Saturday, February 11, 2017

Infection of shoulder joint replacement

Surgical management of periprosthetic shoulder infections

These authors reviewed patients having either a 1-stage partial component exchange (15 cases), a 1-stage complete removal and reimplantation (45 cases) or a 2-stage revision arthroplasty (19 cases) for periprosthetic joint infection.

Recurrence of infection was determined  by postoperative clinical signs of infection (elevated laboratory studies, drainage, swelling, and erythema) or by a reoperation for infection after the index (1-stage or 2-stage) procedure at a minimum of 1 year after the procedure.

At a minimum of 1 year followup, re-operation for infection was performed in
4 of 15 partial component exchanges,
2 of 45 complete single stage exchanges
4 of 19 2-stage procedures 

Reinfection rates were highest in patients whose cultures grew Staphylococcus aureus or coagulase negative Staphylococcus species and in those treated with a partial component exchange.

Comment: It is of interest that 
(1) less than half of the cases had evidence of what we refer to as an 'obvious' infection (local or systemic signs, abnormal laboratory tests).

(2) of the 29 planned 2-stage procedures, 10 elected not to undergo the second stage
(3) 21 (24%) of these shoulders diagnosed as having infection had negative cultures at surgery, but had positive pathology for acute inflammation. 
(4)  Propionibacterium acnes was the most commonly isolated organism (26 of 89 [29%]) and coagulase-negative Staphylococcus  species (CoNS) was  was the second most common (24 of 89 [27%]
(5) the criteria for determining recurrence of infection may not be sensitive to a 'stealth' presentation as discussed in the posts below.

Periprosthetic shoulder infections: single or two-stage revision?
Shoulder arthroplasty infections - how should they be treated?

While obvious periprosthetic infections are obvious, the evaluation and management of 'stealth' infections is challenging. Our approach to most cases of failed shoulder arthroplasty is to perform a single stage exchange to a stemmed hemiarthoplasty fixed with Vancomycin-soaked allograft, recognizing that the presence of bacteria in the joint cannot be reliably determined at the time of surgery.