Friday, August 25, 2023

Shoulder infections - 20 things to know.



Infection can be a major complication for patients having shoulder surgery. 

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.

Prevention


Does preoperative corticosteroid injection increase the risk of periprosthetic joint infection after reverse shoulder arthroplasty? reported a significantly increased risk of PJI in patients who received corticosteroid injections (CJI) within 1 month of reverse total shoulder, but not those who received CSI more than 1 month before RSA. Alcohol abuse, chronic kidney disease, and depression were also identified as factors increasing the risk of PJI.

The authors of Effect of supplemental testosterone use on shoulder arthroplasty infection rates concluded that testosterone use within 6 months of shoulder arthroplasty may be associated with higher rates of prosthesis joint infection. 

Photodynamic therapy for Cutibacterium acnes decolonization of the shoulder dermis found that the use of photodynamic therapy did not significantly reduce dermal colonization of Cutibacterium (as determined by punch biopsy cultures) as compared to standard skin preparation. The overall positive culture rate was 54%. All positive cultures identified Cutibacterium except for one.

Effect of Making Skin Incision with Electrocautery on Positive Cutibacterium acnes Culture Rates in Shoulder Arthroplasty: A Prospective Randomized Clinical Trial discovered that cultures obtained from the incised dermal edge immediately after skin incision were less likely to be positive if electrocautery was used in making the skin incision. However, there was no significant difference in the positive culture rate in samples from gloves and forceps taken immediately prior to humeral component implantation. Thus, use of cautery did not reduce the rate of wound innoculation.


Bariatric surgery performed with the goal of reducing body mass is associated with higher risks of PJI, implant failure, and dislocation, especially if the arthroplasty is performed within two years of the bariatric surgery. [Prior bariatric surgery is associated with an increased rate of complications after primary shoulder arthroplasty independent of body mass index[Does bariatric surgery prior to primary total knee arthroplasty improve outcomes?][Does Bariatric Surgery Prior to Primary Total Hip Arthroplasty Really Improve Outcomes?]


Diagnosis


The Incidence of Subclinical Infection in Patients Undergoing Revision Shoulder Stabilization Surgery: A Retrospective Chart Review twenty-nine (27%) of 107 patients having revision surgery had positive cultures. Twenty-six patients had positive Cutibacterium cultures; these cultures took an average of 10.65 days to turn positive. The authors suggest that surgeons consider infection as a reason for lack of clinical improvement and possibly needing revision surgery after shoulder stabilization. 

In The role of sonication in the diagnosis of periprosthetic joint infection in total shoulder arthroplasty the standard synovial fluid cultures combined with intraoperative periprosthetic tissue cultures had a sensitivity of 95%, specificity of 95% and total accuracy of 95%. Sonication cultures had a sensitivity of 91%, specificity of 68% and total accuracy of 80%. 

Treatment

Outcomes after Debridement, Antibiotics, and Implant Retention for Prosthetic Joint Infection in Shoulder Arthroplasty found that 29.4% of thee patients were diagnosed as having recurrent infection on chart review.

High infection control rate after systematic one-stage procedure for shoulder arthroplasty chronic infection found that 36/40 patients had no recurrence of infection after the one stage revision. Cutibacterium was the most frequent pathogen isolated, found in 67.5% (27/40) of the patients. The infection was polymicrobial in 40% (16/40) of the cases.

One-stage revision for infected shoulder arthroplasty: prospective, observational study of 37 patients
 found that 95% did not have evidence of recurrent infection. The most commonly isolated pathogen was Cutibacterium acnes (68%), isolated alone (15 patients, 41%) or as polymicrobial infections (10 patients, 27%). 

Outcomes after resection arthroplasty versus permanent antibiotic spacer for salvage treatment of shoulder periprosthetic joint infections: a systematic review and meta-analysis found that when implant exchange after shoulder PJI is not feasible, permanent antibiotic spacers and resection arthroplasty are both salvage procedures that provide similar rates of infection eradication. Although both can decrease pain levels, the permanent antibiotic spacer may result in better functional outcomes compared with resection arthroplasty.

Comment: It is apparent that the experience in the diagnosis and treatment hip and knee PJI cannot be directly applied to the shoulder because of the difference in causative bacteria. 

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. 

Considering all of the above, an approach to the management of the failed arthroplasty is to consider the possibility of infection unless another cause of failure is evident.

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).