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Selective serotonin reuptake inhibitors (SSRIs) are among the most commonly prescribed medications. They are among the first-line medications for several chronic or relapsing-remitting psychiatric conditions, including major depressive disorder and anxiety disorders. The advantages of SSRI use include ease of titration and their tolerability and safety profile. Guidelines for the short-term use of SSRIs are widely available, but there is no well-organized guidance on how and whether to maintain a patient on SSRIs for the long-term. In this article, we discuss the benefits and possible adverse consequences of long-term SSRI use, as well as clinical practice considerations when using SSRIs chronically. The major benefit of long-term SSRI use is relapse prevention. The current literature suggests that the general health risks of long-term SSRI use are low; however, further research, particularly in special populations including youth and the elderly, is needed. Long-term SSRI use increases the risk of tachyphylaxis and discontinuation syndrome. Recognizing that many patients may remain on SSRIs for many years, there are several factors that prescribers should consider if they choose to use an SSRI when initiating treatment and during long-term monitoring. The decision to continue or to discontinue an SSRI should be an active one, involving both the patient and prescriber, and should be revisited periodically. Patients who remain on SSRIs for the long-term should also have periodic monitoring to reassess the risk-benefit ratio of remaining on the SSRI, as well as to assess the safety, tolerability, and efficacy of the medication. more...

Pharmacogenomic testing in clinical psychiatry has grown at an accelerated pace in the last few years and is poised to grow even further. Despite robust evidence lacking regarding efficacy in clinical use, there continues to be growing interest to use it to make treatment decisions. We intend this article to be a primer for a clinician wishing to understand the biological bases, evidence for benefits, and pitfalls in clinical decision-making. Using clinical vignettes, we elucidate these headings in addition to providing a perspective on current relevance, what can be communicated to patients, and future research directions. Overall, the evidence for pharmacogenomic testing in psychiatry demonstrates strong analytical validity, modest clinical validity, and virtually no evidence to support clinical use. There is definitely a need for more double-blinded randomized controlled trials to assess the use of pharmacogenomic testing in clinical decision-making and care, and until this is done, they could perhaps have an adjunct role in clinical decision-making but minimal use in leading the initial treatment plan. more...

Over the past decade, concussion has become the most widely discussed injury in contact sports. However, concussions also occur in several other settings, such as non-contact sports, elderly individuals, young children, military personnel, and victims of domestic violence. Concussion is frequently undiagnosed as a cause of psychiatric morbidity, especially when the patient has no history of loss of consciousness or direct head trauma. Almost all of the extant literature focuses on traumatic brain injury and assumes that concussion is merely a mild form of traumatic brain injury, which has resulted in a lack of understanding about what concussion is, and how to diagnose, monitor, and treat its varied neuropsychiatric symptoms. In this Review, we address key issues so that the psychiatric clinician can better understand and treat patients with a clinical phenotype that might be the direct result of, or be exacerbated by, concussion. Future research needs to focus on prospective clinical trials in all affected patient populations (ie, those affected by concussion and those affected by various degrees of traumatic brain injury), the identification of reliable biomarkers that can be used to assist with diagnosis and treatment response, and the development of effective treatment interventions. Clearly differentiating concussion from traumatic brain injury is essential to achieve reliable and clinically relevant outcomes. more...

Bone repair is regulated by biological factors and the local mechanical environment. We hypothesize that the combined use of low-intensity pulsed ultrasound (LIPUS) and recombinant human bone morphogenetic protein-2 (rhBMP-2) will synergistically or additively enhance bone regeneration in a model simulating the more difficult scenarios in orthopaedic traumatology. more...

The relationship between knee pain and radiographic evidence of knee osteoarthritis (OA) is notoriously imperfect. In particular, conditions that distinguish individuals with symptoms from those with comparable radiographic involvement who remain asymptomatic are unclear. We investigated dynamic loading across the knee in individuals with mild radiographic OA who were distinguished by the presence or absence of knee pain.Subjects were recruited into 3 groups: symptomatic with a Kellgren/Lawrence (K/L) grade of 2 (n = 52), asymptomatic with a K/L grade of 2 (n = 19), and asymptomatic with a K/L grade of 0 or 1 (n = 37), the latter representing a normal comparator group. Dynamic knee loading was assessed with gait analysis, and both the peak external knee adduction moment and the knee adduction angular impulse were determined.Peak knee adduction moment and knee adduction angular impulse were 19% and 30% higher, respectively, in symptomatic K/L grade 2 individuals than in asymptomatic individuals with the same radiographic grade (P < 0.05). Conversely, the asymptomatic K/L grade 2 group did not differ from the K/L grade 0–1 normal comparator group (P = 1.00).Among individuals with mild radiographic knee OA (K/L grade 2), those who are symptomatic have significantly higher medial compartment loads than those who are asymptomatic, whereas those who are asymptomatic do not differ from normal controls (asymptomatic K/L grade 0 or 1). These findings suggest a biomechanical component to the distinction between asymptomatic and symptomatic radiographic OA, which may be pathophysiologically important. more...

Articular cartilage is a thin heterogeneous tissue (typical thickness of less than 2 mm) composed of collagen, proteoglycan, and water that coats skeletal joint surfaces. Its physical and chemical integrity are essential for maintaining normal joint articulation. MR imaging techniques are being developed to visualize articular cartilage for the purpose of assessing changes in its structure that occur with age and the onset of joint disease. Emerging high‐field MR systems (greater than 4 T) have a higher signal‐to‐noise ratio, which can be used to improve the spatial resolution for imaging articular cartilage beyond that available in most clinical systems. In this study, we examined the effect of changing the proteoglycan content of articular cartilage on high‐resolution (40 × 40 × 100 μm) T1‐ and T2‐weighted images acquired at 11.74 T (500 MHz for protons). Susceptibility artifacts were observed near the cartilage‐bone interface that were verified by separating the cartilage from the bone. MR image heterogeneity of articular cartilage was observed as a function of depth and in the transverse directions of the sample. Enzymatic depletion of cartilage proteoglycan demonstrated that the MR image heterogeneity is due in part to variation of the proteoglycan content in different regions of the cartilage. The apparent diffusion coefficient (ADC) was measured as a function of depth in the cartilage. The ADC varied from the subchondral bone to the articular surface for both normal and digested cartilage. In addition, the ADC increased by 20% after 6 hours of enzymatic digestion of proteoglycan. These results suggest a role for high‐field MRI of articular cartilage in the management and staging of osteoarthritis and other joint diseases. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 23B: 33–43, 2004 more...

Introduction: Nocturnal enuresis is a condition in which children at least 5 years of age are incontinent of urine at night. Atomoxetine, a potent inhibitor of the presynaptic norepinephrine transporter, is used to treat attention-deficit/hyperactivity disorder (ADHD). This study tested the hypothesis that atomoxetine will provide significant therapeutic benefit for nocturnal enuresis in patients with the diagnosis of nocturnal enuresis.Methods: Atomoxetine's efficacy for improving nocturnal enuresis was studied in 87 pediatric subjects using an outpatient, multicenter, randomized, double-blind, parallel, placebo-controlled study. Efficacy was determined by measuring the mean number of dry nights per week using an intent-to-treat analysis of the primary outcome measure, the Dry Night Log-Parent Report (DNL-PR), a daily parent diary.Results: Baseline and end point DNL-PR data were available from 42 atomoxetine-treated and 41 placebo-treated subjects. Atomoxetine increased the average number of dry nights per week by 1.47 compared with .60 for placebo (F = 7.06; df = (1, 75); p = 0.01). Fifteen atomoxetine-treated subjects (35.7%) had an increase of at least 2 dry nights per week compared with only 6 (14.6%) placebo-treated subjects (Fisher's exact test; p = 0.042). There were no significant differences in adverse events between the groups.Conclusions: Compared with placebo, atomoxetine treatment was associated with a significant increase in dry nights in children with nocturnal enuresis. more...

The objectives of the present study were to examine clonidine use before and after initiation of atomoxetine in a cohort of children with attention deficit/hyperactivity disorder (ADHD). For this purpose, medical and pharmaceutical claims data for patients from 75 managed health care plans across the United States were extracted to identify a cohort of patients aged 18 years and younger at the time of a first atomoxetine prescription. Clonidine users were characterized on the basis of demographics, comorbid conditions, medication use and provider types, and prescribing patterns before and after the index atomoxetine prescription assessed. Subgroups of patients switching from clonidine to atomoxetine were examined and predictors of ongoing or new clonidine use were assessed. Of patients filling a first prescription for atomoxetine, 9.6% received a prescription for clonidine at some time and 4.3% within the previous 2 months. Children identified with a hyperactive component to their ADHD, those with more complex diagnostic histories, and those with tics and sleep disorders were particularly likely to receive clonidine. More than a third of patients (36.5%) with recent clonidine use subsequently discontinued use, with the pattern of clonidine use before and after atomoxetine use being highly dependent upon the pattern of stimulant prescription. Atomoxetine, in some cases, seems to have replaced clonidine in the treatment of patients with ADHD complicated with comorbid psychiatric disorders. In others, atomoxetine has replaced both stimulant and clonidine in patients previously requiring this combination for the control of symptoms or for the management of stimulantrelated adverse effects. more...

Gap regions between a bone and an implant, whether existing upon insertion or developing over time, can lead to implant failure. Currently, planar x-ray imaging and CT are the most commonly used methods to evaluate the gap region. An alternative to these available clinical imaging modalities could help to better evaluate bone resorption. Previous experiments with diffraction enhanced imaging (DEI) have shown significant contrast advantages over monochromatic synchrotron radiation (SR) imaging. DEI and planar SR radiography images of bone samples with drill holes and gap regions of known geometry were acquired at the NSLS beamline X15A (Upton, NY, USA). The images acquired with DEI show measurable contrast-to-noise gains when compared to the images acquired using SR radiography. more...

The aim of this study was to quantify bone microarchitecture within the glenoid fossa and mandibular condyle following mandibular distraction osteogenesis. Eight 6- to 9-month-old male beagle dogs underwent bilateral vertical mandibular distraction with semiburied distractors (12 days of distraction at 1 mm per day). One unoperated animal served as control. After distraction the animals were divided into two groups (N = 4) and killed after 1 or 2 months of consolidation. Three-dimensional trabecular architecture was analyzed by micro-computed tomography (CT). At both sites the overall trends were similar. In the glenoid fossa, there was decreased bone volume, trabecular number, and connectivity density and increased trabecular separation at 1 month and decreased trabecular thickness and increased structure model index compared with the control (P < 0.05). In the mandibular condyle, there was decreased bone volume, trabecular number, and connectivity density at both 1 and 2 months, with decreased trabecular thickness and increased structure model index at 2 months only compared with the control (P < 0.05). The bone became less dense and more rodlike. These bone changes are similar to those seen by the effects of aging or impaired normal function. Thus, in the short term, changes occur in the bone microstructure of the glenoid fossa and mandibular condyle after vertical mandibular ramus distraction in the canine model. more...

Mandibular ramus height restoration by distraction osteogenesis (DO) is a key procedure in mandibular hypoplasia reconstruction. The objective of this study was to evaluate short-term skeletal changes in the regenerated bone after vertical mandibular ramus DO using a buried distraction device. Eight subadult beagle dogs underwent bilateral vertical mandibular ramus DO. After a 7-day latency period, distraction was performed at a rate of 0.5 mm twice a day for 12 days. Four dogs were killed at 1 month and four dogs at 2 months after the end of distraction. One intact beagle was included as an unoperated control. After sacrifice, micro computed tomography (μCT) and mechanical testing of distracted sites were used to measure bone volume (BV), total volume (TV), and mechanical peak load strength, respectively. The μCT images showed wide variation in the response, with some animals demonstrating considerable bone formation and reconstitution of the canal for the inferior alveolar nerve. Quantitatively, BV was no more than 67% and BV/TV was less than 25% of the intact control, and strength was approximately 33% of the intact control value. The 1 and 2 month values were similar. These results suggest that internal distractors can successfully reconstitute bone but that the regenerated tissue did not regain structural and mechanical characteristics of native bone within the 2 month study period. more...

Osteoarthritis is a disease of synovial joints that involves articular cartilage breakdown with accompanying bone changes, including subchondral sclerosis and osteophytosis. However, conflicting data have been reported concerning the cause-and-effect relationship, if any, between these changes. The authors studied the subchondral plate (subchondral bone plus calcified cartilage) in relation to the degree of articular cartilage degeneration on the distal articular surface of the first metatarsal, a region prone to osteoarthritis. No correlation was found between subchondral plate thickness or porosity and the degree of cartilage degeneration in the study sample of 96 metatarsals. Owing to the suggestion that initiation of cartilage fibrillation may be a result of steep stiffness gradients in the subchondral bone, the ratios of subchondral plate thickness in adjacent regions of the metatarsal head were examined in detail, but no correlation was found with subchondral degeneration. Thus increases in subchondral bone thickness are not associated with increases in cartilage degeneration on the first metatarsal, which may imply that subchondral bone changes do not cause osteoarthritis in this joint. (J Am Podiatr Med Assoc 93(2): 104-110, 2003) more...

Concentrations of the bone resorption markers pyridinoline and deoxypyridinoline and the bone formation marker osteocalcin were measured in 24‐h urine collections from 30 subjects who underwent unilateral total hip replacements for monoarticular symptomatic osteoarthrosis and 10 controls. The patient groups were divided based on the femoral implant type (cemented cobalt alloy stem, cementless porous coated cobalt alloy stem, and cementless porous coated titanium alloy stem). Urine collections were performed before surgery and then at 3, 6, 12, 24, and 36 months. There were significant changes over time in the three patient groups for pyridinoline, deoxypyridinoline, and the ratio of osteocalcin to deoxypyridinoline (p≤ 0.01), but the control group values did not change over time. The resorption markers tended to peak at 3 months and the osteocalcin to deoxypyridinoline ratio was more variable, having depressed values in the cementless cobalt alloy group and elevated values in the other two groups compared with baseline. The cementless cobalt alloy group had higher resorption marker levels than the cemented cobalt alloy group at 6, 12, 24, and 36 months and higher levels than the cementless titanium alloy group at all postoperative times (p< 0.05). The osteocalcin to deoxypyridinoline ratio was lower in the cementless cobalt alloy group than in the cemented cobalt alloy group at 3, 6, and 24 months and the cementless titanium alloy group at 6, 12, and 24 months (p< 0.05). For the cemented cobalt chrome group, the baseline‐normalized resorption marker values at 3 months and 6 months were correlated with the severity of radiographically assessed bone loss at 36 months (0.749 < r< 0.840; p< 0.05). For the cementless titanium alloy group, baseline‐normalized osteocalcin/deoxypyridinoline ratios at 3 months and 6 months were related inversely to radiographic bone loss at 36 months (0.687 < r< 0.749; p< 0.05). Thus, body fluid markers of bone metabolism change after total hip replacement. In addition, the changes in the marker concentrations were sensitive to implant design and were correlated with subsequent stress‐shielding‐induced bone loss. more...

Broiler production is increasing rapidly in the Southern Coastal Plain, and little research has been conducted to evaluate broiler litter applications on the sandy soils of the region. We conducted a 4‐yr field study to determine optimum rates of broiler litter, its economic value, changes in soil tests to a depth of 90 cm, and effects on pathogens and nematodes. Summer crops were cotton (Gossypium hirsutumL.), pearl millet [Pennisetum glaucum(L.) R. Br.] for grain, and peanut (Arachis hypogaeaL.). Winter crops were wheat (Triticum aesitivumL.) and oilseed canola (Brassica napusL.). Litter rates were 0, 4.5, 9.0, and 13.5 Mg ha−1for each crop. Litter application increased yields of cotton, pearl millet, wheat, and canola and decreased yield of peanut. Average crop value increase from application of a megagram of broiler litter was estimated to be $42 ha−1yr−1when the application was made to all crops and $68 ha−1yr−1when none was applied to peanut. The mean cost of applied litter was approximately $12 Mg−1. Surface soil P, K, Cu, Zn, and Mn were increased in direct relation to litter rate. Data indicate that it would be prudent to limit applications to about 4.5 Mg ha−1. Litter applications had little effect on soil nematodes, but Rhizoctonialimb rot (Rhizoctonia solaniAG‐4) of peanut increased. Lodging of canola, due to Sclerotiniaspp., was doubled by any application of broiler litter. more...

Radiostereometric analysis (RSA) is used to measure translations of joint replacement components with respect to the host bone in vivo. We used two cadaveric models of hip arthroplasty, one human and one canine, to evaluate the accuracy and precision of RSA‐based estimates of translations of the femoral component with respect to the femur under ideal conditions. The femoral components were attached rigidly to a micrometer stage that provided standard displacements in increments of 25 and 50 μm in the interval from zero to 500 μm along three orthogonal axes. Radiostereometric examinations were performed for each increment. Accuracy was calculated as the 95% prediction intervals from regression analyses between the measured and actual displacements. Precision was evaluated as the standard deviation of five repeated measurements of a 200 μm displacement along each axis. Both accuracy and precision were best along the longitudinal axis, with a prediction interval of ±47 μm in the human model and ±45 μm in the canine model and a standard deviation of 30 μm in the human model and 40 μm in the canine model. The use of only the prosthetic head as a landmark (as opposed to three markers placed on the femoral stem) led to a 3‐fold larger prediction interval in the human model and a 2‐fold greater prediction interval in the canine model. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. more...

A significant health care dilemma for older individuals living in rural areas is that at a time in life when there is, predictably, a greater need for medical services, the ability to access those limited services is markedly reduced. Telepsychiatry presents an innovative and cost‐effective strategy for the provision of improved local access to quality mental health services for the underserved rural elderly. Telepsychiatry has demonstrated the potential to improve access to mental health services, provide those services in an affordable and cost‐effective manner and deliver those services at a quality nearly equal to traditional face‐to‐face services. Advances in telepsychiatry technology allow a core group of skilled mental health providers in a central location to provide timely local access to quality services for the rural elderly over a broad geographic area. more...

In osteoarthritis, one postulate is that changes in the mechanical properties of the subchondral bone layer result in cartilage damage. The goal of this study was to examine changes in subchondral trabecular bone properties at the calcified tissue level in the early stages of cartilage damage. Finite element models were constructed from microCT scans of trabecular bone from the proximal tibia of donors with mild cartilage damage and from normal donors. In the donors with cartilage damage, macroscopic damage was present only in the medial compartment. The effective tissue elastic moduli were determined using a combination of finite element models and mechanical testing. The bone tissue modulus was reduced by 60% in the medial condyle of the cases with cartilage damage compared to the control specimens. Neither the presence of cartilage damage nor the anatomic site (medial vs. lateral) affected the elastic modulus at the apparent level. The volume fraction of trabecular bone was higher in the medial compartment compared to the lateral compartment of tibiae with cartilage damage (but not the controls), suggesting that mechanical properties were preserved in part at the apparent level by an increase in the bone volume fraction. It seems likely that the normal equilibrium between cartilage properties, bone tissue properties and bone volume fraction is disrupted early in the development of osteoarthritis. © 2001 Orthopaedic Research Society. Punlished by Elsevier Science Ltd. All rights reserved. more...

Radical changes in crop production have occurred in the southeastern USA in recent years. Peanut (Arachis hypogaeaL.) and cotton (Gossypium hirsutumL.) are now planted in direct rotation, and conservation tillage is commonly used for both crops. Comprehensive data is lacking on crop and pest management recommendations in those systems, so a long‐term study was conducted in Tifton, GA on the effects of tillage systems on crop and pest management in a peanut–cotton rotation. Systems evaluated were conventional, reduced, and minimum tillage. Plots in conventional tillage systems were harrowed, deep‐turned, and planted each year. In reduced tillage systems, plots were harrowed in the fall and planted to rye (Secale cerealeL.), and crops were planted into killed rye. In minimum tillage systems, plots were neither tilled nor planted to rye and remained nontilled during the winter, and crops were planted directly into the previous crop stubble. Weed control was based on species present and tillage system. Peanut was either treated with flutolanil [3′‐isopropoxy‐2‐(trifluoromethyl) benzanilide] for soil‐borne disease control or not treated (control). Yields were sustained for 5 yr with no difference in peanut or cotton yields among tillage systems. Flutolanil controlled soil‐borne diseases and increased peanut yields, working equally well in all three tillage systems. Weed densities and species composition changed, causing more intensive and costly weed control in reduced and minimum tillage systems than in conventional tillage systems. Spotted wilt (tomato spotted wilt tospovirus) incidence was 42% lower in reduced and minimum tillage systems than in conventional tillage systems and is now part of the recommended strategy to manage the disease. more...

High‐intensity storms that occur shortly after chemical application have the greatest potential to cause chemical runoff. We examined how effectively current chemical transport models GLEAMS, Opus, PRZM2β, and PRZM3 could predict water runoff and runoff losses of atrazine [6‐chloro‐N‐ethyl‐N′‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] under such conditions, as compared with observations from a controlled field runoff experiment. The experiment was conducted for 2 yr using simulated rainfall on two 14.6‐ by 42.7‐m plots within a corn (Zea maysL.) field on Tifton loamy sand (fine‐loamy, kaolinitic, thermic Plinthic Kandiudults) under conventional tillage practices. For each plot‐year, atrazine was applied as surface spray immediately after planting and followed by a 50‐mm, 2‐h simulated rainfall 24 h later. A similar preapplication rainfall and four subsequent rainfalls during the growing season were also applied. Observed water runoff averaged 20% of the applied rainfall. Less runoff occurred from freshly tilled soil or under full canopy cover; more runoff occurred when nearly bare soil had crusted. Observed total seasonal atrazine runoff averaged 2.7% of that applied, with the first posttreatment event runoff averaging 89% of the total. GLEAMS, Opus, PRZM2β and PRZM3 adequately predicted water runoff amounts, with normalized root mean square errors of 29, 29, 31, and 31%, respectively. GLEAMS and PRZM3 predicted atrazine concentrations in runoff within a factor of two of observed concentrations. PRZM2β overpredicted atrazine concentrations. Opus adequately predicted atrazine concentrations in runoff when it was run with an equilibrium adsorption submodel, but significantly underestimated atrazine concentrations when it was run with a kinetic sorption submodel. more...

Articles on chemigation with fungicides targeting foliage have been reviewed. They included 23 fungicides tested on 10 crops. Many studies compared chemigation to a check treatment, while others also included conventional methods. Chlorothalonil, followed by mancozeb, fentin hydroxide and captafol were the most studied fungicides, while peanut (Arachis hypogaea), potato (Solanum tuberosum), tomato (Lycopersicon esculentum ), and dry beans (Phaseolus vulgaris) were the most studied crops. Center pivot, followed by solid set, were the irrigation systems most frequently used. The minimum volume of water applied by some center pivots (25 000 litre ha⁻¹ ) is 25 times the maximum volume of water used by conventional ground sprayers. The reduction of fungicide residue on foliage caused by the very large volume of water used by chemigation might be offset by the following factors: (1) fungicide application at the time of maximum leaf wetness when fungi are most active, (2) complete coverage of plants, (3) reducing greatly the inoculum on plant and soil surface, (4) better control of some soil pathogens, and (5) more uniform distribution of fungicides by center pivot. Furthermore, chemigation avoids mechanical damage and soil compaction. Additionally, some systemic fungicides seem to be absorbed rapidly by the leaves, by root uptake from the soil, or by both. In general, all fungicides applied through irrigation water can lessen disease severity. However, when compared to conventional methods, chemigation with fungicides can be less, equally or more effective depending on crop, pathogen, disease severity, fungicide and volume of water. For Cercosporidium personatum control on peanuts, application of protectant fungicides through irrigation water is less effective than conventional methods, but the results with some systemic fungicides mixed with non-emulsified oil and applied through a relatively low volume of water (2.5 mm) are encouraging. Important diseases of potato and tomato can be controlled nearly as well by chemigation as by conventional methods without impairing yield. The main advantage of chemigation for these crops is avoiding a large number of tractor trips through the field and reduced costs of fungicide application. Chemigation has also been shown to be a good option for control of white mold [ Sclerotinia sclerotiorum] on dry beans. © 1999 Society of Chemical Industry more...

A new, in vitroultrasound-based method to measure the thickness of acetabular polyethylene components was developed and applied to 26 uncomplicated autopsy-retrieved components and 40 unused components. The average age at total hip arthroplasty was 62 years and the average time in service of the retrieved components was 49 months. The clinical notes indicated that each of the arthroplasties was functioning well at the time of the patients death. Thickness distributions in the retrieved components had two distinct patterns. Eighteen of the retrieved components (69%) had their thinnest areas self-contained and located near the polar point. In the other 8 retrieved components (31%) the areas of minimum thickness were adjacent to the rim. Thickness distribution in the unused cups was predominately concentric with the thinnest area located near the polar point (85% of the cups). Detection limits for dimensional change were established based on the variability found in the unused liners. Fifteen of the 26 retrieved components (58%) had areas of reduced thickness which exceeded the detection limits; the average thickness reduction rate for these components was 0.076 mm per year. The other 11 retrieved components (42%) lacked such areas. The 15 cups with areas of reduced thickness had a longer time in service (63 ± 18 months) than the 11 cups without areas of reduced thickness (32 ± 25 months) (p= 0.003), but no other clinical factor (age, gender, Harris hip score, size and inclination of the cup, type of femoral fixation) was associated with these 15 cups. Cylindrical models to estimate volumetric change tended to underestimate the actual changes, suggesting that the actual particulate burden may be greater than previously appreciated. more...