Short Femoral In-Tunnel Graft Length Does Not Compromise Graft Healing and Clinical Outcomes After Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction Using Hamstring Autograft

Abstract

Background:

In combined anterior cruciate ligament reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) using hamstring autografts, a femoral in-tunnel graft length (FTGL) of at least 15 mm has traditionally been recommended. However, achieving this length is not always feasible.

Purpose:

To evaluate graft healing and clinical outcomes in patients with an intraoperative FTGL target of 10 to 15 mm, and to investigate whether shorter postoperative magnetic resonance imaging (MRI)–measured FTGL (mFTGL) within this cohort affected outcomes through subgroup analysis.

Study Design:

Case series; Level of evidence: 4

Methods:

The records of patients who underwent primary single-bundle ACLR using a quadrupled semitendinosus autograft and ALLR using a gracilis autograft, with a minimum 2-year follow-up, were retrospectively reviewed. During surgery, the FTGL was intentionally set to fall within the 10- to 15-mm range. Postoperatively, the graft length within the femoral tunnel was measured on postoperative day 2 MRI (mFTGL) and used for analyses. Graft healing was evaluated using 6-month MRI scans: (1) graft incorporation, assessed by the signal-to-noise quotient (SNQ) at the tunnel (SNQ_tunnel), signal intensity at the graft-bone interface, and tunnel widening; and (2) graft ligamentization, assessed by the SNQ of the graft (SNQ_graft) and Howell grade. Clinical outcomes were also assessed. For subgroup analysis, patients were classified into group 1 (mFTGL ≤12.6 mm) and group 2 (mFTGL >12.6 mm).

Results:

A total of 180 knees were consecutively enrolled; 169 completed the 6-month MRI evaluation. The graft failure rate was 3.9%. The mean mFTGL was 12.6 ± 2.6 mm. In subgroup analysis, the femoral SNQ_tunnel difference between the tunnel aperture and proximal site was 0.9 ± 3.3 for group 1 and 2.3 ± 3.9 for group 2 (P = .014). Femoral tunnel widening was 60.1% ± 30.7% for group 1 and 74.3% ± 37.2% for group 2 (P = .008). In multiple regression analysis, mFTGL (β = 3.28; P < .001) and graft diameter (β = −23.86; P < .001) were independently associated with femoral tunnel widening.

Conclusion:

In combined ACLR and ALLR, an intraoperative FTGL target of 10 to 15 mm was clinically acceptable regarding graft failure, graft healing, and clinical outcomes. The subgroup with shorter FTGL showed less femoral tunnel widening.