Every year, 1.5 million total knee arthroplasties (TKA) are performed worldwide in patients whose joints have been severely affected by osteoarthritis, rheumatoid arthritis, or trauma, causing intense pain and loss of function. Due to the ageing society, these numbers are expected to have increased six-fold to 3.48 million cases annually by 2030. Even though joint replacement provides satisfactory and durable results for most patients, 20% is thought to still not be satisfied with their artificial joint. To accommodate this dissatisfied population and improve durability of implants even more, several knee systems have been developed over the years. One of the newest models is the ATTUNE knee system (DePuy, Warsaw, Indiana, USA). One of the landmark features is a gradually reducing radius in the geometry of the femoral component, more closely mimicking the anatomical patellofemoral joint and facilitating more natural femoral rollback during flexion. Comparisons of the cemented ATTUNE with previous knee systems show promising results in terms of patellofemoral outcomes, but fail to demonstrate definitive superiority in terms of all patient reported outcomes. Clinical superiority of the ATTUNE tends to abate with longer follow-up, implicating a possible superiority in the short-term recovery and return to activities. There is no follow-up study reporting the results of the uncemented ATTUNE. Moreover, all previously cited studies report better patellofemoral outcomes with patellar resurfacing, making it still unclear whether the implicated superior design changes of the femoral component hold ground without patellar resurfacing.

The primary objective is to report survivorship, complications and patient reported outcome measures associated with the uncemented ATTUNE rotating platform knee system. Secondary objectives are (1) evaluate patient reported (patellofemoral) outcomes (2) assess return to work and sport after TKA (3) translate and validate the Dutch version of the University of California, Los Angeles (UCLA) activity scale and (4) analyse psychologic factors (such as pain catastrophising and coping) and the impact on dissatisfaction following TKA.