Total knee arthroplasty using hinge joints: Indications and results.

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Materials science

Background:

• Hinged knee implants, including rotating hinge and pure hinge designs, offer solutions for complex knee conditions.
• Indications for primary total knee arthroplasty (TKA) with hinged implants are specific, addressing ligamentous instability and severe deformities.
• Revision TKA frequently necessitates hinged implants due to factors like infection, aseptic loosening, instability, and bone loss.

Purpose of the Study:

• To delineate the appropriate indications for utilizing rotating hinge or pure hinge implants in both primary and revision total knee arthroplasty (TKA).
• To review the survivorship and complication rates associated with rotating hinge knee implants.
• To provide recommendations for future implant design and surgical technique in TKA.

Main Methods:

• Literature review of studies reporting on the use of rotating hinge and pure hinge implants in primary and revision TKA.
• Analysis of survivorship data and complication rates from existing research.
• Evaluation of factors influencing clinical outcomes, including implant design and surgical technique.

Main Results:

• Primary TKA indications include collateral ligament insufficiency, severe deformities (>20°), significant bone loss, and flexion-extension gap imbalance.
• Revision TKA indications encompass infection, aseptic loosening, instability, and bone loss.
• Ten-year survivorship for rotating hinge knee implants ranges from 51% to 92.5%, with complication rates between 9.2% and 63%.

Conclusions:

• The use of hinged implants in primary TKA should be restricted to carefully selected cases, particularly avoiding them in elderly patients unless strictly indicated.
• Infection and aseptic loosening are the predominant complications associated with rotating hinge knee implants.
• Future advancements should focus on modular designs with shorter stems to simplify revision procedures.