Whether sutures reduce the graft laceration caused by interference screw in anterior cruciate ligament reconstruction? A biomechanical study in vitro

Abstract

Background Interference screw is commonly used for graft fixation in anterior cruciate ligament (ACL) reconstruction. However, previous studies had reported that the insertion of interference screws significantly caused graft laceration. The purposes of this study were to (1) quantitatively evaluate the graft laceration from one single insertion of PEEK interference screws; and (2) determine whether different types of sutures reduced the graft laceration after one single insertion of interference screws in ACL reconstruction. Methods The in-vitro ACL reconstruction model was created using porcine tibias and bovine extensor digitorum tendons of bovine hind limbs. The ends of grafts were sutured using three different sutures, including the bioabsorbable, Ethibond and ultra-high molecular weight polyethylene (UHMWPE) sutures. Poly-ether-ether-ketone (PEEK) interference screws were used for tibial fixation. This study was divided into five groups (n = 10 in each group): the non-fixed group, the non-sutured group, the absorbable suture group, the Ethibond suture group and the UHMWPE suture group. Biomechanical tests were performed using the mode of pull-to-failure loading tests at 10 mm/min. Tensile stiffness (newtons per millimeter), energy absorbed to failure (in joules) and ultimate load (newtons) were recorded for analysis. Results All prepared tendons and bone specimens showed similar characteristics (length, weight, and pre-tension of the tendons, tibial bone mineral density) among all groups (P > 0.05). The biomechanical tests demonstrated that PEEK interference screws significantly caused the graft laceration (P < 0.05). However, all sutures (the bioabsorbable, Ethibond and UHMWPE sutures) did not reduce the graft laceration in ACL reconstruction (P > 0.05). Conclusions Our biomechanical study suggested that the ultimate failure load of grafts was reduced of approximately 25 % after one single insertion of a PEEK interference screw in ACL reconstruction. Suturing the ends of the grafts using different sutures (absorbable, Ethibond and UHMWPE sutures) did not decrease the graft laceration caused by interference screws.

Outcomes of RigidFix Cross Pin Fixation in Femoral and Tibial Tunnel for Anterior Cruciate Ligament Reconstruction

“…Compression fixation (i.e., interference screw) provides aperture fixation, but the screw often pushes the graft to the side during the screw insertion into the tunnel, reducing the tendon‐bone contact area, and the thread can damage the graft. A study showed that the ultimate failure load of graft was reduced by approximately 25% due to graft laceration by the interference screw 28 . Suspensory fixation allows for circumferential tendon‐bone contact, but its fixation point far away from the joint line can produce a “bungee effect” and a “windshield wiper effect” with cyclic loading 29–31 .…”

“…A study showed that the ultimate failure load of graft was reduced by approximately 25% due to graft laceration by the interference screw. 28 Suspensory fixation allows for circumferential tendon-bone contact, but its fixation point far away from the joint line can produce a "bungee effect" and a "windshield wiper effect" with cyclic loading. [29][30][31] Transtunnel (i.e., RigidFix cross pins) could avoid eccentric fixation and graft injury caused by interference screws, also avoiding the "bungee effect" and "windshield wiper effect" caused by suspensory fixation, which is conducive to graftbone incorporation.…”