title: Clinical Analysis of Propionibacterium acnes Infection After Total Knee Arthroplasty.
abstract: Propionibacterium acnes is a common cause of upper extremity arthroplasty infection and usually presents in an indolent subacute fashion. It is not well described how total knee arthroplasty (TKA) patients infected with P acnes present.
  
  
  
  We retrospectively compared patients undergoing revision TKA for infection from P acnes and methicillin-sensitive Staphylococcal aureus (MSSA) in our institutional infection database. Patients were classified as having a periprosthetic joint infection based on the Musculoskeletal Infection Society criteria and were excluded if they had a polymicrobial culture. Patient demographics, preoperative laboratory values, microbiology data, and synovial fluid white blood cell (WBC) counts were analyzed.
  
  
  
  Sixteen patients with a P acnes and 30 with an MSSA TKA periprosthetic joint infection were identified. Median erythrocyte sedimentation rate was significantly higher in the MSSA group compared to the P acnes group (56.0 mm/h; interquartile range [IQR], 44.3-72.9 vs 23.0 mm/h; IQR, 18.5-52.0; respectively, P = .03) as were C-reactive protein levels (5.9 mg/dL; IQR, 3.7-26.9 vs 2.0 mg/dL; IQR, 0.5-14.0; respectively, P = .04). WBC count, synovial fluid WBC, and percentage of synovial polymorphonuclear cells were similar between groups. Mean time to culture was 8.3 ± 2.0 days in the P acnes group and 1.8 ± 0.8 days in the MSSA group.
  
  
  
  P acnes TKA infections are associated with more acute inflammatory symptoms than typically appreciated, and long hold anaerobic cultures up to 14 days are necessary to accurately identify this organism as the causative agent of TKA periprosthetic infection.
authors.affiliation: Department of Orthopedics, Hospital for Special Surgery, New York, New York.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Nodzo
authors.affiliation: Department of Orthopedics, Hospital for Special Surgery, New York, New York.
authors.forename: Geoffrey H
authors.initials: GH
authors.lastname: Westrich
authors.affiliation: Department of Infectious Disease, Hospital for Special Surgery, New York, New York.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Henry
authors.affiliation: Department of Infectious Disease, Hospital for Special Surgery, New York, New York.
authors.forename: Andy O
authors.initials: AO
authors.lastname: Miller
mesh_terms: D000328:Adult; D000368:Aged; D001170:Arthritis, Infectious / Q000175:diagnosis* / Q000382:microbiology; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D011425:Propionibacterium acnes; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000382:microbiology; D012189:Retrospective Studies
chemical_list: D002097:C-Reactive Protein
keywords: Propionibacterium acnes; clinical presentation; complications; periprosthetic infection; total knee arthroplasty