Automatic joint alignment measurements in pre- and post-operative long leg standing radiographs

A whole leg radiograph is not necessary for postoperative determination of the mechanical leg axis after total knee arthroplasty

BACKGROUND

Anteroposterior (AP) whole leg radiographs (WLR) in the standing position for assessment of the mechanical leg axis are generally performed preoperatively for the planning of total knee replacement (TKR) and postoperatively to assess the leg axis. The objective of the present study was to investigate whether, if preoperative WLR are available, postoperative AP standard knee radiographs in the standing position are sufficient for calculating the mechanical leg axis.

METHODS

In the present prospective study, the mechanical and the anatomical leg axes were determined on the basis of WLR from 104 patients prior to implantation of a TKR and the difference was calculated. Twelve weeks postoperatively, standing long AP radiographs and WLR were prepared. In addition, the mechanical axis was calculated by adding the preoperative difference between the anatomical and mechanical axis to the anatomical axis from the postoperative AP radiographs. Accuracy, bias and level of agreement for calculated relative to measured mechanical alignment were determined.

RESULTS

Mean accuracy of calculated mechanical alignment was 0.5° ± 0.4°, and mean bias was 0.0° ± 0.6° (p = 1.00). Bland-Altman analysis revealed a 95% upper and lower level of agreement of - 1.3° and 1.3°, respectively.

CONCLUSION

A preoperative WLR and a postoperative long AP knee standard radiograph are sufficient to determine the mechanical leg axis after TKR. If these are available, it is possible to do without WLR after TKR, particularly since they involve higher radiation exposure, are time-consuming, and are also prone to errors in the first postoperative weeks.

LEVEL OF EVIDENCE

II diagnostic study.

ACL Reconstruction Decision Support. Personalized Simulation of the Lachman Test and Custom Activities

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on "Methodologies, Models and Algorithms for Patients Rehabilitation".

OBJECTIVES

The objective of the proposed approach is to develop a clinical decision support system (DSS) that will help clinicians optimally plan the ACL reconstruction procedure in a patient specific manner.

METHODS

A full body model is developed in this study with 23 degrees of freedom and 93 muscles. The knee ligaments are modeled as non-linear spring-damper systems and a tibiofemoral contact model was utilized. The parameters of the ligaments were calibrated based on an optimization criterion. Forward dynamics were utilized during simulation for predicting the model's response to a given set of external forces, posture configuration and physiological parameters.

RESULTS

The proposed model is quantified using MRI scans and measurements of the well-known Lachman test, on several patients with a torn ACL. The clinical potential of the proposed framework is demonstrated in the context of flexion-extension, gait and jump actions. The clinician is able to modify and fine tune several parameters such as the number of bundles, insertion position on the tibia or femur and the resting length that correspond to the choices of the surgical procedure and study their effect on the biomechanical behavior of the knee.

CONCLUSION

Computational knee models can be used to predict the effect of surgical decisions and to give insight on how different parameters can affect the stability of the knee. Special focus has to be given in proper calibration and experimental validation.

From bed to bench: bridging from informatics practice to theory: an exploratory analysis

BACKGROUND

In 2009, Applied Clinical Informatics (ACI)--focused on applications in clinical informatics--was launched as a companion journal to Methods of Information in Medicine (MIM). Both journals are official journals of the International Medical Informatics Association.

OBJECTIVES

To explore which congruencies and interdependencies exist in publications from theory to practice and from practice to theory and to determine existing gaps. Major topics discussed in ACI and MIM were analyzed. We explored if the intention of publishing companion journals to provide an information bridge from informatics theory to informatics practice and vice versa could be supported by this model. In this manuscript we will report on congruencies and interdependences from practice to theory and on major topics in MIM.

METHODS

Retrospective, prolective observational study on recent publications of ACI and MIM. All publications of the years 2012 and 2013 were indexed and analyzed.

RESULTS

Hundred and ninety-six publications were analyzed (ACI 87, MIM 109). In MIM publications, modelling aspects as well as methodological and evaluation approaches for the analysis of data, information, and knowledge in biomedicine and health care were frequently raised - and often discussed from an interdisciplinary point of view. Important themes were ambient-assisted living, anatomic spatial relations, biomedical informatics as scientific discipline, boosting, coding, computerized physician order entry, data analysis, grid and cloud computing, health care systems and services, health-enabling technologies, health information search, health information systems, imaging, knowledge-based decision support, patient records, signal analysis, and web science. Congruencies between journals could be found in themes, but with a different focus on content. Interdependencies from practice to theory, found in these publications, were only limited.

CONCLUSIONS

Bridging from informatics theory to practice and vice versa remains a major component of successful research and practice as well as a major challenge.

From bench to bed: bridging from informatics theory to practice. An exploratory analysis

BACKGROUND

In 2009, the journal Applied Clinical Informatics (ACI) commenced publication. Focused on applications in clinical informatics, ACI was intended to be a companion journal to METHODS of Information in Medicine (MIM). Both journals are official journals of IMIA, the International Medical Informatics Association.

OBJECTIVES

To explore, after five years, which congruencies and interdependencies exist in publications of these journals and to determine if gaps exist. To achieve this goal, major topics discussed in ACI and in MIM had to be analysed. Finally, we wanted to explore, whether the intention of publishing these companion journals to provide an information bridge from informatics theory to informatics practice and from practice to theory could be supported by this model. In this manuscript we will report on congruencies and interdependencies from practise to theory and on major topis in ACI. Further results will be reported in a second paper.

METHODS

Retrospective, prolective observational study on recent publications of ACI and MIM. All publications of the years 2012 and 2013 from these journals were indexed and analysed.

RESULTS

Hundred and ninety-six publications have been analysed (87 ACI, 109 MIM). In ACI publications addressed care coordination, shared decision support, and provider communication in its importance for complex patient care and safety and quality. Other major themes included improving clinical documentation quality and efficiency, effectiveness of clinical decision support and alerts, implementation of health information technology systems including discussion of failures and succeses. An emerging topic in the years analyzed was a focus on health information technology to predict and prevent hospital admissions and managing population health including the application of mobile health technology. Congruencies between journals could be found in themes, but with different focus in its contents. Interdependencies from practise to theory found in these publications, were only limited.

CONCLUSIONS

Bridging from informatics theory to practise and vice versa remains a major component of successful research and practise as well as a major challenge.