biplanar-videoradiography-to-study-wrist-distal-radioulnar

Biplanar Videoradiography to Study the Wrist and Distal Radioulnar Joints

Accurate measurement of skeletal kinematics in vivo is essential for understanding normal joint function, the influence of pathology, disease progression, ...

The Warren Alpert Medical School of Brown University and Rhode Island Hospital

Leg length discrepancy greater than 1cm increases odds of progressive knee osteoarthritis in the shorter limb.

Mild leg length discrepancy affects lower limbs, pelvis and trunk biomechanics of individuals with knee osteoarthritis during gait.

Osteophyte formation is a critical part of the degeneration of a joint with osteoarthritis (OA). While often qualitatively described, few studies have succeeded in quantifying osteophyte growth over time. Using computed tomography (CT) image data from a longitudinal, observational study of thumb carpometacarpal (CMC) OA, our aim was to quantify osteophyte growth volume and location over a three-year period in men and women.

Osteophyte growth in early thumb carpometacarpal osteoarthritis.

Accurately assessing the dynamic kinematics of the skeletal wrist could advance our understanding of the normal and pathological wrist. Biplane videoradiography (BVR) has allowed investigators to study dynamic activities in the knee, hip, and shoulder joint; however, currently, BVR has not been utilized for the wrist joint because of the challenges associated with imaging multiple overlapping bones. Therefore, our aim was to develop a BVR procedure and to quantify its accuracy for evaluation of wrist kinematics. BVR was performed on six cadaveric forearms for one neutral static and six dynamic tasks, including flexion-extension, radial-ulnar deviation, circumduction, pronation, supination, and hammering. Optical motion capture (OMC) served as the gold standard for assessing accuracy. We propose a feedforward tracking methodology, which uses a combined model of metacarpals (second and third) for initialization of the third metacarpal (MC3). BVR-calculated kinematic parameters were found to be consistent with the OMC-calculated parameters, and the BVR/OMC agreement had submillimeter and sub-degree biases in tracking individual bones as well as the overall joint's rotation and translation. All dynamic tasks (except pronation task) showed a limit of agreement within 1.5° for overall rotation, and within 1.3 mm for overall translations. Pronation task had a 2.1° and 1.4 mm limit of agreement for rotation and translation measurement. The poorest precision was achieved in calculating the pronation-supination angle, and radial-ulnar and volar-dorsal translational components, although they were sub-degree and submillimeter. The methodology described herein may assist those interested in examining the complexities of skeletal wrist function during dynamic tasks.

Accuracy of biplane videoradiography for quantifying dynamic wrist kinematics.

Osteophytes are associated with later stage osteoarthritis and are most commonly described using semiquantitative radiographic grading systems. A detailed understanding of osteophyte formation is, in part, limited by the ability to quantify bone pathology. Osteophytes can be quantified relative to pre-osteoarthritic bone, or to the contralateral bone if it is healthy; however, in many cases, neither are available as references. We present a method for computing three-dimensional (3D) osteophyte models using a library of healthy control bones. An existing data set containing the computed tomography scans of 90 patients with first carpometacarpal osteoarthritis (OA) and 46 healthy subjects were utilized. A healthy bone that best fit each OA subject's bone was determined using a dissimilarity-excluding Procrustes registration technique (DEP) that minimized the influence of dissimilar features (ie, osteophytes). The osteophyte model was then computed through Boolean subtraction of the reference bone model from the OA bone model. DEP reference bones conformed significantly better to the OA bones (P < .0001) than by finite difference iterative closest point registration (root mean squared distances, 0.33 ± 0.05 and 0.41 ± 0.16 mm, respectively). The effect of library size on dissimilarity measure was investigated by leave-k-out cross-validation randomly reducing k from 46 to 1. A library of n ≥ 31 resulted in less than 10% difference from the theoretical minimum value. The proposed method enables quantification of osteophytes when the disease-free bone or the healthy contralateral bone is not available for any 3D data set. Quantifying osteophyte formation and growth may aid in understating the associated mechanisms in OA.

Osteophyte volume calculation using dissimilarity-excluding Procrustes registration of archived bone models from healthy volunteers.

Methods for capturing wrist range of motion (RoM) vary in complexity, cost, and sensitivity. Measures by manual goniometer, though an inexpensive modality, provide neither dynamic nor objective motion data. Conversely, optical motion capture systems are widely used in three-dimensional scientific motion capture studies but are complex and expensive. The electrogoniometer bridges the gap between portability and objective measurement. Our study aims to evaluate the accuracy of a 2 degree of freedom electrogoniometer using optical motion capture as the reference for in vivo wrist motion. First, a mechanical system constructed from two plastic pipes and a universal joint mimicked a human wrist to assess the inherent accuracy of the electrogoniometer. Simulations of radial/ulnar deviation (R/U), flexion/extension (F/E) and circumduction were evaluated. Second, six subjects performed three RoM tasks of R/U deviation, F/E, and circumduction for evaluation of the in vivo accuracy. Bland-Altman analysis quantified the accuracy. The mechanical experiment reported greater accuracy than the in vivo study with mean difference values less than ±1°. The in vivo accuracy varied across RoM tasks, with mean differences greatest in the F/E task (7.2°). Smaller mean differences values were reported in the R/U deviation task (-0.8°) and the circumduction task (1.2°).

Accuracy of an electrogoniometer relative to optical motion tracking for quantifying wrist range of motion.

Reproduction of healthy wrist biomechanics should minimize the abnormal joint forces that could potentially result in the failure of a total wrist arthroplasty (TWA). To date, the in vivo kinematics of TWA have not been measured and it is unknown if TWA preserves healthy wrist kinematics. Therefore, the purpose of this in vivo study was to determine the center of rotation (COR) for a current TWA design and to compare its location to the healthy wrist. The wrist COR for six patients with TWA and 10 healthy subjects were calculated using biplane videoradiography as the subjects performed various range-of-motion and functional tasks that included coupled wrist motions. An open-source registration software, Autoscoper, was used for model-based tracking and kinematics analysis. It was demonstrated that the COR was located near the centers of curvatures of the carpal component for the anatomical motions of flexion-extension and radial-ulnar deviation. When compared to healthy wrists, the COR of TWAs was located more distal in both pure radial deviation (P < .0001) and pure ulnar deviation (P = .07), while there was no difference in its location in pure flexion or extension (P = .99). Across all coupled motions, the TWA's COR shifted more than two times that of the healthy wrists in the proximal-distal direction (17.1 vs 7.2 mm). We postulate that the mismatch in the COR location and behavior may be associated with increased loading of the TWA components, leading to an increase in the risk of component and/or interface failure.

Amy M Morton

Department of Orthopedics

The Warren Alpert Medical School of Brown University and Rhode Island Hospital

Biplanar Videoradiography to Study the Wrist and Distal Radioulnar Joints