A single-tendon semitendinosus autograft results in lower MRI graft signal compared with a dual tendon autograft. Outcomes from a subgroup of patients undergoing ACL reconstruction in the ‘to be named after blinding// XXBLINDEDXX’ randomised controlled trial

ABSTRACTIntroduction Magnetic resonance imaging has been used to evaluate graft integration following anterior cruciate ligament reconstruction. The ‘to be named after blinding// XXBLINDEDXX' study is a prospective randomised controlled trial 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 ‘to be named after blinding// XXBLINDEDXX' trial were invited to take part in this MRI study. Patients underwent anterior cruciate ligament (ACL) reconstruction using either semitendinosus or semitendinosus and gracilis autograft. MRI scans were completed at 6- and 12-months post operatively. 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 International Knee Documentation Committee (IKDC), Lysholm and Cincinatti scores were documented at 6- and 12- months post operatively. KT-1000 arthrometer measurements were recorded at 6- and 12- months post operatively. 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, p0.05) 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). Level of Evidence Level 2, Subgroup analysis of prospective, single-blinded, randomized controlled trial.