Polyetheretherketone (PEEK) and carbon-fiber-reinforced PEEK (CFR-PEEK) have been successfully used in the field of orthopedic implants. The polymers PEEK and CFR-PEEK are resistant to fatigue strain and radiologically transparent. These have mechanical properties and are therefore suitable for a range of orthopedic applications. Polymer composites have been proposed for orthopedic applications with the potential of reducing stress-shielding, weight of the implants, wear, and risk of osteolysis. They prevent the release of metal ions by replacing the metal articulating components. The purpose of this review was to investigate the biomechanical effects, technical data, and safety of PEEK and CFR-PEEK biomaterials and evaluate their potential for new innovations in the design of total knee arthroplasty (TKA). This review paper provides an overview with schematics and descriptions, specifically aimed at the development of PEEK and CFR-PEEK for TKA. The appropriate applications for femoral, tibial, and bearing components are highlighted for the optimal design of TKA composite, showing successful biomechanical effects.