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Diagnose shoulder arthroplasty infections carefully then treat them appropriately
Treatment options include antibiotics, debridement, staged revision, resection arthroplasty and fusion.
The increasing number of traditional and reverse shoulder arthroplasties being performed has started to present clinicians with a variety of surgical challenges.
“We have to manage some very difficult problems in regard to infection after shoulder arthroplasty,” John W. Sperling, MD, MBA, said.
Infection, for example, is a rare complication following shoulder arthroplasty with a reported incidence of up to 4%; however the results can be devastating, he said during the 9th Annual Current Concepts in Joint Replacement Spring Meeting.
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In his presentation Sperling explained how to treat these infections, saying results can vary greatly based on the timing of the shoulder infection.
“It can be very difficult to diagnose an infection, particularly in those patients undergoing revision surgery, because I believe the large majority of patients really don’t present with overt signs of infection, such as sinus track or erythema,” Sperling said.
Radiographs, aspiration
He said two basic principles for tackling infections associated with shoulder arthroplasty are the importance of obtaining serial radiographs and holding culturing for a minimum of 7 days.
Propionibacterium species is usually the predominant organism investigators see associated with post-arthroplasty shoulder infections.
“Serial radiographs, I think, are enormously helpful,” Sperling explained. He said he uses them to identify progressive periprosthetic lucencies, osteolysis and any periosteal new bone formation.
“I like to perform an aspiration on these patients, but the key is they need to be off antibiotics for several weeks prior to the test,” he said.
Sperling recommended keeping cultures a minimum of 7 days which is often enough to be able to catch and detect the organism. If done less frequently, “you may miss this organism.”
There are several tests that can be performed to identify patients at risk of a post-shoulder arthroplasty infection, including a white blood cell count and C-reactive protein and erythrocyte sedimentation rate studies. An analysis Sperling and colleagues at the Mayo Clinic completed on shoulders in 75 patients with positive intraoperative cultures but no clinical signs of infection revealed, “There is no good test to diagnose the patient who will end up having positive cultures.”
However, he recommended antibiotic treatment and observing patients with a positive culture at revision who have a mild infection or what he described as a Type 1 shoulder. For his described Type 2 shoulders, those acutely infected within 30 days of surgery, Sperling suggested debridement and prosthesis retention.
Debridement was also his preferred approach for Type 3 shoulders, those with an acute hematogenous infection, but a well-functioning implant. For chronic infections or Type 4 shoulders, “we think about a two-stage reimplantation,” Sperling said.
He discussed options such as resection arthroplasty and fusion arthrodesis and their indications.
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Images: Sperling JW |
Prostheses removal
Removing components and allowing the joint to “scar in” is critical for resection arthroplasty. At the Mayo Clinic, it improved pain in 13 of 18 patients who regained about 70· active elevation. The technique is also appropriate in patients for whom multiple procedures are contraindicated, Sperling added.
Young active patients may be amenable to shoulder fusion arthrodesis, but doing this correctly can be challenging due to the extensive bone loss that can occur when explanting the original components.
For more information:
- John W. Sperling, MD, MBA, can be reached at the Department of Orthopedic Surgery, Mayo Clinic, 200 First St., SW, 2nd Floor, Rochester, MN 55905; 507-284-4577; e-mail: sperling.john@mayo.edu. He is a consultant to Biomet Orthopedics.
Reference:
- Sperling JW. The infected arthroplasty: “You’re buggin’ me.” Paper #17. Presented at the 9th Annual Current Concepts in Joint Replacement Spring 2008 Meeting. May 18-21, 2008. Las Vegas.