Radiographic Landmarks for Identifying the Anterolateral Ligament of the Knee

Purpose: To identify the radiographic position of the origin and insertion of the anterolateral ligament (ALL) of the knee on a lateral radiograph.

Methods: Twelve unpaired, fresh-frozen cadaveric knees were dissected to expose the ALL. The origin and insertion of the ALL on each cadaver were then tagged using 2-mm radiopaque beads. True lateral fluoroscopic views of the knee were then obtained, and the distance from known radiographic landmarks was recorded by 2 reviewers.

Results: The origin of the ALL was found at a distance that is 37.0 ± 9.2% of the total anterior-posterior length of the femoral condyle from the posterior edge as measured along Blumensaat's line. The insertion was located at a distance that is 56.1 ± 6.9% of the total length of the tibial plateau from the posterior edge. The origin of the ALL is 5 mm posterior to a line from the posterior femoral cortex and 9 mm distal to a line along Blumensaat's line. The insertion is 4 mm anterior to the 50% mark of the anterior-posterior width of the tibia, 14 mm distal to the articular surface.

Conclusions: The origin and insertion of the ALL can be accurately identified using intraoperative fluoroscopy.

Clinical relevance: Determining radiographic parameters for the ALL will assist in developing accurate surgical techniques for ALL reconstruction.