Near-normal ultrasound morphology in quadriceps tendon after anterior cruciate ligament graft harvest.

Abstract

The quadriceps tendon (QT) autograft is increasingly used for anterior cruciate ligament reconstruction (ACLR) due to favourable clinical outcomes. However, the long-term morphological and vascular changes at the QT harvest site remain unclear. This study aimed to evaluate QT morphology and vascularity using ultrasound at least 1 year after ACLR. Thirty-five patients who underwent ACLR with a QT autograft were prospectively evaluated at a mean of 3.4 ± 3.5 years post-operatively. Surgical technique was not standardized with respect to harvest thickness or bone block inclusion. Ultrasound was used to assess anterior-to-posterior (A-P) thickness, medial-to-lateral (M-L) width, cross-sectional area (CSA) and echogenicity of the QT in both knees at 15, 30, 45 and 60 mm proximal to the patella. Superb microvascular imaging (SMI) was employed to evaluate vascularity at the same locations. Comparisons were made between the operated and contralateral sides. A-P thickness was significantly greater in the operated knee at 30 mm (by 0.7 mm, <i>p</i> = 0.01), 45 mm (by 1.1 mm, <i>p</i> < 0.01) and 60 mm (by 1.3 mm, <i>p</i> < 0.01) proximal to the patella. No significant differences were found in M-L width or CSA. Echogenicity was significantly lower in the harvested QT at all levels (<i>p</i> < 0.01), potentially indicating altered tendon quality. Vascularity was observed in 28.6% of patients, primarily within 2 years post-operatively (<i>p</i> = 0.02). A defect at the harvest site was identified in 20% of patients, with a mean size of 16.1% of the total QT CSA. No post-operative QT ruptures or wound complications were reported. QT morphology generally normalized by 3.4 years post-ACLR, although reduced echogenicity persisted, suggesting potential changes in tendon quality. Despite these findings, no clinical complications were observed, supporting the long-term safety of QT autograft harvest for ACLR. Level IV.