Periprosthetic infections of the shoulder - Part 2

Treatment

There is no "standard" treatment for shoulder periprosthetic infections because of the wide variety in clinical presentation (obvious vs stealth), the condition of the patient (septic, frail or otherwise healthy), and the condition of the bone (fragile or strong, cemented, well fixed, or loose implants). 

Thus, the surgeon must customize the treatment to each clinical situation.

Our philosophy is to prioritize preservation of shoulder function over clearance of all bacteria from the surgical field (recognizing that no approach to the treatment of periprosthetic infections can reliably sterilize the surgical field).

Below is a summary of the recent literature and some of our thoughts to aid the surgeon in clinical decision making.

It is essential that every attempt be made to obtain cultures before starting a course of antibiotic therapy, otherwise the chances of identifying the pathogen may be lost. However, in approaching a revision surgery for suspected periprosthetic infection, it is probably ok to administer immediate preoperative antibiotics in that their administration does not seem to alter the results of deep intraoperative cultures.

Debridement, antibiotics, with implant retention DAIR seems particularly applicable in acute obvious infections in shoulders with securely fixed and stable implants (link, link, link, link). Surgeons can consider a partial implant exchange to enable better access for debridement, such as the removal and replacement of a humeral liner in a reverse total shoulder. However, this approach appears to be less effective in resolving the infection than implant exchange, probably because of bacteria-containing biofilms adherent to the implants in established infections (link, link). Some advocate repeating this procedure, the double DAIR.

Complete single stage appears to be the preferred treatment when a periprosthetic infection is suspected, provided that that the existing implants can be removed without excessive damage to the bone of the humerus and glenoid. The single stage is covered in detail in this post. The effectiveness of the single stage - as well as its safety in comparison to the two stage approach - are covered in quite a number of publications (link, link, link, link, link, link, link, link, link, link, link, link, link, link, link, link, link, link, link, link).

Some surgeons advocate the use of a reamer-irrigator-aspirator (RIA) system for cleaning out the medullary canal of long bones, such as the humerus.

The essentials of our approach to the single stage are shown below.

A variation on the single stage, is the Paused Singe Stage (PaSS). As pointed out by Armand Hatzidakis and Jason Hsu  this approach can be useful in the management of a patient who is systemically ill from an obvious infection. It prioritizes debridement while avoiding damaging the remaining bone to an extent that would compromise later reconstruction - this can be referred to as "unresectable hardware". After the debridement, a wound vac is placed with irrigation.

In this case the cultures were overwhelming positive for MSSA

After a few days a functional implant is inserted 

While series of cases treated with PaSS are as yet unavailable, we consider this approach when a conventional single stage cannot be safely performed,

Another variation of the single stage is the functional composite spacer described by Jon Levy. This approach avoids some of the problems associated with the polymethacrylate spacer used in the usual two stage revision (glenoid wear, loosening, difficult in extraction, fracture). After debridement, the surgeon fashions a humeral hemiarthroplasty implant with antibiotic cement coated around the stem.

While large series are at present unavailable, this is a useful approach for reserving a metallic humeral head-glenoid articulation. In the initial reports some patients had good function up to five years after surgery without a second procedure.

Two Stage 

The two stage revision consists of debridement, implant removal and insertion of an antibiotic containing polymethylmethacrylate spacer followed weeks later by removal of the spacer and insertion of the definitive implant. 

A number of articles have been published regarding the two stage treatment of periprosthetic infections. Many emphasize the problems encountered with this approach (link, link, link, link, link. The two stage seems to have an increased risk in patients with high comorbidity index. It has been noted that the microbial spectrum is changed but not eliminated at the second stage (link, link, link). The two stage is more costly than other approaches. Complications are not infrequently encountered with the two stage revision (link, link, link, link, link, link, link, link). The amount of antibiotic eluted from the spacer is limited.

Three Stage

A three stage approach involves a biopsy in between the two stages. 

Spacer for life

Because of the complications associated with the second stage of the two stage approach, some surgeons have reported stopping after the first stage, leaving the spacer in for life (link, link, link, link, link, link)

Resection arthroplasty

Resection of the implants without reimplantation has been reported, but the functional outcomes are poor.

Antibiotic therapy

Surgical treatment of periprosthetic infections is accompanied by antibiotic therapy, usually determined by consultation with experts in infectious disease. 

If preoperative aspiration or biopsy reveals the causative organism, pathogen-specific therapy can be started at the time of surgical revision. If not, the antibiotic choice is made empirically. 

There is evidence supporting the use of topical vancomycin, which may reduce the need for prolonged courses of systemic antibiotics. The SOLARIO trial: SHORT OR LONG ANTIBIOTIC REGIMES IN ORTHOPAEDICS: A RANDOMISED OPEN LABEL MULTI-CENTRE CLINICAL TRIAL found that when local antibiotics are administered, a short regime (≤7 days) of systemic antibiotics was non-inferior to 4 weeks of systemic antibiotics when treating orthopaedic infections. In addition, there were substantially fewer side effects with a short regime (≤7 days) of systemic antibiotics. This approach may also help to prevent the emergence of antibiotic resistance through the overuse of antibiotics as well as saving heath care dollars. 

We commonly use preoperative intravenous ceftriaxone and vancomycin in that they offer coverage for Cutibacterium and coagulase negative staphylococcus (link, link). 

While the use of postoperative intravenous antibiotics administered via a peripherally inserted central catheter (PICC) has been commonly used, the complications and inconvenience have diminished enthusiasm for this approach (link, link). An important clinical trial, Oral versus Intravenous Antibiotics for Bone and Joint Infection, concluded that oral antibiotic therapy was noninferior to intravenous antibiotic therapy when used during the first 6 weeks for complex orthopedic infection, as assessed by treatment failure at 1 year. 

Recognizing that Cutibacterium is the most common organism to cause periprosthetic shoulder infections, oral doxycline seems to offer a balance between safety and efficacy in the initial postoperative treatment until the results of intraoperative cultures become available to guide subsequent therapy. 

The future - phage therapy?

Because of issues with antibiotic resistance, allergies and side effects, there is interest in the application of viral phage therapy in the treatment of periprosthetic infections. 

How effective is treatment?

It is difficult to know whether surgical and medical treatment has successfully eradicated bacteria from an infected shoulder (unless a subsequent surgery is performed with five negative deep cultures). 

There is evidence that the prognosis is worse for individuals with high levels of Cutibacterium on unprepared skin and for shoulders infected with staph aureus

The bottom line

Since the goal of treatment is preserving the comfort and function of the shoulder, perhaps the most practical approach for determining the success of treatment is through the sequential, longitudinal documentation of the patient's self-assessed comfort and the ability to perform individual important shoulder functions. 

Please join us for the AAOS Infection course!!!

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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 ream and run procedure (see this link).
The total shoulder arthroplasty (see 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).