Virtual Conference
Bishnu Prasad Patro

Bishnu Prasad Patro

AIIMS, India

Title: Selection of Interferential screw for fixation of graft in Tibial tunnel during anterior cruciate ligament reconstruction by novel probe test.


Background: Reconstruction of Anterior Cruciate (ACL) Ligament is an established procedure. Graft used for ACL reconstruction are hamstring tendon, bone patellar bone and quadriceps tendon. For the fixation of graft to femur and tibia various methods have been adopted like suspensory loop with button,  interferential screw,  cortical fixation etc. As of now there is no guideline for selection of right diameter of screw, it can be 1mm less, same as that of tunnel diameter or 1-2 mm more than the tunnel diameter. During process of screwing we encountered complications like screw breakage, screw peeling, flattening screw threads etc. Our objective was to find out the right diameter screw for fixation of graft into tibial tunnel.

Methods: We adopted a novel  probe test to assess the bone quality of tibial tunnel using an arthroscope probe and subclassify them into weak, strong and very strong bone. Screw size  was decided as per the probe test either same as tibial tunnel, 1mm more than tibial tunnel or 2mm more than tibial tunnel as per the quality of bone. Length of interferential screw was between 25 mm to 35mm as per tunnel length.

Results: With our probe test complication relating to screw damage decreased from 9.6% (24 of 248 patients) to 0.5% (1 of 187 patients). The need for additional cortical fixation for loose fixation decreased from 36 cases out of 248 (14%) patients to 3 of 187 patients (1.6%).

Conclusion: Probe test is  inexpensive and can be completed in 2 minutes. We conclude that probe test is safe and effective method for selection of interferential screw for fixation of graft into tibial tunnel in ACL reconstruction. 


Bishnu Prasad Patro currently working as head of the department, Department of Orthopaedics, AIIMS, Bhubaneswar with expertise in Arthroscopy of knee and shoulder and arthroplasty of hip, knee and shoulder. He has special interest in designing implants and instruments and published 5 patents. He is guiding 16 post graduate students and trained nearly 30 orthopaedic residents. He performs more than 600 surgeries in a year and by now performed more than 7000 surgeries in arthroscopy, arthroplasty and fractures. He has nearly 20 publications and presently working on artificial intelligence in orthopaedics.