Sunday, April 15, 2018

Pain and stiffness after shoulder arthroscopy - is Propionibacterium a factor?

Propionibacterium acnes infection in shoulder arthroscopy patients with postoperative pain

These authors point out that Propionibacterium are suspected are often recovered from deep cultures at the time of revision for failed arthroplasty. They sought to identify Propionibacterium in revisions for shoulder arthroscopy failures due to pain and stiffness.

They prospectively collected data on all shoulder arthroscopies performed by the senior author from January 1, 2009, until April 1, 2013. A total of 1,591 shoulder arthroscopies were performed during this period, 68 (4.3%) of which were revision procedures performed for pain, stiffness, or weakness. Cultures were taken in all revision shoulder arthroscopy cases performed for pain, stiffness, or weakness.  None of these patients exhibited overt clinical signs of infection such as fever or wound drainage. Although all of the patients had pain and complained of stiffness, none showed significant range-of-motion limitations characteristic of the diagnosis of adhesive capsulitis. For all patients, 2 intraoperative specimens were prospectively collected, submitted for culture, and held for a minimum of 14 days by the hospital microbiology laboratory. In all cases, tissue cultures were obtained from the synovium of the rotator interval, with additional cultures obtained from other focal areas of synovitis, from retained sutures or implants, and from the subacromial space. All cultures were kept as solid tissue, and the tissue was immediately placed in a culture swab container to ensure increased yield and to minimize contamination by eliminating any need for subsequent tissue transfer during the microbiology preparation

A total of 20 revision arthroscopies (29.4%) had positive culture findings, and 16 (23.5%) were positive for Propionibacterium.  32% of the male patients were culture positive while 13% of the female patients were culture positive. All shoulders with proven positive cultures were found to have evidence of synovitis on diagnostic arthroscopy.


In addition, 2 cultures were taken from each of a cohort of 32 primary shoulder arthroscopy cases without concern for infection. In the control group, 1 patient (3.2%) had P acnes growth.

The authors conclude that the presence of Propionibacterium in shoulders undergoing revision shoulder arthroscopy is higher than previously published. Propionibacterium may contribute to refractory postoperative pain and stiffness after shoulder arthroscopy.

Comment: This is an important study in that it indicates that Propionibacterium may be introduced at the time of arthroscopy, perhaps related to the passage of cannulas and suture from the skin through the dermis and into the joint. If this is the case, patients with prior arthroscopy may be at increased risk for Propionibacterium infection if a subsequent arthroplasty is carried out.

It is of note that in this study, only two tissues samples were submitted for culture. It is known that harvesting more specimens increases the chances of identifying Propionibacterium. Taking more specimens might have yielded a higher rate of culture positivity. It would be of interest to know how many shoulders had synovitis and negative cultures.
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Supporting progress in shoulder surgery

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Wednesday, April 11, 2018

Is there evidence that stemless shoulder arthroplasty is better or safer?

Sidus Stem-Free Shoulder System for primary osteoarthritis: short-term results of a multicenter study

These authors reviewed their experience with 105 shoulders treated with the Sidus Stem-Free Shoulder System at 9 centers in Europe at 2 or more years after surgery.



The main indication was primary osteoarthritis (80.1%). Total shoulder arthroplasty was performed in 73 cases and hemiarthroplasty in 32. Clinical scores were improved.  Radiologically, neither migration nor loosening was found. However, radiolucent lines of 2 mm or greater could be detected around the glenoid in 2 cases, but none of them have had clinical relevance yet. The overall complication rate was 6.7%, and the revision rate was 0%.

The authors concluded that patients receiving the Sidus Stem-Free Shoulder System achieve good clinical and radiologic short term results that are comparable with the results of other stem-free shoulder implants.

Comment: The motivation for pursuing 'stemless' humeral components apparently comes from concern about "stem-related complications", including intraoperative humeral fracture, postoperative periprosthetic humeral fracture, proximal humeral bone loss  due to stress shielding, humeral stem loosening, osteolysis, and difficulty in explanting a well-fixed stem in the case of revision.

The complication rate with this stemless implant was 6.7% including one humeral fracture.  There was a 9.5% rate of radiolucent lines around the glenoid components. In their review of the literature on stemless implants, these authors point out revision rates for stemless shoulder arthroplasties ranging from 2 to 11% and relatively high rates of glenoid radiolucent lines.

An important perspective can be gained by comparing theses complication and revision rates to those from a recent review of complications for shoulder arthroplasty (see this link) which found that humeral complications in shoulder arthroplasty were relatively uncommon: " Humeral component failure occurred in 47 shoulders, for a prevalence of 0.2%. Stem loosening appeared to be dependent on the glenoid implant status in TSA, rather than the mode of humeral stem fixation."
"Periprosthetic humeral and glenoid fractures demonstrated a prevalence of 1.0%"

The data in this paper do not provide evidence that a stemless humeral implant is superior to an impaction grafted thin stem (see this link), which avoids each of the "stem-related complications" listed above using a conventional implant that is applicable to most shoulders without limitations related to bone quality:


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Shoulder fusion - difficult for surgeon and patient

Long-Term Outcomes of Glenohumeral Arthrodesis

These authors reviewed 29 patients with primary glenohumeral arthrodesis performed between 1992
and 2009. Surgical indications included rotator cuff arthropathy and pseudoparalysis (n = 7), neurologic injuries (n = 12), chronic infection (n = 3), recurrent dislocations (n = 3), and proximal humeral or shoulder girdle tumors (n = 4). Surgical fixation techniques included plates and screws in 18 patients and screws only in 11 patients.

All patients were examined, with a mean follow-up of 12 years (range, 2 to 22 years). Twelve patients (41%) had postoperative complications, including 6 periprosthetic fractures, 7 nonunions, and 3 infections. Eleven patients (38%) required additional surgical procedures after arthrodesis, including revision internal fixation to achieve glenohumeral fusion after nonunions (n = 7), irrigation and debridement with antibiotic treatment for deep infections (n = 2), open reduction and internal fixation to treat fracture (n = 2), and implant removal to treat symptomatic patients (n = 3). Patients experienced reasonable overall pain relief. The mean postoperative scores were 35 points for the Subjective Shoulder Value, 58 points for the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and 54 points for the Short Form-36. Eighty-seven percent of patients reported postoperative limitations. Patients with neurologic injuries had worse functional outcomes.

Comment: Shoulder arthrodesis is not commonly performed, but it is procedure that should be considered in patients with deltoid paralysis and in young patients with intractable instability. 

In young patients, we use a reasonably cosmetic technique that preserves the deltoid and most of the cuff muscles. The shoulder is approached through a standard deltopectoral incision. The subscapularis is incised from the lesser tuberosity to be closed at the end of the case. The cartilage is removed from the humeral and glenoid articular surfaces.

The undersurface of the acromion is curetted. 



 While some advocate fusing at higher angles of elevation, we've found that fusion in the 0,0,60 position is most comfortable because it allows the scapula to be in an anatomic position when the arm is at rest by the side. This position also enables the surgeon to use a sling rather than a cast or brace for postoperative immobilization.


Fixation is achieved by three screws placed from the humerus into the solid bone of the glenoid.
Fixation is augmented by placing an iliac crest autograft between the acromion and the humeral head.


 When stability cannot be achieved in the manner described above, a contoured plate is added from the scapular spine to the lateral humerus.

Non-union and fracture can complicate shoulder fusion. We also encounter patients whose shoulder was fused in too much abduction, too much flexion or too much external rotation. In these cases a corrective osteotomy may be needed



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Tuesday, April 10, 2018

How dirty is your duck?

Ugly ducklings—the dark side of plastic materials in contact with potable water

Bath todays are in common use (see this link).



They pose an interesting insight into biofilm formation and flexible plastic materials, water, external microbial and nutrient contamination,

These authors characterized biofilm communities inside 19 bath toys used under real conditions. All examined bath toys revealed slimy biofilms on their inner surface.



Total bacterial numbers averaged 5.5 million cells/cm2 (clean water controls), 9.5 million cells/cm2 (real bath toys), and 74  million cells/cm2 (dirty water controls). Bacterial community compositions were diverse, showing many rare taxa in real bath toys and rather distinct communities in control bath toys, with a noticeable difference between clean and dirty water control biofilms.

The authors argue that bath toy biofilms are influenced by (1) the organic carbon leaching from the plastic material, (2) the chemical and biological water quality, (3) additional nutrients from care products and human body fluids in the bath water, as well as, (4) additional bacteria from dirt and/or the end-users’ microbiome.

They conclude that toys from real households are colonized by dense biofilms with complex bacterial and fungal communities.

Comment: The purpose of this post is to remind us that biofilms form on plastic as well as metal. Of interest is that the biofilm did not come off the plastic easily - it had to be removed using an electric toothbrush (Oral-B®, Advanced Power).

These findings may have relevance in the revision of the plastic components of a total shoulder when infection is suspected.

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The B2 retroverted glenoid is an augmented glenoid needed?

In performing a total shoulder for the B2 retroverted glenoid with posterior decentering, some surgeons prefer to normalize glenoid version with anterior glenoid bone reaming, posterior bone grafting or posteriorly augmented glenoids, we have found that most cases can be managed with a standard glenoid component accepting the retroversion as described in this link.

Here is a recent case of a B2 glenoid with preoperative retroversion of 25 degrees and posterior decentering.


A total shoulder arthroplasty was performed with a standard glenoid component without changing the glenoid version. Note the re-centering of the humeral head.


 This approach is in contrast to the use of special posteriorly augmented glenoid components as discussed in a recent article (see this link). Here ar examples of augmented components.

Here is an example from that article. 



We suggest that the minor degree of retroversion shown here could be well managed with a standard, non-augmented glenoid component as shown above.

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Saturday, April 7, 2018

Sebaceous gland activity by age and sex - significance for Propionibacterium

Age-related Changes in Sebaceous Gland Activity

Sebaceous secretion is low in children and begins to increase in mid- to late childhood under the influence of androgens. This rise continues until the late teens, after which no further significant change takes place until late in life.

In elderly men, sebum levels remain essentially unchanged from those of younger adults until the age of 80. In women, sebaceous secretion decreases gradually after menopause and shows no significant change after the 7th decade.



The most likely explanation for the decrease in sebaceous gland secretion with age in both men and women is a concomitant decrease in the endogenous production of androgens.

Comment: The dermal sebaceous glands are an important site of Propionibacterium. It is possible that the difference in Propionibacterium prevalence between males and females is related to the difference in sebum production between the sexes.

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Ream and run - remodeling at one year.


 A 62 year old active man presented with severe pain a year ago, unable to perform any of the functions of the Simple Shoulder Test and the x-rays below


One year after surgery he could perform 10 of the 12 SST functions and had the x-rays shown below showing glenoid remodeling


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