Kinematic classification of iliotibial band syndrome in runners.

Several inconsistent causative biomechanical factors are considered to be crucial in the occurrence of iliotibial band syndrome (ITBS). The focus of this study was on assessing differences in the kinematic characteristics between healthy runners [control group (CO)] and runners with ITBS in order to recommend treatment strategies to deal with this injury. Three-dimensional kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to gender, height and weight. After determining drop outs, the final population comprised 36 subjects (26 male and 10 female): 18 CO and 18 ITBS (13 male and five female, each). Kinematic evaluations indicate less hip adduction and frontal range of motion at the hip joint in runners with ITBS. Furthermore, maximum hip flexion velocity and maximum knee flexion velocity were lower in runners with ITBS. Lack of joint coordination, expressed as earlier hip flexion and a tendency toward earlier knee flexion, was found to be another discriminating variable in subjects with ITBS compared with CO subjects. We assume that an increase in range of motion at the hip joint, stretching of the hip abductors, as well as stretching the hamstrings, calf muscles and hip flexors will help treat ITBS.

A new approach to children's footwear based on foot type classification.

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.

Sex-related differences in foot shape.

The purpose of the study was to investigate sex-related differences in foot morphology. In total, 847 subjects were scanned using a 3-D-footscanner. Three different analysis methods were used: (1) comparisons were made for absolute foot measures within 250-270 mm foot length (FL); (2) and for averaged measures (% FL) across all sizes; (3) the feet were then classified using a cluster analysis. Within 250-270 mm FL, male feet were wider and higher (mean differences (MD) 1.3-5.9 mm). No relevant sex-related differences could be found in the comparison of averaged measures (MD 0.3-0.6% FL). Foot types were categorised into voluminous, flat-pointed and slender. Shorter feet were more often voluminous, longer feet were more likely to be narrow and flat. However, the definition of 'short' and 'long' was sex-related; thus, allometry of foot measures was different. For shoe design, measures should be derived for each size and sex separately. Different foot types should be considered to account for the variety in foot shape. Improper footwear can cause foot pain and deformity. Therefore, knowledge of sex-related differences in foot measures is important to assist proper shoe fit in both men and women. The present study supplements the field of knowledge within this context with recommendations for the manufacturing of shoes.

What are causes and treatment strategies for patellar-tendinopathy in female runners?

Patellar-tendinopathy (PT) is a common overuse injury in long distance runners, especially in women. Until today, no definite combinations of clinical, biomechanical, or training variables, or causative factors in the development of PT have been found. This study focused on assessing the differences in biomechanical characteristics between healthy runners (CO) and runners with PT only. We examined a total of 42 women. 21 CO and 21 PT. 3D kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to height and weight. After determining dropouts due to forefoot running, poor quality of data and lack of matching subjects in CO in terms of body height and weight, the final population comprised 24 subjects (CO=12, PT=12). Biomechanical evaluations indicate eccentric overloading of the quadriceps muscle group (knee extensors), increased pronation velocity as well as a lack of joint coordination as major etiological factors in the development of PT. We assume that eccentric strengthening of the knee extensors, as well as reduction of pronation velocity through orthotics, proper running shoes, and balance training will help treat and possibly prevent PT.

Foot morphology of normal, underweight and overweight children.

OBJECTIVE: Due to the fact that there is a global increase in obesity, knowledge about the impact of obesity on the development of a child's foot is of great importance for orthopaedic and paediatric physicians with regard to prevention, clinical treatment and management. Therefore, the purpose of this study was to investigate the influence of body mass on the development of a child's foot based on a foot type classification. METHODS: The feet of 1450 boys and 1437 girls aged 2-14 years were measured using a three-dimensional (3D) foot scanner (Pedus, Human Solutions Inc., Germany) in a bipedal upright position. Twelve relevant 3D foot measures were recorded, as well as the children's age, gender, height and mass. Factor analysis of principal components was used to obtain a smaller number of independent and standardized variables. The variables were used for cluster analysis to classify the children's feet. RESULTS: Five foot types were identified: flat, robust, slender, short and long feet. There were significant differences among foot types with respect to the children's body mass index. Normal weight children displayed an almost equal distribution of all foot types throughout childhood. Flat and robust feet were more common in overweight children, whereas underweight children showed more slender and long feet. CONCLUSION: The influence of excess, as well as deficient mass could be verified for the comprehensive foot morphology based on a foot type classification. Subsequently, foot discomfort as a result of various musculoskeletal disorders may develop. In turn, this might keep the children from being active and therefore reinforce the risk of developing obesity. However, there is still a lack of information regarding these relationships, which needs to be determined. This knowledge may help prevent orthopaedic foot problems and injuries.

Changes in plantar pressure distribution after Achilles tendon augmentation with flexor hallucis longus transfer.

BACKGROUND: Augmentation of the Achilles tendon with flexor hallucis longus is an established method to treat neglected ruptures and severe cases of chronic tendinopathy. After transfer of the muscle/tendon, good pain reduction and improved plantar flexion have been reported. To date, only one study has investigated the effect of FHL transfer on forefoot biomechanics. Theoretically, there should be a partial transfer of forefoot loading towards the lateral metatarsal heads during push-off, resulting in an asymmetric gait. METHODS: 13 patients were examined clinically and using pedobarography with a mean follow-up of 46 months (minimum 24) after Achilles tendon augmentation with flexor hallucis longus. Parameters of the forefoot were investigated to detect differences in pressure and force distribution, load transfer to other areas of the forefoot, and asymmetries compared to the non-operated leg. The results are discussed with regard to clinical relevance. FINDINGS: Clinically, there were no subjective or objective gait asymmetries. All patients were free of pain and without restrictions during normal walking. In general, pedobarography showed an unloading of the first toe with a load transfer to the metatarsal heads on the operated side. All results featured high inter-subject and within-subject variability. INTERPRETATION: Due to the high within-subject variability, there is inconsistency within the results making interpretation difficult. However, the results confirm the hypothesis that unloading of the first toe during push-off and an asymmetrical loading pattern can be measured after harvesting of the flexor hallucis longus. The clinical situation of the patients did not reflect a visible amount of gait asymmetry. Differences in loading patterns 2 years after flexor hallucis longus transfer for Achilles tendon augmentation appear to be well compensated.

Hip abductor weakness is not the cause for iliotibial band syndrome.

Muscular deficits in the hip abductors are presumed to be a major factor in the development of Iliotibial Band Syndrome in runners. No definite relationship between muscular weakness of the hip abductors and the development of Iliotibial Band Syndrome or different ratios between hip adduction to abduction have been reported so far. Isokinetic measurements were taken from 10 healthy runners and 10 runners with Iliotibial Band Syndrome. Primary outcome variables were concentric, eccentric, and isometric peak torque of the hip abductors and adductors at 30 degrees/s, and a concentric endurance quotient at the same angle velocity. Differences in muscle strength of the hip abductors between healthy (CO) and injured runners (ITBS) were not statistically significant in any of the muscle functions tested. Both groups showed the same strength differences between hip adduction and abduction, and increased strength in hip adduction. Weakness of hip abductors does not seem to play a role in the etiology of Iliotibial Band Syndrome in runners, since dynamic and static strength measurements did not differ between groups, and differences between hip abduction and adduction were the same. Strengthening of hip abductors seems to have little effect on the prevention of Iliotibial Band Syndrome in runners.

Effect of changing the weekly dose intensity of fractionated irradiation on local control of two human squamous cell carcinomas in nude mice.

PURPOSE: To compare the effect of fractionated irradiation with increasing, constant or decreasing weekly dose intensity on local tumour control. MATERIALS AND METHODS: Human squamous cell carcinomas, FaDu and GL, were grown in nude mice. Thirty fractions were applied under ambient conditions with increasing, constant or decreasing weekly dose intensity within a constant overall treatment time of 6 weeks. Dose intensity was changed every 2 weeks. Irradiations were terminated in some groups of animals after 20 fractions in 4 weeks. Endpoint was the tumour control dose 50% (TCD50) at day 120 (FaDu) or day 180 (GL) after end of treatment. RESULTS: In FaDu tumours the TCD50 value of 60 Gy (95% CI 56; 63) for fractionated irradiation with decreasing dose intensity, i.e. high initial doses, was slightly but significantly lower than the TCD50, of 68 (60; 81) after low initial doses (p=0.03). The TCD50 value of 62 Gy (57; 68) after constant doses was intermediate (constant vs increasing p =0.30; constant vs decreasing p=0.15). The higher efficacy of high initial doses in FaDu tumours was explained by local control occurring already during the course of irradiation. In GL tumours the TCD50 values were 52 Gy (43; 62) after high initial dose intensity, 50 Gy (43; 66) after constant doses, and 55 Gy (42; 89) after low initial dose intensity. These values were not statistically different (p-values 0.20-0.75). CONCLUSIONS: The data support the view that initial dose concentration during fractionated irradiation does not enhance radioresistance of FaDu and GL tumours, for instance by an earlier onset of clonogen repopulation.

[Limits and possibilities of 2D video analysis in evaluating physiological and pathological foot rolling motion in runners]. / Grenzen und Möglichkeiten der 2D-Videoanalyse in der Bewertung physiologischer und pathologischer Abrollvorgänge des Fusses bei Läufern.

Three-dimensional movements of the lower extremities in support phases are usually evaluated with the help of video analysis. This analysis is mainly done two-dimensionally in a frontal and sagittal plane. Usually, the temporal ankle of the achilles tendon respectively rear foot are analysed in the frontal plane, the knee and upper ankle angle in the sagittal plane, because their values are made responsible for different sport injuries. However, so far a correlation between different injuries and biomechanical parameters could not be proven. Often, small changes in 2D video data are discussed without considering the reliability of this method of measurement. It was the aim of this study to evaluate these parameters in 2D video analyses (2D-VA) which characterize the support phases of the foot. A second goal was to find out whether a connection between these angles and chronic achillodynia can then be sensibly proven. 32 male test persons consisting of a control group (KO, n = 14) without injuries and a group with chronic achillodynia (AD, n = 18), have been examined with the test/retest method in weekly intervals. The biomechanical running analysis was done with the help of 2D-VA in the frontal and sagittal plane on a treadmill at a speed of 80% of the individual anaerobic threshold with different shoes. The test/retest variability was for all measuring points not at all satisfying. Both groups showed big mean variations in both shoes and minimal differences in the measured angles. Because of the poor capability of reproduction of the 2D-VA for angles in the frontal plane this measuring method is only usable with restrictions for the evaluation of the support phase.

Recent progress on the role of Axl, a receptor tyrosine kinase, in malignant transformation of myeloid leukemias.

Receptor tyrosine kinases (RTK) play an important role in the signal transduction of normal and malignant cells. There are different families of RTKs which are mainly characterized by differences in the ligang-binding extracellular domains. Axl (or UFO/Ark) is the first member of a new class of RTK with two fibronectin type III domains and two immunoglobulin-like domains present at the extracellular domain. The axl-gene has been isolated by means of gene transfection studies using DNA of patients with chronic myelogeneous leukemia. For a previous and the present study, we used a sensitive reverse-transcriptase polymerase chain reaction assay to detect axl's mRNA in cells from normal and malignant hematopoietic tissue. Axl's mRNA expression was mainly detected in myelo-monocytic cells, whereas much weaker transcription was seen in lymphatic cells and in lymphatic leukemias. In normal bone marrow, axl was heavily transcribed in marrow stromal cells. Further, we analysed Axl protein expression using monoclonal antibody M50 in peripheral stem cell harvests; in most harvests, no co-expression of CD34 and Axl was detected. However, in one patient with AML in complete remission, Axl was co-expressed on 80% of the CD34-positive population. These data show that axl is preferentially expressed in monocytes and stromal cells. Furthermore, a fraction of CD34-positive progenitor cells may express Axl. The exact mechanism for transformation of myeloid progenitor cells through Axl, however, remains to be determined.

Effects of different beta-blockers on lipid metabolism in chronic therapy of hypertension.

The aim of this study was to evaluate the possible time-related effects of long-term monotherapy with different beta-blockers on plasma lipids in patients with essential hypertension. We studied 69 mild-moderate hypertensives, all males, aged 35-56 years belonging to the same working community. After 1-month placebo period, patients were assigned to receive propranolol 160 mg/day or atenolol 100 mg/day or bisoprolol 10 mg/day or mepindolol 10 mg/day. They were followed-up for 2 years. Blood pressure (BP), heart rate and blood samples for evaluation of total cholesterol (TC), LDL-cholesterol (LDL-C), triglycerides (TG) and HDL-cholesterol (HDL-C) were taken before and after placebo period and every 6 months from the beginning of the active treatment. All beta-blockers caused similar reduction in BP values which persisted throughout the study. None of the beta-blockers significantly affected TC and LDL-C. Propranolol caused the most pronounced changes in TG (+35-43%) and in HDL-C (-36-44%). Atenolol had the same qualitative effects but to a lesser extent (TG: +26-30%; HDL: -15-25%). Bisoprolol has more beta 1-selective than atenolol, and mepindolol, non-selective with ISA, increased TG (+15-28% and +13-23%) but did not significantly affect HDL-C. Consequently, HDL-C and TG changes appeared to be related to the ancillary properties of the different beta-blockers and, in a lesser degree, to the duration of therapy.