The International Consensus Meeting on Musculoskeletal Infection (ICM, Philadelphia 2018) recommended histology as one of the diagnostic tests although this is not routinely used in a number of UK hospitals. This study aims to explore the role of histology in the diagnosis of infection and whether it is of practical use in those cases where the microbiology samples are either diagnostically unclear or do not correspond to the pre-operative diagnosis or the clinical picture. We identified 85 patients who underwent revision knee arthroplasty for either septic or aseptic loosening and for whom both microbiology and histology samples were taken. The procedures were performed by the senior experienced surgeons specialised in revision knee arthroplasty in two centres from Liverpool. Each patient had a minimum of five tissue samples taken, using separate knife and forceps and each sample was divided in half and sent for microbiology and histology in different containers. Fifty-four patients (63.5%) underwent a single-staged revision; ten patients (11.8%) underwent the 1st stage of a two staged revision; eleven patients (12.9%) underwent the 2nd stage of a two staged revision; one patient (1.2%) underwent an additional revision stage; three patients (3.5%) were treated with a DAIR; three patients (3.5%) had a 2-in-1 revision; two patients (2.4%) had a debridement and polyethylene exchange; and one patient (1.2%) had an arthroscopy biopsy of knee replacement. The cost to process five microbiology samples for each patient was £122.45 on average and for the five histology samples was £130.Aims
Patients and Methods
Implant choice was changed from cemented Thompson to Exeter Trauma Stem (ETS) for treatment of displaced intra-capsular neck of femur fractures in University Hospital Aintree, Liverpool, United Kingdom (a major trauma center), following the NICE guidelines that advised about the use of a proven femoral stem design rather than Austin Moore or Thompson stems for hemiarthroplasties. The aim of our study was to compare the results of Thompson versus ETS hemiarthroplasty in Aintree. We initially compared 100 Thompson hemiarthroplasties that were performed before the start of ETS use, with 100 ETS hemiarthroplasties. There was no statistically significant difference between the two groups in terms of patients' demographics (age, sex and ASA grade), intra-operative difficulties/complications, post op medical complications, blood transfusion, in-patient stay and dislocations. The operative time was statistically significantly longer in the ETS group (p= .0067). Worryingly, the 30 days mortality in ETS group was more than three times higher in ETS group (5 in Thompson group versus 16 in ETS group. P= .011). To corroborate our above findings we studied 100 more consecutive patients that had ETS hemiarthroplasty. The results of this group showed 30 day mortality of 8 percent. However the operative time was again significantly longer (p= .003) and there was 18 percent conversion to bipolar hemiarthropalsty. Moreover there was statistically significant increased rate of deep infection (7%, p = .03) and blood transfusion (27%, p = .007). This we feel may be due to longer and more surgically demanding operative technique including pressurised cementation in some patients with significant medical comorbidities. Our results raise the question whether ETS hemiarthoplasty implant is a good implant choice for neck of femur fracture patients. Randomised control trials are needed to prove that ETS implant is any better than Thompson hemiarthroplasty implants in this group of patients.
