Suspensory screw fixation does not lead to increased tunnel widening in Anterior Cruciate Ligament reconstruction: a randomized controlled trial comparing interference and suspensory screw fixation.

Abstract

Fixation of Anterior Cruciate Ligament (ACL) grafts inside the tunnels can broadly be achieved by interference screw fixation or suspensory fixation. The aim of this study was to compare the two fixation techniques using Magnetic Resonance Imaging (MRI). This Randomized Controlled Trial allocated patients into two groups: aperture fixation (AF) with interference screw and suspensory screw (SF) fixation with a tape-locking screw construct. The primary outcome was tunnel widening at 1 year. The secondary outcomes were KT-1000 knee laxity and patient reported outcomes by IKDC, Lysholm, KOOS-QoL, VAS and Tegner activity scores. Intraclass and interclass correlation for tunnel widening measurements were obtained and the effects of fixation technique on change in tunnel size was estimated using linear regression modelling. Sixty patients were included and randomized, 29 to AF and 31 to SF technique. Fifty-four patients completed clinical follow-up of whom 50 underwent MRI investigation. The baseline demographics did not differ between the groups. There was no significant difference in mean tibial or femoral aperture widening between the groups. The AF tibial widening was 46 % (SD 28 %) and the SF tibial widening was 38 % (SD 25 %) (P = NS). The AF femoral tunnel widening was 21 % (SD 44 %) compared to 42 % (SD 33 %) in SF (P = NS). The mean ACL graft size for the AF group was 7.4 mm (SD 0.5 mm) and 8.3 mm (SD 0.7 mm) for the SF group. The side-to-side KT-1000 laxity was comparable between the groups. Also, there was no significant difference between in patient reported outcome scores at 1 or 2 years for any of the clinical outcome measures. This study demonstrates no difference in tunnel widening or clinical outcomes between suspensory screw fixation and aperture screw fixation. Clinically, this suggests that neither technique is inferior for surgeon choice, but longer term follow up and repeat imaging is required.