Summary
Failure of primary ACLR is more often due at least in part to technical error, while failures of revision ACLR are more often due at least in part to repeat trauma and excessive posterior tibial slope.
Abstract
Introduction
Prior work has primarily investigated factors leading to failure of primary ACL reconstruction, with less work evaluating why revision ACL reconstructions fail. The goal of this study is to compare reasons for failure between these groups. We hypothesize that technical error is more common in failed primary ACL reconstruction and increased posterior tibial slope is more common in failed revision ACL reconstruction.
Methods
A retrospective chart review identified patients who underwent revision for either failed primary ACLR or failed revision ACLR at an academic medical center between 2009 to 2022. Chart and imaging review were undertaken to identify potential contributors to ACLR failure including technical error, recurrent trauma, biological failure, infection, other factors, and elevated posterior tibial slope.
Results
There were 245 patients in the failed primary ACLR group and 61 in the failed revision ACLR group. Failed revision ACLR patients were older (28.5±9.5 vs. 25.7±9.5 years, p=0.040) and that graft being revised more likely to be an allograft in the failed revision group (48% vs. 17%, p<0.001). Failed primary ACLR procedures were more often attributed at least in part to technical errors than failed revision ACLR procedures (68% vs. 31%; p<0.001), with femoral tunnel malposition being the most common error. Failed revision ACLR procedures were more often attributed to biologic failure than failed primary ACLR procedures (8% vs. 2%; p = 0.030) and were more likely to have a posterior tibial slope in excess of 12 degrees (67% vs. 38%; p<0.001).
Conclusions
Failures of primary ACLR procedures were more often attributed at least in part to technical error, while failures of revision ACLR procedures were more often attributed to biologic failure and were more likely to have excessive posterior tibial slope.