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Musculoskeletal Imaging

E2800. Posterolateral Corner of the Knee:An Update and Comprehensive Review

Ashimolowo T,  Dunham G,  Chew F,  Mulcahy H,  Porrino J. University of Washington, Seattle, WA

Address correspondence to G. Dunham (gregordunham@gmail.com)

Background Information: The posterolateral corner (PLC) of the knee is comprised of numerous ligamentous and tendinous structures that provide restraint and stability. This anatomy is complex, and at times controversial. We present a comprehensive review of the normal anatomy and pathology of the PLC. We highlight potential pitfalls of image interpretation and detail what the referring physician needs to know.

Educational Goals/Teaching Points: Isolated injuries to the PLC are rare, and usually occur in conjunction with injury to a cruciate ligament. If unrecognized, PLC injuries can result in posterolateral instability, and may contribute to cruciate ligament graft failure. The anatomy of the PLC is confusing as a result of the number of structures that have been described, variability in nomenclature, and variability in identification of said structures. A recognition of the variations in anatomy and of the limitations of MRI with regards to evaluation of the PLC is necessary in the imaging assessment. Low-grade injuries of the PLC are often managed nonoperatively, while more significant PLC injuries, or those involving the biceps femoris, fibular collateral ligament, and/or popliteus, may require operative intervention.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: As with all ligaments and tendons, the PLC structures are susceptible to variable degrees of tear, ranging from low-grade partial tear, high-grade partial tear, and fully torn. Normal anatomy, anatomic variations, and unique pathologic features to individual structures are described.

Conclusion: Although the anatomy of the PLC can be confusing as a result of the number of structures that have been described, variability in nomenclature, and variability in identification of said structures, MRI still has the ability to provide valuable information with regard to injury within this region.