Explainable Prediction of Whether The Acetabular Cup Is Placed in The “Safe Zone” from X-ray Images

2021 ◽  
Author(s):  
Fuchang Han ◽  
Shenghui Liao ◽  
Chao Xiong ◽  
Haitao Wei ◽  
Renzhong Wu ◽  
...  
Keyword(s):  
Safe Zone ◽  
Acetabular Cup ◽  
X Ray

scholarly journals Accuracy of cup placement in total hip arthroplasty by means of a mechanical positioning device: a comprehensive cadaveric 3d analysis of 16 specimens

2019 ◽  
pp. 112070001987482
Author(s):  
Arthur J Kievit ◽  
Johannes G G Dobbe ◽  
Wouter H Mallee ◽  
Leendert Blankevoort ◽  
Geert J Streekstra ◽  
...  
Keyword(s):  
3D Models ◽  
Safe Zone ◽  
3D Analysis ◽  
Anterior Pelvic Plane ◽  
Mechanical Device ◽  
Acetabular Cup ◽  
Anteversion Angle ◽  
Positioning Device ◽  
The Mean ◽  
Safe Zones

Introduction: We tested whether a mechanical device (such as Hipsecure) to pinpoint the anterior pelvic plane (APP) as a guide can improve acetabular cup placement. To assess accuracy we asked: (1) is the APP an effective guide to position acetabular cup placement within acceptable ° of divergence from the optimal 40° inclination and 15° anteversion; (2) could a mechanical device increase the number of acetabular cup placements within Lewinnek’s safe zone (i.e. inclination 30° to 50°; anteversion 5° to 25°)? Methods: 16 cadaveric specimens were used to assess the 3D surgical success of using a mechanical device APP to guide acetabular cup placement along the APP. We used the Hipsecure mechanical device to implant acetabular cups at 40° inclination and 15° anteversion. Subequently, all cadaveric specimens with implants were scanned with a CT and 3D models were created of the pelvis and acetabular cups to assess the outcome in terms of Lewinnek’s safe zones. Results: The mean inclination of the 16 implants was 40.6° (95% CI, 37.7–43.4) and the mean anteversion angle was 13.4° (95% CI, 10.7–16.1). All 16 cup placements were within Lewinnek’s safe zone for inclination (between 30° and 50°) and all but 2 were within Lewinnek’s safe zone for anteversion (between 5° and 25°). Conclusion: In cadaveric specimens, the use of a mechanical device and the APP as a guide for acetabular cup placement resulted in good positioning with respect to both of Lewinnek’s safe zones.

The synergetic effect of pelvic rotation and X-ray offset on radiographic angles of the acetabular cup

2019 ◽  
Vol 57 (11) ◽  
pp. 2359-2371
Author(s):  
Jing-Xin Zhao ◽  
Xiu-Yun Su ◽  
Zhe Zhao ◽  
Ruo-Xiu Xiao ◽  
Guo-Fei Sun ◽  
...  
Keyword(s):  
Synergetic Effect ◽  
Acetabular Cup ◽  
Pelvic Rotation ◽  
X Ray

Two-dimensional Morphological Characteristics of the Distal Radius on Axial Magnetic Resonance Image and the Effects on Distal Screw Length

2017 ◽  
Vol 22 (02) ◽  
pp. 167-173
Author(s):  
Ho Youn Park ◽  
Youn Tae Roh ◽  
Dong Uk Min ◽  
Seok Whan Song ◽  
Yoo Joon Sur
Keyword(s):  
Magnetic Resonance ◽  
Distal Radius ◽  
Magnetic Resonance Image ◽  
Morphological Characteristics ◽  
Safe Zone ◽  
Two Dimensional ◽  
X Ray ◽  
Screw Length ◽  
Hazard Zone ◽  
The Mean

Background: Detection of dorsal cortical penetration of distal locking screws is difficult owing to the irregular shape of the dorsal surface of the distal radius. This study was designed to analyze two-dimensional morphological characteristics of the distal radius on axial magnetic resonance image, and to suggest a guideline for evaluation of screw length in distal radius fractures on the fluoroscopic or plain X-ray true lateral image. Methods: Anteroposterior length and lateral width of the distal radius, distance between the highest and the lowest point of the dorsal cortex (deceptive length), and widths of the first to second (hazard zone) and the third to fifth extensor compartments (safe zone) at the Lister tubercle level were measured on 104 axial magnetic resonance images by two hand surgeons. Results: The mean length and width of the distal radius at the Lister tubercle level were 22.96 mm and 30.42 mm, respectively. The mean hazard zone and safe zone widths were 8.72 mm and 19.43 mm, respectively. The mean deceptive length was 4.07 mm and the deceptive length did not have a relationship with height, sex, and age of subjects. Conclusions: We suggest that 4 mm be used as a reference value for the evaluation screw length at the safe zone. If the vertical distance between a distal screw tip and the peak of the Lister tubercle is lesser than 4 mm on a fluoroscopic or plain X-ray true lateral image, dorsal cortical penetration should be suspected. When dorsal cortical penetration at the hazard zone is suspected, both oblique or pro-supination views should be checked.

Measuring anatomical acetabular cup orientation with a new X-ray technique

2006 ◽  
Vol 11 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Otto Müller ◽  
Patrik Reize ◽  
Dirk Trappmann ◽  
Nikolaus Wülker
Keyword(s):  
Acetabular Cup ◽  
X Ray

scholarly journals An Easy-to-Use Portable Ultrasound Based Device for the Measurement of the Pelvic Tilt

10.29007/pwhr ◽  
2018 ◽  
Author(s):  
Guillaume Dardenne ◽  
Jean-Philippe Pluchon ◽  
Aziliz Guezou-Philippe ◽  
Hoel Letissier ◽  
Chafiaa Hamitouche ◽  
...  
Keyword(s):  
Pelvic Tilt ◽  
Safe Zone ◽  
Individual Variability ◽  
Daily Activities ◽  
Patient Specific ◽  
Average Error ◽  
Portable Ultrasound ◽  
X Ray ◽  
Non Invasive ◽  
Specific Parameter

The orientation of the cup in Total Hip Arthroplasty plays a major role on the post- operative results. It has been considered for several decades that the cup should be oriented according to the safe zone defined by Lewinnek. However, this safe zone is not always suitable because of the inter-individual variability of the pelvic tilt during daily activities. We propose in this paper a non-invasive ultrasound based solution which can easily measure this patient specific parameter in order to thereafter otimise the cup orientation. The accuracy of this system was assessed with a specific pelvic phantom. A clinical pilot study was also performed on ten patients. The pelvic tilt was measured in three daily positions: the supine, sitting and standing positions. The average error was 1.15°±0.82°. The average pelvic tilt was -97.1°±28.6°, -46.3°±12.8° and -9.0°±8.3° for respectively the supine, the sitting and the standing positions. The high inter-individual variability of the pelvic tilt in different daily positions highlight the need to have a suitable device for the measurement of this patient specific parameter for THA. The proposed system is easy-to-use, portable and allows the pelvic tilt measurement in different positions without any additional x-ray radiation.

scholarly journals Evaluation of the feasibility of acetabular cup pre-determination in revision total hip arthroplasty via X-ray of the bone stock of the anterosuperior acetabulum

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jingwei Zhang ◽  
Keyu Kong ◽  
Yingjun Chi ◽  
Xiaoliang Liu ◽  
Yiming Zeng ◽  
...  
Keyword(s):  
Contact Line ◽  
Primary Stability ◽  
Roc Curves ◽  
Line Length ◽  
Contact Length ◽  
Bone Stock ◽  
Acetabular Cup ◽  
X Ray ◽  
Revision Tha ◽  
Cage Group

Abstract Purpose This study was aimed to explore (1) location on AP pelvic X-ray that displayed bone stock in anterosuperior acetabulum; (2) whether X-ray could provide enough evidence to evaluate whether bone stock could provide support for acetabular cup; (3) criteria to determine whether anterosuperior bone stock could provide sufficient support for cup on X-ray. Methods Our study retrospectively collected 43 patients who underwent revision THA for cup loosening from 2014 to 2019. The position of anterosuperior acetabular bone stock was compared between X-ray and CT-based 3-D reconstruction. Seventy-millimeter acetabular cup was implanted simulatively to obtain the contact line between acetabular cup and superolateral remaining bone stock. The contact line length and the angle were measured. Patients were divided into cup group and cage group, and ROC curves of both contact line length and angle were drawn. Results The superolateral part of acetabulum on X-ray could reflect the anterosuperior host bone stock of acetabulum according to the comparison of anteroposterior pelvic X-ray and 3-D reconstruction. Critical point was chosen when we got the highest sensitivity with a 100% specificity in ROC curves. The critical values of contact length and angle were 15.58 mm and 25.5°. Conclusions Surgeons could assess the anterosuperior bone stock of acetabulum by AP pelvic X-ray to decide whether revision could be done merely using cup or need customized cage. Clinically, when contact line length was larger than 16 mm or contact angle was larger than 25.5°, adoption of cup could obtain primary stability in the revision surgery in most cases.

scholarly journals Accuracy of Image-less Navigation for Functional Cup Positioning in Total Hip Arthroplasty

10.29007/3lbz ◽  
2019 ◽  
Author(s):  
Morteza Meftah ◽  
Vinnay Siddappa ◽  
Jeffery Muir ◽  
Peter White
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Weight Bearing ◽  
Safe Zone ◽  
Computer Assisted ◽  
Acetabular Cup ◽  
Assisted Navigation ◽  
Total Hip ◽  
Significant Difference ◽  
Cup Positioning

Computer-assisted navigation has the potential to improve the accuracy of cup positioning during total hip arthroplasty (THA) and prevent leg length discrepancy (LLD). The purpose of this study was to compare acetabular cup position and post- operative LLD after primary THA using posterolateral approach. Between August 2016 to December 2017, 57 THAs using imageless navigation were matched with 57 THA without navigation, based on age, gender and BMI. Post-operative weight-bearing radiographs were assessed using for anteversion, inclination and LLD. Goal for functional cup placement was 40° inclination and 20° anteversion based on preoperative weight bearing pelvic images. Functional LLD was measured as compared to pre- operative radiographs and contralateral side. Proportion of cups within Lewinnek’s safe zone, proximity to a pre-operative target of and the LLD >5 mm was assessed. The mean age was 54.9 ± 9.6 years (30 – 72) and 57.6 ± 12.5 years (20 – 85) in control and navigated groups, respectively. Mean cup orientation in the navigated group was 20.6°± 3.3° (17 - 25) of anteversion and 41.9°± 4.8° (30 - 51) of inclination, vs. 25.0°± 11.1° (10 - 31) and 45.7°± 8.7° (29 – 55) in control group, where were statistically significant (p=0.005 and p=0.0001), respectively. In the navigated group, significantly more acetabular cups were placed within Lewinnek’s safe zone (anteversion: 78% vs. 47%, p=0.005; inclination: 92% vs. 67%, p=0.002). There was no significant difference in mean LLD in navigation and control groups (3.1 ± 1.5 mm vs. 4.6 ± 3.4 mm, p=0.36), although fewer LLDs >5 mm were reported in the navigated group (7.1%) than in controls (31.4%, p=0.007). The use of this image-less computer-assisted navigation improved the accuracy with which acetabular cup components were placed and may represent an important method for limiting post-operative complications related to cup malpositioning and LLD.

Erratum to: Central X-ray beam correction of radiographic acetabular cup measurement after THA: an experimental study

2017 ◽  
Vol 12 (5) ◽  
pp. 839-839 ◽  
Author(s):  
T. Schwarz ◽  
M. Weber ◽  
M. Wörner ◽  
T. Renkawitz ◽  
J. Grifka ◽  
...  
Keyword(s):  
Experimental Study ◽  
Acetabular Cup ◽  
X Ray

scholarly journals Accuracy of acetabular cup placement using an angle-adjusting alignment guide with laser pointer in total hip arthroplasty

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902096286
Author(s):  
Yusuke Okanoue ◽  
Koji Aso ◽  
Junpei Dan ◽  
Shogo Takaya ◽  
Masashi Izumi ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Safe Zone ◽  
The Novel ◽  
Laser Pointer ◽  
Acetabular Cup ◽  
Total Hip ◽  
Experienced Surgeon ◽  
Inexperienced Surgeon ◽  
Alignment Guide

Purpose: To evaluate cup-positioning accuracy in total hip arthroplasty (THA) using a novel angle-adjusting alignment guide with laser pointer and determine whether level of surgical experience affects accuracy of cup placement or not. Methods: We included 117 hips in 104 patients who underwent THA using the novel guide. We retrospectively reviewed 44 hips in 40 patients who underwent THA before the novel guide was introduced. We compared differences in cup angles between the novel guide group and the conventional guide group as well as the discrepancies in targeted angles between the experienced surgeon group and the inexperienced surgeon group. Results: There were 114/117 hips (97.4%) within the Lewinnek safe zone in the novel guide group and 32/44 hips (72.7%) within the safe zone in the conventional guide group. There were significantly fewer outliers in the novel guide group ( p < 0.001). In the experienced surgeon group, the mean absolute errors in inclination and anteversion were 2.0 ± 1.7° and 2.1 ± 2.3°, respectively; which were not significantly different from those in the inexperienced surgeon group (2.3 ± 2.1° and 2.8 ± 2.3°, respectively). Conclusion: The novel angle-adjusting alignment guide with laser pointer is a simple tool that provides better accuracy of cup position than that obtained using conventional guides. Accurate cup placement is possible using the novel guide, regardless of surgeons’ experience.

scholarly journals Well-Placed Acetabular Component Oriented Outside the Safe Zone During Weight-Bearing Daily Activities

2021 ◽  
Vol 9 ◽  
Author(s):  
Nan Zheng ◽  
Xiangjun Hu ◽  
Dimitris Dimitriou ◽  
Kerong Dai ◽  
Tao Guo ◽  
...  
Keyword(s):  
Acetabular Component ◽  
Mechanical Performance ◽  
Weight Bearing ◽  
Safe Zone ◽  
Daily Activities ◽  
Acetabular Anteversion ◽  
Acetabular Cup ◽  
Acetabular Orientation ◽  
Level Walking

Background: A comprehensive and thorough understanding of functional acetabular component orientation is essential for optimizing the clinical outcome after total hip arthroplasty (THA). This study aimed to quantify the functional acetabular anteversion and inclination of unilateral THA patients during walking and static standing and to determine whether the functional acetabular orientation falls within the Lewinnek safe zone.Methods: Seventeen patients with unilateral THA received a CT scan and dual fluoroscopic imaging during level walking and static standing to evaluate in vivo hip kinematics. The pelvic functional coordinate system of the 3D CT-based computer model was defined by the line of gravity and anterior pelvic plane (APP) to measure functional acetabular anteversion and inclination in different postures. The Lewinnek safe zone was used to determine the acetabular malposition during functional activities.Results: The THA side demonstrated an average of 10.1° (± 9.6°, range –7.5° to 29.9°) larger functional anteversion and 16.0° (± 9.2°, range –7.2° to 29.9°) smaller inclination than native hips during level walking. Functional acetabular anteversion in the THA side during level walking and static standing was significantly larger than anatomical measurements (p &lt; 0.05). Acetabular orientation of most well-placed THA components anatomically in the Lewinnek safe zone fell outside the safe zone during more than half of the gait cycle and static standing.Conclusion: The current study revealed that an anatomically well-placed acetabular cup does not guarantee a well-functional orientation during daily activities. The in vivo mechanical performance and loading conditions of the THA component during other weight-bearing activities should be investigated in further studies.

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