How Effective is Vancomycin for Preventing Infections after TSA?

Tom Wright, MD

Read complete study: The cost effectiveness of vancomycin for preventing infections after shoulder arthroplasty: a break-even analysis

Surgical site infection is one of the most common and expensive post-operative complications to manage in shoulder arthroplasty. The combination of increased methicillin resistance and decreased efficacy of IV cephlasporins, and Propionibacterium acnes  infections , has led shoulder specialists to look for other methods to prophylax against infections in shoulder arthroplasty. Primary shoulder arthroplasty infection rates have been reported from 0-4%, and with revision arthroplasty, the rates are higher, occurring from 4-15% of the time. Although these rates are low, an infection in a shoulder arthroplasty has devastating effects on the patient and is extremely expensive. Surgical site infection accounts for 22% of all health care related infection costs estimated from $1-10 billion annually.

The authors in this article have been using vancomycin powder in the wound bed before closing the surgical site. The authors have looked at the reports from spine surgeries that have shown significant reduction in infection rates when comparing non-vancomycin treatment vs. vancomycin treatment. Based on this information, they have been using vancomycin powder in their shoulder operations since 2013. As with all things in our current health care system, any increase in cost must be justified, and this paper aims at looking at the cost effectiveness of treating patients preemptively with vancomycin powder in the local wound site. They looked at the average cost of 16 patients being treated for infection and quantified the stages of treatment and cost at each stage. The general standard of care for an infected shoulder arthroplasty for patients is as follows:

  1. Arthroscopic biopsy/aspiration
  2. Resection arthroplasty/ Antibiotic impregnated spacer
  3. PICC/Home care for 6 weeks
  4. Repeat biopsy
  5. Revision reverse shoulder arthroplasty

This treatment protocol for these 16 patients averaged $46,744.54 per patient. At the same facility a 1000mg bottle of vancomycin cost $17.15. Based on these data points, the analysis showed that the treatment with vancomycin powder needed to only reduce infection by .04% to be deemed cost effective (break-even).

My practice in a University setting tends to have a large referral base for revisions, which carries a higher infection rate. Because of this high-risk patient population (revision shoulder arthroplasty) and the significant resistance to cephlosporins, it caused me to review the spine literature.

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Can Sufficient Internal Rotation Be Achieved with Bilateral rTSA?

Thomas Wright, MD

Read complete study: Risk of insufficient internal rotation after bilateral reverse shoulder arthroplasty: clinical and patient reported outcome in 57 patients.

This study focused on the effects and risks of bilateral reverse shoulder arthroplasty (rTSA) on internal rotation (IR) in 57 patients. Data was recorded up to two years after the second surgery. The study found that only 15 percent of patients had insufficient IR in both shoulders after 12 months and 5 percent after 24 months. Patients who had insufficient baseline IR in their second shoulder and insufficient IR 12 month post op after their first shoulder had a 100 percent risk of having insufficient IR in both shoulders. The conclusion of this article is a recommendation to use staged bilateral rTSA over the use of a hemiathroplasty. The authors found that the majority of patients would undergo the surgery again, as it does provide benefits, like reduction in pain, regardless of the issues with IR.

Literature Review:

The authors of this study focused on the risks of staged bilateral rTSA on internal rotation. I agree with their concern, as bilateral decreased IR could result in difficulties with toileting. In my practice, I stage my bilateral cases; however the timing is up to the patient. I will proceed with the second surgery no sooner than 12 weeks, but I do not recommend waiting as long as a year. In 2014, we published an article on bilateral rTSA1 in which we found all patients eventually had enough IR to allow toileting with at least one shoulder. I agree with the authors and do not recommend using a hemiarthroplasty in the second shoulder, based on the positive results that we had with rTSA.

Although the article showed a 100 percent failure rate in achieving sufficient IR in the second shoulder when it comes to patients who have both insufficient baseline IR and insufficient IR 12 months post op in their first shoulder, we have not noted that to be a problem.

One example is a 79 year old male with symptomatic cuff tear arthropathy on the right and a failed total shoulder arthroplasty (TSA) on the left due to rotator cuff insufficiency.Because of the predictable nature of performing an rTSA as a primary, the right side was addressed first. At three months post-op he had IR to L5.

Figure_1

79 year old male, cuff tear arthropathy on the right side, 3 months post op

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