title: In vivo recruitment patterns in the anterior oblique and dorsoradial ligaments of the first carpometacarpal joint.
abstract: The anterior oblique ligament (AOL) and the dorsoradial ligament (DRL) are both regarded as mechanical stabilizers of the thumb carpometacarpal (CMC) joint, which in older women is often affected by osteoarthritis. Inferences on the potential relationship of these ligaments to joint pathomechanics are based on clinical experience and studies of cadaveric tissue, but their functions has been studied sparsely in vivo. The purpose of this study was to gain insight into the functions of the AOL and DRL using in vivo joint kinematics data. The thumbs of 44 healthy subjects were imaged with a clinical computed tomography scanner in functional-task and thumb range-of-motion positions. The origins and insertion sites of the AOL and the DRL were identified on the three-dimensional bone models and each ligament was modeled as a set of three fibers whose lengths were the minimum distances between insertion sites. Ligament recruitment, which represented ligament length as a percentage of the maximum length across the scanned positions, was computed for each position and related to joint posture. Mean AOL recruitment was lower than 91% across the CMC range of motion, whereas mean DRL recruitment was generally higher than 91% in abduction and flexion. Under the assumption that ligaments do not strain by more than 10% physiologically, our findings of mean ligament recruitments across the CMC range of motion indicate that the AOL is likely slack during most physiological positions, whereas the DRL may be taut and therefore support the joint in positions of CMC joint abduction and flexion.
authors.affiliation: Center for Biomedical Engineering and School of Engineering, Brown University, Providence, RI 02912, United States.
authors.forename: Eni
authors.initials: E
authors.lastname: Halilaj
authors.affiliation: Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada K7L 3N6.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rainbow
authors.affiliation: Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI 02903, United States.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Moore
authors.affiliation: Department of Computer Science, Brown University, Providence, RI 02912, United States.
authors.forename: David H
authors.initials: DH
authors.lastname: Laidlaw
authors.affiliation: Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI 02903, United States.
authors.forename: Arnold-Peter C
authors.initials: AP
authors.lastname: Weiss
authors.affiliation: Robert A. Chase Hand & Upper Limb Center, Department of Ortho paedic Surgery, Stanford University, Stanford, CA 94304, United States.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Ladd
authors.affiliation: Center for Biomedical Engineering and School of Engineering, Brown University, Providence, RI 02912, United States; Department of Orthopaedics, The Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI 02903, United States. Electronic address: joseph_crisco@brown.edu.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Crisco
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D052737:Carpometacarpal Joints / Q000000981:diagnostic imaging* / Q000502:physiology; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008022:Ligaments / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009068:Movement; D010003:Osteoarthritis / Q000000981:diagnostic imaging; D016059:Range of Motion, Articular; D013314:Stress, Mechanical; D013933:Thumb / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: Anterior oblique ligament; Dorsoradial ligament; In vivo; Ligament modeling; Thumb carpometacarpal joint