Ankle-Brachial Index Is an Effective Screening Tool for Vascular Injury in Schatzker Type-4 to 6 Tibial Plateau Fractures with Symmetric Pulses

Background: Schatzker type-4 to 6 tibial plateau fractures most commonly occur when the distal femur is driven through the proximal tibial articular surface. This mechanism of injury can be equivalent to a knee dislocation and carries an increased risk of vascular injury. Our institution screens all Schatzker type-4 to 6 tibial plateau fractures with symmetric pulses for a vascular injury by measuring the ankle-brachial index (ABI). The purpose of this study was to describe our screening protocol and to determine its effectiveness at identifying vascular injuries.

Methods: Our screening protocol consisted of measuring the ABI of the injured limb for all Schatzker type-4 to 6 tibial plateau fractures that presented with symmetric pulses. An ABI of ≤0.9 prompted a computed tomographic angiogram (CTA) of the injured extremity. We retrospectively reviewed all Schatzker type-4 to 6 tibial plateau fractures from 2006 to 2023 that presented to a single level-I academic trauma center. We collected demographic, fracture, ABI, and vascular injury data and examined the effectiveness of our screening protocol.

Results: We identified 437 Schatzker type-4 to 6 tibial plateau fractures (mean age, 47 years; 59% male). There were 102 (23%) Schatzker type-4 fractures, 4 (1%) type-5 fractures, and 331 (76%) type-6 fractures. Eight fractures (2%) had a concomitant vascular injury; none of the vascular injuries were missed. An ABI of ≤0.9 had a positive predictive value of 0.250, and an ABI of >0.9 had a negative predictive value of 1.000. The sensitivity of the ABI was 1.000, whereas the specificity was 0.056. Thirty-seven fractures were in patients with an ABI of >0.9 at presentation who underwent a CTA of the injured limb for nonorthopaedic indications, with no vascular injuries identified.

Conclusions: The ABI has frequently been cited as a valuable screening tool for vascular injury after a knee dislocation, but its application to Schatzker type-4 to 6 tibial plateau fractures had not yet been described. Our results indicate that this screening protocol is both safe and effective, with no missed vascular injuries over a 17-year period.

Level of evidence: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.