Clinical and Radiographic Results of Attune and PFC Sigma Knee Designs at 2-Year Follow-Up: A Prospective Matched-Pair Analysis

Background: Anterior knee pain (AKP) and/or crepitation are important causes of dissatisfaction after total knee arthroplasty (TKA). Aim of this prospective, matched-pair study was to compare 2 different designs of patellofemoral (ie, trochlear groove) TKA. The Attune knee has an anatomic trochlear groove with a medialized dome patellar component vs the PFC Sigma with a single radius trochlear groove with a domed shaped patella.

Methods: Between January 2010 and December 2014, 100 consecutive Attune TKAs were matched to 100 PFC Sigma TKAs based on age, gender, side, and body mass index. All surgeries were performed via medial parapatellar approach and used cemented, posterior-stabilized implants with patellar resurfacing. Clinical evaluations were assessed using Knee Society Scores (KSS) and a patient-administered questionnaire at 2-year follow-up (range, 1.5-3 years).

Results: Based on the KSS clinical rating system, excellent clinical results were achieved in 89.4% and 90.7% of Attune and PFC Sigma TKAs, respectively. There were no significant differences in the KS pain or function scores. The overall incidence of AKP was significantly lower with the Attune knee compared to that of the PFC Sigma (12.5% vs 25.8%; P = .02). The incidence of hearing or feeling noise was also less with the Attune knee (17.7% vs 30.9%; P = .02). The incidence of painful crepitation was low in both groups (1.0% vs 4.1%) with no significant difference between groups (P = .37). Both groups had similar high satisfaction scores of 8.6 and 8.4 for the Attune and PFC groups, respectively (P = .09).

Conclusion: At 2-year follow-up, there were no differences between the PFC Sigma and Attune knees in KSS or satisfaction. However, the Attune group had a lesser incidence of AKP and crepitation. Further studies should focus on AKP and noise in cruciate-retaining knees.