Abstract
Failure after anterior cruciate ligament (ACL) reconstruction remains a significant clinical challenge, particularly in the revision setting. Among biomechanical factors, increased posterior tibial slope (PTS) is an important factor to consider during the preoperative evaluation of patients undergoing revision ACL reconstruction. A narrative review of the current literature was performed to analyze the biomechanical and clinical role of PTS in ACL graft failure. Emphasis was placed on revision ACL reconstruction, including the biomechanical rationale for slope correction, proposed threshold values, surgical indications, and reported clinical outcomes of slope-reducing osteotomy. A representative clinical case is presented to illustrate the application of these concepts in practice. Biomechanical studies consistently demonstrate that increased PTS leads to higher anterior tibial translation and increased ACL graft forces under axial loading. Clinical evidence supports an association between pathological PTS, most commonly values ≥12°, and increased rates of ACL graft failure in both primary and revision reconstructions. In selected revision cases, slope-reducing proximal tibial osteotomy has been shown to decrease graft loading, improve knee stability, and reduce the risk of recurrent failure. However, available clinical data remain limited and are primarily derived from case series and cohort studies. PTS represents a clinically relevant and potentially modifiable risk factor in revision ACL reconstruction. Slope-reducing osteotomy should be considered as part of a targeted revision strategy in carefully selected patients with pathological PTS, particularly when values exceed 12°. This procedure should not be applied routinely, but rather integrated into a comprehensive revision approach based on individual biomechanical and clinical factors.