A method of calculation for contact pressure between a femoral head and cup of artificial hip joint

Imado, Keiji; Kido, Yikihito; Nagatoshi, Masuji; Miura, Atsuyoshi; Miyagawa, Hioomi

doi:10.1299/jsmezairiki.2003.0_651

Cited by 3 publications

(3 citation statements)

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“…Mathematical models have also been proposed to calculate the contact stress distribution in normal and dysplastic human joints assuming a zero clearance (Ipavec et al, 1999;Pompe et al, 2003). Imado et al (2005) have estimated the contact stress distribution in an artificial hip joint, but in their model the cup is oriented in the horizontal plane and the external force is applied under non-physiological conditions.…”

Section: Introductionmentioning

confidence: 99%

Design parameters dependences on contact stress distribution in gait and jogging phases after total hip arthroplasty

Rixrath¹,

Wendling-Mansuy²,

Flécher

et al. 2008

Journal of Biomechanics

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Section: Introductionmentioning

confidence: 99%

Design parameters dependences on contact stress distribution in gait and jogging phases after total hip arthroplasty

Rixrath¹,

Wendling-Mansuy²,

Flécher

et al. 2008

Journal of Biomechanics

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“…The load‐based target zone presented by Habor et al 2 depends on the HJF, the head diameter, inner and outer diameter of the liner, and Young's modulus and Poisson's ratio of the liner. A contact area between liner and head is calculated using a method introduced by Imado et al 27 Edge loading was defined by a contact of the outer boundary of the contact patch with the inner rim of the liner 2 . No edge loading is present during the peak force phase of level walking for all cup orientations inside the load‐based target zone.…”

Section: Methodsmentioning

confidence: 99%

Implications of the uncertainty of postoperative functional parameters for the preoperative planning of total hip arthroplasty

Fischer

Tokunaga

Okamoto

et al. 2022

Journal Orthopaedic Research

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The functional parameters pelvic tilt (PT) and hip joint force (HJF) are required to calculate patient‐specific target zones based on the range of motion (ROM) and implant loading for preoperative planning of total hip arthroplasty (THA). Both functional parameters may change after THA. The preoperative prediction of the postoperative PT and HJF is associated with a specific amount of uncertainty. The prediction uncertainty has to be considered in the preoperative planning process to avoid a suboptimal implantation. So far, very little attention has been paid to the necessary reduction of patient‐specific target zones by the prediction uncertainties of postoperative functional parameters. Prediction models for the postoperative PT in standing position and for the HJF during one‐leg stance as a surrogate for the peak force phase during level walking were used to quantify the reduction of the ROM‐ and load‐based target zones of 196 Japanese THA patients. The prediction uncertainty was about 14° for the postoperative standing PT and ranged from 17% body weight to 37% body weight for the components of the HJF. On average, the prosthetic ROM‐based target zone had to be significantly reduced by 43% and the load‐based target zone by 39%. This led to a median reduction of the combined prosthetic ROM‐ and load‐based target zone of 96%. The study sharpens the awareness for the substantial reduction of ROM‐ and load‐based target zones by prediction uncertainties of the postoperative PT and HJF and highlights the importance of further research to improve prediction models for both functional parameters.

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“…The model was adapted to the pelvic width, pelvic height and the position of the greater trochanter. The contact patch is calculated using the Imado model [Imado et al 2005]. The load-based target zone includes all cup orientations without unsuitable edge loading that would occur when the contact patch overlaps with the rim of the cup.…”

Section: Introductionmentioning

confidence: 99%

Patient-specific ROM and load-based Target Zone for Total Hip Arthroplasty and its Application in a retrospective Analysis

Habor¹,

Fischer²,

Tokunaga³

et al.

EPiC Series in Health Sciences

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The outcome of total hip arthroplasty (THA) depends on multiple alignment and design parameters. Unsuitable parameter settings could lead to impingement, dislocation, increased wear, and loosening. This work introduces a method for calculating a patient-specific target zone based on range of motion (ROM) related and load related criteria. Possible bone or prosthesis impingement are analyzed. The resulting hip force is calculated and compared to the pre-operative situation. The edge loading risk is analyzed. Pelvic tilt is considered for the calculation of the ROM and the load. THA parameters fulfilling all criteria are included in the target zone.The above described method has been applied to 30 cases retrospectively. All cases had been planned and navigated on the basis of CT data. From each patient, pre- and post-operative CT and EOS data and Harris Scores were acquired. The pre-operative data served as the input data for the target zone calculator. We hypothesized that cases with post-operative THA parameters inside the target zones have higher scores than other cases.The patients whose implants are within the target zones had higher scores than the remaining patients. Especially patients inside both target zones (combined target zone) had higher scores. The results also show that for 19 out of 30 patients, conventional CT-based planning and navigation does not provide optimal placement regarding the combined target zone. A further validation of the method with a larger sample size is part of our ongoing work.

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A method of calculation for contact pressure between a femoral head and cup of artificial hip joint

Cited by 3 publications

References 0 publications

Design parameters dependences on contact stress distribution in gait and jogging phases after total hip arthroplasty

Design parameters dependences on contact stress distribution in gait and jogging phases after total hip arthroplasty

Implications of the uncertainty of postoperative functional parameters for the preoperative planning of total hip arthroplasty

Patient-specific ROM and load-based Target Zone for Total Hip Arthroplasty and its Application in a retrospective Analysis

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