Comparison of implant characteristics among different materials utilized in interbody cages.
| Implant Material | Effective Modulus (GPa)7–11 | Porosity | Surface Chemistry | Topography | Shear Resistance |
| Cortical bone | 18 | + | + | + | Yes |
| PEEK | 4 | − | − | − | Yes |
| Ti | 110 | +/− | + | +/− | Yes |
| Ti-coated PEEK | 110 | +/− | + | + | No |
| Three-dimensional-printed Ti | 0.9–2.5 | + | + | + | Yes |
Characteristics of each implant are designated by −, +/−, or +. Minimal to no effect of a characteristic is designated by “−”, while “+/−” indicates the characteristic varies dependent on the construct, and “+” designates those implants that possess the characteristic.
PEEK, polyetheretherketone; Ti, titanium.