Difference in Graft Maturity of the Reconstructed Anterior Cruciate Ligament 2 Years Postoperatively

Background: Currently, there is an ongoing debate regarding the optimal graft choice between autograft and allograft tendons in reconstruction of the anterior cruciate ligament (ACL). It has been reported that allograft tendons have a slower onset and rate of revascularization compared with autograft tendons. Hypothesis: Allograft tendons might have inferior graft maturity compared with autograft tendons in ACL reconstruction at 2 years postoperatively. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 52 participants with ACL reconstruction were recruited in this study, including 30 using allograft tendons and 22 using autograft tendons. All of them had unilateral ACL reconstruction and were followed up using 3.0-T magnetic resonance imaging (MRI) at least 2 years postoperatively. Clinical examination was performed on the same day when the MRI examination was performed, including subjective functional examinations (International Knee Documentation Committee [IKDC] and Tegner Lysholm Knee Scoring Scale [TLKS]) and physical examinations (anterior drawer test and Lachman test). Four measurements based on MRI were focused on graft orientation (including tibial tunnel position and graft angles), the edematous condition of the graft, intra-articular graft width at different sites, and signal intensity of the ACL graft using the signal/noise quotient (SNQ) from a region of interest analysis. Differences in each measurement were compared between the allograft group and the autograft group. Results: All the participants returned to normal sports activities at the follow-up time point, as all of them acquired full functional strength and stability. There was no significant difference between the autograft and the allograft group with respect to IKDC or TLKS score. The knees in both of the groups were confirmed stable by physical examination before MRI. On MRI measurements, the allograft group displayed no significant difference in graft orientation compared with the autograft group (P > .05). Moreover, there was also no significant difference between allograft group and autograft group in graft width of the distal site (P > .05), middle site (P > .05), and proximal site (P > .05). However, the mean SNQ value of the allograft group was significantly higher than that of the autograft group in the distal site (6.54 ± 6.58 vs 2.98 ± 5.48; P = .0173), the middle site (7.21 ± 6.31 vs 3.56 ± 4.62; P = .0149), and the proximal site (6.61 ± 8.08 vs 2.45 ± 8.12; P = .0018). Conclusion: The allograft group had a significantly higher SNQ value compared with the autograft group in this study, indicating that allograft tendons might have inferior graft maturity than autograft tendons in ACL reconstruction at 2 years postoperatively.