Acetabular cup wear in total hip arthroplasty

Clinical, pathologic, radiographic, and biomechanical factors of 10 severely worn retrieved Charnley acetabular cups were examined to determine whether these factors influenced cup wear. Change in cup thickness was found to be linear with time. It was found that the actual change in cup thickness was not significantly different from the radiographic change in cup thickness. No correlation was found with the other clinical or radiographic factors.

A fifteen-year follow-up study of one hundred Charnley low-friction arthroplasties

This two-part study concerns the fate of 100 Charnley low-friction arthroplasties performed in 92 patients at The Hospital for Special Surgery. The first part of the study is a clinical and radiographic evaluation of the 40 hips that were available for follow-up at an average of 15.3 years after surgery. The second part is a survival analysis of the arthroplasty, the individual components, and the patients, using data from all 100 arthroplasties. The authors conclude that the vast majority of older patients who undergo cemented total hip arthroplasty will not require a subsequent arthroplasty, and will have satisfactory pain relief for the remainder of their lives.

The nine- to fifteen-year follow-up of one-stage bilateral total hip arthroplasty

Careful selection and preoperative evaluation of patients with bilateral hip disease for one-stage bilateral total hip arthroplasty can yield satisfactory results consistent with those published for unilateral hip disease. These patients are generally younger and more active than patients undergoing unilateral total hip arthroplasty and require meticulous attention to both technique and prosthetic design. The authors found that the Charnley design remains the gold standard against which other prostheses must be measured in the long-term follow-up.

One-stage bilateral total hip arthroplasty. A prospective study of perioperative morbidity

Controversy exists over the safety of performing one-stage bilateral total hip arthroplasty. A prospective protocol was established in 35 patients to evaluate the perioperative morbidity of one-stage bilateral arthroplasty as compared with unilateral controls. Although there was no increase in the frequency of respiratory morbidity in bilateral procedures, respiratory depression is common with both procedures. The authors believe this is consistent with varying degrees of the adult respiratory distress syndrome and that the term fat embolism syndrome is misleading and should be abandoned.

Renal cell culture

Methods for the establishment and growth of renal cell types in culture are reviewed, with emphasis on current trends. General techniques available for the isolation and culture of glomerular cells have progressed from explant to enzyme dissociation and cloning techniques. The growth characteristics and properties of cultured glomerular endothelial, epithelial, mesangial, and bone-marrow-derived cells are discussed. Studies are described in which cultures of contractile mesangial cells have led to an elucidation of their role both in normally functioning glomeruli and in disease states. Renal tubule culture techniques also have progressed from mixed tissue explants and cell isolates to fractionation of enriched tubule populations and growth of specific, individually microdissected proximal convoluted, proximal straight, thick ascending limb of Henle's loop, and collecting tubules. The differentiated tubule epithelial-specific properties of such primary cultures are discussed in relation to those of permanently growing cell lines such as MDCK and LLC-PK1. Renal tubule cultures will be invaluable for the study of the role of hormones and extracellular matrix in epithelial growth and polarity of normal structure and function. In addition, in vitro models of cultured renal tubules have been established to study the effects of age, nephrotoxins, and anoxic injury.

Results of acetabular revisions with newer cement techniques

It is the purpose of this article to evaluate the authors' results of cemented acetabular reconstructions in revision surgery for massive osseous deficiencies with the previously stated techniques. In addition, the authors will examine the results with respect to bone allografting and bone autografting and their compatibility with methyl methacrylate.

Fracture of the femoral component. Analysis of failure and long-term follow-up of revision

Although fracture of the femoral component is an uncommon mode of mechanical failure, when it does occur, symptoms may be dramatic. In addition, it presents the surgeon with one of the more challenging problems in revision total hip arthroplasty surgery. This study reviews the problem of femoral stem fracture and evaluates the stem failures and long-term follow-up of the revision for femoral component fractures performed at The Hospital for Special Surgery.

Single-scan Bayes estimation of cerebral glucose metabolic rate: comparison with non-Bayes single-scan methods using FDG PET scans in stroke

Three single-scan (SS) methods are currently available for estimating the local cerebral metabolic rate of glucose (LCMRG) from F-18 deoxyglucose (FDG) positron emission tomography (PET) scan data: SS(SPH), named for Sokoloff, Phelps, and Huang; SS(B), named for Brooks; and SS(H), named for Hutchins and Holden et al. All three of these SS methods make use of prior information in the form of mean values of rate constants from the normal population. We have developed a Bayes estimation (BE) method that uses prior information in the form of rate constant means, variances, and correlations in both the normal and ischemic tissue populations. The BE method selects, based only on the data, whether the LCMRG estimate should be computed using prior information from normal or ischemic tissue. The ability of BE to make this selection gives it an advantage over the other methods. The BE method can be used as a SS method or can use any number of PET scans. We conducted Monte Carlo studies comparing BE as a SS method with the other SS methods, all using a single scan at 60 min. We found SS(H) to be strongly superior to SS(SPH) and SS(B), and we found BE to be definitely superior to SS(H).

Use of classification of primary obstetric factors in perinatally related mortality surveillance

The use of a classification of the primary obstetric factors leading to death for all fetal and neonatal losses that occurred between 20 weeks gestation and 28 days after birth is described. This is defined as the 'total perinatally related loss', and is compared with the information obtained if enquiry is limited to the traditional 'perinatal' period, from 28 weeks gestation to 7 days after birth. Both centre-based data for Queen Mary Hospital, Dunedin, and population-based data for the geographic area of the Otago Hospital Board for the four year period from September 1982 until August 1986 are reported. Spontaneous prematurity was the major factor responsible for these deaths, and its importance would not have been appreciated if the perinatal period alone had been analysed. The need for standardised classification of perinatally related deaths for epidemiological monitoring is discussed.

Twenty-four-hour ambulatory blood pressure in normotensive adolescent children of hypertensive and normotensive parents

Twenty-four-hour ambulatory blood pressure measurements were obtained during usual daily activities from two groups of normotensive adolescents: Cases had at least one hypertensive parent, and controls had both parents normotensive. Automatic measurements were programmed at 7.5-minute intervals. For each subject, within each of three time periods, the data were summarized by descriptors of the frequency distribution and the frequency spectrum. The time periods were sleep, school hours, and other waking hours. Regression analyses examined the relation between the blood pressure monitoring descriptors and case-control status adjusted for non-blood-pressure variables found to relate to case-control status. In stepwise logistic regression analysis with case-control status as the dependent variable, it was found that the mean level of diastolic pressure during school hours was significant, whereas the standard resting measurement was not. In linear regression analyses with blood pressure monitoring descriptors and standard resting measurements as dependent variables, several monitoring descriptors were found to be significantly related to the interaction between case-control status and certain variables that can affect blood pressure, such as weight and the presumed stress of school; no such relations were found for the standard resting measurements. These findings demonstrate the superiority of the ambulatory monitoring variables over the standard resting measurements in studying case-control differences.

Metallic wear in failed titanium-alloy total hip replacements. A histological and quantitative analysis

We conducted extensive histological examination of the tissues that were adjacent to the prosthesis in nine hips that had a failed total arthroplasty. The prostheses were composed of titanium alloy (Ti-6Al-4V) and ultra-high molecular weight polyethylene. The average time that the prosthesis had been in place in the tissue was 33.5 months (range, eleven to fifty-seven months). Seven arthroplasties were revised because of aseptic loosening and two, for infection. In eight hips cement had been used and in one (that had a porous-coated implant for fifty-two months) no cement had been utilized. Intense histiocytic and plasma-cell reaction was noted in the pseudocapsular tissue. There was copious metallic staining of the lining cells. Polyethylene debris and particles of cement with concomitant giant-cell reaction were present in five hips. Atomic absorption spectrophotometry revealed values for titanium of fifty-sic to 3700 micrograms per gram of dry tissue (average, 1047 micrograms per gram; normal, zero microgram per gram), for aluminum of 2.1 to 396 micrograms per gram (average, 115 micrograms per gram; normal, zero micrograms per gram), and for vanadium of 2.9 to 220 micrograms per gram (average, sixty-seven micrograms per gram; normal, 1.2 micrograms per gram). The highest values were found in the hip in which surgical revision was performed at fifty-seven months. The concentrations of the three elements in the soft tissues were similar to those in the metal of the prostheses. The factors to which failure was attributed were: vertical orientation of the acetabular component (five hips), poor cementing technique on the femoral side (three hips), infection (two hips), and separation of a sintered pad made of pure titanium (one hip). A femoral component that is made of titanium alloy can undergo severe wear of the surface and on the stem, where it is loose, with liberation of potentially toxic local concentrations of metal debris into the surrounding tissues. It may contribute to infection and loosening.

The probability that long-term mean diastolic blood pressure is extreme: tables for black individuals

With use of a large data base and a statistical model for diagnosis developed earlier, we have constructed the among-individual conditional distribution of the long-term mean diastolic blood pressure, md, of an individual, given the means of several measurements of systolic and diastolic blood pressure on the individual. Using this conditional distribution we provide tables and a simple algorithm for computation of the conditional probability that md for an individual exceeds a specified value (for example, 90 mmHg), given the measured values of systolic and diastolic pressure.

Correcting for selection bias in estimation of within-individual variance

Consider a variable whose expected value distributes among individuals in a population, and which also has an important component of within-individual variance. In a screening study that involves repeated observations only for those individuals whose initial observation exceeds an arbitrary cutoff point, the usual estimator of within-individual variance is biased. Assuming normality and independence, this note gives the derivation of the expected value of the estimator and uses it to obtain an unbiased estimator. The results generalize to the bivariate case that involves selection on only one variable of the pair. A companion paper provides an example with use of blood pressure.

Autoregressive growth curves and Kalman filtering

The first part of this paper describes how a Kalman filter can be used to construct maximum likelihood (ML) estimates of autoregressive (AR) and polynomial parameters in polynomial growth curves with AR-1 errors and irregularly-spaced data. The second part introduces a disturbed highest derivative polynomial (DHDP) as a model for growth curves. This model does not depend on regression coefficients. Variances of the highest derivative disturbance and the observation error are estimated (by ML) using a Kalman filter. The estimated DHDP growth curve is obtained by optimally smoothing the output of the filter. Equally spaced data is not required. The DHDP model and analysis are developed for an individual and extended to a population growth curve using data from many individuals with covariates.

Revision total hip arthroplasty. Current role of polymethylmethacrylate

In 29 consecutive failed total hip arthroplasties revised during a 15-month period, cement fixation was used in 14 and cementless fixation in 11. A combination of the two techniques was used in four patients. Analysis of the indications for one or the other fixation type showed that the quality of bone stock and the location of bone deficiency were the most important criteria. The use of a fixation technique that suited the method of bone repair, i.e., autografts, allografts, or a combination of the two, was all-important. Cement technique alone was generally used when bone stock was intact and healthy. Cement was also used in combination with protrusio screens and allografts for gross acetabular deficiencies. Cementless, porous ingrowth technique, together with autografts, was preferred for femoral deficiencies or minor acetabular deficiencies. Bipolar prostheses with compressed, fragmented allografts were used as salvage procedures in gross acetabular deficiencies in older patients, especially when the femoral component did not need to be exchanged.

The development of neurons in the cat perigeniculate nucleus and reticular nucleus of the thalamus

The postnatal development of soma size and cytochrome oxidase activity was examined in the perigeniculate nucleus (PGN) and reticular nucleus of the thalamus (RNT). Neurons in the PGN and RNT exhibited a rapid increase in soma size between 2 and 4 weeks of age. During this period of cell growth there is an increase in the intensity of cytochrome oxidase staining within the cell body. Cells in both the PGN and RNT decrease in size after 4 weeks of age, and become very fusiform in shape. During this postnatal period, there is also a shift in cytochrome oxidase staining from the cell body to the dendrites.

The development of soma size changes in the C-laminae of the cat lateral geniculate nucleus following monocular deprivation

This study examined the pattern of soma size changes in the cat dorsal lateral geniculate nucleus (dLGN) from 4 weeks of age to adulthood following monocular lid suture at two weeks of age. Different patterns of soma size changes were found between the A-laminae and C-laminae. In layers A, A1, and C significant soma size differences were found between the deprived and non-deprived laminae by 4 weeks of age. However, the magnocellular portion of layer C was affected more by deprivation than the parvocellular portion. Layer C1 did not reveal significant soma size changes until 20 weeks of age. Layer C2 did not exhibit any soma size changes at any age. These differential responses to monocular deprivation suggest different time courses of development among the dLGN laminae.

Treatment with oral piperazine oestrone sulphate for genuine stress incontinence in postmenopausal women

The use of oestrogens in the treatment of genuine stress incontinence was assessed by a double-blind prospective trial in 36 postmenopausal women with genuine stress incontinence who received 3 months of cyclical treatment with either piperazine oestrone sulphate or a matching placebo. Patients were assessed subjectively and objectively before and after treatment by 7-day bladder charts, urethral pressure profiles (UPP), the Urilos nappy test, vaginal cytology and hormone assays (plasma oestrogens and gonadotrophins). There was no statistical difference in the subjective response to treatment between the two groups. After 6 weeks of treatment there was a greater reduction in the number of pad changes/24 h in the oestrogen-treated patients that approached statistical significance but, because of a marked response in the placebo group, this difference was not significant after 3 months of treatment. There were also no significant differences between the two groups with respect to the UPP or Urilos measurements but the vaginal cytology and hormone profiles were significantly affected by oestrogens. In view of the possible risks of oestrogen therapy its use in genuine stress incontinence is limited.

Cardiac and noncardiac malformations: observations in a population-based study

A regional case-control study of congenital cardiovascular malformations (CCVMs) searches for all live-born infants in the community in whom the cardiac diagnosis has been confirmed by echocardiography, cardiac catheterization, surgery, or autopsy. Their families are studied in comparison to those of a representative sample of resident live-born infants. Detailed descriptions of noncardiac abnormalities are obtained from physician reports and maternal interviews expanded by medical record and death certificate data. Among 1,494 cases and 1,572 controls, chromosomal abnormalities, syndromes, heritable disorders, and suspect syndromes occurred with an overwhelming excess in cases (chromosomes, P less than 10(-4); syndromes/heritable disorders, P less than .005). Abnormalities affecting chromosomes 13, 18, and 21 constituted 93% of the cytogenetic defects. Syndromes and heritable disorders were of 39 types. Nonsyndromic abnormalities were three times more frequent in cases than in controls (P less than .005). Case excesses occurred for central nervous system malformations, eye disorders, major abdominal wall defects, and abnormalities of the alimentary and urinary tracts. Severe anomalies frequent among cases were those which also occur in certain recognized syndromes, and it is suggested that paired combinations of cardiac and other midline anomalies may represent "formes frustes" of syndromes with similar though variable phenotypic expressions. Cleft lip and palate, inguinal hernia, and lower limb anomalies occurred with equal frequency, suggesting their association with CCVMs by chance alone.

An objective assessment of physiotherapy for female genuine stress incontinence

Sixty women with genuine stress incontinence were consecutively assigned to one of four physiotherapy groups who were treated for 6 weeks by either (1) pelvic floor exercises (PFE) in hospital; (2) PFE and faradism; (3) PFE and interferential therapy; (4) PFE at home. Assessment before and after treatment was by 7-day bladder charts, urethral pressure profiles and perineometry. Approximately two-thirds of the hospital-treated patients (groups 1, 2 and 3) experienced marked or moderate subjective improvement and at 6 months, 27% were dry or almost dry. There was little difference in outcome between groups 1, 2 and 3 but hospital-based therapy was more effective than home treatment. Statistical analyses showed that there were significant improvements in the objective indices measured in the 45 hospital-treated patients. Successful treatment was more likely in younger patients, in those with lesser degrees of genuine stress incontinence and those who had had no previous pelvic floor surgery.

The role of lysosomal enzymes in killing of mammalian cells by the lysosomotropic detergent N-dodecylimidazole

The sensitivity of cultured human and hamster fibroblast cells to killing by the lysosomotropic detergent N-dodecylimidazole (C12-Im) was investigated as a function of cellular levels of general lysosomal hydrolase activity, and specifically of cysteine cathepsin activity. Fibroblasts from patients with mucolipidosis II (I-cell disease) lack mannose-6-phosphate-containing proteins, and therefore possess only 10-15% of the normal level of most lysosomal hydrolases. I-cell fibroblasts are about one-half as sensitive to killing by C12-Im as are normal human fibroblasts. Overall lysosomal enzyme levels of CHO cells were experimentally manipulated in several ways without affecting cell viability: Growth in the presence of 10 mM ammonium chloride resulted in a gradual decrease in lysosomal enzyme content to 10-20% of control values within 3 d. Subsequent removal of ammonium chloride from the growth medium resulted in an increase in lysosomal enzymes, to approximately 125% of control values within 24 h. Treatment with 80 mM sucrose caused extensive vacuolization within 2 h; lysosomal enzyme levels remained at control levels for at least 6 h, but increased 15-fold after 24 h of treatment. Treatment with concanavalin A (50 micrograms/ml) also caused rapid (within 2 h) vacuolation with a sevenfold rise in lysosomal enzyme levels occurring only after 24 h. The sensitivity of these experimentally manipulated cells to killing by C12-Im always paralleled the measured intracellular lysosomal enzyme levels: lower levels were associated with decreased sensitivity while higher levels were associated with increased sensitivity, regardless of the degree of vacuolization of the cells. The cytotoxicity of the cysteine proteases (chiefly cathepsin L in our cells) was tested by inactivating them with the irreversible inhibitor E-64 (100 micrograms/ml). Cell viability, protein levels, and other lysosomal enzymes were unaffected, but cysteine cathepsin activity was reduced to less than 20% of control values. E-64-treated cells were almost completely resistant to C12-Im treatment, although lysosomal disruption appeared normal by fluorescent visualization of Lucifer Yellow CH-loaded cells. It is concluded that cysteine cathepsins are the major or sole cytotoxic agents released from lysosomes by C12-Im. These observations also confirm the previous conclusions that C12-Im kills cells as a consequence of lysosomal disruption.

The microscopic anatomy of the bone-cement interface in failed total hip arthroplasties

Thirty specimens were removed from the bone-cement interface in 25 hips revised for aseptic loosening of total hip arthroplasty. Histologic examination of the membranous tissues revealed that histiocytosis, fibrosis, and necrosis were present in every specimen. Other prominent features included particles of acrylic cement, polyethylene debris, and fragments of necrotic bone. Mechanical failure was characterized by cement fractures, and microfracture of bone. The presence of cement debris and bone detritus in the membranes, and smooth appearance of the removed cement mantles substantiated the presence of mechanical failure. The process of loosening was characterized by the recruitment of histiocytes into the interface and the subsequent resorption of bone around the prosthesis. This may be a manifestation of the rate of cement wear and tear, particle size, and the immunologic predispositions of the host. These observations on interfaces of loosened prostheses are reexamined and reinterpreted in the light of radiologic observations on interface radiolucent zones and well-functioning prostheses.