[A study of early graft healing after anterior cruciate ligament reconstruction in over-the-top position].

Abstract

Objective: To compare early graft healing between over-the-top (OTT) and anatomic single-bundle (SB) anterior cruciate ligament (ACL) reconstruction.

Methods: A clinical data of 40 patients underwent ACL reconstruction, who admitted between June 2021 and October 2022 and met the selective criteria, was retrospectively analyzed. Among them, 20 patients were treated with OTT reconstruction (OTT group) and 20 with SB reconstruction (SB group). There was no significant difference between groups ( P>0.05) in the gender, age, affected side, disease duration, degree of meniscus injury, body mass index, and preoperative International Knee Documentation Committee (IKDC) score, Lysholm score, pain visual analogue scale (VAS) score, and KT-2000 measurement. At 3, 6, and 12 months, MRI was performed to measure the signal noise quotient (SNQ) of the proximal end, middle, and distal end of the graft in the two groups, as well as at the corner of the graft with lateral femoral condyle and 1 cm around the femoral fixation point in the OTT group, to observe the degree of graft healing. Before operation and at 3, 6, and 12 months, the knee function and pain were evaluated by IKDC score, Lysholm score, and VAS score. Before operation and at 12 months after operation, the KT-2000 measurement was taken to evaluation the knee joint stability.

Results: All operations were successfully completed in both groups and the incisions healed by first intention. All patients were followed up 12-15 months (mean, 12.9 months), with no significant difference in the follow-up time between groups ( P>0.05). After operation, the IKDC score, VAS score, and Lysholm score improved gradually over time in both groups, with significant differences between different time points ( P<0.05). The differences between groups at 3, 6, and 12 months after operation were not significant ( P>0.05). The anterior and posterior stability of the knee joint improved significantly in both groups at 12 months after operation, and the difference in KT-2000 measurements was significant when compared with the preoperative value ( P<0.05), but the difference of pre- and post-operation between groups was not significant ( P>0.05). At 3, 6, and 12 months after operation, MRI showed that the differences in the SNQ of the proximal end and middle of the grafts between the two groups were not significant ( P>0.05), and the SNQ of distal end was significantly higher in the SB group than in the OTT group ( P<0.05). At each time point, grafts in the OTT group had the highest SNQ at the corner and the lowest at the fixation point, and the differences were significant compared to the other sites ( P<0.05). In the two groups, except for the fixation point, the SNQ of the remaining sites were highest at 6 months and lowest at 12 months ( P<0.05). In addition, there were significant differences in SNQ between the different sites of grafts ( P<0.05), and the SNQ was lowest at proximal end and highest at distal end. At last follow-up, the knee grafts in both groups were in good shape and no graft necrosis or loosening of the internal fixation was observed.

Conclusion: The knee joint function and graft healing after OTT reconstruction of ACL are similar to those of SB reconstruction, but it should be noted that the healing at the corner of the graft is slower.