A Kinematic Analysis of Wrist and Carpal Function Using Four-Dimensional Computed Tomography Technology: A Dynamic Perspective.

PURPOSE: An emerging imaging modality, four-dimensional computed tomography, can provide dynamic evaluation of carpal motion, which allows for a better understanding of how the carpals work together to achieve range of motion. The objective of this work was to examine kinematic motion of the carpus through a flexion/extension arc of motion using four-dimensional computed tomography. METHODS: A convenience sample of 20 uninjured participants underwent a four-dimensional computed tomography scanning protocol through a complete arc of flexion/extension motion. Kinematic changes in motion were quantified using helical axes motion data for each carpal. Rotation angles were compared between bones to identify differences in kinematic motion between bones. RESULTS: The bones within the proximal carpal row, the lunate, scaphoid, and triquetrum, rotate significantly to differing magnitudes at the ends of motion (40° of flexion and 40° of extension). The scaphoid rotates to the highest magnitude, followed by the triquetrum, and lastly, the lunate. The distal carpal row bones rotate to similar magnitudes throughout the entire range of motion. CONCLUSIONS: This work describes the kinematics of the carpals throughout dynamic in vivo flexion and extension. CLINICAL RELEVANCE: This study adds to an understanding of wrist mechanics and the possible clinical implications of pathological deviation from baseline kinematics.

A systematic review of the psychometric properties of pressure pain detection threshold in evaluating mechanical pain threshold in people with hand or wrist injuries.

PURPOSE: The aim of this study was to conduct a systematic review of the psychometric properties of Pressure Pain Detection Threshold (PPDT) measures in people with hand or wrist injuries. STUDY DESIGN AND METHODS: MEDLINE, Embase, and CINAHL databases were searched to identify eligible studies evaluating psychometric properties of PPDT in samples composed of at least 50% of people with hand or wrist injury. The Consensus-based Standards for the Measurement of Health Instruments' risk of bias checklist was used to critically appraise the included studies, and qualitative synthesis was performed by pooling the results of all studies that presented the same measurement property using Grading of Recommendations, Assessment, Development, and Evaluation. RESULTS: From 415 studies, 11 relevant studies were identified. Of the 11 studies, four hand or wrist injuries were represented; carpal tunnel syndrome, distal radius fractures, osteoarthritis, and complex regional pain syndrome. Intra-rater reliability was considered sufficient (intraclass correlation coefficient 0.64-0.94), with small reported standard error of the mean values (5.3-39.2 kPa). Results of validity and responsiveness could not be synthesized due to heterogeneity. Risk of bias for reliability and measurement error was assessed as very good or adequate, whereas validity and responsiveness were doubtful or inadequate. Overall quality of evidence was low or very low for all measurement properties. CONCLUSIONS: Inconsistent results and low quality evidence provide little confidence in the overall measurement properties of PPDT in a hand or wrist injury population. No criterion standard for pain further highlights complexities around pain measurement such that the results obtained from PPDT measures in clinical practice cannot be compared to a gold standard measure.

The Utility of Quantitative Computed Tomography to Detect Differences in Subchondral Bone Mineral Density Between Healthy People and People With Pain Following Wrist Trauma.

The mechanisms underlying chronic pain development following musculoskeletal trauma are complex and multifactorial. In their search, some researchers are turning to the subchondral bone as a potential contributor to pain due to its vascularity, using a depth-specific imaging technique. However, this technique has been mainly used in the knee. We propose the use of a quantitative computed tomography (QCT) depth-specific analysis to measure subchondral bone following wrist trauma. Ten participants (n = 5 post-trauma; n = 5 healthy) underwent bilateral computed tomography scans of their wrist accompanied by a calibration phantom with known densities. Average subchondral volumetric bone mineral density (vBMD) was studied at three depths from the subchondral surface (0-2.5, 2.5-5, 5-7.5 mm) according to radial articular surface contact in both wrists of each participant. Percentage differences and Cohen's d effect sizes were calculated to analyze bilateral vBMD and vBMD differences between groups. This image-based tool demonstrated subject-specific, depth-specific, and joint-specific measures of vBMD within the wrist. This methodology highlighted the differences between depth-specific vBMD in healthy people and people who have experienced wrist trauma. Overall, the healthy cohort demonstrated higher vBMD across all three depths and both articular surfaces. This imaging technique further distinguished between subchondral cortical and trabecular bones, wherein clinical implications can be drawn from these distinctions in future work. Our study therefore supports the utility of a QCT imaging technique in detecting differences in depth-specific vBMD in the wrist.

Comparison of finger kinematics between patients with hand osteoarthritis and healthy participants with and without joint protection programs.

STUDY DESIGN: This is a cross-sectional, clinical observational study. BACKGROUND: Finger range of motion (ROM) and functional performance are critical in many daily activities. Hand osteoarthritis (H-OA) is a prevalent disease that impairs both variables. Little quantitative research has been performed on finger kinematics during activities of daily living (ADLs) across health status and method of performance (with or without joint protection programs). PURPOSE: The purpose of this research is to examine the effects of H-OA and method of performance on ROM in the thumb, index, and middle digits (flexion/extension and abduction/adduction) during ADLs. METHODS: This study was conducted using 10 healthy participants (mean age: 28 years) and nine participants with H-OA (mean age: 72 years). All participants performed baseline ROM movements followed by 9 activities of daily living. These activities involved prehension type grasps and were performed with and without the recommended joint protection procedures specific to each task. Thumb IP and MCP, index distal interphalengeal (DIP) and proximal interphalengeal (PIP), and middle DIP and PIP joints were continuously recorded using an electromagnetic tracking system for ROM analysis. RESULTS: Participants with H-OA had a statistically significant decrease in ROM when comparing values measured in the healthy cohort during active ROM (25° decrease) and ADL ROM (25° decrease) in the flex/ext direction. Similarly, following joint protection instruction, a statistically significant decrease in ROM was found during tasks in the flex/ext direction (healthy participant decrease in ROM: 17°, H-OA decrease in ROM:10°) CONCLUSIONS: This study demonstrated that people with hand arthritis move through a smaller arc of motion when performing some functional tasks as compared with the controls, and that with instruction on joint protection techniques, participants made significant changes in the amount of movement used to perform tasks, which supports a proof of principle of joint protection.

Evaluation of Four-Dimensional Computed Tomography as a Technique for Quantifying Carpal Motion.

Delayed diagnosis of dynamic carpal instability often occurs because early changes in bone alignment and movement are difficult to detect and manifest mainly during a dynamic/functional task. Current diagnostic tools are only able to examine the carpal bones under static or sequential-static conditions. Four-dimensional (three dimensions + time) computed tomography (4DCT) enables quantification of carpal mechanics through 3D volume sequences of the wrist in motion. A comprehensive understanding of carpal mechanics is needed to define normal function and structure and provide targets for treatment of carpal injuries. In this study, measurements of scaphoid translation and joint congruency were taken by creating models from the CT scans of the carpals in extreme frames of motion, registering those models to the neutral position, transforming the models into a local coordinate system, and using software to calculate the joint surface areas (JSA). Results indicated that the centroid of the scaphoid translated 6.4 ± 1.3 mm and extended from extreme radial to extreme ulnar deviation. Results are consistent with the literature. An additional study was performed to measure the responsiveness of the 4DCT technique presented. Bone models from each frame of motion for radio ulnar deviation (RUD) and flexion extension (FE) were created and distinct differences between their JSA were measured qualitatively and quantitatively. The results show that there was statistically significantly different JSA within carpal joints between RUD and FE. These studies provide the first step in developing the methodology when using 4DCT scanning to measure subtle abnormalities in the wrist.

The Effect of Distal Radius Fractures on 3-Dimensional Joint Congruency.

PURPOSE: Whereas the goal of distal radius fracture treatment is anatomical restoration, controversy exists as to whether it is the severity of the disruption of joint alignment at the time of fracture or residual malalignment after healing that determines outcome. The objective of this study was to compare joint contact mechanics bilaterally a minimum of 3 years following a distal radius fracture. Our hypothesis was that 3-dimensional joint space would be reduced in individuals following wrist fracture and that these changes in joint load lead to the development of degenerative arthritis. To test the hypothesis, an interbone spacing algorithm was used to determine whether 3-dimensional joint space and contact mechanics were altered in the distal radioulnar (DRUJ) and radiocarpal joints following a wrist fracture. METHODS: In 16 subjects with previous unilateral wrist fractures, 3-dimensional interbone distance (joint space), a measure of joint congruency and 3-dimensional alignment, was quantified from reconstructed computed tomography bone models of the distal radius, ulna, scaphoid, and lunate. RESULTS: At an average of 8 years following fracture, joint interbone spacing area was reduced in the radiolunate joint of the injured wrist in comparison with the uninjured wrist. The joint interbone spacing area was decreased in the DRUJ and radioscaphoid joint of the injured wrist compared with the uninjured wrist but this difference was not statistically significant. CONCLUSIONS: This study demonstrates the use of a noninvasive tool that can be used to examine joint loading and suggests that further investigation into the association between altered joint loading and the development of posttraumatic arthritis is needed, especially in the radiocarpal joints. CLINICAL RELEVANCE: This paper provides a noninvasive image-based framework that can be used to examine joint contact area over time and provides preliminary data examining the effect of a distal radius fracture on the joint congruency of the DRUJ and radiocarpal joints.

The Effect of Malunited Scaphoid Fractures on Joint Congruency.

PURPOSE: Although the consequences of scaphoid nonunion have been well-established, the implications of malunions are not well-known. To date, malunions have mainly been studied with 2-dimensional imaging. The objective of this study was to employ 3-dimensional computed tomography (CT) imaging and inter-bone distance mapping to determine the implications of a scaphoid malunion on 3-dimensional joint surface area (JSA) (a measure of joint contact area) at an average of 7 ± 2 years (range, 4-12 years) after fracture. METHODS: In 14 subjects with previous unilateral, malunited scaphoid fractures, we measured the 3-dimensional JSA using reconstructed CT bone models of the carpus. The JSA was compared within each individual, comparing images of the wrist collected at the time of fracture (baseline) and 7 years later (follow-up CT scans). RESULTS: There was a significant increase in the measured JSA (reduced joint space) at the scaphotrapezial (23% increase) and scaphocapitate (13% increase) joints when the baseline and follow-up scans of the wrist were compared. An increased JSA indicates that the 2 opposing surfaces are closer in contact and have a reduced joint spacing reflective of degenerative changes. However, participants in this study showed no radiographic signs of degenerative changes in the wrists at midterm follow-up. CONCLUSIONS: An increase in JSA was found in patients with a malunited scaphoid in the scaphotrapezial and scaphocapitate joints of the wrist an average of 7 years after injury, but these joint changes were not evident in measured radiographic signs of arthritis. CLINICAL RELEVANCE: As early as 4 years after injury, the 3-dimensional JSA is significantly increased at the scaphocapitate and scaphotrapezial joints. Future work is needed to determine the implication of this increased in 3-dimensional JSA on the underlying subchondral bone, and to observe these patients for longer to determine whether degenerative changes develop.

Evaluation of the content validity index of the Australian/Canadian osteoarthritis hand index, the patient-rated wrist/hand evaluation and the thumb disability exam in people with hand arthritis.

BACKGROUND: The Australian/Canadian Osteoarthritis Hand Index (AUSCAN), the Patient-Rated Wrist/Hand Evaluation (PRWHE) and the Thumb Disability Exam (TDX) are patient-reported outcome measures (PROM) designed to assess pain and hand function in patients with hand arthritis, hand pain and disability, or thumb pathology respectively. This study evaluated the content validity of AUSCAN, PRWHE and TDX in people with hand arthritis. METHODS: This study enrolled participants with hand arthritis to rate the items of all 3 PROM in terms of relevance and clarity. The Content Validity Index (CVI) was computed for each item in each scale (I-CVI) as well as for the overall scale (S-CVI). Kappa was used to determine the inter-rater agreement among the raters. RESULTS: Overall, 64 individuals with hand arthritis (27% with OA, 67% with rheumatoid arthritis and 6% with psoriatic arthritis) participated in the study. The I-CVI for all items and all scales were very high (I-CVI > 0.76) and the modified Kappa agreement among the raters demonstrated excellent agreement (k > 0.76). The S-CVI for all PROMs was very high for relevance (AUSCAN = 0.92, 95% CI 0.90 to 0.94; PRWHE = 0.85, 95% CI 0.82 to 0.88 and TDX = 0.87, 95% CI 0.85 to 0.89) and for clarity (AUSCAN = 0.99, 95% CI 0.98 to 1.00; PRWHE = 0.95, 95% CI 0.93 to 0.97 and TDX = 0.91, 95% CI 0.89 to 0.94), respectively. CONCLUSIONS: This study demonstrated very high content validity indices for the AUSCAN, PRWHE and TDX; with strong consensus across raters. This augments prior studies demonstrating appropriate statistical measurement properties, to provide confidence that all three measures assess important patient concepts of pain and disability.

Evaluation of individual finger forces during activities of daily living in healthy individuals and those with hand arthritis.

INTRODUCTION: Measuring finger forces during activities of daily living and how these forces change for individuals with pathologies such as arthritis is valuable to our understanding of hand function. PURPOSE OF THE STUDY: The purpose of this study was to determine the forces of individual fingers during the performance of daily activities in healthy participants and determine the envelope of these applied forces. METHODS: This is a cross-sectional study investigating twenty-five healthy participants (12 female: 22-65 years old and 13 male: 20-53 years old) and participants with osteoarthritis (12 female: 52-79 years old and 9 male: 64-79 years old) examined at one time point. The force sensors were calibrated for each individual using a load cell to provide force output in Newtons. Each participant performed 19 activities of daily living two times. Force was plotted over time for each task, and the maximum force in each finger during that task was evaluated. RESULTS: The range of applied forces was 1.4 ± 0.6 N to 34.8 ± 1.6 N for healthy participants and 2.3 ± 1.0 N to 30.7 ± 3.7 N for those with osteoarthritis. DISCUSSION: Sensors allowed for real-time monitoring of finger forces during tasks of daily life. This provides the opportunity to isolate hand grips based on finger recruitment and provide information about the magnitude of forces during the activity. CONCLUSION: Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions.

An Anthropometric Assessment of the Proximal Hamate Autograft for Scaphoid Proximal Pole Reconstruction.

PURPOSE: Fragmentation of the scaphoid proximal pole secondary to avascular necrosis presents a difficult reconstructive problem. This anthropometric study assesses the utility of the ipsilateral proximal hamate for complete osteochondral scaphoid proximal pole reconstruction. METHODS: Twenty-nine cadaveric specimens underwent computed tomography scanning and 3-dimensional reconstruction of the carpus and distal radius. Scaphoid height was measured and a third of its height was used to simulate resection of the proximal scaphoid pole and extent of hamate autograft required. The proximal scaphoid and hamate were divided into 6 sections, and compared using an iterative point-to-point distance algorithm. Average distance between the scaphoid and the hamate surfaces was determined. An interbone algorithm was used to assess radioscaphoid joint congruency and articular contact surface of the native scaphoid compared with the scaphoid reconstructed with hamate autograft. RESULTS: The mean height of scaphoid proximal pole excision and proximal hamate autograft height was 9.3 mm. Comparing the morphology of the native scaphoid and hamate autografts, the absolute distances were the largest in the volar radioscaphoid, dorsal radioscaphoid, and dorsal scaphocapitate segments. Without osteotomy, the hamate autograft may cause impaction in the dorsal-radial aspect of the distal radius. The hamate autograft also shifted the articular contact point of the radioscaphoid joint toward the dorsal-radial position. Nine hamate autografts were classified as poor-fitting. Poor-fitting specimens had a greater radial styloid to distal radioulnar joint distance. These specimens also had wider hamates and scaphoids in the radial-ulnar dimension and wider scaphoids in the volar-dorsal dimension. Lunate type did not correspond to anthropometric fit. CONCLUSIONS: The proximal hamate osteochondral graft was poor fitting in 31% of cases (9 of 29 specimens). Wrists with radial-ulnar hamate width less than 10 mm, radial-ulnar scaphoid width less than 10 mm, and volar-dorsal scaphoid width less than 16 mm demonstrate better anthropometric fit. CLINICAL RELEVANCE: This study provides an anthropometric assessment of the recently described proximal hamate autograft, a new bone graft option for proximal scaphoid pole reconstruction.

Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures.

PURPOSE: Anthropometric assessment of bony structures in the body is important for preoperative computer-aided surgery, implant design, finite element modeling, and biomechanical studies investigating joint structure and function. The use of the contralateral limb in surgery and clinical practice relies on the assumption that the right and left limbs of an individual are symmetric. Therefore, the purpose of this study was to quantify the bilateral symmetry of the bony structures of the distal radius using 3-dimensional (3D) computed tomography. METHODS: We collected computed tomography images of 37 paired, fresh-frozen, healthy cadaveric male upper limbs (aged 75.4 ± 8.3 years). Three-dimensional reconstructed models were created using semiautomatic segmentation. Using the 3D models, we measured 3D radial inclination, 3D volar tilt, 3D radial height, medial volar cortical angle, middle volar cortical angle, and lateral volar cortical angle and compared them between sides. RESULTS: There were no statistically significant differences measured between right and left distal radius in 37 paired wrists. Mean radial height was 12.81 mm (SD, 1.74 mm) on the left and 12.88 mm (SD, 1.72 mm) on the right. Mean volar tilt was 10.74° (SD, 3.74°) and 10.77° (SD, 3.19°) and radial inclination was 24.05° (SD, 2.63°) and 24.18° (SD, 3.41°) on the left and right, respectively. Mean volar cortical angle across the radius was 140.9° (SD, 7.9°) on the left and 140.1° (SD, 7.9°) on the right. CONCLUSIONS: Direct bilateral comparison of the distal radius and wrist joints is useful to predict normal anatomy of the injured radius, because bilateral similarities exist. CLINICAL RELEVANCE: This article provides a comprehensive list of measurements of the distal radius compared bilaterally using a 3D model. From this study, we found that the contralateral radius can be used as a benchmark with which to compare fracture reduction and to manage malunions during the preoperative planning of corrective osteotomies. It can also be used to define normal anatomy.

Computed Tomography Analysis of the Radial Notch of the Ulna.

PURPOSE: The anatomy of the radial head and capitellum has been extensively studied; however, the anatomy of the radial notch of the ulna (RNU) has received little attention. This imaging-based anatomic study characterizes the morphology of the RNU. METHODS: Ninety-eight cadaveric arms (57 male, 72 ± 14 y) were imaged with computed tomography, and 3-dimensional reconstructions of the proximal ulna were constructed. The anteroposterior and proximal-distal dimensions of the RNU as well as the radius of curvature at standardized levels were measured in 2-mm increments. The orientation of the RNU was also determined. RESULTS: The proximal-distal and anteroposterior dimensions of the RNU were 12 ± 2 mm (range, 7-16 mm) and 18 ± 3 mm (range, 12-24 mm), respectively. The average radius of curvature of the RNU was 15 ± 0 mm (range, 15-16 mm). The radius of curvature did not change significantly when comparing the proximal and distal aspect of the RNU. The RNU was rotated 33° ± 2° (range, 31° to 38°) externally relative to the transverse plane of the ulna. The average depth of the RNU at its deepest point was 2.2 ± 0.4 mm (range, 1.5-2.7 mm). The depth decreased from proximal to distal, being most shallow distally. The depth changed by an increase of the radius of curvature, as well as by rotation in the frontal plane. CONCLUSIONS: The RNU anatomy was variable, generally extending laterally from proximal to distal. This suggests that a radial head implant should taper from proximal to distal to optimize contact at the RNU. CLINICAL RELEVANCE: The present study investigates the detailed anatomy of the radial notch of the ulna using computed tomography scans. The data might help improve the design of prosthetic components.

The shape match of the olecranon tip for reconstruction of the coronoid process: influence of side and osteotomy angle.

BACKGROUND: The integrity of the coronoid process is critical to maintaining elbow stability. Unreconstructible fractures and chronic coronoid deficiency are challenging clinical problems with no clear solution. The purposes of this study were to investigate the shape match of the ipsilateral and contralateral olecranon tips as graft options and to determine the influence of the osteotomy angle on fitment. METHODS: Nineteen paired cadaveric elbow joints were investigated by 3-dimensional digital analysis of computed tomography DICOM (Digital Imaging and Communications in Medicine) data. After construction of an ulnar coordinate system, the ipsilateral and contralateral olecranon tips were digitally harvested at 10°, 20°, 30°, 40°, 50°, and 60° osteotomy angles. In an overlay analysis, we compared the shape match of the ipsilateral and contralateral grafts and the different angles. RESULTS: The ipsilateral grafts showed an average mismatch of 1.8 mm (standard deviation, 1.38 mm), whereas the contralateral grafts had a significantly lower (P < .001) mean mismatch of 1.3 mm (standard deviation, 0.95 mm). The 50° osteotomy plane showed the best shape match in comparison with the native coronoid-in both the ipsilateral and contralateral grafts. Evaluation of the intraclass correlation coefficient was calculated at r = 0.944, showing high repeatability of the measurements. CONCLUSIONS: The contralateral olecranon tip graft showed significantly better shape matching to the native coronoid than the ipsilateral olecranon graft. Specifically, the contralateral graft more closely matched the biomechanically critical anteromedial coronoid facet. Finally, both the contralateral and ipsilateral olecranon grafts had better shape matching with the native coronoid when osteotomy was performed at higher angles, specifically 50°.

Establishing the psychometric properties of 2 self-reported outcome measures of elbow pain and function: A systematic review.

STUDY DESIGN: Systematic review. INTRODUCTION: The Patient-Rated Elbow Evaluation (PREE) and the self-report section of the American Shoulder and Elbow Surgeons-elbow form (pASES-e) are 2 patient-reported outcome measures (PROMs) commonly used to assess pain and disability arising from elbow disorders. PURPOSE OF THE STUDY: To systematically review and summarize the quality and content of the evidence that is available on the psychometric properties of the PREE and pASES-e. METHODS: We systematically searched the online databases PubMed, EMBASE, ProQuest, Scopus, Cumulative Index to Nursing and Allied Health Literature, UptoDate, ProQuest Dissertations & Theses, and Google Scholar. Ninety-one articles were retrieved, and after screening, 9 were included in the final analysis. Data extraction and quality appraisal was performed by 2 independent raters. Descriptive synthesis of the reviewed studies was completed. RESULTS: Seven of the 9 studies had a quality score of 75% or higher. Agreement between the raters was good (kappa, 0.81). Both the PROMs did not demonstrate any floor and ceiling effects except for the satisfaction subscale of the pASES-e. Factor analysis revealed multidimensionality in the function subscale for both the PROMs. Construct validity was good with correlations above 0.70. Both were highly reliable with interclass correlation coefficient of >0.90. They were also highly responsive with an effect size and standardized response mean above 1. The minimal clinical important difference was not estimated for either measures. DISCUSSION: This study concluded that strong clinical measurement properties exist for both the PREE and the pASES-e. We identified gaps in the current evidence for both the ASES-e and the PREE. Future studies need to calculate clinically important estimates like MCID, SEM, and others; and provide clear and specific conclusions. CONCLUSION: The PREE and pASES-e have been established to be valid, reliable, and sensitive to change in both clinical and research settings based on high-quality evidence.

The effectiveness of joint-protection programs on pain, hand function, and grip strength levels in patients with hand arthritis: A systematic review and meta-analysis.

STUDY DESIGN: Systematic review with meta-analysis. INTRODUCTION: Joint protection (JP) has been developed as a self-management intervention to assist people with hand arthritis to improve occupational performance and minimize joint deterioration over time. PURPOSE OF THE STUDY: We examined the effectiveness between JP and usual care/control on pain, hand function, and grip strength levels for people with hand osteoarthritis and rheumatoid arthritis. METHODS: A search was performed in 5 databases from January 1990 to February 2017. Two independent assessors applied Cochrane's risk of bias tool, and a Grading of Recommendations Assessement, Development and Evaluation (GRADE) approach was adopted. RESULTS: For pain levels at short term, we found similar effects between JP and control standardized mean difference (SMD; -0.00, 95% confidence interval [CI]: -0.42 to 0.42, I2 = 49%), and at midterm and long-term follow-up, JP was favored over usual care SMD (-0.32, 95% CI: -0.53 to -0.11, I2 = 0) and SMD (-0.27, 95% CI: -0.41 to -0.12, I2 = 9%), respectively. For function levels at midterm and long-term follow-up, JP was favored over usual care SMD (-0.49, 95% CI: -0.75 to -0.22, I2 = 34%) and SMD (-0.31, 95% CI: -0.50 to -0.11, I2 = 56%), respectively. For grip strength levels, at long term, JP was inferior over usual care mean difference (0.93, 95% CI: -0.74 to 2.61, I2 = 0%). CONCLUSIONS: Evidence of very low to low quality indicates that the effects of JP programs compared with usual care/control on pain and hand function are too small to be clinically important at short-, intermediate-, and long-term follow-ups for people with hand arthritis.

Arthrokinematics of the Distal Radioulnar Joint Measured Using Intercartilage Distance in an In Vitro Model.

PURPOSE: Current techniques used to measure joint contact rely on invasive procedures and are limited to statically loaded positions. We sought to examine native distal radioulnar joint (DRUJ) contact mechanics using nondestructive imaging methods during simulated active and passive forearm rotation. METHODS: Testing was performed using 8 fresh-frozen cadaveric specimens that were surgically prepared by isolating muscles involved in forearm rotation. A wrist simulator allowed for the evaluation of differences between active and passive forearm rotation. Three-dimensional cartilage surface reconstructions were created using volumetric data acquired from computed tomography. Using optically tracked motion data, the relative position of the cartilage models was rendered and used to measure DRUJ cartilage contact mechanics. The effects of forearm movement method and rotation angle on centroid coordinate data and DRUJ contact area were examined. RESULTS: The DRUJ contact area was maximal at 10° supination. There was more contact area in supination than pronation for both active and passive forearm rotation. The contact centroid moved volarly with supination, with magnitudes of 10.5 ± 2.6 mm volar for simulated active motion and 8.5 ± 2.6 mm volar for passive motion. Along the proximal-distal axis, the contact centroid moved 5.7 ± 2.4 mm proximal during simulated active motion. These findings were statistically significant. The contact centroid moved 0.2 ± 3.1 mm distal during passive motion (not significant). CONCLUSIONS: It is possible to examine cartilage contact mechanics of the DRUJ nondestructively while undergoing simulated, continuous active and passive forearm rotation. The contact centroid moved volarly and proximally with supination. There were higher contact area values in supination compared with pronation, with a peak value at 10° supination. CLINICAL RELEVANCE: This study documented normal DRUJ arthrokinematics using a nondestructive in vitro approach. It further reinforced the established biomechanical and clinical literature on contact patterns at the native DRUJ during forearm rotation.

The Effect of Dorsally Angulated Distal Radius Deformities on Carpal Kinematics: An In Vitro Biomechanical Study.

PURPOSE: The purpose was to quantify the effect of distal radius dorsal angulation (DA) on carpal kinematics and the relative roles of the radiocarpal and midcarpal joints during wrist motion. METHODS: Six cadaveric specimens (69 ± 17 y) were mounted at 90° elbow flexion in a custom wrist motion simulator. The wrist was guided through planar passive flexion and extension motion trials (∼ 5°/s). A custom modular distal radius implant was used to simulate native alignment and 3 distal radius DA deformities (10°, 20°, 30°). An optical tracking system captured carpal bone motion, from which radiocarpal and midcarpal joint motion was determined. RESULTS: The radiocarpal joint made a greater contribution to wrist motion than the midcarpal joint in flexion, and the midcarpal joint made a greater contribution to motion than the radiocarpal joint in wrist extension. Increasing DA caused the radiocarpal joint contribution to increase throughout the motion arc, with the effect being more pronounced in wrist flexion. Conversely, as DA increased, the midcarpal joint contributed less rotation to the total wrist motion and its overall motion arc decreased; the magnitude of effect was greater in wrist extension. Dorsal angulation resulted in increased lunate flexion with respect to the distal radius. CONCLUSIONS: Our findings agree with current literature that suggests that, in an uninjured wrist, the radiocarpal joint predominates flexion, and the midcarpal joint predominates extension. In addition, the radiocarpal joint has an amplified contribution in wrist flexion with greater DA malunion. CLINICAL RELEVANCE: The altered contributions of the radiocarpal and midcarpal joints may contribute to pain, stiffness, and the development of arthritis, which is commonly seen at the radiocarpal joint after malunion of the distal radius.

Recovery, age, and gender effects on hand dexterity after a distal radius fracture. A 1-year prospective cohort study.

STUDY DESIGN: A prospective cohort study. INTRODUCTION: Physical factors that predict hand dexterity and the recovery of hand dexterity after a distal radius fracture (DRF) have not yet been examined. PURPOSE OF THE STUDY: The first objective was to evaluate the recovery of hand dexterity comparing the injured and uninjured hands during the year after a DRF. The second objective was to determine the effect of age and sex on hand dexterity of the injured hand. METHODS: Hand dexterity was examined bilaterally for the manipulation of 3 different sized objects (small, medium, and large) using the NK hand dexterity test. The measurements took place at 3, 6, and 12 months after DRF. Generalized linear modeling was performed, with age and sex as covariates, to assess changes over time, and between sides. RESULTS: Overall, 242 patients with DRF (45 males and 197 females) with a mean age of 60.2 years with SD of 11.26, participated in the study. Statistical differences in hand dexterity were found between the injured and uninjured hands across all time intervals (P < .001). The effect size for the deficit between the injured and uninjured hands decreased across the time intervals and ranged from 0.19 to 0.38 for large objects, from 0.17 to 0.25 for medium objects, and from 0.11 to 0.32 for small objects. For each 1-year increase in age, hand dexterity scores were 0.3-0.4 seconds slower. Sex had much less effect, with annual increases of 0.1 seconds in hand dexterity scores. CONCLUSIONS: Scores on the NK dexterity test improved between 3 and 6 months and then worsened between 6 and 12 months; at no point did dexterity equal the uninjured side. Greater attention to measuring and treating dexterity may be needed to provide a complete recovery after DRF. Scores will be affected by age and sex. LEVEL OF EVIDENCE: Prognosis, 2a.

Design of Anatomical Population-Based and Patient-Specific Radial Head Implants.

PURPOSE: The objective of this study was to characterize the morphology of the radial head and design population-based anatomical and patient-specific radial head implants. METHODS: Computed tomography (CT) images of 50 normal cadaveric upper extremities (34 male, 16 female) were obtained using a 64-slice CT scanner. Surface models were ellipse-fitted and characterized. Using an intersurface distance mapping approach, the surface geometry of the population-based anatomical design (PB-An), 3 distinct patient-specific designs, and an existing axisymmetrical implant (Com-Axi) were compared with the native radial head and the overall surface mismatch was measured. RESULTS: Morphological analysis indicated that the diameters of the outer and rim ellipses were correlated. The mean mismatch for the existing commercially available axisymmetrical implants was 0.5 ± 0.1 mm.The PB-An implants showed significantly reduced surface mismatch (0.4 ± 0.2 mm). The PS-An implant using 82 parameters in its design (0.1 ± 0.0 mm), had the lowest mean surface mismatch of any of the implants investigated. CONCLUSIONS: The mean surface mismatch of radial head implants may be reduced using reverse engineering techniques to determine the required parameters for both population-based and patient-specific implant designs. Whether there is a significant clinical advantage of a more anatomically shaped radial head implant requires additional study. More anatomical implant shapes rely on a surgical technique to accurately position these implants during surgery. It is unclear if this can be achieved clinically using conventional techniques or whether computer-assisted surgery will be required to realize the potential advantages of a more anatomical implant. CLINICAL RELEVANCE: This study characterized the morphology of the radial head with implications for population-based anatomical implants and patient-specific implants. The overall design of each implant was quantitatively compared with the native radial head. This study has implications for the design of patient-specific/anatomical implants and compares their use with commercially available generic implants.

Effect of Radial Head Implant Shape on Radiocapitellar Joint Congruency.

PURPOSE: Radial head arthroplasty is indicated in displaced fractures in which comminution precludes successful internal fixation. Many types of radial head implants have been developed varying in material, methods of fixation, and degrees of modularity and geometry. The purpose of this study was to investigate the effect of radial head implant shape on radiocapitellar joint congruency. METHODS: Joint congruency was quantified in 7 cadaveric specimens employing a registration and inter-surface distance algorithm and 3-dimensional models obtained using computed tomography. Forearm rotation was simulated after computer-guided implantation of an axisymmetric radial head, a population-based quasi-anatomic radial head implant, and a reverse-engineered anatomic radial head implant. Inter-surface distances were measured to investigate the relative position of the radial head implant and displayed on 3-dimensional color-contour maps. Surface area was measured for inter-surface distances (1.5 mm) and compared for each radial head geometry. RESULTS: There were no statistical differences in the contact surface area between radial head implants during active or passive forearm rotation. The joint was more congruent (larger contact surface area) during active forearm rotation compared with passive forearm rotation. CONCLUSIONS: This study investigated the effect of implant geometry on the radiocapitellar joint contact mechanics by examining a commercially available radial head system (axisymmetric), a quasi-anatomic design, and an anatomic reverse-engineered radial head implant. We found no statistical differences in radiocapitellar joint contact mechanics as measured by 3-dimensional joint congruency in cadaveric specimens undergoing continuous simulated forearm rotation. CLINICAL RELEVANCE: The importance of choosing an implant that matches the general size of the native radial head is recognized, but the degree to which it is necessary to create an implant that replicates the native anatomy to restore elbow stability and prevent cartilage degenerative changes remains unclear. This study concluded that the geometry of the implant did not have a statistically significant effect on joint contact mechanics; therefore, future work is needed to examine additional factors related to implant design, such as material choice and implant positioning to investigate their influence on joint contact mechanics.