Background

Frequency of primary total hip (THA) and total knee (TKA) arthroplasty procedures is increasing, with a subsequent rise in revision procedures. This study aims to describe timing and excess surgical mortality associated with revision THA and TKA compared to those on the waiting list.

Background

Over 96% of primary total hip replacements (THR) recorded in the National Joint Registry (NJR) are performed through a posterior or lateral surgical approach. There is no high quality evidence available to support the use of one approach over the other in primary THR and even less evidence when the outcome of revision THR is considered.

Aim

Compare clinical outcomes following staged revision arthroplasty for periprosthetic joint infection (PJI) secondary to either multidrug resistant (MDR) bacteria or non-MDR (NMDR) bacteria.

Aim

Periprosthetic joint infections (PJI) are rare and require complex multi-disciplinary management. Successful single and two-stage revision procedures have been described. We describe the clinical features of this rare diagnosis from a single institution.

We would like to present this service evaluation of Taylor Spatial Frame use within a busy limb reconstruction unit.

We present a cohort of 60 patients representing a year of work from January 2011 to January 2012 with a breakdown of coding data. Included are details of operative episodes, length of stay, outpatient follow up including software programming episodes, strut changes and general frame care from our specialist nurses. We have produced a comparison of cost to HRG coding tarifs with an audit of coding errors and cost implications of these corrections. Also included is a breakdown of comparison data from patients undergoing frame assisted deformity correction and internal fixation, Computer Hexapod Assisted Orthopaedic Surgery.

Exact and careful coding of these procedures is required considering their relatively high cost.

Introduction

Post-traumatic arthritis is the commonest cause of arthritis of the ankle. Development of arthritis is dependent on the restoration of pre-injury anatomy. To assess the effect of grade of lead surgeon on the accuracy of surgical reduction, we performed a retrospective radiographic analysis of all ankle fractures undergoing open reduction and internal fixation, in a single institution.

Orthopaedic cobalt chromium particles and ions can induce indirect DNA damage and chromosome aberrations in human cells on the other side of a cellular barrier in tissue culture. This occurs by intercellular signalling across the barrier. We now show that the threshold for this effect depends on the metal form and the particle composition.

Ionic cobalt and chromium induced single strand breaks at concentrations equivalent to those found in the blood of patients with well functioning metal on metal hip prostheses. However, they only caused double strand breaks if the chromium was present as chromium (VI), and did not induce chromosome aberrations. Nanoparticles of cobalt chromium alloy caused DNA double strand breaks and chromosome aberrations, of which the majority were tetraploidy. Ceramic nanoparticles induced only single strand breaks and/or alkaline labile sites when indirectly exposed to human fibroblasts.

The assessment of reproductive risk from maternal exposure to biomaterials, especially those liberated by orthopaedic implants, is not yet possible with epidemiology. Whilst the barrier model used here differs from the in vivo situation in several respects, it may be useful as a framework to evaluate biomaterial induced damage across physiological barriers.

Total knee arthroplasty (TKA) remains a safe and effective intervention for the treatment of arthritis of the knee. It does, however, carry risks including death. Studies have compared the incidence of death following TKA to standardised mortality ratios of matched populations. This often suggests that TKA is protective to health in the immediate post operative phase, attributed to the lower incidence of co-morbidities in patients undergoing surgery.

In an attempt to remove this “well patient effect”, we compared the incidence of death in the first 30 and 90 days following primary TKA to that of a comparable population added to a waiting list for the same procedure.

All primary TKAs undertaken, and all patients added to a waiting list for the same procedure, in a single unit between 2000 and 2007 were recorded. Death rates at 30 and 90 days were compared in each group.

The 30 and 90 day mortality following primary TKA were 0.295% and 0.565% respectively, compared to a 30 and 90 day mortality of 0.055% and 0.316% seen in a population of patients awaiting operation. When stratified for age, surgery conferred an excess surgical mortality in all age groups over the age of 60. Factors associated with an increased mortality following operation include male gender and increasing age.

Previous studies have suggested that TKA is associated with a decreased risk of death. This study demonstrates an increased risk of death associated with surgery in comparison to a similar population deemed fit enough to undergo operation. Primary TKA carries an excess surgical mortality of 0.24% at 30 days and 0.25% at 90 days, a 5.36 and 1.79 times greater risk of death when compared to patients awaiting the same procedure.

This information will greatly assist orthopaedic surgeons when counselling patients as to the risks of surgery.

Total knee arthroplasty represents one of the greatest advances in modern orthopaedic surgery and remains one of the safest and most effective interventions for the treatment of crippling arthritis of the knee. It does, however, carry significant risk including death. Conventional studies have compared the incidence of death following knee arthroplasty to standardised mortality ratios of age and sex matched populations. This often raises aberrant results suggesting that knee arthroplasty is protective to health in the immediate post operative phase, attributed to the observation that patients undergoing surgery suffer fewer co morbidities than the population in general.

In an attempt to remove this “well patient effect”, we compared the incidence of death in the first 30 and 90 days following primary total knee arthroplasty to the incidence of death in a comparable population added to a waiting list for the same procedure.

All primary total knee arthroplasties undertaken, and all patients added to a waiting list for the same procedure, in a single unit between 2000 and 2007 were recorded. Death rates at 30 and 90 days of those on the waiting list were compared to death rates after surgery.

The 30 and 90 day mortality following primary total knee arthroplasty were 0.295% and 0.565% respectively. This compares to a 30 and 90 day mortality of 0.055% and 0.316% seen in a population of patients awaiting operation. When stratified for age, surgery conferred an excess surgical mortality in all age groups over the age of 60. Factors associated with an increased mortality following operation include male gender and increasing age.

Previous studies, where incidence of death is compared to standardised mortality ratios, have erroneously suggested that arthroplasty is associated with a decreased risk of death. This study demonstrates an increased risk of death associated with surgery in comparison to a similar population deemed fit enough to undergo operation. Primary total knee arthroplasty carries an excess surgical mortality of 0.24% at 30 days and 0.25% at 90 days, a 5.36 and 1.79 times greater risk of death respectively when compared to patients awaiting the same procedure.

This information will greatly assist orthopaedic surgeons when counselling patients as to the risks of surgery.

Introduction: Of all hip arthroplasties conducted annually, a proportion will subsequently require revision for aseptic loosening and periprosthetic osteolysis. Osteolysis may develop ‘silently’ and monitoring of patients is recommended. This should include x-rays as progressive changes in size of a lesion may indicate a potential failure. Area measurement of osteolysis has been achieved in a number of ways but with techniques that are not readily available in routine clinical practice. The aim of this study was to develop a method for routine assessment of hip arthroplasty to quantify osteolytic changes seen on x-ray, applicable by any health professional and with good inter-observer reliability.

Methods: A morphometric grid is superimposed on an object of interest and the number of test points that fall within a defined area counted. A specialized grid was developed and initial testing was conducted on twenty simulated osteolytic lesions. Subsequent testing was on thirty-five arthroplasty x-rays with evidence of osteolytic lesions. Four observers recorded the number of crosses seen over each lesion. The observers were representative of health professions and levels of experience involved in arthroplasty review.

Data was analysed for both inter-observer and test-retest reliability using the intra-class correlation coefficient and the Bland-Altman method (use of two methods provides a better estimation of accuracy).

Results: The results for intra-class correlation coefficients on both simulated and actual lesions were all excellent (range 0.90 to 0.98) as confirmed by visual representation using the Bland-Altman method.

Discussion: Regular follow-up of hip arthroplasty with x-ray ensures that changes are monitored even when symptoms are absent. We believe that this tool can improve the process through quantitative assessment of osteolytic lesions. The scientific development supports the reliability of the tool when used by a number of raters and the simplicity of application makes it a useful addition to an arthroplasty clinic.

Introduction: Venous thromboembolism is a major cause of morbidity and mortality in hospitalised patients and patients undergoing major orthopaedic surgery are at high risk from venous thromboembolism. Thromboprophylaxis, both mechanical and chemical, is commonly administrated to reduce fatality from thromboembolism after surgery. However, there is no convincing evidence in the literature demonstrating that routine chemothromboprophylaxis reduces death rates from pulmonary embolus. Furthermore, it is unclear from the literature which thromboprophylactic agent, if any, should be used.

Recent NICE guidelines have recommended that heparin should be routinely administered to patients under-going THR to prevent thromboembolism, although it is unclear from the existing evidence if heparin is the most effective. However, research has suggested that aspirin, which is a low cost prophylactic agent, is effective in preventing DVT and PE after orthopaedic surgery. The aim of this study was to determine the 90-day mortality rate after THR using aspirin as a prophylactic agent.

Patients and Methods: Between 2003–2006, 2,286 patients underwent primary THR and 372 patients underwent revision hip replacement (RHR). Routine chemothromboprophylaxis consisting of aspirin 75mg daily for 6 weeks. In addition all patients were treated with anti-thromboembolic stockings. 40mg of subcutaneous clexane, in lieu of aspirin, was given daily to all patients who had previously suffered from a pulmonary embolus or deep venous thrombosis. Patients who died within 90 days of surgery had their death certificates examined. Retrieval at 90 days with regard to death was 100%.

Results:

Primary THR

One patient (0.04%) died within 30 days of surgery and a further 3 (0.13%) died between day 30 and day 90, giving a total mortality at 90 days of 0.17% (4/2,286). One patient (0.04%) died from PE and the other 3 patients (0.13%) died from non-vascular causes.

Discussion: This study found that the 30-day mortality rate for primary THR and RHR was 0.08% and the 90-day mortality rate was 0.23%. In this study, there was only one death from PE and no deaths from arterial complications. Therefore, although NICE guidelines suggest the use of heparin, this study found that routine aspirin administration is beneficial in protecting against early death after THR because of both thromboembolism and adverse arterial events.

A research programme has been directed at the mechanism by which car occupants sustain ankle and hind-foot injuries. The severe injuries that are most associated with long term disability and high socio-economic cost have been investigated. Although seat belts and air bags have had a beneficial effect on injuries to most body regions including pelvic, femur and knee injuries, no protective effect has been demonstrated for below knee injuries. Only by understanding the mechanism of injuries to the leg below the knee will it be possible to design improved protection in the future.

Twenty three post mortem human surrogate (PMHS) limbs were impacted using a test set up that was developed to simulate the loading conditions seen in a frontal collision in 3 different positions – A, B & C. The impactor head (5cm x 10cm wide), was instrumented with an accelerometer and linear potentiometer. The impacting force was generated using a bungee-powered sled mounted on steel bearings. Three PMHS legs were tested In Position A (impactor head centred in line with the tibial axis), 9 PMHS legs were tested in Position B (impactor head centred on the anterior tibial margin) and 11 PMHS legs were tested in Position C (impactor head centred 2.5cm anterior to the anterior tibial margin). Active dorsiflexion was simulated through the Achilles tendon and prior to the application of Achilles tension a tibial pre-load (500 to1500N) was applied via a ‘jacking-plate’ applied to the proximal end of the tibia.

During impact testing, bone failure (fractures) occurred at impact loads of 5.7+/−1.9 kN (resultant tibial failure load 6.4+/−1.9 kN) and the following injuries were generated: 9 intra-articular calcaneal fractures; 1 talar neck and 2 talar body fractures; 3 intra-articular distal tibial (pilon) fractures; 2 malleolar fractures; 3 soft tissue injuries and in 3 cases there was no detectable injury. The impact test conditions were replicated with a Hybrid III leg in a first attempt at developing injury risk functions for the dummy.

This study has demonstrated the importance of preload through muscle tension in addition to the intrinsic properties of PMHS specimens in the generation of severe ankle and hindfoot injury.