Total Knee Arthroplasty in prior anterior cruciate ligament reconstruction: how to manage a peculiar challenge in the robotic era

Background: Patients with a history of anterior cruciate ligament reconstruction (ACLR) increasingly present with secondary knee osteoarthritis. These cases often exhibit unique anatomical features, such as increased posterior tibial slope and coronal plane deformities, which complicate total knee arthroplasty (TKA) and are associated with higher complication rates and longer operative times compared to primary osteoarthritis.

Objective: This article evaluates the technical challenges of TKA following prior ACLR and assesses the efficacy of imageless robotic-assisted surgery and personalized alignment strategies in managing these complex cases.

Key Points: Clinical data from a prospective study of 70 patients demonstrate that the ACLR group had significantly steeper preoperative tibial slopes (12.55° vs. 9.42°) and higher rates of central pivot laxity (54.3%) than controls. Intraoperatively, the ACLR group required longer surgical durations, more frequent tibial recuts (20% vs. 2.8%), and a lower utilization of medial congruent liners. Despite these baseline anatomical and functional disparities, the use of an imageless robotic system facilitated precise implant positioning and soft tissue balancing. At a mean follow-up of over three years, postoperative outcomes including Knee Society Scores and WOMAC indices were comparable between groups, with the exception of a residual reduction in maximum flexion in the ACLR cohort.

Conclusion: Robotic-assisted TKA using a personalized alignment approach effectively mitigates the technical difficulties associated with post-ACLR altered anatomy. This technology enables intraoperative adjustments to constraint levels and soft tissue balancing, resulting in clinical outcomes and complication rates equivalent to those of primary TKA.