Scaphotrapeziotrapezoid joint loading during key pinch grip before and after trapeziometacarpal arthroplasty: a cadaver study.

In a previous cadaver study, we directly measured the load acting on the trapeziometacarpal joint for increasingly greater key pinch forces. We noted that the joint load ranges from 2 kg to 4 kg during progressively greater key pinch from 0.5 kg to 1.5 kg. Using the same experimental approach, the aim of the current study was to measure and compare the load acting on the scaphotrapeziotrapezoid joint for the same levels of isometric key pinch force, and how it changes after trapeziometacarpal arthroplasty. We performed a cadaver study using 7 fresh-frozen, unembalmed adult forearms and hands (2 right and 5 left). Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch grip (i.e., adductor pollicis, flexor pollicis longus, extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus tendons). Measurements were made inside the joint using a force-sensing resistor sensor (Tekscan® FlexiForce™ force sensor). Before the trapeziometacarpal joint surgery, median load values recorded in the scaphotrapeziotrapezoid joint were 1.2 kg (IQR, 1.0-1.4), 1.6 kg (IQR, 1.6-2.5) and 2.4 kg (IQR, 2.3-3.4) during 0.5 kg, 1 kg and 1.5 kg key pinch, respectively. After the trapeziometacarpal arthroplasty, median joint contact forces did not change significantly relative to the original configuration. Our findings indicate that the loads measured in the scaphotrapeziotrapezoid joint during a simple key pinch are in fact lower than those measured inside the trapeziometacarpal joint. After trapeziometacarpal arthroplasty, the values are similar with no increase in load, suggesting that clinically asymptomatic scaphotrapeziotrapezoid radiographic involvement may not be a contraindication to arthroplasty.

Assessment of trapezial prosthetic cup migration: A biomechanical study.

We performed a biomechanical study using 60 Sawbones® rigid foam blocks of two simulated densities (osteoporotic, n = 30 and non-osteoporotic, n = 30) and 10 cadaveric trapezium bones from fresh-frozen, unembalmed adult cadaver hands to assess the trapezial prosthetic cup migration with progressively greater compression loads (10-40 kg). Two cups from the Touch® prosthesis were compared: 9-mm conical cup and 9-mm spherical cup. Uniaxial compression tests were carried out using an MTS Criterion® Series 40 Electromechanical Testing System. Cup migration was measured in millimeters (mm) at 10, 20, and 40 kg of compression load. Median cup migration values were similar in the cadaveric trapezium bones and Sawbones® non-osteoporotic blocks, and higher in the Sawbones® osteoporotic blocks. In the cadaveric trapezium bones and the Sawbones® non-osteoporotic blocks, migration values were less than or equal to 0.1 mm for 10 and 20 kg loads; it was 0.2 mm for 40 kg load. In the Sawbones® osteoporotic blocks, migration values were less than or equal to 0.3 mm for 10 and 20 kg loads; it was 0.4-0.5 mm for 40 kg load. There was no significant difference between the two cup shapes in both cadaveric trapezium bones and Sawbones® non-osteoporotic blocks. In Sawbones® osteoporotic blocks, the largest difference between the two cup shapes was 0.1 mm for loads up to 40 kg, which corresponded to our measurement accuracy. Our findings indicate that the trapezial component of total trapeziometacarpal joint arthroplasty undergoes very weak migration for axial compression loads up to 40 kg, presumably below the threshold of clinical relevance. The cup shape did not have an obvious influence; however, low bone mineral density may result in greater cup migration.

[Epidemiology and care of myocardial infarct at the Fribourg Canton Hospital 1995]. / Epidémiologie et prise en charge de l'infarctus du myocarde à l'Hôpital cantonal de Fribourg en 1995.

PURPOSE: This study evaluates epidemiological data in a population of patients admitted for acute myocardial infarction in a large Swiss community hospital. It focuses on the application of recent drug treatment and newer therapeutic techniques. METHOD: Data acquisition was based on medical records of all patients who were admitted to the Cantonal Hospital of Fribourg in 1995. Their one-year follow-up was obtained through questionnaires sent to general practitioners. RESULTS: During the study period: 146 myocardial infarctions were diagnosed in 144 patients. Median age was 67.1 and 35% of patients were female. Nineteen percent were diabetics, 51% had hypertension and 28% had a positive family history for coronary artery disease. Active smokers made up 32%, 17% were past smokers. Myocardial infarction was anterior in 40%, inferior in 36% and non-Q wave myocardial infarction in 35%. Eighteen percent were subacute myocardial infarction. Killip class on admission were as follow: class I 65%, class II 21%, class III 1% and class IV 11%. Thrombolytic treatment was administered in 29% of patients. Vasoactive amines were used in 27% of patients and 8% were intubated some time during their hospital stay. At hospital discharge 81% were treated with Aspirin, 31% with anticoagulants, 47% with an ACE inhibitor, 38% with a beta-blocker, 34% with nitrates and 25% with a calcium antagonist. Among this population, 62% had an echocardiogram, 30% a stress test and 8% a Holter recording. Coronary angiography was performed in 52%, which revealed 33% one-vessel disease, 28% two-vessel disease, 25% three-vessel disease and 9% normal coronary arteries. Percutaneous coronary angioplasty was done in 53% of cases and a coronary stent implanted in 22%. Twelve percent had surgical revascularization. The mean hospital stay was 16.3 +/- 10.8 days, with in hospital mortality of up to 19.2% and a one-year mortality of 25.3%. CONCLUSION: Treatment modalities of patients admitted for acute myocardial infarction at the Hospital of Fribourg are comparable with literature data. Hypolipemic treatment has not been prescribed as often as recent guidelines recommend, but the use of ACE inhibitors was more common. As in other studies, older patients have the highest mortality. The absence of hospital coronarography facility did not seem to influence the prognosis of that population.

Evidence for preservation of cortical bone mineral density in patients on continuous ambulatory peritoneal dialysis.

It is still unclear whether dialysis modality, i.e., continuous ambulatory peritoneal dialysis (CAPD) versus hemodialysis (HD) specifically affects bone mineral density (BMD). To answer this question, 34 patients on HD and 25 on CAPD were matched for age, sex, height, and body weight with 125 normal subjects. BMD was measured using dual-energy X-ray absorptiometry (DXA; Hologic QDR 1000/W) at the lumbar spine (trabecular bone), the femoral neck (mixed cortical and trabecular bone), the distal tibial diaphysis (cortical bone), and the epiphysis (trabecular bone) in all subjects. No significant difference for blood hemoglobin, albumin, total and ionized calcium, intact parathyroid hormone (PTH) or phosphorus concentrations, as well as for alkaline phosphatase activity, failed renal allograft, prior steroid therapy, prior parathyroidectomy, duration of uremia, or of dialysis was found between patients on HD and those on CAPD. However, the residual daily urine volume and renal function at the time of the absorptiometry were higher in CAPD than in HD patients (p < 0.05) as well as the mean dialysate calcium concentration during dialysis, the blood bicarbonate concentration, and the residual renal function at the initiation of dialysis (p < 0.01, p < 0.05, and p < 0.005, respectively). In contrast, the total dose of calcium carbonate was lower in CAPD than in HD patients (p < 0.01). Results of BMD were expressed as Z scores (the number of standard deviations from the appropriate mean of BMD of 623 healthy subjects adjusted for age and sex). At the lumbar spine, no significant difference with respect to BMD was observed between the three groups. At the femoral neck and tibial epiphysis, HD patients had lower BMD (p < 0.001) than normal controls, whereas no difference was observed between HD and CAPD patients. At tibial diaphysis, patients on HD had lower BMD (p < 0.001) than patients on CAPD and than normal controls, with the values being similar in patients on CAPD and in normal controls. The results remained identical after exact matching of HD (n = 25) and CAPD (n = 25) patients for dialysis duration (1.9 +/- 0.3 and 1.7 +/- 0.3 years, respectively). Multiple regression analysis revealed significant negative correlations between Z scores at the lumbar spine (p < 0.05), femoral neck (p < 0.02), tibial diaphysis (p < 0.005), and tibial epiphysis (p < 0.05) on the one hand and plasma alkaline phosphatase activity on the other. The Z score at tibial diaphysis was also correlated with residual renal function at the initiation of dialysis (p < 0.05). In conclusion, this study provides evidence for the preservation of cortical bone with CAPD as opposed to HD. The higher residual renal function observed in the former treatment modality might account, at least in part, for this finding.

[Constitutional stereotyped gap in human chromosomes (author's transl)]. / Lacune stéréotypée constitutionnelle des chromosomes humains.

The stereotyped break with gap of a chromosomal variant is rarely observed. This anomaly is transmitted according to autosomal dominant rule. The distal part of the broken chromosome may either be still bound to the sister chromatid through mitotic non-disjunction, forming a triradial figure, or take a moniliform and pulverized appearance, evoking premature chromosome condensation.

[Antisocial behaviour and variations in length of Y chromosome (author's transl)]. / Conduite antisociale et longueur du chromosome Y

The length of they chromosome has been measured for 50 male criminals in a psychiatric security hospital and for 50 non criminal control men. The distribution was normal for the 2 populations and there was no significant difference between the mean Y/F, Yf/Y values and the number of brightly fluorescent segments. For criminal psychopaths, there was no close correlation between the size of the Y chromosome and the psychiatric or criminal background.