Purpose: The purpose of this study was to evaluate the differences in intra-articular pathology, demographic characteristics, and radiographic characteristics of the knee associated with primary anterior cruciate ligament reconstruction (ACLR) versus revision ACLR at the time of initial presentation with either a native anterior cruciate ligament tear or an anterior cruciate ligament graft tear. Secondarily, we aimed to investigate risk factors for concomitant medial and lateral meniscal tears and cartilage injuries at the time of ACLR.
Methods: This was a retrospective review of patients who underwent primary or revision ACLR by a single surgeon. The exclusion criteria were as follows: skeletally immature patients; patients with an intra-articular fracture; patients with an ipsilateral knee infection; or patients who underwent an osteotomy, cartilage restoration procedure, or meniscal transplantation either previously or concomitantly with the ACLR. Detailed patient demographic data, radiographic long-standing alignment, tibial slope, and intraoperative findings including articular cartilage injury grade and meniscus integrity were documented at surgery.
Results: There were 487 patients included in this study (363 with primary ACLR and 124 with revision ACLR). There were no significant differences in age (P 1⁄4 .119), sex (P 1⁄4 .917), body mass index (P 1⁄4 .468), allograft versus autograft reconstruction (P 1⁄4 .916), or prevalence of meniscal tears (P 1⁄4 .142) between the primary and revision groups. Patients who underwent revision ACLR had a significantly increased medial tibial slope (P 1⁄4 .048) and a higher prevalence of chondral defects on both the medial (P < .001) and lateral (P 1⁄4 .003) femoral condyles when compared with primary ACLR patients. Logistic regression showed that a decreased tibial slope was correlated with femoral medial-sided chondral injuries and that varus or valgus coronal-plane malalignment was correlated with lateral meniscal tears in both groups.
Conclusions: The findings of this study show that patients undergoing a revision ACLR have significantly more chondral lesions, as well as higher-grade chondral lesions, at the time of presentation. Furthermore, coronal malalignment and a decreased tibial slope may contribute to injury patterns of the lateral meniscus and medial compartment cartilage, respectively.