How do revised shoulders that are culture positive for Propionibacterium differ from those that are not?
BACKGROUND
Many shoulder arthroplasties revised for pain, stiffness, or component loosening are culture positive for Propionibacterium. The culture results are unknown until days or weeks after surgery, too late to inform intraoperative surgical decisions and immediate postsurgical antibiotic treatment. The objective of this study was to identify preoperative and intraoperative characteristics that may alert surgeons to an increased likelihood of positive cultures.


METHODS
We analyzed the records of 132 shoulders that underwent surgical revision of a shoulder arthroplasty, 66 of which became culture positive for Propionibacterium and 66 did not.


RESULTS
Propionibacterium-positive and Propionibacterium-negative shoulders were similar with respect to many characteristics; however, Propionibacterium-negative shoulders were revised sooner after the index procedure and were significantly more likely to be female, to have sustained a fall, to have instability, and to have rotator cuff deficiency. Intraoperatively, Propionibacterium-positive shoulders demonstrated more glenoid erosions, glenoid osteolysis, glenoid loosening, and a higher incidence of a soft tissue membrane between the humeral component and humeral endosteum. Shoulders culture positive for Propionibacterium were more likely to be culture positive for another bacteria.


CONCLUSIONS
Although Propionibacterium-positive and Propionibacterium-negative shoulders have many similarities, factors such as male gender, delayed presentation, glenoid osteolysis and loosening, humeral membrane, and the absence of instability or cuff failure should arouse suspicion of Propionibacterium and suggest the need for deep cultures and consideration of aggressive surgical and medical treatment.
Department of Orthopaedics and Sports Medicine, University of Washington, Clyde Hill, WA, USA.
Clifford
C
Hou
Department of Orthopaedics and Sports Medicine, University of Washington, Clyde Hill, WA, USA.
Akash
A
Gupta
Department of Orthopaedics and Sports Medicine, University of Washington, Clyde Hill, WA, USA.
Michael
M
Chen
Department of Orthopaedics and Sports Medicine, University of Washington, Clyde Hill, WA, USA. Electronic address: matsen@uw.edu.
Frederick A
FA
Matsen
D000193:Actinomycetales Infections / Q000382:microbiology* / Q000601:surgery; D000368:Aged; D019643:Arthroplasty, Replacement; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000382:microbiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011424:Propionibacterium / Q000302:isolation & purification*; D016459:Prosthesis-Related Infections / Q000382:microbiology* / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D012785:Shoulder Joint / Q000382:microbiology* / Q000601:surgery
Propionibacterium; culture positive; shoulder arthroplasty