Biomechanics of Cervical Disk Replacement: Classifying Arthroplasty Implants

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Biomechanics

Background:

• Cervical disk arthroplasty (CDA) is increasingly used as a motion-preserving alternative to anterior cervical discectomy and fusion (ACDF).
• CDA is indicated for select patients with myelopathy or radiculopathy due to degenerative disk disease.
• Expanding indications necessitate a deeper understanding of cervical kinematics and materials science for implant selection.

Purpose of the Study:

• To classify cervical disk arthroplasty implants based on articulation mode, articulation material, and endplate construction.
• To highlight the importance of translational and rotational degrees of freedom (df) in emulating natural cervical spine movement.
• To emphasize the role of durable, low-friction interfaces and osseous integration for implant performance and stability.

Main Methods:

• Classification of CDA implants based on key design features.
• Analysis of articulation mechanisms, including degrees of freedom (df).
• Evaluation of articulation materials and endplate construction for biocompatibility and osseous integration.

Main Results:

• Cervical disk arthroplasty implants can be categorized by articulation mode, articulation material, and endplate design.
• Incorporation of translational and rotational df enables implants to mimic cervical spine biomechanics.
• Durable, low-friction interfaces and materials promoting osseous integration are crucial for optimal performance and long-term stability.

Conclusions:

• Understanding cervical kinematics and materials science is essential for selecting appropriate cervical disk arthroplasty implants.
• Implant design considerations, including articulation and endplate features, are critical for emulating natural spinal motion and ensuring stability.
• These principles guide the design of current FDA-approved implants and future biomimetic research.