Total knee arthroplasty with modular rotating-platform hinge.

Third-generation modular rotating hinged knee systems are now widely available. The S-ROM rotating hinge features slotted and splined stems for torsional stability, and metaphyseal filling and loading sleeves for the bony defects encountered in revision total knee arthroplasty (TKA). Primary indications for a hinge include medial or lateral collateral loss, massive bone loss, and metaphysis and cortical shell, which includes collateral origins or insertions, and severe flexion gap imbalance requiring a link system for stability. Indications for a hinge in primary TKA include patients with neuromuscular deficits such as polio or flail knee, who require the hyperextension stop. Reported midterm results are excellent with no mechanical failures and positive bone remodeling in 65 patients.