Influence of Mechanical Deformity on Joint Line Reconstruction

Background: Restoration of the joint line is important for an optimal outcome after total knee arthroplasty (TKA). The goal of this study was to analyze the accuracy of joint line reconstruction in conventionally performed TKA. The study evaluates the potential influences of mechanical deformity on joint line restoration. Methods: A total of 115 patients (58.3% female, mean age 72.4 years (52-89)) with 43 valgus and 72 varus knees were reviewed. A total of 36 patients underwent CR-TKA, and 79 underwent PS-TKA. The joint line was measured from the adductor tubercle to the joint line. Results: A total of 106 patients (92.2%) had the joint line restored within four millimeters. The distance increased significantly from preoperative (48.30 ± 6.35 mm) to postoperative 49.03 ± 6.29 mm (p = 0.003). Varus knees showed no significant change (p = 0.313), while valgus knees had a significant elevation (p = 0.0004). Conclusions: In conventional total knee arthroplasty (TKA), the distance from the adductor tubercle to the joint line slightly increased. However, in most patients, the joint line was restored within four millimeters. Valgus knees in particular are at risk for postoperative joint line elevation.