First-time revision using impacted morsellised allograft bone with a cemented Exeter stem: radiostereometric analysis of stem migration over nine years.

Previously, radiostereometric analysis following hip revision performed using impacted morsellised allograft bone and a cemented Exeter stem has shown continuous subsidence of the stem for up to five years. It is not known whether the subsidence continues thereafter. In our study, 17 of 25 consecutive osteo-arthritic patients with aseptically loose stems who underwent first-time revision using impacted morsellised allograft bone and a cemented Exeter stem were followed by yearly radiostereometric examinations for nine years. The mean subsidence at six weeks was 1.1 mm (0.1 to 2.3), from six weeks to one year 1.3 mm (0 to 2.6), from one to five years 0.7 mm (0 to 2.0), and from five to nine years 0.7 mm (0.1 to 3.1). That from six weeks to nine years was 2.7 mm (0 to 6.4) (95% confidence interval 2.0 to 3.5). The Charnley pain score significantly improved after revision, and was maintained at nine years, but walking ability deteriorated slightly as follow-up extended. Of the eight patients who were not followed for nine years, two had early subsidence exceeding 11 mm. Our findings show that in osteo-arthritic patients who undergo revision for aseptic loosening of the stem using impacted morsellised allograft bone and a cemented Exeter stem, migration of the stem continues over nine years at a slower rate after the first year, but without clinical deterioration or radiological loosening.

Femoral impaction bone grafting with the Exeter stem - the Swedish experience: survivorship analysis of 1305 revisions performed between 1989 and 2002.

We identified 1305 femoral impaction bone grafting revisions using the Exeter stem performed between 1989 and 2002 in 30 hospitals throughout Sweden. There were 1188 patients with a mean age of 71 years (29 to 94) followed up for between five and 18 years. The participating departments reported 70 further revisions in total, of which 57 could also be identified on the Swedish National Arthroplasty Registry. Kaplan-Meier survivorship for all causes of failure was 94.0% (95% confidence interval (CI) 92 to 96) for women and 94.7% (95% CI, 92 to 96) for men at 15 years. Survivorship at 15 years for aseptic loosening was 99.1% (95% CI 98.4 to 99.5), for infection 98.6% (95% CI 97.6 to 99.2), for subsidence 99.0% (95% CI 98.2 to 99.4) and for fracture 98.7% (95% CI 97.9 to 99.2) Statistically significant predictors of failure were the year in which revision was conducted (p < 0.001). The number of previous revisions was slightly above the level of significance (p = 0.056). Age, gender, the length of the stem and previous septic loosening were not predictors of failure (p = 0.213, p = 0.399, p = 0.337, p = 0.687, respectively). The difference in survivorship between high- and low-volume departments was only 3% at ten years. We conclude that impaction bone grafting with the Exeter stem has an excellent long-term survivorship following revision arthroplasty. The technique of impaction grafting appears to be reliable, can be learned rapidly and produces a predictably low incidence of aseptic loosening.

The SF-6D health utility index in carpal tunnel syndrome.

Cost effectiveness is an important factor to consider when choosing between various hand surgical interventions. Health utility measures can be used to determine cost effectiveness. The SF-6D is a health utility index derived from 11 items of the SF-36 quality of life questionnaire; values range from 0.296 to 1.0 ("perfect" health). We evaluated the validity of the SF-6D in patients with carpal tunnel syndrome (CTS) who completed the SF-36 and the CTS symptom severity and functional status questionnaire before and 3 months after carpal tunnel release. Complete responses to the SF-6D items were available for 100 patients at baseline and 95 patients at baseline and follow-up. The mean SF-6D health utility index was 0.69 (SD 0.13) before surgery and 0.77 (SD 0.13) after surgery (moderate effect size). The SF-6D could discriminate between patient groups differing in self-rated global health and in whether, or not, they had a minimal clinically important improvement in CTS symptom severity after surgery. The SF-6D appears to be a valid measure of health utilities in patients with CTS and can be used in cost effectiveness studies.

Pubertal bone growth in the femoral neck is predominantly characterized by increased bone size and not by increased bone density--a 4-year longitudinal study.

Fragility fractures are correlated to reduced bone size and/or reduced volumetric bone density (vBMD). These region-specific deficits may originate from reduced mineral accrual and/or reduced skeletal growth during the first 2 decades of life. Before pathological development can be defined, normal skeletal growth must be described. To evaluate growth of bone size, accrual of bone mineral content (BMC), areal bone mineral density (aBMD) and vBMD in a population-based cohort, 44 boys and 42 girls were followed by annual measurements from the age of 12 to 16 (attendance rates 90-100%). Segmental bone length, bone width, BMC, aBMD and vBMD were measured by dual-energy X-ray absorptiometry (DXA). Data were compared with predicted adult peak, as determined in 36 men aged 27.7+/-4.6 years and 44 women aged 26.8+/-4.9 years. Growth in width of the femoral neck precedes accrual of BMC in the femoral neck in both genders up to age 15. The girls were at all ages closer to their predicted adult peak in both bone width and BMC compared with the boys except in the femoral neck. As femoral neck vBMD had reached its predicted adult peak already at 12 years in both genders, the increase in femoral neck BMC and femoral neck aBMD from age 12 to 16 was most likely to be explained by the increase in bone size. In boys the peak velocity growth was recorded at ~14 years for BMC, height, width and lean mass. Growth from the age of 12 to 16 seems to build a bigger but not a denser skeleton in the femoral neck.

Physical activity increases bone size in prepubertal boys and bone mass in prepubertal girls: a combined cross-sectional and 3-year longitudinal study.

This study evaluates the effect on the skeleton of physical activity from age 9 to 16. In 42 girls and 44 boys, bone mass and bone size were evaluated longitudinally by dual-energy X-ray absorptiometry (DXA) from ages 13 to 16. Physical activity from ages 9 to 13 was cross-sectionally evaluated at baseline (age 13). Girls with high physical activity from ages 9 to 13 at baseline had higher femoral neck bone mineral content (FN BMC; g) (P = 0.07), higher FN areal bone mineral density (FN aBMD; g/cm2), and higher FN volumetric BMD (FN vBMD; g/cm3) (both P < 0.05) compared with girls of low activity. FN width (cm) and head aBMD (an unloaded region) showed no differences when comparing the two groups. Three years of further high and low activity (from ages 13 to 16) did not yield any increased differences between the two groups. Boys with high physical activity from ages 9 to 13, had at baseline higher FN BMC, FN aBMD, and FN width (all P < 0.05) compared with boys with low activity. FN vBMD and head aBMD showed no differences when comparing the two groups. Three years of further high and low activity did not yield any increased differences between the two groups. We conclude that exercise may yield skeletal benefits before age 13, and that 3 years of continued high or low level activity up to age 16 did not yield any increased differences in bone size or bone mass in either girls or boys.

The evaluation of brain CBF and mitochondrial function by a fiber optic tissue spectroscope in neurosurgical patients.

The brain of neurosurgical patients are exposed to various manipulations in the ICU or during surgery. Under such conditions brain O2 balance may become negative and as a result brain vitality and function will deteriorate. In order to evaluate brain vitality in real time it is important to measure more than one parameter. The multiparametric monitoring system used in our previous study to monitor comatose patients (Mayevsky et al., Brain Res. 740: 268-274, 1996) was changed into a "simplified" tissue spectroscope for real time monitoring of brain O2 balance. Mitochondrial function was evaluated by monitoring the NADH redox state by surface fluorometry. Microcirculatory blood flow was assessed by laser Doppler flowmetry. The combined optical probe was located on the surface of the brain during various neurosurgical procedures and the responses were recorded and presented in real time to the surgeon. A total of 32 patients were monitored during various procedures. The results could be summarized as follows: 1. Hypercapnia led to 3 different types of responses. In two patients the 'stealing' like event was recorded. In the other 7 patients the responses to high CO2 was not detectable. In the last group of 6 patients a clear CBF elevation was recorded with variable response of mitochondrial NADH. 2. Our monitoring device was able to evaluate the efficacy of the STA-MCA anastomosis during aneurysm surgery. 3. A significant correlation was recorded between CBF and NADH redox state during changes in blood pressure, papaverine injection, spontaneous drop in blood supply to the brain or during releasing of high ICP levels. We conclude that in order to evaluate the metabolic state of the brain during neurosurgical procedures it is necessary to monitor both CBF and mitochondrial NADH by using the tissue spectroscope.

Titration in the treatment of the more troubled patient.

This article defines and discusses a modification of technique recommended by the authors in the psychoanalytic treatment of more troubled patients--a modification they call titration. Titration is defined as a conscious decision by the analyst to increase or decrease assistance (or gratification) gradually, in order to facilitate the analytic process. The authors emphasize the complexity of decisions in treatment by focusing on the decision-making processes that titration requires. Guidelines and a case vignette are presented. The authors conclude by considering some of the politics involved in the introduction of technique modifications, the salience of the titration concept, and directions for further exploration.

Results of hip revision using the Exeter stem, impacted allograft bone, and cement.

The Exeter stem and impacted, morselized allograft bone and cement were used in the revisions of 18 consecutive femoral components (17 patients). The primary arthroplasty had been done because of osteoarthritis. All of the femoral components were revised for the first time because of aseptic loosening. The migration pattern of the Exeter stem after revision was studied using roentgen stereophotogrammetric analysis. At 2 years after surgery, all 18 femoral stems had migrated in the distal direction (average, 2.5 mm). In addition, seven of the stems had migrated in the medial direction (average, 1.3 mm), and two stems had migrated in the lateral direction (0.5 mm and 1 mm, respectively). Sixteen of the femoral stems also had migrated in the posterior direction (average, 2.9 mm), but none migrated in the anterior direction. The migration rate decreased gradually with time during the followup. Six femoral stems continued to migrate between 1.5 and 2 years after surgery. In patients with major femoral bone deficiency at the time of hip revision, the use of impacted morselized allograft bone and cement yielded an initial fixation similar to that obtained in conventionally cemented revisions. Pain had improved in all patients at the 2-year followup.

Evaluation of accuracy and precision of bone markers for the measurement of migration of hip prostheses. A comparison of conventional measurements.

Our aim was to determine whether tantalum m arkers improved the accuracy and/or precision of methods for the measurement of migration in total hip replacement based on conventional measurements without mathematical correction of the data, and with Ein Bild Roentgen Analyse - Femoral Component Analysis (EBRA-FCA) which allows a computerised correction. Three observers independently analysed 13 series of roentgen-stereophotogrammetric-analysis (RSA)-compatible radiographs (88). Data were obtained from conventional measurements, EBRA-FCA and the RSA method and all the results were compared with the RSA data. Radiological evaluation was also used to quantify in how many radiographs the intraosseous position of the bone markers had been simulated. The results showed that tantalum markers improve reliability whereas they do not affect accuracy for conventional measurements and for EBRA-FCA. Because of the danger of third-body wear their implantation should be avoided unless they are an integral part of the method.

Peripubertal moderate exercise increases bone mass in boys but not in girls: a population-based intervention study.

On the basis of cross-sectional studies in elite athletes and longitudinal studies, physical activity in growing children has been suggested to enhance bone mineral acquisition and prevent osteoporosis later in life. The level of exercise in most of these studies is not applicable in a population on a day-to-day basis. The aim of this study was to determine whether moderate increased exercise within the school curriculum from age 12 to 16 years would have anabolic bone effects. In a population-based setting of 40 boys and 40 girls the school curriculum was enhanced to physical education 4 times per week for 3-4 years. Controls were 82 boys and 66 girls who had had physical education twice a week over a corresponding period. Both cases and controls were measured at age 16 years. Bone mineral content (BMC), areal bone mineral density (aBMD), bone size (femoral neck width) and volumetric BMD (vBMD) were measured in total body, spine and femoral neck (FN) by dual-energy X-ray absorptiometry. Data are presented as mean +/- SD. BMC (8 +/- 15%, p = 0.04), aBMD (9 +/- 13%, p = 0.002) and vBMD (9 +/- 15%, p = 0.001) were all higher in FN in the male intervention group compared with controls. FN bone size was no higher in the intervention group than in the controls. In girls, no differences were found when comparing the intervention group with controls. The results remained after adjusting for confounding factors such as weight, height, milk intake and activity after school. In summary, we report that increased bone mass can be achieved in a population-based cohort of boys (but not in girls) by moderate increased physical activity within the school curriculum from age 12 to 16 years. We speculate that the same results can be seen in girls if intervention starts at an earlier age. We conclude that increasing the physical education content of the Swedish school curriculum may improve bone mass in at least peripubertal boys.

Radiostereometric analysis in hip revision surgery--optimal time for index examination: 6 patients revised with impacted allografts and cement followed weekly for 6 weeks.

We revised the hip (6 stems and 5 sockets) with impacted morselized allografts and cement in 6 patients. We followed prosthetic migration by roentgen radiostereometric analysis (RSA) every 7th day for 6 weeks after the first (index) examination performed on the first postoperative day before mobilization. Most of the migration occurred during the first 2 weeks. In most cases more than half of the distal stem migration was seen between the 1st and 14th days. In all cases, the stem and socket migrations slowed down gradually and several prosthetic components had become stable after 5 weeks. We conclude that it is essential to perform the index RSA examination on the 1st or 2nd day after surgery and to state when and how weight bearing should be permitted. Otherwise it will be difficult to compare prosthetic migration in various studies and define normative values for migration predicting survival.

[Prevalence for clinically proved carpal tunnel syndrome is 4 percent]. / Prevalensen för kliniskt säkerställt karpaltunnelsyndrom 4 procent.

This article summarizes the results of a large-scale population-based study conducted to determine the prevalence of carpal tunnel syndrome in the Swedish general population. The study utilized a health questionnaires as well as clinical and electrophysiological examinations. Population prevalence rates of carpal tunnel syndrome, based on clinical diagnosis and electrophysiological criteria, were calculated. Obesity and specific work-related hand activities were shown to be risk factors for carpal tunnel syndrome.

Median nerve latency measurement agreement between portable and conventional methods.

A portable nerve conduction testing device was compared with a conventional method of measuring median nerve distal latencies. In a population-based study, a health questionnaire was mailed to a random sample of 3000 participants (aged 25 to 74 years). Two hundred and sixty-two responders with numbness and/or tingling in the median nerve distribution, and 125 asymptomatic responders underwent clinical examination as well as portable and conventional median nerve distal latency measurements. Motor latency measured with the portable device was on average 0.1 millisecond (ms) lower than motor latency measured with the conventional method (95% limits of agreement, -0.8-0.5 ms). Sensory latency (wrist-to-index finger) measured with the portable device was on average 0.3 ms lower than sensory latency (long finger-to-wrist) measured with the conventional method (95% limits of agreement, -0.7-0.1 ms). Strong correlations were found between the latencies measured by the portable and conventional methods (Pearson correlation coefficient, 0.90-0.93). The agreement between the portable and conventional methods in measuring median nerve distal latencies appears to be acceptable. The cut-off value for abnormal sensory latency needs to be lower for the portable than the conventional method if the present measurement techniques are used.

The Harrington reconstruction for advanced periacetabular metastatic destruction: good outcome in 32 patients.

We report the outcome in 32 patients operated on for advanced periacetabular metastatic destruction, where all but 2 had Harrington class III destruction. The patients were operated on using the Harrington reconstruction technique, where threaded pins and cement and a total hip replacement are used to reconstruct the acetabulum and ilium. The median survival was 11 (0-106+) months. 13 patients lived for a year or more. At follow-up after 1 year, 10 of the 13 were free of pain at rest and weight-bearing, 6 were walking with and 7 without support, and 11 lived outside a health care facility. 2 patients died within 2 weeks of surgery, both of excessive peroperative bleeding. 2 patients had dislocations, 1 developed a deep infection, and 2 patients deep vein thrombosis. There were no complications caused by erroneous pin placement or intraoperative thromboembolic incidents. There were no mechanical failures, or radiographic signs of loosening, of the pelvic components. The Harrington reconstruction technique is an effective and long-lasting method to relieve pain and restore function in patients with advanced periacetabular metastatic destruction.

Migration of the acetabular component after revision with impacted morselized allografts: a radiostereometric 2-year follow-up analysis of 21 cases.

In a consecutive series of hip revisions due to mechanical loosening, using impacted morselized allografts and cement, we followed 21 acetabular components by radiostereometric analysis (RSA) during 2 years. All but 1 acetabular component migrated in the proximal direction (median 2.1 (0.5-6.4) mm). 6 components migrated in the medial direction (median 0.8 (0.4-1.2) mm) and 6 in the lateral (median 0.8 (0.4-2.0) mm). 14 components migrated in the posterior direction (median 0.8 (0.3-2.3) mm) and 1 in the anterior 0.6 mm. The migration rate gradually decreased in all directions, but 7 acetabular components still migrated in at least 1 direction (median 0.3-0.6 mm) between 1.5 and 2 years postoperatively.

Prevalence of carpal tunnel syndrome in a general population.

CONTEXT: Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in the hands and is an important cause of work disability. Although high prevalence rates of CTS in certain occupations have been reported, little is known about its prevalence in the general population. OBJECTIVE: To estimate the prevalence of CTS in a general population. DESIGN: General health mail survey sent in February 1997, inquiring about symptoms of pain, numbness, and tingling in any part of the body, followed 2 months later by clinical examination and nerve conduction testing of responders reporting symptoms in the median nerve distribution in the hands, as well as of a sample of those not reporting these symptoms (controls). SETTING: A region in southern Sweden with a population of 170000. PARTICIPANTS: A sex- and age-stratified sample of 3000 subjects (age range, 25-74 years) was randomly selected from the general population register and sent the survey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic responders, 81% underwent clinical examination. MAIN OUTCOME MEASURES: Population prevalence rates, calculated as the number of symptomatic responders diagnosed on examination as having clinically certain CTS and/or electrophysiological median neuropathy divided by the total number of responders. RESULTS: Of the 2466 responders, 354 reported pain, numbness, and/or tingling in the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence interval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%). Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symptomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic subjects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95% CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological median neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%). CONCLUSION: Symptoms of pain, numbness, and tingling in the hands are common in the general population. Based on our data, 1 in 5 symptomatic subjects would be expected to have CTS based on clinical examination and electrophysiologic testing.

Accuracy of EBRA-FCA in the measurement of migration of femoral components of total hip replacement. Einzel-Bild-Röntgen-Analyse-femoral component analysis.

Several methods of measuring the migration of the femoral component after total hip replacement have been described, but they use different reference lines, and have differing accuracies, some unproven. Statistical comparison of different studies is rarely possible. We report a study of the EBRA-FCA method (femoral component analysis using Einzel-Bild-Röntgen-Analyse) to determine its accuracy using three independent assessments, including a direct comparison with the results of roentgen stereophotogrammetric analysis (RSA). The accuracy of EBRA-FCA was better than +/- 1.5 mm (95% percentile) with a Cronbach's coefficient alpha for interobserver reliability of 0.84; a very good result. The method had a specificity of 100% and a sensitivity of 78% compared with RSA for the detection of migration of over 1 mm. This is accurate enough to assess the stability of a prosthesis within a relatively limited period. The best reference line for downward migration is between the greater trochanter and the shoulder of the stem, as confirmed by two experimental analyses and a computer-assisted design.

Factors affecting the pharmacokinetic characteristics of rapacuronium.

BACKGROUND: Rapacuronium is a new nondepolarizing muscle relaxant with rapid onset and offset. As part of a study to determine its neuromuscular effects, the authors sampled plasma sparsely to determine the influence of age, gender, and other covariates on its pharmacokinetic characteristics. METHODS: Of 181 patients receiving a single bolus dose of 0.5-2.5 mg/kg rapacuronium, 43 (aged 24-83 yr) had plasma sampled 3 or 4 times to determine plasma concentrations of rapacuronium and its metabolite, ORG9488. Pharmacokinetic analysis was performed using a population approach (mixed-effects modeling) to determine the influence of demographic characteristics and preoperative laboratory values on the pharmacokinetic parameters. RESULTS: Rapacuronium's weight-normalized plasma clearance was 7.03 x (1 - 0.0507 x (HgB - 13)) ml x kg(-1) x min(-1), where HgB is the patient's preoperative value for hemoglobin (g/100 ml); however, rapacuronium's blood clearance (11.4+/-1.4 ml x kg(-1) x min(-1), mean +/- SD) did not vary with hemoglobin. Rapacuronium's weight-normalized pharmacokinetic parameters were not influenced by age, gender, or other covariates examined. Plasma concentrations of ORG9488 were typically less than 14% those of rapacuronium during the initial 30 min after rapacuronium administration. CONCLUSIONS: In this patient population, neither age nor gender influence elimination of rapacuronium. This finding contrasts to an age-related decrease in plasma clearance observed in a study of 10 healthy volunteers and in a pooled analysis of the pharmacokinetic data from 206 adults in multiple clinical studies. Even if ORG9488 has a potency similar to that of rapacuronium, its plasma concentrations after a single bolus dose of rapacuronium are sufficiently small to contribute minimally to neuromuscular blockade.

Brain viability and function analyzer: multiparametric real-time monitoring in neurosurgical patients.

We have developed the Brain Viability (BVA) and Brain Function (BFA) Analyzers for monitoring the following parameters from the human cerebral cortex cerebral blood flow: (CBF), NADH redox state, Electro corticography (ECoG), brain temperature, extracellular K+, DC potential and intracranial pressure (ICP). The BVA monitors the first 4 parameters only. The Brain viability probe (BVP) and Brain function multiprobe (BFM) were used during 11 operations and in 18 ICU patients, respectively. Preliminary results from the OR showed that 5 patients exhibited a typical increase in CBF in response to changes in end-tidal CO2 without a significant change in the NADH redox state. In 4 other patients no changes in CBF and NADH were observed. Two patients exhibited a "steeling response", i.e., a decrease in CBF and an increase in NADH. In 18 comatose patients monitored in the ICU, the ICP, CBF and ECoG were measured correctly in most patients, whereas NADH and K+ were more problematic. One patient exhibited a typical response, may be due to repeated cortical spreading depression cycles and an ischemic depolarization event. Continuous realtime multiparametric monitoring in neurosurgical patients is feasible and practical in the OR and the ICU. The information provided could be used as a diagnostic tool to guide the procedures or treatment given to the patients.