Contemporary insights into hinged knee arthroplasties : biomechanics, indications, and outcomes in complex primary and revision total knee arthroplasty.

Hinged knee arthroplasty (HKA) serves as a pivotal solution for complex primary and revision total knee arthroplasty, addressing challenges such as ligament insufficiency, instability, and severe bone loss, which in turn leads to ligamentous compromise. Modern hinge designs mitigate historical issues such as aseptic loosening by incorporating advanced features, including enhanced load distribution, tibiofemoral conformity, and improved fixation methods. These innovations provide superior stability and survivorship while accommodating extensive soft-tissue and bony deficiencies. HKA also offers versatility in managing indications such as infection, arthrofibrosis, and neuropathic arthropathy. This review highlights the evolving indications, biomechanical principles, and outcomes of fixed and rotating hinges, emphasizing their indispensable role in advanced knee reconstruction.