Aim
Magnetic resonance imaging has been used to evaluate graft integration following anterior cruciate ligament reconstruction (ACLR). The DOSTAR study is a prospective randomized controlled trial (RCT) investigating semitendinosus (ST) versus a dual tendon semitendinosus and gracilis (STG) hamstring autograft. The purpose of the present study is to determine whether magnetic resonance imaging (MRI) analysis identifies differences in graft signal between the two autograft options, and whether signal changes between 6- and 12- months.
Methods
Patients from the DOSTAR trial were invited to take part in this MRI study. Patients underwent anterior cruciate ligament (ACL) reconstruction using either semitendinosus or STG autograft. MRI scans were completed at 6- and 12-months post operatively. The MRI scans were assessed to measure signal intensity ratio (SIR) at several regions of interest. Linear mixed models were used to assess the changes over time for MRI variables. Patient reported outcome measures (PROMS) including the International Knee Documentation Committee (IKDC), Lysholm and Cincinnati scores were documented at 6 and 12 months postoperatively. KT-1000 arthrometer measurements were recorded at 6 and 12 months postoperatively.
Results
A total of 49 patients were recruited into this MRI study, with 38 undergoing MRI at both 6 and 12 months. At 12-months, statistically significant differences were seen on T1 sequences in SIR between the two groups; within the tibial tunnel (3.10 vs 2.07, p
< 0.001), adjacent to the tibial tunnel (2.63 vs 1.88, p = 0.002), in the mid portion of the graft (3.16 vs 2.45, p = 0.009), and within a freehand region encompassing the intra-articular portion of the graft (3.03 vs 2.46, p = 0.018). Differences were not statistically significant adjacent to the femoral tunnel (2.41 vs 2.08, p > 0.05) and within the femoral tunnel (3.09 vs 2.89, p > 0.05). There were no statistically significant differences in any PROMS or in KT-1000 measurements between the ST and STG groups at 6 or 12 months.
Conclusions
Lower SIR was seen in the semitendinosus group. This was observed in T1 and T2 sequences at 6 and 12 months. Graft SIR did not change significantly between 6 and 12 months (p > 0.05).
