Introduction. We present a case of intraosseous foreign body penetration due to knife attack and its emergency service management. Case. Seventeen-year-old patient was admitted to the emergency department with a knife cut over the right knee. In the local wound exploration during the extension position of the knee, deep tissue penetration was not observed. Therefore, the patient was discharged after a primary wound saturation without any radiographic evaluation. During the second admission, the detailed anamnesis revealed that the injury occurred while the knee was in the flexion and the radiographic examination displayed a broken knifepoint in the sagittal plane of the femur's medial patellar region penetrated in the intraosseous tissue. Conclusion. Intraosseous foreign body cases due to the knife attacks are quite rare. There is no algorithm, indicating the necessity of radiographic examination in the stab wounds. Local wound exploration of stab wounds should be done in accordance with the mechanism of injury.