Mechanoreceptor analysis on femoral and tibial site remnant of anterior cruciate ligament injury using immunohistochemistry

INTRODUCTIONS: More than 50% of knee ligament injuries are anterior cruciate ligament (ACL) injuries. The injury can lead to instability and osteochondral damage which in turn leads to early osteoarthritis. ACL remnant 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. The number of mechanoreceptors in the ACL remnant 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 ACL remnant during reconstruction. METHODS: This study aims to evaluate semi-quantitatively the expression of mechanoreceptors in ACL remnant in the tibia and femur using immunohistochemistry. From January to April 2021, 10 femoral and 10 tibial remnants was obtained from ACL injury patient who received arthroscopic ACL reconstruction. Both of them were analysed using immunohistochemistry with S100 and NFL antibodies. The type of remnant was recorded and the expression of the mechanoreceptor was observed under the microscope. RESULTS: The most common type of ACL remnant recorded were type 2 (50%), followed by type 1 (40%) and type 4 (10%). There were no significant differences in the expression of mechanoreceptors between femoral remnant and tibial remnant (p = 0.45 and p = 0.134). CONCLUSIONS: No difference in the expression of mechanoreceptors of femoral and tibial ACL remnant. Preservation of both femoral and tibial remnants is important in ACL reconstruction surgery.