The use of routine sampling for histological analysis during revision hip replacement has been standard practice in our unit for many years. It is used to identify the presence of inflammatory processes that may represent peri-prosthetic infection.

This study follows up on a smaller study in the same unit in 2019 where an initial 152 cases were scrutinised. In this follow up study we examined 1,361 consecutive patients over a 16-year period whom had undergone revision hip replacement in a tertiary orthopaedic centre for any reason excluding primary bone tumour or malignant metastasis. All patients had tissue sampling for histopathological analysis performed by consultant histopathologists with a specialist interest in musculoskeletal pathology. The presence of bacteria in greater than 50% of samples sent for microbiological analysis in each patient was used as the gold standard diagnostic comparator for infection. This was then compared with the histology report for each patient.

After excluding 219 patients with incomplete data and 1 sample rejection, 1,141 cases were examined. Microbiology confirmed infection in 132 cases (prevalence of infection 11.04%) and histopathology analysis suggested infection in 171 cases. Only 64 cases with confirmed infection in more than 50% of microbiology samples had concurrent diagnosis of infection on histological analysis (5.60% of total; PPV 51.20%). Furthermore, microbiology analysis confirmed infection in 62 cases where histological analysis failed to identify infection (5.43% of total; False negative rate 49.21%). Overall, histopathology analysis was seen to have a good specificity of 93.99% but poor sensitivity of 50.79%.

We believe that this is the largest series in the literature and is somewhat unique in that all histology analysis was performed by consultant histopathologists with specialist interest in musculoskeletal pathology. Based on the costs incurred by this additional investigation our experience does not support routine sampling for histological analysis in revision hip arthroplasty. This is a substantial paradigm shift from current practice among revision arthroplasty surgeons in the United Kingdom but would equate to a substantial cost saving.

The use of routine sampling for histological analysis during revision hip replacement has been standard practice in our unit for many years. It is used to assess for the presence of inflammatory processes that may represent peri-prosthetic infection.

Our study examines 152 consecutive patients who underwent revision hip replacement in our centre for all reasons, excluding malignant neoplasm or metastasis. We reviewed the cases from a prospectively collated database, comparing microbiology results with histology results. Both microscopic and macroscopic analysis by specialist musculoskeletal histopathologist was included in our study.

We found 17 (11.2%) patients had cultured bacteria from intra-operative samples. Eight patients (5.3%) had histological findings interpreted as infection. Only one patient who had macroscopic and microscopic histology findings suggestive of infection also had culture results that identified a pathogen. Furthermore, the macroscopic analyses by the histopathologist suggested infection in nine patients. Only one patient with positive culture in greater than 2 samples had histological features of infection.

Of the 4 patients who were found to have 3 or more samples where an organism was identified only one had histological features of infection. This represents 25% sensitivity when using histology to analyse samples for infection. Of the 8 patients who had both macroscopic and microscopic features of infection only 1 patients cultured bacteria in more than 3 samples (PPV 12.5%).

Our experience does not support the routine sampling for histology in revision hip replacement. We suggest it is only beneficial in cases where infection is suspected or where a multi-procedure, staged revision is performed and the surgeon is planning return to theatre for the final stage. This is a substantial paradigm shift from the current practice among revision arthroplasty surgeons in the United Kingdom but will equate to a substantial cost saving.