Introduction: More than 50% of knee ligament injuries are Anterior Cruciate Ligament (ACL) injuries. These injuries are often accompanied by injuries to the MCL and LCL or medial meniscus. The injuries can lead to instability and osteochondral damage which in turn leads to early osteoarthritis. Remnant ACL contains sensory nerve cells and mechanoreceptors which are useful for reinnervation of the graft and maintaining the knee stability. However, ACL remnant preservation can interfere the visualization during surgery and also can cause cyclop’s lesion. So, the number of mechanoreceptors in the remnant ACL of the tibia and femur have to be determined to help the surgeon get better visualization and at the same time preserve the mechanoreceptors in the remnant ACL during reconstruction.

Methods: This study aims to detect semiquantitatively mechanoreceptors in remnant ACLs in the tibia and femur using immunohistochemistry. From January to December 2021, 10 femoral and 10 tibial remnant was obtained from ACL injury patient who undergone arthroscopic ACL reconstruction. Both of them were analysed using immunohistochemistry with S100 and NFL antibody. The type of remnant were recorded and the quantity of mechanoreceptor were observed under the light microscope.

Results: The most of the remnant recorded are type 1 (40%). There were no significant differences in the number of mechanoreceptors between femoral remnant and tibial remnant (p=0.449 and p=0.134). The results suggested that the remaining mechanoreceptor in the remnant ACL survive a long time and no obvious change.

Conclusion: Because of no difference between femoral and tibial remnant, the surgeon can still preserve the mechanoreceptors in the remnant while expanding and clearing the visualization during operation.