Septic arthritis in Iceland 1990–2002: increasing incidence due to iatrogenic infections

OBJECTIVES To assess the impact of increased number of diagnostic and therapeutic joint procedures on the incidence and type of septic arthritis (SA). METHODS All cases of SA in Iceland from 1990-2002 were identified by thorough review of the available medical information. The results of synovial fluid cultures from every microbiology department in Iceland were checked and positive culture results reviewed, as well as patient charts with a discharge diagnosis of septic arthritis (International Statistical Classification of Diseases and Related Health Problems (ICD) code M009). RESULTS A total of 253 cases of SA (69 children and 184 adults) were diagnosed in Iceland in 1990-2002, giving an average incidence of 7.1 cases/100,000 inhabitants. The incidence of SA increased from 4.2 cases/100,000 in 1990 to 11.0 cases/100,000 in 2002. This rise in SA was primarily observed in adults where the incidence rose by 0.61 cases/100,000 per year (p<0.001). SA was iatrogenic in 41.8% of adults and the number of iatrogenic infections increased from 2.8 cases/year in 1990-1994 to 9.0 cases/year in 1998-2002 (p<0.01). The annual number of arthroscopies increased from 430 in 1990-1994 to 2303 in 1998-2002 (p<0.001) and there was a correlation between the total usage of intra-articular drugs in Iceland and the incidence of SA (p<0.01). The frequency of post-arthroscopy SA was 0.14% and post-arthrocentesis SA 0.037%. CONCLUSIONS The incidence of SA has increased in recent years due to an increased number of arthroscopies and joint injections. Although the frequency of SA per procedure has not changed, these results emphasise the importance of sterile technique and firm indications for joint procedures.