Using a 3D handheld scanner to capture trochlear groove shape: proof of concept study

Author(s):  
J Mistry ◽  
CB Hing ◽  
S Harris

Introduction Trochleoplasty is a surgical procedure used to treat patellar instability by modifying the trochlear groove. Analysis of the groove with a handheld scanner would enable accurate real-time planning and facilitate tailormade correction. We aimed to measure trochlear depth, sulcus angle, trochlear facet ratio, trochlear angle and lateral trochlear inclination angle and to establish inter- and intra-rater reliability for knee models to determine reliability and repeatability. Methods The trochlear grooves of three knee models were scanned by two investigators. Three-dimensional reference models were created and surface-matched. Custom software was used to determine the desired parameters. The intraclass correlation coefficient (ICC) was used to determine test–retest reliability and the parameter results for each model that showed best reproducibility. Results There was good interobserver reliability (trochlear depth, 1.0mm; sulcus angle, 2.7°; trochlear angle, 4.0°; lateral trochlear inclination angle, 4.0°), except in the trochlear facet ratio (32.0%) of one knee model. With outliers removed, the ICC was moderate to excellent in 73.34% of measurements, with trochlear depth showing the best reproducibility. Discussion This feasibility study showed a handheld scanner in conjunction with supporting software can measure trochlear parameters with good to excellent inter- and intra-observer reliability.

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
J Mistry ◽  
C Hing ◽  
S Harris

Abstract Introduction Trochleoplasty is a surgical procedure used to treat patellar instability through modifying the trochlear groove. Analysis of the groove with a hand-held scanner would enable accurate real time planning and facilitate tailor made correction. We aimed to measure trochlear depth, sulcus angle, trochlear facet ratio, trochlear angle and lateral trochlear inclination angle and establish inter- and intra-rater reliability for each knee model. Method The trochlear groove of the knee models was scanned by two investigators and 3D reference models created. These were surface matched and custom software along with Excel was utilised to determine the desired parameters. Intraclass correlation coefficient (ICC) was used for test-retest reliability and to determine which parameter results, for each model, showed the best reproducibility. Results There was good inter-observer reliability - trochlear depth (1.0 mm), sulcus angle (2.7°), trochlear angle (4.0°) and lateral trochlear inclination angle (4.0°), except in the trochlear facet ratio (32.0%) of one knee model. With outliers removed ICC was good-excellent in (46.7%) of measurements, with trochlear depth showing the best reproducibility. Conclusions This feasibility study showed that the hand-held scanner in conjunction with supporting software can measure trochlear parameters in a controlled environment and justifies extending research into its use in trochleoplasty.


2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Jianghui Qin ◽  
Dongyang Chen ◽  
Zhihong Xu ◽  
Dongquan Shi ◽  
Jin Dai ◽  
...  

Purpose.To determine whether the sulcus angle and the lateral to medial facet ratio correlate with patella lateral displacement and tilt in patients without patella instability.Methods.Computed tomography images of the lower limb of 64 patients without known arthropathy were collected. Three-dimensional models of the lower limb with a unified coordinate system were rebuilt by using Mimics software. The sulcus angle, lateral to medial facet ratio, lateral trochlear inclination of the patellar groove, tibial tuberosity-trochlear groove (TT-TG) distance, bisect offset index, and lateral tilt of the patella were measured. Pearson’s correlation test was used to determine the relationship between the aforementioned parameters.Results.Data from 51 patients were analyzed. The sulcus angle was negatively correlated with lateral tilt inclination (p<0.001,r=0.8406) and positively correlated with the bisect offset index (p=0.003,r=0.634) and patellar tilt (p=0.03,r=0.551); the lateral to medial facet ratio was positively correlated with TT-TG distance (p=0.003,r=0.643) and bisect offset index (p=0.026,r=0.559).Conclusion.The sulcus angle and lateral to medial facet ratio of the patellar groove can influence patella tracking in patients with stable knee joints.


Author(s):  
Ian S. MacLean ◽  
Taylor M. Southworth ◽  
Ian J. Dempsey ◽  
Neal B. Naveen ◽  
Hailey P. Huddleston ◽  
...  

AbstractThe tibial tubercle–trochlear groove (TT-TG) distance is currently utilized to evaluate knee alignment in patients with patellar instability. Sagittal plane pathology measured by the sagittal tibial tubercle–trochlear groove (sTT-TG) distance has been described in instability but may also be important to consider in patients with cartilage injury. This study aims to (1) describe interobserver reliability of the sTT-TG distance and (2) characterize the change in the sTT-TG distance with respect to changing knee flexion angles. In this cadaveric study, six nonpaired cadaveric knees underwent magnetic resonance imaging (MRI) studies at each of the following degrees of knee flexion: −5, 0, 5, 10, 15, and 20. The sTT-TG distance was measured on the axial T2 sequence. Four reviewers measured this distance for each cadaver at each flexion angle. Intraclass correlation coefficients were calculated to determine interobserver reliability and reproducibility of the sTT-TG measurement. Analysis of variance (ANOVA) tests and Friedman's tests with a Bonferroni's correction were performed for each cadaver to compare sTT-TG distances at each flexion angle. Significance was defined as p < 0.05. There was excellent interobserver reliability of the sTT-TG distance with all intraclass correlation coefficients >0.9. The tibial tubercle progressively becomes more posterior in relation to the trochlear groove (more negative sTT-TG distance) with increasing knee flexion. The sTT-TG distance is a measurement that is reliable between attending surgeons and across training levels. The sTT-TG distance is affected by small changes in knee flexion angle. Awareness of knee flexion angle on MRI is important when this measurement is utilized by surgeons.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 180
Author(s):  
William Suryajaya ◽  
Maria Purbiati ◽  
Nada Ismah

Background: Due to advances in digital technology, it is possible to obtain digital dental models through intraoral scanning. The stereolithographic data collected from the scanner can subsequently be printed into a three-dimensional dental model in resinic material. However, the accuracy between digital dental models and printed dental models needs to be evaluated since it might affect diagnosis and treatment planning in orthodontic treatment. This study aimed to evaluate the accuracy of digital models scanned by a Trios intraoral scanner and three-dimensional dental models printed using a Formlabs 2 3D printer in linear measurements and Bolton analysis. Methods: A total of 35 subjects were included in this study. All subjects were scanned using a Trios intraoral scanner to obtain digital study models. Stereolithographic data from previous scanning was printed using a Formlabs 2 3D printer to obtain printed study models. Mesiodistal, intercanine, intermolar, and Bolton analysis from all types of study models were measured. The intraclass correlation coefficient was used to assess intraobserver and interobserver reliability. All data were then statistically analyzed. Results: The reliability tests were high for both intraobserver and interobserver reliability, which demonstrates high reproducibility for all measurements on all model types. Most of the data compared between study models showed no statistically significant differences, though some data differed significantly. However, the differences are considered clinically insignificant. Conclusion: Digital dental models and three-dimensional printed dental models may be used interchangeably with plaster dental models for diagnostic and treatment planning purposes. Keywords: Accuracy, 3D printing, digital dental model, printed dental model.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 180
Author(s):  
William Suryajaya ◽  
Maria Purbiati ◽  
Nada Ismah

Background: Due to advances in digital technology, it is possible to obtain digital dental models through intraoral scanning. The stereolithographic data collected from the scanner can subsequently be printed into a three-dimensional dental model in resinic material. However, the accuracy between digital dental models and printed dental models needs to be evaluated since it might affect diagnosis and treatment planning in orthodontic treatment. This study aimed to evaluate the accuracy of digital models scanned by a Trios intraoral scanner and three-dimensional dental models printed using a Formlabs 2 3D printer in linear measurements and Bolton analysis. Methods: A total of 35 subjects were included in this study. All subjects were scanned using a Trios intraoral scanner to obtain digital study models. Stereolithographic data from previous scanning was printed using a Formlabs 2 3D printer to obtain printed study models. Mesiodistal, intercanine, intermolar, and Bolton analysis from all types of study models were measured. The intraclass correlation coefficient was used to assess intraobserver and interobserver reliability. All data were then statistically analyzed. Results: The reliability tests were high for both intraobserver and interobserver reliability, which demonstrates high reproducibility for all measurements on all model types. Most of the data compared between study models showed no statistically significant differences, though some data differed significantly. However, the differences are considered clinically insignificant. Conclusion: Digital dental models and three-dimensional printed dental models may be used interchangeably with plaster dental models for diagnostic and treatment planning purposes. Keywords: Accuracy, 3D printing, digital dental model, printed dental model.


2021 ◽  
Vol 9 (9) ◽  
pp. 232596712110282
Author(s):  
Gherardo Pagliazzi ◽  
Jutta M. Ellermann ◽  
Cathy S. Carlson ◽  
Kevin G. Shea ◽  
Elizabeth A. Arendt

Background: Understanding the morphology of cartilage/bony maturation in preadolescents may help explain adult trochlear variation. Purpose: To study trochlear morphology during maturation in children and infants using magnetic resonance imaging (MRI). Study Design: Descriptive laboratory study. Methods: Twenty-four pediatric cadaveric knees (10 male and 14 female knees; age, 1 month to 10 years) were included. High-resolution imaging of the distal femoral secondary ossification center was performed using 7-T or 9.4-T MRI scanners. Three-dimensional MRI scans were produced, and images were reformatted; 3 slices in the axial, sagittal, and coronal planes images were analyzed, with coronal and sagittal imaging used for image orientation. Biometric analysis included lateral and medial trochlear height (TH); cartilaginous sulcus angle (CSA); osseous sulcus angle (OSA); trochlear depth; and trochlear facet (TF) length symmetry. Sex comparisons were considered when ≥1 specimen from both sexes of the same age was available; these included 11 knees spanning 4 age groups (ages 1, 3, 4, and 7 years). Results: The analysis of trochlear morphology showed a lateral TH greater than the medial TH at all ages. The thickest cartilage was found on the lateral TF in the younger specimens. Regarding the development of osseous and cartilaginous trochlear contour, a cartilaginous sulcus was present in the 3-month-old specimen and continued to deepen up to the age of 4 years. The shape of the osseous center evolved from round (1 month) to oval (9 months) to rectangular (2 years); no distinct bony trochlear sulcus was present, although a well-formed cartilaginous sulcus was present. The first evidence of formation of a bony sulcus was at 4 years. By the age of 7 to 8 years, the bony contour of the adult distal femur resembled its cartilaginous contour. Female samples had a shallower CSA and OSA than did the male ones in all samples that had a defined OSA. Conclusion: Female trochlear grooves tended to be shallower (flatter). The lateral trochlea was higher (TH) and wider (TF length) during growth than was the medial trochlea in both sexes; furthermore, the development of the osseous sulcus shape lagged behind the development of the cartilaginous sulcus shape in the authors’ study population. Clinical Relevance: Bony anatomy of the trochlear groove did not match the cartilaginous anatomy in preadolescent children, suggesting that caution should be used when interpreting bony anatomy in this age group.


2020 ◽  
pp. 193229682097465
Author(s):  
Joel Willem Johan Lasschuit ◽  
Jill Featherston ◽  
Katherine Thuy Trang Tonks

Background: In an era of increasing technology and telehealth utilization, three-dimensional (3D) wound cameras promise reliable, rapid, and touch-free ulceration measurements. However, reliability data for commercially available devices in the diabetes foot service setting is lacking. We aimed to evaluate the reliability of diabetes-related foot ulceration measurement using a 3D wound camera in comparison to the routinely used ruler and probe. Method: Participants were prospectively recruited from a tertiary interdisciplinary diabetes foot service. Ulcerations were measured at each visit by two blinded observers, first by ruler and probe, and then using a 3D wound camera twice. Reliability was evaluated using intraclass correlation coefficients (ICC). Measurement methods were compared by Pearson correlation. Results: Sixty-three ulcerations affecting 38 participants were measured over 122 visits. Interobserver reliability of ruler measurement was excellent for estimated area (ICC 0.98, 95% CI 0.97-0.98) and depth (ICC 0.93, 95% CI 0.90-0.95). Intraobserver and interobserver reliability of the 3D wound camera area was excellent (ICC 0.96, 95%CI 0.95-0.97 and 0.97 95% CI 0.96-0.98, respectively). Depth was unrecordable in over half of 3D wound camera measurements, and reliability was inferior to probe measurement. Area correlation between methods was good ( R = 0.88 and 0.94 per observer); however, depth correlation was poor ( R = 0.49 and 0.65). Conclusions: 3D wound cameras offer practical advantages over ruler-based measurement. In diabetes-related foot ulceration, the reliability and comparability of area measurement was excellent across both methods, although depth was more reliably obtained by the probe. These limitations, together with cost, are important considerations if implementing this technology in diabetes foot care.


2020 ◽  
Vol 98 (10) ◽  
Author(s):  
Lena Friedrich ◽  
Joachim Krieter ◽  
Nicole Kemper ◽  
Irena Czycholl

Abstract The present study’s aim was to test a German guideline for farm’s self-monitoring in sows and piglets for its feasibility as well as its interobserver and test–retest reliability. The study was performed between September 2016 and April 2018 on 13 farrowing farms in Northern Germany. Contrary to the guideline, the testing was not carried out by the farmers themselves but by 2 observers with experience in pigs representing common farmers. For the interobserver reliability study, the observers performed 20 joint farm visits independently assessing the same animals. For the test–retest reliability study, each farm was visited 5 times by 1 observer (day 0, day 3, week 7, month 5, month 10). Farm visit 1 (day 0) was used as reference and compared with the remaining farm visits. The reliability was evaluated using Spearman’s rank correlation coefficient (RS), intraclass correlation coefficient (ICC), and limits of agreement (LoA). As results, the guideline’s feasibility was limited. The indicators’ reliability also presented divergent results: All indicators in piglets revealed acceptable to good interobserver reliability (RS 0.64 to 0.77 ICC 0.33 to 0.48 LoA between the intervals −0.02 to 0.13 and −0.02 to 0.00). Contrarily, interobserver reliability was low for indicators in sows (e.g., claw alterations: RS −0.41 ICC 0.00 LoA −0.97 to 0.68). Overall acceptable test–retest reliability could be assigned to all indicators although no exact agreement existed but only the pursuit of trends is indicated. On the basis of the present results, the guideline in its present form cannot be recommended for farms’ self-monitoring. Given the restricted applicability, it should be reconsidered whether it might not be more appropriate to use scientifically tested and generally accepted animal welfare assessment systems such as the Welfare Quality animal welfare assessment protocols, although their application is also time-consuming.


Author(s):  
Maury L. Hull ◽  
Stephen M. Howell

AbstractPatellofemoral complications following total knee arthroplasty can be traced in part to alignment of the femoral component. Kinematic alignment (KA) and mechanical alignment (MA) use the same femoral component but align the component differently. Our objective was to determine differences in trochlear morphology from native for a femoral component interfaced with an anatomical patellar prosthesis in KA and MA. Ten three-dimensional femur-cartilage models were created by combining computed tomography and laser scans of native human cadaveric femurs free of skeletal abnormalities. The femoral component was positioned using KA and MA. Measurements of the prosthetic and native trochlea were made along the arc length of the native trochlear groove and differences from native were computed for the medial-lateral and radial locations of the groove and sulcus angle. Mean medial-lateral locations of the prosthetic groove were within 1.5 and 3.5 mm of native for KA and MA, respectively. Mean radial locations of the prosthetic groove were as large as 5 mm less than native for KA and differences were greater for MA. Sulcus angles of the prosthetic trochlea were 10 degrees steeper proximally, and 10 degrees flatter distally than native for both KA and MA. Largest differences from native occurred for radial locations and sulcus angles for both KA and MA. The consistency of these results with those of other fundamentally different designs which use a modified dome (i.e., sombrero hat) patellar prosthesis highlights the need to reassess the design of the prosthetic trochlea on the part of multiple manufacturers worldwide.


Author(s):  
Bruna Marques de Almeida Saraiva ◽  
Thais Moraes de Vieira ◽  
Anderson Sales Alexandre ◽  
Geferson da Silva Araújo ◽  
Evandro Fornias Sperandio ◽  
...  

Abstract Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine that generates changes in the biomechanics of the rib cage. Digital photogrammetry enables the recording of subtle changes and the interrelationship between parts of the human body that are difficult to measure by other means. The aim of this study was to create angles and thoracic distances and to evaluate the interobserver and intraobserver reliability of these measurements using the Software de Avaliação Postural (SAPO) in patients with AIS. This cross-sectional study evaluated 30 individuals aged between 11 and 18 years with AIS. We used SAPO with the thoracic markers in the form of angles (A) and distances (D) with involves structures like acromion, manubrium, xiphoid process, lower angle of the scapula, last false rib, anterior iliac spine process. Two experienced observers (A and B) analyzed the photos and all followed the same routine of analysis. Intraobserver and interobserver reproducibility was assessed by the Bland-Altman plot and intraclass correlation coefficient (ICC), while intraobserver and interobserver reliability was assessed by the T-Test and Wilcoxon's Test. A high repeatability index was obtained among the evaluations, with twelve of the sixteen variables considered as reliable in all statistical tests. The interobserver analyzes presented excellent correlation coefficients (ICC), showing good reliability for six of the sixteen variables proposed. The SAPO method presented good reproducibility and reliability for most of the thoracic markers created, showing that photogrammetry may be a complementary tool in the evaluation of thoracic alterations in patients with AIS.


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