Reducing PJIs: The Myth of Laminar Flow

    Dr. John Charnley, the father of total hip arthroplasty (THA), was a big proponent of using body exhaust suits and laminar flow to reduce the incidence of periprosthetic joint infections (PJIs) in his patients.

    Too bad he got it so wrong about laminar flow.

    At ICJR’s Winter Hip & Knee Course, Jeremy M. Gililland MD, from the University of Utah in Salt Lake City, addressed the evidence for intraoperative strategies to reduce PJIs as part of the series of lectures on urban legends in total joint arthroplasty.

    RELATED: Urban Legends versus Evidence-Based Medicine in Total Joint Arthroplasty

    The urban legend about laminar flow started with Dr. Charnley. When he began performing THA in 1959, the rate of PJIs was approximately 10%. In the following decade, he lowered the infection rate to approximately 1%, ascribing the majority of this decrease to his use of laminar flow and body exhaust suits.

    In 1987, a multicenter study evaluated Dr. Charnley’s conclusion, randomizing 8000 patients to laminar flow versus standard air and body exhaust suit versus no suit to compare the effects of the interventions on the rate of PJI. [1] The use of prophylactic antibiotics was controversial at the time: Dr. Charnley felt that antibiotics were not indicated and that by avoiding them, surgeons would be acting as good antibiotic stewards.

    The study authors found that laminar flow decreased PJIs by 50% and that the use of body exhaust suits reduced the infection rate another 50%. The study also showed that antibiotics had a great impact on the infection rate, with the combination of antibiotics and body exhaust suits further reducing the rate of PJIs. However, the infection rate for the combination of laminar flow and antibiotics was about the same as it was for antibiotics alone. In other words, the addition of laminar flow did not improve the infection rate in patients who had received prophylactic antibiotics.

    RELATED: Register for the 11th Annual Winter Hip & Knee Course

    In the mid-2000s, several studies based on registry data painted a very different picture of the effects of laminar flow on the rate of PJIs in total hip and total knee arthroplasty patients. [2-4] One study of data from the German National Infection Surveillance System (2008) and 2 studies of data from the New Zealand Registry data (2011 and 2016) showed increased surgical site infection and increased revision for PJI in cases in which laminar flow was used. [2-4]

    Dr. Gililland said that with these studies, the laminar flow debate has been put to rest. But he noted that surgeons may still have 1 question: Why doesn’t laminar flow work? Fortunately, he has an answer. Dr. Gililland explained that laminar airflow in the operating room is disrupted by objects and people in the room, including the operating lights, the surgical equipment, and the operating room staff, which causes eddies and swirls in the airflow in the area around the patient. This, in turn, can bring infectious agents into the operative field – exactly the opposite of what laminar flow is intended to do.

    Click the image above to watch the presentation by Dr. Gililland, who also discusses skin prep, draping, antibiotic cement, and wound irrigation solutions.


    Dr. Gililland has no disclosures relevant to this presentation.


    1. Lidwell OM, Elson RA, Lowbury EJ, et al. Ultraclean air and antibiotics for prevention of postoperative infection. A multicenter study. Acta Ortop Scan, 1987; 58(1):4-13
    2. Brandt C, Hott U, Sohr D, Daschner F, Gastmeier P, Rüden H. Operating room ventilation with laminar airflow shows no protective effect on the surgical site infection rate in orthopedic and abdominal surgery. Ann Surg.2008 Nov;248(5):695-700
    3. Hooper GJ, Rothwell AG, Frampton C, Wyatt MC. Does the use of laminar flow and space suits reduce early deep infection after total hip and knee replacement? The ten-year results of the New Zealand Joint Registry. J Bone Joint Surg Br 2011; 93(1): 85-90
    4. Tayton ER, Frampton C, Hooper GJ, Young SW. The impact of patient and surgical factors on the rate of infection after primary total knee arthroplasty: an analysis of 64,566 joints from the New Zealand Joint Registry. Bone Joint J. 2016 Mar;98-B(3):334-40.