Foreign body penetrating injuries are a relatively common type of injury that has a wide variety of clinical presentations and fates according to the site of injury, depth of penetration, involvement of neurovascular structures, and nature of the foreign body. Hemorrhage is the most common warning sign or complication that may be fatal if it involves large vessels. Penetrating foreign body sequences are not related to their size as related to the site; a small penetrating foreign body in the eye with significance may be more destructive than a large one that does not involve vital structures. A 10-year-old boy was presented to the hospital ER with Rt knee frontal side injury by a retained, penetrating metallic rusty foreign body. Clinical assessment, investigations, extraction, and follow-up were done. Before treating localized injuries, a thorough trauma examination is needed after resuscitation. Treatment includes extended wound exposure, little manipulation, impaled item extraction in the operating room under direct view, sufficient debridement, and antibiotics. Clinicians and radiologists must rule out neurovascular injuries while assessing limbs.