Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development?

This article and any supplementary material should be cited as follows: Smit G, Bongers RM, Van der Sluis CK, Plettenburg DH. Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development? J Rehabil Res Dev. 2012;49(4):523–34.http://dx.doi.org/10.1682/JRRD.2011.07.0125

Slideshow ProjectDOI:10.1682/JRRD.2011.07.0125JSP

Efficiency of voluntary opening hand and hook prosthetic devices:

24 years of development?Gerwin Smit, MSc; Raoul M. Bongers, MSc, PhD;

Corry K. Van der Sluis, MD, PhD; Dick H. Plettenburg, MSc, PhD



• Aim– Objectively evaluate mechanical performance of

adult-size voluntary opening (VO) prosthetic terminal devices and select best tested device.

– Consider whether VO devices have improved in last 2 decades.

• Relevance– Help patients select appropriate devices.– Help manufacturers improve their designs.



Methods• Quantitatively tested

9 devices:– 4 hooks:

• Hosmer model 5XA.• Hosmer Sierra 2 Load VO.• RSL Steeper Carbon Gripper.• Otto Bock model 10A60.

– 5 hands:• Becker Imperial.• Hosmer Sierra VO.• Hosmer Soft VO.• RSL Steeper VO.• Otto Bock VO.

• Measured: – Pinch forces. – Activation forces.– Cable displacements.– Mass.– Opening span.

• Calculated work and hysteresis.

• Compared results with 1987 data.



Test set up. Cable activation force and displacement are measured. Fact = force activation cable, LVDT = linear variable differential transformer, mVact = voltage force sensor (unamplified), USB = universal serial bus, Vact = voltage force sensor (amplified), VLVDT = voltage displacement sensor, Xact = displacement activation cable.



Results• Hooks vs hands:– Hooks required lower

activation forces and delivered higher pinch forces than hands.

• Activation forces:– Very high for several

devices.

• Pinch forces:– Too low for all tested

hands.

• Best hook:– Hosmer model 5XA

hook with three bands.

• Best hand:– Hosmer Sierra VO hand.



Conclusions

• We found no improvements in VO devices compared with data from 1987.

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Efficiency of voluntary opening hand and hook prosthetic devices: 24 years of development?