Cementless Hip Stem Anteversion in the Dysplastic Hip: A Comparison of Tapered Wedge Versus Metaphyseal Filling

Abstract Background Appropriate stem anteversion is important for achieving stability of the prosthetic joint in total hip arthroplasty (THA). Anteversion of a cementless femoral stem is affected by the femoral canal morphology and varies according to stem geometry. We investigated the difference an...

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Bibliographic Details
Published in:The Journal of arthroplasty 2016
Main Authors: Taniguchi, Naofumi, MD, PhD, Jinno, Tetsuya, MD, PhD, Koga, Daisuke, MD, PhD, Hagino, Tetsuo, MD, PhD, Okawa, Atsushi, MD, PhD, Haro, Hirotaka, MD, PhD
Format: Article
Language:English
Subjects:
Orthopedics
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Summary:Abstract Background Appropriate stem anteversion is important for achieving stability of the prosthetic joint in total hip arthroplasty (THA). Anteversion of a cementless femoral stem is affected by the femoral canal morphology and varies according to stem geometry. We investigated the difference and variation of the increase in anteversion between two types of cementless stems, and the correlation between each stem and the pre-operative femoral anteversion. Methods We retrospectively compared two groups of hips that underwent THA using a metaphyseal filling stem (78 hips) or a tapered wedge stem (83 hips). All the patients had osteoarthritis due to hip dysplasia. Computed tomography was utilized to measure pre-operative femoral anteversion at five levels, and post-operative stem anteversion. Results The increase in anteversion of the tapered wedge stem group (22.7 ± 11.6°) was more than that of the metaphyseal filling stem group (17.2 ± 8.3°) (p = 0.0007). The variation of the increase in the tapered wedge stem group was significantly larger than that in the metaphyseal filling stem group (p = 0.0016). The metaphyseal filling stem group was more highly and positively correlated with femoral anteversion than the tapered wedge stem group. Conclusion Femoral anteversion affects stem anteversion differently according to stem geometry. The tapered wedge stems had greater variation of the increase in anteversion than did the metaphyseal filling stems. Based on the results of this study, it is difficult to pre-operatively estimate the increase in stem anteversion for tapered wedge stems. Level of evidence LevelⅢ, diagnostic study
ISSN:0883-5403
DOI:10.1016/j.arth.2016.12.020