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Biomedical subjects

D M LaPorte

Publications and source records attributed to D M LaPorte.

11 recordsLinked to original sources

Human immunodeficiency virus testing for elective orthopedic procedures: results in a community-based hospital.

Between January 1, 1989 and July 31, 1995, voluntary preoperative screening tests for human immunodeficiency virus (HIV) infection, using an enzyme-linked immunosorbant assay, were completed on 2,727 patients who underwent elective orthopedic surgical procedures. There were 2,719 (99.7%) negative, 4 (0.15%) positive, and 3 (0.11%) false-positive results; 1 test was indeterminate (0.04%). All 4 positive patients were men with a mean age of 32 years (range: 26-43 years). Although the prevalence of positive tests is low in this setting, voluntary testing alerts the surgeon to higher risk patients, does not sacrifice patient care, and enables the incorporation of more extensive precautionary measures in the operating room to minimize occupational risks to the surgical team.

Adult↗

Deep wound infections after neuromuscular scoliosis surgery: a multicenter study of risk factors and treatment outcomes.

STUDY DESIGN: A retrospective case-control study evaluating risk factors for infection, causative organisms, and results of treatment in patients with cerebral palsy or myelomeningocele who underwent fusion for scoliosis was performed. OBJECTIVES: To identify risk factors for infection, and to characterize the infections in terms of infecting organisms and response to treatment. SUMMARY OF BACKGROUND DATA: No previous studies have analyzed risk factors or causative organisms, nor have they indicated results of treatment for infections in this group of patients. METHODS: After a 10-year retrospective review of 210 surgically treated patients, deep wound infections developed in 16 patients with myelomeningocele and 9 patients with cerebral palsy. These patients were studied extensively for possible risk factors, along with 50 uninfected patients matched for age, diagnosis, and year of surgery. Statistical testing was performed to identify risk factors. The courses of the infections were characterized in terms of organisms isolated and response to treatment. Treatment was performed in a stepwise fashion and classified in terms of the most successful step: debridement and closure, granulation over rods, or instrumentation removal. RESULTS: Of the 10 risk factors tested, 2 were found to be significant: degree of cognitive impairment and use of allograft. Findings showed that 52% of the infections were polymicrobial. Gram-negative organisms were isolated as commonly as gram-positive organisms. The most common organisms were coagulase-negative Staphylococcus, Enterobacter, Enterococcus, and Escherichia coli.- Debridement and closure were successful in 11 of 25 patients with deep wound infection. Of the 14 patients with infection not resolved by serial debridements and closure, 2 were managed successfully by allowing the wound to granulate over rods, and 7 required rod removal for persistent wound drainage. There were three symptomatic pseudarthroses. Infections resulting from gram-positive organisms were most often managed successfully with debridement and closure (P = 0.012). CONCLUSIONS: Patients with cerebral palsy or myelomeningocele who have severe cognitive impairment, and those who received allograft may be at increased risk for infection. Infections are more often polymicrobial and caused by gram-negative organisms than is typical for elective orthopedic procedures. This suggests an enteric source. Treatment with debridement and closure was not always successful. Patients in whom infection develops are then at increased risk for pseudarthrosis.

Adolescent↗

Atraumatic osteonecrosis of the adult elbow.

Osteonecrosis is a disease that leads to joint destruction and often involves large joints, such as the hips, knees, and shoulders. Nontraumatic osteonecrosis of the adult elbow, to the best of the authors' knowledge, has not been reported. Nine adult patients with atraumatic osteonecrosis of 11 elbows were identified. The mean age at presentation was 36 years (range, 26-63 years); five patients were women and four were men. Six elbows involved the capitellum, three involved the lateral epicondyles, one involved the trochlea and radial head, and one involved medial and lateral epicondylar disease. All patients were receiving corticosteroid therapy, and no relationship between the duration or the amount of corticosteroid use and the severity of the osteonecrosis was found. Seven patients with radiographic Stage I and Stage II disease responded well to nonoperative treatments consisting of activity modification, analgesics, and a brief period of immobilization. Nonoperative treatment failed in two patients with Stage III disease, and they had core decompressions for pain relief. One patient with late Stage III disease in both elbows underwent bilateral total elbow arthroplasties. In contrast to the pediatric population, osteonecrosis of the adult elbow potentially can lead to end stage arthritis. If the osteonecrosis is diagnosed early, nonoperative treatment may be effective in relieving pain, although the long-term results of these treatments remain unknown.

Adrenal Cortex Hormones↗

Infections associated with dental procedures in total hip arthroplasty.

Dental procedures may lead to a transient bacteraemia lasting for up to 30 minutes. Of the numerous cases of total hip arthroplasty (THA) reported which have been infected from haematogenous sources, dental procedures have been involved only infrequently. We reviewed the records of 2973 patients after THA. Of the late infections identified in 52 patients, three (6%) were strongly associated with a dental procedure. Infection was diagnosed by culture from the affected joint; Streptococcus viridans was identified in two cases and Peptostreptococcus in one. One patient had diabetes mellitus and another rheumatoid arthritis, both conditions predisposing to infection. The dental operations all lasted for more than 45 minutes and no patient received perioperative antibiotics. Infection of a THA after dental procedures is more common than has been previously suspected. Patients with systemic disease, or who are undergoing extensive procedures, should be considered for prophylactic antibiotic treatment.

Antibiotic Prophylaxis↗

Proximally porous-coated ingrowth prostheses: limits of use.

Callaghan has suggested that the most important factor in obtaining optimal results after total hip arthroplasty may be the ability to determine when to use cemented or cementless fixation. This article has presented the indications and relative contraindications for use of proximally porous-coated prostheses. Midterm results suggest that with appropriate patient selection, excellent clinical results can be achieved with currently available proximally porous-coated prostheses. Use of proximally coated prostheses is indicated for primary total hip arthroplasty in patients aged >70 years with good bone stock. Relative contraindications are based on interference with bone ingrowth or with the ability to achieve a congruent fit, both of which preclude establishment of rigid initial stability. These conditions include metabolic bone disease such as osteoporosis, osteomalacia, Gaucher's disease, sickle cell disorders, and Paget's disease; significant anatomical distortion, as seen in developmental dysplasia of the hip with anteversion, prior osteotomy, or intertrochanteric fracture; Dorr type C bone; and current treatment with radiation, chemotherapy, indomethacin, or diphosphonates. The same relative contraindications to use are applicable in revision situations. Further, proximally porous-coated prostheses should not be used for revision arthroplasty in the setting of massive bone loss, limited life expectancy, or inability to participate in protected weight bearing. These devices may be used successfully in revision arthroplasty when the hip has minimal or moderate bone loss, and occasionally in the setting of severe bone loss. As further information is revealed through the long-term (10-20 years) results of proximally coated prostheses, further refinements and knowledge of the indications and contraindications for the use of these prostheses will be revealed.

Arthroplasty, Replacement, Hip↗

Patellofemoral complications after total knee arthroplasty: a comparison of Modular Porous-Coated Anatomic with Duracon prostheses.

Clinical and radiographic analyses were used to compare results obtained in 45 patients who underwent a Modular Porous-Coated Anatomic total knee arthroplasty with results in a similar group of 45 patients who underwent a Duracon total knee arthroplasty. The surgeries were consecutively performed over an 8-month period, and follow-up evaluation averaged 63 months. The two patient groups were similar with regard to the following variables: age, sex, diagnosis, height, weight, and preoperative and postoperative activity levels. Whereas both Duracon and Modular total knee arthroplasty prostheses yielded similar results approximately 5 years after surgery, the data suggest that Duracon appears to minimize patellofemoral complications.

Adult↗

Pathologic features in steroid and nonsteroid associated osteonecrosis.

Multiple pathophysiologies for osteonecrosis have been postulated and various associated risk factors defined for this disease. However, the pathologic findings of the end stage disease are thought to be similar in all patients. To the author's knowledge, there are no data in the literature comparing the pathologic characteristics of osteonecrosis in a quantitative manner between groups of patients with different associated risk factors. The current study examined the pathologic features of core decompression specimens from the femoral head in a group of patients with osteonecrosis associated with corticosteroid therapy and compared them with specimens from patients with osteonecrosis with no history of corticosteroid therapy. The study group comprised 65 patients (96 hips); 45 patients (68 hips) in the corticosteroid group and 20 patients (28 hips) in the noncorticosteroid group. In the corticosteroid group, 65% of dead bone was identified histologically (44 of 68) as compared with 46% (13 of 28) in the noncorticosteroid group. Specimens staged according to the histologic grading system of Arlet and Durroux revealed the corticosteroid group had a higher incidence of late stage lesions than did the noncorticosteroid group. This was found even though the two groups had similar radiographic staging distribution. The hips in patients who used alcohol were comparable pathologically to the hips in patients who used corticosteroids. This study emphasizes that the histologic features of necrosis and repair are similar in corticosteroid and noncorticosteroid osteonecrosis. However, there were differences in the distribution of viable bone and pathologic stage of the lesions in the two groups, suggesting a more rapid evolution of changes in the corticosteroid group.

Adult↗

Osteonecrosis of the humeral head treated by core decompression.

Core decompression is one treatment used for symptomatic osteonecrosis of the humeral head. The purpose of this report was to examine the long term outcome of this procedure. Sixty-three shoulders in 43 patients who underwent a core decompression for humeral head osteonecrosis were followed up from 2 to 20 years (mean, 10 years). None of these patients had responded to nonoperative treatment before core decompression. Results of core decompression according to preoperative Ficat and Arlet stage revealed Stage I disease had 15 of 16 (94%) successful outcomes and Stage II had 15 of 17 (88%) successful outcomes. Stage III had 16 of 23 (70%) successful results and Stage IV had one of seven (14%) successful result. Core decompression of the shoulder is a safe procedure with few recognized complications and can be performed on an outpatient basis. The procedure has been successful for Stages I, II, and III osteonecrosis in terms of early relief of pain and increased function.

Activities of Daily Living↗

Multifocal osteonecrosis.

OBJECTIVE: To study demographic, clinical, and radiographic staging patterns in patients with multifocal osteonecrosis to facilitate earlier diagnosis and optimize treatment. METHODS: Multifocal osteonecrosis was defined as disease of 3 or more anatomic sites. Patients were characterized demographically, which included disease associations, corticosteroid and other agent usage, presenting joints, and symptomatology. Radiographically, patients were evaluated with plain radiographs and magnetic resonance imaging (MRI) scans of all joints to determine the presenting stage of the lesions. RESULTS: We found that 32 of 1056 (3%) osteonecrosis patients under our care had multifocal disease. Associated factors included systemic lupus erythematosus (13 patients), inflammatory bowel disease (5 patients), malignancy (4 patients), and renal transplantation (3 patients). Thirty of the 32 patients (94%) had a history of corticosteroid therapy, with the other 2 patients found to have a coagulopathy. All 32 patients had bilateral femoral head involvement and 30 of 32 had bilateral knee involvement, with the other 2 having only left knee lesions. Osteonecrosis was also seen in the shoulder (28 patients), ankle (8 patients), and 3 other sites. Overall, 201 sites were involved (6.3 per patient). The majority of joints presented in a pre-collapse stage (77%). Patients most commonly presented with hip or multiple joint symptoms (22 patients, 69%). In 8 patients, the knee was the sole presenting symptomatic joint and the ankle and shoulder were the sole presenting symptomatic joints in one patient each. CONCLUSION: In patients with a diagnosis of osteonecrosis and complaints in other joints, these other areas should be fully evaluated with plain radiographs and, if inconclusive, with MRI. In patients with osteonecrosis not involving the femoral head, the patient's hips should be radiographically evaluated regardless of whether the patient is symptomatic. Patients diagnosed with osteonecrosis of the knee, shoulder, or ankle should have other joints evaluated, as such patients have multifocal disease roughly 50% of the time.

Adrenal Cortex Hormones↗

Tennis after total hip arthroplasty.

The purpose of this study was to characterize patients who play tennis after undergoing hip arthroplasty in terms of their functional abilities and degree of satisfaction. A questionnaire was sent to all United States Tennis Association member associations in a tri-state area to identify players who had undergone a hip arthroplasty. The study group had 50 men and 8 women with a mean age of 70 years (range, 47 to 89). Only 14% of the patients' surgeons approved this tennis activity, with 34% of the surgeons recommending only doubles. Three patients required revision surgery after a mean of 8 years. One year after arthroplasty, players played both singles and doubles approximately three times per week. All tennis players were extremely satisfied with their hip arthroplasties and their increased ability to participate in their favorite sport. Because this study was confined to association members, further studies are needed to assess the general effect of tennis on total hip arthroplasty. Until future studies are performed, the authors would recommend that physicians advise caution in tennis activities and to carefully follow their patients yearly to see if osteolysis is occurring prematurely.

Aged↗