Abstract
Objectives:
To determine the association between loss of extension following primary quadriceps tendon (QT) autograft anterior cruciate ligament reconstruction (ACLR) and QT autograft diameter, while controlling for notch volume.
Methods:
A retrospective review of a consecutive series of patients undergoing primary ACLR with QT autograft between January 2014-December 2021 by seven fellowship-trained orthopaedic surgeons at a single healthcare institution was performed. Exclusion criteria included revision ACLR, multi-ligamentous knee surgery, age <14 years, unavailable preoperative magnetic resonance imaging (MRI), and <6 months follow-up. Loss of extension was defined using the International Knee Documentation Committee (IKDC) criteria for abnormal knee extension (extension deficit >5° compared to the contralateral knee) 3-12 months after ACLR, or any subsequent surgery for an isolated extension deficit. Notch volume was measured by two observers using preoperative MRI scans.
Results:
A total of 500 patients were identified, of which 333 were included (mean age 22.8 ± 7.7 years, 151 (45%) female). The mean follow-up was 1.6 ± 1.3 (range 0.5-9.5) years. The rate of postoperative loss of extension was 11% (n=37), and 70% (n=26/37) of those with loss of extension underwent a subsequent surgery to restore extension. There was no difference in QT autograft diameter (9.5mm vs 9.6mm, P=0.81), notch volume (6.3cm3 vs 6.5cm3, P=0.70), and the ratio between QT autograft diameter and notch volume (1.6 vs 1.6, P=0.75) between patients with and without postoperative loss of extension. No differences were found in preoperative and postoperative extension between patients with a QT autograft diameter ≥10mm and <10mm (P>0.05). Only the inability to achieve terminal extension (0°) at the initial preoperative clinical presentation was associated with postoperative loss of extension on multivariate analysis (OR 2.23 (95% confidence interval 1.10-4.58), P=0.03).
Conclusions:
QT autograft diameter and notch volume were not associated with postoperative loss of extension among patients who underwent primary QT autograft ACLR. The inability to achieve terminal extension (0°) at the initial preoperative presentation increased the risk of postoperative loss of extension by 2.23-fold. Surgeons may consider the lack of terminal extension preoperatively as a risk factor for postoperative loss of extension following QT autograft ACLR rather than increased QT autograft diameter or decreased notch volume.
