Remodeling of the repaired supraspinatus tendon

 The Fate of Sutures Post Rotator Cuff Repair

These authors used ultrasound to sequentially characterize the supraspinatus insertion after arthroscopic repair in 21 patients, 14 (67%) with full thickness tears and 7 (33%) with partial thickness tears.  During each assessment the total supraspinatus tendon thickness, the thickness of tendon tissues

below and above the sutures, the anatomical footprint and the modulus of elasticity were measured. 

Longitudinal and Schematic View of the Left Supraspinatus Tendon:

(a) Anatomical footprint, 

(b) Tendon thickness at the footprint-articular junction, 

(c) Bursal to suture tendon thickness at footprint-articular junction (FAJ), 

(d) Suture to articular surface tendon thickness at FAJ, 

(e) Tendon thickness at medial tip of the suture, 

(f) Bursal to suture tendon thickness at medial tip of the suture, 

(g) Suture to articular surface tendon thickness at medial tip of the suture 

(h) Location where tendon stiffness and modulus of elasticity were measured with shear wave elastography in which a focused ultrasonic pulse provides qualitative and quantitative information on the elasticity and stiffness of a tissue.

Within the first 12 weeks after repair, the sutures migrated from the surface through to the middle of the tendon at the footprint-articular junction (i.e., ratio of tendon tissue thickness below the suture to the total tendon thickness was 0.5). 

The mean anatomical footprint increased from 8.4 mm to 9.1 mm between 8 days and 6 weeks.

Bursal thickness decreased during the 24-week period from 1.5 mm to 0.7 mm.

Tendon modulus of elasticity increased from 154 kPa to 205 kPa between 8 days and 24 weeks.

Comment: This is an interesting study that demonstrates the change in relative suture position, repair site anatomy, and structural properties of the repaired tendon. As suggested by the previous post, it would have been of interest to see how the ultrasonographic appearance correlated with the MRI appearance during this period of time after surgical repair.

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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 total shoulder arthroplasty (see this link).

The ream and run technique is shown in 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 arthroplasty - bacterial contamination

Microbial colonization of subscapularis tagging sutures in shoulder arthroplasty: a prospective, controlled study

These authors cultured nonabsorbable, braided, subscapularis tagging sutures in 50 consecutive patients undergoing primary shoulder arthroplasty. A similar nonabsorbable, braided suture (control) was placed in a sterile container on the back table, open to the operating room environment.

The subscapularis tagging sutures and control sutures were collected prior to subscapularis tenotomy repair and submitted for aerobic and anaerobic cultures. Cultures were observed for 21 days

A total of 12 of 50 experimental and 16 of 50 control sutures had positive cultures. Staphylococcus epidermidis and Cutibacterium acnes were the 2 most commonly isolated organisms. No significant association between positive subscapularis tagging suture cultures and positive control cultures was found.

Comment: It is difficult to know how to interpret this study in which the "control" cultures were positive at a higher rate than the "experimental" cultures. What then is the meaning of a positive experimental culture?  It surely points out the need for investigators to know the results of control cultures in their OR and lab. From this study, we cannot know if the control cultures were contaminated in the package, in the OR, in transit or in the lab.

Another possible interpretation is that all the instruments, implants and sutures exposed in the OR are at risk for contamination and expose the arthroplasty to infection.

The reporting of cultures as being simply "positive" or "negative" for the different organisms does not  indicate the load (amount) of bacteria in the specimen.

We find that the understanding of culture results is enhanced by the use of semiquantitative methods to assess the load of bacteria in each specimen. 68% of the patients in this study were female; it is known that Cutibacterium skin levels are much higher in males.

Compare the study below in which "control" cultures were found to have very low loads of bacteria. 

Preoperative Skin-Surface Cultures Can Help to Predict the Presence of Propionibacterium in Shoulder Arthroplasty Wounds.

Propionibacterium species are commonly cultured from specimens harvested at the time of revision shoulder arthroplasty. These bacteria reside in normal sebaceous glands, out of reach of surgical skin preparation. The arthroplasty incision transects these structures, which allows Propionibacterium to inoculate the wound and to potentially lead to the formation of a biofilm on the inserted implant. To help identify patients who are at increased risk for wound inoculation, we investigated whether preoperative cultures of the specimens from the unprepared skin surface were predictive of the results of intraoperative cultures of dermal wound-edge specimens obtained immediately after incision of the surgically prepared skin.

Sixty-six patients (mean age, 66.1 ± 9.4 years [range, 37 to 82 years]; 73% male) undergoing primary shoulder arthroplasty had preoperative cultures of the unprepared skin surface and intraoperative cultures of the freshly incised dermis using special culture swabs. For the first 50 patients, a control swab was opened to air during the same time that the dermal specimen was obtained. The results for female and male patients were characterized as the Specimen Propionibacterium Value (SpPV). We then determined the degree to which the results of cultures of the skin surface specimens were predictive of the results of culture of the dermal specimens.

The skin-surface SpPV was ≥1 in 3 (17%) of the 18 female patients and 34 (71%) of the 48 male patients (p < 0.001). The dermal SpPV was ≥1 in 0 (0%) of the 18 female patients and 19 (40%) of the 48 male patients (p < 0.001). None of the control samples had an SpPV of ≥1. The predictive characteristics of a skin-surface SpPV of ≥1 for a dermal SpPV of ≥1 were as follows: sensitivity, 1.00 (95% confidence interval [CI], 0.82 to 1.00); specificity, 0.62 (95% CI, 0.46 to 0.75); positive predictive value, 0.51 (95% CI, 0.34 to 0.68); and negative predictive value, 1.00 (95% CI, 0.88 to 1.00).

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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

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

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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 Propionibacterium prefer suture?

This is an x-ray of a shoulder with pain and stiffness after a prior arthroscopic suture of the labrum to the glenoid in 2007. Note the cystic lesions of the humeral head and glenoid. 

There were no clinical signs of infection. The patient was scheduled for a ream and run procedure. At the procedure antibiotics were withheld until cultures could be obtained. Six sutures were seen to extend from six cystic areas on the glenoid face. The sutures and tissue from the cysts were sent for culture. There was no apparent infection at surgery. His postoperative films are shown below. He was discharged on oral Augmentin and placed on the routine ream and run rehabilitation program.

Ten days after surgery his cultures turned positive for Propionibacterium. He was started on IV Ceftriaxone X 6 weeks and then placed back on Augmentin. He is continuing with his rehabilitation program and making good progress. 

We thought it was interesting that each of the four sutures were culture positive for Propionibacterium whereas neither of the tissue specimens were culture positive at 26 days (see below).

This result suggests that suture may create a 'safe harbor' for the formation of a Propionibacterium-containing biofilm. It also suggests that suture within a wound may be a good specimen to send for culture.

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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'