Clinical and biomechanical characteristics of responders and non-responders to insoles in individuals with excessive foot pronation during walking.

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).

Neuromechanical Differences between Pronated and Supinated Forearm Positions during Upper-Body Wingate Tests.

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.

Reductions in rearfoot eversion posture due to proximal muscle strengthening are dependent on foot-ankle varus alignment.

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.

In vivo non-contact regions of proximal scaphoid in six extreme wrist positions.

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 mm2) was significantly the smallest, and it in extreme palmar flexion significantly was largest (170.51 ± 30.44 mm2). 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.

Electromyographic biofeedback training in a cerebral palsy patient undergoing pronator teres rerouting and brachioradialis to extensor carpi radialis brevis tendon transfer surgery: A case report.

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.

Comparison of the forearm rotation restriction capacities of four upper-extremity immobilization methods: there is no difference between single and double sugar tong splinting.

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.

Coxa pedis: can calcaneal pronation angle be considered a predictive sign of medial plantar arch overload?

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.

Distal Rotational Metatarsal Osteotomy (DROMO) for the treatment of hallux valgus associated with first metatarsal pronation: Surgical technique and initial results.

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.

Muscle activation while running on the ground compared to artificial turf in males with pronated and supinated feet.

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, η2 =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, η2 =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.

Analysis of anthropometrics and mechanomyography signals as forearm flexion, pronation and supination torque predictors.

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 MMGRMS (r = 0.441), an indication of muscle activation.

Biomechanical assessment of the central band of the interosseous membrane using shear wave elastography: reliability and reproducibility.

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.

Therapeutic Effect of Tendon Bone Setting Technique and Sports Training on Joint Injury.

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.

Hip-Focused Neuromuscular Exercise Provides Immediate Benefits in Foot Pronation and Dynamic Balance: A Sham-Controlled Cross-Over Study.

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.

Partial Distal Biceps Avulsion Results in a Significant Loss of Supination Force.

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.

Intra- and Inter-Examiner Reliability of the Viladot Method in Children.

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 (κp = 0.76; 95% CI, 0.58-0.93; P < .00) and excellent concordance for cavus feet and flat feet (respectively: κp = 0.86; 95% CI, 0.68-1.0; P < .00; and κp = 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: κp = 0.75; 95% CI, 0.57-0.93; P < .00; and κp = 0.69; 95% CI, 0.51-0.87; P < .00) and excellent concordance for flat feet (κp = 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.

Running biomechanics as measured by wearable sensors: effects of speed and surface.

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.

Manufacture and clinical application of the forearm pronation's assistant tableware in the severely burned.

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.

Kinematics of the Feline Antebrachiocarpal Joint from Supination to Pronation.

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.

The role of the interosseous ligament in forearm rotation: A bio-mechanical study.

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.

Foot structural factors and ground reaction force in hallux valgus grades.

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.