A Unique Upside-down Flip-lid Type of Lateral Tibial Plateau Fracture Fragment in a Bicondylar Tibial Plateau Fracture Managed with Dual Plates and Raft Screws.

Introduction: Bicondylar fractures are relatively common, yet those involving an elevated lateral tibial condyle fragment pose a unique challenge due to their atypical presentation. Existing classification systems inadequately describe this elevation, leading to varied terminology like "flip lid" or "reverse-Schatzker type" fractures in the literature.

Case Report: We present a case where the anterolateral osteochondral fragment was elevated and inverted, resulting from a rare mechanism where the left knee was crushed between two vehicles without axial force. This unusual mechanism spared typical signs of condylar widening or depression, with the fragment elevating but remaining submeniscal. This presented a challenge for fixation. The rotated fragment was accessed through an anterolateral approach with submeniscal arthrotomy, reduced, and fixed using raft screws of the lateral locking plate. The medial plateau fracture was stabilized through a posteromedial approach using an antiglide plate. Follow-up at 14 months showed satisfactory outcomes.

Conclusion: Unique injury mechanisms can give rise to distinct fracture types. When X-rays depict an elevated rather than depressed articular surface, suspicion should arise for an elevated, "popped up," or flip lid type fragment. Such cases require a high index of suspicion and a thorough preoperative evaluation using both X-rays and CT scans. Submeniscal arthrotomy is essential to assess meniscus integrity and allow direct visualization of the fracture fragment. Successful outcomes in managing these fractures are based on accurate diagnosis, thorough preoperative planning, and adherence to internal fixation principles.