Wednesday, June 20, 2018

Revision arthroplasty: risky business

Risk factors for and timing of adverse events after revision total shoulder arthroplasty 

These authors sought to identify risk factors for unplanned readmission and perioperative complications following revision total shoulder arthroplasty, risk-stratify patients based on these risk factors, and assess timing of complications in patients from the ACS-NSQIP database from 2011 to 2015.

Of 809 revision patients, 61 suffered a perioperative complication or readmission within 30 days of discharge. Multivariate analysis identified operative time, BMI>40, infection etiology, high white blood cell count, and low hematocrit as significant independent risk factors for 30-day complications or readmission after revision surgery. 

Having at least one significant risk factor was associated with 2.71 times risk of complication or readmission within 15 days compared to having no risk factors. The majority of unplanned readmission, return to the operating room, open/deep wound infection, and sepsis/septic shock occurred within two weeks of revision surgery. 

Comment: We are often tempted to "fix" a failed shoulder arthroplasty. This article reminds us that there are major risks of revision, especially in patients with the factors identified. The less healthy the patient, the greater the risk of complications and readmissions.

=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Failure of attempted rotator cuff repair

Recurrent rotator cuff tear: is ultrasound imaging reliable?

These authors point out that " Recurrent rotator cuff tears after rotator cuff repair (RCR) are common and found to be a major cause of postoperative pain. Retear rates are approximated at 7% to 17% for small tears and up to 41% to 94% for large and massive tears.  Retears most commonly occur up to 6 months after the operation."

The aim of their study was to assess the reliability of ultrasonography (US) for the detection of recurrent rotator cuff tears in patients with shoulder pain after RCR. 

They retrospectively analyzed the data of 39 patients with an average age of 66 years (range, 39-81 years) with shoulder pain after arthroscopic RCR who had subsequently undergone US, followed by revision arthroscopy.

A failed cuff repair was frequently found among these 39 patients:  by US in 21 patients (54%) and by revision arthroscopy in 26 patients (67%).



Comment: This study does not present the rate of rotator cuff repair failure in the overall experience of the authors, but it is impressive that over half of the patients with shoulder pain after a cuff repair attempt had a failed repair. This study also does not present the percentage of patients with a retear that did not have shoulder pain. Both of these bits of information would be helpful in understanding the rate and clinical significance of cuff repair failure.

We are often asked to evaluate patients with pain and weakness after attempted cuff repair. We find that the diagnosis of failed repair is usually evident from the history and physical exam. We are very rarely tempted to try a "re-repair" after a prior repair attempt failure because the tissue quality and quantity are typically inadequate for a robust repair.

For many such cases the greatest value procedure is often a "smooth and move" as described here:
Treatment of irreparable cuff tears with smoothing of the humeroscapular motion interface without acromioplasty


=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Do Propionibacterium grow on hair?

Spatial and Environmental Variation of the Human Hair Microbiota
<ScientifiC Reports | (2018) 8:9017 | DOI:10.1038/s41598-018-27100-1>

These authors point out that the skin is a complex living ecosystem harboring diverse microbial communities. Its highly variable properties and influence of intrinsic and extrinsic factors creates unique microenvironments where niche-specific microbes thrive. As part of the skin, hair supports its own microbial habitat that is also intra and inter-personal variable.

They explored the hair microbiota from scalp and pubic regions in healthy adults to investigate how the hair shaft microenvironment varies microbially. Their results suggest that there are distinct differences between the microbial communities identified on hair shafts originating from different parts of the body. The taxonomic composition of the communities from different hair sources are most reminiscent of those identified from their associated cutaneous region.

Their study confirms that human hair shafts harbor unique bacterial communities, distinctive from that of the hair follicle and more reminiscent of its associated cutaneous region. Staphylococcus, a common genera found in the skin, was also found to be abundant in hair. However, Propionibacterium, a predominant bacterium that colonizes the skin and hair follicles, is noticeably absent in hair samples. The hair shaft environment may be unfavorable for growth of Propionibacterium which prefer low oxygen levels and high sebum content as that of the hair follicle.

Comment: This study suggests that hair removal may not be of major benefit in reducing the risk of Propionibacterium colonization of a surgical wound.

=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Propionibacterium DNA in normal shoulders

Cutibacterium acnes and the shoulder microbiome

These authors used DNA sequencing technologies to gain insights into the likely sources of Cutibacterium acnes (formerly Propionibacterium acnes) infections within the shoulder. Basically, their question was "do normal deep tissues of the shoulder harbor low levels of Propionibacterium that could be stimulated to grow by surgery?"

They collected tissue samples were collected from the skin, subcutaneous fat, anterior supraspinatus tendon, middle glenohumeral ligament, and humeral head cartilage of 23 patients (14 male and 9 female patients) during primary arthroplasty surgery. All samples were collected in operating rooms with vertical laminar airflow and micro-particulate air filtration, a new sterile scalpel blade was used for the collection of each tissue sample, and a fresh sterile hemostat was used to grasp and transfer the tissue into a prelabeled sterile 50-mL Falcon tube containing 6 mL of nuclease-free water

Total DNA was extracted and microbial 16S ribosomal RNA sequencing was performed using an Illumina MiSeq system.

Data analysis software was used to generate operational taxonomic units for quantitative and statistical analyses.

After stringent removal of contamination, genomic DNA from various Acinetobacter species and
from the Oxalobacteraceae family was identified in 74% of rotator cuff tendon tissue samples.



C acnes (Propionibacterium) DNA was detected in the skin of 1 male patient but not in any other shoulder tissues.

Their findings indicated the presence of a low-abundance microbiome in the rotator cuff and, potentially, in other shoulder tissues. The absence of C acnes DNA in all shoulder tissues assessed other than the skin is consistent with the hypothesis that C acnes infections are derived from skin contamination during surgery and not from opportunistic expansion of a resident C acnes population residing in the shoulder joint.

Comment: While this is an interesting study, it is curious that C acnes (Propionibacterium) DNA was recovered form the skin of only one of 14 male subjects. This rate is much lower than what would be expected based on prior culture-based studies and makes one wonder about the sensitivity of the methods used in this study.

See for example
Propionibacterium persists in the skin despite standard surgical preparation

Background: Propionibacterium acnes, which normally resides in the skin, is known to play a role in surgical site infection in orthopaedic surgery. Studies have suggested a persistence of propionibacteria on the skin surface, with rates of positive cultures ranging from 7% to 29% after surgical preparation. However, as Propionibacterium organisms normally reside in the dermal layer, these studies may underestimate the true prevalence of propionibacteria after surgical skin preparation. We hypothesized that, after surgical skin preparation, viable Propionibacterium remains in the dermis at a much higher rate than previously reported. Methods: Ten healthy male volunteers underwent skin preparation of the upper back with ChloraPrep (2% chlorhexidine gluconate and 70% isopropyl alcohol). Two 3-mm dermal punch biopsy specimens were obtained through the prepared skin and specifically cultured for P. acnes. Results: Seven volunteers had positive findings for Propionibacterium on dermal cultures after ChloraPrep skin preparation. The average time to positive cultures was 6.78 days. Conclusions: This study found that Propionibacterium persists in the dermal tissue even after surface skin preparation with ChloraPrep. The 70% rate of persistence of propionibacteria after skin preparation is substantially higher than previously reported.

https://www.medscape.com/medline/abstract/25187583
=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Monday, June 18, 2018

Propionibacterium - the importance of diversity

Cutibacterium acnes (Propionibacterium acnes) and acne vulgaris: a brief look at the latest updates

Among the multiple commensal microorganisms present in the healthy skin flora, Propionibacterium is a ubiquitous gram positive anaerobic bacterium belonging to the Actinobacteria phylum, that predominantly resides deep within the sebaceous follicle in contact with keratinocytes. Conversely, at the skin surface Propionibacteria are less represented (<2% of all bacteria), in favour of Staphylococci, especially Staphylococcus epidermidis (S. epidermidis), which dominate with >27% of the total bacteria population. Specific metabolic features allow Propionibacterium to colonise the lipid-rich sebaceous follicle environment and protect skin from other harmful pathogens to preserve the stability of resident skin microbiota. In particular, it can degrade triglycerides present in sebum to generate short-chain fatty acids, including propionic acid, which accumulation participates in the maintenance of an acid skin pH.
However this organism can also act as an opportunistic pathogen.The latest findings on Propionibacterium shed light on the critical role of a tight equilibrium between its phylogenetic groups.  

While Propionibacterium is present on the skin surface at a low level, it is the dominant resident bacterial species in the sebaceous follicles. Contrary to what was previously thought, acne vulgaris is not the result of a greater proliferation of all Propionibacterium strains, as patients with acne do not harbour more Propionibacterium in follicles than normal individuals. Instead, acne might be triggered by the selection of a subset of Propionibacterium strains, including the acne-associated phylotype IA1, probably enhanced by a hyperseborrheic environment. 

In addition, biofilm formation and differences in virulence and inflammatory potential of Propionibacterium strains might enhance their pathogenicity. 

It now appears that in healthy skin, an equilibrium state exists within the skin microbiota and between the different Propionibacterium subtypes. Furthermore,  S. epidermidis and Propionibacterium interact together and are critical in the regulation of skin homeostasis. S. epidermidis is known to inhibit Propionibacterium growth.

Changes in physiological conditions may lead to an imbalance between the different skin community members, called  dysbiosis, and eventually to the selection of more pathogenic Propionibacterium strains. Disruption of the equilibrium within the skin microbiota and intrinsic properties of Propionibacterium might therefore be conducive to the activation of innate immunity, resulting in  inflammation.

This review underscores the importance of Propionibacterium phylotype IA1 in acne and suggests the implication of other members of the human cutaneous microbiome in this skin condition.

Improved understanding of the genetic and phenotypic diversity of Propionibacterium strains as well as the involvement of other bacterial species could be applied in the development of alternative and personalised therapies addressing the pathogenic strains only and leaving the commensal strains intact.

Comment: These findings emphasize the importance of strain diversity in maintaining healthy skin and may provide insight into why some shoulders are more at risk for Propionibacterium-related arthroplasty failure than others.
=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Sunday, June 17, 2018

What is the optimal position of a reverse total shoulder?

The lateralization and distalization shoulder angles are important determinants of clinical outcomes in reverse shoulder arthroplasty. 

These authors sought to determine the effect of reverse total shoulder (RSA) lateralization and distalization on final functional outcomes.

They measured the “distalization shoulder angle” (DSA)

 and the  “lateralization shoulder angle” (LSA).


in 46 patients who underwent RSA. Functional outcome and radiographs were evaluated at a minimum of 2 years postoperatively.

LSA values between 75° and 95° were correlated with better active external rotation. Postoperative active anterior elevation, Constant, and Activities of Daily Living Requiring External Rotation scores had a positive correlation with the LSA.

DSA between 40° and 65° resulted in better active anterior elevation and abduction.

However there was a lot of scatter in the data




They looked at four groups of prosthetic techniques

With the exception of the low active external rotation in Group I, there were no discernible differences in outcome among the groups.






Comment: The position of the humerus relative to the scapula after reverse total shoulder arthroplasty is determined by the prosthesis selected and the position in which it is inserted. The classical Grammont approach emphasized medialization and distalization. As shown in the diagrams below by Steve Lippitt, medialization (middle figure below) can slacken the rotators resulting in the loss of active external rotation noted in this study.



More modern approaches emphasize a more anatomic reconstruction with less distalization and more lateralization as shown below.


While the two angles described in this study are of interest, we find it simpler to measure distalization directly as shown here
 and lateralization directly as shown here

Finally, since instability is one of the most common complications of reverse total shoulder arthroplasty,    it is important to prioritize the component geometry and the component position that optimizes the stability for each patient.

=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Does attempted arthroscopic cuff repair improve shoulder activity?

Does arthroscopic rotator cuff repair improve patients’ activity levels?

These authors asked whether attempted arthroscopic cuff repair led to improvements in patients' activity level. For 281 shoulders from 273 patients with a mean follow-up of 3.7 years. Scores included the Simple Shoulder Test, Western Ontario Rotator Cuff Index, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Single Assessment Numeric Evaluation, as well as the Shoulder Activity Level:

The Simple Shoulder Test improved from 4 to 11. Other scores improved similarly except for the Shoulder Activity Level score which decreased from the preoperative score (12 vs. 11; P < .0001).






Comment: This study introduces yet another shoulder outcome scale, the Shoulder Activity Level. The value of this scale and the clinical significance of the differences noted is unclear. Perhaps most importantly, the paper does not relate the success of the repair (i.e. achieving durable cuff integrity) with the clinical outcome. Specifically, did patients with failed cuff repairs have different clinical outcomes than those with intact repairs?
=====
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 runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'