Summary
At 2 years of ACL reconstruction using a ST4 fixed by ASF, the average tibial tunnel enlargement was 13% and no correlation was found between graft maturation and tibial expansion
Abstract
Introduction
Reconstruction of the anterior cruciate ligament (ACL) using a short quadruple semitendinosus (ST4) graft fixed with an adjustable suspensory fixation (ASF) has several advantages but is suspected to generate micromotion, tunnel widening and poor graft maturation. The aim of this study was to evaluate tibial tunnel expansion and graft maturation using a ST4 fixed at both tibial and femoral side with ASF.
Methods
We analyzed retrospectively 149 patients with data collected prospectively at 2 years of follow up with magnetic resonance imaging (MRI). Maturation was analyzed by the Signal-to-Noise Quotient (SNQ) and Howell score at the tibial and articular part of the graft (Ti and Ar Graft). The expansion, the bone-graft contact and the graft volume in the tibial tunnel were calculated by MRI measurement.
Results
At 25.6 months, MRI analysis showed 13% +/-17 expansion of the tibial tunnel, the mean SNQ was 3.75 +/-7.11 for the Ti graft and 1.97 +/-3.49 for the Ar graft, the Howell score of the Ti graft was 41% of grade I, 37 % grade II, 20% grade III, 2% grade IV, the Howell score of the Ar graft was respectively 61, 26, 13 and 1%. The proportion of the graft in contact with the bone wall of the tibial tunnel was 81 % ± 23, the mean filling of the graft volume inside the tibial tunnel was 80%. No significant correlations were found between tibial tunnel expansion and graft maturation at both locations: SNQ Ti graft (p=0.455), SNQ Ar graft (p=0.455), Howell score Ti (p=0.58) and Ar graft (p=0.47). Graft maturation was correlated with the proportion of graft-to-bone contact and graft occupancy volume (p<0,05).
Conclusions
At 2 years of ACL reconstruction using a ST4 fixed by ASF, the average tibial tunnel enlargement was 13% and no correlation was found between graft maturation and tibial expansion. Maturation appears to be correlated with graft-bone contact and graft occupancy volume in the tibial tunnel.