title: Quantification Analysis of the Intraoperative Bacterial Contamination Rate and Level in Osteochondral Autografts.
abstract: BACKGROUND
  Inadvertent contamination of osteochondral (OC) autografts during harvesting and preparation can lead to significant complications and can cause the operating team to weigh the infection risk after reimplantation against discarding the OC fragment. The most commonly reported contamination mechanism is the accidental dropping of an OC fragment; however, associated contamination levels remain unclear. The rate and level of contamination during standard harvesting and preparation are also unknown.
  
  
  OBJECTIVE
  To quantitatively evaluate the rate and level of bacterial contamination of OC autografts during harvesting and preparation compared with those of accidently dropped autografts.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Under sterile conditions, 138 fresh OC specimens were harvested and retrieved from 23 primary total knee arthroplasties (TKAs). Six OC fragments were retrieved from each TKA: 3 were used as controls, and 3 were dropped onto the operating room floor. Each specimen was incubated to allow for aerobic and anaerobic growth, and the number of colony-forming units (CFUs) per gram was calculated.
  
  
  RESULTS
  Contamination rates (positive cultures) for the control and dropped groups were 29% (n = 20/69) and 42% (n = 29/69), respectively. The difference in the contamination rate between groups was not statistically significant (P = .109). The most common organisms identified were Staphylococcus aureus (40%) in the control group and Staphylococcus epidermidis (24.1%) and Bacillus species (20.7%) in the dropped group. The contamination level (CFUs/g) for both groups was low. The median (range) CFUs/g among the contaminated specimens in the dropped and control groups were 27 (1-120) and 3 (1-15), respectively (P < .0001).
  
  
  CONCLUSIONS
  A relatively high rate of OC autograft contamination can be expected during harvesting and preparation (29%) or after accidentally dropping a specimen (42%). Although the types of organisms isolated differed between specimens contaminated during harvesting and preparation and dropped specimens, the quantification of the autograft contamination level revealed a very low CFUs/g in both cases.
  
  
  CONCLUSIONS
  The intraoperative autograft contamination level is very low. Hence, in cases of grafts with a known contamination incident, saving and reimplanting them after proper decontamination is recommended over discarding them or using an allograft.
authors.affiliation: Orthopaedic Department, King Saud University Medical City, College of Medicine, King Saud University, Riyadh, Saudi Arabia dr_abdulaziz@yahoo.com.
authors.forename: Abdulaziz Z
authors.initials: AZ
authors.lastname: Alomar
authors.affiliation: Department of Pathology and Laboratory Medicine/Microbiology Unit, King Saud University Medical City, College of Medicine, King Saud University. Riyadh, Saudi Arabia.
authors.forename: Ali Mohammed
authors.initials: AM
authors.lastname: Somily
authors.affiliation: Orthopaedic Department, McGill University, Montreal, Quebec, Canada.
authors.forename: Thamer M
authors.initials: TM
authors.lastname: Alraiyes
authors.affiliation: Orthopaedic Department, King Saud University Medical City, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Ahmad S
authors.initials: AS
authors.lastname: Bin Nasser
authors.affiliation: Orthopaedic Department, King Saud University Medical City, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Fawzi F
authors.initials: FF
authors.lastname: Aljassir
mesh_terms: D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D064592:Autografts / Q000382:microbiology* / Q000601:surgery; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000382:microbiology*; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods; D013210:Staphylococcus / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013710:Tendons / Q000382:microbiology*; D014182:Transplantation, Autologous
keywords: autograft; bone graft; osteoarticular; osteochondral