Posts on this shoulder blog have provided evidence that:(1) Cutibacterium - commensal bacteria commonly found in the dermis of normal skin - are the most common organism causing periprosthetic infections (PJI) of the shoulder. By contrast infections of total hip and total knee replacements are usually caused by other types of bacteria.
(2) Cutibacterium are often isolated from specimens obtained at revision for a failed arthroplasty, even in the absence of a preoperative suspicion of PJI.
(3) The risk of Cutibacterium PJI is increased in young, healthy male patients having had prior surgery, patients having high loads of Cutibacterium on their skin surface, in patients taking supplemental testosterone, and those with recent steroid injections of the shoulder.
(4) These organisms are released into the surgical wound from the dermis when the skin incision is made
(5) Cutibacterium cannot be eliminated from the dermis by presurgical skin treatment, preoperative antibiotics, or surgical skin preparation
(6) While Betadine or antibiotic irrigation solutions and in-wound antibiotics may be helpful in reducing the load of bacteria in the surgical field, the evidence that they reduce the rate of infection is not robust.
(7) Cutibacterium tend to form an adherent biofilm, especially on titanium-alloy stems; thus, complete prosthesis exchange after debridement may be necessary to resolve an infection.
(8) Some infections are obvious (redness, swelling, tenderness, elevated serum and synovial fluid inflammatory markers); however, Cutibacterium infections typically have a stealth presentation with the otherwise unexplained onset of pain and stiffness months after the index arthroplasty.
(9) Joint fluid aspiration can be helpful if the fluid is culture positive, but negative cultures do not rule out infection.
(10) At the time of revision surgery at least 5 deep specimens (tissue / explants) need to be submitted for culture in order to optimize the identification of a PJI.
(11) Specimens taken to detect Cutibacterium must be cultured on aerobic and anaerobic media and observed for at least two weeks.
(12) Because the results of these cultures are not finalized for weeks after surgery, patients are placed on antibiotics after revision surgery until the culture results are known.
(13) In rare cases if an infection is diagnosed soon after the primary arthroplasty, consideration can be given to debridement and irrigation with retention of the implants and antibiotic therapy after surgery. This may be an option for patients with cemented implants and patients who may not be sufficiently healthy for a major revision.
(14) In cases with a stealth presentation of pain and stiffness after a "honeymoon" period of routine post-arthroplasty recovery, consideration is often given to a single stage exchange with vigorous debridement and postoperative antibiotics until the culture results are finalized.
(15) In cases of obvious infection (redness, tenderness, swelling, drainage, elevated inflammatory markers, or wound drainage) and in cases of failed single stage revision, a two-stage revision can be considered (stage 1: implant removal, cultures, irrigation, implantation of an antibiotic-containing spacer, post operative antibiotics; when evidence of infection no longer present=>stage 2: repeat debridement, cultures, definitive implant insertion, and postoperative antibiotics).
(16) Two stage revisions are more costly and complication-prone than single stage revisions
(17) With either single stage or the second of a two-stage, it is possible that a re-revision may be necessary - this possibility should be considered in selecting how the implants are fixed in the bone.
(20) With respect to post operative antibiotics: (a) in most cases, oral antibiotics seem to be as cost-effective as IV antibiotics and (b) at least six weeks of antibiotics are recommended if >2 of the deep specimens are culture positive for the same organism. Prolonged antibiotic therapy is considered in cases where recurrent infection is more likely.
Use search box (upper right of this page) to find more posts on these topics
Here are a few recent articles that may be of interest.
The diagnosis of shoulder PJI is complicated by the relative frequency of Cutibacterium as the infecting bacteria. Another confunder is the difficulty in differentiating between osteolysis due to particles from polyethylene failure and osteolysis fron PJI. See Loose glenoid component - is the shoulder infected?
Determing the success rates for different treatments of periprosthetic shoulder infections is difficult to assess. Many of the publications reporting different therapeutic approaches lack appropriate controls and clear measures of treatment effectiveness.
Often shoulders continue to be painful and stiff after a revision procedure. Because clinical symptoms, signs and lab tests are insensitive to the presence of Cutibacterium, the diagnosis of recurrent infection may be overlooked unless a re-revision with intraoperative cultures is performed. The lack of a re-revision procedure is not proof that an infection has been resolved. Alternatively, re-revision may be indicated for non-infectious issues and does not necessarily indicate failure of the treatment of infection.
