Open knee joint injuries are potentially devastating injuries if not properly diagnosed and treated. Current diagnostic techniques, such as the saline load test (SLT), are based on outdated literature. Diagnosis of traumatic arthrotomies via the presence of intra-articular air on computed tomography (CT) scan has recently been shown to be 100% sensitive and specific to detect these injuries. Additionally, open knee joint injuries have a high rate of associated periarticular fractures (51%). The workhorse open surgical approach to the knee is the medial parapatellar approach; however, arthroscopic irrigation and debridement (I&D) should be considered in the setting of small puncture wounds (e.g., gunshot wounds). Antibiotic therapy following I&D of an open knee joint injury includes 24 to 48 hours of intravenous antibiotics. Oral antibiotic therapy can be administered afterwards for 3 to 5 days if the original injury was grossly contaminated. Ultimately, a unified management algorithm for open knee joint injuries based on current literature should be followed to ensure appropriate diagnosis and treatment of this potentially devastating injury.