Lyme Prosthetic Joint Infection May Be Underappreciated and Can Be Treated Without Surgery

Abstract

Case:

A 68-year-old woman with a well-functioning total knee replacement presented with signs and symptoms of acute periprosthetic joint infection (PJI). Lyme serology and synovial fluid PCR were performed due to Borrelia burgdorferi. The patient was treated with oral doxycycline, had prompt resolution of symptoms, and remained asymptomatic 2 years later.

Conclusion:

Lyme PJI may be underappreciated as a cause of culture-negative PJI, cannot be diagnosed in routine culture, and can be cured without surgery.

Prosthetic joint infection (periprosthetic joint infection (PJI)) caused by Borrelia burgdorferi, the bacterium that causes Lyme disease, is rarely reported. Although PJI is typically treated surgically, Lyme arthritis of native joints responds well to nonoperative management. Of 7 Lyme PJI cases reported in the literature, 2 were treated nonoperatively. The optimal management of Lyme PJI is unknown. We present a case of Lyme PJI treated successfully without surgery or intravenous antibiotics, to raise awareness of this rarely reported cause of disease, to review its diagnosis, and to suggest that nonoperative treatment may be suitable for this PJI pathogen.

The patient was informed that data concerning the case would be submitted for publication, and she provided consent.

Case Report

A 68-year-old woman living in suburban Connecticut presented to her primary care physician during the month of October with 10 days of right knee pain and swelling, with a temperature of 37.8°C, malaise, and myalgias. Ten years ago, she had undergone uncomplicated right total knee replacement (TKR) and had resumed her usual activities without complication. She had an implant with known recall due to accelerated polymeric wear but had not experienced any issues with the implant before this presentation. She was an avid hiker and had noted multiple ticks on her body over the prior year. She had neither noted any engorged ticks nor any rash consistent with erythema migrans. Her primary care physician examined the patient, obtained laboratory studies, and referred the patient to her orthopedist. Serum Lyme IgG titers were positive, with 10 of 10 IgG bands present on Western blot.

Orthopedic evaluation revealed a large right knee effusion, without radiographic evidence of loosening (Fig. 1). Inflammatory markers were increased (C-reactive protein 36 mg/L and erythrocyte sedimentation rate of 33). Arthrocentesis yielded cloudy fluid with 2319 leukocytes per microliter (71% neutrophils), which failed to grow organisms in aerobic incubation at 5 days or in anaerobic broth conditions at 14 days. Synovial fluid PCR for B. burgdorferi was positive. She was treated with oral doxycycline 100 mg every 12 hours for 28 days. Two weeks after completing doxycycline therapy, her knee pain and effusion had largely dissipated. At 6-month and 2-year follow-ups, the patient reported no residual pain or swelling and had resumed her active lifestyle. Tick bite avoidance strategies, such as hiking with long pants and long socks, using repellent, and avoiding high-risk areas, were reviewed.

Fig. 1.

Right knee radiographs at the time of clinical presentation.

Discussion

PJIs are morbid for patients, frustrating for surgeons, and costly to the medical system. The burden of PJI is significant and growing¹. PJI is generally caused by organisms that persist by forming periprosthetic biofilms, which cannot be sterilized with antimicrobials alone. Opportunities to decrease the surgical morbidity and cost of PJI therapy should be prioritized.

Lyme disease, caused by the bacterial pathogen B. burgdorferi, is spread by Ixodes ticks. Its geographic range, across the northeastern, north-central and mid-Atlantic United States, Canadian provinces, and multiple European countries, has spread over time^2,3. Lyme disease typically is associated with rash and fever but characteristic neurologic, cardiac, and orthopedic manifestations can occur. The most common orthopedic manifestation, by far, is septic arthritis of the knee, which can present days to years after initial infection, which is associated with typical synovial aspirate cell counts of 10,000 to 25,000 leukocytes per microliter, and which is typically treated with oral doxycycline^4,5.

By contrast, Lyme PJI is rarely reported. Seven cases of Lyme PJI have previously been reported in the literature, generally in elderly people, and entirely in TKR (Table I)^6-11. Cases were reported from Connecticut, Pennsylvania, and Virginia; the 2-year follow-up was reported on only one case. Two patients were treated without surgery^6,11. The present case is the first published report of Lyme PJI treated without surgery, with oral doxycycline, and with adequate post-treatment follow-up.

TABLE I.

Eight Reported Cases of Lyme PJI

	Patient	US State	Surgical	Antibiotics	Outcome
Wright 2016	67M	PA	No	IV	Unknown*
Collins 2017	83M	PA	2SE	IV	Success at 12 m
Adrados 2018	89F	CT	I&D	IV	Success at 5 m†
	80F	CT	I&D	IV	Success at 24 m
Ali 2021	81M	PA	I&D	Oral doxycycline	Success at 4 m‡
Crowe 2023	68F	PA	2SE	IV	Success at 12 m
Saar 2024	68M	VA	No	Oral doxycycline	Unknown*
This case	68F	CT	No	Oral doxycycline	Success

^*Minimal reported follow-up after completion of antibiotics.

^†Cardiac death at 5 m, resolution of knee symptoms.

^‡Neurological death at 4 m, resolution of knee symptoms.

CT = Connecticut, F = female, I&D = irrigation and debridement, IV = intravenous, M = male, m = months, PA = Pennsylvania, PJI = periprosthetic joint infection, 2SE = 2-stage exchange, and VA = Virginia.

Diagnosis:

Most patients undergoing diagnostic testing for PJI are not tested for Lyme because the typical PJI tests do not detect it. Borrelia is not culturable using standard clinical microbiology methods, and the commercially available multiplex PCR assay to detect pathogens in synovial fluid does not include this bacterium in their panel¹². The sensitivity of current next-generation molecular pathogen detection assays of synovial fluid for Borrelia is unknown.

Instead, diagnosis of Lyme PJI is most reliably made by a combination of serology and synovial fluid PCR. Two-step serum testing with an enzyme immunoassay screening test, followed by reflex Western Blot testing, diagnoses Lyme disease among those with >5 of 10 IgG bands; almost all patients with Lyme arthritis have >8 bands¹³. Serological testing is insensitive in early infection and can remain positive for years after successful treatment. Synovial fluid PCR for Lyme DNA is commercially available and has been reported to have sensitivity and specificity of 85% and 100%, respectively, in patients with Lyme arthritis¹⁴. However, an isolated positive synovial fluid Lyme PCR in a patient without positive serology often represents a false-positive result¹⁵.

Treatment:

Native joint septic arthritis with pyogenic bacteria (such as Staphylococcus aureus) is generally treated with surgery, whereas Lyme arthritis is not.⁵ B. burgdorferi is a spirochete adapted for survival in arthropod and mammalian hosts and exhibits major structural and biochemical differences with typical human bacterial pathogens^16-18. Unlike staphylococci and other typical pyogenic bacteria, B. burgdorferi’s ability to form biofilm and persist on foreign materials, such as plastic or metal, has not been observed. Immunopathologic studies indicate that it infects perivascular structures and synovium but not cartilage or bone; in contrast to typical pyogenic bacteria, there is no evidence that it produces proteolytic toxins which accelerate joint damage, which may explain the rather indolent course of most Lyme arthritis^19,20.

Conclusion

Lyme PJI is rarely reported and likely underdiagnosed. In endemic areas, Lyme PJI may explain a substantial portion of the 6% to 22% of PJI that are culture negative^21,22. We strongly urge surgeons practicing in Lyme-endemic areas to ask about tick exposure and to order appropriate testing when evaluating for PJI. Nonoperative treatment of Lyme PJI may be adequate.