Long-term Follow-up of Patellar Nonresurfacing in Total Knee Arthroplasty

Background: We aimed to confirm the long-term effect of patellar nonresurfacing (patellar decompression) in preventing anterior knee pain after total knee arthroplasty (TKA) and to investigate the possible complications. Methods: Among patients who underwent primary TKA after being diagnosed as having advanced osteoarthritis (Kellgren-Lawrence grade 4) at our institution from January 2004 to December 2010, 121 patients who were followed up for more than 7 years were included in this study. Patients who underwent TKA with and without patellar decompression were classified as the study group and control group, respectively. A clinical knee rating score was used to compare the postoperative clinical outcomes between groups. To identify complications after patellar decompression, simple radiographs (weight-bearing anteroposterior and lateral views, patella in 30 degrees and 45 degrees axial views, and whole scanogram) were taken during follow-up. Results: There were no complications such as patellar fracture, osteonecrosis, and subluxation. At 2 years after surgery, the prevalence of anterior knee pain was 12.7% and 18.0% in the study group and control group, respectively (p = 0.42), and the number of patients with patellofemoral osteoarthritis grade II or over was lower in the study group (p = 0.03). At 7 years after surgery, the prevalence of anterior knee pain was 18.3% and 24.0% in the study group and control group, respectively (p = 0.45), and there was no statistically significant intergroup difference in the number of patients with patellofemoral osteoarthritis grade II or over (p = 0.11). Conclusions: Patellar nonresurfacing TKA reduces anterior knee pain in the early postoperative period. The procedure can be considered a relatively safe option with fewer complications; however, its effectiveness appears to decrease over time.