Importance of Proximal A2 and A4 Pulleys to Maintaining Kinematics in the Hand: A Biomechanical Study

Chow, James C.Y.; Sensinger, Jon; McNeal, David W.; Chow, Bettina; Amirouche, Farid; Gonzalez, Mark H.

doi:10.1007/s11552-013-9547-0

Cited by 24 publications

(14 citation statements)

References 10 publications

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“…We observed that the centrally located annular pulleys A 2 and A 4 result in very high exion ranges (Tab. 2), thus agreeing with Dy and Daluiski (2013) and Chow et al (2014). Role of exible-inelastic biological C-pulleys is evident from sig-(a) Role of exible-inelastic C-pulleys and their heights: ℎ = ℎ 0 .…”

Section: The Biological Tendon Pulley Systemsupporting

confidence: 76%

“…Annular pulleys are sti , while cruciate pulleys are exible but inextensible. Pulleys A 2 and A 4 are the most important for full range exion (Dy and Daluiski (2013); Chow et al (2014)). PP -proximal phalange, IP -intermediate phalange, DP -distal phalange.…”

Section: Introductionmentioning

confidence: 99%

“…comfort in nger movement (Schweizer (2008)). Some cadaver studies suggest that smaller width of A 2 and A 4 pulleys can be used without compromising much on the exion range (Mitsionis et al (1999); Chow et al (2014); Lee ang and Coert ( 2014)). Those by Solonen and Hoyer (1967) and Hume et al (1991) that employ computational models contradict on the e ect of change in pulley positions.…”

Section: Introductionmentioning

confidence: 99%

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Comprehending finger flexor tendon pulley system using a computational analysis

Khatik,

Nishad,

Saxena

2020

Preprint

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Existing prosthetic/orthotic designs are rarely based on kinetostatics of a biological nger, especially its tendon-pulley system (TPS) which helps render a set of extraordinary functionalities. Studies on computational models or cadaver experiments do exist. However, they provide little information on TPS con gurations that lead to lower tendon tension, bowstringing, and pulley stresses, all of which a biological nger may be employing after all. A priori knowledge of such con gurations and associated trade-o s is helpful not only from the design viewpoint of, say, an exoskeleton but also for surgical reconstruction procedures. We present a parametric study to determine optimal TPS con gurations for the exor mechanism. A compliant, exure-based computational model is developed and simulated using the pseudo rigid body method, with various combinations of pulley/tendon attachment point locations, pulley heights, and widths. Deductions are drawn from the data collected to recommend the most suitable con guration. Many aspects of the biological TPS con guration are explained through the presented analysis. We reckon that the analytical approach herein will be useful in arriving at customized (optimized) hand exoskeletal designs.

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Section: The Biological Tendon Pulley Systemsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comprehending finger flexor tendon pulley system using a computational analysis

Khatik,

Nishad,

Saxena

2020

Preprint

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“…Surgical reconstruction of the A4 pulley is only advocated in cases of multilevel pulley injuries and outcomes seem to be disappointing. As Chow et al 7 have shown in cadaveric testing, insufficiency of the proximal A4 pulley has considerable effects on the range of motion of the proximal interphalangeal joint (PIP) joint, whereas effects on metacarpophalangeal joint or distal interphalangeal joint (DIP) joints were not significant. The functional integrity of the pulley system can be shown by physiological E-space, ensuring system efficiency.…”

Section: Methodsmentioning

confidence: 99%

Acute A4 Pulley Reconstruction with a First Extensor Compartment Onlay Graft

Jakubietz

Meffert

Schmidt

et al. 2017

Plastic and Reconstructive Surgery - Global Open

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Background:The integrity of the flexor tendon pulley apparatus is crucial for unimpaired function of the digits. Although secondary reconstruction is an established procedure in multi-pulley injuries, acute reconstruction of isolated, closed pulley ruptures is a rare occurrence. There are 3 factors influencing the functional outcome of a reconstruction: gapping distance between tendon and bone (E-space), bulkiness of the reconstruction, and stability. As direct repair is rarely done, grafts are used to reinforce the pulley. An advantage of the first extensor retinaculum graft is the synovial coating providing the possibility to be used both as a direct graft with synovial coating or as an onlay graft after removal of the synovia when the native synovial layer is present.Methods:A graft from the first dorsal extensor compartment is used as an onlay graft to reinforce the sutured A4 pulley. This technique allows reconstruction of the original dimensions of the pulley system while stability is ensured by anchoring the onlay graft to the bony insertions of the pulley.Results:Anatomical reconstruction can be achieved with this method. The measured E-space remained 0 mm throughout the recovery, while the graft incorporated as a slim reinforcement of the pulley, displaying no bulkiness.Conclusions:The ideal reconstruction should provide synovial coating and sufficient strength with minimal bulk. Early reconstruction using an onlay graft offers these options. The native synovial lining is preserved and the graft is used to reinforce the pulley.

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“…55 Proximal partial pulley excision may have a greater effect on digit range of motion than distal partial pulley excision. 56 To avoid the sequelae of A2 resection, reduction flexor tenoplasty has been reported. 57 Other authors have suggested "venting" of the A2 and A4 pulleys, either to facilitate repair or allow free gliding of the flexor tendons.…”

Section: Triggeringmentioning

confidence: 99%