Contemporary Concepts in Cervical Disk Arthroplasty: Implant Design, Constraint, Complications, and Technical Pearls.

» Cervical disk arthroplasty (CDA) is a Food and Drug Administration (FDA)-approved motion-preserving alternative to anterior cervical diskectomy and fusion for 1-level and 2-level degenerative disk diseases, supported by high-level evidence and associated with reduced adjacent segment degeneration and comparable or improved clinical outcomes. » FDA-approved CDA implants differ in biomechanical design, degrees of freedom (DoF), and constraint, affecting motion preservation, segmental control, and long-term kinematics. Devices range from constrained (3 DoF) to semiconstrained and viscoelastic designs (4-6 DoF). Implant articulation and materials impact wear, imaging compatibility, and biomechanical behavior and should be considered during device selection. » Constraint-based classification provides a practical, biomechanics-informed framework for CDA implant selection. Constraint level should be matched to patient pathology. Constrained implants may be preferable in cases of segmental instability, compromised endplate integrity, or poor bone quality. Semiconstrained or viscoelastic devices may offer better outcomes for patients with preserved motion, healthy facets, and high functional demands. » A structured understanding of failure modes is critical for safe and effective CDA use. Complications and failure can result from surgical technique errors (e.g., endplate violation, malposition), biologic response (e.g., osteolysis, heterotopic ossification), or mechanical complications (e.g., implant fracture, subsidence). Technical considerations aid the surgeon in reducing risk of complications.