# Comparable short‐term anterior knee laxity and extension outcomes following anterior cruciate ligament reconstruction using TightRope II RT, TightRope RT and EndoButton CL: A retrospective matched cohort study

## TL;DR

This study compares short-term knee stability and movement outcomes after ACL surgery using three different fixation devices and finds no significant differences between them.

## Contribution

Demonstrates that TightRope II RT is as effective as TightRope RT and EndoButton CL for short-term ACLR outcomes.

## Key findings

- No significant differences in anterior knee laxity at 6 months between the three fixation methods.
- Low and comparable rates of extension deficit across all groups.
- TightRope II RT is a reliable option for femoral fixation in primary ACLR.

## Abstract

To compare short‐term outcomes in anterior knee laxity and extension deficit 6 months after primary anterior cruciate ligament (ACL) reconstruction (ACLR) with TightRope II RT, TightRope RT or EndoButton CL for femoral fixation.

A retrospective matched cohort study was conducted, including 864 patients (288 per group) who underwent primary ACLR with hamstring tendon autografts at Capio Artro Clinic, Stockholm, Sweden, between 2005 and 2024. Patients were matched 1:1:1 based on age, sex, concomitant medial or lateral meniscal resection, cartilage injury, and time from injury to surgery. Anterior knee laxity was assessed preoperatively and at 6 months postoperatively using the KT‐1000 arthrometer. Extension deficit was defined as >5° from anatomical zero and measured at 6 months using a goniometer.

Preoperative mean side‐to‐side (STS) laxity was 3.8  ± 2.4 mm for TightRope II RT, 3.6  ± 2.4 mm for TightRope RT, and 3.8  ± 3.0 mm for EndoButton CL. At 6 months, STS values were 1.7  ± 1.6 mm (TightRope II RT), 1.8  ± 2.5 mm (TightRope RT), and 2.0  ± 2.3 mm (EndoButton CL). No significant differences were observed between groups at either time point. STS > 5 mm occurred in 1.7% (5/287) of TightRope II RT patients, 5.6% (8/142) with TightRope RT, and 5.8% (15/258) with EndoButton CL, with no significant differences. Extension deficit was observed in 0.4% (1/244), 1.5% (3/203), and 0.8% (2/259), respectively, without significant differences.

TightRope II RT demonstrated comparable short‐term outcomes in anterior knee laxity and extension to both TightRope RT and EndoButton CL. These findings support the use of TightRope II RT as a reliable femoral fixation method in primary ACLR.

Level III, retrospective comparative study.