Microorganisms responsible for periprosthetic knee infections in England and Wales

This study aimed to delineate epidemiology of infecting microorganism genus in first-time revision knee arthroplasty for indication of periprosthetic joint infection in England and Wales using linked registry data.

From the National Joint Registry database for England and Wales, a consecutive series of primary knee arthroplasties performed between April 2003 and January 2014 that went on to have a revision for periprosthetic infection were identified (n = 2810). Each case was then linked to microbiology data held by Public Health England in order to identify infecting microorganism at time of revision surgery established from intra-operative cultures. Following data linkage, 403 culture results at time of revision surgery were identified in a group of 331 patients. The demographic characteristics of five microorganism groups were compared: pure staphylococcus (single genus), pure streptococcus (single genus), other gram-positive infections (single genus), gram-negative infections (single genus) and mixed genus infections.

Staphylococcus species was the most common organism genus isolated after revision of a primary implant for infection and present in 72 % of cases overall (71.3 % of patients with a single-genus infection and 76.8 % of patients with mixed genus infection). A pure staphylococcal infection was present in 59 % of all cases. A single-genus infection was responsible for infection in 83.1 % of cases, and mixed genera were responsible in 16.9 % of cases. A significant difference was observed for mean age at primary procedure in the cohort of patients where there was an isolated pure streptococcal infection (73.2 years) when compared to gram-negative infections (65.0 years). No other significant differences were observed between microorganism groups in terms of BMI, gender, ASA grade, indication for primary procedure and primary implant characteristics.

Staphylococci were the most commonly isolated organism species responsible for periprosthetic infection of primary arthroplasty in England and Wales. This information can be used by surgeons to benchmark and audit their own practice against national, publicly available data. Furthermore, this study has shown that even when using the largest national databases available, there is a substantial volume of missing data. Antimicrobial resistance represents a growing clinical problem with significant health and social costs. In order to counteract this threat, this study would advocate the consolidation of national microbial data in order to guide effective strategies towards targeting and combating the threat of antimicrobial resistance.

IV.