Effect of Lateral Extra-articular Tenodesis on Anterior Cruciate Ligament Graft Incorporation

Abstract

Background: It has been shown that adding lateral extra-articular tenodesis (LET) to standard anterior cruciate ligament (ACL) reconstruction significantly decreases the loads on the ACL composite graft. To date, the possible effect of LET on ACL graft incorporation is not known. Purpose: To compare the incorporation in tibial bone tunnels of a standard quadrupled semitendinosus (ST4) graft to an ST4 graft plus LET at 1 year postoperatively using magnetic resonance imaging (MRI). Study Design: Cohort study; Level of evidence, 3. Methods: A total of 62 patients who underwent ACL reconstruction were enrolled prospectively: 31 received an ST4 graft, and 31 received an ST4 graft plus LET. Graft incorporation was evaluated with MRI at the 1-year follow-up visit. The following parameters were evaluated: signal-to-noise quotient (SNQ), tibial tunnel widening, graft healing, and graft maturity according to the Howell scale. The primary endpoint was the SNQ of the ST4 graft at 1 year postoperatively; this parameter was adjusted because of unequal baseline characteristics between groups. Clinical and functional outcomes as well as incorporation of the graft were analyzed as secondary endpoints. Results: The mean adjusted SNQ was 0.5 ± 2.1 (95% CI, 0.4-4.6) in the ST4 + LET group and 5.9 ± 3.7 (95% CI, 4.7-7.0) in the ST4 group ( P = .0297). The mean tibial tunnel widening was 73.7% ± 42.2% in the ST4 + LET group versus 77.5% ± 46.7% in the ST4 group ( P = .5685). Howell grade I, indicative of better graft maturity, was statistically more frequent in the ST4 + LET group ( P = .0379). No statistically significant difference was seen between groups in terms of graft healing ( P = .1663). The Lysholm score was statistically higher in the ST4 + LET group ( P = .0058). No significant differences were found between groups in terms of the International Knee Documentation Committee subjective score ( P = .2683) or Tegner score ( P = .7428). The mean SNQ of the LET graft at the 1-year follow-up visit was 2.6 ± 4.9. Conclusion: At 1 year postoperatively, the MRI appearance of ACL grafts showed generally better incorporation and maturation when combined with LET.