Standard Anterior Cruciate Ligament Reconstruction Versus Isolated Single-Bundle Augmentation with Hamstring Autograft

Purpose The purpose of this study was to analyze differences in injury mechanism, preoperative physical examination findings, combined injury pattern, and postoperative clinical results among arthroscopic anterior cruciate ligament (ACL) reconstruction, anteromedial (AM) augmentation, and posterolateral (PL) augmentation with hamstring autograft. We also evaluated the availability of routine magnetic resonance imaging (MRI) for detection of ACL remnant fibers. Methods From January 2005 to May 2007, we analyzed 82 cases of ACL reconstruction, 40 cases of AM augmentation, and 42 cases of PL augmentation. We compared injury mechanism, combined injury pattern, and preoperative and postoperative measurements including range of motion, Lachman test, pivot-shift test, KT-1000 arthrometer test (MEDmetric, San Diego, CA), and International Knee Documentation Committee knee examination form. We also analyzed the availability of the routine coronal view on MRI for detecting ACL remnant fibers. Results A direct injury mechanism was involved more in the AM augmentation group than in the PL augmentation group ( P = .029). MRI diagnosis for the detection of a remnant AM or PL bundle presented excellent intraobserver and interobserver agreement. The incidence of medial meniscus tears was highest in the reconstruction group ( P < .001 v AM augmentation group and P = .003 v PL augmentation group), and it was higher in the PL augmentation group than in the AM augmentation group ( P = .018). The AM augmentation group had a higher incidence of medial collateral ligament injury than the other groups ( P = .006 v reconstruction group and P = .037 v PL augmentation group). The AM augmentation group presented with a lower incidence of a preoperative grade 2 or 3 positive pivot-shift test ( P = .008 v reconstruction group and P = .016 v PL augmentation group), but no difference was found in the other clinical assessments. Conclusions The AM augmentation group was injured more by a direct injury mechanism, and it presented with a greater incidence of medial collateral ligament tear than the PL augmentation group. The incidence of a preoperative grade 2 or 3 positive pivot-shift test was lower in the AM augmentation group than in the other 2 groups. MRI was useful for detection of remnant ACL fibers. Level of Evidence Level III, retrospective comparative study.