Biomedical subjects

D Rosenbaum

Publications and source records attributed to D Rosenbaum.

At least 73 records · Page 4Linked to original sources

PubMed1996

Calcaneal fractures cause a lateral load shift in Chopart joint contact stress and plantar pressure pattern in vitro.

In order to evaluate the effects of the anatomical changes after calcaneal fractures on joint loading characteristics we investigated the effects of simulated calcaneal fractures on intra-articular loading in the Chopart joint and on plantar pressure patterns in vitro. Five fresh-frozen lower leg specimens were axially loaded with 500 N in three positions: neutral, 10 degrees plantarflexion and 10 degrees dorsiflexion. The loading characteristics were determined before and after creating a tongue-type fracture by osteotomy. Plantar loading patterns were measured with a capacitive pressure distribution platform. Intra-articular contact areas and pressures were recorded on pressure sensitive film introduced into the talonavicular and calcaneocuboid joint. Increased loading in the calcaneocuboid joint (+25%,p = 0.005) and decreased loading in the talonavicular joint (-16%,p = 0.01) corresponded to increased loading of the lateral aspects of the plantar surface. These findings were independent of the foot position. The results suggest that the effects of increased lateral foot loading which have been observed in calcaneal fracture patients (Rosenbaum et al., Clin. Biomech. 10, 345-351, 1995) are caused by changes in joint kinematics and do not appear to result from a protective gait pattern established after the injury.

Adult↗

PubMed1996

[Functional deficits of the foot after calcaneus fracture].

The present study investigated the clinical and functional outcome of calcaneal fractures. 14 patients were evaluated at a mean follow-up of 52 months. Two groups, group A with good and group B with poor calcaneal restoration were distinguished by Böhler's angle. Ten normal subjects were used for comparison. Clinical results were evaluated with a questionnaire, radiography and range of motion measurements. Plantar pressure patterns were recorded with a capacitive pressure distribution platform. A comparison of the injured and healthy foot of all patients revealed a load shift towards lateral foot regions. A comparison of the patient groups with the controls did not reveal more pronounced changes in the poorly restored group. The results demonstrate that a disturbance of foot function persists even after long healing.

Adult↗

PubMed1996

[Functional disorders of the foot after tenodeses: is the method still currently acceptable?].

On the basis of biomechanical and clinical studies, this article discusses the relevance of tenodesis in the operative treatment of chronic lateral ankle instability. Considering the experimental results, it is evident that any tenodesis leads to restriction of inversion according to the course and the tightness of the graft. It has been shown that the lateral peroneal reconstruction has a negative influence on the kinematic coupling of the ankle joint complex. The data of the clinical studies reflect the biomechanical results. Despite a high rate of satisfaction, up to 50% of the patients reveal a restriction of inversion. Some authors, particularly those who report on a 10-year follow-up, showed that the degree of arthrosis increased and that deterioration of the clinical result occurred over the time. The measurement of plantar pressure distribution during gait proved the alteration of foot biomechanics. The biomechanical and clinical data available on tenodesis and the good results of the anatomical repair suggest that tenodesis is presently only the method of last choice.

Ankle Injuries↗

PubMed1996

Tenodesis versus carbon fiber repair of ankle ligaments: a clinical comparison.

To compare the clinical and functional outcomes after using different reconstruction methods for chronic ankle instability, the authors followed 2 groups of patients after 69 and 72 months, respectively. Thirty patients (mean age, 28; range, 23-39 years) were treated with modified Evans tenodesis. Twenty-three patients (mean age, 32.2; range, 22-39 years) underwent total replacement of the lateral ankle ligaments by carbon fibers. The protocol of the retrospective study included a questionnaire, clinical examination, radiographic stress diagnostics, and gait analysis with use of the EMED-SF system. Dorsiflexion and inversion were significantly restricted after tenodesis in contrast to the carbon fiber replacement. Although radiographic stability was improved after surgery for both groups, progress of the arthrosis could not be stopped. After tenodesis, the measurement of plantar pressure distribution revealed a 20% increase of midfoot loading as compared with the opposite foot, whereas symmetrical loading of both feet was found after carbon fiber replacement. Additionally, the tenodesis feet had a significantly increased loading of the medial side of the foot. It was concluded that tenodesis and anatomic reconstruction of ankle ligaments lead to subjectively similar results. Foot function and range of motion, however, were less influenced after anatomic repair.

Adult↗

PubMed1996

Early, full weightbearing with flexible fixation delays fracture healing.

Secondary fracture healing is known to be accelerated by the process of periosteal callus formation that can be induced by flexible fracture fixation in connection with loading of the injured extremity. The purpose of this study was to compare the healing of experimental fractures of long bones in sheep under early weightbearing with that of fractures under delayed, steadily increasing weightbearing. Differences in the quality of fracture healing were described by biomechanical (rigidity of fracture, indentation stiffness of callus) and histologic methods. Prevention from early, full weightbearing resulted in a higher flexural rigidity of the fracture, an increased mechanical stiffness of the callus tissue, and an enhanced bone formation at the healing front. Although early loading of a fresh fracture initiated an enormous amount of periosteal callus, the healing of the osteotomy was significantly delayed, and the quality of the newly formed tissue was reduced as compared with fractures with a reduced loading situation. A reduction of load transfer by delaying full weightbearing is advantageous for the healing of fractures stabilized with flexible fixation systems.

Animals↗

PubMed1996

Prevalence rates and correlates of psychiatric disorders among preschool children.

OBJECTIVE: To determine the prevalence and correlates of psychiatric disorders among preschool children in a primary care pediatric sample. METHOD: In a two-stage design, 3,860 preschool children were screened; 510 received fuller evaluations. RESULTS: For quantitative assessment of disorder (> or = 90th percentile), prevalence of behavior problems was 8.3%. "Probable" occurrence of an Axis I DSM-III-R disorder was 21.4% (9.1%, severe). Logistic regression analyses indicated significant demographic correlates for quantitative outcomes (older age, minority status, male sex, low socio-economic status, father absence, small family size) but not for DSM-III-R diagnoses. Maternal and family characteristics were generally not significant. Child correlates included activity level, timidity, persistence, and IQ. CONCLUSIONS: Overall prevalence of disorder was consistent with rates for older children; correlates varied by approach used for classification.

Age Factors↗

PubMed1996

Association of HLA class II alleles in patients with juvenile myoclonic epilepsy compared with patients with other forms of adolescent-onset generalized epilepsy.

Reports have suggested an association of juvenile myoclonic epilepsy (JME) with an HLA-DR allele. We examined the HLA-DR and DQ frequencies in two populations of epilepsy patients: (1) JME patients and (2) patients with other forms of adolescent-onset, idiopathic generalized epilepsy (IGE). We did DNA-based HLA typing on 24 JME patients and 24 patients with non-JME forms of adolescent-onset IGE, forms that are clinically similar to JME. In typing the HLA region, we paid particular attention to the alleles contributing to the HLA-DR13 type and also to the DQB1 locus alleles that are in linkage disequilibrium with the alleles that comprise the DR13 type. We also examined the HLA-AP locus, which is centromeric to the DR locus. The frequency of DR13 was significantly higher in JME compared with the non-JME patients. Nine JME patients, compared with two non-JME patients, carried that type (chi 2 = 5.78 [p < 0.017, 1 df]). The odds ratio was 6.6. Furthermore, the DQB1 alleles in linkage disequilibrium with the alleles contributing to the DR13 type were also more frequent in JME than in non-JME epilepsy patients. The chi 2 is highly significant (8.1, p < 0.005) with an odds ratio of 13.8. These results confirm that JME is an HLA-associated form of epilepsy. They also show that the JME locus probably lies within the HLA region, most likely between the HLA-DP and HLA-B loci. The association studies also confirm linkage results showing that JME is genetically different from some other IGEs and emphasize that careful diagnosis is critical to genetic studies of the epilepsies.

Adolescent↗

PubMed1996

[Foot stress simulator for biomechanical in vitro studies of lower leg segments].

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

Ankle Joint↗

PubMed1996

Long-term results of the modified Evans repair for chronic ankle instability.

We treated 19 patients for chronic ankle instability with a modified Evans procedure. All patients were evaluated after an average follow up of 128 months with detailed questionnaire, clinical examination, and stress radiographs. Although the subjective results were reported as 8 excellent, 7 good, and 4 fair, residual pain was reported by 11 patients. There was a significantly increased number of osteophytes in the treated ankle joint. Stress radiographs demonstrated significantly improved stability in the operated ankle joint. Range of motion was significantly reduced in hindfoot inversion. The results showed that the modified Evans procedure achieved sufficient joint stability at the expense of inversion range of motion. This reconstruction method apparently did not prevent the development of arthrosis.

Adult↗

PubMed1995

Measuring attending physician performance in a general medicine outpatient clinic.

OBJECTIVE: To determine which aspects of outpatient attending physician performance (e.g., clinical ability, teaching ability, interpersonal conduct) were measurable and separable by resident report. DESIGN: Self-administered evaluation form. SETTING: University internal medicine resident continuity clinic. PARTICIPANTS: All residents with their continuity clinic at the university hospital evaluated the two attendings who staffed their clinic for the academic years of 1990-1991, 1991-1992, and 1992-1993 (average of 85 total residents per year). The overall response rate was 74%. ANALYSIS: Exploratory analyses were conducted on a preliminary evaluation form in the first two years of the study (236 evaluations of 20 different clinic attendings) and confirmatory analyses using factor analysis and generalizability analysis were performed on the third year's data (142 evaluations of 15 different clinic attendings). Analysis of variance was used to evaluate factors associated with evaluation scores. RESULTS: Analyses demonstrated that the residents did not distinguish between the attendings' clinical and teaching abilities, resulting in a single four-item scale that was named the Clinical/Teaching Excellence Scale, measured on a five-point scale from poor to outstanding (Cronbach's alpha = 0.92). A large amount of the variance for this scale score was associated with attending identity (adjusted R2 = 46%). However, two alternative approaches to evaluating the performance of the attending (preference for him or her to the "average" attending and perceived impact of the attending on residents' clinical skills) did not provide useful information independent of the Clinical/Teaching Excellence Scale. The ratings of three separate conduct scales [availability in clinic (Availability Scale), treating residents and patients with respect (Respect Scale), and time efficiency in staffing cases (Slow Staffing Scale)] were separable from each other and from the rating of clinical/teaching excellence. For the Clinical/Teaching Excellent Scale, as few as four evaluations produced good interrater reliability and eight evaluations produced excellent reliability (reliability coefficients were 0.70 and 0.84, respectively). CONCLUSIONS: Although this evaluation instrument for measuring clinic attending performance must be considered preliminary, this study suggests that relatively few attending evaluations are required to reliably profile an individual attending's performance, that attending identity is associated with a large amount of the scale score variation, and that special issues of attending performance more relevant to the outpatient setting than the inpatient setting (availability in clinic and sensitivity to time efficiency) should be considered when evaluating clinic attending performance.

Analysis of Variance↗

PubMed1995

Long-term effects of hindfoot fractures evaluated by means of plantar pressure analyses.

The present study investigated the long-term effects of calcaneal fractures on the plantar pressure distribution during human gait. Fourteen patients participated in a follow-up study and were assigned to a group with good or poor calceneus restoration as indicated by normal or reduced Böhler's angle. Ten normal subjects with similar anthropometric characteristics were used for comparison. Gait analysis was performed by means of a capacitive pressure distribution platform. A comparison of the injured with the healthy foot of all patients revealed a statistically significant peak pressure decrease under medial areas of the foot (first metatarsal -24%) and an increase in lateral areas (midfoot +135%, fifth metatarsal +122%). This load shift towards a lateral loading indicates a persisting deviation of the gait pattern long after healing. Furthermore we investigated whether the success of the restoration of hindfoot geometry as reflected in Böhler's angle had an effect on the foot loading characteristics. Therefore we compared the gait patterns of the two patient groups with the normal subjects. However, the results did not reveal more abnormal pressure patterns in the poorly reduced group. RELEVANCE:--The restoration of the shape of the calcaneus with joint surface congruity and reconstruction of Böhler's angle appears generally accepted as a major aim in the treatment of calcaneal fractures. While this goal can usually be achieved by contemporary surgical techniques, the restoration of foot function under dynamic loading conditions is not guaranteed and should be assessed objectively. The investigation of the foot loading characteristics by means of plantar pressure measurements can be used to support the evaluation of the patient's recovery after trauma.

Journal Article↗

PubMed1995

The influence of stretching and warm-up exercises on Achilles tendon reflex activity.

The aim of this study was to investigate the acute effects of prior exercise (warm-up and stretching) on the electromyographic and force output of mechanically elicited triceps surae reflexes. Fifty male subjects performed eight reflex experiments under each of three successive conditions in one session: (1) no prior exercise, (2) after static stretching of the passive triceps surae (3 min) and (3) after a 10-min warm-up run on a treadmill. Tendon tap reflex force was elicited in the triceps surae of the right leg by means of a standardized reflex hammer and measured in a custom-built fixture. Electromyographic (EMG) signals were recorded with surface electrodes over the medial head of the gastrocnemius (G) and the soleus (S). Low coefficients of variation within subjects contrasted with high between-subject variations, indicating highly individual reflex characteristics. After stretching, reductions in the peak force (-5%; P < 0.05), the force rise rate (-8%; P < 0.01), the half relaxation rate (-5%; N.S.), the EMG amplitudes (G, -16%; S, -17%; P < 0.01) and integrals (G, -15%; S, -18%; P < 0.01), and an increase in EMG latencies (G, +3%; S, +1%; P < 0.01), were found compared with the values obtained without prior exercise. After running, the peak force reached the values obtained without prior exercise (-2%; N.S.), the force rise rate and half relaxation rate increased by 8 and 12%, respectively (P < 0.01), and the impulse (force-time integral; -12%), EMG amplitudes (G, -20%; S, -23%; P < 0.01), integrals (G, -18%; S, -23%; P < 0.01) and latencies (G, -1%; S, -2%; P < 0.01) decreased significantly. The changes in the force characteristics observed after the stretching treatment indicate improved muscle compliance that might reduce the risk of injury. On the other hand, the changes after the additional warm-up run had a more pronounced influence with regard to improved force development and a decreased EMG activity, which can be viewed as a performance-enhancing effect.

Achilles Tendon↗

PubMed1995

The genetics of idiopathic generalized epilepsies of adolescent onset: differences between juvenile myoclonic epilepsy and epilepsy with random grand mal and with awakening grand mal.

Both linkage and association studies provide strong evidence that a gene locus on chromosome 6 is involved in the expression of juvenile myoclonic epilepsy (JME), an adolescent-onset form of primary idiopathic generalized epilepsy (IGE). This epilepsy-related gene locus, designated EJM-1, may also influence the expression of other forms of IGE. We report here evidence that at least one form of epilepsy that is similar to JME--pure, adolescent-onset grand mal epilepsy in which the seizures occur at any time during waking--is not linked to the EJM-1 locus. However, we also have evidence that another form of pure, adolescent-onset grand mal that occurs on awakening is linked to the EJM-1 locus and may be genetically the same as JME. This work suggests that clinically similar epileptic syndromes may have different genetic bases and underscores the critical importance of careful clinical observations in studying the genetics of the epilepsies.

Adolescent↗

PubMed1995

Gait asymmetry following successful surgical treatment of ankle fractures in young adults.

Forty patients (mean age, 22.8 years) admitted for displaced ankle fracture were observed retrospectively to determine by clinical examination and measurement of plantar pressure distribution whether successful surgical treatment of ankle fractures led to gait symmetry, and whether intraindividual differences were related to fracture type and clinical outcome. The mean followup was 18.5 months (range, 12-36 months). The deviation of gait was quantified using a symmetry index of the total impulse. Using a clinical score, 6 patients had unsatisfactory results, and the remaining 34 had satisfactory results. The symmetry index of the good (-1.1%) and the poor results (-2.3%) decreased in the range of a healthy control group (-0.31%, n = 90), indicating that overall gait symmetry was achieved after trauma. The plantar pressure distribution showed significant load asymmetries. There was increased loading in the lateral forefoot of the injured leg in patients with good results and decreased pressure under the metatarsal heads of patients with bad results. Although those asymmetries were related neither to fracture type nor clinical outcome, the findings may illustrate compensation mechanisms that are used to regain gait symmetry after ankle alteration by trauma.

Adult↗

PubMed1995

[Clinical and roentgenologic 5 year follow-up of modified Evans-plasty in chronic lateral instability of the ankle joint].

Between 1984 and 1989, 108 patients who had chronic lateral instability of the ankle were treated with a modified Evans tenodesis, in which the anterior half of the peroneus brevis tendon was used for reconstruction. Follow up was possible by questionnaire in 75 patients and by clinical examination in 46, after 29-122 months (mean 68 months). Subjectively excellent or good results were achieved in 62 patients (82.6%) while 9 (12%) had fair results and 4 (5.4%) a poor outcome. Pain during physical activity was reported by 27 patients (35%), loss of inversion by 34 (45%) and slight instability by 31 (41%). The X-ray films at follow-up revealed more signs of arthrosis than had been present preoperatively. The stress tests showed an anterior drawer of 7.8 mm preoperatively and 7.0 mm postoperatively (p = 0.03); talar tilt was improved from 7.7 degrees to 4.5 degrees (p < or = 0.01). The outcome reported by the patients and the objective results of the clinical and radiological examinations were at odds. Pain, instability and osteophyte formation after the operation were so frequent because the talus was not fixed when the Evans reconstruction was implemented. Therefore, we suggest that this method should not be used in patients with a high activity level.

Adult↗

PubMed1994

Interrater reliability of the DSM-III-R with preschool children.

Little attention has been paid to evaluating the use of DSM-III-R with preschool children. Children (N = 510) ages 2 to 5 years who were screened at the time of a pediatric visit were selected to participate in an evaluation which included questionnaires, a semistructured interview, developmental testing, and a play observation. Following the evaluation, two clinical child psychologists independently assigned DSM-III-R diagnoses. For each diagnostic category, kappa and Y coefficients were calculated; Y coefficients are less sensitive to base rates of disorders. For overall agreement, the weighted mean kappa (.61), and mean Y (.66) were moderately high. Overall agreement that the child had at least one of the disruptive disorders was substantial (kappa = .64; Y = .65); agreement that there was at least one of the emotional disorders was moderate for kappa (.54), but substantial for Y (.70). Kappa coefficients were higher for major categories of disorder than for specific disorders; however, Y coefficients did not show a decline for specific disorders. Interrater reliability of DSM-III-R appears to be similar for preschoolers and older children.

Adjustment Disorders↗

PubMed1994

Plantar pressure distribution patterns of young school children in comparison to adults.

Peak pressures and relative loads were determined under the feet of 125 children between 6 and 10 years of age. These results were compared with previously published data from 111 adults. A capacitive pressure distribution platform with a resolution of 2 sensors/cm2 was used for data collection during walking. As compared with the group of adults, the school children showed considerably lower peak pressures under all anatomical structures. Larger foot dimensions with respect to body weight result in reduced foot pressures for the children by distributing the ground reaction forces across larger contact areas. With increasing age, a medial load shift in the forefoot could be observed for the older children. Data analysis of the pressures under the midfoot revealed that the longitudinal foot arch development is almost complete before the age of 6. Contrary to the findings in adults, body weight was identified to be of major influence on the magnitude of the pressures under the feet of school children. No differences were found for the foot pressures between boys and girls.

Adult↗

PubMed1994

Gait pattern analysis after ankle ligament reconstruction (modified Evans procedure).

We followed 38 patients with chronic ankle instability treated by a modified Evans procedure. Evaluation at an average of 68 months follow-up included a standard clinical questionnaire and examination, radiological procedures, and gait analysis. Plantar pressure distribution measurements were recorded during walking and were compared with data from a group of normal subjects (N = 100). The subjective patient questionnaire revealed 87% good or excellent results, but residual pain was reported by 40% of the patients. The gait analysis indicated a significant increase in midfoot loading (22%) consistent with an observed restriction of inversion after surgery. However, the plantar pressure changes were not associated with poor clinical outcome. We cannot say whether these increased pressures will be associated with long-term outcome.

Adult↗