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Biomedical subjects

L B Engesaeter

Publications and source records attributed to L B Engesaeter.

At least 37 records · Page 2Linked to original sources
PubMed1996

The economic impact of failures in total hip replacement surgery: 28,997 cases from the Norwegian Arthroplasty Register, 1987-1993.

The Norwegian Arthroplasty Register was established in 1987. Until January 1994, approximately 200 different implant combinations had been used in total hip replacements (THR) in Norway. About 5,500 THR were performed each year in this period with a total cost of 70 million USD per year. We analyzed the economic consequences related to the use of some inferior primary hip arthroplasties in this period. As the reference arthroplasty, we chose the most commonly used prosthesis in Norway, i.e., the Charnley prosthesis fixed with high viscosity cement containing antibiotic and with systemic antibiotic prophylaxis (n 4,970). We compared this reference group to all other primary THR registered in the same time period (n 24,027), and to the following sub-groups of primary THR: 1) uncemented Ti-Fit/ Bio-Fit (acetabulum/femur) combination (n 173), 2) uncemented Coxa/Femora combination (n 153), 3) THR with low-viscosity cement (n 1,807) and 4) THR with Boneloc cement (n 1,250). We estimated the number of additional revisions compared to the reference arthroplasty after a follow-up of 3-5 years in the different groups, with adjustment for age, sex and diagnosis. The direct extra revision costs were calculated. Compared to the reference arthroplasty, the group of all other primary THR gave an extra revision cost estimated at about 1.7 million USD per year. About 1,000 uncemented Bio-Fit femoral prostheses have been applied in Norway, including those implanted before the registration started (1985-1987). The extra revision costs the first postoperative years for these 1,000 prostheses amount to about 0.7 million USD per year. Corresponding figures in the Coxa/ Femora group were 0.08 million USD, in the group with low-viscosity cement, 0.3 million USD and in the Boneloc group, 0.4 million USD per year.

Aged↗
PubMed1995

The effect of the type of cement on early revision of Charnley total hip prostheses. A review of eight thousand five hundred and seventy-nine primary arthroplasties from the Norwegian Arthroplasty Register.

We studied the survival of 8579 Charnley prostheses, in 7922 patients, according to the different types of cement that had been used. All of the patients had had a primary total hip replacement for primary coxarthrosis. The mean duration of follow-up was 3.2 years (range, zero to 6.4 years). The data were collected from the national Norwegian Arthroplasty Register. The duration of survival was defined as the time to revision due to aseptic loosening. The Kaplan-Meier estimate of survival at 5.5 years for the 1226 femoral components that had been implanted with low-viscosity cement was 94.1 per cent (95 per cent confidence interval, 92.1 to 96.2 per cent), compared with 98.1 per cent (95 per cent confidence interval, 97.5 to 98.6 per cent) for the 6589 components that had been implanted with high-viscosity cement (p < 0.0001). The remaining 764 femoral components had been implanted with Boneloc cement, which was classified as neither high nor low-viscosity, and these components were considered as a separate group in the analyses. The Boneloc cement had been used for only three years, and the two-year survival rate of these prostheses was 95.5 per cent (p < 0.0001). The cement contained an antibiotic in 2801 (42 per cent of the hips in which the femoral component had been implanted with high-viscosity cement, compared with only thirty (2 per cent) of those in which it had been implanted with low-viscosity cement.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1995

Early revision among 12,179 hip prostheses. A comparison of 10 different brands reported to the Norwegian Arthroplasty Register, 1987-1993.

On the basis of data from the Norwegian Arthroplasty Register during the period 1987-1993, we have compared times to revision for 10 different cemented total hip prostheses. A total of 11,169 patients, with 12,179 primary total hip replacements (THRs), performed with high viscosity cement for primary arthrosis and followed for a maximum of 6.4 years, were included in this study. The Kaplan-Meier estimate of the overall percentage revised after 5 years was 2.5 (95% Confidence Interval: 2.1-3.0). For the Charnley prosthesis (n 6,694), 2.9% were revised after 5 years (95% CI: 2.3-3.4). Using Cox regression to adjust for gender, age, type of cement and use of systemic antibiotic prophylaxis, the Charnley prosthesis was compared with the 9 other brands. The revision rate for the Spectron/ITH combination (Spectron acetabulum, ITH femur) (n 1,034) was only 0.35 (p 0.04) times that of the Charnley prostheses. The Elite/Charnley combination (Elite acetabulum, Charnley femur) (n 507) and the Müller Type prosthesis (n 116) showed poorer results with failure rates 2.3 (p 0.01) and 2.7 times (p 0.04) that of Charnley, respectively. Although the overall results for cemented THRs in general were good, clinically important differences in revision rates were demonstrated among the cemented prosthesis brands. Our findings underline the need for careful evaluation of different total hip replacements.

Hip Prosthesis↗
PubMed1995

Revision for aseptic loosening of uncemented cups in 4,352 primary total hip prostheses. A report from the Norwegian Arthroplasty Register.

From September 1987 until January 1994 the Norwegian Arthroplasty Register recorded 5,021 primary total hip replacements performed with uncemented acetabular components. We compared the survival until revision for aseptic loosening of the cup, in the 11 commonest types (n 4,352). The overall cumulative revision rate for the acetabular components was 3.2% after 5 years and 7.1% after 6 years, with large differences among the designs. With the hydroxyapatite (HA)-coated cups and the hemispheric porous-coated cups, the failure rate was less than 0.1%. Of the unthreaded hemispheric porous-coated cups, Harris-Galante and Gemini (n 626), none had been revised, and of the HA-coated cups, Atoll and Tropic (n 1,943), only 1 had been revised. For the threaded uncoated metal-backed cups, the results varied from no revisions of the PM cups (n 148) to a cumulative 6-year revision rate of 21% for the Ti-Fit (n 300). The all-polyethylene Endler cups (n 334) had a cumulative revision rate of 14%. Women and patients with inflammatory arthritis had poorer results. However, the type and the design of the cups were of far greater importance for the results than patient-related factors.

Acetabulum↗
PubMed1995

Early aseptic loosening of uncemented femoral components in primary total hip replacement. A review based on the Norwegian Arthroplasty Register.

The Norwegian Arthroplasty Register recorded 24,408 primary total hip replacements from 1987 to 1993; 2907 of them (13%) were performed with uncemented femoral components. We have compared the results of eight different designs, each used in more than 100 patients. Survivorship of the components was estimated by the Kaplan-Meier method using revision for aseptic loosening of the femoral component as the end-point. At 4.5 years, the estimated probability of revision for aseptic loosening for all implants was 4.5%, for the Bio-Fit stem 18.6% (n = 210) and for the Femora stem 13.6% (n = 173). The PM-Prosthesis and the Harris/Galante stem prostheses needed revision in 5.6% and 3.6%, respectively. The clockwise threaded stem of the Femora implant needed revision in 20% of right hips, but in only 4% of left hips. The short-term results of the four best uncemented femoral components (Corail, LMT, Profile and Zweimüller) were similar to those for cemented stems, with revision for loosening in less than 1% at 4.5 years. The importance of the control of innovative designs and the registration of early results is discussed.

Adolescent↗
PubMed1994

Early failures among 14,009 cemented and 1,326 uncemented prostheses for primary coxarthrosis. The Norwegian Arthroplasty Register, 1987-1992.

In the Norwegian Arthroplasty Register, 15,335 primary total hip replacements (THR) in patients with primary arthrosis were followed for 0-5.4 years. The Kaplan-Meier estimate of cumulative failure (revision) after 4.5 years was 2.7 percent for cemented THR, compared to 6.5 percent for uncemented. In patients under 65 years the cumulative revisions for cemented and uncemented THR were 3.3 and 7.9 percent. For the acetabular components, the cumulative failures were 0.6 percent for cemented and 1.7 percent for uncemented, and for femoral components 1.7 and 3.9 percent after 4.5 years. Adjusting for age and sex using a Cox regression model, 2 times higher rates of failure were found comparing uncemented to cemented THR. The results for uncemented prostheses were more unfavorable in young patients. In men and women under 60, the revision rates were increased 6 and 3 times, respectively, for patients with uncemented THR compared to those with cemented THR. Restriction of the end-point to revision for aseptic loosening gave results similar to the over-all results. No difference between cemented and uncemented THR was seen for revisions due to infection, whereas the most unfavorable results for uncemented THR were seen when revisions due to causes other than infection and aseptic loosening were considered.

Adult↗
PubMed1993

The Norwegian arthroplasty register. A survey of 17,444 hip replacements 1987-1990.

In Norway a national register for total hip replacements was established in September 1987. Up till February 1991, 17,444 total hip replacements (THR) were reported, i.e., 140 THR/100,000 inhabitants/year. The median age of the patients was 70 years, and 69 percent were women. 87 percent were primary arthroplasties and 13 percent were revisions. Primary arthrosis was the diagnosis in 68 percent of the primary operations. The acetabular implants were uncemented in 17 percent and the femoral implants in 12 percent of primary operations. In revisions, the implants were uncemented in 21 and 17 percent, respectively. The reasons for revision were loosening of components in 87 percent and deep infection in 4 percent. The Charnley prosthesis dominated with 49 percent of all implants. A total of 422 different designs and sizes of acetabular implants, 398 femoral implants and 166 of caput designs and sizes were used. This large number of different types and designs seems unreasonable.

Adolescent↗
PubMed1992

[Artificial hip joints in Norway. A national registry of total hip arthroplasties].

The Norwegian national register for total hip replacements collects data on the total hip arthroplasties performed in Norway. 17,444 operations were registered from the start i September 1987 and through 1990. The age of the patients ranged from 12 til 97 years. The median was 69 years. 69% of the patients were females. The operating-time ranged from 25 to 420 minutes, with a median of 100 minutes. Cemented prostheses constituted 83% and uncemented prostheses 17% of the market. The Charnley prosthesis dominated, and was used in 49% of all implants. 13% of all operations were revisions. During these three and a half years, 0.9% of the cemented prostheses and 2.9% of the noncemented prostheses were revised (P less than 0.001).

Adolescent↗
PubMed1992

Fracture healing in rats inhibited by locally administered indomethacin.

We studied the inhibitory effect of indomethacin on fracture healing in 135 young, male rats after oral administration compared with local application into the fracture. A closed mid-diaphyseal fracture of the left femur was performed in all the rats. The fractures were not immobilized. In one experiment, half of the animals received indomethacin via a stomach tube (2 mg/kg/day) for 10 days; the controls received only the vehicle. In another experiment, 0.5 mg of indomethacin, contained in a bioerodible polyorthoester gel, was injected into the fracture area in half the rats; in the controls, only the gel was injected. In both experiments, random animals were killed on Days 0, 5, 10, and 20. As assessed by radiographs and manual testing, the same inhibition of fracture healing was found regardless of whether indomethacin was given orally or locally. However, the amount of indomethacin that was applied locally was only one fourth of the total dose given orally; no indomethacin was detected in the serum.

Administration, Oral↗
PubMed1992

Effects of intramedullary reaming and nailing on blood flow in rat femora.

The right femur in 40 rats was reamed, and in 40 others it was additionally nailed. Analysis of bone blood flow was performed by the distribution of radiolabeled microspheres at different postoperative time intervals. Blood-flow measurements were accompanied by analyses of hydroxyproline and calcium contents. Immediately after reaming, the blood flow of the diaphyseal part of the femur was reduced to approximately one third of that of the intact femur, whereas the contents of hydroxyproline and calcium were reduced by 10 percent. Within 1 week, the blood flow was normal. This study provides evidence that the presence of a nail does not interfere with the restoration of bone blood flow. Restoration of blood flow in bone apparently is a rapid process. The replacement of hydroxyproline and calcium contents seemed to be linked to flow, as no increase in these constituents were found until the blood flow had approximated the level of the intact femur.

Animals↗
PubMed1991

Effects of intramedullary reaming and nailing of rat femur. A mechanical and chemical study.

This study was undertaken to explore the association between mechanical and chemical effects of intramedullary reaming and nailing. The right femora of 80 rats were reamed and nailed with steel nails. Forty rats were evaluated from 3 days to 24 weeks postoperatively. The other 40 rats had the nail removed after 12 weeks, and they were then followed from 3 days to 24 weeks after nail extraction. Evaluation consisted of in vivo strain recording, geometric measurements, mechanical three-point bending test, and chemical analyses of hydroxyproline and calcium contents. Reaming and nailing caused immediate weakening of the bone as measured by in vitro mechanical tests, but within 3 weeks the mechanical properties were fully restored, whereas in vivo strain remained reduced throughout the experimental period in rats with nails. Removing the nail increased in vivo strain to a level close to that of the intact femur. Remodeling of the bone resulted in greater external anteroposterior diameter, cross-sectional area, area moment of inertia, and amount of hydroxyproline and calcium in the operated on femur as compared with the intact side. This indicates that the repair processes resulted in greater bone mass of the operated on femur than of the intact femur. Thus, there is evidence that nailing techniques effectively assist tissues by repair and remodeling.

Animals↗
PubMed1991

Age-related differences in chemical composition of rat femur as determinants for strain.

We have explored previous findings of remarkably stable in vivo strain at the femoral surface in rats at different ages, and at the same time increased bone stiffness. The rate of collagen synthesis (14C-hydroxyproline/total hydroxyproline ratio) decreased with age, whereas mineralization (calcium/hydroxyproline ratio) increased. Smaller amounts of immature collagen, caused by reduced synthesis, and increased mineralization both probably produce a less flexible material. These chemical alterations support the observed increase in structural stiffness and strength with age. Both mineralization and configurations separately seemed to have effects on in vivo strain. However, none of these variables seemed to be the major determinant for strain.

Aging↗
PubMed1990

Ultrasound and congenital dislocation of the hip. The importance of dynamic assessment.

One-hundred newborn children at high risk of hip instability were prospectively assessed clinically and by ultrasound. The decision to treat was based only on the clinical examination. At the age of three months all the children were evaluated clinically and with an anteroposterior radiograph of the pelvis. None of the standard ultrasound measurements of acetabular depth and femoral head cover correlated with the outcome at three months. Dynamic assessment of stability was the only ultrasound technique that had a significant relation with outcome.

Female↗
PubMed1985

Consumption of hospital resources for hip fracture. Discharge rates for fracture in Norway.

The hospital discharge rate for the period 1977-1981 in a population of 1.08 million was 1.91 per 1000 inhabitants for hip fractures and 3.89 for other fractures (skull fractures excluded). Discharges for fractures constituted 4.3 per cent of the discharges from the somatic hospitals. Hip fracture consumed one fourth of all somatic hospital bed-days for the oldest patients.

Adult↗
PubMed1985

Meniscus repair in knee ligament injuries.

One hundred and fifteen primarily operated patients with medial collateral ligament tears of the knee have been reviewed. Two-thirds of the patients had associated cruciate ligament injuries. In 59 knees, injuries of the medial meniscus were found. Suture of the medial meniscus was performed in 53 patients, while medial meniscectomy was done in only six cases. Knee function was evaluated by follow-up after 4 (2-8) years. Excellent or good results as evaluated by the Lysholm knee score were obtained in 86 per cent of the patients, with equally good results in those with meniscus suture as compared to those without meniscus injury. No secondary meniscectomies were performed.

Adolescent↗
PubMed1984

Effects of a distal venting hole in the femur during total hip replacement.

In 18 patients who underwent total hip replacement, the intramedullary pressure in the femur was measured during the insertion of the femoral prosthesis component. Half the patients had a pressure release hole (diameter 4.5 mm) drilled into the medullary canal at the distal end of the femur, the other half not. In the patients without a venting hole, the intramedullary pressure increased transiently to a median of 390mmHg during the insertion of the femoral stem, while those with a venting hole only showed an increase to 23mmHg. A drop in arterial oxygen tension of 2.2kPa and in thrombocytes of 51 x 10(9)/1 was found in those without a venting hole, while the corresponding values in those with a venting hole were 0.9kPa and 20 x 10(9)/1. Furthermore, a significant correlation was demonstrated between the increase in intramedullary pressure and the drop in oxygen tension and in blood platelets. No significant change in blood pressure was measured during operation in either group.

Aged↗
PubMed1984

Torsional properties of rat femora.

The torsional behaviour of the femur has been studied in 145 male Wistar rats, aged 3-36 weeks. The ultimate torsional moment and the torsional stiffness of the femora increased with increasing animal age. In contrast, the femoral deformation at failure, the ultimate torsional angle, was almost constant for all age levels. The strength and stiffness of cortical bone as a material, the ultimate torsional stress and the modulus of rigidity reached a plateau when the rats were about 14 weeks old, and had a body weight and femoral length of about 350 g and 35 mm, respectively. In conclusion, cortical bone of Wistar rats probably reaches maturity at an age of about 14 weeks.

Aging↗