comparing rates of SSI in orthopaedic patients who underwent surgery prior to the Covid-19 lockdown versus that of patients who underwent surgery during the lockdown period. A total of 1151 patients were identified using electronic clinical records over two different time periods: 3 months pre Covid-19 lockdown (n=680) and 3 months during the Covid-19 lockdown (n=470). Patients were followed up for 1 year following their initial procedure. Primary outcome was readmission for SSI.

Results

The most commonly performed procedures were arthroplasty and manipulation under anaesthesia with 119 in lockdown vs 101 non-lockdown (p=0.001). The readmission rate was higher in the lockdown group with 61 (13%) vs 44 (6.5%) in the non-lockdown group (p &lt;0.001). However, the majority were due to other surgical complications such as dislocations. Interestingly, the SSI rates were very similar with 24 (5%) in lockdown vs 28 (4%) in non-lockdown (p=0.472). Twenty patients (4.2%) required a secondary procedure for their SSI in the lockdown group vs 24 (3.5%) in non-lockdown (p=0.381). Mortality rate was similar at 44 (9.3%) in lockdown vs 61 (9.0%; p=0.836).

Conclusion

Whilst Covid-19 precautions were associated with higher readmission rates, there was no significant difference in rate of SSI between the two groups.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Morbid Obesity and Severe Knee Osteoarthritis: Which Should Be Treated First?

BACKGROUND

There are limited prospective data, and conflicting retrospective data, providing guidance on how to optimally manage patients with morbid obesity and severe knee osteoarthritis. This study sought to review the effect of bariatric surgery on knee pain and knee surgery 30-day outcomes, as well as assess whether the sequence of bariatric and knee surgery has any effect on 30-day complications.

METHODS

A retrospective chart review of all patients undergoing laparoscopic sleeve gastrectomy (LSG) from July 2006 to July 2016 at a university hospital was performed. Patients with knee pain or knee surgery (pre- or post-LSG) were identified using bariatric and orthopedic clinic notes. Those who had improvement in knee pain following LSG resulting in removal from orthopedic surgery waitlist were identified. We also assessed surgical outcomes in patients undergoing knee arthroscopy or total knee arthroplasty (TKA) followed by LSG compared to patients undergoing LSG followed by knee arthroscopy or TKA.

RESULTS

During our study timeframe, 355 patients underwent LSG. Knee pain was documented in 150 (42.2%) patients, and orthopedic surgery consultation was completed for 57 (38.0%) patients with knee pain. Orthopedic intervention was performed prior to LSG for 24 patients and after LSG for 27 patients. Procedures were a combination of arthroscopy (18) and TKA (33). Six patients were removed from the waitlist for TKA following LSG due to resolution of symptoms. Order of interventions did not affect 30-day complications for patients undergoing LSG and arthroscopy (16% arthroscopy first, 0% LSG first, p = 0.43). A higher rate of LSG complications was noted in patients who underwent TKA prior to LSG (25% vs 0%, p = 0.04). There were no differences in TKA complications (8.3% TKA first, 4.8% LSG first, p = 1.00).

CONCLUSION

In a small number of patients with morbid obesity and severe knee osteoarthritis, orthopedic intervention can be delayed and potentially avoided by undergoing LSG. In our study, 6/57 (10.5%) of patients with orthopedic consultation prior to LSG saw resolution of symptoms of knee pain. Referral to bariatric surgery should be considered for patients with morbid obesity and severe knee osteoarthritis.

Variable effects of obesity on access to total hip and knee arthroplasty

Background

Obesity is an important comorbidity affecting outcomes after total joint arthroplasty. Consequently, surgeons may delay care of obese patients to first address obesity through different care pathways. The effect of obesity on patient wait times for total joint arthroplasty has not been explored. The purpose of this study was to evaluate the effect of obesity on access to total hip (THA) and knee (TKA) arthroplasty.

Methods

The study data set was constructed from the Nova Scotia Health Authority’s Horizon Patient Folder system and the Patient Access Registry Nova Scotia. Wait time was measured as days between the decision to treat and date of surgery. Body mass index (BMI) was calculated from a preoperative assessment, and patients were grouped into BMI categories. Multivariate log-linear regression was used to test for statistical differences, controlling for confounding factors.

Results

We observed longer wait times for TKA with increasing BMI weight class. Patients with BMIs greater than 50 had 34% longer waits than reference weight patients. However, THA recipients showed no statistical difference in wait times across weight categories. Furthermore, there was variability among surgeons in the wait times experienced by patients.

Conclusion

The finding of longer wait times for TKAs, but not THAs, among patients who were obese was unexpected. This shows the variable wait times for THA and TKA that patients who are obese can experience with different surgeons. It is important to understand the variability in wait times so that efforts to standardize the patient experience can be accomplished.

Role of CMV-serostatus and CX3CR1 on lymphocyte kinetics and left ventricular remodelling in patients with acute myocardial infarction

Background

Patients with latent cytomegalovirus (CMV) infection have higher rates of adverse cardiovascular outcomes, but the reasons for this remain elusive. CMV-induced changes to T-lymphocyte populations, with a proliferation of CMV-specific, CX3CR1+ effector memory cells, may contribute. Effector T-cells are associated with cardiovascular mortality in CMV positive patients, and ischaemia-reperfusion injury after ST-elevation myocardial infarction (STEMI) and primary percutaneous coronary intervention (pPCI).

Purpose

To investigate the effect of CMV status on lymphocyte kinetics and cardiac MRI (cMRI) parameters in 52 STEMI patients receiving pPCI, and examine the prognostic relevance of pre-reperfusion lymphocyte count in a large cohort.

Methods

We retrospectively analysed the association between pre-reperfusion lymphocyte count, troponin, and long-term survival in 4874 consecutive STEMI patients. Using flow cytometry, we analysed lymphocyte kinetics in 52 STEMI patients, of known CMV status, during and after pPCI. We assessed the impact of CMV status on infarct size, left-ventricular (LV) function and microvascular obstruction with cMRI in the first week after reperfusion in 101 patients. Repeat cMRI at 12 weeks, to assess LV remodelling, was obtained in 48 patients.

Results

Pre-reperfusion lymphopenia is an independent predictor of mortality over 7.5 years (hazard ratio for lowest vs highest quartile: 2.0; 95% CI 1.7–2.4; p&lt;0.001), and is associated with higher admission troponins (p&lt;0.001 for lowest vs second-lowest quartile), suggesting lymphocyte count falls prior to reperfusion in response to myocardial injury. CMV positive patients had more cytotoxic T-cells, strongly expressing the fractalkine receptor, CX3CR1. In CMV positive patients these cells fell dramatically by 90 minutes post-reperfusion, and dropped more sharply in patients with extensive microvascular obstruction on cMRI (p≤0.05 in all effector subsets). CX3CR1 expression was lower at 90 minutes post-reperfusion than at 24 hours (return to physiological expression) in all effector T-cell subsets. All subsets lost a similar proportion of their 24-hour value, but consistently lost a larger proportion in CMV positive patients (−27% in CMV+, −18% in CMV−; p=0.007). CX3CR1 expression falls in the presence of fractalkine, and we hypothesise that membrane-bound fractalkine is induced more strongly in CMV positive patients, as soluble fractalkine levels were similar. At 12 weeks, LV remodeling was worse in CMV positive patients (change in end-diastolic volume: +10.7ml vs −6.1ml; p=0.02).

Conclusions

Lymphopenia occurs prior to reperfusion in STEMI, and predicts long-term mortality. Effector T-cells drop substantially after reperfusion only in CMV positive patients, likely mediated by CX3CR1-fractalkine interaction, and this is associated with adverse cMRI findings. Remodeling is worse in CMV positive patients at 12 weeks post-STEMI.

Lymphocytes, troponin and survival

Funding Acknowledgement

Type of funding source: Public Institution(s)

Graphical-based multivariate analysis for knee joint clinical and kinematic data correlation assessment

A large amount of data including joint kinematics, joint kinetics, clinical and functional measurements constitutes the clinical gait analysis basis which is a process whereby quantitative gait information are collected to aid in clinical decision-making. Therefore, better understanding the relationship between the biomechanical and clinical data for the knee osteoarthritis (OA) patient is for a relevant importance. It's the purpose of this paper, which aims to analyze and visualize the correlation structure between biomechanical characteristics and clinical symptoms, and thus to provide an additional knowledge from the coupling of these parameters that will be useful for the pathology assessment of knee-joint disease in the end-staged knee OA patients. We perform two multivariate statistical approaches, first, a Canonical Correlation Analysis (CCA) to assess the multivariate association and, second, a graphical- based representation of the multivariate correlation to better understand the association between these multivariate data. Results show the usefulness of using such multivariate approaches to highlight association and specific correlation structure between the features and to extract meaningful information.

Health experiences of asylum seekers and refugees in Wales

Key messages

Improving health equity is key to realising Wales’ ambition to become a Nation of Sanctuary. Peer Researchers enabled participation by sanctuary seekers and revealed useful findings to steer future policy and practice.

Higher periprosthetic fracture rate associated with use of modern uncemented stems compared to cemented stems in femoral neck fractures

INTRODUCTION:

Hemiarthroplasty is the preferred treatment for displaced femoral neck fractures in elderly patients. Recently, short tapered-wedge cementless stems have increasingly been used in this population. However, historic data has consistently shown higher rates of periprosthetic fracture with uncemented stems in hip fracture patients. This study aims to evaluate the rate of periprosthetic fracture requiring re-operation and all-cause mortality between cemented and uncemented femoral stem designs including more recent short tapered-wedge cementless stems in hip fracture patients.

METHODS:

A retrospective chart and radiographic review of patients received bipolar hemiarthroplasty for femoral neck fractures from 2010-2016. Patients biologically (age ≥ 65 years) or physiologically (American Society of Anesthesiologists (ASA) class ≥ 3) elderly were eligible. The uncemented group was subdivided into tapered-wedge stems (a broach only system) and reamed uncemented stems. The primary outcome was periprosthetic fracture requiring re-operation.

RESULTS:

We included 657 patients in total, with 296 and 361 patients in the uncemented and cemented stem groups respectively. In the uncemented group there were 197 tapered-wedge and 99 reamed uncemented stems. There was a significantly higher rate of periprosthetic fracture requiring re-operation in the uncemented group (3.0% vs. 0.6%) ( p ≤ 0.05). There were no significant differences in rates of all-cause mortality, infection or all-cause re-operation.

CONCLUSIONS:

Compared to modern uncemented femoral stem designs, cemented stems yield lower rates of periprosthetic fracture requiring re-operation, without increasing risk of all-cause mortality. Tapered-wedge stems had similar rates of re-operation due to periprosthetic fracture as reamed uncemented stems.

Abstract P6-14-07: Not presented

This abstract was not presented at the conference.

Citation Format: Lai J, Antill Y, Richardson G, Vereker M, David S. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-14-07.

Risk factors for infection, revision, death, blood transfusion and longer hospital stay 3 months and 1 year after primary total hip or knee arthroplasty

BACKGROUND

Total joint replacement (TJR) is increasingly performed in older patients with more comorbidities, who are considered at higher risk for postoperative complications. We aimed to identify and calculate the odds ratio of the risk factors for infection, revision and death 3 months and 1 year after TJR as well as for postoperative blood transfusion and longer hospital stay.

METHODS

We analyzed all primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) cases in Nova Scotia between Apr. 1, 2000, and Mar. 31, 2014, as identified from the Discharge Abstract Database. We used the Charlson Comorbidity Index as a surrogate measure of comorbidities. We used hospital and physician billings data and Nova Scotia Vital Statistics data to identify the postoperative events in this cohort.

RESULTS

A total of 10 123 primary THA and 17 243 primary TKA procedures were performed during the study period. The mean patient age was 66.1 (standard deviation 11.7) years and 67.1 (standard deviation 9.3) years, respectively. With THA, the risk of infection was higher in patients with heart failure and those with diabetes. For TKA, liver disease and blood transfusion were associated with a higher risk of infection. Revision rates were higher among patients with hypertension and those with paraparesis/hemiparesis for THA, and among patients with metastatic disease for TKA. Significant risk factors for death included metastatic disease, older age, heart failure, myocardial infarction, dementia, rheumatologic disease, renal disease, blood transfusion and cancer. Multiple medical comorbidities and older age were associated with higher rates of blood transfusion and longer hospital stay.

CONCLUSION

We have identified the risk factors associated with higher rates of postoperative complications and longer hospital stay after TJR. The results enable individualized risk stratification during the preoperative consultation.

Knee motion and muscle activation patterns are altered in hip osteoarthritis: The effect of severity on walking mechanics

BACKGROUND

Knee function is impaired in individuals with moderate hip osteoarthritis. How this extends to those undergoing total hip arthroplasty is unknown despite the common requirement for knee arthroplasty in this population. The study purpose was to determine whether sagittal plane knee joint movements and quadriceps and hamstring activation patterns differ between individuals with either moderate or severe unilateral hip osteoarthritis, and between ipsilateral and contralateral knees.

METHODS

20 individuals with moderate osteoarthritis and 20 with severe osteoarthritis were recruited. Sagittal knee motion and surface electromyograms from the hamstrings and quadriceps were collected during treadmill walking at a self-selected speed. Principal component analysis captured amplitude and temporal sagittal plane motion and EMG waveform features. Student's t-tests and Analysis of Variance determined between group differences and within/between group leg differences.

FINDINGS

The severe groups' contralateral knee was in greater flexion at initial contact and demonstrated a movement profile of a longer stance phase (p < 0.001). The severe group had reduced sagittal plane knee motion (p < 0.0001); more so in the ipsilateral knee (p < 0.0001). The severe group had greater hamstring (p = 0.009) and quadriceps activation (p < 0.001) overall, specifically mid-stance quadriceps bilaterally (p = 0.002). Ipsilateral sagittal plane knee motion was reduced in both groups. Compared with those with moderate osteoarthritis, individuals with severe osteoarthritis walk with reduced sagittal plane knee motion bilaterally, suggesting prolonged contralateral stance, and elevated mid-stance hamstring and quadriceps activation.

INTERPRETATION

Altered kinematics and muscle activity could contribute to a greater mechanical demand on the contralateral knee in those with more severe hip osteoarthritis.

Impact of specialist rehabilitation services on hospital length of stay and associated costs

BACKGROUND

Provision of specialist rehabilitation services in North Yorkshire and Humberside may be suboptimal. Local commissioning bodies need to prioritise investments in health care, but previous studies provide limited evidence to inform the decision to expand existing services on the basis of cost-effectiveness. We examine the impact of specialist rehabilitation services in the subregion on hospital length of stay (LoS) and associated costs compared to routine care.

METHODS

Comparison of hospital LoS and associated costs in centres with greater access (Hull) and limited access (i.e. routine care, York and Northern Lincolnshire), to specialist rehabilitation services for patients with complex disabilities following illness or injury, using Hospital Episodes Statistics data.

RESULTS

Average LoS and duration costs by Healthcare Resource Group (HRG) were lower for the majority of patients with greater access to specialist rehabilitation compared to routine care. Difference in LoS between groups widened with level of complexity within each HRG. For the more frequent HRG codes, the LoS difference was as high as 34 days longer for York compared to Hull and £7900 more costly.

CONCLUSION

Rehabilitation patients within York and Northern Lincolnshire areas appear to have longer LoS and higher associated costs compared to those admitted to the Hull Trust. This analysis suggests that specialist rehabilitation may be cost saving compared to routine care and supports the case for expansion of the existing services to improve coverage in the area.

The cost-effectiveness of follow-up strategies after cancer treatment: a systematic literature review

INTRODUCTION

The cost of treatment and follow-up of cancer patients in the UK is substantial. In a budget-constrained system such as the NHS, it is necessary to consider the cost-effectiveness of the range of management strategies at different points on cancer patients' care pathways to ensure that they provide adequate value for money.

SOURCES OF DATA

We conducted a systematic literature review to explore the cost-effectiveness of follow-up strategies of patients previously treated for cancer with the aim of informing UK policy. All papers that were considered to be economic evaluations in the subject areas described above were extracted.

AREAS OF AGREEMENT

The existing literature suggests that intensive follow-up of patients with colorectal disease is likely to be cost-effective, but the opposite holds for breast cancer.

AREAS OF CONTROVERSY

Interventions and strategies for follow-up in cancer patients were variable across type of cancer and setting. Drawing general conclusions about the cost-effectiveness of these interventions/strategies is difficult.

GROWING POINTS

The search identified 2036 references but applying inclusion/exclusion criteria a total of 44 articles were included in the analysis. Breast cancer was the most common (n = 11) cancer type followed by colorectal (n = 10) cancer. In general, there were relatively few studies of cost-effectiveness of follow-up that could influence UK guidance. Where there was evidence, in the most part, NICE guidance broadly reflected this evidence.

AREAS TIMELY TO DEVELOP RESEARCH

In terms of future research around the timing, frequency and composition of follow-ups, this is dependent on the type of cancer being considered. Nevertheless, across most cancers, the possibility of remote follow-up (or testing) by health professionals other than hospital consultants in other settings appears to warrant further work.

Prediction of haematocrit in dried blood spots from the measurement of haemoglobin using commercially available sodium lauryl sulphate

Background When preparing dried blood spots (DBSs), haematocrit (Hct) can affect the ability of the blood to spread through the filter paper, thus resulting in varying quantities of sample being measured when fixed subpunches of the DBSs are taken. It may be important to predict the sample Hct to correct volume differences. Methods Blood (10  µL) was applied to Perkin Elmer 226® paper. The samples ( n = 165) were allowed to dry for 24 h, and the entire blood spots were cut out. Subpunch analysis was also performed on blood spots prepared from 75  µL EDTA blood, taking 6 mm subpunches centrally and peripherally from the spots ( n = 59). The spots were eluted with 100  µL water, and a 10  µL aliquot of lysate was added to sulfolyser reagent (80  µL) in a microtitre plate. Hb was measured at 550 nm using an ELISA plate reader. DBS samples were compared against blood samples measured on a routine Sysmex XN-9000 analyser. Results The Passing and Bablock regression showed Hct (DBS-predicted) = 0.99 Hct (Sysmex) -0.02, R²= 0.87. Intra-assay imprecision measured at Hct values of 0.27, 0.40 and 0.52, gave CVs of 4.1%, 2.8% and 4.2%, respectively. Inter-assay imprecision showed CVs of 6.2%, 5.2% and 4.2%, respectively. DBS samples were stable for up to two days at 60℃, one month at room temperature and six months at 4℃. Conclusion This method provides a simple and fast estimation of predicted Hct in dried blood spots.

Exploratory examination of the utility of demoralization as a diagnostic specifier for adjustment disorder and major depression

OBJECTIVE

Demoralization, a state of lowered morale and poor coping, has a prevalence of 13-18% among patients with advanced cancer. We surveyed clinicians' perspectives of the utility of "with demoralization" as a diagnostic specifier for adjustment and depressive disorders.

METHOD

Using comparative clinical vignettes in a field survey, clinicians from a range of disciplines were asked their perception of the utility of diagnosis and treatment options. Response frequencies were compared using Cochran's Q and McNemar's tests, with sensitivity and specificity rated against expert rankings of diagnosis. Analysis of variance and paired t-tests examined significant differences in ratings of utility.

RESULTS

Vignettes were assessed by 280 clinicians; 77% supported utility of the category 'adjustment disorder with demoralization' compared to 33% supporting 'adjustment disorder with anxiety' (McNemar test, p<0.001), while 83% supported the utility of 'with demoralization' for major depressive episode, matching 83% perceiving utility for 'with melancholia.' Sensitivity and specificity ratings were 77% and 94% for adjustment disorder with demoralization and 83% and 91% for major depression with demoralization.

CONCLUSION

Clinicians perceived the specifier 'with demoralization' to deepen diagnostic understanding, treatment choice, and ability to communicate with clinicians and patients, particularly for the category of adjustment disorder with demoralization.

Cost-effectiveness of integrated collaborative care for comorbid major depression in patients with cancer

OBJECTIVES

Comorbid major depression is associated with reduced quality of life and greater use of healthcare resources. A recent randomised trial (SMaRT, Symptom Management Research Trials, Oncology-2) found that a collaborative care treatment programme (Depression Care for People with Cancer, DCPC) was highly effective in treating depression in patients with cancer. This study aims to estimate the cost-effectiveness of DCPC compared with usual care from a health service perspective.

METHODS

Costs were estimated using UK national unit cost estimates and health outcomes measured using quality-adjusted life-years (QALYs). Incremental cost-effectiveness of DCPC compared with usual care was calculated and scenario analyses performed to test alternative assumptions on costs and missing data. Uncertainty was characterised using cost-effectiveness acceptability curves. The probability of DCPC being cost-effective was determined using the UK National Institute for Health and Care Excellence's (NICE) cost-effectiveness threshold range of £ 20,000 to £ 30,000 per QALY gained.

RESULTS

DCPC cost on average £ 631 more than usual care per patient, and resulted in a mean gain of 0.066 QALYs, yielding an incremental cost-effectiveness ratio of £ 9549 per QALY. The probability of DCPC being cost-effective was 0.9 or greater at cost-effectiveness thresholds above £ 20,000 per QALY for the base case and scenario analyses.

CONCLUSIONS

Compared with usual care, DCPC is likely to be cost-effective at the current thresholds used by NICE. This study adds to the weight of evidence that collaborative care treatment models are cost-effective for depression, and provides new evidence regarding their use in specialist medical settings.

Reduced aggression and foraging efficiency of invasive signal crayfish (Pacifastacus leniusculus) infested with non-native branchiobdellidans (Annelida: Clitellata)

BACKGROUND

Biological invasions are a principal threat to global biodiversity and identifying the determinants of non-native species' success is a conservation priority. Through their ability to regulate host populations, parasites are increasingly considered as important in determining the outcome of species' invasions. Here, we present novel evidence that the common crayfish ecto-symbiont, Xironogiton victoriensis (Annelida: Clitellata) can affect the behaviour of a widespread and ecologically important invader, the signal crayfish (Pacifastacus leniusculus).

METHODS

To assess the signal crayfish-X. victoriensis relationship naïve crayfish were infested with an intensity of worms typically observed under natural conditions. Over a 10-week period the growth rate and survivorship of these animals was monitored and compared to those of uninfested counterparts. Complementary dyadic competition and foraging experiments were run to assess the behaviour of infested compared to uninfested animals. These data were analysed using General Linear Models and Generalized Linear Mixed Models.

RESULTS

Whilst X. victoriensis did not affect the growth rate or survivorship of signal crayfish under laboratory conditions, infested animals were significantly less aggressive and poorer foragers than uninfested individuals.

CONCLUSIONS

Through reducing aggression and foraging efficiency, infestation with X. victoriensis may disrupt the social structure, and potentially growth rate and/or dispersal of afflicted crayfish populations, with potential effects on their invasion dynamics. This is important given the widespread invasive range of crayfish and their functional roles as ecosystem engineers and keystone species.

Intraoperative passive knee kinematics during total knee arthroplasty surgery

Surgical navigation systems for total knee arthroplasty (TKA) surgery are capable of capturing passive three-dimensional (3D) angular joint movement patterns intraoperatively. Improved understanding of patient-specific knee kinematic changes between pre and post-implant states and their relationship with post-operative function may be important in optimizing TKA outcomes. However, a comprehensive characterization of the variability among patients has yet to be investigated. The objective of this study was to characterize the variability within frontal plane joint movement patterns intraoperatively during a passive knee flexion exercise. Three hundred and forty patients with severe knee osteoarthritis (OA) received a primary TKA using a navigation system. Passive kinematics were captured prior to (pre-implant), and after prosthesis insertion (post-implant). Principal component analysis (PCA) was used to capture characteristic patterns of knee angle kinematics among patients, to identify potential patient subgroups based on these patterns, and to examine the subgroup-specific changes in these patterns between pre- and post-implant states. The first four extracted patterns explained 99.9% of the diversity within the frontal plane angle patterns among the patients. Post-implant, the magnitude of the frontal plane angle shifted toward a neutral mechanical axis in all phenotypes, yet subtle pattern (shape of curvature) features of the pre-implant state persisted.

Reliability, validity, and responsiveness of the Western Ontario and McMaster Universities Osteoarthritis Index for elderly patients with a femoral neck fracture

BACKGROUND

The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) has been extensively evaluated in groups of patients with osteoarthritis, yet not in patients with a femoral neck fracture. This study aimed to determine the reliability, construct validity, and responsiveness of the WOMAC compared with the Short Form-12 (SF-12) and the EuroQol 5D (EQ-5D) questionnaires for the assessment of elderly patients with a femoral neck fracture.

METHODS

Reliability was tested by assessing the Cronbach alpha. Construct validity was determined with the Pearson correlation coefficient. Change scores were calculated from ten weeks to twelve months of follow-up. Standardized response means and floor and ceiling effects were determined. Analyses were performed to compare the results for patients less than eighty years old with those for patients eighty years of age or older.

RESULTS

The mean WOMAC total score was 89 points before the fracture in the younger patients and increased from 70 points at ten weeks to 81 points at two years postoperatively. In the older age group, these scores were 86, 75, and 78 points. The mean WOMAC pain scores before the fracture and at ten weeks and two years postoperatively were 92, 76, and 87 points, respectively, in the younger age group and 92, 84, and 93 points in the older age group. Function scores were 89, 68, and 79 points for the younger age group and 84, 71, and 73 points for the older age group. The Cronbach alpha for pain, stiffness, function, and the total scale ranged from 0.83 to 0.98 for the younger age group and from 0.79 to 0.97 for the older age group. Construct validity was good, with 82% and 79% of predefined hypotheses confirmed in the younger and older age groups, respectively. Responsiveness was moderate. No floor effects were found. Moderate to large ceiling effects were found for pain and stiffness scales at ten weeks and twelve months in younger patients (18% to 36%) and in the older age group (38% to 53%).

CONCLUSIONS

The WOMAC showed good reliability, construct validity, and responsiveness in both age groups of elderly patients with a femoral neck fracture who had been physically and mentally fit before the fracture. The instrument is suitable for use in future clinical studies in these populations.

CLINICAL RELEVANCE

The results are based on two clinical trials. The questionnaires used concern pure, clinically relevant issues (ability to walk, climb stairs, etc.). Moreover, the results can be used for future research comparing clinical outcomes (or treatments) for populations with a femoral neck fracture.

Metal-on-metal hip surface replacement

Metal-on-metal resurfacing of the hip (MoMHR) has enjoyed a resurgence in the last decade, but is now again in question as a routine option for osteoarthritis of the hip. Proponents of hip resurfacing suggest that its survival is superior to that of conventional hip replacement (THR), and that hip resurfacing is less invasive, is easier to revise than THR, and provides superior functional outcomes. Our argument serves to illustrate that none of these proposed advantages have been realised and new and unanticipated serious complications, such as pseudotumors, have been associated with the procedure. As such, we feel that the routine use of MoMHR is not justified.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):17–21.

Noninfarct related artery embolic protection during primary PCI

A 66-year old man presented with antero-lateral STEMI. An ulcerated plaque and thrombus were seen in the proximal LAD. We were unable to pass a thrombectomy catheter down the LAD. To avoid embolisation of debris a Spider FX distal protection device was placed into the circumflex artery. Following stent implantation the patient developed chest pain with inferolateral ST depression. Thrombus was extracted from the circumflex artery within the distal protection device. Noninfract related artery distal protection during primary PCI may be an appropriate safeguard where thrombectomy is not possible in an infarct-related left coronary branch.

The role of perceived injustice in the prediction of pain and function after total knee arthroplasty

Emerging evidence suggests that the appraisal of pain and disability in terms of justice-related themes contributes to adverse pain outcomes. To date, however, research on the relation between perceived injustice and pain outcomes has focused primarily on individuals with musculoskeletal injuries. The primary aim of this study was to investigate the role of perceived injustice in the prediction of pain and disability after total knee arthroplasty (TKA). The study sample consisted of 116 individuals (71 women, 45 men) with osteoarthritis of the knee scheduled for TKA. Participants completed measures of pain severity, physical disability, perceptions of injustice, pain catastrophizing, and fear of movement before surgery, and measures of pain and disability 1 year after surgery. Prospective multivariate analyses revealed that perceived injustice contributed modest but significant unique variance to the prediction of postsurgical pain severity, beyond the variance accounted for by demographic variables, comorbid health conditions, presurgical pain severity, pain catastrophizing, and fear of movement. Pain catastrophizing contributed significant unique variance to the prediction of postsurgical disability. The current findings add to a growing body of evidence supporting the prognostic value of perceived injustice in the prediction of adverse pain outcomes. The results suggest that psychosocial interventions designed to target perceptions of injustice and pain catastrophizing before surgery might contribute to more positive recovery trajectories after TKA.

Changes in the functional flexion axis of the knee before and after total knee arthroplasty using a navigation system

Long term satisfaction of patients with total knee arthroplasty (TKA) has lagged behind that of total hip arthroplasty. One possible reason is the failure of the artificial joint to recreate natural kinematics of the knee. This study evaluated the pre and post implant functional flexion axis in the knees of 285 total knee arthroplasty patients using a surgical navigation system. Results showed that post-implant there was less femoral rollback early in flexion on the lateral side of the joint than pre-implant. Designing future generations of knee implants to allow for this motion may give patients a more 'natural' feeling knee and may benefit outcomes.

Cost-effectiveness of combining systematic identification and treatment of co-morbid major depression for people with chronic diseases: the example of cancer

BACKGROUND

Co-morbid major depression occurs in approximately 10% of people suffering from a chronic medical condition such as cancer. Systematic integrated management that includes both identification and treatment has been advocated. However, we lack information on the cost-effectiveness of this combined approach, as published evaluations have focused solely on the systematic (collaborative care) treatment stage. We therefore aimed to use the best available evidence to estimate the cost-effectiveness of systematic integrated management (both identification and treatment) compared with usual practice, for patients attending specialist cancer clinics.

METHOD

We conducted a cost-effectiveness analysis using a decision analytic model structured to reflect both the identification and treatment processes. Evidence was taken from reviews of relevant clinical trials and from observational studies, together with data from a large depression screening service. Sensitivity and scenario analyses were undertaken to determine the effects of variations in depression incidence rates, time horizons and patient characteristics.

RESULTS

Systematic integrated depression management generated more costs than usual practice, but also more quality-adjusted life years (QALYs). The incremental cost-effectiveness ratio (ICER) was £11,765 per QALY. This finding was robust to tests of uncertainty and variation in key model parameters.

CONCLUSIONS

Systematic integrated management of co-morbid major depression in cancer patients is likely to be cost-effective at widely accepted threshold values and may be a better way of generating QALYs for cancer patients than some existing medical and surgical treatments. It could usefully be applied to other chronic medical conditions.

I can't get no satisfaction after my total knee replacement: rhymes and reasons

Satisfaction is increasingly employed as an outcome measure for a successful total knee replacement (TKR). Satisfaction as an outcome measure encompasses many different intrinsic and extrinsic factors related to a person's experience before and after TKR. The Swedish Knee Arthroplasty Registry has previously demonstrated on a large population study that 17% of TKR recipients are not satisfied with their TKR outcome. This finding has been replicated in other countries. Similar significant factors emerged from these registry studies that are related to satisfaction. It would appear that satisfaction is better after more chronic diseases and whether the TKR results in pain relief or improved function. Importantly, unmet pre-operative expectations are a significant predictor for dissatisfaction following a TKR. It may be possible to improve rates by addressing the issues surrounding pain, function and expectation before embarking on surgery.