The effect of bracing on patellofemoral joint stress during free and fast walking

BACKGROUND: Although several studies have demonstrated decreases in patellofemoral pain (PFP) with the application of bracing, the mechanism by which bracing reduces symptoms has not been elucidated. HYPOTHESIS: Individuals who responded favorably to bracing will exhibit decreased patellofemoral stress during level walking. STUDY DESIGN: Repeated measures, cross-sectional. METHODS: Fifteen subjects with a diagnosis of PFP completed two phases of data collection: 1) MRI assessment of patellofemoral contact area and 2) gait analysis. Data were obtained under braced and nonbraced conditions. Variables obtained from both data collection sessions were used as input variables into a mathematical model to quantify patellofemoral stress. RESULTS: Subjects reported a 56% reduction in pain following bracing. Bracing significantly reduced peak stress during free and fast walking (17% and 27%, respectively). The decrease in stress was the result of increased contact area as patellofemoral joint reaction forces were increased following bracing. CONCLUSION: Bracing resulted in a larger increase in patellofemoral contact area than the increase in joint reaction force, resulting in a decrease in joint stress. Clinical Relevance: The results of this study suggest a possible mechanism by which bracing may be effective in reducing PFP and provides experimental support for the use of this treatment method.     

Relationship between peripheral airway dysfunction, airway obstruction, and neutrophilic inflammation in COPD

BACKGROUND: Considerable research has been conducted into the nature of airway inflammation in chronic obstructive pulmonary disease (COPD) but the relationship between proximal airways inflammation and both dynamic collapse of the peripheral airways and HRCT determined emphysema severity remains unknown. A number of research tools have been combined to study smokers with a range of COPD severities classified according to the GOLD criteria. METHODS: Sixty five subjects (11 healthy smokers, 44 smokers with stage 0-IV COPD, and 10 healthy non-smokers) were assessed using lung function testing and HRCT scanning to quantify emphysema and peripheral airway dysfunction and sputum induction to measure airway inflammation. RESULTS: Expiratory HRCT measurements and the expiratory/inspiratory mean lung density ratio (both indicators of peripheral airway dysfunction) correlated more closely in smokers with the severity of airflow obstruction (r = -0.64, p<0.001) than did inspiratory HRCT measurements (which reflect emphysema severity; r = -0.45, p<0.01). Raised sputum neutrophil counts also correlated strongly in smokers with HRCT indicators of peripheral airway dysfunction (r = 0.55, p<0.001) but did not correlate with HRCT indicators of the severity of emphysema. CONCLUSIONS: This study suggests that peripheral airway dysfunction, assessed by expiratory HRCT measurements, is a determinant of COPD severity. Airway neutrophilia, a central feature of COPD, is closely associated with the severity of peripheral airway dysfunction in COPD but is not related to the overall severity of emphysema as measured by HRCT.     

Relationship between static mobility of the first ray and first ray, midfoot, and hindfoot motion during gait

The relationship between a static measure of dorsal first ray mobility and dynamic motion of the first ray, midfoot, and hindfoot during the stance phase of walking was investigated in healthy, asymptomatic subjects who represented the spectrum of static flexibility. Static first ray mobility of 15 subjects was measured by a load cell device and ranged from stiff (3.1 mm) to lax (8.0 mm). Using three-dimensional motion analysis, mean first ray dorsiflexion/eversion and mid-/hindfoot eversion peak motion, time-to-peak, and eversion excursion were evaluated. Subjects with greater static dorsal mobility of the first ray demonstrated significantly greater time-to-peak hindfoot eversion and eversion excursion (p <.01), and midfoot peak eversion and eversion excursion (p <.01). No significant association was found between static first ray mobility and first ray motion during gait. This research provides evidence that the dynamic response of the foot may modulate the consequences of first ray mobility and that compensory strategies are most effective when static measures of dorsal mobility are most extreme.     

Fluid shear in viscous fibronectin gels allows aggregation of fibrous materials for CNS tissue engineering

Fibronectin (Fn) materials prepared from human plasma have been used in various forms as substrates for tissue engineering. Such purposes require that the soluble protein aggregates into insoluble fibrous structures which encourage the attachment and migration of cells. The method of aggregation due to mechanical shear was investigated by applying fluid shear forces directly to a viscous solution of Fn. Structural analysis revealed that mechanical shear resulted in the formation of an orientated fibrous protein material that was less soluble than its non-sheared counterpart. The suitability of this shear aggregated Fn material for CNS repair purposes was assessed in vitro where it supported the growth of fibroblasts, S100 immunoreactive Schwann cells and GFAP immunoreactive astrocytes. Implantation of the shear aggregated Fn material into a rat model of spinal cord injury provided a permissive environment for axonal growth. This was extended using an impermeable coating to improve orientation and straightness of axonal growth.     

Cervical presentations of thymic anomalies in children

OBJECTIVE: To better define the clinical manifestations, radiologic imaging and the surgical management of cervical thymic lesions in children. STUDY DESIGN: Multi-center retrospective case review. METHODS: The charts of all children with pathologically confirmed thymic lesions at six children's hospitals (1990-2002) were reviewed for demographics, physical findings, X-ray findings, operative outcomes and pathology. RESULTS: There were a total of 15 children, 2 of whom had ectopic cervical thymus and 13 who had thymic cysts. They ranged in age from 1 month to 18 years. Thymic lesions were more common in males. Ectopic cervical thymus was best defined by MRI whereas thymic cyst had a more consistent appearance on CT. All children had successful surgical resection with no recorded complications or recurrences. CONCLUSIONS: Cervical thymic lesions are rare. Ectopic cervical thymus tends to be found primarily in infants whereas thymic cysts occur in a wider age range. Radiologic imaging is important but is not histologically specific. Definitive diagnosis and cure requires complete surgical excision.     

Ambulatory powered intracapsular tonsillectomy and adenoidectomy in children younger than 3 years

OBJECTIVES: (1) To assess the safety and efficacy of outpatient intracapsular tonsillectomy, which has been recently described as a less invasive means of treating obstructive tonsillar hypertrophy, in children younger than 3 years; and (2) to challenge the standard dictum that children younger than 3 years should be admitted to the hospital after tonsil and adenoid surgery. DESIGN: Retrospective cohort study via medical chart review and telephone interview. SETTING: Pediatric otolaryngology group practice with academic affiliation.Patients Children with symptomatic tonsillar and adenoid hypertrophy (n = 226) who underwent microdebrider-assisted intracapsular tonsillectomy between September 1, 2000, and October 1, 2002. METHODS: Comparison of study group (children <3 years old, n = 38; mean age, 30.3 months; 20 boys and 18 girls) with control group (children > or =3 years, n = 188), measuring pain, oral intake, analgesic requirements, complications, need for readmission, and relief of symptoms. RESULTS: There were no statistically significant differences in pain, oral intake, or analgesic requirements. All children, regardless of age, were discharged home within 4 hours of surgery. No child in either group required readmission, and there were no complications related to the time of discharge. Younger children experience equivalent symptomatic improvement. CONCLUSION: Children younger than 3 years may undergo intracapsular tonsillectomy as outpatients without sacrificing safety or efficacy.     

A randomised controlled trial of standing programme on bone mineral density in non-ambulant children with cerebral palsy

Background: Severely disabled children with cerebral palsy (CP) are prone to low trauma fractures, which are associated with reduced bone mineral density. Aims: To determine whether participation in 50% longer periods of standing (in either upright or semi-prone standing frames) would lead to an increase in the vertebral and proximal tibial volumetric trabecular bone mineral density (vTBMD) of non-ambulant children with CP. Methods: A heterogeneous group of 26 pre-pubertal children with CP (14 boys, 12 girls; age 4.3–10.8 years) participated in this randomised controlled trial. Subjects were matched into pairs using baseline vertebral vTBMD standard deviation scores. Children within the pairs were randomly allocated to either intervention (50% increase in the regular standing duration) or control (no increase in the regular standing duration) groups. Pre- and post-trial vertebral and proximal tibial vTBMD was measured by quantitative computed tomography (QCT). Results: The median standing duration was 80.5% (9.5–102%) and 140.6% (108.7–152.2%) of the baseline standing duration in the control group and intervention group respectively. The mean vertebral vTBMD in the intervention group showed an increase of 8.16 mg/cm³ representing a 6% mean increase in vertebral vTBMD. No change was observed in the mean proximal tibial vTBMD. Conclusion: A longer period of standing in non-ambulant children with CP improves vertebral but not proximal tibial vTBMD. Such an intervention might reduce the risk of vertebral fractures but is unlikely to reduce the risk of lower limb fractures in children with CP.