Radial-ulnar Deviation Research Articles

Control limitations in the null-space of the wrist muscle system

The redundancy present within the musculoskeletal system may offer a non-invasive source of signals for movement augmentation, where the set of muscle activations that do not produce force/torque (muscle-to-force null-space) could be controlled simultaneously to the natural limbs. Here, we investigated the viability of extracting movement augmentation control signals from the muscles of the wrist complex. Our study assessed (i) if controlled variation of the muscle activation patterns in the wrist joint’s null-space is possible; and (ii) whether force and null-space cursor targets could be reached concurrently. During the null-space target reaching condition, participants used muscle-to-force null-space muscle activation to move their cursor towards a displayed target while minimising the exerted force as visualised through the cursor’s size. Initial targets were positioned to require natural co-contraction in the null-space and if participants showed a consistent ability to reach for their current target, they would rotate 5∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ$$\\end{document} incrementally to generate muscle activation patterns further away from their natural co-contraction. In contrast, during the concurrent target reaching condition participants were required to match a target position and size, where their cursor position was instead controlled by their exerted flexion–extension and radial-ulnar deviation, while its size was changed by their natural co-contraction magnitude. The results collected from 10 participants suggest that while there was variation in each participant’s co-contraction behaviour, most did not possess the ability to control this variation for muscle-to-force null-space virtual reaching. In contrast, participants did show a direction and target size dependent ability to vary isometric force and co-contraction activity concurrently. Our results indicate the limitations of using the muscle-to-force null-space activity of joints with a low level of redundancy as a possible command signal for movement augmentation.

Comparative study of short-term effectiveness of three surgical methods for ulnar styloid base fracture complicated with triangular fibrocartilage complex injury

To compare the short-term effectiveness of arthroscopic suture of triangular fibrocartilage complex (TFCC), arthroscopic suture of TFCC combined with open reduction and internal fixation, and simple open reduction and internal fixation in the treatment of distal radius fractures combined with ulnar styloid base fractures and TFCC injury. A clinical data of 97 patients with distal radius fractures combined with ulnar styloid base fracture and TFCC injury, who were admitted between September 2019 and September 2022 and met the selective criteria, was retrospectively analyzed. After reduction and internal fixation of distal radius fractures, 37 cases underwent arthroscopic suture of TFCC (TFCC group), 31 cases underwent arthroscopic suture of TFCC combined with open reduction and internal fixation of ulnar styloid base fractures (combination group), and 29 cases underwent simple open reduction and internal fixation of ulnar styloid base fractures (internal fixation group). There was no significant difference in baseline data between groups ( P>0.05), such as gender, age, injury side, time from injury to operation, and preoperative radius height, palm inclination, ulnar deviation, grip strength, wrist range of motion (ROM) in rotation, ulnar-radial deviation, and flexion-extension. The differences (change value) in radius height, metacarpal inclination angle, ulnar deviation angle, grip strength, and wrist ROM in rotation, ulnar-radial deviation, and flexion-extension between preoperative and 12 months after operation in 3 groups were compared. The effectiveness was evaluated according to the modified Gartland-Werley score at 12 months after operation. All incisions healed by first intention. All patients were followed up 12-18 months (mean, 14 months). X-ray films showed that there were 4 patients with non-union of ulnar styloid base fracture in TFCC group, and the remaining patients had fracture healing at 3 months after operation. The radius height, palm inclination, and ulnar deviation of 3 groups at 12 months after operation were significantly better than those before operation ( P<0.05); however, the differences in the change values of the above indexes between groups was not significant ( P>0.05). At 12 months after operation, the change values of wrist ROM in rotation, ulnar-radial deviation, and flexion-extension in the TFCC group and the combination group were significantly greater than those in the internal fixation group ( P<0.05), and there was no significant difference between the TFCC group and the combination group ( P>0.05). The change values of grip strength was significantly greater in the combination group than in the internal fixation group ( P<0.05); there was no significant difference between the other groups ( P>0.05). The excellent and good rates according to the modified Gartland-Werley score were 91.89% (34/37), 93.54% (29/31), and 72.41% (21/29) in the TFCC group, the combination group, and the internal fixation group, respectively. The excellent and good rates of the TFCC group and the combination group were significantly higher than that of the internal fixation group ( P<0.05); there was no significant difference between the TFCC group and the combination group ( P>0.05). For ulnar styloid base fractures with TFCC injury, compared with simple open reduction and internal fixation, arthroscopic suture of TFCC or suture TFCC combined with internal fixation treatment are both beneficial for wrist function recovery, and their short-term effectiveness are similar. Therefore, arthroscopic suture of TFCC may be a better choice.

The Relationship between Structure of the Wrist and Function in a Japanese and Caucasian Population.

Background: Factors such as age and joint structure affect normal wrist motion. The midcarpal joint participates in flexion/extension, radial-ulnar/deviation (RUD), and since lunate/wrist type-2 is likely more stable than a lunate/wrist type-1, we suggest that midcarpal joint structure will affect wrist motion. Our purpose was to compare wrist motion in Caucasian and Japanese populations and to associate motion with midcarpal joint morphology. We hypothesised that radiographic structure would correlate with wrist motion. Methods: A total of 164 patients with normal wrist radiographs were included. Clinical measurements included wrist extension, flexion and RUD. Radiographic measurements included the radiocarpal joint: ulnar variance, radial height, radial inclination, volar inclination and carpal joint measurements: lunate type, capitate circumference and each of its joints contact measured and calculated as a proportion of capitate circumference. Results: The groups differed in wrist motion and in multiple radiographic measurements. When the two populations were analysed together, there were no significant associations between midcarpal joint type and wrist motion. The radiocarpal joint: ulnar variance was correlated with extension and radial deviation. Radial height was directly related to flexion, and both radial height and radial inclination were directly correlated with ulnar deviation. The intracarpal measurements: The main measurement affecting motion was the contact between the capitate and the scaphoid (as a proportion of capitate circumference) with lesser correlations of the contact of the capitate with the trapezoid and hamate. The most significant measurement associated with a lunate type-2 was scaphoid contact with the capitate p = 0.01. Logistic regression demonstrated that the measurements most associated with wrist motion were scaphoid contact with the capitate/capitate circumference and hamate contact with the capitate/capitate. Conclusions: This study supports discrepancies in wrist motion amongst different racial cohorts, and a relationship between bone/joint structure in the wrist and wrist motion. This can help treat wrist pathology. Level of Evidence: Level III (Diagnostic).

Development and stability analysis of carpal kinematic metrics from 4D magnetic resonance imaging.

To develop MRI-derived carpal kinematic metrics and investigating their stability. The study used a 4D MRI method to track scaphoid, lunate, and capitate movements in the wrist. A panel of 120 metrics for radial-ulnar deviation and flexion-extension was created using polynomial models of scaphoid and lunate movements relative to the capitate. Intraclass correlation coefficients (ICCs) analyzed intra- and inter-subject stability in 49 subjects, 20 with and 29 without wrist injury history. Comparable degrees of stability were observed across the two different wrist movements. Among the total 120 derived metrics, distinct subsets demonstrated high stability within each type of movement. For asymptomatic subjects, 16 out of 17 metrics with high intra-subject stability also showed high inter-subject stability. The differential analysis of ICC values for each metric between asymptomatic and symptomatic cohorts revealed specific metrics (although relatively unstable) exhibiting greater variability in the symptomatic cohort, thereby highlighting the impact of wrist conditions on the variability of kinematic metrics. The findings demonstrate the developing potential of dynamic MRI for assessing and characterizing complex carpal bone dynamics. Stability analyses of the derived kinematic metrics revealed encouraging differences between cohorts with and without wrist injury histories. Although these broad metric stability variations highlight the potential utility of this approach for analyzing carpal instability, further studies are necessary to better characterize these observations.

Intracarpal arthrodesis or proximal row carpectomy in SNAC and SLAC wrist

Objective: To clarify the indications for the choice of operative intervention in patients with SLAC and SNAC wrist and to compare the functional results after proximal carpectomy (PRC) and partial intracarpal arthrodesis with scaphoid excision. Methods: A total of 20 patients underwent four corner fusion intracarpal arthrodesis with scaphoid excision, and 8 patients underwent proximal carpectomy in the period from 2016 to 2023. The mean postoperative follow-up period for patients with intracarpal arthrodesis was 3.2 years and for patients with proximal carpectomy was 3.5 years. Results: Regarding range of motion of the wrist in the flexion-extension axis, the proximal carpectomy patients in our series showed better results than the intracarpal arthrodesis patients, an average of 84% in the PRC patients and 75% in the intracarpal arthrodesis patients relative to the contralateral limb. In the patients with intracarpal arthrodesis, however, we recorded a greater preserved range of motion in the radial-ulnar deviation axis of the wrist. Grip strength was measured at 6 months postoperatively and averaged 72% for the PRC group compared with 83% for patients with intracarpal arthrodesis to the contralateral limb. Conclusion: Both proximal carpectomy and intracarpal arthrodesis are surgical interventions that achieve similar functional outcomes for the treatment of degenerative conditions of the wrist (SLAC/SNAC).

10. COMPARISON OF ERGONOMICS BETWEEN ROBOTIC AND CONVENTIONAL SURGERY: A STUDY OF MUSCLE ACTIVITY AND BODY POSTURE

Abstract Introduction The objective of this study is to compare the ergonomics of surgeons during surgical procedures using the Versius robot (CMR Surgical) and conventional laparoscopic surgery. The study assesses surgeons' body posture and muscle activity to objectively identify ergonomic distinctions between the two surgical approaches. Methods A set of surgeons were asked to perform both tasks in a box trainer and surgical procedures in an experimental model. Laparoscopic tasks and procedures were performed both with the robotic platform and conventionally. During the study, surgeons wore electromyography sensors to measure the activity of 14 muscles. Participants also wore inertial sensors to record body movements. Postures were compared with ergonomic guidelines for conventional and robotic laparoscopic surgery. Results In terms of muscle activity in box trainer and in vivo surgeries, the activity distribution of the gastrocnemius, vastus lateralis, erector spinae and medial trapezius muscles was concentrated around a lower median in robotic procedures compared to conventional ones. However, for the brachioradialis, triceps and upper trapezius, the distribution was concentrated at a higher median for robotic procedures. Regarding surgeon posture, a more ergonomically suitable posture is obtained for flexion-extension of the knee and ulnar-radial deviation of the wrist during robotic surgery. Conclusion The study concludes that the use of robotic surgery improves certain aspects of ergonomics in laparoscopy.

Concurrent validity of inertial measurement units in range of motion measurements of upper extremity: A systematic review and meta-analysis.

Inertial measurement units (IMUs) have proven to be valuable tools in measuring the range of motion (RoM) of human upper limb joints. Although several studies have reported on the validity of IMUs compared to the gold standard (optical motion capture system, OMC), a quantitative summary of the accuracy of IMUs in measuring RoM of upper limb joints is still lacking. Thus, the primary objective of this systematic review and meta-analysis was to determine the concurrent validity of IMUs for measuring RoM of the upper extremity in adults. Fifty-one articles were included in the systematic review, and data from 16 were pooled for meta-analysis. Concurrent validity is excellent for shoulder flexion-extension (Pearson's r=0.969 [0.935, 0.986], ICC=0.935 [0.749, 0.984], mean difference=-3.19 (p=0.55)), elbow flexion-extension (Pearson's r=0.954 [0.929, 0.970], ICC=0.929 [0.814, 0.974], mean difference=10.61 (p=0.36)), wrist flexion-extension (Pearson's r=0.974 [0.945, 0.988], mean difference=-4.20 (p=0.58)), good to excellent for shoulder abduction-adduction (Pearson's r=0.919 [0.848, 0.957], ICC=0.840 [0.430, 0.963], mean difference=-7.10 (p=0.50)), and elbow pronation-supination (Pearson's r=0.966 [0.939, 0.981], ICC=0.821 [0.696, 0.900]). There are some inconsistent results for shoulder internal-external rotation (Pearson's r=0.939 [0.894, 0.965], mean difference=-9.13 (p<0.0001)). In conclusion, the results support IMU as a viable instrument for measuring RoM of upper extremity, but for some specific joint movements, such as shoulder rotation and wrist ulnar-radial deviation, IMU measurements need to be used with caution.

Real-time MRI of the moving wrist at 0.55 tesla.

Magnetic resonance imaging (MRI) using 1.5T or 3.0T systems is routinely employed for assessing wrist pathology; however, due to off-resonance artifacts and high power deposition, these high-field systems have drawbacks for real-time (RT) imaging of the moving wrist. Recently, high-performance 0.55T MRI systems have become available. In this proof-of-concept study, we tested the hypothesis that RT-MRI during continuous, active, and uninterrupted wrist motion is feasible with a high-performance 0.55T system at temporal resolutions below 100 ms and that the resulting images provide visualization of tissues commonly interrogated for assessing dynamic wrist instability. Participants were scanned during uninterrupted wrist radial-ulnar deviation and clenched fist maneuvers. Resulting images (nominal temporal resolution of 12.7-164.6 ms per image) were assessed for image quality. Feasibility of static MRI to supplement RT-MRI acquisition was also tested. The RT images with temporal resolutions < 100 ms demonstrated low distortion and image artifacts, and higher reader assessment scores. Static MRI scans showed the ability to assess anatomical structures of interest in the wrist. RT-MRI of the wrist at a high temporal resolution, coupled with static MRI, is feasible with a high-performance 0.55T system, and may enable improved assessment of wrist dynamic dysfunction and instability. Real-time MRI of the moving wrist is feasible with high-performance 0.55T and may improve the evaluation of dynamic dysfunction of the wrist.

Pronator quadratus repair after volar plating for distal radius fractures: A systematic review and meta-analysis of randomized controlled trials.

The purpose of the current study is to meta-analyze the randomized controlled trials in the literature comparing pronator quadratus repair versus no repair alongside volar plating of distal radius fractures. A search of the PUBMED/MEDLINE, EMBASE, and The Cochrane Library databases was performed. Any randomized con- trolled trials comparing pronator quadratus repair versus no repair alongside volar plating of distal radius fractures were included. The relevant information was collected by 2 blinded reviewers using a predetermined data sheet. Clinical outcomes were compared, with all statistical analyses performed using Review Manager Version 5.3. Five randomized controlled trials with 273 patients were included. There was no significant difference in the range of motion in flexion-extension, ulnar-radial deviation, or pronation-supination. There was a significant difference in favor of the no repair group for Disabilities of the Arm, Shoulder and Hand (DASH) Score (MD [Mean Difference]: 2.63, P < .0001) and pronation strength (MD: 13, P < .0001). Furthermore, there was no significant difference in the visual analog scale score. There were 3 complications relating to pronator quadratus repair, in which patients developed carpal tunnel syndrome requiring a release. There was no significant difference in the re-operation rate. This study found that pronator quadratus repair when performing volar plating for distal radius fractures did not result in a significant improvement in functional outcome, range of motion, or strength. I, Systematic Review of Level 1 Studies, Level I, Therapeutic Study.

Scaphoid, lunate and capitate kinematics in the normal and ligament deficient wrist: A bi-plane X-ray fluoroscopy study

The ligamentous structures of the wrist stabilise and constrain the interactions of the carpal bones during active wrist motion; however, the three-dimensional translations and rotations of the scaphoid, lunate and capitate in the normal and ligament deficient wrist during planar and oblique wrist motions remain poorly understood. This study employed a computer-controlled simulator to replicate physiological wrist motion by dynamic muscle force application, while carpal kinematics were simultaneously measured using bi-plane x-ray fluoroscopy. The aim was to quantify carpal kinematics in the native wrist and after sequential sectioning of the scapholunate interosseous ligament (SLIL) and secondary scapholunate ligament structures. Seven fresh-frozen cadaveric wrist specimens were harvested, and cycles of flexion–extension, radial-ulnar deviation and dart-thrower’s motion were simulated. The results showed significant rotational and translational changes to these carpal bones in all stages of disruptions to the supporting ligaments (p < 0.05). Specifically, following the disruption of the dorsal SLIL (Stage II), the scaphoid became significantly more flexed, ulnarly deviated, and pronated relative to the radius, whereas the lunate became more extended, supinated and volarly translated (p < 0.05). Sectioning of the dorsal intercarpal (DIC), dorsal radiocarpal (DRC), and scaphotrapeziotrapezoid (STT) ligaments (Stage IV) caused the scaphoid to collapse further into flexion, ulnar deviation, and pronation. These findings highlight the importance of all the ligamentous attachments that relate to the stability of the scapholunate joint, but more importantly, the dorsal SLIL in maintaining scapholunate stability, and the preservation of the attachments of the DIC and DRC ligaments during dorsal surgical approaches. The findings will be useful in diagnosing wrist pathology and in surgical planning.

A Comparative Study of 2-Corner, 3-Corner, and 4-Corner Arthrodesis for Midcarpal Arthritis.

Four-corner fusion (4CF) is a common treatment for midcarpal arthritis; however, alternatives including 2-corner fusion (2CF) and 3-corner fusion (3CF) have been described. Limited literature suggests 2CF and 3CF may improve range of motion but have higher complication rates. Our objective is to compare function and patient-reported outcomes following 4CF, 3CF, and 2CF at our institution. Adult patients undergoing 4CF, 3CF, and 2CF from 2011 to 2021 who attended at least one follow-up were included. Four-corner fusion patients were compared with those who underwent either 3CF or 2CF using staple fixation. Outcomes include nonunion rate, reoperation rate, progression to wrist fusion, range of motion, and patient-reported pain, satisfaction, and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. A total of 58 patients met inclusion criteria. There were 49 4CF and 9 2CF or 3CF patients. Nonunion rates, progression to wrist fusion, and repeat surgery for any indication were not significantly different among groups. Range of motion (flexion-extension, radial-ulnar deviation) and grip strength at postoperative visits were not significantly different. Significantly more 4CF patients required bone grafting. Pain, overall satisfaction, and DASH scores were similar. Although prior studies suggest increased risk of nonunion and hardware migration after 2CF/3CF, we did not observe higher complication rates compared with 4CF. Range of motion, strength, and patient-reported outcomes were similar. While 4CF is traditionally the procedure of choice for midcarpal fusion, we found that when using a staple fixation technique, 2CF and 3CF have comparable clinical and patient-reported outcomes yet decrease the need for autologous bone grafting.

THE BIOMECHANICAL ANALYSIS OF A NOVEL IMPLANT FOR SCAPHOLUNATE INTEROSSEOUS LIGAMENT RUPTURE REPAIR

There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed.Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively.The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant.Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact.Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials.Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist.

A Novel Mini-Invasive Technique of Arthroscopic-Assisted Reduction and Robot-Assisted Fixation for Trans-Scaphoid Perilunate Fracture Dislocations.

Perilunate injuries are rare but devastating carpal injuries. The treatment of perilunate injuries remains challenging and contentious. This study aims to describe a novel mini-invasive surgical technique of arthroscopic-assisted reduction and robot-assisted fixation for the treatment of trans-scaphoid perilunate fracture dislocations (PLFDs). We retrospectively reviewed patients with PLFDs after surgical treatment from February 2021 to March 2021. The patients underwent arthroscopic-assisted precise reduction and robot-assisted headless screw fixation. Times of guide wire placement were recorded intraoperatively. Periodic follow-up was performed until union of scaphoid fracture was confirmed. Range of motion of the wrist, grip strength, the Visual Analog Scale (VAS) score, the Mayo Wrist Score, the Quick Disabilities of Arm, Shoulder, and Hand (QuickDASH) score, the Patient-Rated Wrist Evaluation (PRWE), and osteoarthritis were evaluated at the final follow-up. Two male patients presenting with PLFDs with an average age of 24.5 years old (32 and 17 years) were included in this study. Intraoperatively, anatomic reduction of the scaphoid fracture was achieved under arthroscopic guidance. A robotic-assisted single-attempt guidewire insertion was performed for scaphoid fracture and lunotriquetral interval. The CT scans at 8 and 12 weeks showed the union of the scaphoid fracture. At final mean follow-up of 13.5 months, the extension, radial-ulnar deviation, and pronation-supination were consistent with the contralateral side in both patients. One patient experienced mild limited range of motion with the flexion 46° of the injured wrist compared with 81°of the contralateral wrist. The VAS score was 0 and 2. The grip strength was 32 and 26 kg compared with 24 and 42 kg of the contralateral wrist. The PRWE score was 13 and 10 and the QuickDASH score was 2 and 7. The Mayo Wrist Score was 100 and 65. No sign of osteoarthritis was found at the last follow-up. Arthroscopic-assisted reduction and robot-assisted fixation is a viable and promising alternative for the treatment of perilunate fracture dislocations. This technique allows precise reduction and accurate placement of the K-wires/screws into the carpal bones through the optimal biomechanical paths.

Virtual regression-based myoelectric hand-wrist prosthesis control and electrode site selection using no force feedback

Most transradial prosthesis users with conventional “Sequential” myoelectric control have two electrode sites which control one degree of freedom (DoF) at a time. Rapid EMG co-activation toggles control between DoFs (e.g., hand and wrist), providing limited function. We implemented a regression-based EMG control method which achieved simultaneous and proportional control of two DoFs in a virtual task. We automated electrode site selection using a short-duration (90 s) calibration period, without force feedback. Backward stepwise selection located the best electrodes for either six or 12 electrodes (selected from a pool of 16). We additionally studied two, 2-DoF controllers: “Intuitive” control (hand open-close and wrist pronation-supination controlled virtual target size and rotation, respectively) and “Mapping” control (wrist flexion–extension and ulnar-radial deviation controlled virtual target left–right and up-down movement, respectively). In practice, a Mapping controller would be mapped to control prosthesis hand open-close and wrist pronation-supination. Eleven able-bodied subjects and 4 limb-absent subjects completed virtual target matching tasks (fixed target moves to a new location after being “matched,” and subject immediately pursues) and fixed (static) target tasks. For all subjects, both 2-DoF controllers with 6 optimally-sited electrodes had statistically better target matching performance than Sequential control in number of matches (average of 4–7 vs 2 matches, p < 0.001) and throughput (average of 0.75–1.25 vs 0.4 bits/s, p < 0.001), but not overshoot rate and path efficiency. There were no statistical differences between 6 and 12 optimally-sited electrodes for both 2-DoF controllers. These results support the feasibility of 2-DoF simultaneous, proportional myoelectric control.

Design of Parallel Exoskeleton System for Wrist Tremor Suppression

This paper introduces the design of a Parallel Exoskeleton for Wrist Tremor Suppression (PEWTS). The design features dual six degree-of-freedom (DOF) subsystems that aim to be compact and suppress tremors in both radial/ulnar deviation (RUD) and flexion/extension (FE) motions of the wrist. A linear Series Elastic Actuator is employed, to provide compactness and back drivability to the system which would make the orthoses more human-compatible. The presented study focuses on providing a fundamental understanding of the working of PEWTS and investigating its feasibility through kinematic workspace analysis.

Wrist motion is distinct between touch screen and manual or digital devices.

Restricted motion during touch screen device use may contribute to wrist overuse injuries. Wrist radioulnar deviation and extension while using touch screen devices and digital or manual counterparts in male and female medical professional dominant and non-dominant hands were quantified to test the hypothesis that mobile touch screen device use reduces wrist motion. An active motion detection system was used to record wrist motion of 12 participants while: tablet swiping and turning book pages; raising a cell and traditional phone to the ear; texting and typing; and entering numbers on a cell phone and manual calculator. Medial and lateral wrist surface range of motion (ROM) and minimum and maximum wrist radial-ulnar deviation and flexion-extension were quantified. Device, sex and handedness effects were determined (P<0.05). Maximum medial radial deviation and ROM were greater using a cell versus traditional phone. Maximum medial radial deviation was higher in the nondominant wrist during backward tablet swiping and while backward page turning versus tablet swiping. Maximum and minimum medial extension angles and ROM were greater while typing versus texting. Female nondominant hand maximum lateral extension and ROM were greater for typing versus texting and maximum medial extension and lateral extension ROM greater during manual versus cell phone calculator use with handedness combined. Maximum lateral extension and ROM were greater in females versus males using manual calculators. Sex and handedness should instruct touch screen, digital and manual device design and use for optimal performance and injury prevention.

Carpal tunnel volume distribution and morphology changes with flexion-extension and radial-ulnar deviation wrist postures.

Non-neutral wrist postures have been reported to cause decreased carpal tunnel volume (CTV) contributing to impingement of the median nerve and development of carpal tunnel syndrome. Recent analysis found CTV did not change with ±20° flexion-extension (FE), however, CTV decreased with ulnar deviation over the range of -5° to 15° radial-ulnar deviation (RUD). These findings suggest CTV may be too coarse of a measure to reflect the effects of slight non-neutral postures, or that volume is conserved and redistributed due to changes in tunnel morphology with posture. The objective of this study was to assess volume distribution along the length of the carpal tunnel and to quantify regional morphology changes with deviated wrist postures in both FE and RUD. Analysis was performed on a dataset of computed tomography scans collected on ten cadaveric specimens (5 male, 5 female, mean age = 80.7 ± 10.9 years) over a range of FE and RUD postures. The carpal tunnel of each scan was divided into four quartiles of equal length along the tunnel to quantify volume distribution. Volume within the carpal tunnel was seen to redistribute with both FE and RUD. Decreased volume in the distal aspect of the tunnel with flexion and proximal aspect of the tunnel with ulnar deviation may contribute to localized compression of the medial nerve. Measures of mean cross-sectional area, width and depth by quartile provided an indication of the morphology changes associated volume redistribution. Morphology analysis also revealed twisting between the proximal and distal aspects of the tunnel which increased with flexion and ulnar deviation and may further contribute to strain on the median nerve.

Passive wrist deviation to increase the ultrasound identified procedural safe zone in carpal tunnel syndrome: A retrospective cohort study.

Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome. Although prior studies have explored the anatomic changes of the median nerve and carpal arch with different wrist deviations and positionings, the change in safe zone distance between the median nerve and ulnar artery with ulnar or radial wrist deviations has not been adequately investigated. To identify the optimal wrist positioning that increases the safe zone distance between the median nerve and ulnar artery using ultrasound in patients with CTS. Retrospective cohort study. Quaternary medical center multidisciplinary outpatient hand clinic. Twenty five patients (41 wrists) with clinical CTS who received an electrodiagnostic study (EDX) to evaluate CTS within 1 year prior to enrollment. Ultrasound-identified safe zone distance measurements were obtained in each patient between the ulnar aspect of the median nerve and the radial aspect of the ulnar artery with the wrist in neutral radial-ulnar deviation as well as in passive ulnar and radial deviation. The ultrasound-identified safe zone distance with the wrist in each of the three positions. The interstructural safe zone distance was significantly greater when measured in the ulnarly deviated position (1.08 cm) compared with either the neutral (0.61cm, p < .001) or radially deviated positions (0.52 cm, p < .001). Interstructural safe zone distance did not differ between those with normal, mild, moderate, or severe classifications of pathology, or between dominant and nondominant limbs. This study demonstrates that the ultrasound-measured interstructural safe zone distance was significantly greater in the ulnarly deviated position than in either the neutral position or radially deviated position. These findings may lead to improvement in the safety of ultrasound-guided injections.

Wrist Bone Motion during Flexion-Extension and Radial-Ulnar Deviation: An MRI Study.

The wrist joint plays a vital role in activities of daily living. Clinical applications, e.g., therapeutic planning, prosthesis design, and wrist biomechanical analysis, require a detailed understanding of wrist maneuvers and motion. The lack of soft tissue information, motion analysis on limited carpal bones, etc., restrain the investigation of wrist kinematics. In this study, we established 3D models of carpal bones with their cartilages, and revealed the helical axes (HA) of all eight carpal bones for the first time. Both left and right hands at different positions of flexion-extension (FE) and radial-ulnar deviation (RUD) from five subjects were in-vivo imaged through a magnetic resonance imaging device. We segmented all of the bones, including cartilage information in the wrist joint, after which we explored the kinematics of all carpal bones with the HA method. The results showed that the HA of all carpal bones for FE bounded tightly and was mainly located slightly above the radius. During the RUD, carpal bones in the distal row rotated along with wrist movement while the scaphoid, lunate, and triquetrum primarily flexed and extended. Further results reported that the carpal bones translated greater in RUD than in FE. With the generation of more delicate wrist models and thorough investigations of carpal motion, a better understanding of wrist kinematics was obtained for further pathologic assessment and surgical treatment.

Movement preferences of the wrist and forearm during activities of daily living

BackgroundDuring activities of daily living, the main degrees of freedom of the forearm and wrist—forearm pronation-supination (PS), wrist flexion-extension (FE), and wrist radial-ulnar deviation (RUD)—combine seamlessly to allow the hand to engage with and manipulate objects in our environment. Yet the combined behavior of these three degrees of freedom is relatively unknown. PurposeTo provide a characterization of natural forearm and wrist kinematics (joint configuration, movement direction, and speed) during activities of daily living. Study designThis is a descriptive cross-sectional study. MethodsTen healthy subjects performed 24 activities of daily living chosen to represent a wide variety of activities, while we measured their PS, FE, and RUD angles using electromagnetic motion capture. The orientation of the forearm and wrist was represented in the three-dimensional “configuration space” spanned by PS, FE, and RUD. From the time course of forearm and wrist orientation in configuration space, we extracted three-dimensional distributions of joint configuration, movement direction, and speed. ResultsMost joint configurations were focused in a relatively small area: subjects spent roughly 50% of the time in the central 20% of their functional range of motion. Some movement directions were significantly more common than others (p < 0.001); in particular, the direction of the dart-thrower's motion (DTM) was about three times more common than motion perpendicular to it. Most movements were slow: the likelihood of moving at increasing speeds dropped off exponentially. Interestingly, the most common high-speed motion combined the DTM with a twist from pronation to supination. As this motion allows one to pick up an object in front of one's body and bring it to the head, it is essential for self-care. Thus, although many activities of daily living follow the DTM without significant forearm rotation, the greatest importance of the DTM may lie in its combination with forearm rotation. ConclusionsDespite the wide variety of activities, we found evidence of preferred movement behavior, and this behavior showed significant coupling between the wrist and forearm.