Biomechanical evaluation of wrist-driven flexor hinge orthosis in persons with spinal cord injury.
The wrist-driven flexor hinge orthosis (WDFHO) is a device used to restore hand function in persons with tetraplegic spinal cord injury by furnishing three-point prehension. We assessed the effectiveness and biomechanical properties of the WDFHO in 24 persons with cervical 6 or 7 tetraplegia who have severely impaired hand function. This study introduces a mechanical operating model to assess the efficiency of the WDFHO. Experimental results showed that pinch force increased significantly (p < 0.001) after using the WDFHO and was found to positively correlate with the strength of wrist extensor muscles (r = 0.41, p < 0.001). However, when the strength of the wrist extensors acting on the WDFHO was greater, the reciprocal wrist and finger motion that generates three-point prehension was less effective (r = 0.79, p < 0.001). Reliable and valid biomechanical evaluation of the WDFHO could improve our understanding of its biomechanics.
Department of Rehabilitation Medicine, Clinical Center, National Institutes of Health, Bethesda, MD.
Yeoun-Seung
YS
Kang
Yoon-Ghil
YG
Park
Bum-Suk
BS
Lee
Hyung-Soon
HS
Park
D000328:Adult; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae; D005260:Female; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology; D009989:Orthotic Devices; D052581:Pinch Strength; D011782:Quadriplegia / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation*; D013119:Spinal Cord Injuries / Q000150:complications / Q000503:physiopathology / Q000534:rehabilitation*; D055815:Young Adult
biomechanics; efficiency; finger motion; hand 
function; mechanical operating model; pinch force; spinal cord 
injury; three-point prehension; wrist extensor muscles; wrist-driven flexor hinge orthosis