Summary

From 6 months to 2 years after anatomical anterior cruciate reconstruction, chronological changes in anterior stability were not observed in reconstruction using bone-patellar tendon bone graft, however, anterior laxity developed over the same period in reconstruction using hamstring graft.

Abstract

Purpose

The commonly utilized autografts for anterior cruciate ligament (ACL) reconstruction are the bone-patellar tendon-bone (BPTB) and the hamstring tendon (HT), but the choice of graft still remains controversial. Clinical outcomes of ACL reconstruction were typically evaluated at specific time-points such as postoperative 1 year or 2 years and similarly, comparisons between BPTB and HT were only performed at specific time-points. Some reports have described postoperative chronological changes in signal intensity of graft on magnetic resonance images. However, few studies have examined post-ACL reconstruction chronological changes in anterior knee stability, as evaluated by tibial anterior translation. The purpose of this study was to characterize the chronological changes in anterior knee stability after anatomical ACL reconstruction and to compare the anterior knee stability achieved with use of BPTB graft with that achieved with use of HT.

Materials And Methods

Eight-two patients who received anatomical ACL reconstruction using a 3D fluoroscopy-based navigation system at our institute between 2013 and 2016 were included in the study. Fifty-nine patients underwent anatomical rectangular tunnel ACL reconstruction using BPTB grafts (Group B) and 23 patients underwent anatomical double-bundle ACL reconstruction using hamstring tendon grafts (Group H). Anterior knee stability was quantitatively assessed using a KneeLax 3 arthrometer at 6 months, 1 year, and 2 years postoperatively. Reconstructed and contralateral knees were assessed with an anterior force of 132 N applied to the proximal tibia at 20° of knee flexion. Side-to-side differences in tibial anterior translation (SDAT) were compared between the reconstructed and contralateral knees. For patient-reported outcome measurement (PROMs), all patients were subjectively evaluated using the Lysholm score and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1 year and 2 years after the surgery.

Results

The postoperative mean SDAT in Group B was 0.3 ± 1.8 mm at 6 months, 0.2 ± 1.6 mm at 1 year, and 0.2 ± 1.6 mm at 2 years; no significant change in SDAT was observed between the three time-points. Postoperative mean SDAT in Group H was 0.1 ± 1.6 mm at 6 months, 0.5 ± 1.3 mm at 1 year, and 1.2 ± 1.3 mm at 2 years; SDAT at two years was significantly greater than that at 6 months (p = 0.01), while no significant difference was observed between the 6-month and 1–year, and between 1-year and 2–year time-points in this respect. At the 2–year time-point, SDAT in Group H was significantly greater than that in Group B; no significant between-group differences were observed at the 6-month and 1-year time-points. PROMs showed no significant differences between 1-year and 2-year, and either between BPTB and HT.

Conclusion

While, no chronological changes in anterior stability were observed after anatomical ACL reconstruction using BPTB graft, anterior laxity developed over the same period ACL reconstruction using HT graft.