Prosthetic knee instability: prevention and treatment

Abstract

Tibial femoral instability is a common cause of early or late failure of total knee prostheses. Instability may be related to unbalanced ligaments, improper alignment, component malposition, or faulty component design. A patient with an unstable total knee prosthesis may present with pain, giving way, or other mechanical symptoms. The instability may be subtle or may lead to complete dislocation of the tibiofemoral articulation. Several large revision series document instability as the cause of failure and the reason for revision in 10 to 22% of cases. However, detailed analysis of this subset of patients is lacking in these studies. This review examines the causes of total knee instability and presents guidelines for its prevention and treatment.