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Biomedical subjects

Lynne C Jones

Publications and source records attributed to Lynne C Jones.

17 recordsLinked to original sources
PubMed2006

Nontraumatic osteonecrosis of the femoral head: ten years later.

The etiology of osteonecrosis of the hip may have a genetic basis. The interaction between certain risk factors and a genetic predisposition may determine whether this disease will develop in a particular individual. The rationale for use of joint-sparing procedures in the treatment of this disease is based on radiographic measurements and findings with other imaging modalities. Early diagnosis and intervention prior to collapse of the femoral head is key to a successful outcome of joint-preserving procedures. The results of joint-preserving procedures are less satisfactory than the results of total hip arthroplasty for femoral heads that have already collapsed. New pharmacological measures as well as the use of growth and differentiation factors for the prevention and treatment of this disease may eventually alter our treatment approach, but it is necessary to await results of clinical research with long-term follow-up of these patients.

Arthroplasty↗
PubMed2006

Systematic analysis of classification systems for osteonecrosis of the femoral head.

BACKGROUND: Multiple classification systems for osteonecrosis of the hip have been developed to assist physicians in the diagnosis and treatment of this potentially debilitating disorder. The purpose of this analysis was to delineate the classification systems utilized in reports published since 1985 and, through a comparison of the most commonly used systems, to identify consistent factors that would allow for cross-publication comparisons to be made. METHODS: We performed a PubMed search for reports of outcome studies concerning treatment methods for osteonecrosis of the hip. All studies of reported outcomes with greater than ten patients were included in the analysis. Various classification systems were tabulated to determine usage frequencies. The four most commonly used systems were then analyzed to determine common factors used for classification. RESULTS: One hundred and fifty-seven studies were available for analysis. Sixteen major classification systems that made use of more than one radiographic factor were identified, and nine of these systems had one to five modifications reported throughout the literature. Additionally, eleven other systems made use of single factors obtained from either magnetic resonance imaging or anatomic data. The review revealed that four classification systems accounted for greater than 85.4% of the reported studies. Parameters for these four systems were stratified to allow for uniformity of patient or study evaluation. CONCLUSIONS: This analysis of the reported classification systems for osteonecrosis of the femoral head revealed several similarities between the most commonly used systems. An analysis of patients can be made with any of the four major systems if specific data are collected according to various magnetic resonance imaging and radiographic findings. This approach will allow for easier comparison of studies across different centers. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Classification↗
PubMed2006

Survivorship of femoral revision hip arthroplasty in patients with osteonecrosis.

BACKGROUND: Recent studies have indicated that the rate of successful long-term outcome after primary total hip arthroplasty for patients with osteonecrosis may be improved with the use of later-generation porous-coated prostheses (biologic ingrowth fixation) and cement techniques (cement fixation). Less is known about the long-term outcome after revision arthroplasty in the same patient population. The purpose of this study was to characterize the clinical and radiographic outcomes of revision total hip arthroplasty in patients with osteonecrosis. METHODS: We evaluated thirty-four osteonecrotic hips in thirty patients who had undergone revision of a femoral component of a prior total hip arthroplasty. There were nineteen men (twenty-two hips) and eleven women (twelve hips) with a mean age of forty-six years. Thirty one of thirty-four hips were implanted without cement. The cementless prostheses were of different stem lengths, but thirty of thirty-one were proximally porous coated. The mean duration of follow-up was 8.2 years. Prerevision radiographs were used to determine the degree of femoral bone loss according to the classification system of Della Valle and Paprosky. The need for revision was analyzed for correlation to known risk factors for osteonecrosis, age and gender of the patient, and degree of prerevision femoral deficiency. A clinical and radiographic evaluation of outcome was performed. RESULTS: This was the first revision for twenty-seven hips, the second for five hips, and the third for two hips. Preoperatively, the defects included four Type I, nine Type II, fifteen Type IIIA, two Type IIIB, one Type IV, and three unknown. The femoral component was rerevised in twelve of the thirty-four hips. One of the failures was the only fully porous-coated stem that was implanted. One of the three cemented implants failed, as compared with eleven of the thirty-one noncemented implants. Survival rates were 90.9% at five years, 54.8% at ten years, 54.8% at fifteen years, and 27.4% at twenty years. With the small sample size, no relationship could be identified with regard to frequency of re-revision and defects, associated risk factors, patient age, or gender. CONCLUSIONS: There was a high failure rate of revised, uncemented, proximally coated femoral components in patients with osteonecrosis of the femoral head at the time of the intermediate-term follow-up. The cause of failure could not be correlated with patient age, gender, risk factors for osteonecrosis, or femoral bone stock. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Adult↗
PubMed2006

Macrophages and fibroblasts respond differently to PMMA particles and mechanical strain.

A primary factor limiting the long-term outcome of total joint arthroplasty is the aseptic loosening of prosthetic components. The bone-host interface of an unstable implant is associated with large quantities of wear debris as well as an altered mechanical environment. In vitro cellular studies on the effects of particulate biomaterials have been conducted under static conditions. The principal objective of this study was to test the hypothesis that the application of cyclic tensile strain to cultured macrophages and fibroblasts alters the response of these cells to particulate polymethylmethacrylate. P388D1 macrophages and three human synovial fibroblast cells were exposed to particulate PMMA (0, 0.4, 4.0, and 40.0 mg/well) (n = 3) and tested under static or dynamic [cyclic tensile strain (0.5 Hz, 0.2 strain)] conditions. Cellular proliferation was determined by autoradiography following 3H-thymidine incorporation. IL-1beta, TNF-alpha, and IL-6 were identified using immunocytochemistry. Exposure of macrophages to particulate PMMA and/or cyclic tensile strain resulted in a decrease in DNA synthesis. Neither treatment altered the proliferative capacity of fibroblasts. Macrophages and fibroblasts stained positively for IL-1beta, TNF-alpha, and IL-6 under all of the experimental conditions tested. Our study provides evidence that macrophages, but not fibroblasts, exhibit decreased proliferative capacity when exposed to particulate PMMA and mechanical stimuli.

Biocompatible Materials↗
PubMed2006

The response of osteoblast-like cells to dexamethasone and cyclic loading.

The aim of this study was to investigate whether cyclic loading can alter the response of osteoblasts to dexamethasone. Proliferation of osteoblast-like cells (MG-63) was assessed by determining uptake of 3H-thymidine. Three doses of dexamethasone were tested: 0.001 nM, .001 nM, or 0.1 nM. Exposure to increasing levels of dexamethasone resulted in decreased proliferation of osteoblast-like cells. Although there was a slight decrease in proliferation seen in the controls (no dexamethasone) with cyclic loading, cyclic loading did not affect the response of osteoblast-like cells to dexamethasone under these test conditions. Varying loading conditions and the potential effect on metabolic and synthetic activity of the osteoblast-like cells need further study.

Cell Line↗
PubMed2004

Total knee arthroplasty in obese patients: a comparison with a matched control group.

Thirty knees in 27 obese patients were matched to 30 knees in 27 nonobese patients, with both cohorts followed for a mean of approximately 15 years. Nine of 30 obese knees were revised, whereas 3 of 30 nonobese knees were revised, with Knee Society objective scores being higher in the nonobese group. There were more polyethylene insert revisions in the nonobese group, which may have been accounted for by a trend of higher activity levels in this group. The authors concluded that at long-term follow-up, although not statistically significant, there was a trend for obesity to influence the rate of aseptic loosening. This may occur because of increasing stress at the bone-prosthesis interface, whereas increased activity levels in the nonobese patients may adversely affect the longevity of the polyethylene insert.

Adult↗
PubMed2004

Risk factors for pulmonary emboli after total hip or knee arthroplasty.

Because it is difficult to predict which patients may sustain a pulmonary embolism after total hip or knee arthroplasty, we assessed multiple thrombophilic and hypofibrinolytic parameters to identify risk factors. Twenty-nine patients who survived a known pulmonary embolism after total knee or total hip arthroplasty were matched by age, gender, race, arthritic diagnosis, procedure, and surgery date with 29 patient-controls who had a total hip or knee arthroplasty but who did not have a symptomatic known pulmonary embolism or deep vein thrombosis. Twenty-one serologic measures and five genes associated with thrombophilia, hypofibrinolysis, or both were assessed without knowledge of group assignment. All patients with pulmonary embolism had at least one abnormality of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol versus 13 of 27 (48%) control patients. Forty-seven percent of patients who experienced pulmonary embolism had at least two abnormalities of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol, versus 7% of control patients. Preoperatively, to identify patients at high risk of pulmonary embolism, plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, and cholesterol levels were most predictive. Using at least one abnormality of these four measures as a screening test to detect risk of pulmonary embolism, the test is sensitive (100%), and the predictive value of a negative test is high (100%). After additional prospective study, this may allow identification of patients at low risk (the majority of patients) in whom anticoagulation may not be required and a small group of patients at high risk for pulmonary embolism in whom prophylactic anticoagulation should be provided.

Age Distribution↗
PubMed2004

Osteonecrosis: etiology, diagnosis, and treatment.

PURPOSE OF REVIEW: This review provides an update of the recent progress in etiology, pathogenesis, diagnosis, and treatment of osteonecrosis. RECENT FINDINGS: Concerning pathogenesis, there is evidence that there is a genetic predilection for those who are exposed to the two leading etiologic associations for osteonecrosis: corticosteroids and alcohol. Studies concerning the treatment of osteonecrosis indicate that most preservative (ie, joint-sparing) procedures available today have better results in the precollapse stages of the disease and in smaller lesions. Therefore, researchers continue to develop and modify diagnostic techniques, particularly relating to MRI, for the identification and quantification of osteonecrotic lesions. Advances concerning bone grafting and arthroplasty procedures have resulted in improved clinical outcomes for this patient population. The future treatment of osteonecrosis may involve genetic or cell-based therapies. SUMMARY: Although progress has been made, considerably more research is needed before we fully understand this disease. Hopefully, such research will lead to effective measures for saving the femoral head or, better yet, preventing osteonecrosis.

Humans↗
PubMed2004

The outcome of total knee arthroplasty in obese patients.

BACKGROUND: Evidence linking increased body weight to osteoarthritis of the knee and the high prevalence of obesity underscore the importance of defining the outcome of total knee arthroplasty in obese patients. The purpose of this study was to compare the clinical and radiographic results of total knee arthroplasties performed in obese patients with those of total knee arthroplasties performed in nonobese patients. METHODS: Clinical and radiographic data on seventy-eight total knee arthroplasties in sixty-eight obese patients were compared with data on a matched group of nonobese patients. The analysis was also performed after stratification of the obese group for the degree of obesity. All patients had the same prosthesis. The clinical data that were analyzed included the Knee Society objective and functional scores, patellofemoral symptoms, activity level, and complications. RESULTS: The percentage of knees with a Knee Society score of > or =80 points at an average of eighty months was 88% in the obese group, which was significantly lower than the 99% rate in the nonobese group at the same time. The morbidly obese subgroup had a significantly higher revision rate than did the nonobese group (p = 0.02). CONCLUSIONS: The results of the present study suggest that any degree of obesity, defined as a body mass index of > or =30, has a negative effect on the outcome of total knee replacement.

Adult↗
PubMed2004

Asymptomatic osteonecrosis: should it be treated?

Currently, there is no consensus regarding the treatment of precollapse osteonecrosis, particularly for asymptomatic osteonecrosis. With approximately 10,000 to 20,000 new cases of osteonecrosis a year, no single surgeon or center has the kind of experience that is able to address the most important questions concerning this disease. The literature strongly documents that symptoms of osteonecrosis will progress. Although the literature also supports the progression of asymptomatic osteonecrosis to symptomatic osteonecrosis on to collapse, that support is less convincing. Progression is proportional to lesion size, with small lesions (< 15% of femoral head involvement by volume) unlikely to progress. Although the results of core decompression have been somewhat controversial, the weight of the literature supports both the efficacy and safety of the procedure. The decision to treat osteonecrosis with core decompression is primarily based upon lesion size and stage of disease and does not necessarily depend on whether the patient is symptomatic. As large lesions (> 30% of the femoral head) are less likely to be successfully treated by core decompression and small lesions (< 15% of the femoral head) are less likely to progress, asymptomatic lesions within these ranges can be observed. The literature supports the position that moderately sized lesions (15-30% of the femoral head) should be treated by core decompression (with or without bone grafting).

Age Distribution↗
PubMed2003

Glucosamine and chondroitin sulfate are effective in the management of osteoarthritis.

The use of glucosamine and chondroitin sulfate for the symptomatic treatment of osteoarthritis has been a subject of controversy for several reasons. First, the medical community in general took offense at the title of Theodosakis' book, The Arthritis Cure. Second, the medical community is becoming divided into "traditional" and "alternative" camps with deep skepticism between them. Third, the whole nutraceutical industry is essentially unregulated, with manufacturers making outrageous claims on products that have never been tested at all, are often of poor quality, and occasionally lacking in any active ingredient. However, for the nutriceuticals evaluated here, there is abundant in vitro, in vivo, animal clinical, and human clinical evidence of both their efficacy and safety. They deserve a prominent place in the armamentarium of nonsurgical treatment of osteoarthritis.

Animals↗
PubMed2003

Procoagulants and osteonecrosis.

OBJECTIVE: To study the relationship between hypofibrinolysis, thrombophilia, and osteonecrosis. We evaluated the frequency of abnormal concentrations of 9 coagulation factors in patients diagnosed with osteonecrosis. METHODS: Blood samples were drawn from 45 patients diagnosed with osteonecrosis. Etiologic associations included systemic lupus erythematosus (n = 9), inflammatory bowel disease (n = 1), corticosteroid therapy (n = 20), or history of heavy alcohol (n = 4) or tobacco (n = 3) use. No associated risk factors were identified in 5 patients; these individuals were labeled "idiopathic." The patient cohort was matched to a similarly studied cohort of 40 healthy individuals without documented osteonecrosis. The following factors were analyzed: plasminogen activator inhibitor (PAI-Fx), stimulated tissue plasminogen activator, lipoprotein (a), resistance to activated protein C, anticardiolipin antibodies (aCL IgG, IgM), protein C, protein S (free), and homocysteine. RESULTS: Thirty-seven of the 45 patients (82.2%) with osteonecrosis were found to have at least one coagulopathy, versus 30% of controls (p < 0.0001). Twenty-one patients (46.7%) were identified with 2 or more abnormal test results versus 2.5% of controls (p < 0.0001). Patients were more likely than controls to have high levels of the hypofibrinolytic plasminogen activator inhibitor activity (42% vs 3%; p < 0.0001), and high anticardiolipin antibody IgG (34% vs 10%; p = 0.008). At least one coagulation factor abnormality was detected in all 5 idiopathic patients; elevated aCL IgG and PAI-Fx were evident in 4 patients. CONCLUSION: This study revealed a high incidence of thrombophilic and hypofibrinolytic coagulation abnormalities in patients with osteonecrosis. These findings have major implications for the diagnosis as well as the treatment of this disease. Since some of these abnormalities may be the result of autosomal dominant disorders, it may be possible to detect individuals at risk for development of this disease.

Adult↗
PubMed2002

Is coding of diagnoses, comorbidities, and complications in total knee arthroplasty accurate?

Coding of diagnoses, comorbidities, and complications is important for health care delivery, not only for appropriate hospital and physician reimbursement, but also for a correct assessment of complication rates. The purpose of this study was to determine the agreement of coding of diagnoses, comorbidities, and complications for total knee arthroplasty between 2 groups of coders. Between January 1, 1997, and November 18, 1997, 100 consecutive primary total knee arthroplasties were done by 2 orthopaedic surgeons. Diagnoses, comorbidities, and complications were coded by professional hospital coders according to the Healthcare Finance Administration guidelines, then recoded by a second team with orthopaedic experience. Although the hospital coders matched diagnoses with the orthopaedic team 96.5% of the time, they determined a complication rate of 1.4 per patient and a comorbidity rate of 2.9 per patient, whereas the orthopaedic team coded for 0.7 complications per patient and 3.7 comorbidities. Based on these results, there should be interaction and communication between hospital coders and health care professionals to check that coding is accurate and reproducible.

Adult↗
PubMed2002

Varus and valgus flexion laxity of total knee alignment methods in loaded cadaveric knees.

Both total knee alignment methods, the anatomic and classic, seek to achieve stability in flexion and extension. However, posterior femoral condyle referencing (anatomic alignment) combined with perpendicular tibial resection (classic alignment) results in a 3 degree relative internal rotation of the femoral component with lateral joint opening. The current cadaver study investigated the influence of total knee alignment methods and femoral component malrotation (3 degrees and 6 degrees internal and external malrotation) on femorotibial laxity. Varus and valgus excursion tests were done at 0 degrees, 30 degrees, 60 degrees, and 90 degrees knee flexion under vertical loading conditions of 150 N. None of the alignments produced increased laxity in extension. The largest laxity was found on the varus test at 60 degrees flexion with the femoral component at 6 degrees internal rotation. A 3 degree internal rotation of the femoral component showed increased varus laxity only for the combined alignment method. This finding shows that the femoral component position of the combined alignment method is a 3 degree relative internal malrotation and that an additional internal malrotation may compromise varus stability. Posterior femoral condyle referencing did not provide proper femoral component rotation. A ligament tensor may be helpful in determining femoral component rotation after soft tissue release in extension is performed.

Arthroplasty, Replacement, Knee↗
PubMed2002

The fate of revised uncemented acetabular components in patients with rheumatoid arthritis.

The results of patients with rheumatoid arthritis who had revision hip arthroplasty have been studied infrequently. The purpose of this study was to review the authors' clinical and radiographic experiences and outcomes with revision hip arthroplasty. Revision total hip arthroplasties were done on 28 patients (30 hips). All hips had morselized bone grafting and four hips had bulk allografts for segmental defects. The mean age of the patients at the time of surgery was 50 years (range, 20-74 years). Patients were followed up for 4 to 15 years (mean, 7 years). At the latest followup, 14 hips (13 patients) of the 30 hips (47%) had good and excellent Harris hip score ratings. Mechanical failures included six hips (five patients) that had revision arthroplasty and two hips (two patients) that had resection arthroplasty. Six other hips (five patients) had poor Harris hip score ratings. The Kaplan-Meier survivorship curve for failure of the acetabular component revealed an 89% chance of survivorship curve for failure of the acetabular component revealed an 89% chance of survival at 60 months and a 44% chance of survival at 108 months. Based on the results of this study, revision hip arthroplasty for acetabular loosening with a cementless acetabular prosthesis has a low rate of success in patients with rheumatoid arthritis.

Adult↗
PubMed2002

Coding of diagnoses, comorbidities, and complications of total hip arthroplasty.

International Classification of Diseases coding of patient charts is used by hospitals to allow for billing of patients. Coding information also is used for assessing physician effectiveness. The purpose of the current study was to examine hospital coding for patients having total hip arthroplasty. One hundred consecutive primary total hip replacements were done at one medical center by two orthopaedic surgeons. Patient charts were coded by hospital coders according to the Health Care Finance Administration guidelines. Subsequently, an orthopaedist-based team did a secondary review of these charts and the two sets of codes were compared. The diagnostic codes were similar between the two groups for 87% (174 of 200 codes) of the cases. Comorbidities generally were undercoded by the hospital coders who reported 2.9 comorbidities per patient, whereas the secondary review reported 3.7 comorbidities per patient. The hospital coders found a complication rate of 1.2 per patient, whereas the secondary review revealed a rate of 0.4 per patient. Based on the results of the current study, the authors conclude that it is important to ensure three issues regarding the standard of coding and quality control: (1) the qualifications of the coders; (2) an interaction between coders and healthcare professionals to check that coding is accurate and reproducible; and (3) communication among various health professionals (including the primary surgeon) and coders to determine what actually are appropriate diagnoses, comorbidities, and complications.

Arthroplasty, Replacement, Hip↗