Primary cup stability in THA with augmentation of acetabular defect. A comparison of healthy and osteoporotic bone.

BACKGROUND CONTEXT: Reconstruction of acetabular defect has been advocated as standard procedure in total hip arthroplasty. The presence of bony defects at the acetabulum is viewed as a cause of instability and acetabular wall augmentation is often used without proper consideration of surrounding bone density. The initial cup-bone stability is, however, a challenge and a number of studies supported by clinical follow-ups of patients suggested that if the structural graft needs supporting more than 50% of the acetabular component, a reconstruction cage device spanning ilium to ischium should be preferred to protect the graft and provide structural stability. This study aims to (1) investigate the relationship between cup motion and bone density and (2) quantify the re-distribution of stress at the defect site after augmentation. HYPHOTESIS: Paprosky type I or II, acetabular defects, when reconstructed with bone screws supported by bioabsorbable calcified triglyceride bone cement are significantly less effective for osteoporotic bone than healthy bone. MATERIALS AND METHODS: Acetabular wall defects were reconstructed on six cadaveric subjects with bioabsorbable calcified triglyceride bone cement using a re-bar technique. Data of the specimen with higher bone density was used to validate a Finite Element Model. Values of bone apparent density ranging from healthy to osteoporotic were simulated to evaluate (1) the cup motion, through both displacement and rotation, (2) and the von Mises stress distribution. RESULTS: Defect reconstruction with bone screws and bioabsorbable calcified triglyceride bone cement results in a re-distribution of stress at the defect site. For a reduction of 65% in bone density, the cup displacement was similar to a healthy bone for loads not exceeding 300 N, as load progressed up to 1500 N, the reconstructed defect showed increase of 99 µm (128%) in displacement and of 0.08° in rotation angle. CONCLUSIONS: Based on the results, we suggest that an alternative solution to wall defect augmentation with bone screws supported by bioabsorbable calcified triglyceride bone cement, be used for osteoporotic bone. LEVEL OF EVIDENCE: Level IV, experimental and cadaveric study.

Housekeeping health care workers have the highest risk for tuberculin skin test conversion.

BACKGROUND: Not all health care workers (HCWs) are at the same risk for tuberculin skin test (TST) conversion, indicating latent tuberculosis (TB) infection. OBJECTIVE: To identify risk factors for TST conversion among HCWs. METHODS: A retrospective cohort study conducted at a tertiary university medical centre included every HCW who had had a negative two-step TST at work entry and at least one consecutive TST in the period 2005-2009 (mean follow-up period 55 months). Binomic logistic regression analysis was used to identify risk factors for TST conversion. Potential risk factors such as age, health care profession, patient exposure profile, workplace division and history of bacille Calmette-Guérin vaccination were entered in the model. RESULTS: A total of 450 subjects met the inclusion criteria, of whom 93 had TST conversion. The highest annual rates of TST conversion occurred in workers who worked as housekeeping staff (6.9%). Older age, a work environment with high patient turnover and employment in maintenance departments were significant risk factors (adjusted odds ratios 2.05, 5.2 and 8.4 respectively). CONCLUSION: Housekeeping staff, older age workers and health care professionals working in an environment of high patient turnover are at increased risk for latent TB infection.

Gender differences in the long-term outcomes after valve replacement surgery.

OBJECTIVE: To compare the long-term outcomes in women and men after valve replacement surgery. DESIGN: Observational study. SETTING: Postoperative aortic valve replacement (AVR) or mitral valve replacement (MVR). PATIENTS: 3118 patients (1261 women, 1857 men) who underwent AVR or MVR between 1976 and 2006 (2255 AVR, 863 MVR), with mean follow-up of 5.6 (4.5) years. MAIN OUTCOME MEASURES: The independent effect of gender on the risk of long-term complications (reoperation, stroke and death) after valve replacement surgery using multivariate actuarial methods. RESULTS: After implantation of an aortic valve bioprosthesis, women had a significantly lower rate of reoperation compared to men (comorbidity-adjusted hazard ratio (HR) 0.4; 95% confidence intervals (CI) 0.2 to 0.9). In contrast, if an aortic mechanical prosthesis had been implanted, women were more at risk for late stroke compared to men (HR 1.7; CI 1.1 to 2.7). After adjustment for age and co-morbidities, women had significantly better long-term survival compared to men after bioprosthetic AVR (HR 0.5; CI 0.3 to 0.6), but there was no survival difference between genders after mechanical AVR. Trends existed towards better survival for women after bioprosthetic MVR (HR 0.6; CI 0.4 to 1.0) and mechanical MVR (HR 0.8; CI 0.5 to 1.1). CONCLUSION: The long-term outcomes after valve replacement surgery differ between women and men. Although women have more late strokes after valve replacement, they undergo fewer reoperations and have better overall long-term survival compared to men.

Midterm survival of a contemporary modular total knee replacement: a multicentre study of 1970 knees.

This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1). The PFC Sigma knee system appears to provide excellent results in the medium term.

Charge-state distribution and Doppler effect in an expanding photoionized plasma.

The charge state distributions of Fe, Na, and F are determined in a photoionized laboratory plasma using high resolution x-ray spectroscopy. Independent measurements of the density and radiation flux indicate unprecedented values for the ionization parameter xi=20-25 erg cm s(-1) under near steady-state conditions. Line opacities are well fitted by a curve-of-growth analysis which includes the effects of velocity gradients in a one-dimensional expanding plasma. First comparisons of the measured charge state distributions with x-ray photoionization models show reasonable agreement.

Annualized incidence and spectrum of illness from an outbreak investigation of Bell's palsy.

BACKGROUND: There are limited clinical and epidemiological data on patients diagnosed with Bell's palsy. While investigating an apparent clustering of Bell's palsy, we sought to characterize the spectrum of illness in patients with this diagnosis. METHODS: A telephone survey of persons with idiopathic facial (Bell's) palsy in the Greater Toronto Area (GTA, population = 4.99 million) and Nova Scotia (population = 0.93 million) from August 1 to November 15, 1997 collected information on subject demographics, neurological symptoms, constitutional symptoms, medical investigation and management. Information regarding potential risks for exposure to infectious agents, past medical history, and family history of Bell's palsy was also collected. Subjects with other secondary causes of facial palsy were excluded. RESULTS: In the GTA and Nova Scotia, 222 and 36 patients were diagnosed with idiopathic facial (Bell's) palsy, respectively. The crude annualized incidence of Bell's palsy was 15.2 and 13.1 per 100,000 population in the GTA and Nova Scotia, respectively. There was no temporal or geographical clustering, and symptomatology did not differ significantly between the two samples. The mean age was 45 years, with 55% of subjects being female. The most common symptoms accompanying Bell's palsy were increased tearing (63%), pain in or around the ear (63%), and taste abnormalities (52%). A significant number of patients reported neurological symptoms not attributable to the facial nerve. CONCLUSION: No clustering of cases of Bell's palsy was observed to support an infectious etiology for the condition. Misdiagnosis of the etiology of facial weakness is common. Patients diagnosed with Bell's palsy have a variety of neurological symptoms, many of which cannot be attributed to a facial nerve disorder.

Prevalence of dislocation after total hip arthroplasty through a posterolateral approach with partial capsulotomy and capsulorrhaphy.

The senior author altered his surgical technique during total hip arthroplasty from capsulectomy and capsulotomy with closure of the external rotator muscles to capsulotomy and capsulorrhaphy. One thousand patients (500 treated with each procedure) were studied retrospectively in order to determine the prevalences of dislocation after surgery with the two different techniques. The prevalence of dislocation was 2.8% after the capsulectomy and capsulotomy, whereas it was 0.6% after the new technique; this was a significant decrease in the rate of dislocation (p < 0.005, [symbol: see text] = 0.10).

Temporary articulating methylmethacrylate antibiotic spacer (TAMMAS). A new method of intraoperative manufacturing of a custom articulating spacer.

A temporary articulating antibiotic-impregnated cement spacer for use during the first stage of a two-stage revision of a total knee replacement that had failed because of infection was developed by one of us (W.M.G.). It is simply a knee prosthesis made of methylmethacrylate and antibiotics that is manufactured intraoperatively with use of instruments, medications, and supplies that are already available at most hospitals. This construct allows for motion of the knee during treatment of the infection, thereby reducing the risk of loss of motion after subsequent revision. The technique has been successfully utilized in five patients since 1999 and has now become our standard treatment method.

Observations of the vacuum ultraviolet and x-ray brightness profiles of Fe, Ni, and Ge in magnetically confined fusion plasmas.

The spatial brightness profiles of emission lines for the K-like through He-like ionization states of Fe, Ge, and Ni have been measured during a set of experiments in which Fe and Ge were introduced into FTU tokamak plasmas by using the laser blowoff technique. Nickel was an intrinsic impurity observed during these experiments that was sputtered from the inconel limiter. The brightness profiles were measured by spatially scanable, photometrically calibrated vaccum ultraviolet and x-ray spectrometers that covered the 1 to 1700 A region. Simulations of these profiles and the time evolution of the laser blowoffs were performed with the MIST transport code using several sets of atomic physics compilations [ADPAK (originally in MIST), Arnaud and Raymond (AR92), Arnaud and Rothenflug (AR85), Mazzotta et al., and Mattioli (an extension to Mazzotta)]. The goal was to determine which set of available rates could best simulate the measured spatial brightness profiles and the charge state balance in the plasma. The Mazzotta et al. (for Fe and Ni), the Mattioli (for Ge), and the AR92 (for Fe only) rates adequately simulated the He-, Li-, Be-, Na-, Mg-like ionization states. The F- to B-like charge states could not be simulated by these compilations unless the relevant dielectronic rates were multiplied by a factor of 2. The ADPAK rates could not adequately predict any of the charge states of Fe, Ge, or Ni.

Safety of a clinical surveillance protocol with 3- and 6-week warfarin prophylaxis after total joint arthroplasty.

The charts of 1869 patients were reviewed for the occurrence of deep venous thrombosis (DVT) and pulmonary embolism after total hip or knee arthroplasty. Prophylaxis consisted of 3 (group 1; n=1235) or 6 (group 2; n=634) weeks low-dose warfarin, pneumatic compression boots worn by patients in the hospital, mobilization on the first postoperative day, and a clinical surveillance protocol. Venous ultrasound or ventilation/perfusion lung scintigraphy (V/Q) was performed only if patients became symptomatic. patients. Twenty-three (1.8%) patients were positive for DVT. Ventilation/perfusion lung scintigraphy was performed on 25 patients, and 5 (0.4%) patients were positive for pulmonary embolism. In group 2, 117 patients were evaluated for DVT, and 19 (3%) patients had positive results determined by ultrasound. Twenty-five patients were evaluated with V/Q and only 1 (0.16%) patient was positive for pulmonary embolism. No patient developed a fatal pulmonary embolism or postphlebitic syndrome. This prophylaxis protocol is an efficient and cost-effective method for the prevention of significant events after surgery.

The spectrum of electrophysiological abnormalities in Bell's palsy.

BACKGROUND: As part of an investigation of a suspected "outbreak" of Bell's palsy in the Greater Toronto Area, a population-based sample of patients with Bell's palsy was investigated electrophysiologically to help understand the spectrum of abnormalities that can be seen in this setting. METHODS: Two hundred and twenty-four patients were surveyed, of whom 91 underwent formal neurological assessment. Of the latter, 44 were studied electrophysiologically using standard techniques. Thirty-two of the 44 patients fulfilled clinical criteria for Bell's palsy. RESULTS: A wide range of electrophysiological changes was observed. Blink responses were the most useful test showing diagnostic sensitivity of 81% and specificity of 94% compared to the contralateral control side. Needle electromyography was additionally helpful in only one patient of six with normal conduction studies. CONCLUSIONS: There is a wide spectrum of electrophysiological abnormalities in Bell's palsy. Blink reflex latencies may be under-utilized in the assessment of the facial nerve in Bell's palsy. Facial EMG is not generally useful in routine assessment.

Sequential bilateral total knee arthroplasty.

As the senior citizen population has grown, the incidence of osteoarthritis and joint replacement has increased. Bilateral total knee arthroplasty (BTKA) can be performed sequentially during one anesthetic. Studies have shown the complication rates differ only slightly for total knee arthroplasty procedures performed sequentially during one anesthetic or separately requiring two hospitalizations. With the use of staggered tourniquet deflation times, efficient OR time and motion techniques, and careful postoperative management, patients can achieve successful outcomes after BTKA during one anesthetic.

The transference in psychotherapy: the old vs. the new, analytic vs. dynamic.

This article takes a look at the concept of transference from several contemporary perspectives. It compares the traditional (or classical) view of transference with a more contemporary view based on the joint creation of the transference. It then discusses the relevance of transference to the dynamically based psychotherapies. From this perspective analytically oriented psychotherapy is contrasted to dynamically oriented psychotherapy.

Dynamically oriented psychotherapy with borderline patients.

This article outlines a basic framework and strategy for a dynamically oriented psychotherapy with borderline patients. Focus includes arrangements and guidelines for psychotherapy, neutrality, the stability of the therapeutic environment, the therapeutic alliance, transference, the countertransference, activity of the therapist, types of interventions, style of interventions, interventions regarding core difficulties, the conceptual framework of anxiety and defense, trends in the psychotherapy, and termination. A differentiation between analytically oriented psychotherapy and dynamically oriented psychotherapy is provided. For one group of borderline patients, a modified analytically oriented approach is utilized throughout the entire treatment. For a second group, there is a switch from analytically oriented psychotherapy to a dynamically oriented psychotherapy, after the therapeutic alliance has become reasonably stable. Two clinical vignettes are provided.

Nonthoracotomy implantation of cardioverter defibrillators: preliminary experience with a defibrillation lead placed at the right ventricular outflow tract.

UNLABELLED: Although morbidity and mortality associated with defibrillator implantation using a nonthoracotomy approach have decreased as compared with a thoracotomy approach, defibrillation thresholds have been higher and fewer patients satisfied implant criteria. It may be possible to improve on the success of nonthoracotomy defibrillator implantation by the placement of a right ventricular (RV) outflow defibrillation lead. Implantable cardioverter defibrillator implantation data of 30 consecutive patients with clinical VT or VF were reviewed. Three defibrillation leads were routinely used. When either pacing threshold at the RV apex was inadequate (n = 2) or 18-J shocks were not successful in terminating VF in 3 of 4 trials (n = 8), the RV apex lead was positioned to the RV outflow tract attaching to the septum. Defibrillation testing was first performed with the RV apex lead in combination with CS, SVC, and/or subcutaneous leads. Twenty patients satisfied implant criteria with a defibrillation threshold of 13.5 +/- 3.6 J. In 7 of the 10 patients, whose RV lead was repositioned to the RV outflow tract, this lead in combination with SVC, CS, or subcutaneous leads produced successful defibrillation at < or = 18 J or in 3 of 4 trials. This approach improved the overall success of nonthoracotomy implantation of defibrillators from 69% to 90%. After a follow-up of 27 +/- 6 months, there was no dislodgment of the RV outflow tract defibrillation leads. CONCLUSIONS: This article reports the preliminary observation that placement of defibrillation leads to the RV outflow tract in humans was possible and without dislodgment. RV outflow tract offers an alternative for placement of defibrillation leads, which may improve on the success of nonthoracotomy defibrillator implantation.

The purposes, formation, and legal implications of PHOs.

In response to rapid changes in the health care delivery system, hospitals and physicians are exploring collaborative efforts. One of these efforts is the physician hospital organization (PHO). This article explores the purposes for forming PHOs, their actual formation, and related legal issues.