Radiographic Landmarks for Identifying the Anterolateral Ligament of the Knee

PurposeTo identify the radiographic position of the origin and insertion of the anterolateral ligament (ALL) of the knee on a lateral radiograph.MethodsTwelve 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.ResultsThe 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.ConclusionsThe origin and insertion of the ALL can be accurately identified using intraoperative fluoroscopy.Clinical RelevanceDetermining radiographic parameters for the ALL will assist in developing accurate surgical techniques for ALL reconstruction.