Patient satisfaction - A comparison between patient-specific implants and conventional total knee arthroplasty.

Background: Despite recent innovations in total knee arthroplasty, 20% of the patients are not completely satisfied with the clinical results. Regarding patient-specific implants (PSI), the study aims to compare individual and off-the-shelf implant (OSI) total knee arthroplasty (TKA) concerning the postoperative outcome like function and global patient satisfaction.

Methods: In 2013/14 228 patients received a TKA due to primary osteoarthritis with an indication for a bicondylar, cruciate retaining prosthesis. 125 patients received a PSI and 103 an OSI TKA. The outcome after surgery was evaluated retrospectively by two questionnaires and a clinical follow-up examination. The Knee Society Score (KSS) was used to evaluate function. To compare the satisfaction the Knee Injury and Osteoarthrosis Outcome Score (KOOS) and a modified EuroQol (EQ) including five additional questions were used. Finally, 84 patients with PSI and 57 with OSI completed follow-up.

Results: Concerning demographic data, the PSI group showed a significantly younger age, five years on average. The ROM was comparable in both groups. The KSS and the separate function score achieved significantly better results in the PSI group. For subjects with PSI TKA, the global satisfaction showed significant better values.

Conclusions: The significantly higher values in KSS and its function score lead to a better basic daily function in PSI group. In addition, the PSI TKA achieved a higher global patient satisfaction. Nevertheless, both should mainly be assessed in the context of average younger age and the influence of expectations.