According to the study, researchers explained the most common mechanism of total knee arthroplasty (TKA) failures included aseptic loosening, instability and malalignment

With total knee arthroplasty (TKA) operations being performed and patients’ lifespan increasing, there is an ever-growing number of this operation in the United States. Based on 2010 data, an estimated 4.7 million individuals (3.0 million females, 1.7 million males) are living in the United States with a total knee.

Additionally as the average age for TKA is becoming younger and living longer, the total number of revisions performed increases. By 2020, it is estimated 1.3 million TKAs will be presented along with 127000 changes. Also, with focus on value-based healthcare, and government bundled payment initiatives, it is imperative to understand why total knees fail.

In 1982, Rand et al. reported 227 knees undergoing revision in the Mayo Clinic registry data from 1970 to 1980. Within those revisions, the average time from initial arthroplasty to failure was 2.7 years with loosening (34.9%) being the major cause of TKA failure.

Instability and malalignment were second and third at 16.7% and 14.8%, respectively. Component malposition, periprosthetic fracture and patellofemoral complications were all around 5%.

Periprosthetic joint infections were reported to be exceedingly rare at 0.2% (but this will become the leading cause of revision). The dominance of loosening was likely because of high use of the older hinge prosthesis designs such as the Guepar that resulted in increased interface stresses and loosening.

As polyethene production improved, modes of failure from polyethene wear and subsequent osteolysis became less prevalent. Newer longitudinal studies report that infection has become the primary acute cause of failure with loosening and instability remaining as the overall most significant reasons for revision. Clinical database and worldwide national registries confirm these reports. 

With increasing number of revision TKAs being performed, tighter control on healthcare costs and value-based care may occur. Surgeons are tasked with the responsibility to avoid risk factors for change TKA.

Newer longitudinal studies report that infection has become the primary acute cause of failure with loosening and instability remaining as the overall greatest reasons for revision. Knowledge of total knee arthroplasty failure mechanisms allows the arthroplasty surgeon to be aware of individual risk factors, and to strategise management for each patient to optimize their care.

These longitudinal studies summarise that infection has become the primary acute cause of failure with loosening and instability remaining as the overall most excellent reasons for revision Table. The researchers’ conclusions are that most failures can be avoided by improvements in technique and design.