Recurrent patellar dislocations in adolescents result in decreased knee flexion during the entire gait cycle

Spring brake orthosis (SBO) concentrates purely on the knee to generate the swing phase of the paraplegic gait with the required hip flexion occurring passively as a consequence of the ipsilateral knee flexion, generated by releasing the torsion spring mounted at the knee joint. Electrical stimulation then drives the knee back to full extension, as well as restores the spring potential energy. In this paper, genetic algorithm (GA) and its variant multi-objective GA (MOGA) is used to perform the search operation for the ‘best’ spring parameters for the SBO spring mounted on an average sized subject simulated in the sagittal plane. Conventional torsion spring is tested against constant torque type spring in terms of swing duration as, based on first principles, it is hypothesized that constant torque spring would be able to produce slower SBO swing phase as might be preferred in assisted paraplegic gait. In line with the hypothesis, it is found that it is not possible to delay the occurrence of the flexion peak of the SBO swing phase further than its occurrence in the natural gait. The use of conventional torsion spring causes the swing knee flexion peak to appear rather faster than that of the natural gait, resulting in a potentially faster swing phase and hence gait cycle. The constant torque type spring on the other hand is able to stretch duration of the swing phase to some extent, rendering it the preferable spring type in SBO.

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On Transfemoral Prosthetic Knee Design for Natural Human Knee Motion

Recent Patents on Mechanical Engineering ◽

10.2174/2212797613666191219154947 ◽

2020 ◽

Vol 13 (1) ◽

pp. 49-59

Author(s):

Wen-Tzong Lee ◽

Kevin Russell ◽

Raj S. Sodhi

Keyword(s):

Design Process ◽

Knee Flexion ◽

Gait Cycle ◽

Design Method ◽

Human Gait ◽

Motion Generation ◽

Knee Motion ◽

Human Knee ◽

Prosthetic Knee ◽

Position Data

Background: A transfemoral prosthetic knee is an artificial knee used by above-the-knee amputees. There are two major categories of transfemoral prosthetic knee designs: pin joint-based and polycentric designs. While pin joint-based knee designs only allow pure rotation of the knee, polycentric knee designs allow a combination of rotational and translational knee motion which is exhibited in natural knee motion. Objective: This work presents both the recently-patented design process and the resulting design of a polycentric transfemoral prosthetic knee that approximates natural spatial human knee motion during flexion and extension. Methods: The design process includes tibial motion acquisition, Revolute-Revolute-Spherical-Spherical linkage (or RRSS) motion generation, RRSS linkage axode generation and circle fitting. The polycentric transfemoral prosthetic knee design produced from this process includes a gear joint with a specific spatial orientation to approximate natural spatial human knee motion. Results: Using the design process, a polycentric transfemoral prosthetic knee was designed to replicate a group of five tibial positions over 37.5° of knee flexion (the amount of knee flexion in a standard human gait cycle) with a minimal structural error. Conclusion: The circular gear-based knee design accurately replicated natural spatial knee motion over the tibial position data given for a standard human gait cycle. The knee design method must be implemented over a broader sampling of tibial position data to determine if a circular gear-based knee design is consistently accurate.

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A Biologically Inspired Knee Actuator for a KAFO

Journal of Medical Devices ◽

10.1115/1.4033009 ◽

2016 ◽

Vol 10 (4) ◽

Cited By ~ 2

Author(s):

Feng Tian ◽

Mohamed Samir Hefzy ◽

Mohammad Elahinia

Keyword(s):

Knee Joint ◽

Knee Flexion ◽

Gait Cycle ◽

Knee Extension ◽

Lateral Side ◽

Walking Gait ◽

Normal Knee ◽

Knee Stiffness ◽

Control Knee ◽

Stiffness Profile

Knee–ankle–foot orthoses (KAFOs) are prescribed to improve abnormal ambulation caused by quadriceps weakness. There are three major types of KAFOs: passive KAFOs, semidynamic KAFOs, and dynamic KAFOs. Dynamic KAFOs are the only type that enables to control knee motions throughout the entire walking gait cycle. However, those available in the market are heavy, bulky, and have limited functionality. The UT dynamic KAFO is developed to allow knee flexion and assist knee extension over the gait cycle by using a superelastic nitinol actuator, which has the potential to reduce volume and weight and reproduce normal knee behavior. In order to match the normal knee stiffness profile, the dynamic actuator consists of two actuating parts that work in the stance and swing phases, respectively. Each actuating part combines a superelastic torsional rod and a torsional spring in parallel. Geometries of the two superelastic rods were determined by matlab-based numerical simulations. The simulation response of the dynamic actuator was compared with the normal knee stiffness, verifying that the proposed design is able to mimic the normal knee performance. The surrounding parts of the dynamic knee joint have then been designed and modeled to house the two actuating parts. The dynamic knee joint was fabricated and mounted on a conventional passive KAFO, replacing its original knee joint on the lateral side. Motion analysis tests were conducted on a healthy subject to evaluate the feasibility of the UT dynamic KAFO. The results indicate that the UT dynamic KAFO allows knee flexion during the swing phase of gait and provides knee motion close to normal.

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The Effect of Baclofen on the Gait of Hemiplegic Children Assessed by Means of Polarised Light Goniometry

Scottish Medical Journal ◽

10.1177/003693308002500441 ◽

1980 ◽

Vol 25 (4) ◽

pp. S29-S35 ◽

Cited By ~ 4

Author(s):

Adrian M. B. Minford ◽

J. Keith Brown ◽

Robert A. Minns ◽

P. Frazer ◽

L. Hollway ◽

...

Keyword(s):

Side Effects ◽

Clinical Improvement ◽

Knee Flexion ◽

Nocturnal Enuresis ◽

Gait Cycle ◽

Child Behaviour ◽

Functional Improvement ◽

Slight Improvement ◽

Concentration Difficulty ◽

Polarised Light

Gait was assessed by polarised light goniometry in 15 hemiplegic children aged 4−15 years. After initial clinical and goniometric assessment, baclofen 5−10 mg/day was started and increased over 4−6 weeks to a dose of 1−1.5 mg/kg/day. Assessment was repeated one week later. A statistically significant decrease in hip and knee flexion at the ‘toe-off’ phase of the gait cycle was found in both legs. Of the nine children who showed most change in goniometric assessment, five showed an obvious clinical improvement, two a slight improvement, one no change and one child's gait deteriorated. Of six children with minimal or no change goniometrically, four showed no change clinically, one minimal clinical improvement and one a deterioration clinically. Side effects included transient sedation (seven children), concentration difficulty (one child), behaviour disturbance (1 child) and nocturnal enuresis (three children). We concluded that although baclofen causes functional improvement in some hemiplegic children, its use should be carefully supervised in view of possible side effects and possible deterioration in gait.

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INVESTIGATION ON THE EFFECTS INDUCED BY TKA FEATURES ON TIBIO-FEMORAL MECHANICS PART I: FEMORAL COMPONENT DESIGNS

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519415400345 ◽

2015 ◽

Vol 15 (02) ◽

pp. 1540034 ◽

Cited By ~ 7

Author(s):

BERNARDO INNOCENTI ◽

HÉCTOR ROBLEDO YAGÜE ◽

RAQUEL ALARIO BERNABÉ ◽

SILVIA PIANIGIANI

Keyword(s):

Knee Flexion ◽

Gait Cycle ◽

Motor Task ◽

Literature Study ◽

Element Analysis ◽

J Curve ◽

Flexion Extension ◽

Total Knee ◽

Kinematics And Kinetics ◽

Single Radius

The lack of awareness of the exact number of instantaneous centers of knee flexion/extension rotation leads to the presence in the market of total knee arthroplasty (TKA) femoral components designed under different hypotheses. Although single radius (SR) designs are thought to replicate the physiological behavior in a more realistic way, surgeons do not always agree about the veracity of their theoretical advantages with respect to the multiple radii components (J-curve (JC) design). Apart from clinical studies, up to now, any literature study biomechanically and exhaustively compares these two TKA solutions, thus a finite element analysis (FEA) has been carried out. In particular, two models were defined to analyze the performance of a SR design and a JC design with the same tibial component during gait cycle and squat motor task. Tibio-femoral kinematics and kinetics have been investigated comparing the resulting contact area between components, internal–external (IE) rotation, position and magnitude of the center of total forces due to contact pressure and polyethylene von Misses stresses. Results demonstrate that, for low demanding tasks, there are no significant differences between the two designs, however, during the squat motor task, some changes in contact force and increases in polyethylene stress were identified for the SR solution.

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Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

Methods of Information in Medicine ◽

10.1055/s-0038-1636852 ◽

1997 ◽

Vol 36 (04/05) ◽

pp. 372-375 ◽

Cited By ~ 9

Author(s):

J. R. Sutton ◽

A. J. Thomas ◽

G. M. Davis

Keyword(s):

Spinal Cord ◽

Heart Rate ◽

Spinal Cord Injury ◽

Cardiac Output ◽

Electrical Stimulation ◽

Knee Flexion ◽

Flexion Extension ◽

Cord Injury ◽

Leg Exercise ◽

Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

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Effect of Manipulation under Anesthesia of the First Knee in Staged Bilateral Total Knee Arthroplasty on Clinical Outcome and Satisfaction

The Journal of Knee Surgery ◽

10.1055/s-0040-1709675 ◽

2020 ◽

Author(s):

Jung-Won Lim ◽

Yong-Beom Park ◽

Dong-Hoon Lee ◽

Han-Jun Lee

Keyword(s):

Total Knee Arthroplasty ◽

Patient Satisfaction ◽

Clinical Outcome ◽

Clinical Outcomes ◽

Knee Arthroplasty ◽

Knee Flexion ◽

Functional Score ◽

Manipulation Under Anesthesia ◽

Total Knee

AbstractThis study aimed to evaluate whether manipulation under anesthesia (MUA) affect clinical outcome including range of motion (ROM) and patient satisfaction after total knee arthroplasty (TKA). It is hypothesized that MUA improves clinical outcomes and patient satisfaction after primary TKA. This retrospective study analyzed 97 patients who underwent staged bilateral primary TKA. MUA of knee flexion more than 120 degrees was performed a week after index surgery just before operation of the opposite site. The first knees with MUA were classified as the MUA group and the second knees without MUA as the control group. ROM, Knee Society Knee Score, Knee Society Functional Score, Western Ontario and McMaster Universities (WOMAC) score, and patient satisfaction were assessed. Postoperative flexion was significantly greater in the MUA group during 6 months follow-up (6 weeks: 111.6 vs. 99.8 degrees, p < 0.001; 3 months: 115.9 vs. 110.2 degrees, p = 0.001; 6 months: 120.2 vs. 117.0 degrees, p = 0.019). Clinical outcomes also showed similar results with knee flexion during 2 years follow-up. Patient satisfaction was significantly high in the MUA group during 12 months (3 months: 80.2 vs. 71.5, p < 0.001; 6 months: 85.8 vs. 79.8, p < 0.001; 12 months: 86.1 vs. 83.9, p < 0.001; 24 months: 86.6 vs. 85.5, p = 0.013). MUA yielded improvement of clinical outcomes including ROM, and patient satisfaction, especially in the early period after TKA. MUA in the first knee could be taken into account to obtain early recovery and to improve patient satisfaction in staged bilateral TKA.

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