Morphology of the femoral intercondylar notch.

BACKGROUND: During anterior cruciate ligament reconstruction, proper femoral tunnel placement is important. The purpose of the present study was to characterize the osseous anatomy of the femoral intercondylar notch.
METHODS: We studied the morphology of the femoral intercondylar notch in 200 human femora from skeletally mature donors, with specific attention being paid to the morphology of the ridge on the lateral wall of the intercondylar notch and the posterolateral rim of the intercondylar notch. The distances from the posterolateral rim of the intercondylar notch to the lateral intercondylar ridge and from the posterolateral rim of the intercondylar notch to the inlet of the intercondylar notch (notch depth) were measured at the nine, ten, and eleven o'clock positions for right knees and at the one, two and three o'clock positions for left knees.
RESULTS: The lateral intercondylar ridge was present in 194 femora and absent in six. The mean distance from the posterolateral rim of the intercondylar notch to the lateral intercondylar ridge was 9.0, 11.0, and 12.7 mm at the nine, ten, and eleven o'clock positions in right knees and the one, two, and three o'clock positions in left knees, respectively. We observed three different types of morphology of the posterolateral rim of the intercondylar notch. The morphology of the posterolateral rim of the intercondylar notch was distinct in 183 of 200 specimens. A distinct, straight border (type 1) was seen in 175 femora (87.5%); a distinct, V-shaped border (type 2) was seen in eight (4%); and an indistinct border (type 3) was seen in seventeen (8.5%).
CONCLUSIONS: The morphology of the femoral intercondylar notch varies little. Occasionally, the posterolateral rim of the intercondylar notch is not well-defined. In these knees, accurate placement of commercial femoral tunnel aiming guides may be difficult.