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Biomedical subjects

P T Nielsen

Publications and source records attributed to P T Nielsen.

At least 19 recordsLinked to original sources
PubMed1999

[Treatment of malignant parotid tumors. Results from the county of Copenhagen].

Out of 494 parotid gland tumours treated in Copenhagen county (population 600,000 inhabitants) in the period 1986 to 1995, 50 patients (tumours) were proven to be malignant, making an incidence of 0.62/100,000 per year. Age ranged between 14 and 87, mean 64 years. According to the UICC classification system, six tumours (12%) were classified as stage I, 23 (46%) as stage II, 14 (28%) as stage III and 7 (14%) in stage IV. Four therapeutic modalities were applied: surgery only, surgery + radiation, surgery + chemotherapy and surgery + chemotherapy + radiation. Surgical radicality was achieved in 76% and radicality was unrelated to tumour histology. Normal or nearly normal facial nerve function (HB1&2) was noted at last follow up in 60%. Five year crude survival for all patients were 68%. Survival was not depends on N-classification. Patients in stage I had a better survival compared to patients in stage II, III and IV. No statistically significant difference in five year crude survival between the radically operated patients (n = 38) and patients with residual tumour (p = 0.27, log rank-test), (p = 0.48 chi2-test was found.

Adolescent↗
PubMed1999

Preoperative bone mineral density of the proximal tibia and migration of the tibial component after uncemented total knee arthroplasty.

Twenty-two patients with primary osteoarthrosis of the knee all operated on with insertion of an uncemented total knee arthroplasty had a preoperative measurement of bone mineral density (BMD) in the coronal plane of the proximal tibia performed by dual-photon absorptiometry. Postoperatively and with follow-up after 6 weeks (n = 21), 1 year (n = 22), and 3 years (n = 19), radiographs suitable for radiostereometric analysis of the tibial component migration were obtained. One year postoperatively, stress examinations were performed with the aim of measuring inducible displacement of the tibial component. Most of the migration, expressed as maximal total point motion (MTPM), occurred during the first year with an average migration of approximately 1 mm. Regression analysis showed a positive relation between BMD and MTPM after 6 weeks (P = .03, r = .47), 1 year (P = .0005, r = .68), and 3 years (P = .02, r = .54). Inducible displacement did not reveal any significant relation to BMD. MTPM between 1 and 3 years, which is the clinically most important parameter with respect to later loosening of the tibial component, showed a negative relation to BMD (P = .04, r = -.47). Thus, tibial components of knees with preoperative high tibial BMD showed less continuous migration.

Aged↗
PubMed1998

Patient survival after total knee arthroplasty. 5-year data in 926 patients.

We analyzed prospectively the 5-year survival in 926 patients undergoing 1,024 total knee arthroplasties (TKA) in the period February 1989-December 1990. The patients were compared to an age- and sex-matched general population and to 326 patients operated on in the same period with total hip arthroplasty. Cox analysis showed that male sex, rheumatoid arthritis and complications within the first year increased the mortality rate in the TKA group. When this group was compared to the general population, only rheumatoid patients aged 65-74 years had an increased mortality. Generally, the TKA patients had a longer survival than the general population, especially women > 75 years old with arthrosis. The cumulative 5-year patient survival was 89%, both after hip and knee arthroplasty and was 81% in the matched general population.

Adult↗
PubMed1998

Epidemiology of ankle fractures. A prospective population-based study of 212 cases in Aalborg, Denmark.

We studied the epidemiology of ankle fractures prospectively during 1 year in a population of about 200,000. The overall incidence rate was 107 fractures per 10(5) person-years. Below the age of 50, ankle fractures were commonest in men. After this age, females became predominant and the age-specific incidence rates decreased in both sexes. The main cause of fracture was falls (87%), on the ground, on stairs or from a height. 137 fractures (55%) occurred in sports, play or other leisure activities. Most patients (64%) were walking, running or jumping at the time of injury. Alcohol and slippery surfaces were each involved in nearly a third of the cases. The distribution of the fractures according to both the Lauge-Hansen and the AO Weber classification systems were within the limits of previous series. Nearly half the patients were hospitalized and the fractures were operated on with osteosynthesis. Our findings indicate that ankle fractures are mainly caused by substantial trauma sustained during physical activity. Osteoporosis seems to be of minor importance.

Adolescent↗
PubMed1996

The relation between trabecular bone strength and bone mineral density assessed by dual photon and dual energy X-ray absorptiometry in the proximal tibia.

The feasibility of two noninvasive methods [dual photon absorptiometry (DPA) and dual energy X-ray absorptiometry (DXA)] for prediction in vivo of local variations of trabecular bone strength within the proximal tibia was evaluated in 14 cadaveric knees. Trabecular bone strength was measured using an osteopenetrometer and from destructive compression tests performed on bone cylinders, thus measuring the penetration strength and ultimate strength in the medial, lateral, and central part of the tibial bone specimens. Linear regression analysis showed significant relations between BMD measured by DPA (r2 = 72%) or DXA (r2 = 73%) and ultimate strength. Even closer relations between BMD (DPA: r2 = 80%, DXA r2 = 81%) and penetration strength of trabecular bone were found. We conclude that DPA and DXA are suitable methods for evaluation in vivo of local variations in trabecular bone strength within the proximal tibia, and could easily be performed preoperatively before insertion of total knee arthroplasty.

Adult↗
PubMed1996

Cementless total knee arthroplasty in rheumatoid arthritis. A report on 51 AGC knees followed for 54 months.

Fifty-one primary consecutive cementless AGC 2000 (Anatomically Graduated Components, Biomet, Warsaw, IN) total knee arthroplasties were performed during 1985 through 1990 in 40 patients with rheumatoid arthritis. Forty-one knees (32 patients) were available for clinical and radiologic follow-up analysis after 24 to 76 months (median, 54 months). There was no pain in 33 knees and mild pain in the rest. Median range of motion was 110 degrees (range, 50 degrees-130 degrees). Median knee score was 90 (range, 71-97), and all knees were rated good or excellent. Radiolucencies greater than 1 mm were found under five tibial components, but no obvious migrations were seen. One tibial component was revised due to aseptic loosening. The cumulative success rate after 4 to 5 years was 97% (lower limit of 95% confidence interval, 91.8%). The medium-term results are considered to compare favorably with reported cemented series.

Adult↗
PubMed1996

Acute midtarsal sprains: frequency and course of recovery.

In a prospective consecutive registration of 711 ankle inversion sprains, the dorsal ligaments and capsule of the midtarsal joints were involved in 237 of the cases (33%), and in 172 cases (24%) only these joints seemed to be injured. A total of 162 isolated midtarsal injuries and 161 cases of isolated lateral talocrural lesions selected at random were followed using questionnaires 1, 3, 6, 9, and 12 months after injury. The frequencies of pain after 1 month and swelling after 1 and 3 months were significantly lower in isolated dorsal midtarsal sprains compared with isolated lateral talocrural sprains. At the following controls, frequencies of both pain and swelling were the same for both groups. Functional instability appeared with the same frequency in both groups during the 12 months of follow-up. Regarding the social impact of the sprains, absence from work and sports did not differ between groups. When avulsions were present in midtarsal injuries recovery was slow, with two thirds of the patients experiencing pain after 6 months. We conclude that the dorsal midtarsal sprain is a common entity with a course of recovery and a frequency of residual symptoms very like the lateral talocrural lesions.

Acute Disease↗
PubMed1995

Changes in bone mineral density of the proximal tibia after uncemented total knee arthroplasty. A 3-year follow-up of 25 knees.

We measured bone remodeling of the proximal tibia prospectively for 3 years after uncemented total knee arthroplasty (TKA) in 25 knees with primary arthrosis. In the trabecular bone below the tibial component, bone mineral density (BMD) was measured in 6 different regions of interest (ROI), using dual photon absorptiometry (DPA). In the tibial condyles, where the change in knee alignment indicated that the load was reduced postoperatively, a fast bone loss of 7-20% was seen during the first 6 months after surgery. A small, but significant increase in BMD of 2-7% was seen in the tibial condyles, where the load was increased. On average, the density for all ROI below the tibial component showed a significant and progressive decrease in BMD, reaching 22% at 3 years follow-up.

Absorptiometry, Photon↗
PubMed1994

Epidemiology of sprains in the lateral ankle and foot.

The epidemiology of sprains in the lateral ankle and foot was investigated in a prospective study at the casualty ward at Hillerød County Hospital. During one year, 766 patients were registered. The overall sprain incidence was 7/1000 person-years. The incidence was highest for young males. After the age of 40 years, the incidence was higher for women than for men. Most sprains were sustained during sport, but, with increasing age, other activities became dominant. Sixty-one percent of the lesions were located around the lateral ankle, and 24% were located on the lateral midfoot.

Adolescent↗
PubMed1993

The impact of static work on fibrinolysis and platelet function.

Brief stress such as dynamic work protects against thrombosis by enhancing blood fluidity. The effect of isometric work on blood fluidity, however, is not known. The aim of the present study therefore was to test the effect of isometric work on heart rate (HR), blood pressure (BP), platelet function and fibrinolytic activity. Twelve healthy male volunteers were tested before and after isometric work. Isometric work resulted in an increase in HR from 62.4 to 110.0 beats/min and in systolic BP from 118.3 to 134.5 mmHg (p < 0.01). No significant change occurred in platelet release estimated as plasma levels of B-TG and PF-4, or platelet aggregation induced by ADP. Fibrinolytic activity increased, as evidenced by a decrease in ECLT from 136.7 + 10.5 to 72.3 + 9.8 min) (p < 0.01) and an increase in t-PA of 400%. No significant change was observed in PAI. The present data suggest that isometric work increases fibrinolytic activity significantly, but leaves platelet function unchanged.

Adult↗
PubMed1993

Fracture of ceramic femoral heads in total hip arthroplasty.

Five cases of fractured ceramic heads occurring 1-2 years after primary hip arthroplasty are reported. All fractures occurred without significant trauma. As the mechanism of these failures has not been clarified, the authors have stopped using ceramic heads.

Adult↗
PubMed1992

Cementless total knee arthroplasty in unselected cases of osteoarthritis and rheumatoid arthritis. A 3-year follow-up study of 103 cases.

The authors reviewed 103 cementless AGC 2000 total knee arthroplasties in unselected cases of osteoarthritis and rheumatoid arthritis with a follow-up period of 3 years. Excellent or good clinical results were obtained in 96%. The median maximal flexion was 110 degrees. Two aseptic loosenings of the tibial components had been revised prior to this evaluation. Two other patients showed radiographic signs of tibial loosening but were asymptomatic. Undersizing of the tibial component predisposes to subsidence and loosening. One had septic tibial loosening planned for revision. Four had nonprogressive lucent lines beneath the tibial tray but were asymptomatic. No patellar or femoral component loosening was revealed. Undercorrection of preoperative varus deformity did not dispose to tibial loosening or radiolucency, nor influence the clinical result. In terms of survival of the prosthesis the cumulative success rate was 97.1%. When pain and radiographic loosening was also considered, the success rate was 90.7%. These results encourage uncemented use of this prosthesis, but emphasize the importance of good primary prosthetic fit at the tibial side.

Adult↗
PubMed1991

Antithrombotic efficacy of continuous extradural analgesia after knee replacement.

We have studied the effect of extradural analgesia on postoperative venous thrombosis in patients undergoing knee arthroplasty. Forty-eight patients were allocated randomly to receive either general anaesthesia or extradural analgesia with local anaesthetics for 3 days. All patients wore compressive elastic stockings and no anticoagulant drugs were administered. Bilateral venography was performed 10 days after surgery. Continuous extradural analgesia did not impede mobilization of the patients. One case of nonfatal pulmonary embolism occurred in a patient who received general anaesthesia. The use of continuous extradural analgesia resulted in a significant difference in the total incidence of deep vein thrombosis (18% compared with 59% after general anaesthesia (P = 0.02]. The incidence of calf vein thrombosis was 12% compared with 45% after general anaesthesia (P = 0.05).

Adult↗
PubMed1991

Histologic analysis of a retrieved hydroxyapatite-coated femoral prosthesis.

A hydroxyapatite-coated hip hemi-prosthesis was retrieved from a 98-year-old osteoporotic woman 12 weeks after implantation. Histologic analysis revealed bone and fibrous tissue almost evenly distributed around the surface of the implant circumference. Quantitative histologic analysis showed that 48% of the hydroxyapatite surface was covered by bone. Fibrous tissue covered 30% of the prosthetic surface, and 20% of the surface had no tissue coverage. Scanning electron microscopy showed direct contact without any clear boundary between the newly formed bone and the hydroxyapatite ceramic.

Aged↗
PubMed1990

[Patient related diagnostic delay in breast tumor. A prospective study].

In 209 patients referred with the diagnosis of tumour of the breast, the patient delay (PD) was registered together with the demographic and clinical conditions concerning the patient according to a meticulous questionnaire. In addition, the histological diagnosis and possible regional spread were registered. A total of 126 patients (60%) sought advice within one month of the commencement of symptoms. No statistically significant connection could be demonstrated between PD and age, marital status, education and occupational situation. No significant connection could be demonstrated between the size of the tumour, time of seeking advice and PD. A total of 115 patients (55%) had malignant tumours. The frequency of regional spread was found to be significantly greater in patients with PD longer than four weeks. Regular self-examination of the breast was undertaken by 92 (46%) of the patients and this was significantly more frequent in married or cohabiting patients, in patients with long education and in patients with employment outside the home. It did not prove possible to demonstrate briefer PD, lesser size of tumour and fewer cases of regional spread in patients who undertook self-examination of the breast but further research is required here.

Adult↗
PubMed1990

Lower thrombosis risk with epidural blockade in knee arthroplasty.

Thirty-six patients scheduled for knee arthroplasty were randomized to general or epidural anesthesia that was prolonged into the postoperative period. All the patients wore graded compression stockings until full ambulation. No other thrombo-prophylactic treatment was given. In diagnosing deep venous thrombosis, bilateral ascending venography was performed 9-11 days after surgery. The incidence of thrombosis was 2/13 in the epidural group versus 10/16 in the general anesthesia group (P less than 0.05).

Adult↗