Bioengineering Laboratory - Research: Upper Extremity Function & Rehabilitation
| 3-D Multi-Articular Models Of The Carpus |
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The stability and function of the wrist depends on both the intercarpal ligaments and the bony articulations since there are no substantial muscles that insert on the carpus. There is limited data on the in vivo function of the carpal ligaments because accurately tracking both bone and soft tissue movement simultaneously using current imaging modalities is still a challenge. Therefore, we are working on computational methods to model both cartilage contact and ligament strains using cartilage thickness maps and novel ligament wrapping algorithms. We will then apply these models to our large in vivo database of wrist kinematics. This will give us subject specific 3-D multi-articular models of the carpus suitable for answering a myriad of both clinical and basic science questions.
Funding: National Institute of Health (NIH)
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| Carpal Kinematics During Functional Tasks |
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Work-related musculoskeletal disorders affecting the upper extremity are an important and costly national health problem. This study focuses on the skeletal mechanics of the wrist and distal forearm during functional tasks. Despite its trivial sounding name, the dart thrower’s motion (DTM), wrist motion from radial extension to ulnar flexion, oblique to the anatomical axes has been identified as one of the more important functional motions of the wrist and it critical to tasks such as hammering and throwing. The goal of this study is to evaluate changes in the carpus during these high demand tasks that are associated with workplace related musculoskeletal injury.
Funding: National Institute of Health (NIH)
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| Computer Optimized Screw Placement for Volar Percutaneous Scaphoid Fixation |
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Percutaneous fixation of acute scaphoid fractures offers rigid fixation and potentially improved healing rates without either open surgical dissection or prolonged cast immobilization. Previous studies have shown advantages to placing the screw through the bone center of mass; however it is often impossible to place a screw in this location using the volar surgical approach. The purpose of this study was to develop a repeatable method for calculating an optimal screw axis that is accessible by the volar approach. The method involved computing a shell within the scaphoid that provided a margin from the inner surface of the scaphoid of 0.25mm. For a screw to be safely placed, its central axis must be completely contained by shell.
Funding: National Institute of Health (NIH)
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| Design and Validation of a Motion-Tracking Suit to Measure Spine and Upper Extremity Kinematics |
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To better understand normal and abnormal joint motion, it is important to develop methods to measure joint motion for extended periods of time outside of a laboratory setting. This study was performed to develop and validate a self-contained motion tracking system capable of achieving this. In particular, we evaluated the accuracy of inertial measurement units (IMUs) for measuring three-dimensional kinematics using an optical motion tracking system. We found that the suit was capable of measuring functional ranges of motion of the upper extremity and spine similarly to motion-tracking systems utilized in prior studies.
Funding: Depuy Spine
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| Interfragmentary Motion in Patients with Scaphoid Nonunions |
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The scaphoid is the most commonly fractured bone in the carpus, and nonunion is common. The high failure rate of healing has been attributed to both its tenuous blood supply, the bone’s intra-synovial location, and motion between the fracture fragments. Failure to heal is associated with significant morbidity, and an inexorable progression to degenerative arthritis. The purpose of this study was to study the motion of scaphoid fracture fragments and the lunate in vivo, in patients with unilateral scaphoid fracture nonunion. In ununited scaphoids, we found the motion of the distal fragment essentially mirrored the motion of the contralateral uninjured scaphoid, but there was decreased rotation of the proximal fragment of the lunate, and a substantial amount of interfragmentary motion.
Funding: National Institute of Health (NIH)
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| Normal and Abnormal in vivo Carpal Bone Motion |
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The specific aims of this project are focused in two areas. The first three test hypotheses on normal carpal mechanics and the fourth and fifth test hypotheses on pathological carpal mechanics. The goals are to detail the complete 3-D in vivo kinematics of the carpus. This knowledge will enhance understanding of carpal function and will lead to further studies on cartilaginous and ligamentous tissues. The goals of this project are to determine the effects of two pathologies (tears of the scapholunate interosseous ligament and scaphoid fracture nonunions) on the 3-D in vivo kinematics of the carpus, with the aim of providing improved diagnostic and treatment guidelines for clinical care.
Funding:National Institute of Health (NIH) and Orthopaedic Research and Education Foundation (OREF)
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| In vitro kinematic studies generally report that the trapezoid and trapezium are tightly linked and move together on a single path relative to the scaphoid during all directions of wrist motion. In contrast to previous in vitro studies, we performed an in vivo analysis of the trapezoids and trapeziums of 10 subjects (20 wrists) using a markerless bone registration technique. We found that, on a gross level, the in vivo STT motion was consistent with that reported in vitro. However, we also found small but statistically significant relative motions between the trapezoid and trapezium, slight off-path rotations and greater amounts of trapezoid and trapezium rotations in ulnar deviation than flexion or extension. The results of this study indicate that the STT joint should be considered a mobile joint with motions more complex than previously appreciated. |
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Funding: National Institute of Health (NIH) and Orthopaedic Research and Education Foundation (OREF)
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| 3-D in vivo kinematics of the distal radio-ulnar joint in malunited distal radius fractures |
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| This study aimed to investigate the kinematics of the distal radio-ulnar joint in patients with malunited distal radius fractures. Using a novel CT-based imaging technique these patients were scanned and the kinematics of the injured and uninjured wrists were evaluated. |
Funding: NIH, Riordan-Brand Research Grant
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The goals for this project are to design and build a prototype toy line and related technologies that are actually physical rehabilitative devices. Four toy types (two slot car controllers and track, a remote car and toy controller, and a computer switch) have been completed or are nearing completion. The novel electronics specifically designed for these toys records the level of play and allows the physicians and therapist to quantify toy use.
Funding: Rhode Island Science and Technology Advisory Council
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