Background: Infections of the foot and ankle require prompt recognition and aggressive treatment to prevent complications such as osteomyelitis, nonunion, and limb-threatening deformity. In rare cases, fungal infections such as Phaeoacremonium venezuelense can lead to chronic osteomyelitis, posing significant reconstructive challenges. When extensive bone loss and joint destruction occur, traditional surgical options may not suffice. Recent advancements in 3D-printed implants have enabled limb salvage procedures in complex foot and ankle cases by offering patient-specific structural solutions. We present the first known case of midfoot reconstruction with a custom 3D-printed titanium cage following chronic P. venezuelense infection.

Case Presentation: A 56-year-old man with psoriatic arthritis initially presented in 2019 with right anterior ankle pain and was diagnosed with anterior tibial tendon tenosynovitis and synovitis. He underwent tendon repair and tenosynovectomy. Nine months later, following palm thorn trauma to the medial foot, the patient developed worsening pain, numbness in the 2nd and 3rd toes, and localized swelling. Subsequent imaging revealed first tarsometatarsal joint arthropathy with reactive bone marrow edema in the medial cuneiform and first metatarsal. Arthrodesis was performed, and intraoperative cultures confirmed P. venezuelense infection. Despite Voriconazole therapy and multiple surgeries, he developed chronic osteomyelitis and nonunion at the arthrodesis site. Amputation was recommended, but declined. Over two years, he underwent numerous debridements, skin grafts, methylmethacrylate spacer placements, and targeted antifungal regimens, including voriconazole, mycamine, amphotericin B, and isavuconazonium. Progressive bone loss necessitated cuboid and lateral column excision, resulting in midfoot-hindfoot discontinuity. After infection eradication was confirmed, a custom 3D-printed titanium cage packed with autograft harvested from the right proximal tibia was implanted. He progressed from non-weight-bearing to full ambulation, remaining pain-free with no sensory impairment or medication use at one-year follow-up.

Discussion: This case report demonstrates the successful use of a custom 3D-printed titanium implant for limb salvage in chronic fungal osteomyelitis of the midfoot. Given the rarity and complexity of persistent P. venezuelense infections, traditional treatment options may not be sufficient, especially in patients with substantial bone deformity. Custom implants enabled an anatomic reconstruction for this patient after extensive bone loss, providing pain relief and restored function. This case supports 3D-printing as a viable option for complex foot and ankle reconstructions when standard interventions for chronic osteomyelitis fail.