Summary

An Imaging Study of RIGIDfix Cross Pins Used on Tibial Side for Anterior Cruciate Ligament Reconstruction

Abstract

Objective

To explore the surgical procedure of applying RIGIDfix cross pins to tibial side in ACLR and the safe placement area.

Methods

A retrospective study on the post-operative MRI of 62 patients, including 34 males and 28 females at the age of 19-42, with the average age of 28.3 who, from June 2015 to February 2016, received ACLR with their tibial tunnel fixed with RIGIDfix cross pins was conducted. The FODOU-PACS imaging system was adopted to measure the included angle between the plane of the cross pins and the sagittal plane of the tibia, the included angle between the midline of tibial tunnel and horizontal plane and the distance between the midline of two cross pins and the tibial tunnel inlet in each patient after surgery in order to calculate the safe placement area.

Results

Post-operative MRI examination of knee joint was performed to each patient to observe the locations of cross pins. The proximal cross pin in one male patient and two female patients were prominent in front of the tibial insertion of ACL in their joint knees; another proximal cross pin in one female patient was prominent in anterior horn of medial meniscus; the distal cross pin in one female patient failed to fix the graft because the cortex around the cross pin was too thin; the cross pins in one male patient were broken after surgery. As for the other 56 patients, the cross pins were in appropriate locations. According to the statistics, the safe placement area of RIGIDfix cross pins is 21.16 ± 5.26°of the included angle between the plane of the cross pins and the sagittal plane of the tibia, 54.23 ± 3.72°of the included angle between the center line of the tibial tunnel and the horizontal plane of the tibia, and 2.52 ± 0.32 cm of distance between the midline of the two cross pins and the tibial tunnel inlet.

Conclusion

It is safe and effective to fix ACL graft on tibial side with RIGIDfix cross pins. The ideal placement is correlated to the direction and angle of tibial tunnel as well as the position of the cross pins.