Introduction
What is OrthoLoad?
OrthoLoad is a public database containing the loads acting in orthopaedic implants. They were measured in vivo using instrumented implants with telemetric data transmission. Currently load data are available for the
Hip joint, shoulder joint, knee joint, vertebral body replacement and internal spinal fixator.
Data is presented as videos, containing the time-dependent forces and moments, force vectors, video images of the patients activity and numerical data. Many results involving the ‘Hip Joint’ are already available in the database. More data are continuously added from the actual ‘Hip Joint III’ where also the three moments were measured. From hip and knee implants, only selected examples are available because access to this data must be detained until it has been published in scientific journals.
From the OrthoLoad database you can select an implant, an activity with parameters, a patient and one or several trials. The time course of the loads is shown in videos (encoded in the wmv- or mp4-format) and can be analyzed in more detail by displaying single video frames. Numerical data files (text files, suffix .akf) can additionally be downloaded and the forces and moments then be used in finite element studies or joint simulators, for example.
It’s recomended to run OrthoLoad on a Windows PCs with Media Player Classic, VLC Player or FairPlay Lite player or on Linux/Mac OS X with VLC Player!
How to use OrthoLoad?
Video
Enter DATABASE and in the top left frame ‘Joint Loads’ you can choose an ‘Implant’ type, an ‘Activity’, possibly an additional ‘Parameter’, a ‘Patient’ and a trial by ‘File Name’. Then an OrthoLoad video will be shown on the right frame ‘Now Selected’.
Alternatively you may select a trial directly by typing its basic trial number into the upper right frame ‘Select Video by File Name’. The basic trial number is the first part of the file name e.g. ‘s1r_211005_1_80′ of the file ‘s1r_211005_1_80_screen.mp4′
(s1r = shoulder patient #1 with implant at the right side, _211005 = date: October 21st 2005, _1_80 = internal trial number _screen = video file, _fmax = png-image)
Use the buttons in the top left frame ‘Joint Loads’ to play, show or download videos, data or pictures. You may just play the video in your browser with Flash Plug-in. Or you download and play the video on your computer with your standard video player. We clearly favour the ‘Media Player Classic’ or ‘VLC Player’ for MS Windows and ‘VLC Player’ for Mac OS X and Linux. Videos are encoded in the wmv or mp4(H.264) format.
The vertical marker line inside the force diagram shows the actual measuring time. All other data is displayed synchronously to this time (patient video, vectors, tables …).
The ‘Hip Joint’ was instrumented with a 4-channel telemetry transmitter and only the forces were measured, no moment diagram is shown. All other implants measure forces and moments with measuring units %BW and %BW*m. Using the patients’ body weight (BW), the values in N and Nm can be recalculated.
To show or download a data file *.akf belonging to the video *.wmv or *.mp4 use the buttons ‘Show’ or ‘Download’ in the top left frame ‘Joint Loads’.
‘Additional Data’ *.eof, *.cof etc. synchronized to the video file is available for some trials
Measurements
A coil for the inductive power supply is arranged around the implant and the antenna is placed close to it. The data received is at first controlled in regard to transmission errors and then led to a notebook where the forces and moments are calculated and displayed in real time. The images of the patients’ exercises and the synchronous data stream are both recorded on the same video tape. On a monitor or using a video beamer, the forces and moments can be controlled immediately. This allows one to detect unexpected loading situations and immediately modify the way an exercise is performed.
