Does adjustable-loop femoral cortical suspension loosen after anterior cruciate ligament reconstruction? A retrospective comparative study

Abstract

Background: Recent biomechanical research has suggested that adjustable-loop graft suspension constructs in anterior cruciate ligament (ACL) reconstruction may loosen after deployment. Our objective was to compare short-term knee stability and graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction.

Methods: A consecutive series of 188 patients who underwent primary ACL reconstruction using hamstrings autograft by a single surgeon were divided into two groups; 73 received adjustable-loop (TightRope RT (Arthrex Inc., Naples, FL)) and 115 received fixed-loop (RetroButton (Arthrex Inc., Naples, FL)) femoral cortical suspension. The two groups were compared at six months, one year, and two years postoperatively using KT-1000 arthrometer testing and graft failure rate (revision surgery, grade 2+ Lachman test, any pivot shift, >5mm side-to-side KT-1000 difference).

Results: There was no significant difference between the two groups in maximum side-to-side difference in KT-1000 testing at six months (mean 1.51mm (adjustable-loop group) vs. 1.79mm (fixed-loop group), p=0.23), one year (mean 1.44mm vs. 1.64mm, p=0.48), or two years (mean 1.14mm vs. 1.07mm, p=0.90) postoperatively. There was no significant difference between the two groups in rate of graft failure (10% vs. 11%, p=0.71) or timing of graft failure in affected patients (mean 11.4months vs. 13.8months, p=0.51).

Conclusions: We found no significant difference in postoperative knee stability or graft failure rate between adjustable-loop and fixed-loop femoral cortical suspension in patients undergoing primary ACL reconstruction. Our results suggest that adjustable-loop suspension does not clinically loosen after ACL reconstruction.

Level of evidence: III (retrospective cohort study).

Keywords: ACL reconstruction; Anterior cruciate ligament; Graft failure; Knee stability.