Frontal Plane Correction of Hallux Valgus Deformity With a Minimally Invasive Third Generation Tecnique: Short-Term Radiographic Outcomes of a Prospective Case Series

A number of minimally invasive osteotomies have been described for the repair of hallux abducto valgus (HAV) deformities. However, there are no known published studies that evaluate the effects of minimally invasive surgery techniques on the reduction of frontal plane rotation in patients with HAV. The purpose of this study was to assess correction in the transverse and frontal planes in patients undergoing surgical repair of HAV deformity utilizing a modified percutaneous technique. One hundred and five feet in 105 patients with HAV deformity were treated with a third generation minimally invasive technique using a first metatarsal osteotomy that allowed for frontal plane correction in conjunction with an Akin osteotomy. The minimum follow-up time was 12 months. Preoperative and postoperative anteroposterior weightbearing x-ray images were assessed and four measurements were evaluated: hallux abductus angle (HAA), intermetatarsal angle (IMA), tibial sesamoid position and frontal plane rotation of the first metatarsal. There were statistically significant differences for each of the assessments between the preoperative and postoperative radiographs (p < .001). There was a mean reduction in the HAA of 23.5° ± 9.6°, in the IMA, 7.0° ± 3.5°, in the tibial sesamoid position, 2.6 ± 1.3, and an improvement in the assessment of first metatarsal pronation (1.4 ± 0.9). The overall complication rate was 18.1%, with 5.7% of the feet requiring reoperation. The minimally invasive procedure employed by the authors demonstrated suitable outcomes in reducing deformity in both the transverse and frontal planes.

Validity, reliability and responsiveness of a goniometer watch to measure pure forearm rotation

Introduction

Innovative instruments have been designed to assess forearm rotation, an anatomically challenging motion to measure. This study assessed the concurrent validity, interrater reliability and responsiveness of a novel goniometer watch (GoWatch) to measure pure forearm rotation. The modified finger goniometer (MFG) was the criterion reference.

Methods

Forty participants with restricted forearm rotation were recruited. Two raters measured supination and pronation using the GoWatch and MFG before and after a hand therapy session. Repeated-measures ANOVA assessed for systematic bias with an apriori residual error of 5° deemed as acceptable. Secondary analysis used intraclass coefficients (ICCs) to categorise interrater reliability. Responsiveness of the GoWatch was calculated using Cohen's d.

Results

The GoWatch demonstrated acceptable agreement with the MFG with a mean difference for supination 1.19° and pronation 0.20°. Interrater reliability was also within acceptable limits with a mean difference GoWatch supination 4.43° and pronation 2.23°. Interrater reliability for GoWatch supination and pronation were categorized as excellent (ICC = 0.94) and good (ICC = 0.85) respectively. Systematic bias was observed in the instrument by rater interaction with rater two consistently underestimating GoWatch measures (p<.05). GoWatch supination showed small to medium responsiveness (Rater 1: d = 0.14; Rater 2: d = 0.29) and pronation very small to medium responsiveness (Rater 1: d = 0.29; Rater 2: d = 0.05).

Conclusion

The GoWatch is a viable and user-friendly alternative to measure forearm rotation with demonstrable validity, interrater reliability and responsiveness. Further research is required to ensure systematic bias is not endemic when used across multiple raters.

Hallux Valgus: The Influence of Intersesamoid Crista's Osteoarthritis on Frontal Plane Pronation

A frontal plane metatarsal rotational (pronation) has been documented in a high percentage of hallux valgus patients. Pathoanatomical concepts leading to pronation are still debated. Nevertheless, there is no consensus on how to measure this component of the deformity. The aim of the present study was to find potential associations between sesamoid's crista osteoarthritis and the frontal plane deformity in HV cases. Our study showed a moderate correlation between the crista's OA and the intermetatarsal angle (IMA), the hallux valgus angle (HVA) and the alpha angle. In severe hallux vulgus deformed specimens, with an eroded intersesamoid crista, frontal plane pronation was not as prevalent nor severe as in those without osteoarthritic degeneration. Severe hallux valgus cases with a completely eroded crista, showed lower pronation, and higher IMA, when compared to specimens with a preserved anatomy. This brings to light the intersesamoid crista's unique function in retaining the IMA. Understanding the role the frontal plane plays in hallux valgus' biomechanics and in its radiographic appearance is vital to change the current paradigm.

A Muscle Energy Techniques-Based Physiotherapeutic Intervention Protocol for Managing Nightstick Fracture: A Case Report

Distal ulna and radius fractures are the most frequent upper extremity fractures seen in emergency rooms. The axis of rotation for forearm pronation and supination runs through the radial head (proximal) and the ulnar fovea (distal). Throughout pronation and supination, the radius can rotate relative to the ulna, thanks to the way its head articulates with it. The ulna remains relatively stable during these movements. However, in cases of fractures of these bones, surgery to repair the radius is usually the best course of action for a distal ulna fracture. Most distal ulna fractures heal successfully with only conservative treatment once the radius is stabilized. To achieve the best results, medical personnel must take into account patient characteristics including age, level of activity, and aspirations. The majority of distal ulna injuries do not require surgery, but there are several circumstances where it is necessary. In therapeutic practice, muscle energy techniques (METs) are comparatively painless methods for restoring a restricted spectrum of motion. Malunion, reduced grasp, and other significant problems might result from a lack of understanding of this illness. The 48-year-old patient in the present study was reported to have sustained injuries to his left forearm in a road traffic accident (RTA) as he fell from his bike and slid during a traffic collision. X-ray imaging of the left forearm revealed an isolated ulnar shaft fracture. METs, isometric contractions, and active concentric and eccentric movements were all part of the physiotherapy intervention protocol to produce an active range of motion in the upper extremity. In this particular case, the specified physiotherapy management was found to be effective.

Prevalence of adverse events in pronated intubated adult COVID-19 patients: A systematic review with meta-analysis

AIM

To present the pooled estimated prevalence of adverse events in pronated intubated adult COVID-19 patients.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

This study used the Cochrane Library, CINAHL, Embase, LILACS, Livivo, PubMed, Scopus, and Web of Science databases as data sources.

METHODS

The studies were meta-analysed using JAMOVI 1.6.15 software. A random-effects model was used to identify the global prevalence of adverse events, confidence intervals and the heterogeneity data. Risk of bias was assessed using the Joanna Briggs Institute tool, and the certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Of the 7904 studies identified, 169 were included for full reading, and 10 were included in the review. The most prevalent adverse events were pressure injuries (59%), haemodynamic instability (23%), death (17%) and device loss or traction (9%).

CONCLUSION

The most prevalent adverse events in mechanically ventilated pronated patients with COVID-19 are pressure injuries, presence of haemodynamic instability, death and device loss or traction.

IMPLICATIONS FOR THE PATIENT CARE

The evidence identified in this review can help improve the quality and safety of patient care by helping to design care protocols to avoid the development of adverse events that can cause permanent sequelae in these patients.

IMPACT

This systematic review addressed the adverse events related to prone position in intubated adult COVID-19 patients. We identified that the most prevalent adverse events in these patients were pressure injuries, haemodynamic instability, device loss or traction and death. The results of this review may influence the clinical practice of nurses who work in intensive care units and, consequently, the nursing care provided not only to COVID-19 patients but for all intubated patients due to other reasons in intensive care units.

REPORTING METHOD

This systematic review adhered to the PRISMA reporting guideline.

PATIENT OR PUBLIC CONTRIBUTION

As this is a systematic review, we analysed data from primary studies conducted by many researchers. Thus, there was no patient or public contribution in this review.

Prone positioning during CPAP therapy in SARS-CoV-2 pneumonia: a concise clinical review

During the COVID-19 pandemic, the number of patients with hypoxemic acute respiratory failure (ARF) due to SARS-CoV-2 pneumonia threatened to overwhelm intensive care units. To reduce the need for invasive mechanical ventilation (IMV), clinicians tried noninvasive strategies to manage ARF, including the use of awake prone positioning (PP) with continuous positive airway pressure (CPAP). In this article, we review the patho-physiologic rationale, clinical effectiveness and practical issues of the use of PP during CPAP in non-intubated, spontaneously breathing patients affected by SARS-CoV-2 pneumonia with ARF. Use of PP during CPAP appears to be safe and feasible and may have a lower rate of adverse events compared to IMV. A better response to PP is observed among patients in early phases of acute respiratory distress syndrome. While PP during CPAP may improve oxygenation, the impact on the need for intubation and mortality remains unclear. It is possible to speculate on the role of PP during CPAP in terms of improvement of ventilation mechanics and reduction of strain stress.

Impact of Sesamoid Coverage on Clinical Foot Function Following Fourth-Generation Percutaneous Hallux Valgus Surgery

Background

The impact of pronation and sesamoid coverage on clinical outcomes following percutaneous hallux valgus surgery are not currently known. The aim of this study was to investigate if sesamoid coverage was associated with worse clinical outcomes at 12-month follow-up following percutaneous hallux valgus surgery.

Methods

Retrospective comparative observational study of clinical and radiographic outcomes based on a previously published prospective dataset. Patients were stratified into 3 cohorts based on the degree of sesamoid coverage (normal, mild, or moderate) on 12-month weightbearing radiographs following fourth-generation percutaneous hallux valgus surgery. Primary outcome was a validated patient-reported outcome measure (PROM), the Manchester-Oxford Foot Questionnaire (MOXFQ). Secondary outcomes included Euroqol-5D, VAS Pain, and radiographic deformity correction.

Results

Forty-seven feet underwent primary fourth-generation HV surgery and were stratified into 3 cohorts. There were 19, 16, and 12 feet in the normal, mild, and moderate cohorts respectively. There was no significant difference in either pre- or postoperative foot function (all MOXFQ domains, P > .05) or health-related quality of life (EQ-5D Index or VAS, P > .05). The MOXFQ Index preoperatively was as follows: normal cohort, 56.1 ± 26.9; mild cohort, 54.1 ± 17.9; and severe cohort, 49.6 ± 23.8; and postoperatively was as follows: normal cohort, 15.6 ± 21.5; mild cohort, 11.4 ± 15.5; and severe cohort, 11.4 ± 13.6 (P = .737-.908). There was significantly worse hallux valgus angle (HVA) and intermetatarsal angle (IMA) between the cohorts (P < .01). Although HVA and IMA were corrected to normal parameters following surgery in all cohorts, there was a significantly worse postoperative HVA in the moderate sesamoid coverage (5.3 ± 3.9 vs 7.9 ± 5.3 vs 11.4 ± 3.7, P < .01); however, IMA was not significantly different (3.4 ± 2.2 vs 4.1 ± 2.7 vs 5.2 ± 2.9, P = .168).

Conclusion

This study found that cases where the sesamoids were not reduced had a poorer correction and had worse preoperative deformity. Clinical outcomes and foot function following fourth-generation percutaneous hallux valgus surgery were not affected by sesamoid coverage at the 12-month follow-up. The long-term implications in the difference in radiographic deformity between the 3 cohorts are not known, and further work should explore the relationship of first ray pronation and sesamoid position, particularly with regard to recurrence.

Level of evidence

Level III, retrospective comparative study of prospectively collected data.

Thumb pronation efficacy of Camitz tendon transfer with insertion on the ulnar capsule of the metacarpophalangeal joint: a cadaver study

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.    .

A Short-Term Evaluation of Foot Pronation Tendency in Healthy Recreational Runners

Running is a highly physical activity, and it is related to injuries when there is an excessive pronation of the foot. This study evaluates, from a sample group of healthy recreational runners, if the foot tends to pronate after a period of running activity and when, with respect to a period of running compared to walking, evaluated during several phases: after 30, 45, and 60 min. This quasi-experimental study has been carried out on a total of 36 healthy recreational subjects. The subjects were evaluated during two different activities: running activity for a period of an hour with respect to normal walking activity. The main outcome measures were the foot posture index (FPI) and the navicular drop test (NDT), which were evaluated at p1 (the screening day), after 30 min of activity (p2), after 45 min of activity (p3), and finally after 60 min (p4) during running or walking activity. The analysis showed significant differences for the FPI and NDT variables in both groups and on both feet, comparing p1 and p4. These changes showed a significant relationship comparing p1 and p3 for the FPI variable, and for the NDT variable (p < 0.001) of the left foot and, with respect to the right foot, significance was shown to the FPI comparing the p1 and p2. A significant difference was found in the tendency to pronate the foot after a period of running compared to the same period of walking after 60 min of activity. Running produced an excessive pronation of the foot after 45 min of activity, evaluated with the FPI for both feet.

A Deep Learning Approach for Automatic and Objective Grading of the Motor Impairment Severity in Parkinson's Disease for Use in Tele-Assessments

Wearable sensors provide a tool for at-home monitoring of motor impairment progression in neurological conditions such as Parkinson's disease (PD). This study examined the ability of deep learning approaches to grade the motor impairment severity in a modified version of the Movement Disorders Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) using low-cost wearable sensors. We hypothesized that expanding training datasets with motion data from healthy older adults (HOAs) and initializing classifiers with weights learned from unsupervised pre-training would lead to an improvement in performance when classifying lower vs. higher motor impairment relative to a baseline deep learning model (XceptionTime). This study evaluated the change in classification performance after using expanded training datasets with HOAs and transferring weights from unsupervised pre-training compared to a baseline deep learning model (XceptionTime) using both upper extremity (finger tapping, hand movements, and pronation-supination movements of the hands) and lower extremity (toe tapping and leg agility) tasks consistent with the MDS-UPDRS. Overall, we found a 12.2% improvement in accuracy after expanding the training dataset and pre-training using max-vote inference on hand movement tasks. Moreover, we found that the classification performance improves for every task except toe tapping after the addition of HOA training data. These findings suggest that learning from HOA motion data can implicitly improve the representations of PD motion data for the purposes of motor impairment classification. Further, our results suggest that unsupervised pre-training can improve the performance of motor impairment classifiers without any additional annotated PD data, which may provide a viable solution for a widely deployable telemedicine solution.

Ultrasonographic examination of the safe zone for medial needle approach towards the median-innervated flexor digitorum profundus muscle: Effect of changes in position of the forearm

The flexor digitorum profundus (FDP) is a forearm flexor muscle. Certain cases require the needle to be inserted accurately and safely into the deep, lateral portion of the FDP, which is innervated by the anterior interosseous nerve. In this study, we compared 2 techniques for approaching the median-innervated FDP (MFDP) medially, each according to the position of the forearm, supinated or pronated. The forearms of healthy volunteers without any musculoskeletal problems of the upper extremities were examined. Using high-resolution ultrasonography, the medial aspects of the forearms were scanned with elbows flexed at 90°. Using the images obtained, several parameters for distance and angle were measured in 2 different positions: forearm-supinated and forearm-pronated. Thirty-seven forearms from the volunteers were subject to examination. The angle α, which is the valid angle of insertion when approaching with the needle towards the deeply located MFDP, slightly increased from 22.89° to 23.41° when the forearm was pronated from the supinated position; however, this increase was not statistically significant. In contrast, the angle β, which is the safe angle of insertion when approaching with the needle towards the MFDP without contacting the ulnar nerve, was significantly increased from 41.40° to 46.80° upon forearm pronation. Because the safe angle of insertion of the needle medially into the MFDP increases with forearm pronation, the forearm-pronated position is recommended, instead of the forearm-supinated position, when inserting a needle into the MFDP in the medial aspect of the forearm.

Pilot Study: The Relationship between Foot Posture and Movement Quality in Non-Professional Male Football Players

(1) Background: This study focusses on establishing the relationship between quality of movement (based on the functional movement screen, or FMS) and foot posture (based on the foot posture index, or FPI-6). We hypothesised that a poor FMS test score may be derived from the foot position in the space measured by FPI-6. (2) Methods: a quasi-experimental and cross-sectional study was designed to analyse foot posture in 30 healthy football players, using the foot posture index and the functional movement screen. (3) Results: No significant relationships were found between movement quality and foot posture. Poor movement quality is present in more than half of all foot positions, supination, pronation, and neutral. Good quality seems to be more associated with a neutral foot position (23.3%) and supinated (16.6%) than a pronated foot position (6.6%). (4) Conclusions: this study found no relationship between the two tests; therefore, we cannot demonstrate that foot posture is relevant in the quality of the movement of the football players studied.

Republication of "Proximal Rotational Metatarsal Osteotomy for Hallux Valgus (PROMO): Short-term Prospective Case Series With a Novel Technique and Topic Review"

Background

Hallux valgus deformity consists of a lateral deviation of the great toe, metatarsus varus, and pronation of the first metatarsal. Most osteotomies only correct varus, but not the pronation of the metatarsal. Persistent postoperative pronation has been shown to increase deformity recurrence and have worse functional outcomes. The proximal rotational metatarsal osteotomy (PROMO) technique reliably corrects pronation and varus through a stable osteotomy, avoiding fusing any healthy joints. The objective of this research is to show a prospective series of the PROMO technique.

Methods

Twenty-five patients (30 feet) were operated with the PROMO technique. The sample included 22 women and 3 men, average age 46 years (range 22-59), for a mean prospective follow-up of 1 year (range 9-14 months). Inclusion criteria included symptomatic hallux valgus deformities, absence of severe joint arthritis, or inflammatory arthropathies, with a metatarsal malrotation of 10 degrees or more, with no tarsometatarsal subluxation or arthritis on the anteroposterior or lateral foot radiograph views. The mean preoperative and postoperative Lower Extremity Functional Scale (LEFS) score, metatarsophalangeal angle, intermetatarsal angle, metatarsal malrotation, complications, satisfaction, and recurrence were recorded.

Results

The mean preoperative and postoperative LEFS scores were 56 and 73. The median pre-/postoperative metatarsophalangeal angle was 32.5/4 degrees and the intermetatarsal angle 15.5/5 degrees. The metatarsal rotation was satisfactorily corrected in 24 of 25 patients. An Akin osteotomy was needed in 27 of 30 feet. All patients were satisfied with the surgery, and no recurrence or complications were found.

Conclusions

PROMO is a reliable technique, with good short-term results in terms of angular correction, satisfaction, and recurrence. Long-term studies are needed to determine if a lower hallux recurrence rate occurs with the correction of metatarsal rotation in comparison with conventional osteotomies.

Level of evidence

IV, prospective case series.

First Metatarsal Rotation After Scarf Osteotomy for Hallux Valgus

BACKGROUND

Recurrence after surgical correction of hallux valgus may be related to coronal rotation of the first metatarsal. The scarf osteotomy is a commonly used procedure for correcting hallux valgus but has limited ability to correct rotation. Using weight-bearing computed tomography (WBCT), we aimed to measure the coronal rotation of the first metatarsal before and after a scarf osteotomy, and correlate these to clinical outcome scores.

METHODS

We retrospectively analyzed 16 feet (15 patients) who had a WBCT before and after scarf osteotomy for hallux valgus correction. On both scans, hallux valgus angle (HVA), intermetatarsal angle (IMA), and anteroposterior/lateral talus-first metatarsal angle were measured using digitally reconstructed radiographs. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle, and sesamoid position were measured on standardized coronal WBCT slices. Preoperative and postoperative (12 mo) clinical outcome scores (Manchester Oxford Foot Questionnaire and Visual Analogue Scores) were captured.

RESULTS

Mean HVA was 28.6 ± 10.1° preoperatively and 12.1 ± 7.7° postoperatively (P < .001). Mean IMA was 13.7 ± 3.8° preoperatively and 7.5 ± 3.0° postoperatively (P < .001). Before and after surgery, there were no significant differences in MPA (11.4 ± 7.7 and 11.4 ± 9.9°, respectively; P = .75) or alpha angle (10.9 ± 8.0 and 10.7 ± 13.1°, respectively; P = .83). There were significant improvements in sesamoid rotation angle (SRA) (26.4 ± 10.2 and 15.7 ± 10.2°, respectively; P = .03) and sesamoid position (1.4 ± 1.0 and 0.6 ± 0.6, respectively; P = .04) after a scarf osteotomy. There were significant improvements in all outcome scores after surgery. Poorer outcome scores correlated with greater postoperative MPA and alpha angles (r = .76 (P = .02) and .67 (P = .03), respectively).

CONCLUSION

A scarf osteotomy does not correct first metatarsal coronal rotation, and worse outcomes are linked to greater postoperative metatarsal rotation. Rotation of the metatarsal needs to be measured and considered when planning hallux valgus surgery. Further work was needed to compare postoperative outcomes with rotational osteotomies and modified Lapidus procedures when addressing rotation.Level of Evidence: 4.

Effect of COVID-19 on the incidence of postintubation laryngeal lesions

Background

Critically ill patients intubated in the intensive care unit experience prolonged intubation leading to increased frequency of laryngeal injuries. This study aimed to demonstrate a suspected increase in vocal fold injury in patients who were intubated with COVID-19 as compared with patients intubated for other reasons.

Methods

A retrospective review of medical records was performed to identify patients examined using flexible endoscopic evaluation of swallowing exams. The study included 25 patients with COVID-19 and 27 without COVID-19 at Baylor Scott & White Medical Center in Temple, Texas. Various injuries were evaluated, ranging from granulation tissue to vocal cord paralysis. Severe lesions were those causing clinically significant airway obstruction or requiring operative intervention. The incidence of laryngeal injury in patients intubated for COVID-19 was then compared with that of patients intubated for other reasons.

Results

The increased presence of severe injury in COVID-positive patients appeared clinically significant but was not statistically significant (P = 0.06). Interestingly, patients who received pronation therapy had 4.6 times the odds of more severe injury compared with patients who did not (P = 0.009).

Conclusion

Lower thresholds for performing flexible laryngoscopy on postintubated patients who are proned may allow for earlier intervention and reduce morbidity in an already at-risk population.

Brain Connectivity Analysis in Distinct Footwear Conditions during Infinity Walk Using fNIRS

Gait and balance are an intricate interplay between the brain, nervous system, sensory organs, and musculoskeletal system. They are greatly influenced by the type of footwear, walking patterns, and surface. This exploratory study examines the effects of the Infinity Walk, pronation, and footwear conditions on brain effective connectivity patterns. A continuous-wave functional near-infrared spectroscopy device collected data from five healthy participants. A highly computationally efficient connectivity model based on the Grange causal relationship between the channels was applied to data to find the effective relationship between inter- and intra-hemispheric brain connectivity. Brain regions of interest (ROI) were less connected during the barefoot condition than during other complex walks. Conversely, the highest interconnectedness between ROI was observed while wearing flat insoles and medially wedged sandals, which is a relatively difficult type of footwear to walk in. No statistically significant (p-value <0.05) effect on connectivity patterns was observed during the corrected pronated posture. The regions designated as motoric, sensorimotor, and temporal became increasingly connected with difficult walking patterns and footwear conditions. The Infinity Walk causes effective bidirectional connections between ROI across all conditions and both hemispheres. Due to its repetitive pattern, the Infinity Walk is a good test method, particularly for neuro-rehabilitation and motoric learning experiments.

Pilot Study: Effect of Morton's Extension on the Subtalar Joint Forces in Subjects with Excessive Foot Pronation

This study focuses on the assessment of the mechanical effect produced by Morton's extension as an orthopedic intervention in patients with bilateral foot pronation posture, through a variation in hindfoot and forefoot prone-supinator forces during the stance phase of gait. A quasi-experimental and transversal research was designed comparing three conditions: barefoot (A); wearing footwear with a 3 mm EVA flat insole (B); and wearing a 3 mm EVA flat insole with a 3 mm thick Morton's extension (C), with respect to the force or time relational to the maximum time of supination or pronation of the subtalar joint (STJ) using a Bertec force plate. Morton's extension did not show significant differences in the moment during the gait phase in which the maximum pronation force of the STJ is produced, nor in the magnitude of the force, although it decreased. The maximum force of supination increased significantly and was advanced in time. The use of Morton's extension seems to decrease the maximum force of pronation and increase supination of the subtalar joint. As such, it could be used to improve the biomechanical effects of foot orthoses to control excessive pronation.

Anatomy of the distal radioulnar ligament in cats

OBJECTIVES

The aim of this study was to describe the anatomy of the distal radioulnar ligament in the cat, using gross and histological sections from cadaveric feline carpi.

METHODS

Eight feline cadaveric distal radioulnar joints were included in the study, including six that were paraffin- and two that were polymethyl methacrylate-embedded. Each of the sections of the distal radioulnar joint and ligament were viewed macroscopically and microscopically using a dissection microscope and a standard light microscope with polarising capacity.

RESULTS

On gross examination, the distal radioulnar ligament could be seen as a triangular-shaped structure extending between the dorsal surface of the distal radius and ulna. The centre of the ligament had a greater density of tightly packed collagen fibres, while fibrocartilage was identified at the site of both the radial and ulnar entheses. Articular cartilage was noted to extend to the most proximal part of the bulbous portion of the distal ulna and corresponding axial aspect of the distal radius.

CONCLUSIONS AND RELEVANCE

In the cat, there appears to be a less extensive interosseous component of the distal radioulnar ligament compared with the dog and cheetah. Instead, the ligament follows the articular surfaces of the distal radius and ulna. These anatomical differences may account for increased rotation of the feline antebrachium and have clinical implications, particularly with regard to the management of antebrachiocarpal joint injuries.

The relation between radiographic manifestation and clinical characteristics of congenital radioulnar synostosis in children: A retrospective study from multiple centers

Objective

To review the radiographic manifestation and clinical appearance of children with congenital radioulnar synostosis (CRUS) retrospectively.

Study design

Retrospective cohort study of children with CRUS from multiple medical centers.

Results

A total of 329 patients (male 259, female 70) with an average age of 5.4 years (0.5-16 years old), were included in this study. In particular, 145 patients (145/329, 44.1%) demonstrated bilateral involvement, and 184 patients (left 123, right 61) demonstrated unilateral involvement. As for Clear and Omery (C&O) classification, most patients belonged to Type III, and then followed by Type IV. As for Chinese Multi-center Pediatric Orthopedic Study Group (CMPOS) classification, most patients belonged to Type III, and then followed by Type II and Type I. In C&O Type III, 92.03% patients demonstrated severe pronation. According to CMPOS classification, 92.98% Type I patients demonstrated neutral to mild pronation, 72.17% Type II patients demonstrated moderate pronation, and 92.03% Type III patients demonstrated severe pronation. The age distribution showed no significant difference between C&O Type II and IV (P = 0.96); the pronation ankylosis severity showed no significant difference between C&O Type II and IV (P = 0.387).

Conclusion

Although CRUS is a rare forearm deformity, there are certain relation between radiographic manifestation and clinical forearm functional restriction. CRUS patients of C&O or CMPOS Type III classification might suffer severe pronation deformity and warrant early intervention.

The influence of sagittal deformity of the distal radius on pronosupination: a cadaver study

We performed a cadaver study using seven fresh-frozen adult upper limbs to assess the impact of increasingly larger distal radial deformity in the sagittal plane on the range of motion in pronation/supination. Three palmar (20°, 30° and 40° angulations) and three dorsal (10°, 20° and 30° angulations) tilt deformities, without any radial shortening, were simulated by performing a radial osteotomy and using custom-made three-dimensional-printed anterior plates. We measured the maximum unconstrained pronation and supination before the osteotomy and after each induced deformation. There was a decrease in the median pronation and supination values for all palmar and dorsal tilt deformities. The pronation range was more impaired than the supination range, and dorsal tilt deformities caused the greatest loss in forearm rotation. Our results suggest that forearm rotation in both pronation and supination is reduced as soon as 10° to 20° distal radial deformity occurs in the palmar or dorsal direction.

Radiological and Anatomical Evaluation of First Metatarsal Pronation in Hallux Valgus Deformity: A Comparison Between Three Different Methods

A frontal plane metatarsal rotational (pronation) has been documented in a high percentage of hallux valgus patients. Pathoanatomical concepts leading to pronation are still debated. Nevertheless, there is no consensus on how to measure this component of the deformity. The aim of the present study was to compare three commonly used radiographic methods to measure the frontal plane deformity in hallux valgus deformity, such as 1. Round sign of the lateral edge of the first metatarsal head on anterior-posterior radiograph, 2. Non-weightbearing CT-scan and 3. Bernard's axial projection of the first metatarsal head. Afterwards, feet were dissected, and a direct measurement of the pronation was done. Our data showed that alpha angle measurements made through the Bernard's axial projection were closer with those obtained during the dissection compared to those made through the CT-scan. The main finding of our study is that osteoarthritic changes at the metatarso-sesamoid joint play an important role in severe hallux valgus cases. The proposed radiographic methods allow surgeons to verify whether rotation can be corrected during Hallux Valgus procedures and to determine which procedure may be the best for each patient.

Intra‑ and Interobserver Reliability of Yamaguchi's Method for the Assessment of First Metatarsal Pronation in Hallux Valgus Deformity

Pronation of the first metatarsal is a risk factor for the formation and progression of the hallux valgus deformity. Recently, Yamaguchi et al published a study that showed how the round sign increases on digitally reconstructed radiography taken from a CT scan when pronation is applied. In this study, the shape of the lateral edge of the first metatarsal head was evaluated on weightbearing dorsoplantar radiographs. Yamaguchi's signs were presented to observers after the visual presentation of each foot as an image. The best-fit circle was drawn using the PACS drawing function. Ninety radiographs of adults presenting hallux valgus deformities were classified as mild-to-moderate, based on hallux valgus angle and intermetatarsal angle. The global average observations were 3.72 ± 3.92 (range 2.3°-4.6°). The interclass correlation (Fleiss Kappa index κ = 0.225) and the Spearman correlation (0.16 of Kappa) coefficients were poor for interobserver measurements and statistically significant. Using the linear model, there was no significant variability between the repetitions corresponding to each observer (t-value -1.527, p value .127). Our findings show that the Yamaguchi method can be very subjective and should not be the exclusive technique to assess the rotation of the first metatarsal or head roundness.

Mathematical model of distal radius orientation

Distal radius orientation is important in evaluating Colles' fracture. In most cases, the wrist was protected by a bandage, splint, or cast. Therefore, it was difficult for the radiology technician to take perfect anteroposterior and lateral view radiographs. In this study, we build a mathematical model and calculate the pronation angle needed to produce dorsal tilt, which is a volar tilt in a perfect lateral view radiograph. The formulas are all incorporated into Excel to facilitate usage.

Sensor Verification and Analytical Validation of Algorithms to Measure Gait and Balance and Pronation/Supination in Healthy Volunteers

Numerous studies have sought to demonstrate the utility of digital measures of motor function in Parkinson’s disease. Frameworks, such as V3, document digital measure development: technical verification, analytical and clinical validation. We present the results of a study to (1) technically verify accelerometers in an Apple iPhone 8 Plus and ActiGraph GT9X versus an oscillating table and (2) analytically validate software tasks for walking and pronation/supination on the iPhone plus passively detect walking measures with the ActiGraph in healthy volunteers versus human raters. In technical verification, 99.4% of iPhone and 91% of ActiGraph tests show good or excellent agreement versus the oscillating table as the gold standard. For the iPhone software task and algorithms, intraclass correlation coefficients (ICCs) > 0.75 are achieved versus the human raters for measures when walking distance is >10 s and pronation/supination when the arm is rotated more than two times. Passively detected walking start and end time was accurate to approx. 1 s and walking measures were accurate to one unit, e.g., one step. The results suggest that the Apple iPhone and ActiGraph GT9X accelerometers are fit for purpose and that task and passively collected measures are sufficiently analytically valid to assess usability and clinical validity in Parkinson’s patients.

Coronal Plane Rotation of the Medial Column in Hallux Valgus: A Retrospective Case-Control Study

BACKGROUND

We previously reported an increase in pronation of the first metatarsal (M1) head relative to the ground in hallux valgus (HV) patients compared to controls. Still, the origin and location of this hyperpronation along the medial column is unknown. Recent studies showed that presence of progressive collapsing foot deformities (PCFDs), which is a condition frequently associated with HV, can strongly influence the medial column coronal plane alignment. The objective of this study was to assess the coronal rotation of the medial column bones in HV feet, HV feet with radiologic markers of PCFD, and controls. We hypothesized that hyperpronation in HV will originate from a combination of M1 intrinsic torsion and first tarsometatarsal joint malposition.

METHODS

The same cohort of 36 HV and 20 controls matched on age, gender, and body mass index was used. Previously, a validation of the measurements was carried out through a cadaveric study. Using these metrics, we assessed the coronal plane rotation of the navicular, medial cuneiform, and the M1 at its base and head with respect to the ground using weightbearing CT images. We measured the Meary angle and the calcaneal moment arm in our 36 HV subjects. We subdivided our cohort into an HV group and a potential PCFD HV group according to these measurements. Comparisons on medial column bones coronal rotation were performed between HV, PCFD HV, and control groups.

RESULTS

Twenty-two HV cases were included in the HV group and 14 in the PCFD HV group. Both groups presented an increase in pronation of the first metatarsal head relative to the ground when compared to the control group (P < .001). Comparing HV and controls showed an 8.3 degrees increase in pronation of M1 intrinsic torsion (P < .001) and a 4.7 degrees pronated malposition of the first tarsometatarsal joint (P = .02) in HV. A 9.7 degrees supinated malposition of the first naviculocuneiform joint (P < .001) was also observed in HV. Comparing PCFD HV and controls showed a significant increase in pronation of the navicular (respectively, 17.2 ± 5.4 and 12.3 ± 3.4 degrees, P = .007) and a 5.5 degrees increase in pronation of M1 intrinsic torsion (P = .02) in PCFD HV, without malposition of the first tarsometatarsal and naviculocuneiform joints.

CONCLUSION

Hyperpronation of the M1 head relative to the ground originated from both increases in pronation of M1 intrinsic torsion and first tarsometatarsal joint malposition in HV, although partially counterbalanced by a supinated malposition of the first naviculocuneiform joint. On the other hand, PCFD HV patients showed a generalized pronated position throughout the medial column from the navicular to the M1 head and may be related to the midfoot and hindfoot deformities frequently present in PCFD.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Should Diastatic Syndesmosis be Stabilized in Advanced Pronation-External Rotation Ankle Injuries? A Retrospective Cohort Comparison

OBJECTIVE

With or without screw stabilization for diastatic syndesmosis in advanced pronation-external rotation (PE) ankle injuries has not yet been well-determined. Both techniques were retrospectively compared to investigate the superiority of either of the two.

METHODS

A retrospective cohort study was carried out. From January 1, 2008, to December 31, 2017, 81 consecutive adult patients (average, 42 years; range, 18-78 years; 44 men and 37 women) with advanced PE ankle injuries (stage 3 or 4 PE type) were treated. After malleolar fractures were internally stabilized with screws and plates, the syndesmotic stability was rechecked by external rotation and hook tests. The necessity of cortical screw insertion to stabilize diastatic syndesmosis was decided by the individual orthopaedic surgeon. Postoperatively, a short leg splint was used for 6 weeks. The syndesmotic screw was removed based on the surgeon's policy. The removal of internal fixation for malleolar fractures was required after 1 year. The outcomes of both approaches were compared clinically, and ankle function was compared using the American Orthopaedic Foot and Ankle Society (AOFAS) score. For statistical comparison, the chi-square test was used for categorical data and the Mann-Whitney U test was used for numerical data.

RESULTS

Seventy-one patients (average, 40 years; range, 18-78 years; 40 men and 31 women) were followed for at least 1 year (87.7%; average, 2 years; range, 1-11 years). Group 1 (with syndesmotic stabilization) had 22 patients and Group 2 (without syndesmotic stabilization), 49 patients. The union rate in Group 1 patients was 100% (22/22), and in Group 2 patients, 91.8% (45/49; p = 0.17). One deep wound infection occurred in Group 1 patients and two in Group 2 patients. Syndesmosis re-diastasis occurred in 13.6% (3/22) of Group 1 patients and 30.6% (15/49) of Group 2 patients (p = 0.13). One syndesmotic screw broke at 6 months. Satisfactory ankle function according to the AOFAS score was noted in 86.4% (19/22) of Group 1 patients and 65.3% (32/49) of Group 2 patients (p = 0.07).

CONCLUSION

Insertion of syndesmotic screws to promote ligament healing after internal fixation of malleolar fractures in advanced PE ankle injuries may be reasonable.

Side-to-Side Difference of Metatarsal Rotation in Normal Individuals

BACKGROUND

A previous study defined the normal first metatarsal pronation angle (MPA) as <16 degrees and normal α angle as <18 degrees. The primary purpose of this study was to assess the side-to-side variation in first metatarsal pronation between feet in normal individuals.

METHODS

MPA and α angles were measured on standardized coronal weightbearing computed tomography slices. Pairedt tests were used to test significance of mean side-to-side differences in a population of 63 normal, asymptomatic individuals.

RESULTS

The mean side-to-side difference in first metatarsal pronation was 4.3 degrees (95% CI 3.3, 5.2 degrees) for MPA and 4.9 degrees (95% CI 3.8, 6.0 degrees) for α angle. The normative range for side-to-side difference was calculated as 12 degrees for MPA and 14 degrees for α angle, as defined by 2 SDs from the mean.

CONCLUSION

In a cohort of normal patients, the mean difference in first metatarsal pronation between sides was approximately 4 to 5 degrees based on MPA and α angle. However, considerable variation in differences was observed. These findings may be considered when assessing first metatarsal pronation using population-based values as it may influence thresholds for identifying pathology in an individual.

Imaging Findings and First Metatarsal Rotation in Hallux Valgus

BACKGROUND

Failure to identify and correct malrotation of the first metatarsal may lead to recurrent hallux valgus deformity. We aimed to identify the proportion of hallux valgus patients with increased first metatarsal pronation using weightbearing computed tomography (WBCT) and to identify the relationship with conventional radiographic measurements.

METHODS

WBCT scans were analyzed for 102 feet with a hallux valgus angle (HVA) and intermetatarsal angle (IMA) greater than or equal to 16 and 9 degrees, respectively. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle (SRA), and sesamoid position were measured on standardized coronal WBCT slices. Pronation was recorded as positive. Hindfoot alignment angle (HAA) was assessed using dedicated software. Pearson correlation and multiple regression analyses were used to assess differences between groups.

RESULTS

Mean HVA was 29.8±9.4 degrees and mean IMA was 14.1±3.7 degrees. Mean MPA was 11.9±5.8 (range 0-26) degrees and mean alpha angle was 11.9±6.8 (range -3 to 29) degrees. In a previous study, we demonstrated the upper limit of normal MPA as 16 degrees and alpha angle as 18 degrees. Based on these criteria, we identified abnormal metatarsal pronation in 32 feet (31.4%). We found a strong positive correlation between SRA and HVA/IMA (R = 0.67/0.60, respectively, P < .001). IMA and HAA weakly correlated with MPA and alpha angle (IMA: R = 0.26/0.27, respectively, P < .01; HAA: R = 0.26/0.27, respectively, P < .01). Regression analyses suggested that increasing IMA was the most significant radiographic predictor of increased pronation. In this cohort, there was no correlation between HVA or sesamoid position and MPA / alpha angle (HVA: P = .36/.12, respectively, sesamoid position, P = .86/.77, respectively).

CONCLUSION

In this cohort of 102 feet that met plain radiographic criteria for hallux valgus deformity, first metatarsal pronation was found abnormal in 31.4% of patients. We found a weak association between the IMA and hindfoot valgus, but not the HVA.

Distal Metatarsal Articular Angle in Hallux Valgus Deformity. Fact or Fiction? A 3-Dimensional Weightbearing CT Assessment

BACKGROUND

The Distal Metatarsal Articular Angle (DMAA) was previously described as an increase in valgus deformity of the distal articular surface of the first metatarsal (M1) in hallux valgus (HV). Several studies have reported poor reliability of this measurement. Some authors have even called into question its existence and consider it to be the consequence of M1 pronation resulting in projection of the round-shaped lateral edge of M1 head.Our study aimed to compare the DMAA in HV and control populations, before and after computer correction of M1 pronation and plantarflexion with a dedicated weightbearing CT (WBCT) software. We hypothesized that after computerized correction, DMAA will not be increased in HV compared to controls.

METHODS

We performed a retrospective case-control study including 36 HV and 20 control feet. In both groups, DMAA was measured as initially described on conventional radiographs (XR-DMAA) and WBCT by measuring the angle between the distal articular surface and the longitudinal axis of M1. Then, the DMAA was measured after computerized correction of M1 plantarflexion and coronal plane rotation using the α angle (3d-DMAA).

RESULTS

The XR-DMAA and the 3d-DMAA showed higher significant mean values in HV group compared to controls (respectively 25.9 ± 7.3 vs 7.6 ± 4.2 degrees, P < .001, and 11.9 ± 4.9 vs 3.3 ± 2.9 degrees, P < .001).Comparing a small subset of precorrected juvenile HV (n=8) and nonjuvenile HV (n=28) demonstrated no significant difference in the measure DMAA values. On the other hand, the α angle was significantly higher in the juvenile HV group (21.6 ± 9.9 and 11.4 ± 3.7 degrees; P = .0046).

CONCLUSION

Although the valgus deformity of M1 distal articular surface in HV is overestimated on conventional radiographs, comparing to controls showed that an 8.6 degrees increase remained after confounding factors' correction.

CLINICAL RELEVANCE

After pronation computerized correction, an increase in valgus of M1 distal articular surface was still present in HV compared to controls.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Association of First Metatarsal Pronation Correction With Patient-Reported Outcomes and Recurrence Rates in Hallux Valgus

BACKGROUND

The purpose of this study was to determine if a postoperative decrease in first metatarsal pronation on 3-dimensional imaging was associated with changes in patient-reported outcomes as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function, pain interference, and pain intensity domains or recurrence rates in patients with hallux valgus (HV) who undergo a first tarsometatarsal fusion (modified Lapidus procedure).

METHODS

Thirty-nine consecutive HV patients who met the inclusion criteria and underwent a modified Lapidus procedure had preoperative and ≥2-year postoperative PROMIS scores and had first metatarsal pronation measured on preoperative and at least 5-month postoperative weightbearing CT scans were included. Multivariable regression analyses were used to investigate differences in the change in PROMIS domains preoperatively and 2 years postoperatively between patients with "no change/increased first metatarsal pronation" and "decreased first metatarsal pronation." A log-binomial regression analysis was performed to identify if a decrease in first metatarsal pronation was associated with recurrence of the HV deformity.

RESULTS

The decreased first metatarsal pronation group had a significantly greater improvement in the PROMIS physical function scale by 7.2 points (P = .007) compared with the no change/increased first metatarsal pronation group. Recurrence rates were significantly lower in the decreased first metatarsal pronation group when compared to the no change/increased first metatarsal pronation group (risk ratio 0.25, P = .025).

CONCLUSION

Detailed review of this limited cohort of patients who underwent a modified Lapidus procedure suggests that the rotational component of the HV deformity may play an important role in outcomes and recurrence rates following the modified Lapidus procedure.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Repeatability of Weightbearing Computed Tomography Measurement of First Metatarsal Alignment and Rotation

BACKGROUND

Weightbearing computed tomography (WBCT) can be used to assess alignment and rotation of the first metatarsal. It is unknown whether these measures remain consistent on sequential WBCTs in the same patient when a patient's standing position may be different. The aim of this study was to establish the repeatability (test-retest) of measurements of first metatarsal alignment and rotation in patients without forefoot pathology on WBCT.

METHODS

We retrospectively identified 42 feet in 26 patients with sequential WBCT studies less than 12 months apart. Patients with surgery between scans, previous forefoot surgery or hallux rigidus were excluded. Hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured using digitally reconstructed radiographs. Two methods of calculating metatarsal rotation (metatarsal pronation angle [MPA] and alpha angle) were measured on standardized coronal CT slices. Interobserver agreement and test-retest repeatability were assessed using intraclass correlation coefficients (ICCs). Standard error of measurement (SEM) and minimally detectable change (MDC95) were calculated.

RESULTS

Interobserver agreement was excellent for HVA and IMA (ICC 0.96 and 0.90, respectively) and was good for MPA and alpha angle (ICC 0.81 and 0.80, respectively). There was excellent test-retest repeatability for HVA (ICC=0.90) and good test-retest repeatability for IMA (ICC=0.77). There was excellent test-retest repeatability for MPA (ICC=0.91) and good test-retest repeatability for alpha angle (ICC=0.87). The MDC95 was 4.6 degrees for MPA and 6.1 degrees for alpha angle. Five percent of patients had a difference outside of the MDC95 for the alpha angle, compared with 2% for the MPA.

CONCLUSION

Measurements of first metatarsal alignment and rotation are reliable between assessors and repeatable between sequential WBCTs in patients without forefoot pathology. Subtle differences in patient positioning during image acquisition do not significantly affect measurements, supporting the validity of this method of assessment in longitudinal patient care.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

The Effect of Forearm Shortening on Forearm Range of Motion

PURPOSE

Osseous shortening of the forearm is performed during forearm replantation; however, no large clinical reviews have discussed its effects on patient outcomes. A recent cadaver study demonstrated the progressive loss of forearm pronation/supination ranges of motion with increased shortening lengths using external fixation. Our study aimed to quantify the effects of shortening on passive forearm motion using internal fixation after 2, 4, and 6 cm of mid-forearm shortening.

METHODS

A volar Henry approach and direct approach to the ulna were used on 8 cadaveric specimens. The forearms were sequentially shortened by 2, 4, and 6 cm. Fixation was performed on the volar surfaces of the radius and ulna. Pronation and supination of the forearms were tested by applying 1 Nm of torque at baseline and after the fixation of both the radius and ulna using osteotomy. Radiographs and measurements were obtained at each phase to determine the maximum radial bow and radioulnar gap. Data were analyzed using a linear mixed-effects model.

RESULTS

Greater shortening of the radius and ulna led to progressively greater reductions in both pronation and supination range of motion. Larger differences were seen in supination at 2-4 cm of shortening and in pronation at 4-6 cm of shortening. Changes in supination were found to be associated with the radial bow and radioulnar gap; changes in pronation were found to be associated with the radial bow and radial bow's location.

CONCLUSIONS

This study demonstrates that quantifiable effects on passive forearm motion occur after osseous shortening of the forearm.

CLINICAL RELEVANCE

This information may improve surgeons' and patients' understanding of the changes in forearm motion expected after shortening in the setting of replantation or tumor resection or in the setting of limb salvage of a mangled extremity.

Assessing the Rotation of the First Metatarsal on Computed Tomography Scans: A Systematic Literature Review

BACKGROUND

Hallux valgus is a multiplanar deformity that is often treated on the basis of 2-dimensional (2D) parameters and radiographs. Recurrence rates after surgical correction remain high, and failure to correct pronation of the metatarsal is increasingly stipulated as being part of the problem. Multiple methods of assessing metatarsal pronation have been proposed.

METHODS

We performed a systematic literature review identifying studies that measured metatarsal pronation and torsion on computed tomography (CT) scans. Specific methodology, patient groups, results, and reliability assessments were all reported.

RESULTS

We identified 14 studies that fulfilled the inclusion criteria. Eleven studies measured 2D values on CT scan, and 3 studies used computer-based 3-dimensional (3D) modeling and artificial intelligence systems to help calculate pronation. Metatarsal pronation angle, α angle, sesamoid rotation angle, and measurements for torsion were the most commonly used methods. All angles and measurements were performed as 2D measurements, but the metatarsal pronation angle was also performed with 3D modeling. Reliability and reproducibility of the α angle and metatarsal pronation angle were excellent, despite being performed on studies with small numbers.

CONCLUSION

Multiple methods have been reported to demonstrate first metatarsal pronation on CT, of which the α angle and the metatarsal pronation angle are the most pragmatic and useful in a clinical setting. Further work is needed to further validate the reliability of these measurements in larger series and to identify normal pronation and metatarsal torsion on weightbearing imaging. Further work is required to determine whether addressing pronation reduces recurrence rates and improves outcomes in surgery for hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Effect of Systematic Corrective Exercises on the Static and Dynamic Balance of Patients with Pronation Distortion Syndrome: A Randomized Controlled Clinical Trial Study

Background:

The purpose of this study was to determine the effect of systematic corrective exercises on the static and dynamic balance of students with pronation distortion syndrome.

Methods:

In this randomized controlled clinical trial study, 30 volunteers were selected and randomly divided into the control and experimental groups (15 subjects per group). The experimental group performed systematic corrective exercises for 12 weeks, while the control group performed the routine exercise. Static and dynamic balance was evaluated before and after the interventions. The data were analyzed using independent and paired t-tests (P < 0.05).

Results:

The results showed significant improvement (P < 0.05) in the static and dynamic balance in the experimental group, but not in the control group. A significant difference was evident between the experimental and control groups in terms of static and dynamic balances, in static balance including Flamingo balance test (42.26 ± 5.35 vs. 10.13 ± 1.92) stabilometr (1.23 ± 0.48 vs. 3.71 ± 1.02), and in dynamic balance including star excursion balance test (anterior direction 82.4 ± 6.2 vs. 66.7 ± 6.9, Posterior-internal direction 87.8 ± 4.7 vs. 69.6 ± 6.3, posterior-external direction 86.06 ± 6.93 vs. 67.2 ± 6.2), stabilometr (3.8 ± 0.6 vs. 11.18 ± 1.8) (P < 0.05 for all variables).

Conclusions:

It can be concluded that systematic corrective exercises improve static and dynamic balance in students with pronation distortion syndrome and it could be recommended as modalities for these people.

Results after treatment of congenital radioulnar synostosis: a systematic review and pooled data analysis

Congenital radioulnar synostosis (CRUS) is one of the most common congenital disorders affecting the elbow and forearm, with the forearm being fixed in a range of positions usually varying from neutral rotation to severe pronation. The aim of this study, apart from a systematic review of all surgical procedures described for CRUS, is to derive any correlation between various influencing factors, outcomes and complications. This review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format by an electronic literature search of Ovid, MEDLINE and the Cochrane Library databases. Grading was according to the Newcastle-Ottawa scale and the Modified Coleman Methodology Score. Demographic data, surgical procedures, outcomes and complications were analyzed. Outcome data were pooled to establish means and ranges across all studies. Spearman correlations were performed. A total of 23 articles, showing a poor overall study quality (all Level of Evidence IV), met the inclusion criteria. A total of 374 forearms with a mean age of 6.7 years (2.0-18.8) were analyzed. Derotational surgeries were more commonly performed (91%) than motion-preserving surgeries (9%). The mean deformity improved from 64.8° pronation (-75° to 110°) to a mean of 2.8° pronation (-50° to 80°). In total, 17.9% of patients presented with complications. A significant correlation was noted between age and major complications, proximal osteotomies and complications, and postoperative loss of reduction and double level osteotomies as the primary treatment modality. Most of the complications occurred above the threshold of 65-70° of correction and in children 7 years and above. Surgery is essential to improve the quality of life of children with CRUS. However, each type of surgery is associated with complications, along with the respective hardware being used in rotation osteotomies. Caution is, nevertheless, warranted in interpreting these results in view of the inherent limitations of the included studies.

The Assessment of First Metatarsal Rotation in the Normal Adult Population Using Weightbearing Computed Tomography

BACKGROUND

The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT).

METHODS

WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus-first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs).

RESULTS

Mean MPA was 5.5 ± 5.1 (range, -6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, -5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was -5 to 16 degrees for MPA and -4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P < .001).

CONCLUSION

Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

A Three-Dimensional Printed Foot Orthosis for Flexible Flatfoot: An Exploratory Biomechanical Study on Arch Support Reinforcement and Undercut

The advancement of 3D printing and scanning technology enables the digitalization and customization of foot orthosis with better accuracy. However, customized insoles require rectification to direct control and/or correct foot deformity, particularly flatfoot. In this exploratory study, we aimed at two design rectification features (arch stiffness and arch height) using three sets of customized 3D-printed arch support insoles (R+U+, R+U-, and R-U+). The arch support stiffness could be with or without reinforcement (R+/-) and the arch height may or may not have an additional elevation, undercutting (U+/-), which were compared to the control (no insole). Ten collegiate participants (four males and six females) with flexible flatfoot were recruited for gait analysis on foot kinematics, vertical ground reaction force, and plantar pressure parameters. A randomized crossover trial was conducted on the four conditions and analyzed using the Friedman test with pairwise Wilcoxon signed-rank test. Compared to the control, there were significant increases in peak ankle dorsiflexion and peak pressure at the medial midfoot region, accompanied by a significant reduction in peak pressure at the hindfoot region for the insole conditions. In addition, the insoles tended to control hindfoot eversion and forefoot abduction though the effects were not significant. An insole with stronger support features (R+U+) did not necessarily produce more favorable outcomes, probably due to over-cutting or impingement. The outcome of this study provides additional data to assist the design rectification process. Future studies should consider a larger sample size with stratified flatfoot features and covariating ankle flexibility while incorporating more design features, particularly medial insole postings.

Percutaneous Bunionette Correction Without Fixation: Clinical Results and Radiographic Evaluations Including Rotation of Metatarsal Head and Sagittal Angle Change of Fifth Metatarsal

Bunionette deformities have been treated as an analog of hallux valgus, and the surgical techniques are similar. Most commonly anteroposterior image is evaluated pre- and postoperatively. To our knowledge, only one study has evaluated changes on the lateral radiograph and no study has evaluated changes in rotation of the fifth metatarsal head postoperatively. In percutaneous bunionette correction using a burr for osteotomy, shortening of the fifth metatarsal and elevation of the metatarsal head are inevitable. Without fixation, there is also a possibility of rotational change to the metatarsal head. We measured parameters on anteroposterior and lateral weightbearing radiographs in 18 feet pre- and postoperatively. Rotation of the fifth metatarsal head was graded according to the medial tubercle location. We also evaluated angular change of the fifth metatarsal on weightbearing lateral radiographs. Percutaneous bunionette correction without fixation could achieve satisfactory clinical and radiographic results, with less complication, when compared with previously published outcomes of open and percutaneous surgery with fixation. In this surgical method, bunionette is corrected in 3 dimensions. To our knowledge, this is the first study to evaluate rotation of the metatarsal head and change in the sagittal angle of the fifth metatarsal after bunionette correction.

Correlation of Different Methods of Measuring Pronation of the First Metatarsal on Weightbearing CT Scans

BACKGROUND

There is no consensus in the foot and ankle literature regarding how to measure pronation of the first metatarsal in patients with hallux valgus. The primary purpose of this study was to compare 2 previously published methods for measuring pronation of the first metatarsal and a novel 3-dimensional measurement of pronation to determine if different measurements of pronation are associated with each other.

METHODS

Thirty patients who underwent a modified Lapidus procedure for their hallux valgus deformity were included in this study. Pronation of the first metatarsal was measured on weightbearing computed tomography (WBCT) scans using the α angle with reference to the floor, a 3-dimensional computer-aided design (3D CAD) calculation with reference to the second metatarsal, and a novel method, called the triplanar angle of pronation (TAP), that included references to both the floor (floor TAP) and base of the second metatarsal (second TAP). Pearson's correlation coefficients were used to determine if the 3 calculated angles of pronation correlated to each other.

RESULTS

Preoperative and postoperative α angle and 3D CAD had no correlation with each other (r = 0.094, P = .626 and r = 0.076, P = .694, respectively). Preoperative and postoperative second TAP and 3D CAD also had no correlation (r = 0.095, P = .624 and r = 0.320, P = .09, respectively). However, preoperative and postoperative floor TAP and α angle were found to have moderate correlations (r = 0.595, P = .001 and r = 0.501, P = .005, respectively).

CONCLUSION

The calculation of first metatarsal pronation is affected by the reference and technique used, and further work is needed to establish a consistent measurement for the foot and ankle community.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Frontal Plane Rotation of the First Ray in Hallux Valgus using Standing Computerized Tomography (CT)

The purpose of the present study was to analyze the difference in frontal plane rotation of the entire first ray in patients with and without hallux valgus using standing weightbearing computed tomography (CT). Ten feet of 10 patients with hallux valgus and 36 feet of 36 patients without hallux valgus were examined. Standing weightbearing CT scans and radiographs were taken for all subjects. Frontal plane measurements of the sesamoid apparatus, first metatarsal head, first metatarsal base, and medial cuneiform were performed. Frontal plane rotation of the first tarsometatarsal joint and intrinsic first metatarsal torsion was calculated. An independent 2 sample t test was used to compare means of outcomes of interest across control and treatment groups. Statistical significance was set at an alpha level of 0.05. There was a significant increase in pronation of the sesamoid apparatus (23.49° vs 6.60°) and first metatarsal head (17.79° vs 9.81°) in patients with hallux valgus. There was a significant increase in first metatarsal torsion toward pronation in patients with hallux valgus (22.28° vs 13.52°). No significant difference was detected in the rotation at the first tarsometatarsal joint or the frontal plane orientations of the first metatarsal base and medial cuneiform. By examining the frontal plane position of the entire first ray during weightbearing using standing CT in patients with and without hallux valgus, we determined the level at which pronation originates to be within the first metatarsal bone rather than the first tarsometatarsal joint.

Custom-Made Foot Orthoses as Non-Specific Chronic Low Back Pain and Pronated Foot Treatment

Excessive foot pronation has been reported as being related to chronic low back pain symptoms and risk factors in sports-specific pathologies. Compensating custom-made foot orthotics treatment has not been entirely explored as an effective therapy for chronic low back pain (CLBP). This study aims to observe the effects of custom-made foot orthoses, in subjects with foot pronation suffering from CLBP. A total of 101 patients with nonspecific CLBP and a pronated foot posture index (FPI) were studied. They were randomized in two groups: an experimental one (n = 53) used custom-made foot orthotics, and the control group (n = 48) were treated with non-biomechanical effect orthoses. The CLBP was measured using the Oswestry Disability Index (ODI) Questionnaire and a visual analogue scale (VAS), both for lower back pain. The symptoms were evaluated twice, at first when the subject was included in the study, and later, after 4 weeks of treatment. The analysis of outcomes showed a significant decrease in CLBP in the custom-made foot orthoses participants group (p < 0.001 ODI; p < 0.001 VAS). These findings suggest that controlling excessive foot pronation by using custom-made foot orthoses may significantly contribute to improving CLBP.

The Assessment of First Metatarsal Rotation in the Normal Adult Population Using Weightbearing Computed Tomography

BACKGROUND

The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT).

METHODS

WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus-first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs).

RESULTS

Mean MPA was 5.5 ± 5.1 (range, -6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, -5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was -5 to 16 degrees for MPA and -4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P < .001).

CONCLUSION

Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Assessment of Selected Spatio-Temporal Gait Parameters on Subjects with Pronated Foot Posture on the Basis of Measurements Using OptoGait. A Case-Control Study

Walking is part of daily life and in asymptomatic subjects it is relatively easy. The physiology of walking is complex and when this complex control system fails, the risk of falls increases. As a result, gait disorders have a major impact on the older adult population and have increased in frequency as a result of population aging. Therefore, the OptoGait sensor is intended to identify gait imbalances in pronating feet to try to prevent falling and injury by compensating for it with treatments that normalize such alteration. This study is intended to assess whether spatiotemporal alterations occur in the gait cycle in a young pronating population (cases) compared to a control group (non-pronating patients) analyzed with OptoGait. Method: a total of n = 142 participants consisting of n = 70 cases (pronators) and n = 72 healthy controls were studied by means of a 30 s treadmill program with a system of 96 OptoGait LED sensors. Results: Significant differences were found between the two groups and both feet in stride length and stride time, gait cycle duration and gait cadence (in all cases p < 0.05). Conclusions: pronating foot posture alters normal gait patterns measured by OptoGait; this finding presents imbalance in gait as an underlying factor. Prevention of this alteration could be considered in relation to its relationship to the risk of falling in future investigations.

Functional Morphology of the Feeding Apparatus of the Snaggletooth Shark, Hemipristis elongata (Carcharhiniformes: Hemigaleidae)

The anatomy of the feeding apparatus of the snaggletooth shark, Hemipristis elongata (Klunzinger, 1871) is illustrated in detail from the dissection of three heads. Two new muscles are described: the Adductor mandibularis internus and the Levator mandibularis. A subdivision of the Levator palatoquadrati is described and named the Pronator subdivision of the Levator palatoquadrati. Also, eight new anatomical features associated with the mandibular arch and with the chondrocranium (CR) are described. Three are cartilages: the suprapalatine cartilages, the craniopalatoquadrate cartilage and the calcified Meckelian dental fold. The remaining five features are processes: the Pronator process of the palatoquadrate (PQ), the Levator palatoquadrati alpha process, the proquadrate process, the ectorbital process (ECP) and the Meckelian Intermandibularis ridge. Some of them are not restricted to H.elongata. The function of these new muscles and anatomical features is discussed and a hypothesis about the functional morphology of the feeding apparatus of the snaggletooth shark is proposed. The extent and the assumptive importance of the pronation of the mandibular arch in the snaggletooth shark feeding behaviour is described and discussed. An alternative for the main function of the Levator palatoquadrati as hypothesized by Motta et al. (1997) and Wilga et al. (2001) is proposed for the families Hemigaleidae, Carcharhinidae and Sphyrnidae. We anticipate this muscle is more involved in the pronation rather than in the protrusion of the mandibular arch.

Crosstalk in Mechanomyographic Signals From Elbow Flexor Muscles During Submaximal to Maximal Isometric Flexion, Pronation, and Supination Torque Tasks

This study analyzed the crosstalk in mechanomyographic (MMG) signals from elbow flexors during isometric muscle actions from 20% to 100% maximum voluntary isometric contraction (MVIC). Twenty-five young, healthy, male participants performed the isometric elbow flexion, forearm pronation, and supination tasks at an elbow joint angle of 90 deg. The MMG signals from the biceps brachii (BB), brachialis (BRA), and brachioradialis (BRD) muscles were recorded using accelerometers. The cross-correlation coefficient was used to quantify the crosstalk in MMG signals, recorded in a direction transverse to muscle fiber axis, among the muscle pairs (P1: BB and BRA, P2: BRA and BRD, and P3: BB and BRD). In addition, the MMG RMS and MPF were quantified. The mean normalized RMS and mean MPF exhibited increasing (r > 0.900) and decreasing (r < -0.900) trends, respectively, with increases in the effort levels in all three tasks. The magnitude of crosstalk ranged from 0.915% to 21.565% in all three muscle pairs. The crosstalk was found to exhibit high positive correlations with submaximal to maximal flexion [P1 (r = 0.970), P2 (r = 0.951), and P3 (r = 0.824)], pronation [P1 (r = 0.811), P2 (r = 0.763), and P3 (r = 0.901)] and supination [P1 (r = 0.898), P2 (r = 0.838), and P3 (r = 0.852)] torque levels (eight out of nine p-values were < 0.05). Regardless of the high positive correlation between crosstalk and level of effort, the crosstalk remained at a low range (0.915-21.565%) with increases in the torque levels.

The Rotational Positioning of the Bones in the Medial Column of the Foot: A Weightbearing CT Analysis

BACKGROUND

Malrotation of medial column bones of the foot has been advocated as an important factor in foot conditions such as hallux valgus and progressive collapsing foot deformity. Although stated as a deformity component, variances of normality in the general population are not completely understood. This study intended to describe the rotational profile of all medial column bones using weightbearing computed tomography (WBCT) images in a cohort of patients with different foot and ankle problems.

METHODS

In this retrospective study, 110 feet of 95 consecutive patients that received a WBCT for assessment of different foot and ankle pathologies were included. Measurements were performed by a blinded fellowship-trained orthopedic foot and ankle surgeon. Rotation of the navicular, medial cuneiform, proximal and distal first metatarsal as well as proximal phalanx of the first toe were recorded. Positive values were considered pronation and negative values were considered supination. Rotational profile of each bone/ segment was assessed by ANOVA and comparison between each segment was performed using Wilcoxon Each-Pair analysis. P-values of less than 0.05 were considered significant.

RESULTS

On average, a rotational positioning in pronation (internal rotation) was observed for all medial column bones. The navicular (43.2°, CI 41.1°-45.3°) and the proximal metatarsal (33.9°, CI 31.8°-36.0°) showed the highest mean rotation values. The medial cuneiform presented the lowest mean pronation (6.1°, CI 4.0°-8.3°). Comparison between each bone segment demonstrated statistically significant differences of rotational alignment for the different bones (p<0.0001), with the exception of the distal metatarsal and proximal phalanx, that had similar amounts of pronation. A zig-zag rotational pattern of alignment was observed from proximal to distal, with relative supination/pronation of adjacent medial column bones.

CONCLUSION

The overall rotational profile of medial column bones was found to be in absolute pronation, most pronounced at the navicular and proximal first metatarsal, with significant differences in the amount of pronation when comparing most of the medial column bones. The presented data may be utilized as reference/ baseline values of medial column rotation, supporting future prospective, comparative and controlled studies.Level of Evidence: IV.

Feature Analysis of Smart Shoe Sensors for Classification of Gait Patterns

Gait analysis is commonly used to detect foot disorders and abnormalities such as supination, pronation, unstable left foot and unstable right foot. Early detection of these abnormalities could help us to correct the walking posture and avoid getting injuries. This paper presents extensive feature analyses on smart shoes sensor data, including pressure sensors, accelerometer and gyroscope signals, to obtain the optimum combination of the sensors for gait classification, which is crucial to implement a power-efficient mobile smart shoes system. In addition, we investigated the optimal length of data segmentation based on the gait cycle parameters, reduction of the feature dimensions and feature selection for the classification of the gait patterns. Benchmark tests among several machine learning algorithms were conducted using random forest, k-nearest neighbor (KNN), logistic regression and support vector machine (SVM) algorithms for the classification task. Our experiments demonstrated the combination of accelerometer and gyroscope sensor features with SVM achieved the best performance with 89.36% accuracy, 89.76% precision and 88.44% recall. This research suggests a new state-of-the-art gait classification approach, specifically on detecting human gait abnormalities.

Finite Element Analysis of Generalized Ligament Laxity on the Deterioration of Hallux Valgus Deformity (Bunion)

Hallux valgus is a common foot problem affecting nearly one in every four adults. Generalized ligament laxity was proposed as the intrinsic cause or risk factor toward the development of the deformity which was difficult to be investigated by cohort clinical trials. Herein, we aimed to evaluate the isolated influence of generalized ligament laxity on the deterioration using computer simulation (finite element analysis). We reconstructed a computational foot model from a mild hallux valgus participant and conducted a gait analysis to drive the simulation of walking. Through parametric analysis, the stiffness of the ligaments was impoverished at different degrees to resemble different levels of generalized ligament laxity. Our simulation study reported that generalized ligament laxity deteriorated hallux valgus by impairing the load-bearing capacity of the first metatarsal, inducing higher deforming force, moment and malalignment at the first metatarsophalangeal joint. Besides, the deforming moment formed a deteriorating vicious cycle between hallux valgus and forefoot abduction and may result in secondary foot problems, such as flatfoot. However, the metatarsocuneiform joint did not show a worsening trend possibly due to the overriding forefoot abduction. Controlling the deforming load shall be prioritized over the correction of angles to mitigate deterioration or recurrence after surgery.

Randomized Clinical Trial: The Effect of Exercise of the Intrinsic Muscle on Foot Pronation

Background: There is little scientific evidence regarding the effectiveness of strengthening exercises on the foot's intrinsic musculature in improving the lower limb on the statics and dynamics in healthy individuals. Method: To evaluate the effect on foot posture with regard to the reinforcement of the short foot exercise (SFE) compared to another without a recognized biomechanical action, which we called the "non-biomechanical function" (NBF) exercise. A randomized clinical trial was carried out with 85 asymptomatic participants with a bilateral Foot Posture Index (FPI) greater than 6 points. An experimental group (n = 42) did SFE training and a control group (n = 43) carried out NBF exercises. The foot posture was evaluated twice via the navicular drop (ND) test, and the FPI was assessed on the day of inclusion in the study (pre-intervention) and after four weeks of training (post-intervention). Results: Statistically significant values were not found in foot posture between the experimental and the control groups when comparing before and after the training. However, the foot posture was modified in both groups with respect to its initial state, and the ND value decreased. Conclusions: SFE could be considered a useful tool to deal with pathologies whose etiology includes excessive pronation of the foot.

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.