Minor change in the sulcus angle during the first six years of life: a prospective study of the femoral trochlea development in dysplastic and normal knees.

PURPOSE: The aetiology of femoral trochlear dysplasia is unknown. The aim of this prospective cohort study was to describe trochlear development in a newborn population during the first six years of life. METHODS: In an earlier study, the femoral trochlea was examined by ultrasound in 174 newborns. A dysplastic trochlea was defined with a sulcus angle (SA) above 159°. Two groups were defined, one group of 15 knees with SA > 159° (dysplastic group), and one group of 101 knees with SA < 159° (non-dysplastic group). In the present follow-up study, the children were further examined at six, 18 and 72 months. RESULTS: There was a statistically significant difference in the SA between the dysplastic and the non-dysplastic group at all follow-ups (p < 0.001). A small but statistically significant change in the SA between 0 to 72 months was detected for the dysplastic knees (p = 0.032) and for the controls (p < 0.001). CONCLUSION: Only minor changes in the anatomy of the femoral trochlea from newborn to age six years were found. A dysplastic trochlea at birth remains shallow and the anatomy does not change from normal to dysplastic during the same time span. LEVEL OF EVIDENCE: II.

Remembered preoperative Quick disabilities of the arm, shoulder and hand (QuickDASH) scores.

The Quick disabilities of the arm, shoulder and hand (QuickDASH) patient-reported outcome measure is frequently used to assess disabilities and symptoms of the upper extremity. This study compares real preoperative QuickDASH scores and remembered preoperative QuickDASH scores. Remembered preoperative QuickDASH scores were obtained 45 months (39-67) after surgery. Patient material consisted of 160 patients operated for Dupuytren's contracture, carpal tunnel syndrome, thumb basal joint arthrosis, and shoulder pain. All patients had completed QuickDASH questionnaires before surgery. Paired T-tests, linear mixed models, and limits of agreement were used for analyses. There was a significant difference between remembered and real preoperative scores (mean 7.6, SD 15.6; SEM 1.2). Neither diagnosis, age, gender, nor time between surgery and review influenced the difference significantly. A linear mixed model was constructed to investigate the ability to retrospectively predict preoperative QuickDASH scores. Remembered preoperative QuickDASH cannot be used in individual patients because of the high inaccuracy. LEVEL OF EVIDENCE: III.

The repeatability of oVEMP in response to low-frequency vibration against the vertex and forehead.

BACKGROUND: The measurement of ocular Vestibular Evoked Myogenic Potentials (oVEMP) is a novel method for investigating vestibular function. Stimulus and recording techniques vary in the literature. A standardized test procedure is desirable in order to ensure repeatable results. OBJECTIVE: To investigate the magnitude and repeatability of the asymmetry ratio (AR) of oVEMPs in response to low-frequency bone conducted vibration (BCV) applied to the forehead and vertex in a healthy population. METHODS: 20 healthy subjects were tested three times by stimulating with 125 Hz BCV at the forehead and the vertex. The first two tests were performed with the subject remaining in the examining room and the electrodes in place. After a short break, a third test was performed with a new set of electrodes. The AR was calculated for each test based on the evoked oVEMPs responses from the left and the right side. The AR magnitude, variance and repeatability coefficients were evaluated to determine which of the two stimulus sites is best suited in clinical use. RESULTS: Stimulation at the forehead resulted in a statistically significant lower median AR compared to the vertex. The forehead had lower repeatability coefficients, and statistically significantly lower variances. CONCLUSIONS: This study indicates that the forehead is a better stimulation site than the vertex for low-frequency BCV in clinical use.

Ocular vestibular-evoked myogenic potentials (oVEMPs) in response to bone-conducted vertex vibration.

OBJECTIVE: To investigate low-frequency vertex bone-conducted (BC) vibration for evoking ocular vestibular myogenic potentials (oVEMPs) and its ability to discriminate between lesioned and healthy ears. METHODS: oVEMPs were analysed in response to 125-Hz single cycle vertex BC vibration in healthy subjects (n=50) and in patients with severe unilateral vestibular loss (n=10). Both positive and negative initial stimulus motions were used. RESULTS: In most healthy subjects, vertex BC vibration oVEMPs was successfully and symmetrically evoked from both ears. The response was dependent on the direction of the stimulus motion. The latency was shorter with negative initial stimulus motion; however, a positive initial stimulus motion generated somewhat larger amplitudes. Furthermore, there was no significant response from lesioned ears, whereas oVEMPs from the patients' healthy ears were similar to the responses in healthy subjects. CONCLUSION: The oVEMP low-frequency BC response was dependent on the direction of the initial stimulus motion. Testing oVEMPs in response to low-frequency vertex vibration can discriminate patients with unilateral vestibular function loss from healthy controls. SIGNIFICANCE: Low-frequency vertex BC vibration oVEMPs should be considered a possible clinical screening test to evaluate vestibular function.

Statistical consequences of using bone mineral density to pair cadaver femurs in comparative ex vivo hip fracture studies.

OBJECTIVE: In ex vivo hip fracture studies femoral pairs are split to create two comparable test groups. When more than two groups are required, or if paired femurs cannot be obtained, group allocation according to bone mineral density (BMD) is sometimes performed. In this statistical experiment we explore how this affects experimental results and sample size considerations. METHODS: In a hip fracture experiment, nine pairs of human cadaver femurs were tested in a paired study design. The femurs were then re-matched according to BMD, creating two new test groups. Intra-pair variance and paired correlations in fixation stability were calculated. A hypothetical power analysis was then performed to explore the required sample size for the two types of group allocation. RESULTS: The standard deviation (sd) of the mean paired difference in fixation stability increased from 2 mm in donor pairs to 5 mm in BMD-matched pairs. Intra-pair correlation was 0.953 (Pearson's r) in donor pairs and non-significant at -0.134 (Pearson's r) in BMD-matched pairs. Required sample size to achieve a statistical power of 0.8 increased from ten pairs using donor pairs to 54 pairs using BMD-matched pairs. CONCLUSION: BMD cannot be used to create comparable test groups unless sample size is increased substantially and paired statistics are no longer valid. Cite this article: Bone Joint Res 2014;3:317-20.

One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise.

AIM: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO(2)max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. METHODS: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO(2) during cycling and one-legged cycling was tested before and after training, while VO(2) of the trained leg (TL) and control leg (CL) during cycling was determined after training. RESULTS: VO(2) max for cycling was unaffected by training, although one-legged VO(2) max became 6.7 (2.3)% (mean ± SE) larger with TL than with CL. Also TL citrate synthase activity was higher [30 (12)%; P < 0.05]. With the two legs working at precisely the same power during cycling at high intensity (n = 8), leg oxygen uptake was 21 (8)% larger for TL than for CL (P < 0.05) with oxygen extraction being 3.5 (1.1)% higher (P < 0.05) and leg blood flow tended to be higher by 16.0 (7.0)% (P = 0.06). CONCLUSION: That enhanced VO(2) max for the trained leg had no implication for cycling VO(2) max supports that there is a central limitation to VO(2) max during whole-body exercise. However, the metabolic balance between the legs was changed during high-intensity exercise as oxygen delivery and oxygen extraction were higher in the trained leg, suggesting that endurance training ameliorates blunting of leg blood flow and oxygen uptake during whole-body exercise.

In vitro testing of the deformation pattern and initial stability of a cementless stem coupled to an experimental femoral head, with increased offset and altered femoral neck angles.

The ability to vary femoral offset and neck angles in total hip arthroplasty increases the amount of flexibility in the mechanical reconstruction of the hip joint. The present study investigates the changes in strain pattern and bone-implant micromotion caused by increased femoral offset in combination with retroversion or reduced neck-shaft angle, made possible by a large experimental femoral head. A cementless femoral stem was inserted in 10 human cadaver femurs. Three femoral head configurations were tested: the standard situation, an increased offset combined with retroversion, and increased offset combined with reduced neck-shaft angle. The femurs were loaded in a hip simulator that was able to reproduce the conditions that correspond to one-legged stance and stair climbing. There was a statistically significant increase in strain for the experimental head at several strain gauge rosettes compared to the standard head. The largest significant increase in strain was 14.2 per cent on the anterior side of the femur. The largest mean total point motion was 44 microm in the distal coating area for the configuration with increased femoral offset and retroverted neck axis. The clinical relevance of the changes in strain distribution is uncertain. The femoral stem showed excellent initial stability for all test situations.

The rotation ratios method: a method to describe altered pelvic orientation in sequential radiographs.

BACKGROUND: A method to describe pelvic rotations between pairs of standard sequential pelvic anteroposterior radiographs based on a pelvic phantom is described in a former study. PURPOSE: To expand this method into clinical use based on clinical data. MATERIAL AND METHODS: Teardrop distances were measured on 262 pelvic radiographs from 46 patients in a clinical material using a computer program designed to perform measurements on digital radiographs. Anthropometric data recorded from 141 pelvises in an anatomical collection were employed in a computer program designed to simulate radiographs of virtual objects. Virtual rotations of the pelvises were carried out with 4653 virtual radiographs obtained. Virtual radiographic measures were analyzed. RESULTS: A statistically significant difference of 8 mm between mean teardrop distance in females (120 mm) and males (112 mm) was found in the clinical material. A set of formulas describing the relations between differences of two rotation ratios and pelvic rotations were derived. Four simple regression analyses were carried out with the use of virtual measures. Adjusted teardrop distances were implemented. CONCLUSION: A clinical method to describe pelvic rotations using standard pelvic radiographs was developed.

Pelvic rotations: a pelvic phantom study.

BACKGROUND: Radiographic measurements made on standard pelvic radiographs are commonly used in studying conditions related to the hip joints. Effects caused by variations in pelvic orientation may be a source of error in comparing measurements between sequential radiographs. PURPOSE: To define and characterize parameters able to measure rotational differences separately around two axes and altered radiographic focusing along two axes when sequential standard anteroposterior (AP) pelvic radiographs are compared. MATERIAL AND METHODS: A pelvic phantom was constructed based on direct three-dimensional measurements of five defined landmarks in a pelvic model. Two ratios, the vertical and transversal rotation ratios, were defined using radiographs of the phantom. The phantom was radiographed in 33 different orientations and with 16 different radiographic focuses using a specially constructed tilt table. On each radiograph, measurements were made and the two rotation ratios were calculated using a measurement program. RESULTS: Linear correlations between pelvic rotations around one axis and the corresponding rotation ratio were found with almost no influence of simultaneous rotation around the other axis. Also, linear correlations were found between altered radiographic focusing along one axis and the non-corresponding rotation ratio. CONCLUSION: Rotational differences around two axes or altered radiographic focusing along two axes can be measured independently. Effects caused by rotations cannot be distinguished from effects caused by altered radiographic focusing.

Validation of the rotation ratios method.

BACKGROUND: The rotation ratios method describes rotations between pairs of sequential pelvic radiographs. The method seems promising but has not been validated. PURPOSE: To validate the accuracy of the rotation ratios method. MATERIAL AND METHODS: Known pelvic rotations between 165 radiographs obtained from five skeletal pelvises in an experimental material were compared with the corresponding calculated rotations to describe the accuracy of the method. The results from a clinical material of 262 pelvic radiographs from 46 patients defined the ranges of rotational differences compared. Repeated analyses, both on the experimental and the clinical material, were performed using the selected reference points to describe the robustness and the repeatability of the method. RESULTS: The reference points were easy to identify and barely influenced by pelvic rotations. The mean differences between calculated and real pelvic rotations were 0.0 degrees (SD 0.6) for vertical rotations and 0.1 degrees (SD 0.7) for transversal rotations in the experimental material. The intra- and interobserver repeatability of the method was good. CONCLUSION: The accuracy of the method was reasonably high, and the method may prove to be clinically useful.

Validity and stability of a computerized metabolic system with mixing chamber.

The aim of this study was to validate a computerized metabolic system with mixing chamber (Oxycon Pro, Erich Jaeger GmbH, Hoechberg, Germany) against the Douglas bag method (1) over a large range of ventilations and (2) for drift during shorter (25-min time trial) and longer (approximately three months) test periods. Eighteen well-trained/elite cyclists performed graded exercise tests, maximal oxygen uptake tests and time trial tests on an electromagnetic braked cycle ergometer. Respiratory variables were measured simultaneously, once or several times in every test by the Oxycon Pro and the Douglas bag method. (1) Overall, oxygen uptake was 0.8 % (0.03 l x min(-1)) lower with the Oxycon Pro than with the Douglas bag method with a coefficient of variation of 1.2 % (n = 802) (p < 0.05). (2) During the time trials, oxygen uptake measured with the Oxycon Pro gradually decreased from 0.5 % (0.02 l) lower than the Douglas bag method at 5 min to 1.0 % (0.05 l) lower at 25 min (p < 0.05). Over the period of three months of testing, oxygen uptake measured with the Oxycon Pro gradually increased from 1.1 % (0.04 l) lower than the Douglas bag method at the start to 0.5 % (0.02 l) lower at the end (p < 0.05). This study demonstrates that a computerized metabolic system with mixing chamber is an accurate system for measuring oxygen uptake. This applies to testing over a large range of ventilations and for stability both during shorter and longer test periods.

Treatment of hypertensive and hypercholesterolaemic patients in general practice. The effect of captopril, atenolol and pravastatin combined with life style intervention.

OBJECTIVE: To elucidate the effect on blood pressure and blood lipids of an angiotensin converting enzyme inhibitor (captopril), and a beta-receptor blocking agent (atenolol), given alone or in combination with a cholesterol reducing drug, the beta-hydroxy-methylglutaryl-coenzyme A reductase inhibitor pravastatin, in patients who were also encouraged to improve their lifestyle. DESIGN: A longitudinal study consisting of three phases. I: Lifestyle intervention alone. II: Continued lifestyle intervention combined with captopril or atenolol. III: Continued lifestyle intervention combined with the same drugs as in phase II and in addition pravastatin or placebo. SETTING: Fifty-four general practice surgeries in Norway. PARTICIPANTS: Hypertensive patients, 210 females and 160 males, treated or untreated with antihypertensive drugs with a sitting diastolic blood pressure between 95 and 115 mmHg and a serum total cholesterol between 6.5 mmol/l (7.0 for those age 60-67 years) and 9.0 mmol/l. RESULTS: The antihypertensive effect of captopril and atenolol was not influenced by concurrent administration of pravastatin. The effect of pravastatin was not limited by concurrent medication with captopril or atenolol. Improvement in lifestyle seemed to reduce the need for supplementary treatment with diuretics. CONCLUSION: Pravastatin can be used in combination with captopril or atenolol in the treatment of hypertensive and hypercholesterolaemic patients.

[Can we rely on self-reported smoking habits?]. / Kan vi stole på egenerklaerte røykevaner?

The reliability of self-reporting on smoking habits has been evaluated by comparing the reported smoking habits with the concentration of serum thiocyanate, which is higher in smokers than in non-smokers and increases with increasing cigarette consumption. When a smoker stops smoking, the level of serum thiocyanate decreases and falls to the level observed in non-smokers after about one month. When the questions asked about smoking were neutral, the reported smoking habits were generally reliable. However, in cases where the questions asked and the interview situation could be regarded as unpleasant, the reported smoking habits were not always correct. Some smokers underreported the number of cigarettes they smoked on a daily basis and some of them denied smoking altogether.

Do pregnant women who report a reduction in cigarette consumption consume less tobacco?

OBJECTIVE: To investigate the relationship between changes in self-reported cigarette consumption and changes in serum thiocyanate among pregnant and non-pregnant women who participated in a smoking cessation trial. DESIGN: Intervention study. SETTING: General practitioners in western Norway. SUBJECTS: 146 pregnant and 102 non-pregnant women who were daily smokers at inclusion. Self-reported cigarette consumption and serum thiocyanate were recorded at inclusion and after 12 months. RESULTS: Women who smoked in the first trimester of pregnancy reported 21% less cigarette consumption than non-pregnant women. This was in accordance with the serum thiocyanate values. Twelve months later the mean values of serum thiocyanate had increased irrespective of whether the postpartum women reported that they had reduced, increased, or not changed their cigarette consumption. However, among those who reported that they had stopped smoking, analyses of serum thiocyanate confirmed their statements, with very few exceptions. Among nonpregnant women, the serum thiocyanate changed in accordance with the reported changes in cigarette consumption in all groups. CONCLUSION: Women smoking daily in the first trimester of pregnancy had a lower exposure to tobacco than daily smoking non-pregnant women. Twelve months later (six months after delivery) analyses of serum thiocyanate indicated that postpartum women underestimated their tobacco consumption.

Is smoking intervention in general practice more successful among pregnant than non-pregnant women?

The objective of this study was to evaluate the effect of a simple smoking intervention programme, carried out by a large number of general practitioners (GPs) among pregnant and non-pregnant women. Four groups of women were defined by the dichotomies pregnant versus non-pregnant and intervention versus control. The intervention was semistructured, using a flip-over and a booklet, and it was implemented in an ordinary sequence of consultations. The study involved 187 GPs in western Norway. The subjects were 350 daily smoking pregnant women and 274 daily smoking non-pregnant women, 18-34 years of age. The point prevalence abstinence rate at 18 months was 15 and 20% for pregnant and non-pregnant women, respectively, in the intervention groups, and 7% in the control groups (Ppregnant = 0.06, Pnon-pregnant = 0.006). Twenty-five per cent of the pregnant women and 34% of the non-pregnant women reported that they had reduced their cigarette consumption, but had not stopped smoking entirely. If we include all drop-outs as smokers, the continuous abstinence rate during 15 months was 6%/0% among pregnant women (intervention/control) and 5%/1% among non-pregnant women. Stopping smoking was associated with having a non-smoking partner (P = 0.001), and being encouraged to do so by their partner (P = 0.004). The prevalence of both pregnant and non-pregnant women who stopped smoking was higher in the intervention than in the control groups. Pregnant women stopped smoking as frequently as non-pregnant individuals.(ABSTRACT TRUNCATED AT 250 WORDS)