As spine surgery advances toward motion preservation, wear debris remains one of the biggest challenges for implant longevity. A recent Journal of Bone & Joint Surgery study by Dr. Kingsley R. Chin and colleagues compared wear characteristics of the AxioMed® Freedom Lumbar Disc (FLD)—a viscoelastic, one-piece design—with two traditional articulating total disc replacements (TDRs), CHARITÉ and ProDisc-L

AxioMed Wear

Why Wear Matters

Conventional TDRs mimic motion using metal-on-metal or metal-on-polymer interfaces, but this articulation produces submicron wear particles that can trigger inflammation and bone loss (osteolysis). These biologic reactions, driven by macrophage activation and cytokine release, are known causes of implant loosening and revision surgery (Hallab, 2009; Punt et al., 2012).

The Viscoelastic Difference

The AxioMed FLD eliminates mechanical articulation. Instead, its viscoelastic core deforms under load, replicating the spine’s natural shock absorption while minimizing frictional surfaces. The goal: fewer, larger wear particles and lower biologic reactivity.

Study Results

After 30 million simulated motion cycles—equivalent to roughly 80 years of spinal motion—the AxioMed FLD showed:

• Wear rate: 1.70 mg per million cycles (vs. 5.73 mg/MC for ProDisc-L and 0.11 mg/MC for CHARITÉ)

• Particle size: Average 1.9 µm (vs. 0.2 µm and 0.44 µm, respectively)

• Integrity: No structural failures or progressive surface wear observed

Larger particles (>1 µm) are less likely to provoke the inflammatory responses linked to osteolysis (Behl et al., 2013; Ganko et al., 2025).

Clinical Significance

These findings suggest that viscoelastic, one-piece discs may offer a safer and longer-lasting motion-preserving option by reducing biologically active debris. No cases of osteolysis have been reported in clinical experience with the AxioMed device (Rischke et al., 2011; Chin et al., 2017).

Looking Ahead

Further clinical and retrieval studies are warranted, but this research highlights the potential of viscoelastic technology to replicate natural biomechanics while lowering long-term complication risk—a meaningful step toward the next generation of total disc replacement.

References

1. Chin KR et al. Comparative In Vitro Analysis of Wear Particles in a Viscoelastic Disc Versus Two Articulating Total Disc Replacements. J Bone Joint Surg. 2025.

2. Hallab NJ. SAS J. 2009;3(4):143–60.

3. Punt IM et al. Spine. 2012;37(2):150–9.

4. Behl B et al. Biomaterials. 2013;34(14):3547–58.

5. Ganko R et al. iScience. 2025;28(4):112193.

6. Rischke B et al. SAS J. 2011;5(4):97–107.

7. Chin KR et al. J Spine Surg. 2017;3(4):630–40.