Table 3.
Comparison of current results with previous studies
| Study | Type of polyethylene liner | Ball diameter (mm) | Urethane/metal shell backing | Liner thickness (mm) | Primary result | Type of study |
|---|---|---|---|---|---|---|
| Livermore et al. [29] (1990) | “Conventional” (details not provided) | 22, 28, 32 | Not applicable (cemented) | Unknown | Greatest mean rate of volumetric wear seen with 32-mm cups | Clinical study, minimum 9.5-year followup |
| Kabo et al. [24] (1993) | “Conventional” (details not provided) | 22, 26, 28, 32 | Unknown | 8 | Volumetric wear rate increased in a linear manner with component diameter | Clinical study |
| Clarke et al. [6] (1996) | Noncrosslinked | 22, 26, 28 | Unknown | 10 | Wear increased with ball diameter | Simulator test |
| Clarke et al. [5] (1997) | Noncrosslinked | 22, 26, 28 | Unknown | Unknown | Wear increased with ball diameter | Simulator test |
| Devane et al. [9] (1997) | “Conventional” (details not provided) | 28, 32 | Metal shell | 2.36–11.36 | Greater volumetric wear rate found with 32-mm-diameter femoral heads | Clinical study |
| Hirakawa et al. [22] (1997) | Gamma sterilized in air | 26, 28, 32 | Metal shell | Unknown | Higher volumetric wear associated with 32-mm components | Clinical study |
| Elfick et al. [13] (1998) | “Conventional” (details not provided) | 22, 32 | Metal shell | 1.8–11 | High volumetric wear rate for the PCA joint attributed entirely to its larger head size | Clinical study |
| McKellop et al. [32] (1999) | Noncrosslinked; crosslinked-remelted, 5 Mrad | 28 | Urethane | 10 | 85% reduction in wear rate | Simulator test |
| Muratoglu et al. [37] (2001) | Gamma sterilized in nitrogen; crosslinked, 9.5 Mrad | 22, 28, 46 | Unknown | 5 (22 mm), 7 (28 mm), 3 (46 mm) | Wear increased with ball diameter for gamma-sterilized polyethylene; wear independent of ball diameter for 9.5-Mrad crosslinked polyethylene | Simulator test |
| Hermida et al. [21] (2003) | Crosslinked, 10.5 Mrad | 28, 32 | Metal shell |
9.4 (28 mm) 7.4 (32 mm) |
Small increase in the mean wear rate with 32-mm liners | Simulator test |
| Shaju et al. [44] (2005) | Sterilized with gamma radiation | 22, 32 | Not applicable (cemented) | 10.8 (22 mm) | Volumetric wear rate higher with 32-mm femoral heads | Clinical study, 11-year followup |
| Geller et al. [17] (2006) | Crosslinked, 10 Mrad | 36, 40 | Metal shell | Unknown | No difference in the median total penetration rates between the two groups | Clinical study, minimum 3-year followup |
| Bragdon et al. [4] (2007) | Crosslinked, 10 Mrad | 28, 36 | Metal shell | Unknown | No difference in total average femoral head penetration between the two groups | Clinical study, 3-year followup |
| Leung et al. [28] (2007) | Noncrosslinked; crosslinked-remelted, 5 Mrad | 28 | Metal shell | Unknown | 94% reduction in wear rate | Clinical study, minimum 5-year followup |
| Kelly et al. [25] (2010) | Gamma sterilized in nitrogen; crosslinked-annealed, 9 Mrad | 36, 44 | Metal shell |
3.8 (44 mm) 7.9 (36 mm) |
3.8-mm liners of highly crosslinked polyethylene did not wear at a higher rate than the 7.9-mm liners of the same material | Simulator test |
| Shen et al. [current study] | Noncrosslinked; crosslinked-remelted, 5 Mrad | 28, 36 | 3 million cycles with urethane; 2.5 million cycles with metal shell | 6 | Crosslinking produced 80% reduction in wear rate for 28 mm, in urethane backing; 76% reduction in wear rate for 28 mm in metal shells; larger diameter increased the wear of noncrosslinked polyethylene but had no systematic effect with 5-Mrad crosslinked polyethylene | Simulator test |