IntroductionGiant cell tumors (GCTs) of the bone are uncommon, locally aggressive neoplasms that primarily affect the epiphyseal regions of long bones, with a predilection for the distal femur or proximal tibia in 55% of cases [1]. Although 80% of GCTs are benign, they have the potential for malignancy and can cause significant bone destruction, leading to pathological fractures in approximately 15% of patients at presentation [1,2]. These tumors are typically solitary, with multifocal occurrences in only 0.5% of cases, and exhibit a female predominance (a female-to-male ratio of 54%) [3]. GCTs most frequently arise in the third decade of life, with 84% occurring in patients aged ≥ 19 years, although fractures are more common in older individuals, reaching 44% in those aged ≥ 55 years [4,5].The presence of a fracture through a GCT at diagnosis often complicates treatment, reducing the efficacy of simple interventions such as curettage and increasing the reliance on prosthetic reconstruction, although it does not elevate the rates of local recurrence or metastasis [6]. The treatment options for GCTs range from intralesional curettage to wide resection, with the choice depending on the tumor extent and structural compromise [7]. In cases involving the distal femur with significant bone loss or fracture, primary total knee arthroplasty (TKA) offers a reconstructive solution to restore function and eradicate tumor tissue [8]. We present the case of a patient who underwent primary TKA following resection of a distal femur GCT and an associated fracture. While effective, this approach introduces challenges, as TKA for GCT is prone to complications such as infection, periprosthetic fractures, and implant loosening, particularly in bone weakened by tumor pathology [9].Revision knee arthroplasty with a long-stem prosthesis was considered, leveraging intramedullary fixation to bypass the compromised bone and restore stability [10]. Although successful in stabilizing the joint, this technique carries risks, including infection and alignment difficulties, and requires careful surgical planning.This case report describes a patient with a distal femoral GCT complicated by a fracture, requiring complex surgery. Implant loosening occurred post-TKA, likely due to biomechanical stress and bone defects, leading to a long-stem revision. We document this rare progression, from GCT fracture to TKA and revision—to enhance the limited literature on the prosthetic management of GCT complications. This case highlights the need for customized surgical approaches and teamwork to tackle oncologic and orthopedic issues, offering insights for clinicians and prompting further research into improving revision techniques for GCT-related arthroplasty failures.