The Experts below are selected from a list of 4719 Experts worldwide ranked by ideXlab platform
Henrik Malchau - One of the best experts on this subject based on the ideXlab platform.
-
a multi centre evaluation of Acetabular Cup positining in robotic assisted total hip arthroplasty
2018Co-Authors: J Dounchis, Leah Elson, Charles R Bragdon, D Padgett, M R Illgen, Henrik MalchauAbstract:IntroductionIn total hip arthroplasty, the positioning of the Acetabular Cup, in particular, has been shown to play an important role in the survivorship of the prosthetic joint. The commonly accepted “safe zone” extends from 5–30° of anteversion to 30–50° of inclination. However, several studies have utilized a more restrictive safe zone of 5–25° of anteversion and 30–45° of inclination, a modification of the Lewinnek zone. Many attempts have been made to develop a more reliable method of positioning the Acetabular component. Robotic-assisted surgery is one such method. The purpose of this study was to compare the resulting position of the Acetabular component after robotic-assisted surgery with the intraoperative robotic data to determine if improved accuracy can be achieved with the robotic-assisted method.MethodsOne hundred and nineteen patients received THA, at four different medical centers in the United States, using a haptic robotic arm. Pre-operative CT scans were obtained for all patients and us...
-
Acetabular Cup position and risk of dislocation in primary total hip arthroplasty
2017Co-Authors: Kurt G Seagrave, Henrik Malchau, Anders Troelsen, Henrik Husted, Kirill GromovAbstract:Background and purpose - Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including Acetabular Cup positioning. Optimal values for Cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring Cup placement, target zones for Cup positioning, and the association between Cup positioning and dislocation following primary THA. Methods - A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared Acetabular Cup positioning and the risk of dislocation. Surgical approach and methods for measurement of Cup angles were also considered. Results - 28 articles were determined to be relevant to our research question. Some articles demonstrated that Cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of Cup anteversion and inclination. Most of the articles that assessed Cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation - The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for Cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing Cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of Cup positioning should be implemented to allow comparison between studies.
-
precision of radiostereometric analysis rsa of Acetabular Cup stability and polyethylene wear improved by adding tantalum beads to the liner
2015Co-Authors: Audrey K Nebergall, Henrik Malchau, Kevin A Rader, Henrik Palm, Meridith E GreeneAbstract:Background and purpose — In traditional radiostereometric analysis (RSA), 1 segment defines both the Acetabular shell and the polyethylene liner. However, inserting beads into the polyethylene liner permits employment of the shell and liner as 2 separate segments, enabling distinct analysis of the precision of 3 measurement methods in determining femoral head penetration and shell migration.Patients and methods — The UmRSA program was used to analyze the double examinations of 51 hips to determine if there was a difference in using the shell-only segment, the liner-only segment, or the shell + liner segment to measure wear and Acetabular Cup stability. The standard deviation multiplied by the critical value (from a t distribution) established the precision of each method.Results — Due to the imprecision of the automated edge detection, the shell-only method was least desirable. The shell + liner and liner-only methods had a precision of 0.115 mm and 0.086 mm, respectively, when measuring head penetration....
-
a multi centre evaluation of Acetabular Cup positining in robotic assisted total hip arthroplasty
2013Co-Authors: J Dounchis, Leah Elson, Charles R Bragdon, D Padgett, M R Illgen, Henrik MalchauAbstract:Introduction In total hip arthroplasty, the positioning of the Acetabular Cup, in particular, has been shown to play an important role in the survivorship of the prosthetic joint. The commonly accepted “safe zone” extends from 5–30° of anteversion to 30–50° of inclination. However, several studies have utilized a more restrictive safe zone of 5–25° of anteversion and 30–45° of inclination, a modification of the Lewinnek zone. Many attempts have been made to develop a more reliable method of positioning the Acetabular component. Robotic-assisted surgery is one such method. The purpose of this study was to compare the resulting position of the Acetabular component after robotic-assisted surgery with the intraoperative robotic data to determine if improved accuracy can be achieved with the robotic-assisted method. Methods One hundred and nineteen patients received THA, at four different medical centers in the United States, using a haptic robotic arm. Pre-operative CT scans were obtained for all patients and used during the planning of the procedure, at which point the proposed component size and positioning was determined. Preparation of the Acetabular bone bed, as well as impaction of the Acetabular component itself, was performed using the robotic device. Using an AP Pelvis and Cross-Table Lateral radiograph, each patient9s resulting Acetabular inclination and version was measured using the Hip Analysis Suite software. The component position retrieved from the robot was compared to the measured values from the radiographs. The positioning data was compared to two safe zones described above. Results Of the 119 surgeries performed, 110 could be read with the hip analysis suite software. Radiographically, the average inclination was 40.4° ± 4.1° with a range of 27.4°–53.7° and the average anteversion was 21.5° ± 6.1° with a range of 5.2°–42.6°. As measured inter-operatively, 100% of the components fell within the Lewinnek safe zone and 96% fell within the more restrictive safe zone. Radiographically, 88% of the cases fell within the Lewinnek safe zone and 73% fell within the restrictive safe zone. The mean difference between the inclination and version of the component determined by the robot and by radiographic analysis was 0.31° and 2.1° respectively. Conclusions The inclination and version of the Acetabular components implanted with robotic assistance as determined inter-operatively were within the commonly accepted limits in all cases. Variations between the Cup positions determined inter-operatively and from the post-operative radiographs are related to differences in the radiographic project of the hip and the robotic registration of the pelvis from CT images. In no procedure was the radiographic inclination greater than 54° or version less than 5°. In this study, the use of robotic-assisted positioning of the Acetabular component has significantly reduced the variability of component orientation. This improved reliability of positioning should result in an increase of favourable functioning, and a decrease in early complications such as dislocation, impingement, and component wear.
-
Acetabular Cup positioning in revision total hip arthroplasty with paprosky type iii Acetabular defects martell radiographic analysis
2013Co-Authors: Ho Rim Choi, David E Anderson, Scott Foster, Matthew D Beal, Joann Lee, C Barr, Henrik Malchau, Joseph C Mccarthy, Youngmin KwonAbstract:Purpose This study evaluates Acetabular Cup position in the setting of revision total hip arthroplasty (THA) with severe Acetabular bone defects.
Guillaume Haiat - One of the best experts on this subject based on the ideXlab platform.
-
dependence of the primary stability of cementless Acetabular Cup implants on the biomechanical environment
2019Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Elisabeth Tabor, Katharina Immel, Victor Housset, Charleshenri Flouzatlachaniette, Guillaume HaiatAbstract:Biomechanical phenomena occurring at the bone–implant interface during the press-fit insertion of Acetabular Cup implants are still poorly understood. This article presents a nonlinear geometrical ...
-
influence of soft tissue in the assessment of the primary fixation of Acetabular Cup implants using impact analyses
2018Co-Authors: Romain Bosc, Philippe Hernigou, Vuhieu Nguyen, Charleshenri Flouzatlachaniette, Antoine Tijou, Giuseppe Rosi, Jeanpaul Meningaud, Guillaume HaiatAbstract:Background: The Acetabular Cup (AC) implant primary stability is an important determinant for the success of cementless hip surgery but it remains difficult to assess the AC implant fixation in the clinic. A method based on the analysis of the impact produced by an instrumented hammer on the ancillary has been developed by our group (Michel et al., 2016a). However, the soft tissue thickness present around the acetabulum may affect the impact response, which may hamper the robustness of the method. The aim of this study is to evaluate the influence of the soft tissue thickness (STT) on the Acetabular Cup implant primary fixation evaluation using impact analyses. Methods: To do so, different AC implants were inserted in five bovine bone samples. For each sample, different stability conditions were obtained by changing the cavity diameter. For each configuration, the AC implant was impacted 25 times with 10 and 30 mm of soft tissues positioned underneath the sample. The averaged indicator Im was determined based on the amplitude of the signal for each configuration and each STT and the pull-out force was measured. Findings: The results show that the resonance frequency of the system increases when the value of the soft tissue thickness decreases. Moreover, an ANOVA analysis shows that there was no significant effect of the value of soft tissue thickness on the values of the indicator Im (F = 2.33; p-value = 0.13). Interpretation: This study shows that soft tissue thickness does not appear to alter the prediction of the Acetabular Cup implant primary fixation obtained using the impact analysis approach, opening the path towards future clinical trials.
-
influence of anisotropic bone properties on the biomechanical behavior of the Acetabular Cup implant a multiscale finite element study
2017Co-Authors: Vuhieu Nguyen, Adrien Michel, Romain Bosc, Maria Letizia Raffa, Giuseppe Rosi, Jeanpaul Meningaud, Salah Naili, Christine Chappard, Naoki Takano, Guillaume HaiatAbstract:AbstractAlthough the biomechanical behavior of the Acetabular Cup (AC) implant is determinant for the surgical success, it remains difficult to be assessed due to the multiscale and anisotropic nature of bone tissue. The aim of the present study was to investigate the influence of the anisotropic properties of peri-implant trabecular bone tissue on the biomechanical behavior of the AC implant at the macroscopic scale. Thirteen bovine trabecular bone samples were imaged using micro-computed tomography (μCT) with a resolution of 18 μm. The anisotropic biomechanical properties of each sample were determined at the scale of the centimeter based on a dedicated method using asymptotic homogenization. The material properties obtained with this multiscale approach were used as input data in a 3D finite element model to simulate the macroscopic mechanical behavior of the AC implant under different loading conditions. The largest stress and strain magnitudes were found around the equatorial rim and in the polar are...
-
Finite element model of the impaction of a press-fitted Acetabular Cup
2017Co-Authors: Adrien Michel, Philippe Hernigou, Romain Bosc, Vuhieu Nguyen, Romain Vayron, Salah Naili, Guillaume HaiatAbstract:Press-fit surgical procedures aim at providing primary stability to Acetabular Cup (AC) implants. Impact analysis constitutes a powerful approach to retrieve the AC implant insertion properties. The aim of this numerical study was to investigate the dynamic interaction occurring between the hammer, the ancillary and bone tissue during the impact and to assess the potential of impact analysis to retrieve AC implant insertion conditions. A dynamic two-dimensional axisymmetric model was developed to simulate the impaction of the AC implant into bone tissue assuming friction at the bone–implant interface and large deformations. Different values of interference fit (from 0.5 to 2 mm) and impact velocities (from 1 to 2 m.s−1) were considered. For each configuration, the variation of the force applied between the hammer and the ancillary was analyzed and an indicator I was determined based on the impact momentum of the signal. The simulated results are compared to the experiments. The value of the polar gap decreases with the impact velocity and increases with the interference fit. The bone–implant contact area was significantly correlated with the resonance frequency (R 2 = 0.94) and the indicator (R 2 = 0.95). The results show the potential of impact analyses to retrieve the bone–implant contact properties.
-
Ex Vivo Evaluation of Cementless Acetabular Cup Stability Using Impact Analyses with a Hammer Instrumented with Strain Sensors
2017Co-Authors: Antoine Tijou, Philippe Hernigou, Giuseppe Rosi, Charles-henri Flouzat-lachaniette, Guillaume HaiatAbstract:The Acetabular Cup (AC) implant stability is determinant for the success of cementless hip arthroplasty. A method based on the analysis of the impact force applied during the press-fit insertion of the AC implant using a hammer instrumented with a force sensor was developed to assess the AC implant stability. The aim of the present study was to investigate the performance of a method using a hammer equipped with strain sensors to retrieve the AC implant stability. Different AC implants were inserted in five bovine samples with different stability conditions leading to 57 configurations. The AC implant was impacted 16 times by the two hammers consecutively. For each impact; an indicator I S (respectively I F) determined by analyzing the time variation of the signal corresponding to the averaged strain (respectively force) obtained with the stress (respectively strain) hammer was calculated. The pull-out force F was measured for each configuration. F was significantly correlated with I S (R 2 = 0.79) and I F (R 2 = 0.80). The present method has the advantage of not modifying the shape of the hammer that can be sterilized easily. This study opens new paths towards the development of a decision support system to assess the AC implant stability.
Thom E Snijders - One of the best experts on this subject based on the ideXlab platform.
-
the effect of postural pelvic dynamics on the three dimensional orientation of the Acetabular Cup in tha is patient specific
2021Co-Authors: Thom E Snijders, Tom P C Schlosser, Rene M Castelein, Rob Stevenson, Harry Weinans, Marijn Van Straalen, Arthur De GastAbstract:Background Sagittal pelvic dynamics mainly consist of the pelvis rotating anteriorly or posteriorly while the hips flexes, and this affects the femoroAcetabular or THA configuration. Thus far, it is unknown how the Acetabular Cup of the THA in the individual patient reorients with changing sagittal pelvic dynamics. Questions/purposes The aim of this study was to validate a method that establishes the three-dimensional (3-D) Acetabular Cup orientation with changing sagittal pelvic dynamics and describe these changes during functional pelvic dynamics. Methods A novel trigonometric mathematical model, which was incorporated into an easy-to-use tool, was tested. The model connected sagittal tilt, transverse version, and coronal inclination of the Acetabular Cup during sagittal pelvic tilt. Furthermore, the effect of sagittal pelvic tilt on the 3-D reorientation of Acetabular Cups was simulated for Cups with different initial positions. Twelve pelvic CT images of patients who underwent THA were taken and rotated around the hip axis to different degrees of anterior and posterior sagittal pelvic tilt (± 30°) to simulate functional pelvic tilt in various body positions. For each simulated pelvic tilt, the transverse version and coronal inclination of the Cup were manually measured and compared with those measured in a mathematical model in which the 3-D Cup positions were calculated. Next, this model was applied to different Acetabular Cup positions to simulate the effect of sagittal pelvic dynamics on the 3-D orientation of the Acetabular Cup in the coronal and transverse plane. After pelvic tilt was applied, the intraclass correlation coefficients of 108 measured and calculated coronal and transverse Cup orientation angles were 0.963 and 0.990, respectively, validating the clinical use of the mathematical model. Results The changes in 3-D Acetabular Cup orientation by functional pelvic tilt differed substantially between Cups with different initial positions; the change in transverse version was much more pronounced in Cups with low coronal inclination (from 50° to -29°) during functional pelvic tilt than in Cups with a normal coronal inclination (from 39° to -11°) or high coronal inclination (from 31° to 2°). However, changes in coronal inclination were more pronounced in Acetabular Cups with high transverse version. Conclusion Using a simple algorithm to determine the dynamic 3-D reorientation of the Acetabular Cup during functional sagittal pelvic tilt, we demonstrated that the 3-D effect of functional pelvic tilt is specific to the initial Acetabular Cup orientation and thus per THA patient. Clinical relevance Future studies concerning THA (in)stability should not only include the initial Acetabular Cup orientation, but also they need to incorporate the effect of sagittal pelvic dynamics on the individual 3-D Acetabular Cup orientation. Clinicians can also use the developed tool, www.3d-hip.com, to calculate the Acetabular Cup's orientation in other instances, such as for patients with spinopelvic imbalance.
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations versus stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations versus 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P=.039). Compared to controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. In contrast, the transverse version, was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of evidence Diagnostic, Level III;
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of Evidence Diagnostic, Level III.
-
trigonometric algorithm defining the true three dimensional Acetabular Cup orientation correlation between measured and calculated Cup orientation angles
2018Co-Authors: Thom E Snijders, Tom P C Schlosser, Rene M Castelein, Harry Weinans, S M Van Gaalen, A De GastAbstract:Background Acetabular Cup orientation plays a key role in implant stability and the success of total hip arthroplasty. To date, the orientation has been measured with different imaging modalities and definitions, leading to lack of consensus on optimal Cup placement. A 3-dimensional (3D) concept involving a trigonometric description enables unambiguous definitions. Our objective was to test the validity and reliability of a 3D trigonometric description of Cup orientation. Methods Computed tomographic scans of the pelvis, performed for vascular assessment of 20 patients with 22 primary total hip replacements in situ, were systematically collected. On multiplanar reconstructions, 3 observers independently measured Cup orientation retrospectively in terms of coronal inclination, sagittal tilt, and transverse version. The angles measured in 2 planes were used to calculate the angle in the third plane via a trigonometric algorithm. For correlation and reliability analyses, intraobserver and interobserver differences between measured and calculated angles were evaluated with use of the intraclass correlation coefficient (ICC). Results Measured and calculated angles had ICCs of 0.953 for coronal inclination, 0.985 for sagittal tilt, and 0.982 for transverse version. Intraobserver and interobserver reliability had ICCs of 0.987 and 0.987, respectively, for coronal inclination; 0.979 and 0.981, respectively, for sagittal tilt; and 0.992 and 0.978, respectively, for transverse version. Conclusions The 3D concept with its trigonometric algorithm is a valid and reliable tool for the measurement of Cup orientation. Clinical relevance By calculating the transverse version of Cups from coronal inclination and sagittal tilt measurements, the trigonometric algorithm enables a 3D definition of Cup orientation, regardless of the imaging modality used. In addition, it introduces sagittal tilt that, like pelvic tilt, rotates around the transverse axis.
Harry Weinans - One of the best experts on this subject based on the ideXlab platform.
-
the effect of postural pelvic dynamics on the three dimensional orientation of the Acetabular Cup in tha is patient specific
2021Co-Authors: Thom E Snijders, Tom P C Schlosser, Rene M Castelein, Rob Stevenson, Harry Weinans, Marijn Van Straalen, Arthur De GastAbstract:Background Sagittal pelvic dynamics mainly consist of the pelvis rotating anteriorly or posteriorly while the hips flexes, and this affects the femoroAcetabular or THA configuration. Thus far, it is unknown how the Acetabular Cup of the THA in the individual patient reorients with changing sagittal pelvic dynamics. Questions/purposes The aim of this study was to validate a method that establishes the three-dimensional (3-D) Acetabular Cup orientation with changing sagittal pelvic dynamics and describe these changes during functional pelvic dynamics. Methods A novel trigonometric mathematical model, which was incorporated into an easy-to-use tool, was tested. The model connected sagittal tilt, transverse version, and coronal inclination of the Acetabular Cup during sagittal pelvic tilt. Furthermore, the effect of sagittal pelvic tilt on the 3-D reorientation of Acetabular Cups was simulated for Cups with different initial positions. Twelve pelvic CT images of patients who underwent THA were taken and rotated around the hip axis to different degrees of anterior and posterior sagittal pelvic tilt (± 30°) to simulate functional pelvic tilt in various body positions. For each simulated pelvic tilt, the transverse version and coronal inclination of the Cup were manually measured and compared with those measured in a mathematical model in which the 3-D Cup positions were calculated. Next, this model was applied to different Acetabular Cup positions to simulate the effect of sagittal pelvic dynamics on the 3-D orientation of the Acetabular Cup in the coronal and transverse plane. After pelvic tilt was applied, the intraclass correlation coefficients of 108 measured and calculated coronal and transverse Cup orientation angles were 0.963 and 0.990, respectively, validating the clinical use of the mathematical model. Results The changes in 3-D Acetabular Cup orientation by functional pelvic tilt differed substantially between Cups with different initial positions; the change in transverse version was much more pronounced in Cups with low coronal inclination (from 50° to -29°) during functional pelvic tilt than in Cups with a normal coronal inclination (from 39° to -11°) or high coronal inclination (from 31° to 2°). However, changes in coronal inclination were more pronounced in Acetabular Cups with high transverse version. Conclusion Using a simple algorithm to determine the dynamic 3-D reorientation of the Acetabular Cup during functional sagittal pelvic tilt, we demonstrated that the 3-D effect of functional pelvic tilt is specific to the initial Acetabular Cup orientation and thus per THA patient. Clinical relevance Future studies concerning THA (in)stability should not only include the initial Acetabular Cup orientation, but also they need to incorporate the effect of sagittal pelvic dynamics on the individual 3-D Acetabular Cup orientation. Clinicians can also use the developed tool, www.3d-hip.com, to calculate the Acetabular Cup's orientation in other instances, such as for patients with spinopelvic imbalance.
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations versus stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations versus 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P=.039). Compared to controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. In contrast, the transverse version, was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of evidence Diagnostic, Level III;
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of Evidence Diagnostic, Level III.
-
trigonometric algorithm defining the true three dimensional Acetabular Cup orientation correlation between measured and calculated Cup orientation angles
2018Co-Authors: Thom E Snijders, Tom P C Schlosser, Rene M Castelein, Harry Weinans, S M Van Gaalen, A De GastAbstract:Background Acetabular Cup orientation plays a key role in implant stability and the success of total hip arthroplasty. To date, the orientation has been measured with different imaging modalities and definitions, leading to lack of consensus on optimal Cup placement. A 3-dimensional (3D) concept involving a trigonometric description enables unambiguous definitions. Our objective was to test the validity and reliability of a 3D trigonometric description of Cup orientation. Methods Computed tomographic scans of the pelvis, performed for vascular assessment of 20 patients with 22 primary total hip replacements in situ, were systematically collected. On multiplanar reconstructions, 3 observers independently measured Cup orientation retrospectively in terms of coronal inclination, sagittal tilt, and transverse version. The angles measured in 2 planes were used to calculate the angle in the third plane via a trigonometric algorithm. For correlation and reliability analyses, intraobserver and interobserver differences between measured and calculated angles were evaluated with use of the intraclass correlation coefficient (ICC). Results Measured and calculated angles had ICCs of 0.953 for coronal inclination, 0.985 for sagittal tilt, and 0.982 for transverse version. Intraobserver and interobserver reliability had ICCs of 0.987 and 0.987, respectively, for coronal inclination; 0.979 and 0.981, respectively, for sagittal tilt; and 0.992 and 0.978, respectively, for transverse version. Conclusions The 3D concept with its trigonometric algorithm is a valid and reliable tool for the measurement of Cup orientation. Clinical relevance By calculating the transverse version of Cups from coronal inclination and sagittal tilt measurements, the trigonometric algorithm enables a 3D definition of Cup orientation, regardless of the imaging modality used. In addition, it introduces sagittal tilt that, like pelvic tilt, rotates around the transverse axis.
Lawrence D Dorr - One of the best experts on this subject based on the ideXlab platform.
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations versus stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations versus 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P=.039). Compared to controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. In contrast, the transverse version, was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of evidence Diagnostic, Level III;
-
the effect of functional pelvic tilt on the three dimensional Acetabular Cup orientation in total hip arthroplasty dislocations
2021Co-Authors: Thom E Snijders, Nathanael Heckmann, Tom P C Schlosser, Taro Tezuka, Rene M Castelein, Rob Stevenson, Harry Weinans, Arthur De Gast, Lawrence D DorrAbstract:Abstract Background Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-Acetabular positions. This case-control study compares changes in 3-D Acetabular Cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs. Methods Standing and sitting 3-D Cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D Cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position. Results The standing Cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P Conclusions Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional Cup orientation. Level of Evidence Diagnostic, Level III.
