Can Valgus Deformity Influence the Evolution of a Total Knee Arthroplasty after 20 Years? A Retrospective Case-Control Study.

Total knee arthroplasty (TKA) is the treatment of choice for knee osteoarthritis. When it is associated with moderate and severe valgus deformities, surgical correction has proven to be more complex. However, there are scarcely any long-term studies assessing this treatment. The aim of this study was to analyze the long-term evolution of a cohort of patients with moderate or severe valgus deformities versus a control group with mild deformities. A total of 1,223 primary TKAs with a mean follow-up of 20.3 years were retrospectively reviewed. A total of 141 TKAs with moderate or severe valgus deformities (hip-knee-ankle [HKA] angle equal to or greater than 190 degrees) were compared with a control group of 1,083 TKAs with mild deformities (HKA between 170 and 190 degrees). Patients were evaluated preoperatively and postoperatively at 1, 3, 5, 8, and 13 years after surgery. The minimum follow-up done was 13 years. In addition, any complications, reinterventions, replacements, and deaths were registered until the end of the follow-up. Preoperatively, the moderate-severe valgus deformities group showed significantly worse Knee Score results than the control group (p < 0.001), while the range of motion was better in the moderate-severe valgus deformities group (p < 0.001). The postoperative outcomes were not statistically different in either group. There were no differences in the complications until the 8th year; however, from this year on and especially from 13 years after surgery, complications increased significantly (p < 0.001) in the moderate-severe valgus deformities group. A long-term observation of a group of TKAs with preoperative moderate or severe valgus deformities, compared with a group with mild deformities, shows that complications increase significantly 13 years after surgery.