Close-looped graft suturing improves mechanical properties of interference screw fixation in ACL reconstruction

Abstract

Purpose In anterior cruciate ligament reconstruction with looped soft‐tissue grafts, an interference screw is frequently used for tibial fixation. This study compared three alternatives thought to improve the initial mechanical properties of direct bioabsorbable interference screw fixation: suturing the graft to close the loop, adding a supplementary staple, or increasing the oversize of the screw diameter relative to the bone tunnel from 1 to 2 mm. Methods Twenty‐eight porcine tibiae and porcine flexor digitorum profundus tendons were randomized into four testing groups: a base fixation using 10‐mm‐diameter screw with open‐looped graft, base fixation supplemented by an extracortical staple, base fixation but closing the looped graft by suturing its ends, and base fixation but using an 11‐mm screw. Graft and bone tunnel diameters were 9 mm in all specimens. Constructs were subjected to cyclic tensile load and finally pulled to failure to determine their structural properties. Results The main mode of failure in all groups was pull‐out of tendon strands after slippage past the screw. The sutured graft group displayed significantly lower residual displacement (mean value reduction: 47–67 %) and higher yield load (mean value increase: 38–54 %) than any alternative tested. No other statistical differences were found. Conclusions Suturing a soft‐tissue graft to form a closed loop enhanced the initial mechanical properties of tibial fixation with a bioabsorbable interference screw in anterior cruciate ligament reconstructions using a porcine model, and thus, this may be an efficient means to help in reducing post‐operative laxity and early clinical failure. No mechanical improvement was observed for an open‐looped tendon graft by adding an extracortical staple to supplement the screw fixation or by increasing the oversize of the screw to tunnel diameter from 1 to 2 mm.

Anatomic Outside-In Anterior Cruciate Ligament Reconstruction Using a Suspension Device for Femoral Fixation

“…5 We believe that the technique described is both easy to perform and highly feasible, reducing the risk of complications and technical problems that other systems entail. Table 1.…”

“…Fixation resistance has been proved to be increased if both ends of the graft are sutured beforehand. 5 The technique outlined in this report is designed to eliminate, or at the very least minimize, the risk of these complications arising, thus making reconstruction easier to carry out and achievable without specialized surgical instruments. It involves the use of the outsidein technique to create both the femoral and tibial tunnels, a procedure that can be performed with any of the ACL guides habitually used for the tibial tunnel, the only condition being that the guide must be adjustable to at least 80 .…”

Biomechanical analysis of a double fixation method for tendon graft in porcine tibia – using an interference screw plus staple

“…Therefore, the screw as an isolated fixation device may have been sufficient to bring the tendon to its plastic deformation, making additional attachments irrelevant from the mechanical standpoint. 10 , 12 However, another study observed a greater clinical stability in the group with additional fixation with staples two years after surgery. 9 …”

“…The staple can be used as a supplement to the interference screw, but only a few studies in the literature have assessed the mechanical behavior of the supplementary fixation with staples in the tibia. 7 , 9 , 10 …”

Posterior Cruciate Ligament Reconstruction With Hamstring Tendons Using a Suspensory Device for Tibial Fixation and Interference Screw for Femoral Fixation

“…form a closed loop. 5 A suspension device (G-Lok) is placed in position beforehand with a loop as long as necessary, depending on the graft's and tibial tunnel's lengths. This is accompanied by a further device of greater length (G-Lok XL; Stryker) to facilitate cortical fixation once the whole of the tunnel has been created with a diameter identical to that of the graft (Fig 3).…”