scholarly journals DETERMINATION OF PATELLOFEMORAL JOINT REACTION FORCES AS A FUNCTION OF CADENCE DURING STEP EXERCISES 218

1997 ◽  
Vol 29 (Supplement) ◽  
pp. 38
Author(s):  
J. Smith ◽  
A. E. Greenwald ◽  
R. M. Greenwald
Keyword(s):  
Patellofemoral Joint ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

Comparison of Three-Dimensional Patellofemoral Joint Reaction Forces in Persons With and Without Patellofemoral Pain

2014 ◽  
Vol 30 (4) ◽  
pp. 493-500 ◽  
Author(s):  
Yu-Jen Chen ◽  
Christopher M. Powers
Keyword(s):  
Patellofemoral Joint ◽  
Three Dimensional ◽  
Patellofemoral Pain ◽  
Biomechanical Analysis ◽  
Control Group ◽  
Three Dimensional Model ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Magnetic Resonance Imaging Mri ◽  
Joint Reaction

The purpose of this study was to determine if persons with patellofemoral pain (PFP) exhibit differences in patellofemoral joint reaction forces (PFJRFs) during functional activities. Forty females (20 PFP, 20 controls) underwent two phases of data collection: (1) magnetic resonance imaging (MRI) and (2) biomechanical analysis during walking, running, stair ascent, and stair descent. A previously described three-dimensional model was used to estimate PFJRFs. Resultant PFJRFs and the orthogonal components were reported. The PFP group demonstrated lower peak resultant PFJRFs and posterior component and superior component of the PFJRFs compared with the control group across all conditions. However, the PFP group had a higher peak lateral component of the PFJRF in three out of the four conditions evaluated. The lower resultant PFJRFs suggested that individuals with PFP may employ strategies to minimize patellofemoral joint loading, but it did not result in diminished lateral forces acting on the patella.

Durability Test Method for Patella Implants

2007 ◽  
Author(s):  
L. Kirkpatrick ◽  
L. Borgstede ◽  
T. Johnson ◽  
J. Mason
Keyword(s):  
Soft Tissue ◽  
Knee Joint ◽  
Patellofemoral Joint ◽  
Point Contact ◽  
Test Method ◽  
Durability Test ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

Modeling and testing of the patello-femoral joint (PFJ) presents challenges in simulating the appropriate loading and kinematics. Walking is an activity of lower demand for patella performance. Higher demands occur during higher flexion activities such as stair ascending/descending, chair rising, and squatting. High patellofemoral joint reaction forces (PFJR) have been shown to begin around 60° of tibiofemoral flexion and remain high (2.5 × BW to 3.35 × BW) until approximately 110° of tibiofemoral (TF) flexion, at which point contact with soft tissue will tend to off-load the knee joint. Therefore, the flexion range of highest load for the patella is considered to be between 60° and 110° of TF flexion.

Quantification of Patellofemoral Joint Reaction Forces during Functional Activities Using a Subject-Specific Three-Dimensional Model

2010 ◽  
Vol 26 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Yu-Jen Chen ◽  
Irving Scher ◽  
Christopher M. Powers
Keyword(s):  
Patellofemoral Joint ◽  
Three Dimensional ◽  
Specific Model ◽  
Three Dimensional Model ◽  
Stair Ascent ◽  
Stair Descent ◽  
Subject Specific ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

The purpose of this study was to describe an imaging based, subject specific model that was developed to quantify patellofemoral joint reaction forces (PFJRF’s). The secondary purpose was to test the model in a group of healthy individuals while performing various functional tasks. Twenty healthy subjects (10 males, 10 females) were recruited. All participants underwent two phases of data collection: 1) magnetic resonance imaging of the knee, patellofemoral joint, and thigh, and 2) kinematic, kinetic and EMG analysis during walking, running, stair ascent, and stair descent. Using data obtained from MRI, a subject specific representation of the extensor mechanism was created. Individual gait data were used to drive the model (via an optimization routine) and three-dimensional vasti muscle forces and subsequent three-dimensional PFJRF’s were computed. The average peak PFJRF was found to be highest during running (58.2 N/kg-bwt), followed by stair ascent (33.9 N/kg-bwt), stair descent (27.9 N/kg-bwt), and walking (10.1 N/kg-bwt). No differences were found between males and females. For all conditions, the direction of the PFJRF was always in the posterior, superior, and lateral directions. The posterior component of the PFJRF always had the greatest magnitude, followed by superior and lateral components. Our results indicate that estimates of the magnitude and direction of the PFJRF during functional tasks can be obtained using a 3D-imaging based model.

Prediction of Antagonistic Muscle Forces Using Inverse Dynamic Optimization During Flexion/Extension of the Knee

1999 ◽  
Vol 121 (3) ◽  
pp. 316-322 ◽  
Author(s):  
G. Li ◽  
K. R. Kaufman ◽  
E. Y. S. Chao ◽  
H. E. Rubash
Keyword(s):  
Dynamic Optimization ◽  
Optimization Procedure ◽  
Muscle Forces ◽  
Inverse Dynamic ◽  
Optimization Criteria ◽  
Flexion Extension ◽  
Antagonistic Muscle ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Joint Reaction

This paper examined the feasibility of using different optimization criteria in inverse dynamic optimization to predict antagonistic muscle forces and joint reaction forces during isokinetic flexion/extension and isometric extension exercises of the knee. Both quadriceps and hamstrings muscle groups were included in this study. The knee joint motion included flexion/extension, varus/valgus, and internal/external rotations. Four linear, nonlinear, and physiological optimization criteria were utilized in the optimization procedure. All optimization criteria adopted in this paper were shown to be able to predict antagonistic muscle contraction during flexion and extension of the knee. The predicted muscle forces were compared in temporal patterns with EMG activities (averaged data measured from five subjects). Joint reaction forces were predicted to be similar using all optimization criteria. In comparison with previous studies, these results suggested that the kinematic information involved in the inverse dynamic optimization plays an important role in prediction of the recruitment of antagonistic muscles rather than the selection of a particular optimization criterion. Therefore, it might be concluded that a properly formulated inverse dynamic optimization procedure should describe the knee joint rotation in three orthogonal planes.

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