The "umbrella" technique: reducing hoop stress during suprapatellar nailing in complex proximal tibial fractures.

Background: The surgical management of complex proximal tibia shaft fractures that extend into the joint remains a difficult challenge. The existing body of literature outlines a variety of reduction and fixation strategies, ranging from traditional double-plate constructs, with or without the use of minifragment plates, to fragment-specific plates combined with intramedullary nails, nail-plate combinations, and circular frames. In patients with severely compromised soft tissues, conventional internal fixation techniques can elevate the risk of complications. Nail-plate combinations have emerged as a preferred solution for addressing tibia shaft fractures with proximal intra-articular extension. Nonetheless, these techniques demand meticulous attention to prevent further displacement or splitting of the plateau perimeter during IM nail insertion. In this study, we report a series of three patients presenting with complex proximal tibia plateau fractures with diaphyseal extension. We aim to demonstrate potential benefits of a novel nail-plate combination construct and to provide technical features to this approach using a "hoop stress" plate circling the tibial plateau perimeter prior the insertion of a suprapatellar tibia IM nail.

Patient population and surgical technique: Our series entails three young patients presenting with complex proximal tibia fracture (AO 41-C3) following high-energy trauma. Definitive fixation of these injuries was performed using the "umbrella technique." The approach involves placement of a circumferentially precontoured minifragment plate under the patellar tendon to brace around the anteromedial and anterolateral perimeters of the tibial plateau closing the fracture split. This allows reconstruction of its perimeter, while maintaining and preventing displacement forces during suprapatellar nail insertion. Key clinical and radiological outcome measures included: pain, wound complications, function (standing/walking distance), range of motion, muscle strength, use of crutches, and radiological signs of bone healing, limb alignment and discrepancy, summarized with the modified "HSS knee score".

Results: Our series showed highly favorable results, reporting "Good and Excellent-HSS knee scores" (> 80 points). All fractures healed within a six-month postoperative period, and most importantly no evidence of limb deformity and/or discrepancy was observed. Furthermore, no other secondary clinical complications manifested within the first year of follow-up.

Conclusion: This novel "umbrella technique" should be considered in complex situations where soft tissues around the knee are significantly compromised that can preclude traditional constructs. This technique is useful for protecting the tibial plateau perimeter when selecting nail-plate combination. Our fixation strategy, dubbed the "umbrella technique," entails an anterior minifragment hoop plate to mitigate hoop stress around the plateau facilitating suprapatellar nail insertion without losing the already reconstructed perimeter. This innovative nail-plate combination offers biomechanical advantages to these complex fracture patterns.

Level of evidence: Level IV.