Patient function is poorly characterised following revision TKA. Modern semi-constrained implants are suggested to offer high levels of function, however, data is lacking to justify this claim. 52 consecutive aseptic revision TKA procedures performed at a single centre were prospectively evaluated; all were revision of a primary implant to a Triathlon total stabiliser prosthesis. Patients were assessed pre-operatively and at 6, 26, 52 and 104 weeks post-op. Outcome assessments were the Oxford Knee Score (OKS), range of motion, pain rating scale and timed functional assessment battery. Analysis was by repeated measures ANOVA with post-hoc Tukey HSD 95% simultaneous confidence intervals as pairwise comparison. Secondary analysis compared the results of this revision cohort to previously reported primary TKA data, performed by the same surgeons, with identical outcome assessments at equivalent time points. Mean age was 73.23 (SD 10.41) years, 57% were male. Mean time since index surgery was 9.03 (SD 5.6) years. 3 patients were lost to follow-up. All outcome parameters improved significantly over time (p <0.001). Post-hoc analysis demonstrated that all outcomes changed between pre-op, 6 week and 26 weeks post-op assessments. No difference was seen between primary and revision cohorts in OKS (p = 0.2) or pain scores (p=0.19). Range of motion and functional performance was different between groups over the 2 year period (p=0.03), however this was due to differing pre-operative scores, post-hoc analysis showed no difference between groups at any post-operative time point. Patients undergoing aseptic revision TKA with semi-constrained implants made substantial improvements in OKS, pain scores, knee flexion, and timed functional performance, with the outcomes achieved comparable to those of primary TKA. High levels of function can be achieved following revision knee arthroplasty, which may be important considering the changing need for, and demographics of, revision surgery.
Service industry metrics (the net promoter score) are being introduced as a measure of UK healthcare satisfaction. Lower limb arthroplasty, as a ‘service’, scores comparably with the most successful commercial organisations. Satisfaction with care is important to both the patient and the payer. The Net Promoter Score, widely used in the service industry, has been recently introduced to the UK National Health Service as an overarching metric of patient satisfaction and to monitor performance. This questionnaire asks ‘customers’ if they would recommend a service or products to others. Scores range from −100 (everyone is a detractor) to +100 (everyone is a promoter). In industry, a positive score is well regarded, with those over 50 regarded as excellent. Our aims were to assess net promoter scores for joint arthroplasty, to compare these scores with direct measures of patient satisfaction, and to evaluate which factors contributed to net promoter response.Summary Statement
Background
Using current analysis/methodology, new implant technology is unlikely to demonstrate a large enough change in patient function to impact on the cost-effectiveness of the procedure. Cost effectiveness is an increasingly important metric in today's healthcare environment, and decisions surrounding which arthroplasty prosthesis to implant are not exempt from such health economic concerns. Quality adjusted life years (QALYs) are the typical assessment tool for this type of evaluation. Using this methodology, joint arthroplasty has been shown to be cost effective, however studies directly comparing the QALY achieved by differing prostheses are lacking.Summary Statement
Purpose
This study investigates the relationship between direct measurement of outcome and patient report of that outcome via the OKS. The stability of this relationship over time following surgery is also assessed. 183 TKA patients were assessed pre-operatively and at 6, 26 and 52 weeks post-op. Oxford Knee Score was obtained along with measures of pain intensity, knee flexion, lower limb power and timed functional assessment. Correlation of performance variables with the OKS was assessed, and regression analysis performed on those that formed significant associations. Significance was accepted at p = 0.05.INTRODUCTION
METHODS
The aim was to perform a cost-utility analysis of total joint replacement in the current environment. Arthritis is a disabling condition that leads to long-term deterioration in quality of life. Total joint replacement, despite being one of the greatest advances in medicine in the modern era, has come under recent scrutiny. The National Health Service (NHS) has competing demands and resource allocation is challenging in times of economic restraint. Patients undergoing total hip (n=348) and knee arthroplasty (n=323), from January to July 2010, were entered into a prospective arthroplasty database. A health utility score was derived from the Euroqol (EQ-5D) score preoperatively, and at one year, and was combined with individual life expectancy to derive the Quality-Adujusted-Life-Years (QALYs) gained. Predicted need for revision surgery was Incorporated in the model. The 2011–12 Scottish Tariff was used. Two-way analysis of variance was used to compare QALYs gained between procedures, while controlling for baseline differences. The number of QALYs gained was higher in THR versus TKR (6.53 vs 4.04 years, p<0.001). The cost per QALY for THR was £1371 (95% CI £1194 to £1614) compared with £2101 (£1762 to £2620) for TKR. Predictors of an increase in QALYs gained were poorer health prior to surgery (p<0.001) and younger age (p<0.001). General health (EQ-5D VAS) showed greater improvement in THR versus TKR (p<0.001). This study provides up to date cost-effectiveness data for total joint replacement. THR and TKR are both extremely clinically and cost-effective interventions, with costs that compare favourably with other medical interventions (e.g. laparoscopic hernia repair vs open: £55,548 per QALY; CHD primary prevention with statins: £21,000).
Many prosthetic design changes have been introduced in attempt to improve outcomes following TKA; however there is no consensus as to whether these changes confer benefits to patients. This study aimed to assess whether patients treated with a modern implant design had an enhanced patient outcome compared to a traditional model in a double blind randomised controlled trial. 212 consecutive patients were prospectively randomised to receive either a modern (Triathlon) or a traditional (Kinemax) TKA (both Stryker Orthopaedics). 6 surgeons at a single unit performed all procedures in a standardised manner. A single researcher, blinded to implant allocation, performed all assessments. Patients were assessed pre-operatively, and at 6, 26, 52 weeks post-surgery with the Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, goniometry, timed functional assessment, lower limb power (Leg Extensor Power Rig) and pain numerical rating scales (NRS). Change in scores and between group differences were assessed with Two-Way Repeated Measures ANOVAs.Introduction
Methods
We switched our antibiotic prophylaxis for elective hip and knee surgery from cefuroxime to flucloxacillin with single dose gentamicin in order to reduce the incidence of C. Diff diarrhoea. More patients subsequently appeared to develop acute kidney injury (AKI). During a twelve month period we examined the incidence of AKI sequentially in 198 patients undergoing elective hip or knee surgery: cefuroxime (n = 48); high dose flucloxacillin (median 8g) (n = 52); low dose flucloxacillin (median 4g) (n = 46); and cefuroxime again (n = 52).Background
Methods
End-stage osteoarthritis is characterised by pain and reduced physical function, for which total knee arthroplasty (TKA) is recognised to be a highly effective treatment. Most implants are multi radius in design, though modern kinematic theory suggests a single flexion/extension axis is located in the femur. A recently launched TKA implant (Triathlon, Stryker US), is based on this theory, adopting a single radius of curvature femoral component. It is hypothesised that this design allows better function, and specifically, that it results in enhanced efficiency of the quadriceps group through a longer patello-femoral moment arm. Change in power output was compared between single and multi radius implants as part of a larger ongoing randomised controlled trial to benchmark the new implant. Power output was assessed using a Leg Extensor Power Rig, well validated for use with this population, pre-operatively and at 6, 26 and 52 weeks post-operatively in 101 Triathlon and 82 Kinemax implants. All patients were diagnosed with osteoarthritis, and drawn from a single centre. Output was reported as maximal wattage (W) generated in a single leg extension, and expressed as a proportion of the contralateral limb power output to act as an internal control. The results are shown in the table below. Two-way repeated measures ANOVA demonstrated a significant effect of TKA on the quadriceps power output, F = 249.09, p = <0.001 and also a significant interaction of the implant group on the output F = 11.33, p = 0.001. Independent samples t-tests of between group differences at the four assessment periods highlighted greater improvement in the single radius TKA group at all post-operative assessments (p <0.03), see table. The theoretical enhanced quadriceps efficiency conferred by single radius design was found in this study. Power output was significantly greater at all post-operative assessments in the single radius compared to the multi radius group. This difference was particularly relevant at early 6 week and 1 year assessment. Lower limb power output is known to link positively to functional ability. The results support the hypothesis that TKAs with a single radius design have enhanced recovery and better function.
SIGN guidelines advise the use of flucloxacillin and gentamicin instead of cefuroxime as antibiotic prophylaxis for elective hip and knee arthroplasty. It is our impression that this change in practice has been associated with an increased risk of acute kidney injury (AKI). During a twelve month period we examined the incidence of AKI sequentially in four groups of patients: cefuroxime prophylaxis (n = 46); high dose flucloxacillin (5-8g) with single shot gentamicin (n = 50); low dose flucloxacillin (1-4 g) with single shot gentamicin (n = 45); and finally cefuroxime again (n = 52). There were no statistically significant differences by chi-square tests for age, gender, operation (hip or knee), ASA, anaesthesia, baseline serum creatinine, hypertension, diabetes or pre-operative medication. The proportion of patients in each antibiotic group with any form of AKI by RIFLE criteria was: cefuroxime group 1 (9%), high dose flucloxacillin (52%), low dose flucloxacillin (22%), cefuroxime 2 (14%) (p < 0.0001 by chi-square test). Odds ratios (OR) for AKI derived from a multivariate logistic regression model and assigning an OR of 1 to cefuroxime group 1 was: high dose flucloxacillin 14.5 (95% CI, 4.2, 50.2); low dose flucloxacillin 3.0 (0.8-10.9) and cefuroxime group 2 1.9 (0.5, 7.4). Three patients in the high dose flucloxacillin group required temporary haemodialysis. We have shown a strong association between high dose prophylactic flucloxacillin and subsequent development of AKI. We have no reason to believe that this was confounded by any of the co-variates we measured.
Recovery of muscle strength following Total Knee Replacement (TKR) is variable, and can affect the resultant function of the patient. Satellite cells are undifferentiated myogenic precursors considered to be muscle stem cells that lie quiescently around the muscle fibre. These cells repair damaged fibres and have the potential to generate new muscle fibres. Therefore, theoretically, they could be associated with the variation in muscle recovery following surgery. We hypothesised that the recovery of muscle strength following knee replacement in a given patient would be influenced by the underlying number of satellite cells in that patient. 20 patients undergoing TKR were recruited from the waiting list of a single consultant. A muscle biopsy was taken at the time of surgery from the distal quadriceps. This was fixed in paraffin wax, and sections obtained. Satellite cells were identified with a primary mouse antibody for Pax7 - a cytoplasmic protein marker - and an immunofluorescent goat anti-mouse secondary. Slides were counterstained with DAPI to stain the myonuclei. The positive staining index (PSI) was calculated (number of satellite cells/total number of myonuclei x 100). Recovery of muscle (quadriceps) strength was assessed using the leg extensor power-rig (LegRig) pre-operatively, at 6 and 26 weeks post-operatively. Statistical analysis was performed using the Minitab version 15 software, the level of significance was set as p = 0.05.Introduction
Methods
Surgery for pelvic or acetabular fractures carries a high risk of deep-vein thrombosis (DVT). Reports indicate that fondaparinux is a more effective thromboprophylactic agent than low molecular weight heparin (LMWH) after major orthopaedic surgery. We prospectively evaluated a new protocol for DVT prophylaxis using fondaparinux. One hundred and eight patients with pelvic or acetabular fractures were randomised to receive either fondaparinux or enoxaparin. Specific review points included the primary end-point of clinical deep vein thrombosis (DVT) or pulmonary embolism (PE) and any evidence of adverse effects such as bleeding or allergic reactions. Two patients that received enoxaparin were found to have a DVT (3%) and one patient died from a PE (1%). There was no documented DVT or PE in patients that received fondaparinux. The mean number of units of blood transfused was significantly higher in the enoxaparin group and this was significant post-operatively (p<0.05). The current study supports that post-operative fondaparinux, in patients with pelvic and acetabular fractures, is more effective and equally safe to enoxaparin.Patients and methods
Results
Anthrax is extremely rare in the western world but is endemic to areas of south and central Asia. In early 2010 an outbreak was identified in heroin-injecting intravenous drug users in the United Kingdom and Europe. Afghanistan is currently the principal source of heroin which reaches the United Kingdom. When anthrax occurs, cutaneous disease accounts for over 95% of cases. At least 47 cases with 13 deaths have been confirmed so far. We present three cases presenting during this time with marked swelling, one resulting in compartment syndrome but all with an absence of the expected cutaneous appearances. We suggest that rather than cutaneous anthrax, these patients represent a new subcutaneous presentation of anthrax.
Without thromboprophalaxis, the recorded incidence of deep venous thrombosis (DVT) in pelvic fracture varies between 35% and 61%. The incidence of pulmonary embolism (PE) is reported to be 2–10% and death subsequently occurs in 0.5–4% of patients. With preventative measures the incidence of clinically significant DVT has been reported as low as 0.5%. The primary aim of this study is to look into the efficacy of Enoxaparin in preventing clinically significant DVT and PE in patients with pelvic and acetabular fracture. The secondary aim is to investigate the effect of prolonged pre-operative exposure to Enoxaparin on operative and post-operative bleeding. Sixty-four patients with pelvic and acetabular fractures were reviewed retrospectively between 2000–2005. Patients with coagulopathies were excluded. 40mg Enoxaparin was administered daily following haemodynamic evaluation and continued thereafter until discharge. Blood loss was measured using 3 indicators: volume of blood transfused, difference in pre and post operative Hb, and amount of blood collected in surgical drains. The incidence of clinically significant DVT was 2.9% (2 cases). There was no confirmed incidence of PE. 47% of patients were operated on within a week of admission (Group A), 40% within 1–2 weeks (Group B) and 13% in over 2 weeks (Group C). The group with the most prolonged pre-operative exposure to Enoxaparin: Group C, required the least transfused blood (A: 4.8units, B: 2.0units C: 1.3units), bled the least into drains (A:310ml, B:253ml and C:212ml) and had the smallest post-operative fall in Hb (A:2.2, B:2.0, C:1.9). The low incidence of clinically detectable DVT in the study confirms that Enoxaparin is an effective method for reducing the incidence of significant thrombotic events. Prolonged pre-operative administration of Enoxaparin does not pre-dispose patients to an increased risk of operative and post-operative bleeding.
