A New Hinge Prosthesis Offers Ease of Use and the Ability to Retain the Revision Tibial Baseplate.

Total knee arthroplasty (TKA) is a widely practiced surgical procedure, with its efficacy underscored by the increasing number of patients benefiting from it. As primary TKAs rise, the orthopaedic community must prepare for a surge in complex primary and revision knee arthroplasties in the future. While most revisions use non-constrained or semi-constrained prostheses, certain scenarios require a fully constrained (hinge) prosthesis to address major ligamentous and/or bone loss. Over time, hinge designs have evolved, but outcomes with these designs have been mixed. To help address challenges seen with some earlier designs, a new modular revision solution has been designed for both primary and revision surgeries. This system has a new revision baseplate that has compatibilities with varying distal femoral components and introduces an enhanced hinge mechanism. This paper aims to explore the evolution of hinge designs, elaborate on the surgical workflows and intended compatibilities of this new revision hinge system in six different scenarios, and discuss its various potential advantages.

Transient Drude Response Dominates Near-Infrared Pump-Probe Reflectivity in Nodal-Line Semimetals ZrSiS and ZrSiSe.

The ultrafast optical response of nodal-line semimetals ZrSiS and ZrSiSe was studied in the near-infrared using transient reflectivity. The materials exhibit similar responses, characterized by two features, well-resolved in time and energy; the first decays after hundreds of femtoseconds, and the second lasts for nanoseconds. Using Drude-Lorentz fits of the materials' equilibrium reflectance, we show that these are well-represented by a sudden change of the electronic properties (increase of screening or reduction of the plasma frequency) followed by an increase of the Drude scattering rate. This directly connects the transient data to a physical picture in which carriers, after excitation into the conduction band, return to the valence band by sharing excess energy with the phonon bath, resulting in a hot lattice that relaxes through slow diffusive processes. The emerging picture reveals that the sudden electronic reorganization instantaneously modifies the materials' electronic properties on a time scale not compatible with electron-phonon thermalization.