PEEK (polyetheretherketone) is a semi-crystalline thermoplastic polymer which, thanks to its excellent mechanical properties, chemical resistance, and high biocompatibility, is widely used in medicine, especially in biomedical engineering. The dynamic development of additive technologies, especially FFF (Fused Filament Fabrication), has enabled the production of personalized medical implants from PEEK, such as skull implants, dental implant components, and orthopedic implants like spine, knee and hip implants. Therefore, the aim of the study was to evaluate the polymer as an alternative material for orthopedic applications and to analyze the effect of annealing and soaking in PBS solution on its strength properties. Heat treatment improves the strength properties of the material. On the other hand, prolonged soaking in PBS solution, which simulates physiological conditions, can lead to changes in the interlayer bonds of the filament layers, which in turn affects the strength properties of the material.