Dataset Information

Dual-taper modular hip implant: Investigation of 3-dimensional surface scans for component contact, shape, and fit.

ABSTRACT:

Background

The etiology of wear particle generation and subsequent corrosion in modular total hip arthroplasty implants likely begins with mechanical fretting. The purpose of this study was to determine geometric features of the male and female taper surfaces that drive stability within the neck-stem junction.

Methods

Eighteen modular hip components received 3-dimensional surface scans to examine the neck-stem taper junction using an optical scanner. The normal distance between the surfaces of the neck taper as seated in the stem slot was measured and produced a color map of the contact proximity. Contour plots identified surface shape variation and contact. Angle measurements and neck seated depth were analyzed by regression.

Results

The typical features observed were (1) a vertical line of contact at one end of the transition from the flat surface to the radius surface; (2) a vertical line of contact in the radius surface just past the centerline; (3) a concavity along the flat surface between the neck and stem components; and (4) one of the neck flat surfaces was closer to its mating surface on the stem. The seated depth of the neck was dependent on the taper angles in the flat section of the neck (R² = 0.5000, P = .0332).

Conclusions

The shape of the neck and stem tapers deviate from ideal design dimensions, contributing to relative motions between the neck and stem. While these processes are not proven to directly cause implant failure, they may place the implants at higher risk for failure.

SUBMITTER: Frisch NB

PROVIDER: S-EPMC6123237 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Publications

Dual-taper modular hip implant: Investigation of 3-dimensional surface scans for component contact, shape, and fit.

Frisch Nicholas B NB Lynch Jonathan R JR Pourzal Robin R Banglmaier Richard F RF Silverton Craig D CD

Arthroplasty today 20180721 3

<h4>Background</h4>The etiology of wear particle generation and subsequent corrosion in modular total hip arthroplasty implants likely begins with mechanical fretting. The purpose of this study was to determine geometric features of the male and female taper surfaces that drive stability within the neck-stem junction.<h4>Methods</h4>Eighteen modular hip components received 3-dimensional surface scans to examine the neck-stem taper junction using an optical scanner. The normal distance between th ...[more]

PMID: 30186924

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Project description:BackgroundAnatomical variation may represent a challenge in achieving a close fit between a prosthesis and a patient's osseous geometry in total knee arthroplasty (TKA). The purposes of this study were to determine whether the shape of the distal part of the femur differs among ethnicities, whether these differences affect the fit of the femoral component of a standard prosthesis, and whether the additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior dimension improves femoral component fit across ethnicities.MethodsFemoral dimensions were measured intraoperatively during 967 TKAs performed using the same type of prosthesis in patients of 5 different ethnicities. Aspect ratios were calculated to determine whether the shapes of the femora differed among ethnicities. The component fit ("perfect," overhang, or underhang) when only standard prostheses were available was compared with the fit when both standard and narrow prostheses were available in all ethnic groups. This enabled us to determine whether the femoral component fit was improved by the additional availability of the narrow version.ResultsWide variations in shape were found among ethnicities as were variations among individuals of the same ethnicity. Differences in shape among ethnicities influenced the rate of overhang. However, overhang was more frequent at the trochlear than at the condylar level across all ethnicities. The availability of both the standard and the narrow femoral components improved the rate of a perfect fit in women in 3 of the 5 ethnic groups and reduced the overhang rate in women in all 5 of the ethnic groups. In contrast, only modest improvements in femoral component fit, which were not statistically significant, were seen in men.ConclusionsThe shape of the distal part of the femur varies not only among ethnicities but also within ethnic groups, leading to a high prevalence of overhang when only standard prostheses are available. The additional availability of a femoral component with a reduced mediolateral dimension for the same anteroposterior size can reduce overhang and improve component fit across ethnicities.

Dataset Information

Dual-taper modular hip implant: Investigation of 3-dimensional surface scans for component contact, shape, and fit.

Background

Methods

Results

Conclusions

Publications

Dual-taper modular hip implant: Investigation of 3-dimensional surface scans for component contact, shape, and fit.

Similar Datasets

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