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In vivo loads acting at the hip joint have so far only been measured in few patients and without detailed documentation of gait data. Such information is required to test and improve wear, strength and fixation stability of hip implants. Measurements of hip contact forces with instrumented implants and synchronous analyses of gait patterns and ground(More)
Knowledge of the loads to which orthopedic implants are subjected is a fundamental prerequisite for their optimal biomechanical design, long-term success, and improved rehabilitation outcomes. In vivo load measurements are more accurate than those obtained using mathematical musculoskeletal models. An inductively powered integrated circuit inside the(More)
Detailed knowledge about loading of the knee joint is essential for preclinical testing of implants, validation of musculoskeletal models and biomechanical understanding of the knee joint. The contact forces and moments acting on the tibial component were therefore measured in 5 subjects in vivo by an instrumented knee implant during various activities of(More)
The Delft Shoulder and Elbow Model (DSEM), a large-scale musculoskeletal model, is used for the estimation of muscle and joint reaction forces in the shoulder and elbow complex. Although the model has been qualitatively verified using EMG-signals, quantitative validation has until recently not been feasible. The development of an instrumented shoulder(More)
This paper aims to develop an EMG-driven model of the shoulder that can consider possible muscle co-contractions. A musculoskeletal shoulder model (the original model) is modified such that measured EMGs can be used as model-inputs (the EMG-driven model). The model is validated by using the in-vivo measured glenohumeral-joint reaction forces (GH-JRFs).(More)
Loading of the spine is still not well understood. The most reliable results seemed to come from the intradiscal pressure measurements from studies by Nachemson, 1966. A new similar study by Wilke et al. (1999) complemented the present study and confirmed some of the earlier data, although it contradicted others. The new data did not confirm that the load(More)
Only little knowledge exists concerning the loads on internal spinal fixation devices during walking. In this study, forces and moments were measured in two patients using telemeterized spinal fixators. Although implant loads differed strongly before and after anterior fusion as well as between the two patients, some results were consistent. In every test(More)
The aim here was to define realistic load conditions for hip implants, based on in vivo contact force measurements, and to see whether current ISO standards indeed simulate real loads. The load scenarios obtained are based on in vivo hip contact forces measured in 4 patients during different activities and on activity records from 31 patients. The load(More)
STUDY DESIGN Disc pressure and fixator load were measured in an in vitro setup and compared to in vivo measurements with the identical transducers from the two groups participating in this study. OBJECTIVES The goal of this in vitro study was to determine the magnitude of trunk muscle forces during flexion and extension. The loading conditions in this(More)
In some diseases affecting only 1 hip joint, it is necessary to keep the contact force between femoral head and acetabulum (hip joint force) permanently low at the affected side. Six subjects were examined while they were walking and carrying a load in 1 or 2 hands. It was determined how the forces in both hip joints are influenced by the magnitude of the(More)