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Primary stability of two uncementedacetabular components of different geometry: hemispherical or peripherallyenhanced?
Bottom Line:
The objective was to determine whether altered geometry resulted in better primary stability.However, the PSL component required a significantly higher seating force than the hemispherical cup in the high-density bone analogue (p = 0.006).Our results, if translated clinically, suggest that a purely hemispherical geometry may have an advantage over a peripherally enhanced geometry in high density bone stock.
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PubMed Central - PubMed
Affiliation: Golden Jubilee National Hospital, Departmentof Orthopaedics, Agamemnon Street, Clydebank, WestDunbartonshire G81 4DY, UK.
ABSTRACT
Objective: This study compared the primary stability of two commercially available acetabular components from the same manufacturer, which differ only in geometry; a hemispherical and a peripherally enhanced design (peripheral self-locking (PSL)). The objective was to determine whether altered geometry resulted in better primary stability. Methods: Acetabular components were seated with 0.8 mm to 2 mm interference fits in reamed polyethylene bone substrate of two different densities (0.22 g/cm(3) and 0.45 g/cm(3)). The primary stability of each component design was investigated by measuring the peak failure load during uniaxial pull-out and tangential lever-out tests. Results: There was no statistically significant difference in seating force (p = 0.104) or primary stability (pull-out p = 0.171, lever-out p = 0.087) of the two components in the low-density substrate. Similarly, in the high-density substrate, there was no statistically significant difference in the peak pull-out force (p = 0.154) or lever-out moment (p = 0.574) between the designs. However, the PSL component required a significantly higher seating force than the hemispherical cup in the high-density bone analogue (p = 0.006). Conclusions: Higher seating forces associated with the PSL design may result in inadequate seating and increased risk of component malpositioning or acetabular fracture in the intra-operative setting in high-density bone stock. Our results, if translated clinically, suggest that a purely hemispherical geometry may have an advantage over a peripherally enhanced geometry in high density bone stock. Cite this article: Bone Joint Res 2013;2:264-9. No MeSH data available. Related in: MedlinePlus |
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f3: Seating force for hemispherical andperipheral self-locking (PSL) implant designs in low- (0.22 g/cm3)and high-density (0.45 g/cm3) substrate. The error barsdenote the range of values (* p = 0.006). |
View Article: PubMed Central - PubMed
Affiliation: Golden Jubilee National Hospital, Departmentof Orthopaedics, Agamemnon Street, Clydebank, WestDunbartonshire G81 4DY, UK.
Objective: This study compared the primary stability of two commercially available acetabular components from the same manufacturer, which differ only in geometry; a hemispherical and a peripherally enhanced design (peripheral self-locking (PSL)). The objective was to determine whether altered geometry resulted in better primary stability.
Methods: Acetabular components were seated with 0.8 mm to 2 mm interference fits in reamed polyethylene bone substrate of two different densities (0.22 g/cm(3) and 0.45 g/cm(3)). The primary stability of each component design was investigated by measuring the peak failure load during uniaxial pull-out and tangential lever-out tests.
Results: There was no statistically significant difference in seating force (p = 0.104) or primary stability (pull-out p = 0.171, lever-out p = 0.087) of the two components in the low-density substrate. Similarly, in the high-density substrate, there was no statistically significant difference in the peak pull-out force (p = 0.154) or lever-out moment (p = 0.574) between the designs. However, the PSL component required a significantly higher seating force than the hemispherical cup in the high-density bone analogue (p = 0.006).
Conclusions: Higher seating forces associated with the PSL design may result in inadequate seating and increased risk of component malpositioning or acetabular fracture in the intra-operative setting in high-density bone stock. Our results, if translated clinically, suggest that a purely hemispherical geometry may have an advantage over a peripherally enhanced geometry in high density bone stock. Cite this article: Bone Joint Res 2013;2:264-9.
No MeSH data available.
