The gold standard treatment for late acute hematogenous (LAH) periprosthetic joint infection (PJI) is surgical debridement, antibiotics and implant retention (DAIR). However, this strategy is still controversial in the case of total knee arthroplasty (TKA) as some studies report a higher failure rate. The aim of the present study is to report the functional outcomes and cure rate of LAH PJI following TKA treated by means of DAIR at a long-term follow-up.
A consecutive prospective cohort consisting of 2,498 TKA procedures was followed for a minimum of 10 years (implanted between 2005 and 2009). The diagnosis of PJI and classification into LAH was done in accordance with the Zimmerli criteria (NEJM 2004). The primary outcome was the failure rate, defined as death before the end of antibiotic treatment, a further surgical intervention for treatment of infection was needed and life-long antibiotic treatment or chronic infection. The Knee Society Score (KSS) was used to evaluate clinical outcomes. Surgical management, antibiotic treatment, the source of infection (primary focus) and the microorganisms isolated were also assessed.
Among the 2,498 TKA procedures, 10 patients were diagnosed with acute hematogenous PJI during the study period (0.4%). All those 10 patients were operated by means of DAIR, which of course included the polyethylene exchange. They were performed by a knee surgeon and/or PJI surgeon. The failure rate was 0% at the 8.5 years (SD, 2.4) follow-up mark. The elapsed time between primary total knee replacement surgery and the DAIR intervention was 4.7 years (SD, 3.6). DAIR was performed at 2.75 days (SD 1.8) of the onset of symptoms. The most common infecting organism was S. aureus (30%) and E. coli (30%). There were 2 infections caused by coagulase-negative staphylococci and 2 culture-negative PJI. All culture-positive PJI microorganisms were susceptible to antibiofilm antibiotics. The source of infection was identified in only 3 cases. The mean duration of antibiotic treatment was 11.4 weeks (SD 1.9). The postoperative clinical outcomes were excellent, with a mean KSS of 84.1 points (SD, 14.6).
Although the literature suggests that TKA DAIR for acute hematogenous periprosthetic joint infection is associated with high rates of failure, the results presented here suggest a high cure rate with good functional outcomes. Some explanations for this disparity in results may be the correct diagnosis of LHA, not misdiagnosing acute chronic PJI, and a thorough debridement by surgeons specialized in PJI.