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Background: Individuals with pronated feet often experience altered foot biomechanics, leading to increased risk of lower limb injuries. Step width modification has been proposed as a potential intervention to improve foot alignment during gait., Research Question: Does modifying step width influence rearfoot eversion and medial longitudinal arch angle (MLAA) in individuals with pronated feet during walking and running?, Methods: Twenty individuals with pronated feet underwent analysis during walking and running on treadmill, maintaining increased or decreased step width using real-time visual feedback. Three-dimensional motion analysis measured rearfoot eversion and MLAA during the stance phase of gait., Results: Wide step width significantly reduced peak rearfoot eversion during waking (mean difference - with normal step width - (MD) = 3.6°, p < 0.001) and running (MD = 4.4°, p < 0.001), time to peak rearfoot eversion during walking (MD = 16.6 p < 0.001) and running (MD = 13.8°, p = 0.014), rearfoot eversion at touch down (TD) during walking (MD = 1.3°, p = 0.004), rearfoot eversion excursion during running (MD = 4.3°, p < 0.001), and peak MLAA during walking (MD = 2.9°, p = 0.006) and MLAA excursion during running (MD = 4.8°, p = 0.004). By contrast, during running, narrow condition significantly increased peak rearfoot eversion (MD = 3.4°, p < 0.001). During walking, time to peak rearfoot eversion (MD = 16.1, p < 0.001), rearfoot eversion at TD (MD = 1.4°, p = 0.008), rearfoot eversion excursion (MD = 5.9°, p < 0.001), and peak MLAA (MD = 3.4°, p < 0.001) were significantly increased., Significance: This study highlights the potential of step width modification as a simple yet effective intervention to improve foot biomechanics in pronated feet individuals during walking and running. Further research could lead to the development of personalized strategies for pronated feet individuals., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Our study aims to characterize the results of Monteggia fractures treated in our practice and to determine factors associated with good or poor outcomes., Methods: A retrospective review of children aged 17 and under with acute, subacute, or chronic Monteggia fractures who were treated at our institution was performed. The primary outcomes were initial reduction and maintenance of joint reduction, while the secondary outcomes were elbow flexion/extension and forearm supination/pronation., Results: Seventeen patients with Monteggia fractures were identified. Two patients were excluded: 1 was lost to follow-up and 1 had congenital absence of the elbow flexors. Thus, our final cohort was 15 patients (acute n = 3, subacute n = 4, chronic group n = 8). Median final follow-up was 1.9 years (range = 34 days-8 years)., Conclusion: Preoperative range of motion (ROM) was the most important factor in determining postoperative ROM in this cohort of patients with chronic Monteggia fractures. All patients who presented with excellent preoperative ROM, regardless of their timing category, had an excellent ROM outcome. Time from initial injury also played an important role. All patients in the acute and subacute categories had good or excellent postoperative ROM. Patients who were further from the initial injury were more likely to present with worse preoperative ROM and, in turn, had worse outcomes with postoperative ROM., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The distinct and specialized movements performed in different sports disciplines may significantly influence nerve performance, potentially affecting nerve responses and the overall function within the respective athletic activities. The purpose of this study is to find the effect of forearm supination and pronation across the elbow joint on ulnar and median nerve conduction velocity (NCV) in throwers, archers, and non-athletes. A total of 34 participants both male and females were recruited with a body mass index (BMI) between 18.5 and 24.9 kg/m 2 . Nerve conduction study (NeuroStim NS2 EMG/NCV/EP System) was used for measuring ulnar and median NCV across the elbow joint at different angles with the forearm in supination and pronation. Repeated measure analysis of variance (RMANOVA) revealed that there are statistically significant differences in mean values of forearm positions, angles, nerves and groups (p < .05). This study illuminates distinctive NCV variations across diverse athletic groups during forearm supination and pronation movements. Pronation consistently exhibited faster ulnar NCV compared to the median nerve across throwers, archers, and non-athletes, while in supination specific joint positions revealed notable differences within sports groups and nerve function.

Purpose: Depending on its axis, pronation varies from the radius rotation around the steady ulna to the reciprocal adduction of the radius and abduction of the ulna. While there is no question that pronator teres is a central pronation agonist, anconeus's role is not settled. The current investigation comparing palpation and ultrasonography in these two muscles during pronation along the axis capitulum-second digit evolved from a serendipitous finding in a clinical anatomy seminar., Methods: Single-hand palpation and two-transducer ultrasonography over anconeus and pronator teres were used on ten normal subjects to investigate their contraction during pronation around the capitulum-second digit axis. These studies were done independently and blind to the results of the other. The statistical analysis between palpation and ultrasonography was performed with Cohen's kappa coefficient and the χ2 test., Results: On palpation, on resisted full pronation, anconeus contracted in 8/10 subjects and pronator teres in 10/10 subjects. Without resistance, the corresponding ratios were 5/10 and 9/10. On two-transducer ultrasonography, the comparable ratios were 7/10 and 10/10, and 3/10 and 10/10. A fair concordance (Cohen's kappa = 0.21) between palpation and ultrasonography in detecting the simultaneous status of anconeus and pronator teres during resisted full pronation. Anatomic dissection illustrated the elements involved., Conclusions: Plain palpation confirmed by ultrasonography showed the simultaneous contraction of anconeus and pronator teres during resisted pronation in most of the studied subjects. The study suggests that palpation can be helpful in directly studying muscle activity during movement., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Overuse injuries are often caused by pronated foot and the associated abnormal lower-extremity kinematics during dynamic activities. Various patterns of foot kinematics are observed among individuals with pronated feet during dynamic activities, resulting in different dynamic kinematics of the proximal joint. This study aimed to identify the foot kinematic patterns during gait among individuals with pronated feet and evaluate the relationship between these foot kinematic patterns and the hip and knee kinematics. A three-dimensional motion capture system was used to collect data regarding the foot, knee, and hip kinematics during the stance phase of gait of 42 individuals with pronated feet. A hierarchical cluster analysis method was used to identify the optimal number of clusters based on the foot kinematics, including navicular height (NH) at initial contact and dynamic navicular drop (DND). The differences in the cluster and demographic variables were examined. One-dimensional statistical parametric mapping was used to evaluate the differences in the time histories of the NH, knee, and hip kinematics during the stance phase. Three subgroups were identified on the basis of the NH and DND: Cluster 1, moderate NH at initial contact and larger DND; Cluster 2, highest NH at initial contact and smaller DND; and Cluster 3, lowest NH at initial contact and smaller DND. The hip adduction angle of Cluster 1 was significantly higher than that of Cluster 3 from the 0% to 51% stance phases. Further longitudinal studies are needed to clarify the relationship between identified subgroups and the development of overuse injuries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Background: Strengthening the hip and trunk muscles may decrease foot pronation in upright standing due to expected increases in hip passive torque and lower-limb external rotation. However, considering the increased pronation caused by a more varus foot-ankle alignment, subjects with more varus may experience smaller or no postural changes after strengthening., Objective: To investigate the effects of hip and trunk muscle strengthening on lower-limb posture during upright standing and hip passive torque of women with more and less varus alignment., Methods: This nonrandomized controlled experimental study included 50 young, able-bodied women. The intervention group (n = 25) performed hip and trunk muscle strengthening exercises, and the control group (n = 25) maintained their usual activities. Each group was split into two subgroups: those with more and less varus alignment. Hip, shank, and rearfoot-ankle posture and hip passive external rotation torque were evaluated. Mixed analyses of variance and preplanned contrasts were used to assess prepost changes and between-group differences (α = 0.05)., Results: The less-varus subgroup of the intervention group had a reduced rearfoot eversion posture (P = 0.02). No significant changes were observed in the less-varus subgroup of the control group (P = 0.31). There were no significant differences in posture between the control and intervention groups when varus was not considered (P ≥ 0.06). The intervention group had increased hip passive torque (P = 0.001) compared to the control group, independent of varus alignment., Conclusion: Despite the increases in hip passive torque, the rearfoot eversion posture was reduced only in women with a less-varus alignment. Having more foot-ankle varus may prevent eversion reductions., Competing Interests: Declaration of competing interest None, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: To compare pronator quadratus preserving (PQ-P) approaches with PQ dissecting (PQ-D) approaches in volar plate fixation of distal radius fractures (DRFs)., Methods: Three databases were searched on March 10th, 2024. The authors adhered to the PRISMA and R-AMSTAR guidelines and Cochrane Handbook for Systematic Reviews. Data on demographics, fracture classifications, patient reported outcome measures (PROMs), range of motion, radiographic parameters, and complications were extracted., Results: Thirteen studies with a total of 1007 fractures were included. Two of three studies reported lower DASH scores in the PQ-P group between 6 weeks and 3 months postoperative, however no studies reported lower scores in the PQ-P group after 3 months. Three of three studies reported significantly lower VAS scores at 6 weeks postoperative, however no studies reported significant differences after 6 months. Only one of six studies reported significantly greater flexion, extension, and pronation in the PQ-P group. One of four studies reported greater radial deviation in the PQ-P group, while there were no differences in supination or ulnar deviation. One of ten and one of six studies reported greater volar tilt and ulnar variance or radial length, respectively, in the PQ-P group., Conclusion: There is not sufficient evidence supporting the utility of PQ-P approaches over conventional PQ-D approaches for volar plate fixation of DRFs, especially at long-term follow-ups (3+ months). There may be short term benefits with PQ-P approaches, specifically with regards to PROMs in the short-term (< 6 weeks), however there is limited high-quality evidence supporting these findings., Level of Evidence: Level III., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Baseball coaches often focus on the landing position of a pitcher's front foot as a key aspect of mechanics. Furthermore, controversy persists regarding positioning the rear foot on the first base or third base end of the rubber. The purpose of this study was to determine the effect of rear and front foot placement on pitching biomechanics. Our hypotheses were that there would be significant kinematic and kinetic differences associated with foot placement. This was a retrospective review including 144 healthy right-handed adult baseball pitchers divided into groups based on their rear and front foot placements: first base open (1B-Open), first base closed (1B-Closed), third base open (3B-Open), and third base closed (3B-Closed). Two-way ANOVAs detected no statistically significant main effects for kinetic variables but several for kinematic variables. Open pitchers had less shoulder abduction at the time of ball release and greater maximum shoulder internal rotation velocity in comparison with closed pitchers. They also had less forearm pronation at the time of ball release and greater maximum elbow extension velocity. Additional statistically significant results were found; however, low effect sizes may lessen the clinical significance of many of the results.

Background: The traditional scarf osteotomy (TSO) has limited ability to correct the first metatarsal pronation. A novel modification that we refer to as a "dovetailed notch scarf osteotomy" (DNSO) has been developed to enhance the ability to correct coronal plane pronation. The study aimed to observe and compare TSO to DNSO in the treatment of moderate to severe hallux valgus deformity., Methods: This retrospective study included 78 feet that had a TSO and 105 feet that had a DNSO. Minimum follow-up was 24 months. Weightbearing computed tomography (WBCT) and weightbearing anterior-posterior (AP) radiographs were taken preoperatively and at the last follow-up. We measured the intermetatarsal angle (IMA), hallux valgus angle, distal metatarsal articular surface angle on AP radiographs and first metatarsal coronal pronation angle (α angle), tibial sesamoid coronal grading, and first metatarsal length on WBCT. Clinical assessment was done using visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale, Foot and Ankle Ability Measure (FAAM), and the 36-Item Short Form Health Survey (SF-36). The occurrence of postoperative complications was also documented., Results: The DNSO group exhibited a significantly higher correction amount of α angle and IMA (14.3 ± 9.9 and 10.3 ± 4.6 degrees) than the TSO group (8.6 ± 5.9 and 5.4 ± 5.9 degrees) during the final follow-up assessment ( P  < .05).The DNSO group (10.1 [8.0-12.0] degrees and 4.8 [3.9-5.6] degrees) demonstrated significantly smaller α angle and IMA compared with the TSO group (4.8 [3.9-5.6] degrees and 9.5 [7.5-11.5] degrees) at 24 months postsurgery ( P  < .05). The postoperative FAAM activities of daily living and SF-36 physical functioning scores were significantly higher in the DNSO group (97.2 ± 3.3 and 95.7 ± 4.4 points) compared with the TSO group (92.3 ± 3.3 and 87.7 ± 8.7 points) ( P  < .05). Additionally, hallux varus occurred in 1 case in the DNSO group, whereas 4 cases were observed in the TSO group., Conclusion: Two osteotomy methods can effectively correct moderate to severe hallux valgus deformity. Compared with the TSO, the DNSO has stronger correction ability. The most crucial aspect lies in its controllability when correcting first metatarsal pronation and addressing IMA., Level of Evidence: Level III, retrospective comparative study., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Chao Wang, MD, reports support for the present manuscript from National Natural Science Foundation of China (No. 82272473). Disclosure forms for all authors are available online.

Several studies have indicated that Camitz transfer for severe carpal tunnel does not adequately restore thumb opposition. The aim of this study was to determine whether modification of the distal insertion of the transferred palmaris longus tendon could provide more effective opposition. We used 12 fresh-frozen upper extremity specimens. For spatial analysis, we used a three-dimensional motion-tracking device. At 0 N and 5 N of traction force, the pronation angle was significantly larger for the modified procedure than for the conventional procedure. There was no significant difference in the palmar abduction angle between the two groups. The modified palmaris longus tendon insertion on the ulnar side of the thumb metacarpophalangeal joint provides more effective thumb pronation than conventional Camitz opponensplasty in a cadaver model.    ., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Kousuke Iba is an endowed chair at the Department of Musculoskeletal Anti-aging Medicine, Sapporo Medical University.

Introduction: Fractures of the scaphoid are the most common carpal injuries, account for 80-90% of all carpal fractures. 5-15% nonunion of scaphoid fractures were reported even with adequate primary treatment, which probably progresses to osteoarthritic changes several decades later. Researches regarding to scaphoid physiological characteristic in vitro and in vivo and kinds of trials in clinical practice are being kept on going, which contribute much to our clinical practice. With the advancing wrist arthroscopy, 3D-print patient-specific drill guide, and intraoperative fluoroscopic guidance, dorsal approach (mini-invasive and percutaneous technique) is being popular, through which we can implant the screw in good coincidence with biomechanics and with less disturbing tenuous blood supply of the scaphoid. Investigating the noncontact area of the dorsal proximal scaphoid in different wrist positions can facilitate preoperatively estimating insert point of the screw., Materials and Methods: Eight volunteers were recruited to accept CT scans in six extreme wrist positions. The images of DICOM mode were imput into the Mimics analytical system, the segmented scaphoid, lunate and radius were exported in mode of ASCII STL and were opened in the software of Geomagic studio. We created four planes based on anatomic markers on the surface of the radius and scaphoid to confine the proximal scaphoid to form the so-called non-contact regions. We measured and compared the areas in six targeted positions., Results: Amidst six extreme wrist positions, area of the non-contact region in extreme dorsal extension (59.81 ± 26.46 mm 2 ) was significantly the smallest, and it in extreme palmar flexion significantly was largest (170.51 ± 30.44 mm 2 ). The non-contact regions increased in order of dorsal extension, supination, ulnar deviation, radial deviation, pronation and palmar flexion. As for two-group comparison, the non-contact region showed significantly larger (p < 0.05) in palmar flexion than the others except for in pronation individually, and in radial deviation (p < 0.05) than in dorsal extension., Conclusions: Sufficient space was available for the screw started from the dorsal approach despite the wrist positions., (© 2024. The Author(s).)

Arm-cycling is a versatile exercise modality with applications in both athletic enhancement and rehabilitation, yet the influence of forearm orientation remains understudied. Thus, this study aimed to investigate the impact of forearm position on upper-body arm-cycling Wingate tests. Fourteen adult males (27.3 ± 5.8 years) underwent bilateral assessments of handgrip strength in standing and seated positions, followed by pronated and supinated forward arm-cycling Wingate tests. Electromyography (EMG) was recorded from five upper-extremity muscles, including anterior deltoid, triceps brachii lateral head, biceps brachii, latissimus dorsi, and brachioradialis. Simultaneously, bilateral normal and propulsion forces were measured at the pedal-crank interface. Rate of perceived exertion (RPE), power output, and fatigue index were recorded post-test. The results showed that a pronated forearm position provided significantly (p < 0.05) higher normal and propulsion forces and triceps brachii muscle activation patterns during arm-cycling. No significant difference in RPE was observed between forearm positions (p = 0.17). A positive correlation was found between seated handgrip strength and peak power output during the Wingate test while pronated (dominant: p = 0.01, r = 0.55; non-dominant: p = 0.03, r = 0.49) and supinated (dominant: p = 0.03, r = 0.51; don-dominant: p = 0.04, r = 0.47). Fatigue changed the force and EMG profile during the Wingate test. In conclusion, this study enhances our understanding of forearm position's impact on upper-body Wingate tests. These findings have implications for optimizing training and performance strategies in individuals using arm-cycling for athletic enhancement and rehabilitation., (© Journal of Sports Science and Medicine.)

Background: Hallux valgus (HV) is a very common deformity worldwide. Most of the surgical techniques used in the treatment of HV only correct these deformities in two planes, that is sagittal and transverse planes. The importance of the first metatarsal pronation as an etiological factor of hallux valgus is validated by numerous authors and it is usually unaddressed. Few surgical techniques have focused on the correction of rotational deformity of the hallux valgus. We aim to first report a detailed technique and a case series using the Distal Rotational Metatarsal Osteotomy (DROMO) surgical technique, which is less invasive and can address the pronation deformation., Methods: The inclusion period was 6 months finishing in April 2021. The study analyzed the following x-ray parameters: preoperative and postoperative intermetatarsal angle (IMA), preoperative and postoperative hallux valgus angle (HVA), preoperative and postoperative coronal rotation of the first metatarsal according Hardy and Clapham's classification as described by Kim et al., preoperative and postoperative shape of the first metatarsal head as described by Ono et al. RESULTS: 33 patients matched our inclusion and exclusion criteria. Most patients underwent the surgery for the left foot (n = 18), compared to the right foot (n = 15). We found statistically significant differences between preoperative and postoperative IMA (p < 0.001), preoperative and postoperative HVA (p < 0.001). Preoperative and postoperative coronal rotation of the first metatarsal as classified by Hardy and Clapham was significantly different (p < 0.001), as well as preoperative and postoperative shape of the first metatarsal head (p < 0.01)., Conclusions: DROMO can correct the metatarsal rotation through minimal invasive surgery. From our perspective, DROMO technique should be another alternative for HV correction technique which in time can be associated as a local anesthetic technique, DROMO results are attractive for an ambulatory procedure., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study aimed to identify the clinical and biomechanical factors of subjects with excessive foot pronation who are not responsive (i.e., "non-responders") to medially wedged insoles to increase knee adduction external moment. Ankle dorsiflexion range of motion, forefoot-shank alignment, passive hip stiffness, and midfoot passive resistance of 25 adults with excessive bilateral pronation were measured. Also, lower-limb angles and external moments were computed during walking with the participants using control (flat surface) and intervention insoles (arch support and 6° medial heel wedge). A comparison between "responders" (n = 34) and "non-responders" (n = 11) was conducted using discrete and continuous analyses. Compared with the responders, the non-responders had smaller forefoot varus (p = 0.014), larger midfoot passive internal torque peak (p = 0.005), and stiffness measured by the torsimeter (p = 0.022). During walking, non-responders had lower angle peaks for forefoot eversion (p = 0.001), external forefoot rotation (p = 0.037), rearfoot eversion (p = 0.022), knee adduction (p = 0.045), and external hip rotation (p = 0.022) and higher hip internal rotation angle peak (p = 0.026). Participants with small forefoot varus alignment, large midfoot passive internal torque, stiffness, small knee valgus, hip rotated internally, and foot-toed-in during walking did not modify the external knee adduction moment ("non-responders"). Clinicians are advised to interpret these findings with caution when considering the prescription of insoles. Further investigation is warranted to fully comprehend the response to insole interventions among individuals with specific pathologies, such as patellofemoral pain and knee osteoarthritis (OA)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Purpose: To assess whether a correlation between the calcaneal pronation angle and the presence of internal plantar arch overload signs (such as upper-medial spring ligament lesion, posterior tibial tendon tenosynovitis, etc.) could lead to a better understanding of coxa pedis pathology., Material and Methods: One hundred ankle MRIs of consecutive patients were retrospectively reviewed measuring the calcaneal pronation angle and either the presence or absence of internal plantar arch overload signs. Next, the association of overload signs with increasing pronation angle was evaluated to establish a cut-off point beyond which coxa pedis pathology could be defined., Results: The tibial-calcaneal angle values in patients with and without effusion proved to be significantly different (p < 0.0001). The tibial-calcaneal angle values in patients with and without oedema also demonstrated a significant difference (p < 0.0056). Regarding posterior tibial tendon, a significant difference was found between the two groups (p < 0.0001). For plantar fascia enthesopathy, the result was borderline significant (p < 0.054). A linear correlation was found between the value of pronation angle and the extent of spring ligament injury (p < 0.0001). In contrast, no correlation with age was found., Conclusion: In conclusion, the literature associates medial longitudinal plantar arch overload with posterior tibial tendinopathy and spring ligament complex injuries. Our data show that both injuries are highly correlated with increased calcaneal pronation angle, which could be considered a predictive sign of internal plantar arch overload, prior to the development of the associated signs., (© 2024. The Author(s).)

Background: The aim of this study was to compare the effects of four different immobilization methods [single sugar tong splint (SSTS), double sugar tong splint (DSTS), short arm cast (SAC), and long arm cast (LAC)] commonly used for restricting forearm rotation in the upper extremity., Methods: Forty healthy volunteers were included in the study. Dominant extremities were used for measurements. Basal pronation and supination of the forearm were measured with a custom-made goniometer, and the total rotation arc was calculated without any immobilization. Next, the measurements were repeated with the SAC, LAC, SSTS and DSTS. Each measurement was compared to the baseline value, and the percentage of rotation restriction was calculated., Results: The most superior restriction rates were observed for the LAC (p = 0.00). No statistically significant difference was detected between the SSTS and DSTS in terms of the restriction of supination, pronation or the rotation arc (p values, 1.00, 0.18, and 0.50, respectively). Statistically significant differences were not detected between the SAC and the SSTS in any of the three parameters (p values, 0.25; 1.00; 1.00, respectively). When the SAC and DSTS were compared, while there was no significant difference between the two methods in pronation (p = 0.50), a statistically significant difference was detected in supination (p = 0.01) and in the total rotation arc (p = 0.03)., Conclusion: The LAC provides superior results in restricting forearm rotation. The SAC and SSTS had similar effects on forearm rotation. The DSTS, which contains, in addition to the SSTS, a sugar tong portion above the elbow, does not provide additional rotational stability., (© 2024. The Author(s).)

Background: The extensor carpi ulnaris (ECU) tendon has a distinct subsheath at the distal ulna. Symptomatic tears of this subsheath and subluxation of the ECU tendon often require reconstruction. We sought to determine the anatomical constraints of the ECU subsheath., Methods: The ECU subsheath was exposed on 12 fresh-frozen upper extremities. The tip of the ulnar styloid, the distal ulnar joint surface, and the proximal extent of the distal radio-ulnar joint were identified and dimensions measured. Subluxation of the tendon was then assessed with and without an intact subsheath in 9 specimens. The travel of the tendon was measured in pronation through supination and flexion before and after sectioning of the subsheath., Results: The ECU subsheath is 8.9 mm (standard deviation [SD] = 0.8 mm) wide proximally and 9.0 mm (SD = 1.2 mm) distally. The distal ulnar insertion is 0.5 mm (SD = 0.8 mm) proximal to the tip of the styloid, and stretches 10.2 mm (SD = 2.7 mm) proximally. From maximum pronation to maximum supination and flexion, the ECU tendon traveled 3.32 mm (SD = 4.24) medially when the subsheath was intact and 5.42 mm (SD = 5.0 mm) after sectioning. The maximum depth of the ulnar groove was 2.5 mm (1.59-3.56 mm). There was no significant association between changes in ECU subluxation and the depth of the ECU groove (Spearman's rho = 0.25)., Conclusion: The ECU subsheath is roughly 1 cm square stretching proximally from the ulnar styloid. ECU groove depth is not a significant independent predictor of tendon subluxation., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose: The length change of the interosseous membrane (IOM) during forearm rotation has not been fully studied. To explore the meaning of length change in the distal oblique band (DOB), the distal accessory band (DAB), and the proximal, middle, and distal parts of the central band (CBP, CBM, and CBD, respectively), we investigated the length change in these ligaments at maximum pronation, 45° of pronation, neutral position, 45° of supination, and maximum supination in vivo., Methods: The images of the right forearms from 6 healthy volunteers were obtained by computed tomography scanning at the 5 above-mentioned rotation positions. We created 3-dimensional models of the radius and ulna, DOB, DAB, and central band based on the points of origin and insertion. Finally, the length of each ligament was estimated from the points of insertions and origins registered on the 3-dimensional models., Results: The DAB and CBD lengths increased significantly from maximum pronation to 45° of pronation. The DOB length increased significantly from 45° of pronation to neutral position and decreased significantly from 45° of supination to maximum supination. The DAB and CBM lengths increased significantly from neutral position to 45° of supination. The DAB length decreased significantly from 45° of supination to maximum supination. For the CBP, no difference in length was observed during forearm rotation., Conclusions: The DOB becomes taut at neutral position, and the central band, especially the CBP, is nearly isometric. The findings indicate that the DOB may provide the primary stabilization of the distal radioulnar joint and that the central band is the key stabilizer during forearm rotation., Clinical Relevance: Surgeons may pay attention to the DOB when a patient incurs a distal radioulnar joint injury, and the CBP may be the optimal location for IOM reconstruction., (Copyright © 2024 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to quantify the in vivo displacement of bilateral distal radioulnar joints (DRUJs) in resisted pronosupination. We hypothesize that this will demonstrate no appreciable difference between the left and right DRUJ, thus validating the concept of using the uninjured wrist as a control for physical examination as well as dynamic imaging studies., Methods: Thirty-two participants without a history of wrist pathology underwent a dynamic computed tomography (CT) protocol evaluating bilateral forearm rotation in neutral forearm rotation, 60° pronation, and 60° supination, including maximal isometric muscle loading. The DRUJ alignment, specifically the absolute degree and direction of subluxation of the ulna relative to the sigmoid notch, was then assessed using a modification of the radioulnar line method., Results: There was no significant difference in the mean displacement when comparing the right and left sides in neutral, pronation, or supination. The mean displacement was also compared between male and female patients, and there was no statistically significant difference in absolute displacement in neutral (male 0.99 mm vs female 1.38 mm) or supination (male -0.57 mm vs female -0.23 mm). However, the difference in pronation was statistically significant (male 2.69 mm vs female 3.26 mm). Of the 192 sequences, the measurements of displacement of the authors were within 1 mm 86% of the time (166 of 192)., Conclusions: Dynamic CT of bilateral DRUJs in resisted pronation, supination, and neutral demonstrated symmetry between the right and left DRUJ, supporting the concept of using the contralateral side as a control to identify instability in an injured wrist., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Several surgical procedures are used to treat dynamic pronation position of the forearm and flexion deformity of the wrist in cerebral palsy. Postoperative results of pronator teres rerouting were explored, while specially designed postoperative physiotherapy and its outcomes were limited. Herein, we present a case in whom the outcomes of electromyographic biofeedback (EMG-BF) training were assessed after pronator teres rerouting and brachioradialis tendon to extensor carpi radialis brevis tendon transfer combined with derotation osteotomy. The peak value increased, while the resting value decreased for the muscles after the intervention. Range of motion, hand function, manual ability, functional independence, and quality of life levels were improved. In conclusion, EMG biofeedback training may have a positive effect on neuromuscular control of pronator teres and brachioradialis. Free use of the upper extremity and improved manual ability positively affect the activity and quality of life of the patients.

Background: Running on different surfaces, including natural and artificial surfaces, requires different gait mechanics, especially in individuals with foot deformity., Research Question: How muscle activity change during running on the ground and artificial turf in males with pronated and supinated feet?, Methods: In this quasi-experimental study, we assessed a cohort of young male subjects, classified as healthy (n = 10), and with pronated (n = 10) or supinated (n = 10) feet. An electromyographic system was used to record lower limb muscle activity while running on the ground and artificial turf at constant speed (3.2 m/s)., Results: Results demonstrated significant main effects of the "surface" factor for vastus medialis activity during the loading phase (p = 0.040, η 2 =0.147). Paired comparison revealed significantly greater vastus medialis activity while running on artificial grass with respect to the ground. A significant effect of the "group" factor was found for medial gastrocnemius during loading phase (p = 0.020, η 2 =0.250). Paired-wise comparison revealed significantly lower medial gastrocnemius activity in the pronated and supinated feet groups than in the healthy group., Significance: The healthy group may possess better neuromuscular control, allowing them to effectively coordinate the activation of the medial gastrocnemius with other muscles involved in running. Based on these findings, running on artificial turf is useful when the runner would like to strengthen vastus medialis muscle. The runner should carefully choose the running surface according to his/her state and training session goal., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The interosseous membrane of the forearm is an essential structure for the stability of the forearm skeleton, the most important part being the central band. The purpose of this study was to determine if shear wave elastography, a non-invasive ultrasound technique, can be used to measure shear wave speed in the central band and quantify stiffness. Fifteen healthy adult subjects were included (30 forearms). The participants forearms were positioned on an articulated plate, with their hand in neutral, pronated and then supinated positions of 30°, 60° and 90°. The shear wave speed was highest in 90° pronation (4.4 m/s (SD 0.3)) and 90° supination (4.4 m/s (SD 0.27)) indicating maximum stiffness in these positions. Its minimum value was in the neutral position, and either in 30° pronation or supination (3.5 m/s (SD 0.3)). Intra- and interobserver agreement was excellent, regardless of probe positioning or forearm mobilization. This study presents a reliable shear wave elastography measurement protocol to describe the physiological function of the central band of the interosseous membrane in healthy adults. Level of evidence: IV.

This study aimed to analyze anthropometrics and mechanomyography (MMG) signals as forearm flexion, pronation, and supination torque predictors. 25 young, healthy, male participants performed isometric forearm flexion, pronation, and supination tasks from 20 to 100% maximal voluntary isometric contraction (MVIC) while maintaining 90° at the elbow joint. Nine anthropometric measures were recorded, and MMG signals from the biceps brachii (BB), brachialis (BRA), and brachioradialis (BRD) muscles were digitally acquired using triaxial accelerometers. These were then correlated with torque values. Significant positive correlations were found for arm circumference (CA) and MMG root mean square (RMS) values with flexion torque. Flexion torque might be predicted using CA (r = 0.426-0.575), a pseudo for muscle size while MMG RMS (r = 0.441), an indication of muscle activation., (© 2022. The Author(s).)

Purpose: In this study, we observe the therapeutic influence on tendon and bone setting technique, combined with sports training on joint injury., Methods: Using the random number method, 50 research objects with joint injuries were divided into two groups: treatment group and control group, and each group had 25 cases. The treatment group was combined with sports training with tendon and bone setting technique, and the control group was given intermediate frequency electrotherapy combined with forearm brace fixation. The scores of visual analogue scale (VAS), forearm pronation and postrotation activity, integral electromyogram (iEMG), and research object-rated wrist evaluation (PRWE) were evaluated and compared before and after treatment, and the curative effect observation (blind method was used in the evaluation process) and research object satisfaction were evaluated., Results: After the treatment, the VAS score of two groups decreased, forearm pronation and pronation activity increased, iEMG value increased, and PRWE scale score decreased ( p  < 0.05), and compared with the control group, the treatment group's curative effect was better ( p  < 0.05), and compared with the control group, treatment group's total effective rate was higher ( p  < 0.05)., Conclusion: The method of tendon and bone setting combined with sports training could effectively reduce the pain of research objects with joint injury, improve the rotation range of the forearm, increase the recruitment of the pronator muscles, and improve the wrist function of the research objects, and the curative effect was better than that of medium frequency electrotherapy combined with forearm brace fixation., Competing Interests: The author declares that there are no conflicts of interest., (Copyright © 2022 Jihong Yang.)

Running biomechanics research has traditionally occurred in the laboratory, but with the advent of wearable sensors measurement of running biomechanics may shift outside the laboratory. The purpose was to determine if RunScribe™ wearable sensors could detect differences in kinematic, kinetic and spatiotemporal measures during runs at two speeds and on two different surfaces. Fifteen recreational runners (7 males, 8 females; age = 20.0 ± 3.1 years) participated. While wearing sensors on the heels of their shoes, participants completed four 1600 m runs on both track and grass surfaces. On each surface, the first 1600 m was at a self-selected slow speed followed by the second 1600 m at a self-selected fast pace. The sensors quantified several kinetic, kinematic and spatiotemporal measures. Repeated measures ANOVAs compared the effects of surface and speed. The spatiotemporal measures of stride length, cycle time and contact time were predictably affected by increased running speed and increased surface stiffness, as were the kinematic and kinetic measurements of maximum pronation velocity, maximum pronation excursion, impact g, and braking g (p < 0.050). The RunScribe™ sensors identified expected changes in running biomechanics measures at different speeds and on varying surfaces.

Context: Knowledge on how to utilize a kinetic chain approach in foot and ankle rehabilitation is important., Objective: The aim of this study was to investigate the immediate effects of hip-focused neuromuscular exercise on foot pronation and single-leg neuromuscular control., Design: Cross-over study., Setting: University laboratory., Participants: This cross-over study included 44 asymptomatic volunteers with foot pronation., Interventions: All participants performed (1) a hip-focused neuromuscular exercise and (2) a sham exercise in randomized order., Main Outcome Measures: Foot pronation was assessed by the navicular drop test, and lower-extremity neuromuscular control was assessed by the Modified Star Excursion Balance Test and frontal plane projection angle during single-leg squat before and after the experiments., Results: Navicular drop test scores were significantly lower after the hip-focused neuromuscular exercise than after the sham exercise (mean difference [95% CI] = 2.84 [-1.08 to 6.77], P = .003). Modified Star Excursion Balance Test scores in the anterior (P = .008), posteromedial (P = .04), and posterolateral (P < .001) directions were significantly increased after hip-focused neuromuscular exercise. No statistically significant condition × time interaction was found for the frontal plane projection angle (P > .05). However, a main effect of time (P = .003) indicated that less dynamic knee valgus occurred during single-leg squat after both experiments., Conclusions: Hip-focused neuromuscular exercise produced immediate alterations in foot pronation and dynamic balance. Thus, the hip-focused neuromuscular exercise may be used to control foot posture in foot rehabilitation integrated with a kinetic chain approach and could be an effective prevention and treatment strategy.

Background: Partial avulsions of the short and/or long head of the distal biceps tendon cause pain and loss of strength. The goal of the present study was to quantify the loss of supination and flexion strength following a series of surgical releases designed to simulate partial and complete short and long head traumatic avulsions., Methods: Mechanical testing was performed to measure supination moment arms and flexion force efficiency on 18 adult fresh-frozen specimens in pronation, neutral, and supination. The distal biceps footprint length was divided into 4 equal segments. In 9 specimens (the distal-first group), the tendon was partially cut starting distally by releasing 25%, 50%, and 75% of the insertion site. In the other 9 specimens (the proximal-first group), the releases started proximally. Mechanical testing was performed before and after each release., Results: Significant decreases in the supination moment arm occurred after a 75% release in the distal-first release group; the decrease was 24% in pronation (p = 0.003) and 10% in neutral (p = 0.043). No significant differences in the supination moment arm (p ≥ 0.079) or in flexion force efficiency (p ≥ 0.058) occurred in the proximal-first group., Conclusions: A simulated complete short head avulsion significantly decreased the supination moment arm and therefore supination strength., Clinical Relevance: A mechanical case can be made for repair of partial distal biceps tendon avulsions when the rupture involves ≥75% of the distal insertion site., Competing Interests: Disclosure: The authors indicated that no external funding was received for any aspect of this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work (http://links.lww.com/JBJS/G324)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Introduction: Even after reconstructive surgery, it is still difficult for patients with severe burns to achieve independent eating activity. In this project, we customized the forearm pronation's assistant tableware to assist in improvement with eating activities., Methods: From January 2017 to December 2018, 28 patients with severe burns including the hands were recruited. For the patient's independent eating activities, we customized forearm pronation's tableware (forks and spoons). We compared modified Barthel index (MBI) and Visual analogue scale (VAS) of satisfaction under three conditions: no auxiliary tableware, ADL universal cuff, or forearm pronation tableware; to compare the duration and the weight of food spilled during lunch when the patients wore the ADL universal cuff or the forearm pronation's tableware. Differences in MBI (rank data) were tested by the Friedman test, differences in VAS (normal distribution) were tested with One-way ANOVA (Bonferroni), differences in the duration and the weight (normal distribution data) were tested by paired sample t test., Results: After wearing the forearm pronation's assistant tableware, MBI VAS both increased more than when the patients did not wear the auxiliary tableware (all p＜0.05). When the subjects wore forearm pronation tableware, the duration of lunch significantly decreased and the quality of eating activity significantly improved compared to the ADL universal cuff in eating activity (all p＜0.05)., Conclusion: After wearing the forearm pronation's assistant tableware, the patients with severe burns completely or almost completely accomplished independent eating, the duration was decreased, and during eating activity the quality and the satisfaction were improved., Clinical Trial Registration: Chinese Clinical trial registry, ChiCTR1800019963., (Copyright © 2020 Elsevier Ltd and ISBI. All rights reserved.)

Objective:  Cats rely on their forelimb mobility for everyday activities including climbing and grooming. Supination and pronation of the forelimb in cats are considered to primarily involve the antebrachium, rather than the carpus. Therefore, our null hypothesis was that there would be no movement of the carpal bones (radial carpal bone, ulnar carpal bone and accessory carpal bone) relative to the ulna during supination and pronation., Study Design:  Eight feline cadaveric forelimbs were rotated from supination to pronation in a jig and computed tomography was performed in the neutral, supinated and pronated positions. The individual carpal bones were segmented from computed tomography images of the supinated and pronated scans in each of the eight specimens. A feline ulna coordinate system was established and used to quantify the translations and rotations between bones of the proximal carpal row and antebrachium., Results:  After the carpus was rotated from the initial supinated position into pronation, there was significant translation (x, y and z axes) and rotation (x and y axes) of the proximal row of carpal bones based on absolute magnitude values. Given the differences in translations and rotations of the proximal row of carpal bones, our null hypothesis was rejected., Conclusion:  The proximal row of carpal bones translate and rotate independently from the ulna in the cat during pronation of the antebrachium. This may have future implications in the diagnosis and management of feline carpal injuries involving the antebrachiocarpal joint., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: The aim of this study was to evaluate the interexaminer and intraexaminer reliability of classification with the Viladot method of plantar impression obtained by means of a footprinting mat., Methods: Footprints were taken from 40 participants using a footprinting mat. The images were subjected to analysis by 3 independent examiners. To investigate intraexaminer reliability, the analysis was repeated by 1 of the examiners 1 week later., Results: Excellent intraexaminer reliability was found (κ = 1.0; 95% confidence interval [CI], 0.77-1.0; P < .00). For interexaminer reliability, in the right foot high concordance was found for typical feet (κ p  = 0.76; 95% CI, 0.58-0.93; P < .00) and excellent concordance for cavus feet and flat feet (respectively: κ p  = 0.86; 95% CI, 0.68-1.0; P < .00; and κ p  = 0.81; 95% CI, = 0.63-0.99; P < .00). In the left foot high concordance was observed between the 3 evaluators for typical feet and cavus feet (respectively: κ p  = 0.75; 95% CI, 0.57-0.93; P < .00; and κ p  = 0.69; 95% CI, 0.51-0.87; P < .00) and excellent concordance for flat feet (κ p  = 1.0; 95% CI, 0.82-1.0; P < .00)., Conclusion: The Viladot method is reliable for analyses involving 1 or more examiners, presenting excellent intraexaminer reliability and high to excellent interexaminer reliability. The Viladot method is a reliable (replicable and consistent) instrument, that is, its repeated application to the same subject produces similar results., (Copyright © 2020. Published by Elsevier Inc.)

Objective: To determine how foot structure and lower limb function differ between individuals with and without midfoot osteoarthritis (OA)., Design: Electronic databases were searched from inception until May 2020. To be eligible, studies needed to (1) include participants with radiographically confirmed midfoot OA, with or without midfoot symptoms, (2) include a control group of participants without radiographic midfoot OA or without midfoot symptoms, and (3) report outcomes of foot structure, alignment, range of motion or any measures of lower limb function during walking. Screening and data extraction were performed by two independent assessors, with disagreements resolved by a third independent assessor. The methodological quality of included studies was assessed using the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies., Results: A total of 1,550 records were screened by title and abstract and 11 met the inclusion criteria. Quantitative synthesis indicated that individuals who had midfoot OA had a more pronated foot posture, greater first ray mobility, less range of motion in the subtalar joint and first metatarsophalangeal joints, longer central metatarsals and increased peak plantar pressures, pressure time integrals and contact times in the heel and midfoot during walking. Meta-analysis could not be performed as the data were not sufficiently homogenous., Conclusions: There are several differences in foot structure and lower limb function between individuals with and without midfoot OA. Future research with more consistent case definitions and detailed biomechanical models would further our understanding of potential mechanisms underlying the development of midfoot OA., (Copyright © 2020 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Background: The purpose of this study was to report the results of metaphyseal and diaphyseal ulnar shortening osteotomies (USO) for the treatment of ulnar abutment syndrome (UAS). Methods: From 2011 to 2016, we performed metaphyseal USO in 8 patients (8 wrists) and diaphyseal USO in 6 patients (7 wrists). The results were investigated in terms of bone union and cast immobilization, wrist and forearm range of motion (ROM). The mean follow-up duration was 29 months. Results: All 14 patients had bone union. The mean duration of bone union in metaphyseal USO and diaphyseal USO were 3.5 months and 4.3 months and the duration of cast immobilization after surgery were 24.2 days and 29.2 days. The mean forearm ROM (degree) were 134.3 (pronation/supination: 66.7/67.6) and 169.3 (pronation/supination: 84.3/85.0) at 3 months after surgery and 173.4 (pronation/supination: 86.0/87.4) and 172.8 (pronation/supination: 87.1/85.7) at 6 months after surgery. Conclusions: The results from this study suggest that metaphyseal osteotomies are an effective alternative to diaphyseal osteotomies for the treatment of ulnar abutment syndrome. Although metaphyseal osteotomies were associated with temporary decrease of pronation, this discrepancy resolved at 6 months postoperatively. Metaphyseal USO has the potential to promote primary bone union and appears to be an alternative treatment for UAS.

Background: Little attention has been paid to foot structural factors and ground reaction force in hallux valgus. Investigating the structural factors in detail and determining their biomechanical effects can help to better manage hallux valgus., Methods: In this case-control study, 120 females, 90 hallux valgus and 30 healthy, were recruited. Hallux valgus grades (mild, moderate, severe), first metatarsal mobility, foot pronation, hallux rotation, and pain were assessed by clinical tests. Ground reaction forces were measured in barefoot and shod conditions for both feet and analyzed using mixed within-between MANOVA. The association between structural factors and pain with force was analyzed using Spearman correlation coefficient., Results: The frequency of foot structural factors and pain severity were reported in hallux valgus grades. A significant difference was seen in the force values between groups (P<0.001). Bonferroni post hoc test indicated that the mean of the first peak for the severe group was significantly higher than the mild group (P=0.013) and the mean of second peak for the moderate group was higher than that of the healthy group (P=0.009). The force values were affected by wearing shoe (P<0.001) but not by foot side (P=0.086). There was a medium, positive correlation between the hallux rotation and force in the moderate group (r=0.39, P=0.03) and also between the pronation and force in the severe group (r=0.36, P=0.04)., Conclusion: Foot structural factors, pain, and force were different in each hallux valgus grads. Similar force in both feet, and increased force by wearing shoe were seen. The relationship between the pronation and hallux rotation with force revealed the importance of these factors from the biomechanical viewpoint., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: To test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility., Methods: A two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18-40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility ( high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks., Results: Of 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%)., Conclusion: Midfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain., Trial Registration Number: ACTRN12614000260628., Competing Interests: Competing interests: BV reports grants from Commonwealth of Australia National Health and Medical Research Council (Ref: 631717) and from Vionics International for this research. MM is supported by an Australian Postgraduate Award. BV and TM are voluntary (non-compensated) members by invitation on the Vasyli Think Tank., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Driving a motor vehicle needs a specific joint mobility and yet only limited knowledge exists regarding the necessary ankle range of motion. The goal of this study is to characterize the sequence and range of ankle motion., Methods: The arc of plantarflexion/dorsiflexion and supination/pronation was recorded in the right and left ankle using electrogoniometers while thirty laps were driven by fifteen healthy participants around a course in a manual transmission car with a left sided steering wheel. The driver was required to perform the following maneuvers during each lap: (I) Vehicle acceleration and gear change, (II) Sudden evasion, (III) Routine turning, (IV) Rapid turning, (V) Vehicle acceleration followed by emergency braking., Results: Driving required the right ankle to plantarflex 13±9 and dorsiflex 22±7 while supinating 15±7 degrees and pronating minimally. The left ankle plantarflexed 19±10and dorsiflexed 17±10 while supinating 15±7 degrees and pronating minimally. The right ankle dorsiflexed significantly more (p=0.00), and yet the left ankle had a significantly higher maximum plantarflexion and range of plantarflexion/dorsiflexion (p=0.00). Emergency braking resulted in a significantly higher maximum plantarflexion as well as plantarflexion/dorsiflexion range when compared to other maneuvers., Conclusion: This study describes the range of ankle motion identified to drive a car with a manual transmission and a left-sided steering wheel. The right and left ankle exhibit different arcs of motion during driving. This knowledge may assist when evaluating a patient's driving capability. Further studies are needed to investigate whether movement restrictions impair driving., Level of Evidence: Basic science study., (Copyright © 2020 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.)

Objective: Although Essential Tremor is one of the most common movement disorders, we do not currently know which muscles are most responsible for tremor. Determining this requires multiple steps, one of which is characterizing the distribution of tremor among the degrees of freedom (DOF) of the upper limb., Methods: Upper-limb motion was recorded while 22 subjects with ET performed postural and kinetic tasks involving a variety of limb configurations. We calculated the mean distribution of tremor among the seven DOF from the shoulder to the wrist, as well as the effect of limb configuration, repetition, and subject characteristics (sex, tremor onset, duration, and severity) on the distribution., Results: On average, kinetic tremor was greatest in forearm pronation-supination and wrist flexion-extension, intermediate in shoulder internal-external rotation and wrist radial-ulnar deviation and then shoulder flexion-extension and elbow flexion-extension, and least in shoulder abduction-adduction. The average distribution of postural tremor was similar except for forearm pronation-supination, which played a smaller role than in kinetic tremor. Limb configuration and subject characteristics did significantly affect tremor, but practically only in forearm pronation-supination and wrist flexion-extension. There were no significant differences between repetitions, indicating that the distribution was consistent over the duration of the experiment., Conclusions: This paper presents a thorough characterization of tremor distribution from the shoulder to the wrist., Significance: Understanding which DOF exhibit the most tremor may lead to more targeted peripheral tremor suppression., (Copyright © 2020 International Federation of Clinical Neurophysiology. All rights reserved.)

This article reviews the anatomy and mechanics of pronation and supination (axial rotation) of the forearm through the distal radioulnar joint (DRUJ), and the proximal radioulnar joint (PRUJ). Injuries to the bones and/or ligaments of the forearm, wrist, or elbow can result in instability, pain, and limited rotation. Acute dislocations of the DRUJ commonly occur along with a fracture to the distal radius, radial metadiaphysis, or radial head. These injuries are all caused by high-energy trauma. Outcomes are predicated on anatomic reduction and restoration of stability to the DRUJ and PRUJ with or without ligamentous repair or reconstruction., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: We aim to propose a novel method of evaluating the degree of rhythmic irregularity during repetitive tasks in Parkinson's disease (PD) by using autocorrelation to extract serial perturbation in the periodicity of body part movements as recorded by objective devices., Methods: We used publicly distributed sequential joint movement data recorded during a leg agility task or pronation-supination task. The sequences of body part trajectory were processed to extract their short-time autocorrelation (STACF) matrices; the sequences of single task conducted by participants were then divided into two clusters according to their similarity in terms of their STACF representation. The Unified Parkinson's Disease Rating Scale sub-score rated for each task was compared with cluster membership to obtain the area under the curve (AUC) to evaluate the discrimination performance of the clustering. We compared the AUC with those obtained from the clustering of the raw sequence or short-time Fourier transform (STFT)., Results: In classifying the pose estimator-based trajectory data of the knee during the leg agility task, the AUC was the highest when the STACF sequence was used for clustering instead of other types of sequences with up to 0.815, being comparable to the results reported in the original analysis of the data using an approach different from ours. In addition, in classifying another dataset of accelerometer-based trajectory data of the wrist during a pronation-supination task, the AUC was again highest up to 0.785 when clustering was performed using the STACF rather than other types of sequence., Conclusion: Our autocorrelation-based method achieved a fair performance in detecting sequences with irregular rhythm, suggesting that it might be used as another evaluation strategy that is potentially widely applicable to qualify the disordered rhythm of PD regardless of the kinds of task or the modality of devices, although further refinement is needed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Background: Older adults are known to have more pronated foot posture and decreased toe flexor strength (TFS), as well as decreased mobility in daily life compared to young adults. Although foot posture is reported to be an influential factor for walking biomechanics in young adults, there is less information on this subject in older adults. Age-related reduction in TFS is shown to be associated with impairments of functional performance, but it is poorly understood whether foot posture influences the relationships between TFS and functional performances. Therefore, the present study aimed to elucidate this concern by examining older women., Methods: Seventy community-dwelling older women (76.8 ± 4.4 years) voluntarily participated in this study. Foot posture was evaluated by the 6-item foot posture index (FPI). Based on the FPI score, participants were allocated to pronated, neutral, or supinated group (n = 33, 26, and 11, respectively). TFS was assessed using a toe grip dynamometer in a seated position. Scores of 30-s chair stand, timed up-and-go, 5-m comfortable-speed walking, and static balance tests were determined to evaluate functional performances. Pearson's correlation coefficients were computed to examine the relationships between TFS and functional performances in each group., Results: TFS positively correlated with comfortable walking speed in the pronated (r = 0.37, p = 0.03) and supinated (r = 0.76, p < 0.001) groups, but not in the neutral group (r = 0.17, p = 0.42). For the two significant relationships, an analysis of covariance showed that there was no significant difference between the pronated and supinated groups in the slopes of the regression lines, suggesting a similar relative contribution of TFS to comfortable walking speed between the two groups. In addition, TFS tended to negatively correlate with timed up-and-go time in the pronated (r = - 0.32, p = 0.07) and supinated (r = - 0.56, p = 0.08) groups, and positively correlate with 30-s chair stand score in the pronated group (r = 0.31, p = 0.08)., Conclusions: The present study indicates that TFS would be associated with mobility, walking performance in particular, in older women with pronated and supinated feet but not with neutral feet.

Objective: To investigate the relationship between the right and left foot posture in terms of body mass index (BMI), sex, and age in adolescents aged 10 to 14., Methods: A total of 1400 adolescents were included. For assessment, the Foot Posture Index (FPI-6) was used. Each foot was assessed and ranked as supinated, normal, or pronated by the sum of the FPI-6 criteria. Each criterion was scored on a scale of -2 to +2, with negative for supinated and positive for pronated posture. A linear mixed model with repeated measures was used for statistical analysis., Results: Sex, BMI, and right and left foot are associated with FPI-6. The total score attributed for male sex (β = 0.29, P = .04) and the left foot (β = 0.73, P < .001) was higher (male right foot: mean ± standard deviation [SD], 3.09 ± 2.84, male left foot: 3.76 ± 2.80; female right foot: mean ± SD, 2.28 ± 2.61, female left foot: 3.45 ± 2.66; laterality for left foot: mean ± SD, 3.55 ± 2.71, laterality for right foot: mean ± SD, 2.82 ± 2.7). On the other hand, the correlation coefficient for the BMI was negative (β = -0.08, P = < .001), which means that the higher the BMI the lower the score attributed to the FPI-6., Conclusions: The FPI-6 is positively related to the male sex and the left foot-that is, the predicted score is higher, so the feet tend to present with a tendency to pronation. Although BMI is associated with FPI-6, it was not possible to establish a relationship between high BMI and pronation of the feet., (Copyright © 2020. Published by Elsevier Inc.)

Background: Management of longitudinal forearm instability remains challenging. Chronic forearm stability may be overcome by reconstruction of the interosseous ligament (IOL). Despite the bands of the IOL being inseparable, studies of the IOL have focused on the central band (CB), but have neglected the proximal (PB) and distal (DB) bands. The purpose of this study was to characterize the bio-mechanical properties of the IOL., Materials and Methods: Twelve frozen specimens from individuals of both sexes were bio-mechanically analyzed using a custom-designed jig operated at constant angular speed to simulate forearm rotation. Strain was measured during dynamic forearm simulation using a motion tracking system., Results: The average strain of the CB, PB, and DB during forearm simulation were 0.08 ± 0.04, 0.83 ± 0.47, and 0.65 ± 0.23 mm (p < 0.001). The IOL was generally shortest during maximal pronation and increased as the forearm was rotated to a neutral position. The strain of the CB remain constant during forearm rotation and was the lowest at full pronation to 20° pronation position. Throughout forearm rotation, the strain of the CB remained constant, whereas the strain of the PB and DB fluctuated., Conclusions: The PB, CB, and DB of the forearm IOL have different bio-mechanical properties. CB maintained a constant rotational strain throughout forearm rotation. Strain on the CB was significantly lower than strains on the PB and DB. By contrast, strains on the PB and DB varied, suggesting that their roles differ from those of the CB. When CB reconstruction is needed, graft should be tensioned at 20° forearm pronation to gain optimum tension.

Background: The interaction of functional and mechanical deficits in chronic ankle instability remains a major issue in current research. After an index sprain, some patients develop sufficient coping strategies, while others require mechanical support. This study aimed to analyze persisting functional deficits in mechanically unstable ankles requiring operative stabilization., Methods: We retrospectively analyzed the functional testing of 43 patients suffering from chronic, unilateral mechanical ankle instability (MAI) and in which long-term conservative treatment had failed. Manual testing and arthroscopy confirmed mechanical instability. The functional testing included balance test, gait analysis, and concentric-concentric, isokinetic strength measurements and was compared between the non-affected and the MAI ankles., Results: Plantarflexion, supination, and pronation strength was significantly reduced in MAI ankles. A sub-analysis of the strength measurement revealed that in non-MAI ankles, the peak pronation torque was reached earlier during pronation (maximum peak torque angle at 20° vs. 14° of supination, p < 0.001). Furthermore, active range of motion was reduced in dorsiflexion and supination. In balance testing, patients exhibited a significant increased perimeter for the injured ankle (p < 0.02). During gait analysis, we observed an increased external rotation in MAI (8.7 vs. 6.8°, p<0.02)., Conclusions: This study assesses functional deficits existent in a well-defined population of patients suffering from chronic MAI. Impairments of postural sway, gait asymmetries, and asymmetric isokinetic strength can be observed despite long-term functional treatment. The finding that pronation strength is particularly reduced with the foot in a close-to-accident position indicates potential muscular dysfunction in MAI. Possibly, these deficits alongside the underlying mechanical instability characterize patients requiring mechanical stabilization.

Purpose: This study investigated the length changes of the anterior bundle of the medial collateral ligament (AMCL) and the lateral ulnar collateral ligament (LUCL) in forearm pronation and supination under axial load in vivo., Methods: Six healthy volunteers (2 males and 4 females, the average age of 44.6 years) were included in the study. CT scan of elbow joints was obtained at positions of forearm pronation and supination before and after load with the elbow extension. Mimics, Geomagic Studio, 3-matic Medical and Geometry Sketchpad were used to reconstruct three-dimensional models and analyze length changes of AMCL and LUCL. The AMCL and LUCL were divided, respectively, to three parts: the medial part, the middle part and the lateral part., Results: Our results showed the length of the medial and middle parts of the AMCL significantly decreased from pronation to supination without load (0.46 mm, P < 0.05 and 0.43 mm, P < 0.05). With load, the length of the medial part and the middle of the AMCL significantly decreased from pronation to supination (0.62 mm, P < 0.05 and 0.44 mm P < 0.05). However, the length of the LUCL almost remained static for the forearm pronation and supination regardless of the axial load., Conclusion: The results showed that tension of the AMCL increases in forearm pronation, and increased tension on the ligament during impact may pave the way to injury. The AMCL of elbow may be easier to be injured in forearm pronation.

Objective: To analyse the influence of muscle fibre axis on the degree of crosstalk in mechanomyographic (MMG) signals during sustained isometric forearm flexion, pronation and supination exercises performed at 80% maximum voluntary contraction (MVC) at an elbow joint angle of 90°., Methods: MMG signals in longitudinal, lateral and transverse directions of muscle fibres were recorded from the elbow flexors of twenty-five male subjects using triaxial accelerometers. Cross-correlation coefficients were used to quantify the degree of crosstalk in all nine possible pairs of fibre axes, all muscle pairs and all exercises., Results: MMG root mean square (RMS) was statistically significant among the fibre axes (p<0.05, η2=0.17- 0.34) except for biceps brachii and brachioradialis in supination and brachialis in flexion. Overall mean crosstalk values in the three muscle pairs (biceps brachii & brachialis, brachialis & brachioradialis and brachioradialis & biceps brachii) were found to be 6.09-52.17%, 4.01-61.42% and 2.16-51.85%, respectively. Crosstalk values showed statistical significance among all nine axes pairs (p<0.05, η2=0.16-0.51) except for biceps brachii & brachialis during pronation. The transverse axes pair generated the lowest mean crosstalk values (2.16-9.14%)., Conclusion: MMG signals recorded using accelerometers from the transverse axes of muscle fibres in the elbow flexors are unique and yield the least amount of crosstalk., Competing Interests: The authors have no conflict of interest.

The topspin tennis forehand drive has become a feature of modern game; yet, as compared to the serve, there has been little research analysing its kinematics. This is surprising given that there is considerably more variation in the execution of the topspin forehand. Our study is the first to examine the amplitude of upper limb joint rotations that produce topspin in the forehand drives of 14 male competitive tennis players using video-based motion analysis. Humerothoracic abduction ( - )/adduction (+), extension ( - ) /flexion (+), and external ( - )/internal (+) rotation, elbow extension ( - ) /flexion (+) and forearm supination ( - )/pronation (+), wrist extension ( - )/flexion (+) and ulnar ( - )/radial ( - ) deviation were computed. Our findings revealed that the generation of topspin demanded more humeral extension and forearm pronation but less humeral internal rotation angular displacement during the forwardswing. The follow-through phase of the topspin shot was characterised by greater humeral internal rotation and forearm pronation, and reduced humeral horizontal adduction when compared to the flat shot. This study provides practitioners with a better understanding of the upper limb kinematics associated with the topspin tennis forehand drive production to help guide skill acquisition interventions and physical training.

We have previously proposed a model of motor lateralization that attributes specialization for predictive control of intersegmental coordination to the dominant hemisphere/limb system, and control of limb impedance to the non-dominant system. This hypothesis was developed based on visually targeted discrete reaching movement made predominantly with the shoulder and elbow joints. The purpose of this experiment was to determine whether dominant arm advantages for multi-degree of freedom coordination also occur during continuous distal movements of the wrist that do not involve visual guidance. In other words, are the advantages of the dominant arm restricted to controlling intersegmental coordination during discrete visually targeted reaching movements, or are they more generally related to coordination of multiple degrees of freedom at other joints, regardless of whether the movements are discrete or invoke visual guidance? Eight right-handed participants were instructed to perform alternating wrist ulnar/radial deviation movements at two instructed speeds, slow and fast, with the dominant or the non-dominant arm, and were instructed not to rotate the forearm (pronation/supination) or move the wrist up and down (flexion/extension). This was explained by slowly and passively moving the wrist in each plane during the instructions. Because all the muscles that cross the wrist have moment arms with respect to more than one axis of rotation, intermuscular coordination is required to prevent motion about non-instructed axes of rotation. We included two conditions, a very slow condition, as a control condition, to demonstrate understanding of the task, and an as-fast-as-possible condition to challenge predictive aspect of control, which we hypothesize are specialized to the dominant controller. Our results indicated that during as-fast-as-possible conditions the non-dominant arm incorporated significantly more non-instructed motion, which resulted in greater circumduction at the non-dominant than the dominant wrist. These findings extend the dynamic dominance hypothesis, indicating that the dominant hemisphere-arm system is specialized for predictive control of multiple degrees of freedom, even in movements of the distal arm and made in the absence of visual guidance.

Objective: To evaluate biomechanical measures in runners with and without chronic ankle instability (CAI) using wearable sensors during two 1600 m track runs at a slow- and fast-pace., Design: Observational case-control., Setting: Field., Participants: 18 recreational runners (CAI: n = 9; Healthy: n = 9) with rearfoot strike patterns., Main Outcome Measures: Pronation excursion, maximum pronation velocity, peak braking g, peak impact g, contact time, cycle time, and stride length of every step of two 1600 m runs were collected using RunScribe™ sensors and binned to each 400 m lap (Lap 1 to Lap 4)., Results: Significant group-by-lap interactions were identified for contact time (p = .05) during the slow-intensity run. The CAI group had greater contact time (p = 0.05) that progressively increased with distance completed. CAI group also had higher impact g than the control group throughout the slow-intensity run (p = .03). During the fast-intensity run, significant group by lap interaction was observed for pronation excursion with the CAI group exhibiting less pronation excursion than the healthy group as the run progressed (p = .002)., Conclusions: Regardless of speed, runners with CAI demonstrated altered gait mechanics compared to healthy controls. During the higher intensity run, decreased pronation excursion was observed in the CAI group and differences became more prominent as the distance increased., Competing Interests: Declaration of competing interest None declared., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: The flexor carpi radialis H-reflex recordings were more robust when the participants were in a sitting position with forearm pronation than with forearm supination. The reliability of flexor carpi radialis recordings obtained with the participant in sitting posture with forearm supination is well established. However, similar reliability utilizing a sitting posture with forearm pronation has not been established. The purpose of this study was to establish the intra and intersession reliabilities of flexor carpi radialis H-reflex recordings acquired with the participants in a sitting with forearm pronation. Materials and methods: The flexor carpi radialis maximum H-reflex amplitude and latency were recorded unilaterally in twenty participants. The forearm was positioned in either a supination or a pronation position on two separate days. Four traces were recorded, and the intraclass correlation coefficients were calculated. Results: The intrasession intraclass correlation coefficients of the four traces of the flexor carpi radialis H-reflex amplitude during pronation on days 1 (0.96) and 2 (0.94) were more consistent than those acquired during supination on days 1 (0.78) and 2 (0.93). The intersession intraclass correlation coefficients of the average traces of the flexor carpi radialis H-reflex amplitude during pronation between days 1 and 2 were more consistent (0.9) than those during supination (0.55). Conclusions: The flexor carpi radialis H-reflex recordings acquired with the participant in a sitting position are more reliable with forearm pronation than with supination within and between sessions. These results should encourage clinicians and researchers to use this position when examining the neuromuscular function of the upper extremities in healthy individuals and those with neuromuscular disorders.

Forearm deformities are often observed in patients with hereditary multiple osteochondroma, resulting in functional disability and cosmetic impairment. The aim of this study was to assess clinical and radiological outcomes after corrective osteotomy of the radius (COR). We performed a retrospective analysis of clinical and radiologic data from patients with forearm deformities who underwent COR combined with osteochondroma resection between 1978 and 2015. Seventeen patients (17 forearms) were included. The mean (range) age at surgery was 11.8 years (3.2-14.4), and the mean interval between surgery and last follow-up was 8.2 years (2-34.2). Range of motion was moderately increased and postoperative radiological assessments found significant improvements in ulnar variance, radial articular angle, bowing of the radius, and carpal slip. At last follow-up, a loss of ulnar variance correction was noted in 11 cases (mean loss: 4mm). The mean score on the Quick Disabilities of the Arm, Shoulder and Hand self-administered questionnaire was 13.9. Our results show that a forearm deformity in a patient with hereditary multiple osteochondroma is an appropriate indication for COR combined with osteochondroma resection and should be performed at the end of growth. This simple, safe technique corrects bowing of the radius and radius-ulna length discrepancy and could limit the risk of radial head dislocation. LEVEL OF EVIDENCE: IV., (Copyright © 2019 SFCM. Published by Elsevier Masson SAS. All rights reserved.)

Although distal radius fractures (DRF) are frequent, the management of associated ulnar styloid process (USP) lesions is still controversial. According to recent studies, a fracture of the USP does not appear to affect functional outcomes after treatment of a DRF with plate fixation. We sought to compare the impact of a USP fracture on pronation and supination strength in isometric and isokinetic tests. We included patients with a DRF who underwent volar locking plate fixation. We divided our population into three groups: one group consisted of patients who had a fracture of the USP base, one group composed of patients without USP fracture or with a distal ulnar fracture only, and a control group composed of subjects with normal wrists. Inclusion criteria included an age of 18 to 50 years and a minimum follow-up of 10 months post-surgery. The main exclusion criteria were complex intraarticular fractures and postoperative complications. The assessment was based on clinical examination and recording of forearm rotation strength during pronation and supination in isokinetic and isometric tests. The ratio between the operated and contralateral sides was compared for each patient. Thirty-six participants were included (mean age 31.1±4.5 years). The mean postoperative follow-up was 17.9±6.9 months. Participants with a USP fracture differed from other participants in their peak torque on the isokinetic test at 45°/s for pronation and supination, but not on isokinetic tests at 120°/s or in isometric tests. Isokinetic tests revealed a decrease in pronation-supination strength during sustained effort for patients with associated basal USP fractures. These findings may have clinical implications for management of the USP but need to be specified with further study. LEVEL OF EVIDENCE: prognostic study level III., (Copyright © 2019 SFCM. Published by Elsevier Masson SAS. All rights reserved.)