Periprosthetic infections: what we don't know.

Let's consider a case of an active male who had a ream and run procedure. His shoulder was somewhat stiff from the start. His stiffness did not resolve with therapy; he developed increasing pain. He had no fever, chills, or abnormal blood markers for infection.

Two years after his index procedure he had a single stage revision. At that time his synovial fluid showed 1000 neutrophils; two frozen section specimens had more than 10 cells per high-power field.

Postoperatively, he was placed on oral amoxicillin/clavulanate.

After surgery, eight tissue specimens each cultured positive for low levels of Cutibacterium.

So here are some clinically relevant questions:

(1) Were his pre-revision findings of stiffness and pain suggestive of a periprosthetic infection?

(2) Would a preoperative aspiration or arthroscopic biopsy have changed the management of this case?

(3) Were his surgical findings diagnostic of a periprosthetic infection?

(4) For this patient, how do the benefits and risks compare between a single stage and a two-stage revision?

(5) Postoperatively, while the culture results are pending (i.e. the organism is not yet unidentified), how do the benefits and risks compare between oral and intravenous antibiotics?

(6) Immediately after surgery (before culture results are available) what would be the antibiotic of choice?

(7) If the patient has ongoing pain and stiffness of the shoulder after his single stage revision, how will the surgeon know if there is a persisting infection?

A recent article, Periprosthetic Shoulder Infection management: one-stage should be the way - A systematic review and meta-analysis brought up more questions:

(8) "For this review, the rate of reinfection after a revision arthroplasty for a shoulder PJI was the main outcome assessed." How is a "reinfection" diagnosed? Does the definition require a re-operation to see if deep tissue specimens are culture positive (and for the same organism as was found in the index revision)? If a patient is doing poorly after a revision but does not have a re-operation, how does one know whether there is a "reinfection"?

(9) In this review, why is the complication rate for two-stage revision (21.26%) higher than that for one-stage revision (6.11%)? It may be that a shoulder having two procedures is more likely to have more complications than a shoulder having a single procedure. 

(10) Why was the "reinfection rate" with a single stage (one stage) revision (1.14%) lower than that after a two-stage revision (8.81%). This gets to #7 above: how does a surgeon know if there is a "reinfection" if the shoulder is not re-operated with cultures taken at the time of re-operation. Since the complication rate was three times higher with the two-stage revisions, it seems likely that more of the two-stage revisions would have had re-operations and re-culturing.

(11) Does the organism cultured from the time of revision matter to the treatment and to the outcome? The isolated bacteria reported in the analyzed studies varied widely with respect to virulence, including Cutibacterium, Coagulase-negative Staph, Methicillin resistant Staph Aureus, E. Fecalis, Strep Viridans, and Pseudomonas. Reliable studies comparing the efficacy of different surgical and antibiotic regimens will require controlling for the infecting organism.

(12) What are the indications for a two-stage revision of a periprosthetic infection?


Comments: Some things we think we know

(1) Some perioprosthetic infections are obvious (pain, swelling, drainage, fever, chills, elevated serum inflammatory markers).




While the diagnosis of PJI may not difficult, it is still important to identify the causative organism.

(2) Many periprosthetic infections have a stealth presentation (unexplained onset of pain and stiffness after a "honeymoon" period of benign post-arthroplasty recovery).



These infections are typically caused by low virulence organisms, such as Cutibacterium. Often the diagnosis is made by obtaining specimens for culture at the time of a revision procedure performed for pain and stiffness. In that the results of these cultures are not finalized until weeks after the revision, the surgical and immediate postoperative antibiotic treatment must be decided without this information.

(3) Single stage revision with thorough debridement, prosthesis exchange and post-operative antibiotics can be effective treatment of shoulder periprosthetic infections caused by Cutibacterium. (see Single-Stage Revision Is Effective for Failed Shoulder Arthroplasty with Positive Cultures for Propionibacterium).

(4) Two-stage revision is more morbid, has a higher complication rate and is more costly than a single stage revision, but can be considered in cases of obvious infection from a high virulence organism or when a prior single stage revision has failed.

(5) Postoperative intravenous antibiotics are more morbid, have a higher complication rate and are more costly than oral antibiotics, but can be considered in cases of obvious infection from a high virulence organism (see The Use and Adverse Effects of Oral and Intravenous Antibiotic Administration for Suspected Infection After Revision Shoulder Arthroplasty).

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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).

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.

Betadine and topical vancomycin may be of value in reducing the rate of periprosthetic infection.[Vancomycin powder embedded in collagen sponge decreases the rate of prosthetic shoulder infection] [Dilute povidone-iodine irrigation reduces the rate of periprosthetic joint infection following hip and knee arthroplasty: an analysis of 31,331 cases][A systematic review and meta-analysis comparing intrawound vancomycin powder and povidone iodine lavage in the prevention of periprosthetic joint infection of hip and knee arthroplasties][Systematic review and meta-analysis of intrawound vancomycin in total hip and total knee arthroplasty: a continued call for a prospective randomized trial.]

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.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

What antibiotic treatment should be used after revision shoulder arthroplasty?

Oral and IV Antibiotic Administration After Single-Stage Revision Shoulder Arthroplasty: Study of Survivorship and Patient-Reported Outcomes in Patients without Clear Preoperative or Intraoperative Infection

Most periprosthetic infections (PJI) shoulder are caused by Cutibacterium.

Infections by these organisms do not give rise to the usual signs typical of infections with other organisms, such as fevers, erythema, swelling, elevated white count, elevated markers of inflammation, and abnormal results on frozen section of tissue samples. Instead, shoulder PJI from Cutibacterium often present as otherwise unexplained pain and stiffness after a previously successful arthroplasty. As a result, the diagnosis of Cutibacterium PJI cannot be reliably made at the time of surgery, but must wait until the results of intraoperative cultures are available days or weeks after the revision procedure. Therefore the surgeon must make a decision regarding the use, type, and route of antibiotic treatment at the time of surgery before the culture results are known. 

The potential advantages to starting IV antibiotics prior to hospital discharge in patients with a high suspicion for PJI include potentially increased efficacy of the IV therapy in infection eradication and establishment of a peripherally inserted central catheter (PICC) prior to discharge. Disadvantages include the risks associated with insertion of a PICC. Potential advantages of using oral antibiotics for patients with a low suspicion for PJI include lower cost and convenience. Disadvantages of oral therapy include concerns about consistency of administration and achievement of the desired antibiotic serum levels.

In this study of 92 patients without purulence or sinus tracts having single-stage revision for failed shoulder arthroplasty, the authors determined the infection-free survival, revision-free survival, complications, and patient-reported outcomes for patients selected by the surgeon to receive oral or intravenous (IV) antibiotics after revision arthroplasty. IV antibiotics were administered if the surgeon had a high index of suspicion for infection, and oral antibiotics were given if there was a low suspicion. Variables considered for IV antibiotics included young age, male sex, prior infection, humeral component loosening, osteolysis, synovitis and high levels of Cutibacterium on the unprepared skin of the shoulder. Antibiotic therapy was modified based on intraoperative culture results. 

In this study, surgeons correctly predicted the presence or absence of PJI (as indicated by multiple positive cultures of specimens from the revision surgery) in 72% of the 92 cases. Subsequent re-revision surgery was required in 17 (18%) of the patients; 8 of these 17 patients had ≥2 positive cultures at re-revision. 

Infection-free survival, revision-free survival, and patient-reported outcomes were similar in high-risk patients placed on IV antibiotics and low-risk patients placed on oral antibiotics, even though the bacterial loads at surgery for the IV group were significantly higher than those for the oral antibiotic group. 

Patients requiring a change from oral to IV antibiotics based on positive cultures had similar survivorship compared with those initially treated with IV antibiotics. 

While they had different preoperative and intraoperative characteristics, the IV and oral antibiotic groups had similar postoperative Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES), and satisfaction scores. Patients demonstrated a median decrease in the VAS pain score of 4 points and a median improvement in the SST score of 3 points, both of which surpass the minimum clinically important difference for these instruments.

Patients receiving IV antibiotics had a higher rate of antibiotic-related adverse events.

Post-revision antibiotic therapy was associated with an infection-free survival rate of 91% at a mean of >4 years of follow-up. 

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: click on this link

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

Cutibacterium and revision shoulder arthroplasty

Unexpected positive cultures after revision shoulder arthroplasty: does it affect outcome?

The term "unexpected positive cultures" may not be the best term: if cultures were not expected to be positive, why were they taken in the first place?

These authors note that many studies have found a high rate of positive cultures after revisions of failed shoulder arthroplasties that did not show the classic signs of infection (fever, chills, and elevated inflammatory markers in blood and joint fluid)

The purpose of this study of arthroplasty revisions performed on shoulders without obvious preoperative evidence of infection was to compare the patient-reported outcomes for those patients with and without substantially positive intra-operative cultures. 

Preoperative antibiotics were withheld until biopsy specimens were obtained. Thereafter, an intravenous (IV) dose of either 1.5 g cefuroxim or 1 g dicloxacillin was administered. At surgery an "infection-type" revision was performed with debridement of scar and cement, antibiotic irrigation, and single stage exchange of implants. After surgery an "infection-type" antibiotic regimen was implemented: postoperative IV antibiotics  for the first 24 hours followed by either oral or IV antibiotic treatment covering at least C acnes until the final culture result was available. If cultures exhibited growth at readings up to the fourth postoperative day, then 2 weeks of IV treatment were initiated, followed by 4 weeks of oral treatment. If cultures were positive at the reading on the 14th postoperative day, then an additional 4 weeks of oral treatment were recommended. 

Five biopsies were obtained from 124 revisions. 27 shoulders (22%) had 3 or more positive cultures for the same organism. Cutibacterium acnes accounted for 67% of these (18/27).

All patients were assessed using the Oxford Shoulder Score (OSS) and range of motion preoperatively and after at least a 2-year follow-up (median follow-up of 29 months.  At baseline, the OSS was 22 in both the culture-negative and the culture positive groups. At follow-up, the OSS was similar for the two groups: 37 in the culture-negative group and 35 in the culture positive group. One might conclude from this result that the presence of positive cultures was unimportant. A more attractive conclusion is that the shoulders with three or more out of five positive cultures were adequately managed by the surgical removal of potentially biofilm-coated implants, thorough debridement and a vigorous postoperative antibiotic protocol. 

The results of this study are remarkably similar to those of another recent publication: Single-Stage Revision Is Effective for Failed Shoulder Arthroplasty with Positive Cultures for Propionibacterium

In that study, 55 shoulders without obvious clinical evidence of infection had a single-stage revision arthroplasty. The patient self-assessed functional outcomes for shoulders with ≥2 positive cultures for Propionibacterium (the culture positive group) were compared with shoulders with no positive cultures or only 1 positive culture (the control group). 

The surgery consisted of complete prosthesis removal, debridement, antibiotic irrigation and reimplantation of a new prosthesis After all culture specimens were obtained, 15 mg/kg of vancomycin and 2 g of ceftriaxone were administered intravenously. In cases in which there was a high index of suspicion, the patient was maintained on intravenous ceftriaxone through a peripherally inserted central catheter (PICC) (the Red Protocol). If the cultures were negative at 3 weeks, all antibiotics were discontinued. In cases in which there was a low index of suspicion for infection, patients were placed on oral amoxicillin and clavulanate (the Yellow Protocol) either until the cultures were negative at 21 days or until 2 cultures with the same bacterial species became positive.

The culture-positive group had 89% male patients, with a mean age (and standard deviation) of 63.5 ± 7.2 years. The mean Simple Shoulder Test (SST) scores for the 27 culture-positive shoulders improved from 3.2 ± 2.8 points before the surgical procedure to 7.8 ± 3.3 points at a mean follow-up of 45.8 ± 11.7 months after the surgical procedure (p < 0.001), a mean improvement of 49% of the maximum possible improvement. 

The control group had 39% male patients, with a mean age of 67.1 ± 8.1 years. The mean SST scores for the 28 control shoulders improved from 2.6 ± 1.9 points preoperatively to 6.1 ± 3.4 points postoperatively at a mean follow-up of 49.6 ± 11.8 months (p < 0.001), a mean improvement of 37% of the maximum possible improvement. 

Subsequent procedures for persistent pain or stiffness were required in 3 patients (11%) in the culture positive group and in 3 patients (11%) in the control group; none of the revisions were culture-positive.

The authors concluded that the clinical outcomes after single-stage revision for Propionibacterium culture-positive shoulders were at least as good as the outcomes in revision procedures for control shoulders and that two-stage revision procedures may not be necessary in the management of these cases.

In sum, both groups of authors treated all of these revisions with a type of surgery and postoperative antibiotic regimen anticipating that a substantial percentage of the intraoperative cultures would be positive - even though there was not compelling preoperative evidence of infection. This is important because it is recognized that many, if not most, shoulder periprosthetic infections have a "stealth" rather than an "obvious" presentation.

How you can support research in shoulder surgery Click on this link.

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).

Antibiotic protocol after revision shoulder arthroplasty

The Journal of Bone and Joint Surgery has provided this useful summary of a recent article on antibiotics after revision arthroplasty (see this link).

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How you can support research in shoulder surgery Click on this link.

To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

Antibiotics in suspected shoulder arthroplasty infections

The Use and Adverse Effects of Oral and Intravenous Antibiotic Administration for Suspected Infection After Revision Shoulder Arthroplasty

These authors point out that when performing revision shoulder arthroplasty, surgeons do not have access to the results of intraoperative culture specimens and will, therefore, administer empiric antibiotics to cover for the possibility of deep infection until the culture results are finalized.

The purpose of their study was to report the factors associated with the initiation, modification, and adverse events of 2 different postoperative antibiotic protocols in a series of revision shoulder arthroplasties.

175 patients undergoing revision shoulder arthroplasty were treated with either a protocol of intravenous (IV) antibiotics if there was a high index of suspicion for infection (red protocol) or a protocol of oral antibiotics if the index of suspicion was low (yellow protocol). Antibiotics were withdrawn if cultures were negative and were modified as indicated if the cultures were positive.

On univariate analysis, factors significantly associated with the initiation of IV antibiotics were male sex (p < 0.001), history of infection (p < 0.001), intraoperative humeral loosening (p = 0.003), and membrane formation (p < 0.001). 

On multivariate analysis, male sex (p = 0.003), history of infection (p = 0.003), and membrane formation (p < 0.001) were found to be independent predictors of the initiation of IV antibiotics. 

On the basis of preoperative and intraoperative characteristics, surgeons anticipated the culture results in 75% of cases, and modification of antibiotic therapy was required in 25%. The modification from oral to IV antibiotics due to positive culture results was made significantly more often in male patients (p < 0.001). 

Adverse effects of antibiotic administration occurred in 19% of patients. The rates of complications were significantly lower in the patients treated with oral antibiotics and a shorter course of antibiotics (p < 0.001).

Comment: It is of interest that - using only the history and intraoperative findings - these surgeons were able to anticipate the results of intraoperative cultures in 3/4ths of the cases, enabling the optimal antibiotic protocol to be instituted at the time of surgery in these cases.

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To see a YouTube of our technique for total shoulder arthroplasty, click on this link.
To see a YouTube of our technique for a reverse total shoulder arthroplasty, click on this link.

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We have a new set of shoulder youtubes about the shoulder, check them out at this link.

To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Do antibiotics in irrigation fluid actually kill bacteria and do they kill host cells?

Polymyxin and Bacitracin in the Irrigation Solution Provide No Benefit for Bacterial Killing in Vitro

These authors compares the antimicrobial efficacy and cytotoxicity of an irrigation solution containing polymyxin-bacitracin with other commonly used irrigation solutions in vitro.

They exposed Staphylococcus aureus and Escherichia coli to irrigation solutions containing topical antibiotics (500,000-U/L polymyxin and 50,000-U/L bacitracin; 1-g/L vancomycin; or 80-mg/L gentamicin), as well as commonly used irrigation solutions (saline solution 0.9%; povidone-iodine 0.3%; chlorhexidine 0.05%; Castile soap 0.45%; and sodium hypochlorite 0.125%). Following 1 and 3 minutes of exposure, surviving bacteria were manually counted. Failure to eradicate all bacteria in any of the 3 replicates was considered not effective for that respective solution. 

Cytotoxicity analysis in human fibroblasts, osteoblasts, and chondrocytes exposed to the irrigation solutions was performed by visualization of cell structure and was quantified by lactate dehydrogenase (LDH) activity. Efficacy and cytotoxicity were assessed in triplicate experiments, with generalized linear mixed models.

Polymyxin-bacitracin, saline solution, and Castile soap at both exposure times were not effective at eradicating S. aureus or E. coli. In contrast, povidone-iodine, chlorhexidine, and sodiumhypochlorite irrigation were effective against both S. aureus and E. coli. Vancomycin irrigation was effective against S. aureus but not against E. coli, whereas gentamicin irrigation showed partial efficacy against E. coli but none against S. aureus. 

Within fibroblasts, the greatest cytotoxicity was seen with chlorhexidine (mean 49.38%), followed by Castile soap (33.57%) and polymyxin-bacitracin (8.90%). Povidone-iodine showed the least cytotoxicity of the efficacious solutions (5.00%). Similar trends were seen at both exposure times and across fibroblasts, osteoblasts, and chondrocytes.

Conclusions: Irrigation with polymyxin-bacitracin was ineffective at eradicating these bacteria and were inferior to povidone-iodine. On the other hand, Chlorhexidine lavage conferred the greatest in vitro cytotoxicity.

The authors conclude that the addition of polymyxin-bacitracin to saline solution irrigation has little value and suggest that Povidone-iodine (Betadine) may be a more effective and safer option.

Comment: While this is not an in vivo study and while it does not test the effects of the different irrigating solutions against the organisms commonly causing shoulder periprosthetic infections (Cutibacterium, coagulase-negative Staph), these results are of interest to shoulder surgeons. First it points out that the effectiveness of various irrigation solutions cannot be assumed, but rather it needs to be tested against the organisms we commonly encounter. Secondly, it points out that irrigation solutions may have harmful effects on the cells of the patient. We note that the use of some of the irrigation solutions being marketed for the use in shoulder cases(see this link) may be called int o question by this article.

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To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Be sure to visit "Ream and Run - the state of the art"  regarding this radically conservative approach to shoulder arthritis at this link and this link. Also see the essentials of the ream and run.

Antibiotics after total joint replacement - how long should they be given?

Extended Oral Antibiotic Prophylaxis in High-Risk Patients Substantially Reduces Primary Total Hip and Knee Arthroplasty 90-Day Infection Rate

These authors conducted a retrospective cohort study performed on 2,181 primary total knee arthroplasties (TKAs) and primary total hip arthroplasties (THAs) carried out from 2011 through 2016 at a suburban academic hospital with modern perioperative and infection-prevention protocols. Beginning in January 2015, extended oral antibiotic prophylaxis for 7 days after discharge was implemented for patients at high risk for PJI. The percentages of patients diagnosed with PJI within 90 days were identified and compared between groups that did and did not receive extended oral antibiotic prophylaxis.

Patients were categorized into 1 of 3 groups. Group A consisted of patients who were not at risk for PJI per protocol and therefore were not given extended oral antibiotic treatment; group B, patients at risk for PJI per protocol but not given extended oral antibiotic treatment because the protocol was not yet in place; and group C, patients at risk for PJI who received extended oral antibiotic prophylaxis per protocol.

The risk factors are listed below for groups B and C

The oral antibiotic protocol for high-risk patients consisted of cefadroxil, 500 mg twice daily for 7 days. Patients who tested positive for MRSA received Bactrim DS (sulfamethoxazole and trimethoprim) twice daily for 7 days or, if they were allergic to cephalosporins with documented anaphylaxis, 300 mg of clindamycin 3 times daily for 7 days.

PJI meeting Musculoskeletal Infection Society criteria within 90 days after TJA was the outcome of interest in this study.

The 90-day infection rates were 1.0% and 2.2% after the TKAs and THAs, respectively. High-risk patients without extended antibiotic prophylaxis were 4.9 (p = 0.009) and 4.0 (p = 0.037) times more likely to develop PJI after TKA and THA, respectively, than high-risk patients with extended antibiotic prophylaxis.

The adverse reactions to antibiotics are shown below

The authors concluded that extended postoperative antibiotic prophylaxis led to a statistically significant and clinically meaningful reduction in the 90-day infection rate of selected patients at high risk for infection.

Comment: This study is of interest because it seems to run counter to the trend to minimize the use of antibiotics because of concerns related to increasing antibiotic resistance and the potential for antibiotic related problems, such as C. difficile infections.

The paper does not specify the organisms responsible for the infections observed - this would be of interest.

Finally, these data pertain to hip and knee arthroplasty. Different bacteria are found in shoulder periprosthetic infections (Propionibacterium and coagulase negative Staph), so the effectiveness of extended antibiotics in higher risk patients having shoulder arthroplasty requires independent assessment.

In any event, the identification and management of risk factors for infection is an important aspect of total joint arthroplasty and more studies of this type are needed. Balancing the risks and benefits of extended antibiotics in patients of increased risk is a priority.

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Antibiotics do not sterilize the skin of shoulders undergoing joint replacement

Preoperative Doxycycline Does Not Reduce Propionibacterium acnes in Shoulder Arthroplasty

These authors state that propionibacterium is the most common bacteria associated with infection after shoulder arthroplasty. 

They conducted a randomized controlled trial in an effort to determine whether adding preoperative intravenous doxycycline to their standard intravenous cefazolin reduced the prevalence of positive propionibacterium cultures of skin and deep tissues at the time of prosthetic joint implantation.

Patients had a standard skin preparation with both alcohol and chlorhexidine. After the infusion of systemic antibiotics, specimens were taken, for aerobic and anaerobic cultures, via (1) an excisional tissue biopsy of the skin edge, (2) a tissue swab of the superficial dermal tissue within the incision, and (3) a tissue swab of the glenohumeral joint. All cultures were maintained for 14 days. 

Twenty-one shoulders (38%) had at least 1 positive culture for propionibacterium.The greatest numbers of culture-positive samples were obtained from the skin (30%), followed by dermal tissue (20%) and the glenohumeral joint (5%).

There was no significant difference in culture positivity between the group treated with cefazolin alone (10 [37%] of 27 patients) and the combined doxycycline and cefazolin group (11 [38%] of 29 patients) (p = 0.99). 

Propionibacterium culture positivity was significantly more frequent for younger patients, males, and patients with a lower comorbidity index.

Comment: This study demonstrates that systemic antibiotics fail to eliminate the propionibacterium that inhabit the sebaceous glands of normal skin. Likewise, this and prior studies have shown that skin surface preparation fails to eliminate these bacteria. As a result of these two failures, the skin incision for shoulder arthroplasty can transect these sebaceous glands allowing the propionibacterium to inoculate the arthroplasty wound and potentially form a resistant biofilm on the implants.

It is well known that propionibacterium are sensitive to cephalosporins (see this link) so the question is not whether additional antibiotics would help, but rather whether systemic antibiotics penetrate the sebaceous glands sufficiently to kill the bugs there. The answer appears to be "no".
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What is an infection anyway?

Low-grade infections in nonarthroplasty shoulder surgery

These authors reviewed 35 patients presenting with suspected low-grade infection in which biopsy specimens taken at revision surgery. Patients presented with symptoms akin to resistant postoperative frozen shoulder (persistent pain and stiffness, unresponsive to usual treatments).

Positive cultures were identified in 21 cases (60.0%), of which 15 were male patients (71%). Of all patients with low-grade infection, half were male patients between 16 and 35 years of age.

Propionibacterium acnes and coagulase-negative staphylococcus were the most common organisms isolated (81.1% [n = 17] and 23.8% [n = 5], respectively).  The mean time from index surgery to diagnosis for P. acnes –positive cases was 1.2 years (60.3 weeks).

Not all patients with clinically suspected low-grade infections presentedwith positive microbiologic cultures, despite use of enhanced culture methods. The authors suggest that the suspect organisms may be nonculturable on routine culture media or that the suspect organism was in an area of the shoulder not sampled. Of 14 negative culture cases, 9 were treated with early empirical antibiotics (64.3%); 7 patients reported symptomatic improvement (77.8%). Of 5 patients treated with late empirical antibiotics, 4 stated improvement.  Again, the majority of the patients with negative cultures reported improvement in their pain, stiffness, and range of movement after early empirical antibiotic treatment (doxycycline and amoxicillin, n = 8 [88.9%]; gentamicin and teicoplanin, n = 1 [11.1%]). More than half of these patients (n = 6 [66.7%]) stated that their pain completely resolved

Comment: This series of cases points to the complex and uncertain relationship between cultures and clinical findings. Patients without the characteristic signs of infection can have positive cultures. Patients with negative cultures can respond to antibiotics.

In such cases, we must be careful to use the term "positive cultures" rather than "infection" and to relate the apparent improvement after administration of antibiotics as an "association" rather than a "treatment".

For more, see the below:

What is a "periprosthetic shoulder infection"? A systematic review of two decades of publications.

These authors point out that while as many as 50% of revision shoulder arthroplasties are culture positive, a consistent, clinically useful definition of a "periprosthetic shoulder infection" is lacking. They conducted a systematic review of the published literature with respect to (1) the definition of a "periprosthetic shoulder infection", (2) the pre-operative evaluation for possible infection, and (3) the harvesting and culturing of specimens at the time of surgical revision.

They found a remarkable lack of consistency in the way different authors defined an 'infection', in the way authors evaluated patients with possible infections before surgery and in the way authors obtained and analyzed specimens obtained for culture harvested at the time of the surgical revision of failed shoulder joint replacements.

This inconsistency makes it very difficult to compare different treatment approaches to failed shoulder joint replacements, recognizing that some of them will have substantial bacteria in the joint, the presence of which may go unrecognized until the culture results are finalized at 2 to 3 weeks after surgery.

Comment: It is critically important not to combine, confuse or commingle data from 

"obvious infections" (i.e. those with swelling, redness, drainage, fever, chills, elevated serum markers of inflammation) where the diagnosis of infection is apparent 

with cases of 

"stealth" presentation (i.e. the unexplained onset of pain and stiffness of the shoulder after a 'honeymoon' of good function in which specimens obtained at revision surgery are strongly positive for organisms such as Propionibacterium).

Here's an example of a stealth presentation:

A 50 year old patient presented desiring a ream and run arthroplasty for severe glenohumeral arthritis

After surgery, the shoulder progressively regained comfort and function. Subsequently, however it started to become stiff and painful without obvious explanation. Eight years after his shoulder arthroplasty, the patient returned to the office with no clinical, laboratory, or radiographic evidence of infection.

A single stage revision was performed (soft tissue releases, prothesis exchange) without any evidence of inflammation, joint fluid, loosening, or osteolysis. Five explant and tissue cultures were sent. The patient was discharge on the yellow protocol (Augmentin) until the results of the cultures were final.

The culture results were
Humeral head explant: 3+ Propionibacterium
Humeral stem explant: no growth
Collar membrane: 1+ Propionibacterium
Humeral periosteum: 1+ Propionibacterium
Joint capsule: no growth

At this point the red protocol (IV ceftriaxone) was started and continued for 6 weeks followed by a 6 month course of Augmentin. The patient has a comfortable shoulder and has regained most of the lost shoulder motion.

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