Fusarium Species Fungal Prosthetic Joint Infection of the Proximal Interphalangeal Joint After Silicone Arthroplasty: A Case Report

Abstract

Background:

Prosthetic joint infection (PJI) following proximal interphalangeal joint (PIPJ) arthroplasty is rare, with most reported cases involving bacterial organisms. Fungal PJIs comprise <1% of all PJIs, with Fusarium species an exceptionally uncommon cause, particularly in the upper extremity.

Case Presentation:

A 60-year-old female with a history of rheumatoid arthritis on methotrexate and adalimumab underwent right long finger PIPJ silicone arthroplasty. She presented 12 weeks postoperatively with pain, swelling, and radiographic changes concerning for PJI despite normal inflammatory markers. Implant explantation with debridement was performed, and intraoperative cultures grew Fusarium species. Initial oral voriconazole was insufficient, necessitating readmission for intravenous liposomal amphotericin B and oral posaconazole. Thirty-nine days after completing her 6-month antifungal course, she underwent arthrodesis, which later failed, requiring revision with iliac crest autograft and dorsal plate fixation. At latest follow-up, she remained pain-free with radiographic union and no recurrent infection.

Conclusions:

Based on available literature, this represents the first reported case of Fusarium PJI following silicone arthroplasty of the hand. This underscores the importance of maintaining suspicion for atypical pathogens in immunosuppressed hosts and highlights the complexities managing fungal infections in small joint arthroplasty.

Introduction

Arthritic conditions of the proximal interphalangeal joint (PIPJ) often lead to pain and functional impairment. Initial management involves conservative measures such as nonsteroidal anti-inflammatory drugs (NSAIDs), splinting, therapy, and corticosteroid injections. Patients with PIPJ arthritis who experience persistent or worsening pain and dysfunction despite conservative treatment are indicated for surgical intervention and often benefit from either PIPJ arthroplasty or arthrodesis. ¹ PIPJ arthroplasty is favored in patients desiring preservation of joint motion, with silicone spacers most commonly used.^1,2

Complications following PIPJ arthroplasty are not uncommon and include implant loosening, stiffness, dislocation, and instability, which may ultimately require revision. ² Additionally, as with any prosthetic joint, prosthetic joint infection (PJI) remains a feared complication. While well characterized in large joint arthroplasty, PJIs are infrequently reported following PIPJ arthroplasty. Typically, the offending organism is bacterial in nature with a maximum incidence of 4.08%.^3,4 Fungal PJIs are rare, accounting for <1% of all reported PJIs, however deep fungal infections of the upper extremity carry significant morbidity including risk of joint dysfunction, amputation, and death.^5,6 Given their rarity but significant morbidity one must maintain a high clinical suspicion in immunocompromised patients or those who fail to respond to standard antibiotic therapy.^7,8

Among fungal pathogens, Candida species are the most common and Fusarium species represent an exceptionally rare cause of upper extremity infection, and are particularly rare in PJI. ⁶ These filamentous fungi are associated with opportunistic infections in immunocompromised hosts and are known for causing cutaneous, ocular, and pulmonary disease.^6,9,10 Osteoarticular involvement is uncommon but documented in large joints, often due to hematogenous spread or direct inoculation. ¹⁰

We present the case of a 60-year-old female with rheumatoid arthritis who developed a Fusarium PJI following silicone PIPJ arthroplasty. To our knowledge, based on a review of the available literature, this is the first reported case of Fusarium PJI involving a hand joint and highlights the need for clinical suspicion of atypical pathogens in immunosuppressed patients with delayed postoperative symptoms.

Case Presentation

A 60-year-old right-hand dominant female with a history of non-insulin dependent type II diabetes (A1c 5.1% 2 years prior), seronegative rheumatoid arthritis, and psoriatic arthritis managed with methotrexate and adalimumab presented with chronic right long finger (LF) pain and mechanical symptoms. Prior surgical history included bilateral carpometacarpal (CMC) arthroplasties and endoscopic carpal tunnel releases without complication. On examination, tenderness was localized over the right LF PIPJ, with locking, catching, and tenderness of the A1 pulley of the right long finger. Radiographs showed joint space narrowing, osteophytosis, and subchondral sclerosis of the right LF PIPJ. After 6 months of conservative management, she had refractory pain. Desiring to preserve joint motion, she underwent a silicone PIPJ arthroplasty (Supplemental Material).

She underwent right LF silicone PIPJ arthroplasty with concurrent A1 pulley releases of the index, long, and small fingers. Initial recovery was unremarkable; however, at 12 weeks, radiographs showed ulnar deviation at the PIPJ with signs of osteopenia and early osteolysis (Figure 1A and B). She denied pain at this time and had full range of motion.

Figure 1.

Posteroanterior and lateral radiographs following silicone PIPJ arthroplasty. (A, B) Twelve weeks postoperative. (C, D) Fourteen weeks postoperative.

By 14 weeks, she had new-onset pain, swelling, and decreased range of motion at the right LF PIPJ and presented to clinic for unplanned follow-up appointment. Her white blood cell count (WBC) at that time was 3.3 × 10³ cells/µL, with a C-reactive protein (CRP) of <4.0 mg/L and erythrocyte sedimentation rate (ESR) of 5 mm/hour. Radiographs demonstrated progressive ulnar subluxation of the PIPJ with worsening osteolytic changes along the distal aspect of the proximal phalanx (Figure 1C and D). Diagnosis was unclear and the differential included implant failure, infection, rheumatoid associated inflammatory flare, and aseptic osteolysis.

Due to rapid clinical and radiographic deterioration from 12 to 14 week follow up, she was presumed to have an infection and referred to infectious disease for presurgical evaluation to assess the need for intravenous (IV) antibiotics. Based on the clinical presentation, empiric treatment with daptomycin and ceftriaxone was recommended for a presumed bacterial infection and she was indicated for implant explantation. A peripherally inserted central catheter (PICC) was placed, and the next day she underwent irrigation and debridement with explantation of the silicone implant. Intraoperatively, the implant and surrounding bone were debrided without evidence of purulence, phlegmon or overt osteomyelitis, and specimens were sent for culture (Figure 2A and B).

Figure 2.

Posteroanterior and lateral intraoperative and follow-up images after implant removal for fungal PJI. (A, B) Intraoperative fluoroscopic views during explantation and debridement. (C, D) Follow-up radiographs ~7 months post-explantation.

Although initial histopathologic examination (fungal stain) was negative, intraoperative cultures on post-explantation day 6, grew Fusarium species. Antifungal susceptibility testing revealed the following minimum inhibitory concentrations (MICs): amphotericin B (8 µg/mL), posaconazole (0.125 µg/mL), voriconazole (1 µg/mL), isavuconazole (0.5 µg/mL), and terbinafine (>2 µg/mL). Antibiotics were discontinued, and oral voriconazole was initiated. Due to persistently subtherapeutic voriconazole levels despite reported adherence, lack of clinical improvement over a 2-week course, and antifungal susceptibility testing demonstrating a substantially lower MIC for posaconazole (0.125 µg/mL) compared to voriconazole (1 µg/mL), she was readmitted on post-explantation day 44 for escalation of therapy. In consultation with infectious disease, she was transitioned to IV liposomal amphotericin B—despite its higher MIC of 8 µg/mL—because of its broad-spectrum fungicidal activity and established use in refractory fusariosis, along with oral posaconazole, which demonstrated the most favorable in vitro activity. She was monitored for therapeutic response and discharged on a planned 6-month course of oral posaconazole which was completed.

Following antifungal escalation, inflammatory markers were normal (CRP < 4 mg/L; ESR < 8 mm/hour). However, the patient continued to experience mild pain and functional limitations. Imaging demonstrated persistent erosive and smoldering granulomatous inflammatory changes at the remaining proximal middle phalanx and distal proximal phalanx (Figure 2C and D). In the setting of a presumed resolved fungal PJI after 6 months of posaconazole treatment per infectious disease, and with radiographic signs of residual bone stock deterioration, she was offered and elected to undergo PIPJ arthrodesis.

Twelve months after explantation and 39 days after completing antifungal therapy without signs of recurrence, the patient underwent right LF PIPJ fusion using dorsal distal radius autograft and a 1.5 mm locking T-plate (Medartis AG, Basel, Switzerland), secured with 1.5 mm locking and nonlocking cortical screws (6-8 mm). Cultures obtained at the time of fusion remained negative through the 21-day incubation period. At 6-week follow-up, radiographs showed hardware failure and nonunion at the arthrodesis site, without reported trauma (Figure 3A and B) and she underwent revision fusion with iliac crest autografting and an 8-hole, 2.0 mm reinforced plate (Arthrex, Inc, Naples, FL, USA). At her latest follow-up, 104 days post-revision, she was pain-free with radiographic union and no signs of infection (Figure 3C and D). She has continued to recover without complications or need for additional antifungal therapy.

Figure 3.

Posteroanterior and lateral radiographs demonstrating initial arthrodesis failure and subsequent revision. (A, B) Seven weeks post-initial arthrodesis. (C, D) Six weeks post-revision arthrodesis.

Discussion

PIPJ arthroplasty is a well-established procedure for managing inflammatory and degenerative arthritis of the hand, providing pain relief and functional improvement. ¹ While PJIs in the hand are rare, they are typically bacterial, with Staphylococcus aureus, Streptococcus species, and occasionally Gram negatives, such as Pseudomonas reported. ⁴ We report an unusual case of PIPJ PJI due to Fusarium species in an immunosuppressed patient, necessitating implant explantation, extended antifungal therapy, and ultimately salvage arthrodesis with subsequent revision.

Fungal PJIs comprise <1% of all PJIs and are predominantly attributed to Candida species in large joint arthroplasty. ⁵ However, their incidence is rising—likely driven by rising immunosuppressive factors, widespread use of antibiotics without empiric antifungal therapy, and improved diagnostics. Despite this trend, current guidelines, including those from the Infectious Diseases Society of America (IDSA), offer no specific recommendations for fungal PJIs. ¹¹ This creates diagnostic and therapeutic ambiguity, especially in small joint arthroplasty where evidence is limited.

Diagnosis is frequently delayed, as symptoms may be indolent and laboratory findings nonspecific. ¹² In 1 study of fungal tenosynovitis, the median diagnostic delay was 6 months. ¹³ Our patient developed progressive symptoms by 12 weeks postoperatively, with definitive diagnosis of Fusarium infection established ~4 weeks later. Although she was at an increased risk of fungal infections due to her immunosuppressive therapy (methotrexate, adalimumab, intra-articular corticosteroids) and comorbid diabetes mellitus, fungal infection was not initially suspected. ⁵ Given the rarity of fungal PJIs and the toxicity of antifungal agents, empiric antifungal therapy was deferred. Although the absence of systemic symptoms and normal inflammatory markers (CRP, ESR) and WBC were reassuring, such findings are frequently reported in fungal PJIs and further obscured by her immunosuppressed state. ¹² While culture remains the diagnostic gold standard, fungal PJIs may be culture-negative in up to 46% of cases. ¹⁴ In this case, timely culture positivity enabled organism-specific antifungal management in collaboration with infectious disease specialists.

There have been very few reports of fungal PJI following small joint arthroplasty in the hand, with only 1 previously reported after PIPJ arthroplasty. Dunkley and Leslie described a case of Candida albicans infection in a patient with rheumatoid arthritis following silicone metacarpophalangeal arthroplasty, successfully managed with implant removal and debridement alone, without antifungal therapy. ¹⁵ In contrast, Kobayashi et al reported Aspergillus terreus infection in a PIPJ arthroplasty, treated with implant removal, debridement, and prolonged oral voriconazole therapy. ⁸ In comparison with the only 2 published small-joint fungal PJI cases, our patient exhibited early radiographic changes despite minimal clinical findings and normal inflammatory markers. Radiographic progression preceded symptoms by 2 weeks, underscoring the subtle presentation of Fusarium, the diagnostic challenges in at-risk patients, and the need for early escalation, infectious disease consultation, and individualized antifungal therapy.

In terms of treatment algorithms for fungal PJI, large joint protocols favor 2-stage revision: explantation, debridement, antifungal-loaded spacer placement (often amphotericin B), systemic antifungal therapy (typically oral fluconazole for 6-12 weeks), and delayed reimplantation. ⁵ However, antifungal spacers are rarely used in small joints due to anatomic limitations, technical constraints, and limited data. While fungal PJIs carry higher recurrence rates than bacterial infection, up to 19.4% in large joints, our results coupled with the findings from Kobayashi et al and Dunkley and Leslie suggest that fungal PIPJ PJIs can be managed with single stage explantation and debridement without the need for a spacer. Following single stage explantation, debridement and long-term antifungals the fungal infection was successfully eradicated without need for repeat debridements or a spacer. This reinforces current evidence surrounding single-stage treatment of fungal PJI of the hand.^4,8,15

Given the segmental bone loss and compromised bone quality in both revisions, dorsal plate fixation was selected for the arthrodesis. Dorsal plating offers rigid, multi-planar stability, and effective compression across the fusion site, essential in deficient bone. ¹⁶ Intramedullary (IM) fixation was avoided due to concerns about pathogen tracking into adjacent joints and technical challenges of implant removal in infection, as IM devices spanning joints raise theoretical reinfection risk and biofilm within the canal complicates debridement.^17,18 While a recent study found no significant difference in infection rates across fixation methods, reentry through a prior surgical field and the technical advantages of plate removal supported this approach. ¹⁸

Fusarium PJIs are challenging due to their rarity, virulence, and resistance to antifungals. While most commonly associated with cutaneous or pulmonary infections in immunocompromised hosts, Fusarium can invade deep tissues and poses a challenge in PJIs due to their virulence and resistance to antifungals. ¹⁰ A review of deep upper extremity fungal infections reported a case of Fusarium mycetoma involving the hand, in which the patient presented with osteolytic lesions and was treated with oral ketoconazole. However, no follow-up data were available, and the clinical outcome remained unclear. In the same review, 3 pediatric burn patients developed Fusarium-associated osteomyelitis of the fingers. Two were treated with systemic voriconazole, but 1 ultimately required amputation. A particularly severe case involved a 55-year-old burn patient who developed Fusarium infection of the forearm, culminating in septic shock, and necessitating below-elbow amputation. ⁶ These cases reinforce the importance of maintaining a high index of suspicion for fungal organisms in patients with indolent postoperative infections, especially in those with immunosuppression or autoimmune disease—as in our patient.

Prompt treatment is essential, as fungal PJIs carry high morbidity and significant long-term consequences. Patients often require multiple surgeries, including 2-stage or even 3-stage revisions, and prolonged courses of antifungal therapy.^5,19 Despite these measures, recurrence remains common. A review of 489 large joint fungal PJIs reported a 47.7% recurrence rate after 2-stage revision. Antifungal therapy was continued for an average of 12.8 weeks, and 88% of patients remained on therapy after reimplantation. ⁵ This prolonged, staged process increases surgical burden and can compromise bone integrity, especially in the small joints of the hand. In a series of PIPJ arthroplasties for arthritis, 25% of revised arthroplasties required an additional revision. While pain relief was generally achieved, range of motion declined, particularly in patients who ultimately underwent arthrodesis. ²⁰ These findings highlight the risk of lasting impairment in joint function and mobility, as demonstrated in our patient who required salvage arthrodesis.

Clinical Pearls

This case highlights 3 important considerations for managing rare fungal PJIs in immunosuppressed patients. (1) Early radiographic abnormalities, such as joint malalignment and focal bone loss, may precede overt clinical symptoms by several weeks and should prompt further evaluation in high-risk patients. (2) Optimal management requires close multidisciplinary coordination among orthopedic surgery, infectious disease, microbiology, and pharmacy teams to enable timely diagnosis, targeted antifungal therapy, and appropriate surgical decision-making. (3) In arthrodesis planning for immunocompromised hosts, factors such as immune status, bone quality, and need for durable fixation should guide surgical strategy; in this case, single-stage explantation followed by prolonged antifungal therapy was effective, and revision arthrodesis ultimately achieved union despite initial failure. These points provide practical guidance for surgeons confronted with similar complex presentations. From the patient’s perspective, although she required multiple unplanned procedures due to infection—representing a significant deviation from her expected recovery—they have maintained a satisfactory outcome devoid of infection.