Abstract

Abstract

Abstract

Sound management decisions are critical to outcomes in revision arthroplasty. Aiming to improve outcomes, revision networks facilitate speciality trained, high volume surgeons, share experience and best practice, contributing to decision making within and away from their base hospital. We have reported the early clinical experience of East Midlands Specialist Orthopaedic Network (EMSON). In this paper we report beneficial clinical effects, both demonstrable and unquantifiable supporting the process.

Using the UK HES database of revisions, performed before and after EMSON was established, (April 2011 – March 2018), data from EMSON hospitals were compared to all other hospitals in the same time-period. Primary outcome was re-revision surgery within 1 year. Secondary outcomes were re-revision, complications within first two years and median LOS.

57,621 RTHA and 33,828 RTKA procedures were involved with around 1,485 (2.6%) and 1,028 (3.0%) respectively performed within EMSON. Re-revision THA rates, within 1 year, in EMSON were 7.3% and 6.0% with re-revision knee rates 11.6% and 7.4%, pre- and post-intervention. Re-revision rates in the rest England in the same periods were 7.4% to 6.8% for hips and 11.7% to 9.7% for knees. This constituted a significant improvement in 1-year re-revision rates for EMSON knees. (β = −0.072 (−0.133 to −0.01), p = 0.024). The reduction in hip re-revision did not reach statistical significance. Secondary outcomes showed a significant improvement for 1 and 2-year RTHA complication rates.

Re-revision rates for RTKA and complication rates for RTHA improved significantly after the introduction of EMSON. Other outcomes studied also improved to a greater extent in the network hospitals. While anecdotal experience with networks is positive, the challenge in collating data to prove clinic benefit should not be underestimated. Beyond the formal process, additional communication, interaction, and support has immeasurable benefit in both elective and emergency scenarios.

Hip and knee revisions continue to increase in number and complexity. With an understanding that revisions have a high re-revision rate, the importance of correct decisions made at the index procedure, is paramount for patients and surrounding health care economy.

Since January 2015, East Midlands Specialist Orthopaedic Network, (set up on a ‘hub-and-spoke’ model), has allowed all revisions performed within our region, (5 hospitals with a 4 million population), to be discussed at a weekly ‘web’ conference. Integrated radiology allows clinical information to be reviewed remotely at each hospital. Chaired by specialist revision surgeons, with other surgeons, a microbiologist and radiology, vascular, plastics opinions available as required, a formal management plan is ‘signed off’ by the chair and returned to referring institution. We present prospective data of Network activities.

To January 2018, 1007 cases have been referred by 18 consultants from 5 hospitals. A change in proposed plan was seen in 48% cases. (40% involved technique and exposure advice; 18% involved surgical inventory; 22% further investigation; 11% microbiological input; 9% other miscellaneous advice) Few (5%) patients were transferred directly. We also identified 20% increase in outpatient referrals to the ‘hub’.

The network is an excellent tool for discussing complex cases, supporting surgeons in smaller units. A significant number of alterations in plan are made with a few patients transferred directly. We feel the network can only enhance care and are working now to identify exactly how it has affected clinical outcomes. We encourage others to adopt this approach.

Infection following total hip or knee arthroplasty is a serious complication. We noted an increase in post-operative infection in cases carried out in a temporary operating theatre. We therefore compared those cases performed in standard and temporary operating theatres and examined the deep periprosthetic infection rates.

A total of 1233 primary hip and knee arthroplasties were performed between August 2012 and June 2013. 44% were performed in temporary theatres. The two groups were matched for age, sex, BMI and ASA grade.

The deep infection rate for standard operating theatres was 0/684 (0%); for temporary theatres it was 8/539 (1.5%); p=0.001.

Use of a temporary operating theatre for primary hip and knee arthroplasty was associated with an unacceptable increase in deep infection. We do not advocate the use of these theatres for primary joint arthroplasty.

Introduction

Between 2005 and 2010, the number of revision hip arthroplasties rose by 49.1%, and revision knee arthroplasties by 92.1%. This number is predicted to rise by 31% and 332% respectively by 2030.

In March 2014, NHS England invited bids to run a pilot revision network. Nottingham Elective Orthopaedic Service (NEOS) was successful and the East Midlands Specialist Orthopaedic Network (EMSON) runs on a ‘hub-and-spoke’ model.

Background

Dislocation is a major complication following total hip arthroplasty (THA). Aetiology is multi-factorial, but increasing femoral head size may result in lower dislocation rates. The latest England and Wales National Joint Registry (NJR) annual report has highlighted a statistically significant increase in the use of femoral heads of size 36mm+ from 5% in 2005 to 26% in 2009, together with an increase in the use of the posterior approach. The aim of this study was to determine whether national dislocation rates have fallen over the same period.

Background

Medical complications and death are rare events following elective orthopaedic surgery. Diagnostic and operative codes are routinely collected on every patient admitted to English NHS hospitals. This is the first study investigating rates of these events following total joint replacement (TJR) on a national scale.

Background

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Background

In 2011 20% of intracapsular fractured neck of femurs were treated with an uncemented hemiarthroplasty in the English NHS. National guidelines recommend cemented implants, based on evidence of less pain, better mobility and lower costs. We aimed to compare complications following cemented and uncemented hemiarthroplasty using the national hospital episode statistics (HES) database in England.

Background

Medical complications and death are rare events following elective orthopaedic surgery. Diagnostic and operative codes are routinely collected on every patient admitted to hospital in the English NHS (hospital episode statistics, HES). This is the first study investigating rates of these events following total joint replacement (TJR) on a national scale in the NHS.

Background

A recent Cochrane review has shown that total shoulder arthroplasty (TSA) seems to offer an advantage in terms of shoulder function over hemiarthroplasty, with no other obvious clinical benefits. This is the first study to compare complication rates on a national scale.

Introduction

Unlike the NJR, no surgeon driven national database currently exists for ligament surgery in the UK and therefore information on outcome and adverse event is limited to case series.

Introduction

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Background

Total Knee Replacement (TKR) is technically demanding, time consuming and has higher complication rates in super obese (BMI>45) patients. Bariatric surgery can be considered for such patients prior to TKR although its effect on complications is unknown.

Summary

We report a large study of 331 patients at two years post operation who were prospectively randomised to receive either a rotating platform or a fixed bearing knee replacement of an otherwise identical design.

Introduction

Previous studies comparing cruciate retaining (CR) and cruciate sacrificing - posterior stabilised (PS) TKRs have failed to demonstrate a difference in outcomes based on numbers of patients recruited.

This large study compares clinical outcomes in groups having PS and CR TKR and reports the results at 1 and 2 years post-operatively.

Aim

The aim of the study was to assess the impact of a self aligning unidirectional mobile tibial bearing and the use of a patella button on lateral patella release rates within a knee system using a common femoral component for both the fixed and mobile variants.

Background: Diagnostic and operative codes are routinely collected on every patient admitted to National Health Service (NHS) hospitals in England and Wales (hospital episode statistics, HES). The data allows for linkage of post-operative complications and primary operative procedures, even when patients are re-admitted following a successful discharge. Morbidity and mortality data on foot and ankle surgery (F& A) has not previously been available in large numbers for NHS patients.

Methods: All HES data for a 44-month period prior to August 2008 was analysed and divided into four groups – hindfoot fusion, ankle fracture surgery, ankle replacement and a control group. The control group was of first metatarsal osteotomy, which is predominantly day case surgery where no above ankle cast is used. The incidence of pulmonary embolism (PE) and all cause mortality (MR) within 90 days, and a return to theatre (RTT, as a complication of the index procedure) within 30 days was calculated for each group.

Results: 7448 patients underwent a hindfoot fusion. PE, RTT and MR were 0.11%, 0.11% and 0.12% respectively. 58732 patients had operative fixation of an ankle fracture. PE, RTT and MR were 0.16%, 0.08% and 0.35%. 1695 patients had an ankle replacement. PE, RTT and MR were 0.06%, 0.35% and zero. 35206 patients underwent a first metatarsal osteotomy. PE, RTT and mortality rates were 0.02%, 0.01% and 0.03%.

Discussion: There is controversy regarding the use of venous thrombo-embolic (VTE) prophylaxis in foot and ankle surgery. Non-fatal PE in F& A surgery has previously been reported as 0.15%. NICE guidelines recommend low molecular weight heparin (LMWH) for all inpatient orthopaedic surgery. 94% of F& A surgeons prescribe LMWH to post operative elective inpatients in plaster according to a previous British Orthopaedic foot and ankle society survey. VTE events, RTT and mortality rates for all groups were extremely low, including inpatient procedures requiring prolonged immobilisation. We question the widespread use of LMWH.

Arthroscopy of the knee is one of the most commonly performed orthopaedic procedures worldwide. Large-volume outcome data have not previously been available for English NHS patients. Prospectively collected admissions data, routinely collected on every English NHS patient, were analysed to determine the rates of complications within 30 days (including re-operation and re-admission), 90-day symptomatic venous thromboembolism and all-cause mortality. There were 301 701 operations performed between 2005 and 2010 – an annual incidence of 9.9 per 10 000 English population. Of these, 16 552 (6%) underwent ligament reconstruction and 106 793 (35%) underwent meniscal surgery. The 30-day re-admission rate was 0.64% (1662) and 30-day wound complication rate was 0.26% (677). The overall 30-day re-operation rate was 0.40% (1033) and the 90-day pulmonary embolism rate was 0.08% (230), of which six patients died. 90-day mortality was 0.02% (47). Age < 40 years, male gender and ligament reconstruction were significantly associated with an increased rate of 30-day re-admission and unplanned re-operation. In addition, a significant increase in 30-day admission rates were seen with Charlson comorbidity scores of 1 (p = 0.037) and ≥ 2 (p <  0.001) compared with scores of 0, and medium volume units compared with high volume units (p < 0.001).

Complications following arthroscopy of the knee are rare. It is a safe procedure, which in the majority of cases is performed as day case surgery. These data can be used for quality benchmarking, in terms of consent, consultant re-validation and individual unit performance.

Increased femoral head size may reduce dislocation rates following total hip replacement. The National Joint Registry for England and Wales has highlighted a statistically significant increase in the use of femoral heads ≥ 36 mm in diameter from 5% in 2005 to 26% in 2009, together with an increase in the use of the posterior approach. The aim of this study was to determine whether rates of dislocation have fallen over the same period. National data for England for 247 546 procedures were analysed in order to determine trends in the rate of dislocation at three, six, 12 and 18 months after operation during this time. The 18-month revision rates were also examined.

Between 2005 and 2009 there were significant decreases in cumulative dislocations at three months (1.12% to 0.86%), six months (1.25% to 0.96%) and 12 months (1.42% to 1.11%) (all p < 0.001), and at 18 months (1.56% to 1.31%) for the period 2005 to 2008 (p < 0.001). The 18-month revision rates did not significantly change during the study period (1.26% to 1.39%, odds ratio 1.10 (95% confidence interval 0.98 to 1.24), p = 0.118). There was no evidence of changes in the coding of dislocations during this time.

These data have revealed a significant reduction in dislocations associated with the use of large femoral head sizes, with no change in the 18-month revision rate.

Background: Diagnostic and operative codes are routinely collected on every patient admitted to hospital in England and Wales (hospital episode statistics, HES). Linked data allows post-operative complications to be associated with the primary operative procedure, even if patients are re-admitted following a successful discharge. Morbidity and mortality data on shoulder surgery have not previously been available in large numbers.

Methods: All HES data for a 42-month was analysed and divided into three groups – elective shoulder replacement (total or hemiarthroplasty), shoulder arthroscopy (all procedures), and proximal humerus fracture surgery (internal fixation or replacement). Incidence of pulmonary embolism (PE), deep venous thrombosis (DVT) and mortality within 90 days was established.

Results: For elective shoulder replacement (10735 patients), 90-day DVT, PE and mortality rates were 0.07%, 0.11% and 0.36% respectively. Mortality in patients over 75 years was 0.9%. For arthroscopic procedures (66344 patients), 90-day DVT, PE and mortality rates were 0.01%, 0.01% and 0.03%. For proximal humerus fracture surgery (internal fixation or replacement, 4968 patients) 90-day DVT, PE and mortality rates were 0.20%, 0.38% and 2.98%. Mortality in patients over 75 years old was 6.6%.

Discussion: Venous thromboembolic (VTE) prophylaxis is rarely used for upper limb surgery. PE and mortality rates for shoulder replacement and proximal humerus fracture surgery are lower those for patients receiving chemical prophylaxis after hip replacement. Further investigation into the cause of high mortality rates following fracture surgery in patients over 75 years old is required. VTE prophylaxis may be required in this age group.

Summary: This study compares the outcomes of a large series of 683 cruciate sacrificing (PS) and cruciate retaining (CR) TKRs at minimum 2 years follow-up. Patients with a PS component showed a greater improvement in the pain and knee components of the American Knee Society Score at both 1 and 2 years post-operatively and also demonstrated a greater improvement in knee flex-ion at both time points.

Introduction: Excellent clinical results have been reported with both PS and CR TKR designs. A number of randomised trials comparing the two techniques have failed to demonstrate a difference in outcomes based on the numbers of patients recruited.

It is hypothesised that cruciate retention in total knee arthroplasty may result in improved kinematics of the knee by maintaining the femoral rollback seen in the normal knee, resulting in improved function. This study compares clinical outcomes in groups having PS and CR total knee arthroplasty and report the results at 1 and 2 years post-operatively.

Methods: A total of 683 patients undergoing TKR surgery were consecutively enrolled in a prospective multi-centre study with 2 arms. In the first arm patients receiving a PS component were randomised to receive either a mobile bearing (176 patients) or fixed bearing (176 patients) implant. In the second arm, patients receiving a CR component were randomised to receive either a mobile bearing (161 patients) or fixed bearing (170 patients) implant. All patients were assessed pre-operatively and at one and two years postoperatively using standard tools (Oxford, AKSS, Patellar Score) by independent nurse specialists. The data from the 2 arms of the trial were then analysed to compare differences between PS and CR implants.

Results: Patients with a PS component showed a greater improvement in the pain component of the AKSS at 1 year (p=0.0003) and at 2 years (p=0.0085) post-op.

Patients with a PS also showed a greater improvement in the AKSS knee score at 1 (p=0.0001) and 2 (p=0.001) years.

Knee flexion improvement was also greater in the PS group at 1 (p=0< 0.0001) and 2 (p=0.0035) years.

PS knees also achieved better outcomes in these variables in the mobile and fixed subgroups.

There were no other significant differences in the scores between the two groups at any stage.

Conclusion: This study reports on a large prospective multi-centre series of PS and CR TKRs. Improvements in pain and knee components of the AKSS score and knee flexion at both 1 and 2 years follow-up were greater in PS knees. Although this difference was statistically significant, differences in real terms were relatively small.

Diagnostic and operative codes are routinely collected for every patient admitted to hospital in the English NHS. Data on post-operative complications following foot and ankle surgery have not previously been available in large numbers. Data on symptomatic venous thromboembolism events and mortality within 90 days were extracted for patients undergoing fixation of an ankle fracture, first metatarsal osteotomy, hindfoot fusions and total ankle replacement over a period of 42 months. For ankle fracture surgery (45 949 patients), the rates of deep-vein thrombosis (DVT), pulmonary embolism and mortality were 0.12%, 0.17% and 0.37%, respectively. For first metatarsal osteotomy (33 626 patients), DVT, pulmonary embolism and mortality rates were 0.01%, 0.02% and 0.04%, and for hindfoot fusions (7033 patients) the rates were 0.03%, 0.11% and 0.11%, respectively. The rate of pulmonary embolism in 1633 total ankle replacement patients was 0.06%, and there were no recorded DVTs and no deaths. Statistical analysis could only identify risk factors for venous thromboembolic events of increasing age and multiple comorbidities following fracture surgery.

Venous thromboembolism following foot and ankle surgery is extremely rare, but this subset of fracture patients is at a higher risk. However, there is no evidence that thromboprophylaxis reduces this risk, and these national data suggest that prophylaxis is not required in most of these patients.

The aim of total hip replacement is to relieve pain and restore function in patients with arthritic hips. The majority of standard implants come with a variety of offset sizes based on anthropological data from cadaveric and radiological studies. The placement of these components depend on a number of factors including soft tissue tension and hip stability at the time of hip implantation. The depth of placement of femoral component is solely under the surgeon’s control and can be influenced by the presence or absence of a component collar and the level of the neck resection itself. Inaccuracies in depth of femoral component placement will lead to length inequality which themselves can cause patient dissatisfaction and complications. In order to accurately place the femoral component a sound understanding of proximal femoral geometry is important. An often used landmark in replacement surgery is the tip of greater trochanter which is said to be at the level of the centre of the femoral head. This study is designed to assess the accuracy of this statement in a population of patients presenting for total hip replacement surgery at Nottingham City Hospital.

Pre-operative and post-operative radiographs of the replaced and contralateral hips were obtained and measured. A line perpendicular to the axis of the shaft of the femur touching the tip of the trochanter was used as a reference for depth of placement of measurement. The centre of the femoral head was estimated using concentric circles and marked. The vertical distance between the centre of the femoral head and the reference line was measured; the distance was recorded with reference to the tip of trochanter. Similar measurements were made post-operatively to assess the accuracy of femoral component placement.

Pre-operatively the centre of head was below the tip of trochanter in 85% of patients. The mean distance was 10mmbelow the tip of trochanter, with a range of 6mm above to 24mm below. In only 15% cases was the centre of head at or above the tip of trochanter.

By contrast post-operatively 55% patients had a femoral head centre at or above the level of tip of trochanter. This, therefore, represents a significant degree of lengthening in all patients where the tip of trochanter was used as a reference point for femoral component placement.

We investigated the incidence of cephalosporin-resistant bacteria in infected hip arthroplasties. Of 740 patients having hip replacement or related procedures performed over three years, 30 had positive bacteriological cultures from tissue removed at the time of surgery. In 18 of the 30 cultures Staphylococcus epidermidis was grown and 12 of these were methicillin-resistant. A prospective study of skin swabs taken from 100 consecutive patients at the time of admission for THR showed methicillin-resistant Staphylococcus epidermidis in 25. This cephalosporin-resistant organism was shown to be the commonest proven cause of infection, and its presence as a skin commensal raises important questions about current antibiotic prophylaxis for joint replacement.