The influence of head and neck geometry on stability of total hip replacementA mechanical test study

Bader, Rainer; Scholz, R.; Steinhauser, E.; Zimmermann, Susanne; Busch, Raymonde; Mittelmeier, Wolfram

doi:10.1080/00016470410001178-1

Cited by 51 publications

(7 citation statements)

References 16 publications

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“…Additionally, impingement limits the ROM and is a common cause of postoperative instability [47,65]. ROM analyses have raised much attention from the research community using experimental [24][25][26][27][28][29] and numerical methods [21,30,43,44,[46][47][48][49][50]. However, to the best of our knowledge, there is no approach published to assess ROM after THR in surgery planning without applying additional radiation to the patient; for example, by CT scanning.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, the occurrence of impingement is manually assessed by an orthopedic surgeon, by intraoperatively imposing specific motion patterns while the impingement is detected [23]. To analyze the maximum ROM of different implant designs, several experimental [24][25][26][27][28][29] and computational studies [13,18,20,21,23,[30][31][32][33][34][35][36][37][38], using computer-aided design (CAD), finite element analyses, or multibody simulations, have been conducted. Previous studies described the effect of the orientation of the acetabular cup, prosthetic head size on the impingement, and risk of dislocation [21,39,40].…”

Section: Introductionmentioning

confidence: 99%

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An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

et al. 2021

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The calculation of range of motion (ROM) is a key factor during preoperative planning of total hip replacements (THR), to reduce the risk of impingement and dislocation of the artificial hip joint. To support the preoperative assessment of THR, a magnetic resonance imaging (MRI)-based computational framework was generated; this enabled the estimation of patient-specific ROM and type of impingement (bone-to-bone, implant-to-bone, and implant-to-implant) postoperatively, using a three-dimensional computer-aided design (CAD) to visualize typical clinical joint movements. Hence, patient-specific CAD models from 19 patients were generated from MRI scans and a conventional total hip system (Bicontact® hip stem and Plasmacup® SC acetabular cup with a ceramic-on-ceramic bearing) was implanted virtually. As a verification of the framework, the ROM was compared between preoperatively planned and the postoperatively reconstructed situations; this was derived based on postoperative radiographs (n = 6 patients) during different clinically relevant movements. The data analysis revealed there was no significant difference between preoperatively planned and postoperatively reconstructed ROM (∆ROM) of maximum flexion (∆ROM = 0°, p = 0.854) and internal rotation (∆ROM = 1.8°, p = 0.917). Contrarily, minor differences were observed for the ROM during maximum external rotation (∆ROM = 9°, p = 0.046). Impingement, of all three types, was in good agreement with the preoperatively planned and postoperatively reconstructed scenarios during all movements. The calculated ROM reached physiological levels during flexion and internal rotation movement; however, it exceeded physiological levels during external rotation. Patients, where implant-to-implant impingement was detected, reached higher ROMs than patients with bone-to-bone impingement. The proposed framework provides the capability to predict postoperative ROM of THRs.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

et al. 2021

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“…Thus there was no control group with alternative head sizes for the same cup size. But for geometrical reasons larger heads should permit a bigger ROM (22). For migration measurements we accept that the method used (15) has a low accuracy but as all our revised cups had obvious changes in inclination we believed that we would not have missed patients with radiological loosening and pending failure.…”

Section: Discussionmentioning

confidence: 99%

Poor Outcome of a Spherical Pressfit cup with a Modern Ceramic Liner: A Prospective Cohort Study of 181 Cups

et al. 2014

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A spherical pressfit cup with a new ceramic liner was introduced in a clinical trial in order to improve range of motion and reduce wear induced problems. The early clinical and radiological outcome was assessed.In a prospective cohort study 181 hips received a seleXys TH+ cup (Mathys, Bettlach, Switzerland) in combination with a third generation ceramic liner (ceramys, Mathys, Bettlach, Switzerland). The Harris Hip Score (HHS), pain (VAS) and range of motion (ROM) were recorded, cup migration and inclination were measured. Experience of any noise was documented.Fourteen hips were radiologically loose, seven of them were revised. Two-year survival of the cup was 92% with radiological loosening as the endpoint. There was no correlation between head size and ROM, no patient had a dislocation. There were no ceramic fractures. Two patients experienced squeaking and three clicking at final follow-up.Reasons for loosening might have been multifactorial but the rate of failure was unacceptably high. The use of large heads did not improve the ROM and development of noise could not be prevented with the modern ceramic. We abandoned the use of this implant system.

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“…Elevated rim/skirt designs for liners will affect the results of any computer model, as shown in previous studies. [14][15][16][17][18] To lower the dislocation rate, patients need to have an impingement-free ROM for different daily activities. Investigators have published their results of computer simulation and mathematical formulae for hip prosthetic ROM with optimal acetabular angles and a cylindrical femoral neck design.…”

Section: Discussionmentioning

confidence: 99%

Femoral stem neck geometry determines hip range of motion shape

Pour

Lazennec

Patel

et al. 2021

Bone & Joint Research

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Aims In computer simulations, the shape of the range of motion (ROM) of a stem with a cylindrical neck design will be a perfect cone. However, many modern stems have rectangular/oval-shaped necks. We hypothesized that the rectangular/oval stem neck will affect the shape of the ROM and the prosthetic impingement. Methods Total hip arthroplasty (THA) motion while standing and sitting was simulated using a MATLAB model (one stem with a cylindrical neck and one stem with a rectangular neck). The primary predictor was the geometry of the neck (cylindrical vs rectangular) and the main outcome was the shape of ROM based on the prosthetic impingement between the neck and the liner. The secondary outcome was the difference in the ROM provided by each neck geometry and the effect of the pelvic tilt on this ROM. Multiple regression was used to analyze the data. Results The stem with a rectangular neck has increased internal and external rotation with a quatrefoil cross-section compared to a cone in a cylindrical neck. Modification of the cup orientation and pelvic tilt affected the direction of projection of the cone or quatrefoil shape. The mean increase in internal rotation with a rectangular neck was 3.4° (0° to 7.9°; p < 0.001); for external rotation, it was 2.8° (0.5° to 7.8°; p < 0.001). Conclusion Our study shows the importance of attention to femoral implant design for the assessment of prosthetic impingement. Any universal mathematical model or computer simulation that ignores each stem’s unique neck geometry will provide inaccurate predictions of prosthetic impingement. Cite this article: Bone Joint Res 2021;10(12):780–789.

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The influence of head and neck geometry on stability of total hip replacementA mechanical test study

Cited by 51 publications

References 16 publications

An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

Poor Outcome of a Spherical Pressfit cup with a Modern Ceramic Liner: A Prospective Cohort Study of 181 Cups

Femoral stem neck geometry determines hip range of motion shape

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