Outcomes for patients with acute illnesses may be affected by the day of the week they present to hospital. Policy makers state this ‘weekend effect’ to be the main reason for pursuing a change in consultant weekend working patterns. However, it is uncertain whether such a phenomenon exists for elective orthopaedic surgery. This study investigated whether a ‘weekend effect’ contributed to adverse outcomes in patients undergoing elective hip and knee replacements. Retrospectively collected data was obtained from our institutions electronic patient records. Using univariate analysis, we examined potential risk factors including; Age, Sex, ASA Grade, Comorbidities, as well as the day of the week surgery was undertaken. Subsequent multivariate analyses identified covariate-adjusted risk factors, associated with prolonged hospital stays. 30-day mortality data was assessed according to the day of the week surgery was performed.Background
Methods
Outcomes for patients with acute illnesses may be affected by the day of the week they present to hospital. Policy makers state this ‘weekend effect’ to be the main reason for pursuing a change in consultant weekend working patterns. However, it is uncertain whether such a phenomenon exists for elective orthopaedic surgery. This study investigated whether a ‘weekend effect’ contributed to adverse outcomes in patients undergoing elective hip and knee replacements. Retrospectively collected data was obtained from our institutions electronic patient records. Using univariate analysis, we examined potential risk factors including; Age, Sex, ASA Grade, Comorbidities, as well as the day of the week, hospital admission and surgery occurred. Subsequent multivariate analyses identified covariate- adjusted risk factors, associated with prolonged hospital stays. 30-day mortality data was assessed according to the day of the week surgery was performed. 892 patients underwent arthroplasty surgery from 01/09/2014 till the 31/08/2015. 457 patients had a total hip and 435 had a total knee replacement. 814 patients (91.3%) underwent surgery during the week, while 78 (8.7%) had surgery on a Saturday. There was no difference in the average Length of Stay (LOS) between groups (5.0, 2.6 versus 5.0, 3.4, p=0.95), and weekend surgery was not associated with a LOS greater than 4 days. The two variables found to be associated with a prolonged LOS were; increasing age (RR) 1.02 (95% CI: 1.01–1.03, p<0.001) and an ASA score of 2, (RR) 1.6 (95% CI: 1.15 − 2.20, p=0.005). There was one death in a patient who was ASA III, and who underwent surgery on a Monday. There is no ‘weekend effect’ for elective orthopaedic surgery. Changes in consultant weekend working patterns are unlikely to have any effect on mortality or LOS for elective orthopaedic patients.
Financial and human cost effectiveness is an increasing evident outcome measure of surgical innovation. Considering the human element, the aim is to restore the individual to their “normal” state by sparing anatomy without compromising implant performance. Gait lab studies have shown differences between different implants at top walking speed, but none to our knowledge have analysed differing total hip replacement patients through the entire range of gait speed and incline to show differences. The purpose of this gait study was to 1) determine if a new short stem femoral implant would return patients back to normal 2) compare its performance to established hip resurfacing and long stem total hip replacement (THR) implants. 110 subjects were tested on an instrumented treadmill (Kistler Gaitway), 4 groups (short-stem THR, long-stem THR, hip resurfacing and healthy controls) of 28, 29, 27, and 26 respectively. The new short femoral stem patients (Furlong Evolution, JRI) were taken from the ongoing Evolution Hip trial that have been tested on the treadmill minimum 12months postop. The long stem total hip replacements and hip resurfacing groups were identified from our 800+ patient treadmill database, and only included with tests minimum 12 months postop and had no other joint disease or medical comorbidities which would affect gait performance. All subjects were tested through their entire range of gait speeds and incline after having a 5 minute habituation period. Speed were increased 0.5kmh until maximum walking speed achieved and inclines at 4kmh for 5,10,15%. At all incremental intervals of speed 10seconds ere collected, including vertical ground reaction forces (normalized to body mass), center of pressure and temporal measurements were for both limbs (fs=100Hz). Symmetry Index(SI) were calculated on a range of features comparing leg with implanted hip to the contralateral normal hip. Group means for each feature for each subject group were compared using an analysis of variance (ANOVA) with Tukey post-hoc test with significance set at α=0.05.Introduction
Method
Financial and human cost effectiveness is an increasing evident outcome measure of surgical innovation. Considering the human element, the aim is to restore the individual to their “normal” state by sparing anatomy without compromising implant performance. Gait lab studies have shown differences between different implants at top walking speed, but none to our knowledge have analysed differing total hip replacement patients through the entire range of gait speed and incline to show differences. The purpose of this gait study was to 1) determine if a new short stem femoral implant would return patients back to normal 2) compare its performance to established hip resurfacing and long stem total hip replacement (THR) implants. 110 subjects were tested on an instrumented treadmill (Kistler Gaitway, Amherst, NY), 4 groups (short-stem THR, long-stem THR, hip resurfacing and healthy controls) of 28, 29, 27, and 26 respectively. The new short femoral stem patients (Furlong Evolution, JRI) were taken from the ongoing Evolution Hip trial that have been tested on the treadmill with minimum 12months postop. The long stem total hip replacements and hip resurfacing groups were identified from out 800 patient gait database. They were only chosen if they were 12 months postop and had no other joint disease or medical comorbidities which would affect gait performance. All subjects were tested through their entire range of gait speeds and incline after having a 5 minute habituation period. Speed intervals were at 0.5kms increments until maximum walking speed achieved and inclines at 4kms for 5, 10, 15%. At all incremental intervals of speed, the vertical component of the ground reaction forces, center of pressure and temporal measurements were collected for both limbs with a sampling frequency of 100Hz. Body weight scaling was applied to correct for mass differences and a symmetry index to compare the implanted hip to the contralateral normal hip. All variables for each subject group were compared to each other using an analysis of variance (ANOVA) with Tukey post hoc test with significance set at α=0.05. The four experimental groups were reasonably matched for demographics and the implant groups for PROMs. Hip resurfacing had a clear top walking speed advantage, but when assessing the symmetry index on all speeds and incline, all groups were not significantly different. Push-off and step length was statistically less favourable for the short/long THR group (p=0.005–0.05) depending on speed/incline. The primary aim of this study was determine if implant design affected gait symmetry and performance. Interestingly, irrespective of implant design, symmetry with regards to weight acceptance, impulse, push-off and step length was returned to normal when comparing to healthy controls. However individual implant performance on the flat and incline, showed inferior (
Outcomes following large joint arthroplasty are influenced by the accuracy of implant placement. Patient specific (PS) technology has been used in knee arthroplasty surgery however, its application in total hip arthroplasty remains relatively unexplored. We investigated whether conventional or PS guides, resulted in a more accurate reconstruction of the pre-operative head centre position.Introduction
Aims
Femoral component design is a key part of hip arthroplasty performance. We have previously reported that a hip resurfacing offered functional improved performance over a long stem. However resurfacing is not popular for many reasons, so there is a growing trend towards shorter femoral stems, which have the added benefit of ease of introduction through less invasive incisions. Concern is also developing about the impact of longer stems on lifetime risk of periprosthetic fracture, which should be reduced by the use of a shorter stem. For these reasons, we wanted to know whether a shorter stem offered any functional improvement over a conventional long stem. We surmised that longer stems in hip implants might stiffen the femoral shaft, altering the mechanical properties. From our database of over 800 patients who have been tested in the lab, we identified 95 patients with a hip replacement performed on only one side, with no other lower limb co-morbidities, and a control group: 19 with long stem implant, age 66 ± 14 (LONG) 40 with short stem implant, age 69 ± 9 (SHORT) 26 with resurfacing, age 60 ± 8 (RESURF) 43 healthy control with no history of arthroplasty, age 59 ± 10 (CONTROL) All groups were matched for BMI and gender. Participants were asked to walk on an instrumented treadmill. Initially a 5 minute warm up at 4 km/h, then tests at increasing speed in 0.5 km/h increments. Maximum walking speed was determined by the patients themselves, or when subjects moved from walking to running. Ground reaction forces (GRF) were measured in 20 second intervals at each speed. Features were calculated based on the mean GRF for each trial, and on symmetry measures such as first peak force (heel strike), second peak force (toe-off), the rate at which the foot was loaded and unloaded, and step length.Introduction
Materials and Methods
A fractured hip is the commonest cause of injury related death in the UK. Prompt surgery has been found to improve pain scores and reduce the length of hospital stay, risk of decubitus ulcer formation and mortality rates. The hip fracture Best Practice Tariff (BPT) aims to improve these outcomes by financially compensating services, which deliver hip fracture surgery within 36 hours of admission. Ensuring that delays are reserved for patients with conditions which compromise survival, but are responsive to medical optimisation, would facilitate enhanced outcomes and help to achieve the 36-hour target. We aimed to identify medical conditions associated with patients failing to achieve the 36-hour cut off, and evaluated whether these were justified by calculating their associated mortality risk. Prospectively collected data from the National Hip Fracture Database (NHFD) and inpatient hospital records and blood results from a single major trauma centre were obtained. Complete data sets from 1361 patients were available for analysis. Medical conditions contributing to surgical delay beyond the BPPT (Best Practice Tariff Target) 36-hour cut off, were identified and analysed using univariate and multivariate regression analyses, whilst adjusting for covariates. The mortality risk associated with each factor contributing to surgical delay was then calculated using univariate and hierarchical regression techniques.Introduction
Methods
A recent PRCT failed to demonstrate superiority of HRA over THA at low speeds. Having seen HRA walk much faster, we wondered if faster walking speed might reveal larger differences. We therefore asked two simple questions: Does fast or uphill walking have an effect on the observed difference in gait between limbs implanted with one HRA and one THA? If there is a difference in gait between HRA and THA implanted legs, which is more normal?
There were 3 females and 6 males in the study group, who had a mean age of 67 (55–76) vs the control group 64 (53–82, p = 0.52). The BMIs of the two groups did not differ significantly (28 v 25, p = 0.11). The mean average oxford score of included patients was 44 (36–48). Radiographs of all subjects were examined to ensure that implanted components were well fixed. The mean time from THA operation to gait assessment was 4 years (1–17 yrs) and that for HRA was 6 years (0.7–10 yrs, p = 0.31). Subjects in this study had a mean TWS of 6.8 km/hr (5–9.5), and a mean TWI of 19 degrees (10–25 degrees).INTRODUCTION
METHODS
Cam type femoroacetabular impingement (FAI) may lead to osteoarthritis (OA)[1]. In 2D studies, an alpha angle greater than 55° was considered abnormal however limitations of 2D alpha angle measurement have led to the development of 3D methods [2–4]. Failure to completely address the bony impingement lesions during surgery has been the most common reason for unsuccessful hip arthroscopy surgery [5]. Robotic technology has facilitated more accurate surgery in comparison to the conventional means. In this study we aim to assess the potential application of robotic technology in dealing with this technically challenging procedure of cam sculpting surgery. CT scans of three patients' hips with severe cam deformity (A, B and C models) were obtained and used to construct 3D dry bone models. A 3D surgical plan was made in custom written software. Each 3D plan was imported into the Acrobot Sculptor robot and bone resection was carried out. In total, 42 femoral models were sculpted (14/subset), thirty of which were performed by a single operator and the remaining 12 femurs were resected by two other operators. CT of the pre/post resected specimens was segmented and a 3D alpha angle and head neck ratios were measured [3–4] and compared using Mann-Whitney U test. Coefficient of variation (CV) was used to determine the degree of variation between the mean and maximum observed alpha angles for inter and intra observer repeatability.Introduction:
Methods:
The combination of patient-specific “just-in-time” implant manufacture and robotic technology has not yet been reported. The robot enables accurate placement of anatomically-matched implants. It should be cost-effective, simplify the procedure, and reduce instrumentation. The aims of this study were to determine whether the procedure was safe, radiographically accurate, and comparable in time and cost to conventional arthroplasty. All patients over 3 months post-op were included. Component position, orientation and size were determined from CT scans by the surgeon prior to manufacture. The implants were inserted using the Sculptor robot, which is supplied free of cost (Savile Row, Stanmore Implants, UK). Following registration, bone was milled away using a high-speed burr under haptic control of the robot. The implants were cemented and a mobile bearing inserted. Patients were followed up clinically and radiographically. Oxford and EQ-5D scores were obtained. Costs of the implant, instruments, and consumables were calculated and compared to published data for conventional UKA and TKA.Background
Methods
