Propionibacterium - not only acnes, not only in the shoulder

Propionibacterium avidum – a virulent pathogen causing hip periprosthetic joint infection

These authors report four hip prosthetic joint infections caused by P. avidum in one orthopedic center in 2015. They also characterized the hemolytic and biofilm-producing capacity of the four clinical P. avidum strains and investigated their phylogenetic relationships by whole genome sequencing. On searching their records from 1997 to 2015 they  retrospectively identified 13 P. avidum PJIs, with the majority being hip-related infections (n=11).

Preoperative synovial fluid cultures were P. avidum positive in 63.6% of cases. Six out of 12 patients (50%) with available case histories were treated with an exchange of the prosthesis. In all but one of the six patients treated with debridement-retention of the prosthesis, treatment failed thus requiring a two-stage revision. 

The isolated P. avidum strains showed a more pronounced hemolytic activity, but a similar biofilm-forming ability when compared to P. acnes.

 Whole genome sequencing identified two phylogenetic clusters highly related to P. avidum PJI strains isolated in Sweden.

Comment: As we become more accurate and precise in our characterization of Propionibacterium recovered from prosthetic joint infections, it is important to recognize that P. Acnes is not the only species of clinical importance as is pointed out in this article and in these links: Propionibacterium – What we think we know today and Genome Sequence of a Novel Species, Propionibacterium humerusii.  As is true for other bacterial species, it is reasonable to expect that these other species (P. avidum, P. granulosum, P. humerusii, and perhaps others) may have different clinical features and different antibiotic sensitivities from P. acnes. We need to ask our laboratories to put forth the additional effort to speciate Propionibacterium, rather than reporting them all as "P. acnes".  As shoulder surgeons, we need to share these insights with our hip, knee and spine colleagues in that they are likely to encounter these organisms as well.

The retrospective nature of this study is very likely to underestimate the incidence of Propionibacterium in the arthroplasty revisions because the culture protocol used for these patients is not explained. Specifically, we do not know which cases were cultured, how many specimens were submitted for culture, what culture media were used, and how long the cultures were observed. It is known that unless 5 deep specimens are cultured on three different media and observed for 3 weeks, there is a substantial risk of overlooking Propionibacterium in the wound (see Origin of propionibacterium in surgical wounds and evidence-based approach for culturing propionibacterium from surgical sites).

This study does not present the data on revised joints that were culture positive for P. acnes or other Propionibacterium species during the same time interval.

Finally, this study points out that complete prothesis exchange may be necessary to resolve Propionibacterium infections.

===

The reader may also be interested in these posts:

Healing through joint replacement

Supporting progress in shoulder surgery

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book.

Click here to see the new Rotator Cuff Book

Information about shoulder exercises can be found at this link.

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

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

See from which cities our patients come.

Do surgical results keep getting better with increasing experience?

Trend Toward High-Volume Hospitals and the Influence on Complications in Knee and Hip Arthroplasty

These authors used data from the National Inpatient Sample (2000 to 2012) to quantify trends in total hip arthroplasty (THA) and total knee arthroplasty (TKA) volume. They identified elective primary THAs and TKAs and grouped them by hospital by utilizing the hospital identifier, which indicated the geographic location of the hospital. They obtained county geographic and population data from the U.S. Census, and calculated the distances between hospitals and the centroids of counties. They obtained risk-standardized surgical complication rates for hospitals (2009 to 2012)  from Medicare Hospital Compare and grouped them by hospital volume.

They found a marked increase in the number of hospitals that performed a combined volume of ≥400 elective primary THAs and TKAs. The number of elective primary TKAs and THAs performed annually increased from 343,000 to 851,000.

In 2012, 65.5% of the arthroplasties were performed in high-volume hospitals (≥400 arthroplasties annually), and 26.6% of the arthroplasties were performed in very high-volume hospitals (≥1,000 procedures annually). The proportion of arthroplasties performed in low-volume hospitals (<100 arthroplasties annually) shrank from 17.9% to 5.4%. 

Very high-volume hospitals had the lowest complication rates (2.745 per 100; 95% confidence interval [CI], 2.56 to 2.93), and low-volume hospitals had the highest complication rates (3.610 per 100; 95% CI, 3.58 to 3.64; p < 0.0001) (odds ratio, 1.327; 95% CI, 1.26 to 1.40). Each successively higher hospital volume category manifested a lower complication rate.

Using 50 miles as a radius, the percentage of the U.S. population living near a high or very high-volume hospital was still 81.9%, well above the 65.5% of procedures performed at high-volume hospitals. Their data indicated that approximately 130,000 patients annually forwent an arthroplasty procedure at a high-volume hospital despite there being a high-volume center available in their geographic area. 

Comment: The relation between the quality of the result and surgical experience is an important topic - see this recent post (link). While this study is about hips and knees and hospital rather than surgeon volume, it is important because it suggests that the effect of volume may not have a 'threshold for an optimal result', in other words, there is no obvious level above which results stop improving. If a golfer that hits 200 balls per year is not as good as one who hits 500 per year who is not as good as one who hits 1000 per year, how much better are golfers who hit 2000 per year? The answer suggested by this study is that more (volume) is more (fewer complications).

The authors also pose the interesting question - what percent of patients are willing to drive 50 miles to lower their complication rate?  The observation 130,000 patients annually forwent an arthroplasty procedure at a high-volume hospital despite there being a high-volume center available in their geographic area may be due to patient unawareness of the data relating volume to complications, to their high degree of comfort with their local provider, or to the fact that for some, 50 miles of travel may remain a substantial barrier.

Our view is that patients need to ask about the experience of their surgeon in terms of volume, results and complications so that their decisions can be well informed.

===

Consultation for those who live a distance away from Seattle.

Check out the new Shoulder Arthritis Book - click here.

Click here to see the new Rotator Cuff Book

To see the topics covered in this Blog, click here

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

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

See from which cities our patients come.

See the countries from which our readers come on this post.

Propionibacterium periprosthetic infections of hip, knee and shoulder

Treatment of prosthetic joint infections due to Propionibacterium

These authors conducted a retrospective cohort study to evaluate treatment success at 1- and 2-year follow-up after treatment of 60 Propionibacterium-associated prosthetic joint infections (PJI) of the shoulder, hip, and knee at a median duration of 21 (0.1-49) months  39 patients received rifampicin combination therapy, with a success rate of 93% (95% CI: 83-97) after 1 year and 86% (CI: 71-93) after 2 years. The success rate was similar in patients who were treated with rifampicin and those who were not.

Most of the blood tests for inflammation were unremarkable. On average 6 specimens were sent for culture and on average 3 of these were positive for Propi. The specifics of the culturing protocol for Propi is not explained.

An open debridement and prosthesis retention was performed if an early postoperative or acute hematogenous PJI was diagnosed. Those patients with a late chronic infection were managed with a 2-stage exchange arthroplasty. Patients who, preoperatively, were not suspected of having an infection, e.g. with aseptic loosening, polyethylene wear, instability, or prosthesis dysfunction, were treated with a 1-stage exchange arthroplasty. In these patients, a PJI was therefore diagnosed from positive intraoperative cultures.

The combination of surgery and long-term antibiotic treatment postoperatively resulted in an overall success rate of 93% at 1-year follow-up and 86% at 2-year followup. At two year followup 7 of 36 patients had failed - four with evidence of ongoing infection with Propionibacterium and 3 with an infection by a different organism.

Comment: One of the first things to catch our eye was the number of Propionibacterium periprosthetic infections identified for the hip and knee. Up until recently, Propi infections were thought to be primarily in the shoulder. Most of the patients presented with the 'stealth' mode typical of Propi:  49 of the 60 patients with pain and 25 with stiffness.

The results of this series combining three different joints are quite similar to those we have previously note for the shoulder. Perhaps our hip and knee colleagues should consider the possibility of Propionibacterium periprosthetic infections in those patients with apparently 'aseptic' joint pain and stiffness.

In that this was not a prospective study, it is difficult make robust conclusions about the role of Rifampin in the management of these infections. There is no question that Rifampin can complicate the postoperative course by interfering with the action other medications the patient may need.



===

Consultation for those who live a distance away from Seattle.

Check out the new Shoulder Arthritis Book - click here.

Click here to see the new Rotator Cuff Book

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

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

See from which cities our patients come.

See the countries from which our readers come on this post.

Shoulder Joint Replacement Arthroplasty - transexamic acid - topical vs IV? Will it work in the shoulder as well as in TKA and THA?

Topical Tranexamic Acid Was Noninferior to Intravenous Tranexamic Acid in Controlling Blood Loss During Total Knee Arthroplasty

These authors sought to determine how the safety and efficacy of topical tranexamic acid (TXA) compares with intravenous (IV) TXA. They conducted a blinded, controlled, randomized trial of  89 patients ≥18 years of age (mean age, 64.8 years; 74% women) who were undergoing elective unilateral primary total knee arthroplasty for osteoarthritis by an individual surgeon. 42 patients received topical and 47 IV TXA
42 patients were allocated to topical (2.0 g of TXA in 100 mL of normal saline solution directly into the surgical site, which was left undisturbed for 2 minutes before tourniquet release).  47 patients were allocated to IV TXA (a single 10-mg/kg dose of TXA 10 minutes before tourniquet release).

The topical and IV TXA groups did not differ in terms of the decrease in hemoglobin levels or  in terms of total drain outputs. 1 patient in the topical group required a blood transfusion. Postoperative complications included acute kidney injury (1 patient), myocardial infarction (1 patient), and death (1 patient) in the topical group and acute kidney injury (1 patient) in the IV group. There were no cases of deep-vein thrombosis or pulmonary embolism at 18.3 weeks postoperatively.

Comment: While  the current literature indicates that the use of TXA in total hip and knee arthroplasty is widespread, its use in shoulder arthroplasty is uncommonly reported.

Some papers at the AAOS did describe its use:

The Effectiveness of Tranexamic Acid in Reducing Blood Loss after Total Shoulder Arthroplasty

compared the effect of 100 cc of normal saline or 100 cc of normal saline with 2 g TXA by topical application into the wound at the completion of the case and found that the average blood loss recorded after surgery was 170 mL in the placebo group and 108 mL in the TXA group (p = 0.017). The average change in hemoglobin was 2.6 g/dL in the placebo group and 1.7 g/dL in the TXA group (p < 0.001).There were no transfusion requirements or postoperative complications noted in either group.

The authors of Tranexamic Acid Decreases Blood Loss Following Total Shoulder Arthroplasty used a dose of 20mg/kg IV given at the time of skin preparation. One-hundred-twenty-two consecutive patients were done between then and December 2012 and all received TXA and were included in this study (Group A). They were compared with the previous consecutive 108 patients done without TXA (Group B).

The mean dose was 1657 mg, resulting in a mean cost of $68. Statistically significant differences in both Hb loss (Group A change = 2.22 vs. Group B change 2.58, p=0.04) and Hct loss (Group A change = 6.67 vs. Group B change = 8.09, p < 0.01) were seen in the TXA group compared to the non TXA group. In patients receiving TXA, there were statistically significant decreases in the time spent in the recovery room (mean, Group A 68 mins vs. Group B 94 mins, p < 0.01) and total length of hospitalization (mean, Group A 1.16 days vs. Group B 1.36 days, p=0.03). Two patients in Group A received a blood transfusion while six patients in Group B received transfusions

A clinical trial Tranexamic Acid in Reverse Total Shoulder Arthroplasty (TXA) has been registered.


So it looks as though interest is rising in the use of this agent. Stay tuned.

===

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


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

See from which cities our patients come.

See the countries from which our readers come on this post.