Assessing the accuracy and precision of manual registration of both femur and tibia using EOS imaging system with multiple views

1. Introduction The EOS imaging system produces two simultaneous X-rays of a subject. Both views are used for the generation of a sub- ject-specific 3D skeletal model. This model then allows to obtain quantitative parameters concerning the morphology and the positioning of bones. Furthermore, thanks to the low dose of the EOS imaging, it is possible to take several stereoradiographies of the same subjects in order to study different positions of the fem- oro-patellar joint (Dagneaux et al. 2014) or to analyze different positions of the subjects. Also, it can be a way to compare tibia and femur relative positions without and with an orthotic device such as a brace for example. For that, the 3D model, obtained from the reference standing position, is registered across the different pairs of X-rays for the other positions. The goals of this study are 1/ to evaluate the reproducibility of the registration of both in vitro and in vivo and 2/ to a o assess the accuracy of this manual method using in vitro data

3D Sequential Kinematics of the Femoro-Tibial Joint of Normal Knee from Multiple Bi-planar X-rays: Accuracy and Repeatability

Background: Several methods can be used to assess joint kinematics going from optoelectronic motion analysis to biplanar fluoroscopy. The aim of the present work was to evaluate the reliability of the use of biplane radiography to quantify the sequential 3D kinematics of the femoro-tibial joint. Methods: Bi-planar X-rays (EOS imaging) of 12 lower limbs (6 specimens in vitro and 6 subjects in vivo) were taken for various knee flexion angles. 3D personalized models of the femur and the tibia were registered on each pair ofviews. To quantify the bias, the kinematic parameters calculated from the registered models were compared to those obtained from the tripods embedded in the specimens. Intra and inter-operator repeatability of each parameter were assessed from the registrations made by 3 operators in vivo. Results: In vitro, the bias of the tibia pose estimation obtained from the registration method was inferior to 1.6 mm and 0.4◦. In vivo, the repeatability of the sequential kinematic parameters was inferior to 0.3◦, 2.1◦and 1.8◦, for respectively flexion, varus-valgus and medial-lateral rotation and inferior to 1.8 mm for translations. Conclusion: Compared to simple fluoroscopy, the accuracy of our method based on sequential images was of the same order of magnitude, with better results for the translation in the frontal plane. The low dose of radiation of the EOS system offers promising prospects for a clinical use of this method to assess the femoro-tibial sequential kinematics

Estimation of subject-specific ligament length variation during knee flexion

Detailed knowledge about subject-specific knee ligament length variation during knee flexion is crucial for musculoskel- etal modeling in human movement analysis and in clinical con- texts (Ascani et al. 2014). In this respect, accurate estimation of ligament origin and insertion locations is needed. Although extensive literature exists describing the ligament attachment site position ex vivo (Kopf et al. 2009), this information is hardly obtainable in vivo unless using medical imaging tech- niques (magnetic resonance, MRI, or computed tomography, CT) that are time- onsuming, expensive and, when radiation is involved, risky for the subjects. Furthermore, the identifica- tion of the ligament attachment site location using MRI may be characterized by significant inter- and intra-observer variabil- ity thus leading to errors that are too large to generate reliable subject-specific knee models (Rachmat et al. 2014). Therefore, the aim of the present study is to propose and validate a method for the accurate in vivo estimation of the subject-specific length of the major knee ligaments (anterior and posterior cruciate, ACL and PCL, medial and collateral ligaments, MCL and LCL) which does not necessarily require the use of medical imaging techniques to identify the ligament attachment sites

Isometric point of lateral femoral condyle analysis with in vitro kinematic study in order to position the extra-articular part of an ACL reconstruction

The anterior cruciate ligament (ACL) injury leads to an anterior laxity associated with a variable rotational laxity. Without any treatment, this lesion can have functional consequences (instability, disturbance of sport activities or even everyday life activities) and anatomic ones (meniscal or cartilaginous lesions) (Dejour et al. 2004). However, ACL reconstruction can fail in 5–30% of the cases (Dejour et al. 2004, 2014; Bignozzi et al. 2009), because of a recurrence of laxity or a residual rotational laxity. The extra-articular tenodesis associated with an intra-articular plasty (Khiami et al. 2013) is supposed to control the rotational laxity, but the precise positioning on the lateral femoral condyle is not well defined.The objective of this study is to determine the isometric point on the lateral side of the lateral femoral condyle relatively to the Gerdy’s Tubercle with an in vitro kinematic 3D study.This work was funded by the SOFCOT (SOciete Francaise de Chirurgie Orthopedique et Traumatologique

A new method for the evaluation of the end-to-end distance of the knee ligaments and popliteal complex during passive knee flexion

Background: Accurate knowledge about the length variation of the knee ligaments (ACL, PCL, MCL and LCL) and the popliteal complex during knee flexion/extension is essential for modelling and clinical applications. The aimof the present study is to provide this information by using an original technique able to faithfully reproduce the continuous passive knee flexion–extension kinematics and to reliably identify each ligament/tendon attachment site. Methods: Twelve lower limbs (femur, tibia, fibula, patella)were tested and set inmotion (0–120°) using an ad hoc rig. Tibio-femoral kinematics was obtained using an optoelectronic system. A 3D digital model of each bone was obtained using low-dosage stereoradiography. Knee specimens were dissected and the insertion of each ligament and popliteal complex were marked with radio opaque paint. ACL, PCL and MCL were separated into two bundles. Bone epiphyses were CT-scanned to obtain a digital model of each ligament insertion. Bones and attachment site models were registered and the end-to-end distance variation of each ligament/tendon was computed over knee flexion. Results: A tibial internal rotation of 18°±4° with respect to the femur was observed. The different bundles of the ACL, MCL and LCL shortened, whereas all bundles of the PCL lengthened. The popliteal complex was found to shorten until 30° of knee flexion and then to lengthen. Conclusion: The end-to-end distance variation of the knee ligaments and popliteal complex can be estimated during knee flexion using a robust and reliable method based on marking the ligaments/tendon insertions with radiopaque paint. Level of evidence: Level IVThanks to Ann-Laure Pollastri for her technical support and to Louis Dagneaux for helping during the experimental session. The authors also thank the ParisTech BiomecAM chair program on subject-specific musculoskeletal modelling. This research was approved by the ethics committee of the human anatomy lab of the University of Caen (Basse Normandie, France)

Femur, tibia and fibula bone templates to estimate subject-specific knee ligament attachment site locations

In-vivo estimates of the positions of knee ligament attachment sites are crucial for subject-specific knee modelling. The present study provides template digital models of femur, tibia and fibula that embed the positions of centroids of the origins and insertions of cruciate and collateral ligaments, along with information on their dispersion related to inter-individual variability. By using a shape transformation procedure of choice, these templates can be made to match anatomical information measured on a subject under analysis. Generic bone digital models of the femur, tibia and fibula were first chosen as bone templates. Ligament attachment areas were accurately identified through dissection on the bones of 11 knee specimens, and marked using radio opaque paint. Digital models of these bones embedding the positions of the centroids of the identified ligament attachment areas were thereafter obtained using medical imaging techniques. These centroids were mapped onto the relevant bone template, thus obtaining a cloud of 11 points for each attachment site, and descriptive statistics of the position of these points were thereafter determined. Dispersion of these positions, essentially due to inter-individual variability, was below 6 mm for all attachment areas. The accuracy with which subject-specific ligament attachment site positions may be estimated using the bone template models provided in this paper was also assessed using the above-mentioned 11 specimens data set, and a leave-one-out cross validation approach. Average accuracy was found to be 3.3±1.5 mm and 5.8±2.9 mm for femoral and tibial/fibular attachment sites, respectively.The contribution of Ann-Laure Pollastri and of LouisDagneaux is gratefully acknowledged.The authors also thank theParisTech BiomecAM chair program on subject-specific musculoskeletal modelling, with the support of COVEA and Société Général

Modélisation informatique du genou (étude de la cinématique, de la longueur et de la tension des ligaments au cours d'une flexion)

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Enquête sur les connaissances, les atitudes et les moyens de prévention vis-à-vis du dopage sportif au niveau des pharmacies d'officine

LYON1-BU Santé (693882101) / SudocRENNES1-BU Santé (352382103) / SudocSudocFranceF

Successful Pelvic Resection for Acetabular Hydatidosis

Background. Hydatidosis of the bone is a rare occurrence (0.9 to 2.5% of all localization of the disease). In those occurrences, the pelvic bone is the second most frequent localization. Curative treatment of pelvic bone hydatidosis is difficult and a consensus is yet to be found. Clinical Case. We report a case of hydatidosis of the ischium, extended to the homolateral hip. The patient was treated through hip resection using patient-specific cutting guides, followed by total hip reconstruction. Albendazole was administered to the patient for two months before the surgery and for three months following the surgery. Conclusions. In a young patient, hydatidosis of the pelvic bone can be treated with satisfying results through wide resection of the hip coupled with an antiparasitic treatment administered before and after the surgery. Prosthetic reconstruction, similar to what is done in cancer surgery, restores good functions