Effects of head flexion posture on the multidirectional static force capacity of the neck

BackgroundNeck muscle force protects vertebral alignment and resists potentially injurious loading of osteoligamentous structures during head impacts. As the majority of neck muscles generate moments about all three planes of motion, it is not clear how the force capacity of the neck might be modulated by direction of force application and head posture. The aim of our study was to measure the multidirectional moment-generating capacity of the neck and to evaluate effects of 20° of head flexion, a common head position in contact sports, on the measured capacity.MethodsWe conducted a cross-sectional study, with 25 males, 20–30 years old, performing maximum voluntary contractions, with ballistic intent, along eight directions, set at 45° intervals in the horizontal plane of the head. Three-dimensional moments at C₃ and T₁ were calculated using equations of static equilibrium. The variable of interest was the impulse of force generated from 0–50 ms. Effects of direction of force application and head posture, neutral and 20° flexion, were evaluated by two-way analysis of variance and linear regression.FindingsImpulse of force was lower along diagonal planes, at 45° from the mid-sagittal plane, compared to orthogonal planes (P < 0.001). Compared to neutral posture, head flexion produced a 55.2% decrease in impulse capacity at C₃ and 45.9% at T₁.InterpretationThe risk of injury with head impact would intrinsically be higher along diagonal planes and with a 20° head down position due to a lower moment generating capacity of the neck in the first 50 ms of force application.     

Correlations between ankle–foot impairments and dropped foot gait deviations among stroke survivors

BackgroundThe purpose of this paper is to 1) evaluate the relationship between ankle kinematics during gait and standardized measures of ankle impairments among sub-acute stroke survivors, and 2) compare the degree of stroke-related ankle impairment between individuals with and without dropped foot gait deviations.MethodsFifty-five independently ambulating stroke survivors participated in this study. Dropped foot was defined as decreased peak dorsiflexion during the swing phase and reduced ankle joint motion in stance. Standardized outcome measures included the Chedoke–McMaster Stroke Assessment (motor impairment), Modified Ashworth Scale (spasticity), Medical Research Council (muscle strength), passive and active range of motion, and isometric muscle force.FindingsFoot impairment was not related to peak dorsiflexion during swing (r = ? 0.17, P = 0.247) and joint motion during stance (r = 0.05, P = 0.735). Active (r = 0.45, P < 0.001) and passive (r = 0.48, P < 0.001) range of motion was associated with stance phase joint motion. Peak dorsiflexion during swing was related to isometric dorsiflexor muscle force (r = ? 0.32, P = 0.039). Individuals with dropped foot demonstrated greater motor impairment, plantarflexor spasticity and ankle muscle weakness compared to those without dropped foot.InterpretationOur investigation suggests that ankle–foot impairments are related to ankle deviations during gait, as indicated by greater impairment among individuals with dropped foot. These findings contribute to a better understanding of gait-specific ankle deviations, and may lead to the development of a more effective clinical assessment of dropped foot impairment.     

Preliminary Report: Biomechanics of Vertebral Artery Segments C1-C6 During Cervical Spinal Manipulation

ObjectiveThe purpose of this study was to measure strains in the human vertebral artery (VA) within the cervical transverse foramina and report the first results on the mechanical loading of segments of the VA during spinal manipulation of the cervical spine.MethodsEight piezoelectric ultrasound crystals of 0.5-mm diameter were sutured into the lumen of the left and right VA of one cadaver. Four hundred–nanosecond ultrasound pulses were sent between the crystals to measure the instantaneous lengths of the VA segments (total segments n = 14) at a frequency of 200 Hz. Vertebral artery engineering strains were then calculated from the instantaneous lengths during cervical spinal range of motion testing, chiropractic cervical spinal manipulation adjustments, and vertebrobasilar insufficiency testing.ResultsThe results of this study suggest complex and nonintuitive strain patterns of the VA within the cervical transverse foramina. Consistent (for 2 chiropractors) and repeatable (for 3 repeat measurements for each chiropractor) elongation and shortening of adjacent VA segments were observed simultaneously and could not be explained with a simple model of neck movement. We hypothesized that they were caused by variations in the location and stiffness of the VA fascial attachments to the vertebral foramina and by coupled movements of the cervical vertebrae. However, in agreement with previous work on VA strains proximal and distal to the cervical transverse foramina, strains for cervical spinal manipulations were consistently lower than those obtained for cervical rotation.ConclusionsAlthough general conclusions should not be drawn from these preliminary results, the findings of this study suggest that textbook mechanics of the VA may not hold, that VA strains may not be predictable from neck movements alone, and that fascial connections within the transverse foramina and coupled vertebra movements may play a crucial role in VA mechanics during neck manipulation. Furthermore, the engineering strains during cervical spinal manipulations were lower than those obtained during range of motion testing, suggesting that neck manipulations impart stretches on the VA that are well within the normal physiologic range of neck motion.     

Shoulder and elbow kinematics during the Mallet score in obstetrical brachial plexus palsy

BackgroundThe physical signs of obstetrical brachial plexus palsy range from temporary upper-limb dysfunction to a lifelong impairment and deformity in one arm. The aim of this study was to analyze the kinematics of the upper limb and to evaluate the contribution of glenohumeral and scapulothoracic joints of obstetrical brachial plexus palsy children.MethodsSix children participated in this study: 2 males and 4 females with a mean age of 11.7 years. Three patients had a C5, C6 lesion and 3 had a C5, C6, C7 lesion. They were asked to perform five tasks based on the Mallet scale and the kinematic data were collected using the Fastrak electromagnetic tracking device.FindingsThe scapulothoracic protraction and posterior tilt were significantly increased in the involved limb during the hand to mouth task (p = 0.006 and p = 0.015 respectively). The scapulothoracic Protraction/glenohumeral Elevation ratio was significantly increased in the involved limb during the hand to neck task (p = 0.041) and the elevation task (p = 0.015). The ratios of scapulothoracic Tilt on the three glenohumeral excursion angles were significantly increased during the hand to mouth task (p ≤ 0.041). The scapulothoracic Mediolateral/glenohumeral Elevation ratio was significantly increased in the involved limb during the elevation task (p = 0.038). The glenohumeral elevation excursion was significantly decreased in the involved limb during the hand to neck task (p < 0.001) and the elevation task (p = 0.0003).InterpretationThis study gives us information about the greater contribution of the scapulothoracic joint to shoulder motion for affected arm of obstetrical brachial plexus palsy patients compared to their unaffected arm. Kinematic analysis could be useful in shoulder motion evaluation during the Mallet score and to evaluate outcomes after surgery.     

Differences in the kinematics of the cervical and thoracic spine during functional movement in individuals with or without chronic neck pain: a systematic review

BackgroundChronic neck pain is common, impacting a person’s ability to complete functional tasks. One method of quantifying functional movement is three dimensional (3D) motion analysis, however, it is unknown whether it may detect alterations in movement kinematics in individuals with neck pain.ObjectiveTo systematically review studies to determine possible differences in cervical and thoracic kinematics during functional movement as measured by 3D motion analysis in individuals with neck pain compared to controls.Data sourcesMedline, Amed, Scopus, Cochrane, Embase, CINAHL searched on 11/11/2017.Study selectionStudies reported 3D kinematics of functional movement (based on real-world situational biomechanics, i.e., multi-planar movements) of the cervical and thoracic spine in individuals with and without neck pain.Study appraisal and synthesisTwo reviewers assessed study quality; studies were summarised using discussion.ResultsFour thousand four hundred and sixteen title/abstracts were screened, 11 full texts retrieved. Common reasons for exclusion were participants ≤8 years of age and studies that did not investigate functional movement. Included studies (n = 5) used 3D motion analysis to assess kinematics during functional tasks including typing, gaming and resting posture. Participants with neck pain displayed greater neck flexion postures, reduced head velocity and smoothness of movement.LimitationsVariations in measurement methods and participant samples prevented meta-analysis.ConclusionThough few studies were identified, altered kinematics were observed in individuals with neck pain, suggesting further research examining cervical spine kinematics is warranted. Recognising kinematic differences is important for clinicians to identify possible movement risk factors in individuals with neck pain that may be targeted with treatment.Systematic review registration number PROSPEROCRD42017076053.     

Effects of footwear and stride length on metatarsal strains and failure in running

BackgroundThe metatarsal bones of the foot are particularly susceptible to stress fracture owing to the high strains they experience during the stance phase of running. Shoe cushioning and stride length reduction represent two potential interventions to decrease metatarsal strain and thus stress fracture risk.MethodsFourteen male recreational runners ran overground at a 5-km pace while motion capture and plantar pressure data were collected during four experimental conditions: traditional shoe at preferred and 90% preferred stride length, and minimalist shoe at preferred and 90% preferred stride length. Combined musculoskeletal – finite element modeling based on motion analysis and computed tomography data were used to quantify metatarsal strains and the probability of failure was determined using stress-life predictions.FindingsNo significant interactions between footwear and stride length were observed. Running in minimalist shoes increased strains for all metatarsals by 28.7% (SD 6.4%; p < 0.001) and probability of failure for metatarsals 2–4 by 17.3% (SD 14.3%; p ≤ 0.005). Running at 90% preferred stride length decreased strains for metatarsal 4 by 4.2% (SD 2.0%; p ≤ 0.007), and no differences in probability of failure were observed.InterpretationsSignificant increases in metatarsal strains and the probability of failure were observed for recreational runners acutely transitioning to minimalist shoes. Running with a 10% reduction in stride length did not appear to be a beneficial technique for reducing the risk of metatarsal stress fracture, however the increased number of loading cycles for a given distance was not detrimental either.     

Characteristics of thoracic and lumbar movements during gait in lumbar spinal stenosis patients before and after decompression surgery

BackgroundAlthough gait analysis has been previously conducted for lumbar spinal stenosis patients, the vertebral segmental movements, such as of the thoracic and lumbar regions, and whether the spinal movement during gait changes after decompression surgery remain unclear.MethodsTen patients with lumbar spinal stenosis and 10 healthy controls participated. Clinical outcomes were assessed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and Visual Analogue Scale. Spinal kinematic data of the participants during gait were acquired using a three-dimensional motion analysis system. The trunk (whole spine), thoracic, and lumbar flexion and pelvic tilting values were calculated. Spinal kinematic data and clinical outcomes were collected preoperatively and 1 month postoperatively for the patients.FindingsCompared to that observed preoperatively, the clinical outcomes significantly improved at 1 month postoperatively. In the standing position, the preoperative lumbar extension of the patients was significantly smaller than that of the controls. Moreover, during gait, the lumbar flexion relative to the standing position of the patients was smaller than that of the controls preoperatively, and increased at 1 month postoperatively. The sum of the thoracic and lumbar flexion values during gait negatively correlated with the score for leg pain.InterpretationThe epidural pressure of lumbar spinal stenosis patients is known to be higher than that of normal subjects during gait, and to decrease during walking with lumbar flexion. Preoperatively, smaller thoracic and lumbar flexion movements during gait relative to the standing position cannot decrease epidural pressure; as a result, severe leg pain might be induced.     

Comparison Between Neck Pain Disability and Cervical Range of Motion in Patients With Episodic and Chronic Migraine: A Cross-Sectional Study

ObjectiveThe purpose of this study was to evaluate neck pain–related disability and cervical range of motion (CROM) in patients with episodic migraine (EM) and chronic migraine (CM) and to examine the correlation of both outcomes.MethodsThis cross-sectional study consisted of 91 patients with EM and 34 with CM. Cervical range of motion was measured with the CROM device, and pain during the cervical movement was recorded. Self-reported disability related to neck pain was assessed with the Neck Disability Index.ResultsPatients with CM showed higher Neck Disability Index scores and more moderate and severe disability (P = .01). Severe disability as a result of neck pain was associated with 7.6-fold risk of developing CM (P = .003). No significant differences in CROM were identified between groups. Moderate negative correlations between CROM and disability were found for 4 motions within the CM group (− 0.60 < r < − 0.39) and with 3 in the EM group (− 0.48 < − 0.45). Disability was positively and moderately correlated to pain evoked during CROM in both groups (0.34 < r < 0.51).ConclusionThis study found that neck pain was highly prevalent in patients with migraine. Neck pain–related disability increased with increased frequency of the migraine attacks and was associated with the risk of migraine chronicity. The correlation between CROM and neck pain disability was more evident in patients with CM and in patients with pain during cervical movement.     

Changes in Vertebral Artery Blood Flow in Different Head Positions and Post–Cervical Manipulative Therapy

ObjectiveThe objective of this study was to investigate the hemodynamics of blood flow through the V3 region of the vertebral artery contralateral to the side manipulated during different rotary head positions and post–cervical spinal manipulation.MethodsThis quasi-experimental study was performed on 25 healthy, asymptomatic participants, both male and female, between 20 and 30 years of age. Each participant presented with a C0/C1 or C1/C2 cervical facet restriction (as determined by motion palpation). Participation was voluntary, and participants had no symptoms of vertebrobasilar artery insufficiency or contraindications to cervical spinal manipulation. Doppler ultrasound was used to measure vertebral artery blood flow (V3 region) hemodynamics, contralateral side of manipulation, as close to C1/C2 region as possible in 4 positions of cervical rotation (neutral, 45°, maximum, and post-manipulation neutral). Doppler ultrasound parameters included peak systolic flow velocity, end diastolic flow velocity, mean flow velocity, vessel diameter, and flow rate. The nonparametric Friedman test was used for analysis across each head and neck position, and post manipulation.ResultsNo clinical or statistically significant results (P > .05) were found for any of the hemodynamic parameters in any of the head positions.ConclusionsHemodynamic measurements of the V3 region of the vertebral artery do not show significant changes in the measured head positions or following manipulation of the upper cervical spine in patients without pre-existing risk factors.     

Interexaminer agreement of clinical examination of the neck in manual medicine

ObjectivesTo assess interexaminer agreement in a structured, manual, clinical examination of the neck. To correlate these data with the score in a functional questionnaire (a validated, French-language version of the neck pain and disability scale).PatientsFifty-nine ambulatory patients (26 males and 33 females, mean ± SD age: 46.3 ± 12 yrs) with common neck pain but no radiation below the elbow.MethodsTwo medical practitioners (a junior and a senior consultant) assessed neck rotation (in degrees) and the presence of pain during maximum neck flexion and extension, muscle palpation trapezius, levator scapulae, splenius cervicis, semispinalis) and cervical spine palpation. Cohen's kappa coefficient was calculated for qualitative variables. Angular rotational values (as a continuous variable) were compared using the p coefficient. Pearson coefficient was used to correlate the number of tender spots to the results of the questionnaire.ResultsThere was no significant interexaminer difference (±10°) in the neck rotation measurement. Kappa was (i) 0.71 and 0.76 for pain in flexion or extension, respectively, (ii) 0.44 on average for palpation of various muscles and (iii) 0.53 on average for cervical spine palpation. The number of tender spots correlated strongly with the questionnaire score (Pearson's coefficient: 0.35; p = 0.007).ConclusionThe interexaminer agreement for our clinical examination was moderate. The number of tender spots correlated strongly with the functional impairment. Pain at the lower attachment of the levator scapulae was associated with dysfunction of the median or upper cervical spine.     

The influence of different sitting postures on head/neck posture and muscle activity

To date the influence that specific sitting posture has on the head/neck posture and cervico-thoracic muscle activity has been insufficiently investigated. Therefore the aim of this study was to investigate whether three different thoraco-lumbar sitting postures affect head/neck posture and cervico-thoracic muscle activity.Twenty (10 men, 10 women) asymptomatic subjects were placed in 3 standardized thoraco-lumbar sitting postures (lumbo-pelvic, thoracic upright and slump) to investigate their influence on cervico-thoracic muscle activity and head/neck posture.There were significant differences in lumbar and thoracic curvatures in the 3 different sitting postures (P < 0.002). Slump sitting was associated with greater head/neck flexion, anterior translation of the head (P < 0.001) and increased muscle activity of cervical erector spinae (CES) compared to thoracic and lumbo-pelvic sitting (P = 0.001). Thoracic upright sitting showed increased muscle activity of thoracic erector spinae (TES) compared to slump and lumbo-pelvic postures (P = 0.015). Upper trapezius (UT) demonstrated no significant difference in muscle activation in the 3 sitting postures (P < 0.991). This study demonstrates that different sitting postures affect head/neck posture and cervico-thoracic muscle activity. It highlights the potential importance of thoraco-lumbar spine postural adjustment when training head/neck posture.     

Mechanical muscle and tendon properties of the plantar flexors are altered even in highly functional children with spastic cerebral palsy

BackgroundRecent ultrasound studies found increased passive muscle stiffness and no difference in tendon stiffness in highly impaired children and young adults with cerebral palsy. However, it is not known if muscle and tendon mechanical properties are already altered in highly functional children with cerebral palsy. Therefore, the purpose of this study was to compare the mechanical and material properties of the plantar flexors in highly functional children with cerebral palsy and typically developing children.MethodsBesides strength measurements, ultrasonography was used to assess gastrocnemius medialis and Achilles tendon elongation and stiffness, Achilles tendon stress, strain, and Young's modulus in twelve children with cerebral palsy (GMFCS levels I and II) and twelve typically developing peers during passive dorsiflexion rotations as well as maximum voluntary contractions.FindingsDespite no difference in ankle joint stiffness (P > 0.05) between groups, passive but not active Achilles tendon stiffness was significantly decreased (− 39%) and a tendency of increased passive muscle stiffness was observed even in highly functional children with cerebral palsy. However, material properties of the tendon were not altered. Maximum voluntary contraction showed reduced plantar flexor strength (− 48%) in the cerebral palsy group.InterpretationEven in children with mild spastic cerebral palsy, muscle and tendon mechanical properties are altered. However, it appears that the Achilles tendon stiffness is different only when low forces act on the tendon during passive movements. Although maximum voluntary force is already decreased, forces acting on the Achilles tendon during activity appear to be sufficient to maintain typical material properties.     

Clinical and radiographic features of spinal osteoarthritis predict long-term persistence and severity of back pain in older adults

BackgroundPatients with back pain can show one or more features of spinal osteoarthritis (OA), such as morning stiffness, limited or painful range of motion (ROM), and lumbar disc degeneration (LDD). However, it has not been investigated whether these features are prognostic of long-term back pain.ObjectivesThis study assessed whether spinal morning stiffness, ROM and LDD are prognostic factors for back pain after 1 year in older adults with back pain.MethodsThis prospective observational study (BACE cohort) included patients aged > 55 years visiting a general practitioner for a back-pain episode. Baseline patient-reported morning stiffness, physical examined ROM and radiographic LDD features (i.e., multilevel osteophytes and disc space narrowing) were analysed as potential prognostic factors in unadjusted and adjusted regression models with the outcomes of persistent back pain (yes/no) and back pain severity after 1-year follow-up.ResultsThis study included 543 patients with mean (SD) age 67 (8) years, 59% female, and 62% reporting back pain at 1-year follow-up. When studied in separate adjusted models, persistent back pain was associated with morning stiffness > 30 min (OR 3.0, 95%CI 1.3; 5.5), restricted lateroflexion (OR 1.8, 95%CI 1.0; 3.2), pain during rotation (OR = 1.7, 95%CI 1.0; 2.9), multilevel osteophytes (OR 2.4, 95%CI 1.4; 4.1), and multilevel disc space narrowing (OR 1.5, 95%CI 0.9; 2.4). When investigated in the same adjusted model, persistent back pain remained associated with only morning stiffness > 30 min (OR 2.4, 95%CI 1.0; 3.9), pain during rotation (OR 1.6, 95%CI 0.9; 2.8), and multilevel osteophytes (OR 2.1, 95%CI 1.2; 3.7). The same spinal OA-related features were associated with back pain severity.ConclusionsSpinal morning stiffness, painful rotation, and multilevel osteophytes are prognostic factors for persistent back pain and back pain severity after 1 year. Evaluating these clinical and radiographic features of spinal OA could help clinicians identify older patients who will experience long-term back pain.     

Immediate effects of a high-velocity spine manipulation in paraspinal muscles activity of nonspecific chronic low-back pain subjects

High-velocity spinal manipulation is commonly adopted for treating chronic low-back pain (CLBP) and has been associated with changes in muscle activity, but the evidence is controversial. The aim of this study was to analyse the immediate effects of high-velocity spine manipulation on paraspinal activity during flexion–extension trunk movements. Forty nonspecific CLBP patients were randomised into two groups, manipulation (n = 20) and control (n = 20). While the manipulation group received high-velocity spine manipulation at the L4-L5 level, the control group remained lying in the same position. EMG-related variables, perceived pain intensity (100 mm VAS) and finger-floor distance were collected before and after spinal manipulation at the L4-L5 level. EMG surface signals from the right and left paraspinal muscles (L5-S1 level) were acquired during trunk flexion–extension cycles. EMG activity during the static relaxation phase was significantly reduced following intervention for the manipulation group but not for the control group. The extension-phase EMG activity was also reduced after manipulation, but the flexion-phase EMG levels remained unchanged. Accordingly, the percent changes in FRR and ERR were significantly larger for the manipulation group compared to the control. The results suggest that a high-velocity spinal manipulation is able to acutely reduce abnormal EMG activity during the full-flexion static phase and activation during the extension phase.     

Effects of hip and trunk muscle strengthening on hip function and lower limb kinematics during step-down task

BackgroundStrengthening of the hip and trunk muscles has the potential to change lower limb kinematic patterns, such as excessive hip medial rotation and adduction during weight-bearing tasks. This study aimed to investigate the effect of hip and trunk muscles strengthening on hip muscle performance, hip passive properties, and lower limb kinematics during step-down task in women.MethodsThirty-four young women who demonstrated dynamic knee valgus during step-down were divided into two groups. The experimental group underwent three weekly sessions of strengthening exercises for eight weeks, and the control group continued their usual activities. The following evaluations were carried out: (a) isokinetic maximum concentric and eccentric work of hip lateral rotators, (b) isokinetic hip passive torque of lateral rotation and resting transverse plane position, and (c) three-dimensional kinematics of the lower limb during step-down.FindingsThe strengthening program increased concentric (P < 0.001) and eccentric (P < 0.001) work of hip lateral rotators, and changed hip resting position toward lateral rotation (P < 0.001). The intervention did not significantly change hip passive torque (P = 0.089, main effect). The program reduced hip (P = 0.002), thigh (P = 0.024) and shank (P = 0.005) adduction during step-down task. Hip, thigh and knee kinematics in transverse plane and foot kinematics in frontal plane did not significantly modify after intervention (P ≥ 0.069, main effect).InterpretationHip and trunk strengthening reduced lower limb adduction during step-down. The changes in hip maximum work and resting position may have contributed to the observed kinematic effects.     

Dance for Parkinson’s—The effects on whole body co-ordination during turning around

ObjectiveTo investigate the effects of ballroom and Latin American dancing classes on turning in people with Parkinson’s.DesignThis study employed a randomised, controlled, experimental design.SettingDance classes were performed in a community dance centre in Southern England and all assessments took place a gait laboratory.ParticipantsTwenty-seven people with mild-moderate Parkinson’s participated.InterventionParticipants were randomly allocated to receive either 20, 1-h dancing classes over 10 weeks (n = 15), or a ‘usual care’ control group (n = 12).Main outcome measureTwelve, 180° on-the-spot turns to the predicted/un-predicted and preferred/un-preferred direction were analysed for each participant, using 3-dimensional motion analysis before and after the intervention period, alongside clinical measures.ResultsMovement of the head, pelvis, and feet during turning in people with Parkinson’s are affected by dancing with tighter coupling of body segments. Significant 4-way interactions between the groups, over time and turn style, with longer latency of the head (p = 0.008) and greater rotation in the pelvis (p = 0.036), alongside a trend of slower movement of the first (p = 0.063) and second (p = 0.081) foot in controls were shown, with minimal change in dancers. All interactions were affected by the type of turn. No significant differences were found in the centre of mass displacement, turn time or clinical measures.ConclusionThose who danced were better able to coordinate their axial and perpendicular segments and surprisingly became more ‘en bloc’ in their turning behaviour, suggesting this may be a beneficial adaptation, rather than a maladaptive result of Parkinson’s, as previously suggested.     

Kinetics and kinematics after the Bridle procedure for treatment of traumatic foot drop

BackgroundThe Bridle procedure restores active ankle dorsiflexion through a tri-tendon anastomosis of the tibialis posterior, transferred to the dorsum of the foot, with the peroneus longus and tibialis anterior tendon. Inter-segmental foot motion after the Bridle procedure has not been measured. The purpose of this study is to report kinetic and kinematic variables during walking and heel rise in patients after the Bridle procedure.Methods18 Bridle and 10 control participants were studied. Walking and heel rise kinetic and kinematic variables were collected and compared using an ANOVA.FindingsDuring walking the Bridle group, compared with controls, had reduced ankle power at push-off [2.3 (SD 0.7) W/kg, 3.4 (SD 0.6) W/kg, respectively, P < .01], less hallux extension during swing [? 13 (SD 7)°, 15 (SD 6)°, respectively, P < .01] and slightly less ankle dorsiflexion during swing [6 (SD 4)°, 9 (SD 2)°, respectively, P = .03]. During heel rise the Bridle group had 4 (SD 6)° of forefoot on hindfoot dorsiflexion compared to 8 (SD 3)° of plantarflexion in the controls (P < .01).InterpretationThis study provides evidence that the Bridle procedure restores the majority of dorsiflexion motion during swing. However, plantarflexor function during push-off and hallux extension during swing were reduced during walking in the Bridle group. Abnormal mid-tarsal joint motion, forefoot on hindfoot dorsiflexion instead of plantarflexion, was identified in the Bridle group during the more challenging heel rise task. Intervention after the Bridle procedure must maximize ankle plantarflexor function and midfoot motion should be examined during challenging tasks.     

Assessment of the Sheffield Support Snood,an innovative cervical orthosis designed for people affected by neck muscle weakness

BackgroundThis study aimed at quantifying the biomechanical features of the Sheffield Support Snood, a cervical orthosis specifically designed for patients with neck muscle weakness. The orthosis is designed to be adaptable to a patient’s level of functional limitation using adjustable removable supports, which contribute support and restrict movement only in desired anatomical planes.MethodsThe snood was evaluated along with two commercially available orthoses, the Vista and Headmaster, in a series of flexion, extension, axial-rotation and lateral flexion movements. Characterization was performed with twelve healthy participants with and without the orthoses. Two inertial-magneto sensors, placed on the forehead and sternum, were used to quantify the neck’s range of motion.FindingsIn its less supportive configuration, the snood was effective in limiting movements to the desired planes, preserving free movement in other planes. The Headmaster was only effective in limiting flexion. The range of motion achieved with the snood in its rigid configuration was equivalent (P > 0.05, effect size < 0.4) to that achieved with the Vista, both in trials performed reaching the maximum amplitude (range of motion reduction: 25%–34% vs 24%–47%) and at maximum speed (range of motion reduction: 24%–29% vs 25%–43%).InterpretationThe Sheffield Support Snood is effectively adaptable to different tasks and, in its most supportive configuration, offers a support comparable to the Vista, but providing a less bulky structure. The chosen method is suitable for the assessment of range of motions while wearing neck orthoses and is easily translatable in a clinical context.     

Mid-term functional outcome of a total arthroplasty of the first metatarsophalangeal joint

BackgroundArthroplasty of the first metatarsophalangeal joint is an alternative treatment option for end-stage hallux rigidus to the current gold standard of arthrodesis. The aim of this study was to investigate the mid-term functional outcome of an anatomically shaped prosthesis for the first metatarsophalangeal joint using pedobarography.MethodsTen patients (12 affected feet; age at surgery: 62.1 (SD: 7.2) years) were investigated preoperatively and 52 (SD: 3) months postoperatively using pedobarography (EMED, novel GmbH, Munich, Germany). Two patients were excluded at follow-up because their prosthesis was converted to an arthrodesis. Peak force and plantar pressure under the five metatarsal heads and the hallux were analyzed and correlated with the clinical outcome (pain, American Orthopaedic Foot and Ankle Society forefoot score and radiographic maximum first metatarsophalangeal dorsiflexion). Differences between pre- and postoperative data were analyzed using paired t-tests (alpha = 0.05).FindingsPostoperatively, forefoot peak forces under the fourth (+ 40.9%; P = 0.018) and fifth metatarsal (+ 54.9%; P = 0.037) and plantar pressures under the fifth metatarsal (+ 38.7%; P = 0.027) increased significantly, while peak plantar pressures and forces under the hindfoot, medial forefoot and hallux did not change. While maximum passive dorsiflexion was not significantly greater at the 4-year follow-up compared to preoperatively, overall greater passive dorsiflexion was associated with higher first metatarsal peak pressure.InterpretationDespite of patients reporting less pain, the functional results indicate an altered and potentially non-physiological postoperative gait pattern with a lateralization of the load during walking, especially in patients with limited passive dorsiflexion.