Summary

The current randomized study investigated the effect on knee stability of an additional tibial fixation in ACL reconstruction

Abstract

Background

Hamstrings autograft is the most common replacement of the torn anterior cruciate ligament reconstruction. A tendency towards residual anterior translation is often seen as a risk for failure after surgery. Early micro-motion due to graft slippage in the tibial interference screw fixation has been propose as a pathogenesis for this finding. Although biomechanical studies have found an effect of additional tibial fixation on graft slippage – there is a paucity in clinical studies investigating such proposed benefits.

Materials And Methods

Patients undergoing primary anterior cruciate ligament reconstruction using hamstrings autograft, bio-interference tibial fixation and cortical fixed- loop femoral fixation was randomized to standard technique or addition of a tibial suture anchor fixation during surgery. Preoperative assessment and functional scores (thereunder IKDC subjective and Tegner) was recorded – and repeated at the 1 year follow-up evaluation. Instrumented side-to-side translational laxity and pivot shift grading was also included. Students T-testing and Chi-square statistics was used to compare results across groups and over time.

Results

75 patients were randomized to anterior cruciate ligament reconstruction with additional tibial fixation (N=38) and standard reconstruction (N=37). At the 1 year follow-up 91% of patients were available for evaluation. Right knee was treated in 56% of cases and 57% of patients were male. Mean age at surgery was 31.4 (SD 11.7) and time from injury to surgery was mean 3.9 months (SD 4.3). Mean IKDC subjective score improved from 51.4 (SD 15.0) to 69.6 (SD 17.7) in the whole group. There were no differences between the standard and additional fixation groups in side to side translation (1.6 (SD 2.5) versus 1.1 mm (SD 1.9)), IKDC subjective score (72 (SD (16) versus 68 (SD 18)) or incidence of pivot shift (All: P>0.05). When examining for pain from the anterior tibia, in the area of the additional suture anchor, there was no difference in symptoms between groups (P>0.05)

Conclusions

The current study, examining the effect of additional tibial fixation in anterior cruciate ligament reconstruction using hamstrings autograft, found no clear benefit on knee stability at the early 1 year follow-up. A tendency towards less side-to-side translational laxity in the group with additional fixation could indicate a protection from further injuries, and further evaluation of this patient cohort does therefore seem justified. No increase in local symptoms related to the insertion of a suture anchor in the anterior tibia supports this as a safe back-up fixation in selected patients.