Lateral Trochlear Ridge: A Non-Articulating Safe Zone for Anterior-To-Posterior Screw Placement for Capitellum and Trochlea Fractures

Introduction: Distal humerus capitellar shear fractures are rare yet difficult to treat due to the complex fracture patterns and the osteochondral nature of the fragments, limiting optimal screw placement. Current instrumentation options (posteriorly-directed headless screws or retrograde screws) often result in poor fixation in these osteochondral fragments. The use of anterior to posterior screw fixation without countersinking the screw head would potentially improve the fixation strength of this complex fracture pattern. However, this technique is avoided due to concerns of articular impingement and cartilage damage. We set out to determine if there is a safe zone for fixation along the anterior lateral trochlea ridge (aLTR), and to ultimately to map this safe zone to guide screw placement.