Variation in Kaplan fiber insertion to the distal femur and surgical implications: A cadaveric anatomical study comparing Asian and Caucasian knees

Abstract

Background: The iliotibial band together with its attachment to the distal femur, known eponymously as the Kaplan fibers, has been shown to contribute to anterolateral rotatory stability of the knee. However, there remains paucity of data regarding the detailed anatomy of the Kaplan fibers to aid us in anatomical-based surgical reconstruction of these structures. The aim of our study was to identify and compare the presence and quantitative anatomy of the Kaplan fibers in Caucasian and Asian cadavers.

Methods: Twenty paired fresh-frozen Asian and 20 unpaired embalmed Caucasian cadaveric knees were dissected using a standard outside-in technique. The presence, qualitative and quantitative measurements of any distal femoral attachments of the iliotibial band were recorded. Mean values of its dimensions were calculated and compared between the Caucasian and Asian groups.

Results: A consistent supracondylar attachment of the iliotibial band was found in all Caucasian knees and in 19 of 20 Asian knees. The fibers were noted to have two variations with regard to their insertion to the distal femur, either as a single limb or as a double limb attachment, averaging between 30 mm and 40 mm from the lateral femoral epicondyle. No statistically significant difference was noted in dimensions of the fibers between the Caucasian and Asian groups.

Conclusions: The Kaplan fibers are a consistent attachment of the iliotibial band at the distal femur in both Caucasian and Asian knees with two different patterns of insertion. Surgical reconstructions should aim to recreate these attachments to be as anatomically based as possible.

Keywords: Anterior cruciate ligament; Iliotibial band; Iliotibial band tenodesis; Kaplan fibers; Rotatory instability of knee.