title: In vivo analysis of trapeziometacarpal joint kinematics during pinch tasks.
abstract: This study investigated how the posture of the thumb while performing common pinch movements and the levels of pinch force applied by the thumb affect the arthrokinematics of the trapeziometacarpal joint in vivo. Fifteen subjects performed the pinch tasks at the distal phalange (DP), proximal interphalangeal (PIP) joint, and metacarpophalangeal (MP) joint of the index finger with 0%, 50%, and 80% of maximal pinch forces by a single-axis load cell. 3D images of the thumb were obtained using the computed tomography. The results show that the reference points moved from the central region to the dorsal-radial region when changing from pinching the DP to the MP joint without pinching force being applied. Pinching with 80% of the maximum pinching force resulted in reference points being the closest to the volar-ulnar direction. Significant differences were seen between 0% and 50% of maximum pinch force, as well as between 0% and 80%, when pinching the MP joint in the distal-proximal direction. The effects of posture of the thumb and applied pinch force on the arthrokinematics of the joint were investigated with a 3D model of the trapeziometacarpal joint. Pinching with more than 50% of maximum pinch force might subject this joint to extreme displacement.
authors.affiliation: Department of Occupational Therapy, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Li-Chieh
authors.identifier: 0000-0001-7728-0096
authors.initials: LC
authors.lastname: Kuo
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan ; Musculoskeletal Research Center, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Chien-Ju
authors.identifier: 0000-0001-9571-8610
authors.initials: CJ
authors.lastname: Lin
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Guan-Po
authors.initials: GP
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: I-Ming
authors.initials: IM
authors.lastname: Jou
authors.affiliation: Department of Radiology, National Cheng Kung University Hospital, Tainan 704, Taiwan.
authors.forename: Chien-Kuo
authors.identifier: 0000-0001-8887-2935
authors.initials: CK
authors.lastname: Wang
authors.affiliation: Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow 119526, Russia.
authors.forename: Irina G
authors.initials: IG
authors.lastname: Goryacheva
authors.affiliation: Institute of Mechanics, Lomonosov Moscow State University, Moscow 119992, Russia.
authors.forename: Marat Z
authors.initials: MZ
authors.lastname: Dosaev
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan ; Musculoskeletal Research Center, National Cheng Kung University, Tainan 701, Taiwan ; Medical Device Innovation Center, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Fong-Chin
authors.initials: FC
authors.lastname: Su
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D006801:Humans; D008297:Male; D008662:Metacarpophalangeal Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D052581:Pinch Strength / Q000502:physiology*; D013647:Task Performance and Analysis; D014057:Tomography, X-Ray Computed; D051222:Trapezium Bone / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult