Exponent’s biomechanics laboratory facilities in Philadelphia have the capabilities to perform wear and fatigue simulations for total disc replacements, nucleus replacements, and posterior dynamic stabilization spine implants. In addition to setting up the wear simulations to comply with ISO 18192 or ASTM F2423 standards for regulatory submission, we can also perform the gravimetric wear assessments and evaluate the wear surfaces. We have extensive expertise in evaluating wear mechanisms in retrieved spine implants, including total disc replacements, posterior dynamic stabilization, and fusion instrumentation.
Our spine-wear simulation and evaluation capabilities include:
Spine-Wear Simulator Equipment
- Six-station MTS wear simulator with load-soak control station
- Six-degrees-of-freedom load/motion application:
- Flexion/Extension ±10º
- Lateral Bending ±10º
- Rotation ±7.5º
- Axial Load 4kN
- AP Translation ±4.5 mm
- ML Translation ±4.5 mm
- Customized fixtures for mounting implants
- Temperature-controlled and monitored stations that can be maintained at 37 ±2°C
- Distinct testing profiles for lumbar and cervical implants
- Programmable input loading and motion profiles
- Fully validated by comparison with retrieved total disc replacements
Imaging Capabilities 
- Stereo microscopes
- Low-magnification surface imaging (e.g., 1-5×)
- Optical microscopes
- Medium-magnification surface imaging (e.g., 160×)
- Scanning electron microscopes
- High-magnification surface imaging (e.g., 5,000×)
- White-light interferometry
- Average surface roughness evaluation (manufactured vs. worn)
Additional Services
- Gravimetric analysis (0.0001g)
- Serum analysis for particles
- Implant surface characterization before and after wear simulation
- Comparison to retrieval collections