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.

Dynamic Supination in Congenital Clubfoot: A Modified Delphi Panel Approach to Standardizing Definitions and Indications for Treatment.

BACKGROUND: Dynamic supination is a well-recognized cause of congenital clubfoot deformity relapse. However, there is no consensus on how to diagnose it and there are varied approaches in its management. This study aims to define dynamic supination and indications for treatment by presenting consensus from an international panel of experts using a modified Delphi panel approach. METHODS: An international panel of 15 pediatric orthopaedic surgeons with clinical and research expertise in childhood foot disorders participated in a modified Delphi panel on dynamic supination in congenital clubfoot. Panelists voted on 51 statements using a 4-point Likert scale on dynamic supination, clinical indications for treatment, operative techniques, and postoperative casting and bracing. All panelists participated in 2 voting rounds with an interim meeting for discussion. Responses were classified as unanimous consensus (100%), consensus (80% or above), near-consensus (70% to 79%), and indeterminate (69% or less). RESULTS: Consensus was achieved for 34 of 51 statements. Panelists agreed dynamic supination is present when the forefoot is supinated during swing phase of gait with initial contact on the lateral border of the foot. There was also agreement that dynamic supination results from muscle imbalance between the tibialis anterior and the peroneus longus and brevis. There was no consensus on observation of hindfoot varus in dynamic supination, operative indications for posterior release of the ankle joint, or incisional approach for tibialis anterior tendon transfer. Reference to the calcaneopedal unit concept, planes of movement, and phases of gait were deemed important factors for consideration when evaluating dynamic supination. CONCLUSIONS: Consensus statements from the Delphi panel can guide diagnosis and treatment of dynamic supination in clubfoot deformity relapse, including clinical decision making regarding preoperative casting, surgical approach, and postoperative immobilization. Near-consensus and indeterminate statements may be used to direct future areas of investigation. LEVEL OF EVIDENCE: Level V.

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.

The biomechanical role of the lacertus fibrosus of the biceps brachii Muscle.

PURPOSE: The lacertus fibrosus (LF) is involved in various surgeries. However, the biomechanical contribution of the LF remains unclear. The aim of this study was to determine the role of the lacertus fibrosus on the elbow and forearm kinematics and on the biceps brachii muscle lever arms. METHODS: This biomechanical study was performed on seven fresh-frozen upper limbs of cadavers. Elbow flexion, forearm supination, and biceps brachii muscle lever arms were analyzed in the intact conditions (I) and after superficial (R) and deep part (R2) of the lacertus fibrosus release, respectively. RESULTS: Elbow flexion shows a significant difference (p < 0.0001) between I, R, R2. Abduction/adduction shows a significant difference between I-R (p < 0.0001) and I-R2 (p < 0.0001). Supination does not show a significant difference in mean maximum amplitude, but between 40 and 70%, there are significant differences. There is a significant mean decrease of lever arm in flexion (28%) and supination (50%) after superficial and deep part of the lacertus fibrosus release. CONCLUSION: The results of this study show that the lacertus fibrosus increases the lever arm during flexion and supination. It limits the flexion and abduction of the elbow and supination of the forearm. Lacertus fibrosus maintains the rhythmicity between the elbow flexion and supination of the forearm. LEVEL OF EVIDENCE: Basic science study, biomechanics.

The effects of forearm position and contraction intensity on cortical and spinal excitability during a submaximal force steadiness task of the elbow flexors.

Elbow flexor force steadiness is less with the forearm pronated (PRO) compared with neutral (NEU) or supinated (SUP) and may relate to neural excitability. Although not tested in a force steadiness paradigm, lower spinal and cortical excitability was observed separately for biceps brachii in PRO, possibly dependent on contractile status at the time of assessment. This study aimed to investigate position-dependent changes in force steadiness as well as spinal and cortical excitability at a variety of contraction intensities. Thirteen males (26 ± 7 yr; means ± SD) performed three blocks (PRO, NEU, and SUP) of 24 brief (~6 s) isometric elbow flexor contractions (5, 10, 25 or 50% of maximal force). During each contraction, transcranial magnetic stimulation or transmastoid stimulation was delivered to elicit a motor-evoked potential (MEP) or cervicomedullary motor-evoked potential (CMEP), respectively. Force steadiness was lower in PRO compared with NEU and SUP (P ≤ 0.001), with no difference between NEU and SUP. Similarly, spinal excitability (CMEP/maximal M wave) was lower in PRO than NEU (25 and 50% maximal force; P ≤ 0.010) and SUP (all force levels; P ≤ 0.004), with no difference between NEU and SUP. Cortical excitability (MEP/CMEP) did not change with forearm position (P = 0.055); however, a priori post hoc testing for position showed excitability was 39.8 ± 38.3% lower for PRO than NEU at 25% maximal force (P = 0.006). The data suggest that contraction intensity influences the effect of forearm position on neural excitability and that reduced spinal and, to a lesser extent, cortical excitability could contribute to lower force steadiness in PRO compared with NEU and SUP.NEW & NOTEWORTHY To address conflicting reports about the effect of forearm position on spinal and cortical excitability of the elbow flexors, we examine the influence of contraction intensity. For the first time, excitability data are considered in a force steadiness context. Motoneuronal excitability is lowest in pronation and this disparity increases with contraction intensity. Cortical excitability exhibits a similar pattern from 5 to 25% of maximal force. Lower corticospinal excitability likely contributes to relatively poor force steadiness in pronation.

Analysis of the crosstalk in mechanomyographic signals along the longitudinal, lateral and transverse axes of elbow flexor muscles during sustained isometric forearm flexion, supination and pronation exercises.

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.

Contraction level, but not force direction or wrist position, affects the spatial distribution of motor unit recruitment in the biceps brachii muscle.

PURPOSE: Different motor units (MUs) in the biceps brachii (BB) muscle have been shown to be preferentially recruited during either elbow flexion or supination. Whether these different units reside within different regions is an open issue. In this study, we tested wheter MUs recruited during submaximal isometric tasks of elbow flexion and supination for two contraction levels and with the wrist fixed at two different angles are spatially localized in different BB portions. METHODS: The MUs' firing instants were extracted by decomposing high-density surface electromyograms (EMG), detected from the BB muscle of 12 subjects with a grid of electrodes (4 rows along the BB longitudinal axis, 16 columns medio-laterally). The firing instants were then used to trigger and average single-differential EMGs. The average rectified value was computed separately for each signal and the maximal value along each column in the grid was retained. The center of mass, defined as the weighted mean of the maximal, average rectified value across columns, was then consdiered to assess the medio-lateral changes in the MU surface representation between conditions. RESULTS: Contraction level, but neither wrist position nor force direction (flexion vs. supination), affected the spatial distribution of BB MUs. In particular, higher forces were associated with the recruitment of BB MUs whose action potentials were represented more medially. CONCLUSION: Although the action potentials of BB MUs were represented locally across the muscle medio-lateral region, dicrimination between elbow flexion or supination seems unlikely from the surface representation of MUs action potentials.

Intra- and intersession reliabilities of the flexor carpi radialis H-reflex while sitting with forearm pronation.

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.

Normalization of Forefoot Supination After Tibialis Anterior Tendon Transfer for Dynamic Clubfoot Recurrence.

BACKGROUND: We aimed to evaluate the effect of tibialis anterior tendon transfer (TATT) on foot motion in children with clubfoot recurrence after initial Ponseti treatment. METHODS: Children with dynamic clubfoot recurrence after initial Ponseti treatment who underwent TATT between 2014 and 2017 were considered for inclusion. Exclusion criteria were neurological disease, split transfer of the tendon, additional bone or joint invasive surgery, and initial treatment abroad. Of 94 children (143 TATT), 36 met the inclusion criteria. Seventeen (47%) of the 36 children with 25 clubfeet and a mean age at the time of surgery of 6.8 years participated in the study. Gait analysis, including the Oxford foot model, was conducted preoperatively and postoperatively. Furthermore, kinematic and kinetic data were compared with those of age-matched healthy children (n=18). RESULTS: Forefoot supination in relation to the hindfoot and tibia was reduced during swing and at initial contact after TATT compared with preoperative values. Forefoot supination in relation to the tibia at initial contact decreased from 12.4 to 5.2 degrees after TATT (control group, 6.0 degrees). The heel showed less dynamic varus and adduction movement after TATT compared with preoperatively. Maximum ankle power was reduced preoperatively and postoperatively compared with controls. Maximum ankle dorsiflexion slightly increased after TATT. CONCLUSIONS: Gait analysis showed normalization of the main components of dynamic clubfoot recurrence after TATT. This joint-sparing surgery efficiently corrects recurrent dynamic deformity. LEVEL OF EVIDENCE: Level II-therapeutic.

Distal radioulnar joint instability: current concepts of treatment.

Distal radioulnar joint (DRUJ) instability is often an underestimated or missed lesion which may entail fatal consequences. The triangular fibrocartilage complex is a biomechanically very important stabilizer of the DRUJ and guarantees unrestricted range of motion of the forearm. To detect DRUJ instability a systematic examination is of uppermost importance. The contralateral healthy arm will be used for comparison during clinical examination. X-rays are required to exclude osseous lesions or deformities. Computed tomography of both wrists in neutral forearm rotation, supination, and pronation may be necessary to verify DRUJ instability in ambiguous situations. Following a systematic clinical examination wrist and DRUJ arthroscopy detects lesions definitely. Tears of the distal radioulnar ligaments which entail DRUJ instability should be repaired preferably anatomically. Ulnar-sided ligament ruptures which cause instability are detected more often than radial-sided ones. Osseous ligament avulsions are mostly refixated osteosynthetically. Ligamentous tears of the distal radioulnar ligaments may be reconstructed using anchor suture or transosseous refixation. Secondary procedures such as tendon transplants are necessary for anatomical reconstruction in cases of unrepairable ligament tears.

Evaluation of the supinator muscle and deep branch of the radial nerve: impact on nerve compression.

PURPOSE: The aim of this study was to investigate the superficial head of supinator muscle (SM) and deep branch of the radial nerve (DBRN) course in SM to see whether the texture characteristics of the superficial head of SM might have a potential compressive effect on the nerve. MATERIALS AND METHODS: Elbow and proximal forearm region of 20 preserved cadavers (n 40, 12 M, 8 F) were dissected in order to measure total and part of DBRN lengths between some reference points. The texture characteristics of both the proximal (where DBRN enters SM) and distal arcade (where DBRN exits SM) of the superficial head of SM were evaluated based on its structure's being muscular, musculotendinous, tendinous, or membranous. RESULTS: The total length of DBRN between sexes without taking side (L/R) into consideration (P = 0.030) and left radiocapitellar joint (RCJ)-arcade of Frohse (AF) length between sexes (P = 0.050) were statistically significant. There was a gradual increase in caliber getting more flattened in every consecutive level which was statistically significant when every two consecutive levels were compared. When compared according to the texture type, there were also significant differences. CONCLUSIONS: Flattening of DBRN in the supinator canal suggests a chronic compression on the nerve. Differences in the texture of the superficial head of the supinator might facilitate this compression. An understanding of the anatomy and nerve topography is of utmost importance in the accurate diagnosis and effective management of peripheral nerve compression.

In vivo changes in length of elbow collateral ligaments during pronation and supination on an outstretched arm.

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.

Doctor, when can I drive? - Range of functional ankle motion during driving.

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.

Diagnostic capability of dynamic ultrasound evaluation of supination-external rotation ankle injuries: a cadaveric study.

BACKGROUND: Ankle syndesmosis injuries are common and range in severity from subclinical to grossly unstable. Definitive diagnosis of these injuries can be made with plain film radiographs, but are often missed when severity or image quality is low. Computed tomography (CT) and magnetic resonance imaging (MRI) can provide definitive diagnosis, but are costly and introduce the patient to radiation when CT is used. Ultrasonography may circumvent many of these disadvantages by being inexpensive, efficient, and able to detect injuries without radiation exposure. The purpose of this study was to evaluate the ability of ultrasonography to detect early stage supination-external rotation (SER) ankle syndesmosis injuries with a dynamic external rotational stress test. METHODS: Nine, all male, fresh frozen specimens were secured to an ankle rig and stress tested to 10 Nm of external rotational torque with ultrasonography at the tibiofibular clear space. The ankles were subjected to syndesmosis ligament sectioning and repeat stress measurements of the tibiofibular clear space at peak torque. Stress tests and measurements were repeated three times and averaged and analyzed using a repeated one-way analysis of variance (ANOVA). There were six ankle injury states examined including: Intact State, 75% of AITFL Cut, 100% of AITFL Cut, Fibula FX - Cut 8 cm proximal, 75% PITFL Cut, and 100% PITFL Cut. RESULTS: Dynamic external rotation stress evaluation using ultrasonography was able to detect a significant difference between the uninjured ankle with a tibiofibular clear space of 4.5 mm and the stage 1 complete injured ankle with a clear space of 6.0 mm (P < .02). Additionally, this method was able to detect significant differences between the uninjured ankle and the stage 2-4 injury states. CONCLUSION: Dynamic external rotational stress evaluation using ultrasonography was able to detect stage 1 Lauge-Hansen SER injuries with statistical significance and corroborates criteria for diagnosing a syndesmosis injury at ≥6.0 mm of tibiofibular clear space widening.

The Effect of Distal Radius Fracture Location on Distal Radioulnar Joint Stability: A Cadaveric Study.

PURPOSE: To investigate whether the location of distal radius osteotomy/shortening relative to the radial insertion of the distal interosseous membrane (DIOM) is correlated with distal radioulnar joint (DRUJ) instability. We hypothesized that distal radius osteotomy and shortening proximal to the DIOM insertion would result in increased DRUJ instability because of induced laxity in the DIOM. METHODS: Osteotomies of the distal radius were performed proximal and distal to the DIOM insertion in 14 fresh-frozen cadaveric specimens. Using a volar plate, 5 conditions were tested: anatomical radius alignment; 2- and 4-mm shortening at the proximal osteotomy site; and 2- and 4-mm shortening at the distal osteotomy site. Basilar ulnar styloid osteotomy was performed to simulate triangular fibrocartilage complex (TFCC) detachment-specimens were tested with the ulnar styloid detached and the ulnar styloid fixed (to restore normal anatomy). The DRUJ stability was quantified using dorsal-volar displacement of the radius in response to 20 N of force using a force-displacement probe in neutral, pronation, and supination. Posttesting specimen dissections assessed DIOM and distal oblique bundle (DOB) anatomy. The DRUJ stability in each experimental condition was compared with a multifactor repeated measures analysis of variance with the specimen treated as the repeated factor. RESULTS: There were no significant differences in dorsal-volar translation of the radius (ie, DRUJ stability) between radial osteotomy/shortening proximal and distal to the DIOM insertion, regardless of forearm rotational position or magnitude of shortening. Five (36%) of the 14 specimens had a DOB present. There was a significant increase in DRUJ instability in the setting of TFCC detachment (via basilar ulnar styloid osteotomy). CONCLUSIONS: No difference in DRUJ stability was observed between distal radius osteotomy/shortening proximal and distal to the DIOM radial insertion, regardless of forearm rotation, magnitude of shortening, and/or TFCC detachment. CLINICAL RELEVANCE: Distal radius osteotomy and shortening did not affect DRUJ stability regardless of location relative to the DIOM insertion.

Supination torque following single- versus double-incision repair of acute distal biceps tendon ruptures.

BACKGROUND: Compared with single-incision (SI) distal biceps repair, double-incision (DI) repair has been described as permitting a more anatomic repair. We hypothesized that DI repair would result in greater terminal supination torque compared with SI repair for acute distal biceps ruptures. METHODS: Patients were included if they sustained an isolated, acute distal biceps rupture repaired between January 2012 and December 2017. Isometric forearm supination torque in 4 positions was measured using a validated uniaxial torque-testing device. Testing took place at least 12 months from surgery. The primary outcome was supination torque in the 60° supinated position. Secondary outcomes included supination torque in other forearm positions and functional outcome scores. RESULTS: The study included 37 patients: 15 underwent repair with the DI technique and 22 with the SI technique. The mean age was 47.3 years, the median follow-up time was 28.1 months, and demographic data were similar between cohorts. Mean supination torque, relative to the unaffected side, was 61% (95% confidence interval, 45%-77%) for DI repair vs. 80% (95% confidence interval, 69%-92%) for SI repair in the 60° supinated position (P = .036). In a multivariable linear regression model controlling for arm dominance, age, follow-up time, and workers' compensation status; SI repair was associated with greater mean supination torque than DI repair by 20% (P = .015). CONCLUSIONS: Contrary to our hypothesis, we found a 20% mean improvement in terminal supination torque for acute distal biceps ruptures repaired with the SI technique compared with the DI technique. This finding may have clinical significance for the more discerning, high-demand patient.

The validity and reliability of DrGoniometer, a smartphone application, for measuring forearm supination.

STUDY DESIGN: Clinical measurement (reliability and validity) study. INTRODUCTION: Forearm supination is important in many daily activities and is thus measured by therapists and researchers usually with a universal goniometer. DrGoniometer, a SmartPhone application, has been validated for other joint angles in the body. PURPOSE OF THE STUDY: To establish the reliability and validity of DrGoniometer (CDM S.r.L, Cagliari, Italy) for measuring forearm supination in healthy populations and those with forearm fractures. METHODS: Participants had sustained a distal radius fracture that was treated non-surgically. Forearm supination of the participant's fractured (n = 30) and healthy forearm (n = 30) was measured using DrGoniometer and the universal goniometer by two assessors. The assessors were blinded to each other's measurements and their own previous measurements. Reliability was established by calculating Intra-class Correlation Coefficients, standard error of measurement and minimal detectable change. The validity of DrGoniometer was established against the universal goniometer using Pearson's correlation co-efficient. RESULTS: Intra-rater reliability of both DrGoniometer and the universal goniometer was high for both fractured and healthy forearms (ICCs ranged from 0.74-0.88). Inter-rater reliability of both DrGoniometer and the universal goniometer was also high in the fractured forearm group (0.76 and 0.72 respectively), but low in the healthy forearm group (0.34 and 0.42 respectively). Correlation between the tools was excellent across the fractured and healthy forearm groups (0.94 and 0.93 respectively). DISCUSSION: Both goniometers demonstrated good-to-excellent intrarater and iner-rater reliability except in the healthy forearm group where both goniometers demonstrated poor inter-rater reliability which could be due to assessor instructions. The speed the photo can be taken and the digital record obtained are valuable aspects of DrGoniometer. CONCLUSION: DrGoniometer is a valid, alternate tool for measuring forearm supination.

Self-measured wrist range of motion by wrist-injured and wrist-healthy study participants using a built-in iPhone feature as compared with a universal goniometer.

STUDY DESIGN: Cross-sectional cohort. INTRODUCTION: Smartphone gyroscope and goniometer applications have been shown to be a reliable way to measure wrist ROM when used by researchers or trained staff. If wrist-injured patients could reliably measure their own ROM, rehabilitation efforts could be more effectively tailored. PURPOSE OF THE STUDY: To assess agreement of self-measured ROM by wrist-injured and wrist-healthy study participants using a built-in iPhone 5 level feature as compared to researcher-measured ROM using a universal goniometer (UG). METHODS: Thirty wrist-healthy and 30 wrist-injured subjects self-measured wrist flexion, extension, supination, and pronation ROM using the built-in preinstalled digital level feature on an iPhone 5. Simultaneously a researcher measured ROM with a UG. RESULTS: Average absolute deviation between the self-measured iPhone 5 level feature and researcher-measured UG ROM was less than 2° for all 4 movements individually and combined was found to be 1.6° for both populations. Intraclass correlation coefficient showed high correlation with values over 0.94 and Bland-Altman plots showed very strong agreement. There was no statistical difference in the ability of wrist-injured and healthy patients to self-measure wrist ROM. DISCUSSION: Both populations showed very high agreement between their self-measured ROM using the built-in level feature on an iPhone 5 and the researcher-measured ROM using the UG. Both populations were able to use the iPhone self-measurement equally well and the injury status of the subject did not affect the agreement results. CONCLUSION: Wrist-healthy and wrist-injured subjects were able to reliably and independently measure ROM using a smartphone level feature.

Effect of salient points in movements on the constraints in bimanual coordination.

The relative-salience hypothesis has been proposed as a possible explanation for the stability of bimanual coordination. This explanation proceeds from a psychological viewpoint and is based on the following tenets: (1) cyclic joint motions involving two movements are conceived of as a unified event, (2) if a "single" point in each movement is seen as the most salient, the salient points of the two movements prefer to go together, and (3) in other cases, a unified event will be constrained by movement direction. In this investigation, we examined whether the relative-salience hypothesis could predict the type of constraint (i.e., action coupling vs movement direction) for various bimanual coordination movements. Participants performed six different joint movements in synchrony with metronome beats. Both index finger flexion/extension and forearm pronation/supination had a "single" salient point (JMsingleSP), the others had "two" salient points (JMtwoSP). Then, we applied the relative-salience hypothesis to four bimanual coordinations. The coupling of simultaneous forearm pronation was more stable than alternate pronation. Similarly, the coupling of finger flexion and forearm pronation was more stable than that of finger flexion and forearm supination. For the coordination of radial flexion/ulnar flexion and index finger flexion/extension as well as forearm pronation/supination and radial flexion/ulnar flexion, symmetric movements were more stable than asymmetric movements. The results indicated that the stability of bimanual coordination was predominantly constrained by coupling of salient points when using two JMsingleSP and it was predominantly constrained by movement direction when coordinating JMsingleSP and JMtwoSP. Thus, the relative-salience hypothesis was supported.

Morphological characteristics of the posterior malleolar fragment according to ankle fracture patterns: a computed tomography-based study.

BACKGROUND: The posterior malleolar fragment (PMF) of an ankle fracture can have various shapes depending on the injury mechanism. The purpose of this study was to evaluate the morphological characteristics of the PMF according to the ankle fracture pattern described in the Lauge-Hansen classification by using computed tomography (CT) images. METHODS: We retrospectively analyzed CT data of 107 patients (107 ankles) who underwent surgery for trimalleolar fracture from January 2012 to December 2014. The patients were divided into two groups: 76 ankles in the supination-external rotation (SER) stage IV group and 31 ankles in the pronation-external rotation (PER) stage IV group. The PMF type of the two groups was assessed using the Haraguchi and Jan Bartonicek classification. The cross angle (α), fragment length ratio (FLR), fragment area ratio (FAR), sagittal angle (θ), and fragment height (FH) were measured to assess the morphological characteristics of the PMF. RESULTS: The PMF in the SER group mainly had a posterolateral shape, whereas that in the PER group mainly had a posteromedial two-part shape or a large posterolateral triangular shape (P = 0.02). The average cross angle was not significantly different between the two groups (SER group = 19.4°, PER group = 17.6°). The mean FLR and FH were significantly larger in the PER group than in the SER group (P = 0.024, P = 0.006). The mean fragment sagittal angle in the PER group was significantly smaller than that in the SER group (P = 0.017). CONCLUSIONS: With regard to the articular involvement, volume, and vertical nature, the SER-type fracture tends to have a smaller fragment due to the rotational force, whereas the PER-type fracture tends to have a larger fragment due to the combination of rotational and axial forces.