Effects of screw eccentricity on the initial stability of the acetabular cup
Open Access
- 1 September 2006
- journal article
- research article
- Published by Springer Science and Business Media LLC in International Orthopaedics
- Vol. 31 (4), 451-455
- https://doi.org/10.1007/s00264-006-0226-4
Abstract
One of the major failure modes of cementless acetabular components is the loosening of the acetabular cup, which is mostly attributable to insufficient initial stability. A hemispherical cup with a porous coating which is inserted with press-fit fixation and secured with several screws is one of the most widely used approaches. Many studies have found that bone screws are very helpful aids for cup fixation, but the optimal surgical technique for inserting screws has not been clearly reported. In this study, hemispherical cups were fixed into blocks of foam bone with zero to three screws. The effects of three types of screw eccentricity (a 1-mm offset and angular eccentricities of 15° and 25°) on the initial stability of the acetabular cup were evaluated. The experimental results indicate that increasing the number of screws enhances the cup stability in the case of ideal screwing (i.e., with no eccentricity). An angular eccentricity of 15° did not affect the cup stability for fixation with one or two screws. However, the presence of 25° of angular eccentricity significantly reduced the stability of the cup, while 1 mm of offset eccentricity produced an even greater impact.Keywords
This publication has 26 references indexed in Scilit:
- Failure of hydroxyapatite-coated acetabular cupsThe Journal of Bone and Joint Surgery, 2002
- The effect of interfacial parameters on cup–bone relative micromotions: A finite element investigationJournal of Biomechanics, 2001
- Clinical and radiographic evaluation of the Harris-Galante Cup: Incidence of wear and osteolysis at 7 to 9 years follow-upThe Journal of Arthroplasty, 2000
- A quantitative in vitro assessment of fit and screw fixation on the stability of a cementless hemispherical acetabular componentThe Journal of Arthroplasty, 1994
- Failed innovation in total hip replacement: Diagnosis and proposals for a cureActa Orthopaedica, 1993
- Acetabular micromotion as a measure of initial implant stability in primary hip arthroplasty: An in vitro comparison of different methods of intial acetabular component fixationThe Journal of Arthroplasty, 1992
- Migration of porous coated acetabular prostheses fixed with screws: Roentgen stereophotogrammetric analysisJournal of Orthopaedic Research, 1992
- Screw-augmented fixation of acetabular components: A mechanical model to determine optimal screw placementThe Journal of Arthroplasty, 1991
- In vitro initial fixation of porous-coated acetabular total hip components: A biomechanical comparative studyThe Journal of Arthroplasty, 1989
- Observations on the Effect of Movement on Bone Ingrowth into Porous-Surfaced ImplantsPublished by Ovid Technologies (Wolters Kluwer Health) ,1986