Is this shoulder infected?

 A 61 year old lady with systemic lupus erythematosus controlled on hydroxychloroquine on peritoneal dialysis for chronic renal failure and allergic (rash) to Keflex, Penicillins, and Doxcyline presents with a painful and stiff right shoulder hemiarthroplasty. 

Her preoperative CBC was normal. There was no clinical suggestion of infection.

After discussion of the alternatives, she elected to have a reverse total shoulder arthroplasty. 

At surgery, aspiration of her joint revealed cloudy fluid with 4+ neutrophils. A biopsy of her collar membrane was reported as below 

Her single stage revision was carried out with concern about the possibility of infection. Betadine lavage and topical antibiotics were used.

Our Infectious Disease consult recommended cefpodoxime PO, which she has tolerated well. Six deep cultures were obtained, only one of which had bacterial growth (one colony of Bacillus species, not anthracis from 1 of 5 media).

The reader may wish to decide if the MSIS criteria for periprosthetic infection are helpful in the management of this case.

In any event the plan is to continue oral antibiotics for 6 months, being thankful that she has had no adverse reactions.

Comment: A practical approach is to (1) consider treating obvious infections (e.g. erythema, swelling, drainage, elevated serum markers, positive aspirate for virulent organisms, failed single stage) with a two stage revision unless the patient's condition prohibits and (2) treating all other revisions as if they might be infected (taking five deep cultures, thorough debridement, thorough lavage, single stage revision and oral antibiotics at least until the culture results are finalized at three weeks).

Contact: shoulderarthritis@uw.edu

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