Implant position calculation for acetabular cup placement considering pelvic lateral tilt and inclination

Chen, Eduard; Goertz, Wolfgang; Lill, Christophe

doi:10.1080/10929080601090516

Cited by 14 publications

(22 citation statements)

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“…However, the relative cup abduction angle varies with the pelvic orientation, as it increases with a posterior pelvic extension. 11 When moving from a standing position to a sitting position, the pelvis extends posteriorly inducing an average increase in cup abduction angle of about 208. 11 Thus, high cup abduction angles (above 708) may be reached in some functional positions even if in the standing position its value is within the recommended range.…”

Section: Discussionmentioning

confidence: 99%

In vitro investigation of friction under edge‐loading conditions for ceramic‐on‐ceramic total hip prosthesis

Sariali

Stewart

Jin

et al. 2010

Journal Orthopaedic Research

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Edge-loading generates higher wear rates in ceramic-on-ceramic total hip prosthesis (THP). To investigate the friction coefficient (FC) in these conditions, three alumina ceramic (Biolox Forte) 32 mm-diameter components were tested using a hip friction simulator. The cup was positioned with a 758 abduction angle to achieve edge-loading conditions. The motion was first applied along the edge and then across the edge of the cup. First, tests were conducted under lubricated conditions with 25% bovine serum. Next, to simulate an extremely high contact pressure, the tests were run with the addition of a third body alumina ceramic chip inserted between the edge of the cup and the head. Engineering blue was used to analyze the contact area. Reference values were determined using a 08 cup abduction angle. Edge loading was achieved. The FC increased by three-to sixfold when the motion was applied along the edge, and by 70% when the motion was applied across the edge. However, the FC value was still low (about 0.1), which is similar to metal-on-metal THP. With the third body alumina ceramic particle inserted, the FC was 26 times higher than in the ideal conditions and intermittent squeaking occurred. High cup abduction angles may generate edge-loading and an increase in the friction coefficient for ceramic THP. Keywords: friction coefficient; ceramic; hip prosthesis; edge loading; squeaking Ceramic-on-ceramic retrievals from total hip prostheses (THP) show higher wear rates than those predicted on simulators under normal conditions. 1 This discrepancy is related to edge loading that can occur clinically due to lateralization (microseparation) of the femoral head relative to the acetabular cup, causing a localized increase in stress and wear. Although a number of experimental wear simulator studies have been conducted that reproduce edge loading under microseparation conditions, the general tribological mechanism under this adverse condition is unclear. Friction levels, for example, have not been reported under these edgeloading conditions. We hypothesized that the friction coefficient (FC) increases under edge-loading conditions. A study to test such an hypothesis is important as it may assist in the understanding of clinical hip noises such as squeaking. 2,3 In addition, FC values are needed to develop computational models of contact mechanics and wear prediction under edge loading conditions, which can help improve implant design. Our goals were to determine the FC under edge loading for alumina ceramic-on-ceramic THP and to investigate the effect of the addition of alumina debris on the FC and the generation of squeaking. MATERIALS AND METHODS SpecimensThree Biolox Forte heads and liners were tested on the Leeds PROSIM 1 friction simulator. The components had a diameter of 32 mm, with a radial clearance of 30 mm. All specimens were manufactured by Ceramtec (Plochingen, Germany). Before testing, specimens were cleaned with a washing-up liquid, rinsed in water, and then ultrasonically cleaned in an isopropanol ...

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Section: Discussionmentioning

confidence: 99%

In vitro investigation of friction under edge‐loading conditions for ceramic‐on‐ceramic total hip prosthesis

Sariali

Stewart

Jin

et al. 2010

Journal Orthopaedic Research

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“…2 Relationship of the forward and backward variability of the angle of the sagittal anterior pelvic plane angle (SAPPA) (black columns for the normal subjects, white columns for the low back pain cases) SS and the sagittal acetabular tilt [9]. Chen, by a mathematical model and on a "Sawbone", reported a variation of the cup position from 15°anteversion in 0°p elvic inclination to 0.5°retroversion in 15°forwards sagittal pelvic tilting [4].The influence of the spine on the sagittal pelvic tilt and on the cup orientation was pointed out by Tang and Chiu for patients with ankylosing spondylitis [20]. They advised adapting the usual positioning of the cup by reducing the inclination and anteversion by 5°for each 10°of sagittal mal-rotation beyond 20°.…”

Section: Discussionmentioning

confidence: 99%

Influence of the sagittal balance of the spine on the anterior pelvic plane and on the acetabular orientation

Legaye

2009

International Orthopaedics (SICOT)

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The Anterior Pelvic Plane (APP), defined by the anterior superior iliac spines and the pubic tubercle, was commonly used as reference for positioning and postoperative evaluation of the orientation of the acetabular cup in total hip arthroplasty. APP was assumed to be vertical, but was not observed always so, mostly because of associated spinal diseases inducing perturbations in the harmony of the sagittal balance of the pelvi-spinal unit. Consequently a sagittal rotation of the pelvis occurs, and so a tilt of the APP which alters directly the orientation of the cup in upright position. An analysis of the APP tilt related to the sagittal balance of the spine was provided and its implication on the cup orientation. It appeared essential for an individual adjustment of the cup positioning to avoid a functional malposition which can lead to an increased risk of dislocation and impingement.Résumé Le plan antérieur pelvien (APP) définit par les crêtes iliaques et le pubis est communément appelé plan de référence pour le positionnement et l'orientation de la cupule acétabulaire dans les prothèses totales de hanche. Ce plan peut être modifié par la position verticale et du fait de pathologies associées au niveau de la colonne vertébrale entraînant une perturbation des courbures et de la balance pelvienne. En conséquence, une rotation sagittale du pelvis peut survenir avec conséquences sur le plan pelvien antérieur APP. Ceci peut avoir des conséquences directes sur l'orientation de la cupule en position debout. Une analyse de ce plan pelvien antérieur APP et des modifications entraînées par la balance pelvienne sont indispensables. Il apparaît essentiel d'ajuster le positionnement de la cupule de façon à éviter une mal position qui peut être responsable d'un risque accru de luxations ou de conflits.

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“…2). The anterior pelvic plane has also been called pelvic inclination and reclination [3,6] and the pelvic flexion angle [35].…”

Section: Anteroposterior Pelvic Tiltmentioning

confidence: 99%

Imaging and Navigation Measurement of Acetabular Component Position in THA

Wan

Malik

Jaramaz

et al. 2009

Clinical Orthopaedics &Amp; Related Research

190

157

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There are six different definitions of acetabular position based on observed inclination and anteversion made in either the (1) anterior pelvic plane or (2) coronal planes and based on whether each of the observations made in one of these two planes is (1) anatomic, (2) operative, or (3) radiographic. Anteroposterior pelvic tilt is the angle between the anterior pelvic plane and the coronal plane of the body. The coronal plane is a functional plane and the anterior pelvic plane is an anatomic pelvic plane. A cup may be in the "safe zone" by one definition but may be out of the "safe zone" by another definition. We reviewed published studies, analyzed the difference in varying definitions, evaluated the influence of the anterior pelvic tilt, and provided methods to convert from one definition to another. We recommend all inclination and anteversion measurements be converted to the radiographic inclination and anteversion based on the coronal plane, which is equivalent to the inclination and anteversion on the anteroposterior pelvic radiograph.

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Implant position calculation for acetabular cup placement considering pelvic lateral tilt and inclination

Cited by 14 publications

References 0 publications

In vitro investigation of friction under edge‐loading conditions for ceramic‐on‐ceramic total hip prosthesis

In vitro investigation of friction under edge‐loading conditions for ceramic‐on‐ceramic total hip prosthesis

Influence of the sagittal balance of the spine on the anterior pelvic plane and on the acetabular orientation

Imaging and Navigation Measurement of Acetabular Component Position in THA

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