The influence of femoral tunnel length on graft rupture after anterior cruciate ligament reconstruction

Abstract

BackgroundFor ACL reconstruction, the minimum length of the femoral tunnel and the flexor tendon graft length needed within the tunnel for proper integration have not been defined. The aim of this study was to assess whether a short tunnel is a risk factor for poor prognosis and re-rupture by comparing the outcomes of patients with short femoral tunnels to those of patients with longer tunnels.Materials and methodsA retrospective observational study of 80 patients who underwent ACL reconstruction using flexor tendons via the medial transportal or transtibial technique was performed. Patients were categorized according to the amount of graft within the tunnel: ≤1.5 versus >1.5 cm; ≤2 versus >2 cm; ≤2.5 versus >2.5 cm; and ≤1.5 versus >2.5 cm. Patients were evaluated 2 years after surgery by performing a physical examination (Lachman, pivot shift and anterior drawer tests), using a KT1000 arthrometer, calculating objective and subjective International Knee Documentation Committee scores, conducting the Lysholm score, and recording re-ruptures.ResultsOf the 80 operated patients, nine were lost to follow-up. Comparative assessment of the patients with different amounts of graft within the tunnel indicated no significant differences in the evaluated outcomes, except for positive Lachman test results, which were more frequent in patients with tunnels with ≤2 cm of graft than in those with tunnels with >2 cm of graft.ConclusionThe amount of graft within the femoral tunnel does not appear to be a risk factor for clinical instability of the knee or re-rupture of the graft. Level of evidence: case series, level IV. Level of evidenceCase series, level IV.

Comparing the Use of Flexible and Rigid Reaming Systems Through an Anteromedial Portal for Femoral Tunnel Creation During Anterior Cruciate Ligament Reconstruction: A Systematic Review

“…This theoretical risk of inadequate tunnel length bears the potential for clinical relevance, especially when deep flexion is unable to be achieved because of a patient’s body habitus, musculature, or intrinsic flexibility. While this suggests a potential technical advantage with the use of AM-FR, a previous study by Guglielmetti et al 10 did not observe a difference in rerupture rates between patients with <1.5 cm versus >2.5 cm of graft within the femoral tunnel. The theoretical risk of insufficient tunnel size has also not been investigated in clinical studies comparing AM-FR and AM-RR to determine the clinical importance of these suggested differences.…”

Biomechanical Effects of Aspect Ratio of the Knee during Outside-In Anterior Cruciate Ligament Reconstruction Surgery

“…The changes in tunnel length among the various ASRs were about 1 mm, and the shortest tunnel length was 27.22 mm. Existing studies found that the BioMed Research International minimum required tunnel length was 25 mm for successful reconstruction surgery [35,39]. Thus, the ASR of the distal femur might not be an essential factor for determining adequate tunnel length.…”

“…For successful ACL reconstruction, many researchers have focused on the optimal tunnel position with tunnelling technique through biomechanical simulations [ 6 , 25 , 34 , 35 ]. However, anatomical characteristics of the knee were not considered in these studies.…”

Flexible reamers create comparable anterior cruciate ligament reconstruction femoral tunnels without the hyperflexion required with rigid reamers: 3D-CT analysis of tunnel morphology in a randomised clinical trial

“…However, although many studies suggest a minimum of 20 mm of soft‐tissue graft within the tunnel, a recent study by Mariscalco et al (for the MOON cohort) showed no difference in patient‐reported outcome measures with hamstring reconstructions (using a suspensory device) in tunnels measuring 14–35 mm [25]. Further, Guglielmatti et al found no increase in graft rupture with short femoral tunnels [9]. Therefore, the benefit of such a small increase may not exist for hamstring reconstructions and is less relevant to other graft choices requiring tunnel length of only 20–25 mm.…”