Does total knee arthroplasty modify flexion axis of the knee?

PURPOSE: To prospectively investigate whether preoperative functional flexion axis in patients with osteoarthritis- and varus-alignment changes after total knee arthroplasty and whether a correlation exists both between preoperative functional flexion axis and native limb deformity. METHODS: A navigated total knee arthroplasty was performed in 108 patients using a specific software to acquire passive joint kinematics before and after implant positioning. The knee was cycled through three passive range of motions, from 0° to 120°. Functional flexion axis was computed using the mean helical axis algorithm. The angle between the functional flexion axis and the surgical transepicondylar axis was determined on frontal (α (F)) and axial (α (A)) plane. The pre- and postoperative hip-knee-ankle angle, related to femur mechanical axis, was determined. RESULTS: Postoperative functional flexion axis was different from preoperative only on frontal plane, while no differences were found on axial plane. No correlation was found between preoperative α (A) and native limb deformity, while a poor correlation was found in frontal plane, between α (F) and preoperative hip-knee-ankle angle. CONCLUSIONS: Total knee arthroplasty affects functional flexion axis only on frontal plane while has no effect on axial plane. Preoperative functional flexion axis is in a more varus position respect to the transepicondylar axis both in pre- and postoperative conditions. Moreover, the position of the functional axis on frontal plane in preoperative conditions is dependent on native limb alignment, while on axial plane is not dependent on the amount of preoperative varus deformity.

Specific magnetic isolation for direct detection of HPV16.

Finding a suitable DNA purification system is vital for the success of many PCR based diagnostic tests. This report demonstrates the value of magnetic beads in combination with real-time PCR for the sequence-specific isolation and detection of episomal HPV16 DNA. In order to maximize the isolation, two purification procedures were evaluated. Compared to the indirect method, in which the target was magnetically labeled after being hybridized to the capture probes, much higher efficiencies were obtained by directly capturing the target using DNA functionalized beads. These higher efficiencies were obtained by carefully tuning the capture probe density on the beads. When modifying the beads with dual-biotinylated capture probes or introducing beads modified with different capture probes, the amount of HPV16 isolated from spiked clinical swab samples even increased further. This not only resulted in the use of dual-biotinylated capture probes in higher purification efficiencies, but also the thermostability of the DNA-bead linkage was found to improve. In summary, this study shows that DNA functionalized magnetic beads are very promising diagnostic tools as they allow for a specific, simple, and fast isolation and concentration of minute quantities of DNA from complex clinical samples.

Knee functional flexion axis in osteoarthritic patients: comparison in vivo with transepicondylar axis using a navigation system.

PURPOSE: No study, up to now, has examined the effect of arthritis on pathologic subjects using functional flexion axis (FFA). The purpose of this study is to understand whether arthritis affects somehow the FFA evaluation and to assess whether the FFA could be considered a usable reference for implant positioning for osteoarthritic knees. METHODS: Using a navigation system, FFA orientation was evaluated intraoperatively (computed with the mean helical axis method) in three different ranges of motion (0°-120°; 35°-80°; 35°-120°) and in two different planes (coronal and axial), for 111 osteoarthritis patients undergoing total knee arthroplasty. The results were compared with a control group of 60 patients that underwent ACL reconstruction. The angle between the transepicondylar axis (TEA) and FFA was computed. RESULTS: Results showed in arthritic knees on frontal plane, an average difference between TEA and FFA of -2.8° ± 5.0° while on axial plane it was 0.6° ± 4.7°. No statistical difference was found between the three ranges in axial view, whereas some difference was found in frontal view (P < 0.0001). The TEA-FFA angle was not correlated with limb alignment on axial plane, while it was, even if poor, in frontal plane. In the control group, in frontal and in axial view, no statistical difference was found for the angle between TEA and FFA. CONCLUSIONS: FFA can be used as reference for implant positioning in axial plane also in pathologic knees, while for the frontal plane further investigations are required.

Waveguide-based absorption measurement system for visible wavelength applications.

We present a miniaturized waveguide-based absorption measurement system operating at a wavelength of 635 nm, based on a silicon nitride integrated photonic platform, suitable for lab-on-chip applications. We experimentally demonstrate a high correlation between the bulk dye concentration and the measured absorption loss levels in the waveguides. We explain a photonic design process for choosing the ideal waveguide to minimize the coefficient of variation on the analyte concentration. The approach is designed for camera readout, allowing multiple readouts and easy integration for lab-on chip cartridge approach.

Single-bubble and multibubble cavitation in water triggered by laser-driven focusing shock waves.

In this study a single laser pulse spatially shaped into a ring is focused into a thin water layer, creating an annular cavitation bubble and cylindrical shock waves: an outer shock that diverges away from the excitation laser ring and an inner shock that focuses towards the center. A few nanoseconds after the converging shock reaches the focus and diverges away from the center, a single bubble nucleates at the center. The inner diverging shock then reaches the surface of the annular laser-induced bubble and reflects at the boundary, initiating nucleation of a tertiary bubble cloud. In the present experiments, we have performed time-resolved imaging of shock propagation and bubble wall motion. Our experimental observations of single-bubble cavitation and collapse and appearance of ring-shaped bubble clouds are consistent with our numerical simulations that solve a one-dimensional Euler equation in cylindrical coordinates. The numerical results agree qualitatively with the experimental observations of the appearance and growth of large bubble clouds at the smallest laser excitation rings. Our technique of shock-driven bubble cavitation opens interesting perspectives for the investigation of shock-induced single-bubble or multibubble cavitation phenomena in thin liquids.

Postural visual dependence after recent stroke: assessment by optokinetic stimulation.

INTRODUCTION: This study was conducted to assess visual dependence of postural control early after stroke. DESIGN: Case control study. SETTING: A Physical Medicine and Rehabilitation Department. METHOD: Twenty-five patients impaired by severe hemiplegia due to a recent first stroke, were examined. Fourteen had a right and 11 a left hemispheric lesion. There were aged 52+/-13 years, time since stroke was 30+/-12 days. Patients' data were compared to data for 25 healthy subjects. Sitting posture was assessed on a dynamic balance, using two parameters: frontal plane displacement of the centre of pressure under optokinetic stimulation (OKS), and the total length of centre of pressure displacement for the stability reaction. On the basis of 90th percentile control data, patients' behaviour was classified as totally visuo independent (VI), totally visuo dependent (VD) or mixed. RESULTS: Body tilt under OKS was greater in patients than controls. No control subject was totally VD, 19 subjects were totally VI. Four patients were totally VD and only six were VI. The only clinical parameter linked to the effect of OKS was the sensitivity impairment. Overall patients with visuospatial neglect were the most perturbed, but two were totally visuo independent. DISCUSSION AND CONCLUSION: Assessment of postural variations in sitting under OKS is proposed for estimating visual dependence early after stroke. Individual reactions are more important than mean group reactions. Visual dependence is not solely due to neurological impairment, implying that previous physiological behaviour may be involved. Knowledge of these characteristics may affect rehabilitation programmes.

Fatigue after stroke.

OBJECTIVES: To examine the phenomenon of fatigue after stroke and to review the knowledge about frequency, consequences, associated factors, physiopathology and treatment. MATERIALS AND METHOD: Medline was systematically searched with the following keywords: stroke, fatigue, sleep disorders, exercise, and rehabilitation. All relevant articles found in the references were screened as well. RESULTS AND DISCUSSION: Fatigue is a common complaint after stroke and occurs in 39-72% of stroke survivors. Some studies show a severe functional impact of this symptom as well as a high mortality rate. Available evidence concerning associated factors is limited, but fatigue is clearly multifactorial. Some studies show that limited exercise capacity, increased gait energy cost, sleep-disordered breathing and sleep disorders can be related to physical fatigue. Other studies show a link between fatigue and depression. The existence of primary fatigue is still controversial. Treatment must follow a diagnostic approach. Treadmill training, among other treatments, improves fitness reserve and lowering of the energy cost of hemiparetic gait, which could be useful in relieving fatigue.

[Evaluation of the disabilities of hemiplegic patients]. / Evaluation des incapacités fonctionnelles chez le patient hémiplégique: mise au point.

OBJECTIVES: To identify and describe the most useful functional disability scales for assessing post-stroke hemiplegic patients and those used largely in clinical trials. METHODS: A literature review of Medline about the functional parameters for balance, gait and mobility, upper extremity functional abilities, and activities of daily living. The metrologic properties of the scales were specified as were their clinical use. RESULTS: Thirty-three scales were evaluated and classified into five categories: balance (6 scales), gait and mobility (4), upper limb function (11), global motricity scales (5) and independence in activities of daily living (7). DISCUSSION AND CONCLUSION: Many functional scales are useful for assessing post-stroke hemiplegic patients. To assess balance, the Postural Assessment Stroke Scale and Berg Balance Scale are the most interesting. The Functional Ambulation Classification and the Timed Up and Go Test are the most relevant to assess gait and mobility. The Action Research Arm Test is largely used to assess upper limb functional abilities. The Functional Independence Measure and the Barthel Index are largely used to assess independence in activities of daily living.

[Pontine infarct after fracture of the skull base]. / Infarctus protubérantiel et fracture de la base du crâne.

We report a case of pontine infarct that occurred after facial trauma with a fracture of the skull base. Reports of trauma-induced pontine infarcts have generally involved cervical trauma. This is the first report to our knowledge after facial trauma with skull base fracture. We suggest that intracranial vertebro-basilar dissection could be a possible mechanism.

[Critical analysis of a systematic review of the literature and a meta-analysis on exercise therapy and chronic low back pain]. / Critique d'une revue systématique de la littérature en vue d'une méta-analyse concernant les exercices physiques et lombalgies chroniques.

OBJECTIVES: To determine wether the type of quality assessment scale used for evaluating the role of the physical training in chronic low back pain affects the conclusions of meta-analytic studies. DESIGN AND SETTING: Analysis of 20 trials assessing exercise therapy in chronic low back pain using 16 different scales to identify high-quality trials. Correlations between the scale scores were assessed using the Spearmans rank correlation coefficient. Inter-reader reliability was assessed with the intraclass correlation coefficient (ICC) and with the Bland and Altman technique. For the quality assessment scales allowing the classification in high quality or low quality trials, the degree of agreement between the two readers was calculated using the kappa coefficient. RESULTS: The range of the Spearman rank correlation coefficients between the different quality scales was wide (from 0.94 to 0.49). The quality scales inter-reader reliability were heterogeneous, ICC ranging from 0.86 to 0.39. The Bland and Altman analysis showed that with two scales the differences were not centered and that with 3 scales there was a systematic effect (r=0.32, 0.41, and 0.50). Finally, inter-reader agreement was low most of the time, the K coefficient being less than or equal to 0.60 for 8 of the 12 quality scales tested. CONCLUSIONS: Our data suggest that the use of summary scores to identify trials of high quality is problematic. Relevant methodological aspects should be assessed more specifically based on treatment strategies than on the own disease. A large reflexion on the elaboration and validation of specific quality scales is needed.

[Efficacy at six months of the botulinum toxin A in the post-stroke lower limb's muscular overactivity]. / Efficacité à six mois de la toxine botulique A dans le traitement de lhyperactivité musculaire du membre inférieur après accident vasculaire cérébral.

OBJECTIVE: Post-stroke hemiplegic patients are often disabled by a muscular overactivity of the lower limb which can be treated by botulinum toxin A (BTX). The aim of this study was to assess the length of this efficiency as expressed by the patient. MATERIAL AND METHOD: The study was conducted among consecutive patients with post-stroke hemiplegia, disabled by a distal muscular overactivity of the lower limb. The injection of BTX (Botox Allergan) was given under electrostimulation guidance. Efficiency was assessed by the patient at 1, 3 and 6 months, by means of a three-point scale (absent, real but not enough, very good), on the basis of individual objectives previously defined after the precise description of the symptoms, their type of triggering and their functional impact. RESULTS: Fifty-seven sessions were conducted in 36 patients. At 1 month, 81% of the sessions were efficient, 39% with very good results. At 6 months, 57% of the sessions were still efficient with 25% of very good results. The best results were observed on the permanent extension of the great toe: the efficiency remained very good at 6 months for 47% of the sessions. CONCLUSION: Having been assessed by the patients on the basis of individual objectives, the good result of the treatment by BTX can persist for more than 6 months. This assessment is partly subjective but is, in clinical use, the main basis for the treatment discussion.

[Interest of the criteria of Cochin to select patients with significant relief of low back pain after corticosteroid facet joint injections: a prospective study]. / Intérêt des critères de Cochin pour poser l'indication d'infiltrations articulaires postérieures chez le lombalgique chronique: étude comparative prospective.

UNLABELLED: The seven Criteria of Cochin (CC), clinical descriptive criteria of low back pain (LBP), have been shown to be able to select patients whose LBP would respond well to facet joint anesthesia. AIM: To determine if these seven criteria set are able to select patients with significant relief of LBP after corticosteroid facet joint injections (CFJI). METHODS: Ninety-one patients with chronic LBP were included in a positive group (PG) or a negative group (NG) according to the number of the positive CC. Patients placed in the PG had five or more of the positive CC and those in the NG had less than five of the positive CC. All of them received CFJI on day 0 (D0). The severity of LBP and leg pain, disability and CFJI effect were evaluated on a self-questionnaire on D0, D2, D8 and D30. RESULTS: Two hundred and seventeen CFJI were performed (mean 2.1 per patient). Compared to the initial values we observed a significant reduction of the LBP at D2, D8 and D30 in both the groups (P < 0.05), a significant augmentation of the leg pain at D30 in the GN (P < 0.05) and a significant improvement of the Quebec back pain disability scale (QBDS) at D8 and D30 in the PG (P <0.05). Compared to the NG values, the PG had a significant higher global estimation of the efficacy of the treatment (P < 0.05) and a significant lesser intensive LBP (P <0.05) on D2, D8 and D30, a significant lesser intensive leg pain (P < 0.05) on D30, and a tendency to a more important reduction of the QBDS on D8 and D30 (P > 0.05). CONCLUSION: CC seems to be an effective test to select patients whose LBP would respond well to CFJI.

Therapeutic patient education for stroke survivors: Non-pharmacological management. A literature review.

OBJECTIVES: Focus on the different therapeutic patient education (TPE) programs for stroke survivors found in the literature. Verify their content and efficacy. METHOD: A literature review was conducted by searching for entries from 1966 to 2011 in the Medline and Cochrane Library databases. The references for the accepted articles were taken into consideration and the articles corresponding to the criteria inclusion but not present within the initial search were selected. The keywords used were "self care", "self management", "patient education" and "stroke". Given the multiplicity of symptoms that may be addressed in TPE programs, and following expert advice, the symptoms were grouped after expanding the bibliographic search using the following, additional keywords: "dysphagia"; "swallowing disorder"; "urinary incontinence"; "caregiver"; "fall prevention"; "falling"; "injury"; "shoulder pain"; "physical activity"; "exercise"; "aphasia" and "cognitive impairment". RESULTS: We found 30 article abstracts. In the end, we only accepted seven articles on general TPE programs that were well structured and detailed enough. The TPE programs found in the literature were often of questionable methodological quality. The multiplicity of symptoms led to very general TPE programs that covered all possible stroke after-effects. The purpose of these programs was to reduce stress and anxiety, to improve quality of life and to alleviate psychosocial after-effects. A change in caregiver and patient behavior was observed at times. We expanded the bibliographic search to include scientific arguments that could help implement TPE programs for more specific targets. CONCLUSION: TPE programs for stroke survivors could be improved by standardizing and assessing programs that focus on a specific problem caused by the various possible after-effects of strokes. In order to promote education for stroke survivors, specific training for health care professionals and appropriate funding are necessary.

Maxillary distraction in cleft lip palate patients: a review of six cases.

Cleft lip and palate patients can present with a maxillary retrusion with tendency to Class III malocclusion after cleft repair. Maxillary distraction osteogenesis is a technique that provides simultaneous skeletal advancement and expansion of the soft tissues. Six nonsyndromic cleft lip and palate patients, ages 12 to 16 years (mean, 13.8 years), underwent maxillary distraction; four had a unilateral and two a bilateral cleft lip and palate. After an incomplete LeFort I osteotomy; a latency period of 3 days was respected. On Postoperative Day 4, distraction was initiated through anterior traction on a Delaire facial mask using distraction forces of 900 gm. Photographs and lateral cephalometric radiographs were obtained preoperatively and 4 months after distraction. A cephalometric analysis was performed to compare the sagittal dentocraniofacial morphology before and after distraction. The aesthetic improvement obtained by maxillary distraction osteogenesis during the permanent dentition to correct maxillary retrusion in our cleft lip and palate patients was impressive. Skeletal advancement varying from 1 to 3.5 mm (mean, 1.7 mm) was found. However, significant dentoalveolar compensations occurred in three patients. This was due to the dental anchorage of the distraction device and can be avoided only by the use of skeletal fixation.

Anatomic motor point localization for partial quadriceps block in spasticity.

OBJECTIVE: To identify the location of the vastus intermedius nerve and its motor point (point M) and to precisely identify its coordinates in relation to anatomic surface landmarks. DESIGN: Descriptive study. SETTING: Anatomy institute of a university school of medicine. PARTICIPANTS: Twenty-nine adult cadaver limbs immobilized in anatomic position. INTERVENTION: Anatomic dissection to identify point M. Anatomic surface landmarks were point F, the issuing point of femoral nerve under the inguinal ligament; point R, the middle of superior edge of the patella; segment FR, which corresponds to thigh length; point M', point M orthogonal projection on segment FR. MEAN OUTCOME MEASURE: Absolute vertical coordinate, distance FM, relative vertical coordinate compared to the thigh length, FM'/FR ratio; absolute horizontal coordinate, distance MM'. RESULTS: The absolute vertical coordinate was 11.7+/-2 cm. The relative vertical coordinate was at .29+/-.04 of thigh length. The horizontal coordinate was at 2+/-.5 cm lateral to the FR line. CONCLUSION: Point M can be defined with relative precision by two coordinates. Application and clinical interest of nerve blocking using these coordinates in quadriceps spasticity should be studied.