Abstract
Aim
Prosthetic joint infections (PJI) are devastating complications after hip arthroplasty and infection rates varies internationally between 0.76% to 1.24%. Hemi-arthroplasty (HA) is the gold standard treatment for dislocated femoral neck fractures. Recently, total hip arthroplasty (THA) has been suggested to generate even better outcomes. However, little is known about PJIs after hip fractures. The purpose of this study was to investigate PJIs after femoral neck fracture in a population-based sample.
Methods
Clinical databases were harvested for all THA or HA procedures done for the treatment of femoral neck fractures at our hospital district (HUS) of 1.6 million inhabitants. Altogether, 3693 arthroplasty procedures for hip fractures were performed between 2011 to 2015. The original patient records of each case were reviewed. Complication(s) leading to readmission(s), the microbe(s), and the treatment protocol of each infection was recorded until the closing date (31.12.2016). The definition of PJI according to Musculosceletal Infection Society modified at the International Consensus meeting was used.
Results
We detected 111 infections (10 THAs;101 HAs):42 superficial infections (1.1%) and 69 PJIs (1.9%). The PJI rate after THA was 3.7% (8/219) and 1.8% after HA (61/3474) (p=0.04;OR 2.12, 95%CI 1.00–4.49). Most PJIs in THA group (6/8) were treated by debridement, antimicrobials, and implant retention (DAIR) and two by 2-stage exchange. In the HA group the DAIR was the first surgical treatment for 51 PJIs (84%). Other treatment options used were girdlestone (n=3), one-stage exchange (n=2), lavation (n=2), and conservative treatment (n=3). The bacteria cultured at THA group were: Staphylococcus epidermidis (n=4), Staphylococcus aureus (n=3), Streptococcus agalactiae (n=2), and Staphylococcus haemolyticus and at the HA group Staphylococcus aureus (n=25, including 1 MRSA), Staphylococcus epidermidis (n=11), other coagulase negative staphylococci (n=7), Pseudomonas aeruginosa (n=6), Enterococcus faecalis (n=6), Escherichia coli (n=2), and streptococci (n=2). Multiple bacteria were cultured from seven PJIs. The causative microbe was unknown in five PJIs.
Conclusion
THA patients had higher rate of PJIs compared to HA, however, the small sample size of the THA group may limit the statistical power of this study. The PJIs after hip fractures were usually treated by DAIR, which is also main PJI treatment after elective THAs. The overall PJI rate was higher among hip fracture than after elective THAs in the literature. The existing trend of treating more dislocated hip fractures with THA may thus lead to increased rated of PJIs in the future.
