Lyme Disease Mimics Prosthetic Joint Infection After Knee Replacement

Lyme disease can mimic prosthetic joint infection, leading to unnecessary surgery and delayed diagnosis.

An 83-year-old man from Pennsylvania was admitted with knee pain, erythema, and fever for 3 days. Examination revealed a moderate effusion and limited range of motion in a knee that had undergone total replacement 6 years earlier.

Although culture tests were negative, the patient met Musculoskeletal Infection Society criteria for periprosthetic joint infection (PJI).

Surgery Based on Suspected Infection

The prosthetic knee was removed, and the patient underwent resection arthroplasty with placement of an antibiotic spacer.

He was treated with 6 weeks of intravenous antibiotics for presumed infection.

Lyme Disease Diagnosis Confirmed

Postoperatively, testing revealed Lyme disease. Both Lyme antibody testing and synovial fluid PCR were positive.

Lyme IgG testing showed 8 of 10 significant bands, confirming disseminated infection.

The diagnosis was revised to Lyme disease.

Recovery After Targeted Treatment

The patient improved following 2 weeks of oral doxycycline and 4 weeks of intravenous ceftriaxone.

He later underwent successful reimplantation of the knee prosthesis.

Clinical Implications

This case highlights the importance of considering Lyme arthritis in patients with suspected culture-negative prosthetic joint infections.

Early recognition of Lyme disease may prevent unnecessary surgery and reduce exposure to prolonged broad-spectrum antibiotics.

Clinicians in endemic regions should include Lyme disease in the differential diagnosis of unexplained joint inflammation, particularly when standard cultures are negative.

Clinical Takeaway

Lyme disease can mimic prosthetic joint infection and should be considered in culture-negative cases.

References

Collins KA, Gotoff JR, Ghanem ES. Lyme Disease: A Potential Source for Culture-negative Prosthetic Joint Infection. J Am Acad Orthop Surg Glob Res Rev. 2017;1(5):e023.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention