Table 6.
Comparison of fixed bearing knee wear assessments from other studies and our study
| Study | Bearing type | Implant | Number | In vivo duration (months)* | Assessment method | Wear rate | Notes/Findings |
|---|---|---|---|---|---|---|---|
| Benjamin et al. [3] | Fixed | AMK® + PFC® | 24 | 68 (9–132) | Through-thickness measurement Laser scan for volume Visual rating of damage pattern (1–6) |
0.35 mm/year 794 mm3/year (wear volume) |
Wear rates decreased with duration |
| Synatomic | 9 | ||||||
| Fixed | Synatomic | 9 | |||||
| Li et al. [26] | Fixed | AMK®, PFC® Genesis, IB-II |
55 | 1–73 | Visual rating of damage modes (0–3) Removal of stamped markings Extrusions into screw holes |
87 mg/year | Wear rate estimated for one insert only |
| Surace et al. [36] | Fixed | MG® | 11 | 64 (4–156) | Visual rating of damage modes (0–3) Extruded pegs with optical zoom |
Peg heights 0 to 0.317 mm Pegs indicate most wear posterior, medial |
|
| Fixed | MG II® | 14 | |||||
| Conditt et al. [12] | Fixed | AMK® | 15 | 91 (36–146) | Linear laser scans of backside, 3D computer reconstruction for volume | 138 mm3/year (wear volume) | Significantly more wear medially |
| Crowninshield et al. [13] | Fixed | NexGen® | 43 | 33 (2–80) | Visual rating of damage modes (0–3) Profilometry of engraved lettering |
0.0041 mm/year | Damage modes: no correlation with duration Backside wear has partial association with duration |
| Engh et al. [18] | Fixed | AMK® | 31 | 32 (1–141) | Through-thickness measurement (n = 6) Visual rating of damage modes (0–3) |
0.047 mm/year | Surface damage did not reflect material lost |
| Current study | Fixed | Sigma® | 218 | 65 (2.1–179) | Through-thickness and backside measurements Backside wear volume calculated |
0.07 mm/year (total) 0.02 mm/year (backside) 44 mm3/year (wear volume) |
Medial wear bias; wear rate increases with duration No wear difference between CR and PS inserts |
* Values are expressed as mean, with range in parentheses; CR = cruciate retaining; PS = posterior stabilized.