Comparative Evaluation of Treatment Outcomes of Revision Anterior Cruciate Ligament Reconstruction Using Allograft and Semitendinosus Autograft

<b>Introduction:</b> The number of revision anterior cruciate ligament reconstruction (RACLR) procedures is increasing in proportion to the increase in the number of anterior cruciate ligament reconstruction (ACLR) procedures. Although approximately 50-75% of these procedures can be performed in a single-stage procedure, not all of them can. The choice of graft may influence the results of RACLR. The most commonly mentioned graft materials for RACLR are allografts and autografts. <b>Background/Objectives</b>: The aim of the study was to evaluate the results of single-stage RACLR using a semitendinosus (ST) autograft or allograft and to follow-up and compare the results of both groups after 2 years. <b>Methods</b>: The retrospective cohort study was carried out between 2008 and 2021, during which time 2327 ACLRs were performed. Graft rupture occurred in 198 (8.5%) patients, and 98 (4.2%) patients underwent RACLR. RACLR was performed as a single-stage procedure using a semitendinosus autograft or allograft in 56 patients. The KT-2000, Lachman and axis shift, range of motion, Tegner, Lysholm, KSS, KOOS, and IKDC tests were used to assess outcomes. <b>Results</b>: There were no differences between the groups in terms of age, time of revision after procedure, parameters for the graft (screw diameter, endobutton length, femoral tunnel length) or for the procedure and revision, BMI, or in the time needed for returning to dynamics and training. The groups did not differ in quality of life in any measurements, stiffness, pain function, or sport. Analysis showed higher Lysholm results on the day of treatment in the autograft group than in the allograft group (<i>p</i> = 0.11). The allograft group had higher KSS scores on the day of treatment (<i>p</i> = 0.11) and after 60 months or at the moment of breakup than the autograft group (<i>p</i> = 0.025). <b>Conclusions</b>: Single-stage revision anterior cruciate ligament reconstruction with an autograft and ST provides good knee stability. The results of single-stage revision anterior cruciate ligament treatment using an ST autograft or an ST allograft are similar.