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Biomedical subjects

Thomas E Brown

Publications and source records attributed to Thomas E Brown.

15 recordsLinked to original sources
PubMed2006

Acute sciatic neuritis following total hip arthroplasty: a case report.

Nerve injuries after total hip arthroplasty are relatively uncommon, but a higher prevalence has been reported in revision arthroplasties, in women and in patients with dysplastic hips. We report a case of a patient who had a painful neuritis of the sciatic nerve after primary arthroplasty, without any objective evidence of motor or sensory deficit and had complete relief of pain after the limb lengths were matched to the contra-lateral side after revision arthroplasty.

Acute Disease↗
PubMed2006

Primary total knee arthroplasty with condylar allograft and MCL reconstruction for a comminuted medial condyle fracture in an arthritic knee--a case report.

Fractures of the distal femur in the elderly are usually due to low energy ground level fall onto a flexed knee. Pre-existing osteoarthritis and juxta-articular osteopenia in this age group result in high levels of comminution and articular damage at the time of injury, which challenges the management and treatment outcome. Preservation of knee function and early weight bearing should be the objectives of management in the geriatric population. We present in this case report of an elderly patient with comminuted medial condyle fracture with arthritic changes who had primary total knee arthroplasty utilizing condylar allograft and MCL reconstruction as an alternative to internal fixation.

Accidental Falls↗
PubMed2006

Patellofemoral instability after total knee arthroplasty.

UNLABELLED: Despite advances in surgical technique and implant design, complications involving the extensor mechanism and patellofemoral joint after total knee arthroplasty (TKA) continue to be the most common cause of pain and the most commonly cited reason for revision TKA surgery. A thorough understanding of the etiologies of patellofemoral instability, careful preoperative planning, and meticulous surgical techniques will optimize clinical outcome. Evaluation of patellofemoral stability should begin in the operating room. Postoperatively, thorough history, physical examination, and dedicated radiographic studies should be obtained. Computed tomography scan is the most accurate and reliable way to assess component positioning. Treatment of patellofemoral instability is directed by its etiology. Revision of one or both components is indicated if malpositioning is present. If the components are determined to be in satisfactory positions, soft tissue procedures can be pursued. Future advancements in prosthetic design and the routine use of computer-assisted navigation systems will minimize patellofemoral instability. LEVEL OF EVIDENCE: Therapeutic study, Level V (expert opinion). See the Guidelines for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Extensor mechanism disruption after total knee arthroplasty.

UNLABELLED: Extensor mechanism disruption after total knee arthroplasty is a challenging complication for orthopaedic surgeons. The treatment options for repair include observation, direct primary repair, direct primary repair with synthetic ligament or autogenous tissue augmentation, or reconstruction with allograft tissue. A computerized systemic review and literature search was performed to identify the relevant literature on extensor mechanism disruptions associated with total knee arthroplasty. A comprehensive review of the literature and description of relevant treatment options and outcomes were performed using the information gained with the literature review. A multi-center prospective study on a consecutive series of patients recruited from the North American Knee Arthroplasty Revision (NAKAR) study was performed and data collected pre-operatively, intra-operatively, and post-operatively on patients that had a failed total knee arthroplasty using validated health related quality of life measures was analyzed. Six out of 290 patients in the study had extensor mechanism disruption and this group of patients had overall worse functional outcomes. The results of the study have solidified our knowledge that patients with extensor mechanism disruptions have worse functional outcomes and will need intensive management and rehabilitation. LEVEL OF EVIDENCE: Economic and decision analyses, level III (systematic review of level III studies). See Guide for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2006

Increased surgical volume is associated with lower THA dislocation rates.

The presumed correlation between an increasing volume of health care procedures and an improvement in outcomes is sometimes referred to as the practice-makes-perfect effect. Growing interest in outcomes-based research has led to numerous papers examining this relationship for various surgical procedures, including total hip arthroplasty. The results of these studies have important implications for consumers, providers, and healthcare financers. Accordingly, we review the literature to date examining surgeon and hospital volume effects on hip arthroplasty outcomes, with a specific focus on the effects of volume on dislocation. A systemic review of the literature demonstrates a substantial positive association between surgical volumes and improvement in most THA outcomes, including dislocation; that is, increasing surgical volume is associated with lower dislocation rates. This correlation appears to be stronger and is more clearly established for surgeon volumes than it is for hospital volumes.

Arthroplasty, Replacement, Hip↗
PubMed2006

Does surgical approach affect total hip arthroplasty dislocation rates?

Dislocation is a common complication of total hip arthroplasty, but exact effect of surgical approach on dislocation rates remains unclear. Because little randomized prospective data exist in this context, we performed a meta-analysis comparing dislocation rates using the posterior approach with and without soft tissue repair. A systematic literature review resulted in five studies which directly compared the posterior approach with and without soft tissue repair. The dislocation rates with and without repair were 0.49% and 4.46%, respectively. The relative risk for dislocation was determined using a fixed effects model with chi square test for interstudy heterogeneity. The posterior approach without soft tissue repair was found to have an 8.21 times greater relative risk of dislocation than with soft tissue repair (95% confidence interval, 4.05-16.67). A separate systematic review of 11 studies revealed comparable dislocation rates associated with the anterolateral, direct lateral, and posterior approaches with soft tissue repair (0.70%, 0.43%, and 1.01%, respectively). These data demonstrate that adequate soft tissue repair greatly reduces the relative risk of dislocation using the posterior approach, and that the dislocation rates for the three most prevalent approaches are similar. Further prospective randomized trials examining dislocation rates and other clinical parameters are needed.

Age Distribution↗
PubMed2005

A novel total knee arthroplasty infection model in rabbits.

Infection of biomaterial implants is an expensive and devastating complication of orthopaedic surgery historically ranging from less than 1% in primary total knee arthroplasty (TKA) to 10% in revision TKA. An in vivo animal model was developed to test the efficacy of innovative therapies for the prevention of biomaterial centered infections caused by methicillin-resistant Staphylococcus aureus bacteria (MRSA). Twenty-two New Zealand White rabbits were used in this study. After proper anesthesia, a stainless-steel screw with a high molecular weight polyethylene (UHMWPE) washer was cemented in a defect created in the intra-articular, non-articulating portion of the lateral femoral condyle of each knee. After closure of the joint capsule, each knee was inoculated with 0, 10(2), 10(3), or 10(4) colony forming units (CFU) of MRSA. Animals were sacrificed after 7 days at which time joint aspirate, tissues and biomaterial samples were examined for evidence of infection. A total of 42 knees were used for analysis. When saline was injected into the knee, 0/10 of the knees demonstrated evidence of biomaterial centered infection (with the contralateral knee receiving 10(4)CFU MRSA). Four of 10 knees developed a biomaterial centered infection when 10(2)CFU MRSA was introduced. Seven out of 10 knees developed a biomaterial centered infection when either 10(3) or 10(4)CFU MRSA was injected. No evidence of septicemia (positive blood cultures) was found in any animal. This rabbit knee model utilizes commonly employed inexpensive orthopaedic implant materials in an in vivo milieu and provides an effective method for the evaluation of treatments for biomaterial centered infections.

Animals↗
PubMed2005

Attention-deficit/hyperactivity disorder among adolescents: a review of the diagnosis, treatment, and clinical implications.

Attention-deficit/hyperactivity disorder (ADHD) is the most common mental disorder in childhood, and primary care clinicians provide a major component of the care for children with ADHD. However, because of limited available evidence, the American Academy of Pediatrics guidelines did not include adolescents and young adults. Contrary to previous beliefs, it has become clear that, in most cases, ADHD does not resolve once children enter puberty. This article reviews the current evidence about the diagnosis and treatment of adolescents and young adults with ADHD and describes how the information informs practice. It describes some of the unique characteristics observed among adolescents, as well as how the core symptoms change with maturity. The diagnostic process is discussed, as well as approaches to the care of adolescents to improve adherences. Both psychosocial and pharmacologic interventions are reviewed, and there is a discussion of these patients' transition into young adulthood. The article also indicates that research is needed to identify the unique adolescent characteristics of ADHD and effective psychosocial and pharmacologic treatments.

Adolescent↗
PubMed2004

The porous-coated anatomic total hip prosthesis: 11- to 13-year results.

Of 137 consecutive primary porous-coated anatomic (PCA) arthroplasties performed, complete data was available on 107 hips in 93 patients at an average of 12.4 years (range, 11-13 years). The average Harris Hip Score improved from 44 to 85 at final follow-up, with 78% good or excellent result. Thirteen percent (14 of 107) of acetabular components and 4 porous ingrowth stems were deemed failures. Osteolytic lesions were seen in 7.5% (8 of 107) of acetabular components. Survivorship of the PCA prosthesis as a whole was 83% at 12.4 years. This first-generation femoral stem performed well, with only 4 failures, all of which occurred in patients with avascular necrosis in which unrecognized pathologic changes in the proximal femur may have inhibited bone ingrowth. The majority of the failures can be attributed to aseptic loosening of the acetabular component.

Adult↗
PubMed2004

Atomoxetine and stimulants in combination for treatment of attention deficit hyperactivity disorder: four case reports.

Atomoxetine and stimulants have both been demonstrated effective as single agents for treatment of attention deficit hyperactivity disorder in children, adolescents, and adults. However, attention deficit hyperactivity disorder symptoms in some patients do not respond adequately to single-agent treatment with these medications, each of which is presumed to impact dopaminergic and noradrenergic networks by alternative mechanisms in different ratios. Four cases are presented to illustrate how atomoxetine and stimulants can be utilized effectively in combination to extend duration of symptom relief without intolerable side effects or to alleviate a wider range of impairing symptoms than either agent alone. This combined pharmacotherapy appears effective for some patients who do not respond adequately to monotherapy, but because there is virtually no research to establish safety and effectiveness of such strategies, careful monitoring is needed.

Adolescent↗
PubMed2003

Assessment of short-term verbal memory impairments in adolescents and adults with ADHD.

The purpose of this study was to determine whether a brief measure of verbal memory can assess short-term verbal memory impairments relative to verbal abilities in adolescents and adults with Attention-Deficit/Hyperactivity Disorder (ADHD) and to ascertain whether significant differences between short-term verbal memory and verbal abilities are more common among persons with ADHD than in the general population. One hundred seventy-six adolescents and adults diagnosed with ADHD (DSM-IV criteria) were assessed with a measure of short-term verbal memory. The short-term verbal memory score of each subject was compared with the verbal abilities on two measures. Percentages of ADHD subjects with "significant discrepancy" between verbal IQ and short-term verbal memory were compared with the standardization sample for the verbal memory measure. A majority of adolescents and adults diagnosed with ADHD demonstrated significant discrepancy between performance on the short-term verbal memory measure and verbal IQ. The percentage of ADHD subjects with a significant discrepancy between these two measures greatly exceeded the percentage of persons in the general population showing such a discrepancy. This brief measure of short-term verbal memory may be a useful measure to include in a comprehensive assessment for ADHD symptoms in adolescents and adults. Replication in other groups of ADHD patients is needed to test the generalizability of the findings.

Adolescent↗
PubMed2002

The fate of stable femoral components retained during isolated acetabular revision: a six-to-twelve-year follow-up study.

BACKGROUND: The decision as to whether to revise a well-fixed femoral component in hips requiring isolated acetabular revision is challenging. The purpose of the present study was to determine the long-term results of, and the complications associated with, retention of a stable and well-fixed femoral component during isolated acetabular revision. METHODS: We retrospectively reviewed the clinical and radiographic results for thirty-one patients (thirty-two hips) who underwent isolated revision acetabuloplasty without removal of a well-fixed femoral component. The reason for acetabular revision was aseptic loosening in thirty-one hips and malposition in one hip. Of the thirty-two femoral components, twenty-one were cemented and eleven were cementless. The average duration of follow-up from the time of the index revision was 8.1 years (range, 6.4 to 12.5 years), and the average duration of total service of the femoral component was seventeen years (range, seven to twenty-five years) from time of the initial implantation. The average age of the patients at the time of the index revision was sixty-six years (range, twenty-nine to eighty-seven years). RESULTS: Thirty-one (97%) of the primary femoral components were judged to be stable and well fixed at the latest follow-up evaluation. One femoral component (3%) was revised because of aseptic loosening, eight years after the index acetabular revision and seventeen years after the initial total hip arthroplasty. Radiographic evaluation of the thirty-one femoral components that were not revised demonstrated no evidence of loosening or subsidence. There were no dislocations, nerve palsies, or intraoperative fractures associated with retention of the femoral component. Twenty-seven (84%) of the acetabular components were judged to be stable at the latest follow-up evaluation. CONCLUSION: In hips treated with isolated acetabular revision, a well-fixed femoral component can be retained successfully without adversely affecting the acetabular exposure; the placement, position, or stability of the acetabular component; or the ability to restore bone stock. The data from the present study support the decision to retain a well-fixed femoral component when the acetabular component needs to be revised.

Acetabulum↗
PubMedDate not supplied

Thigh pain after cementless total hip arthroplasty: evaluation and management.

Data from short- and long-term follow-up studies indicate that thigh pain is a significant complication after apparently successful cementless total hip arthroplasty. In most cases, reported symptoms are mild to moderate, resolve spontaneously or do not progress, and require little or no therapeutic intervention. However, persistent thigh pain may be a source of dissatisfaction or may present as severe, disabling pain. Possible causes include bone-prosthesis micromotion, excessive stress transfer to the femur, periosteal irritation, or a mismatch in Young's modulus of elasticity that increases the structural rigidity of the prosthetic stem relative to the femur. Thorough diagnostic evaluation of thigh pain is essential to rule out prosthetic infection or loosening, stress fracture, or spinal pathology as the primary source. Treatment options in the aseptic, well-fixed femoral component include medical management, revision of the femoral component, or cortical strut grafting at the tip of the implant.

Arthroplasty, Replacement, Hip↗