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Biomedical subjects

A Stenström

Publications and source records attributed to A Stenström.

At least 19 recordsLinked to original sources
PubMed1992

The influence of metal backing in unicompartmental tibial component fixation. An in vivo roentgen stereophotogrammetric analysis of micromotion.

The fixation of the tibial component in 36 patients with conventionally cemented unicompartmental knee arthroplasties for femorotibial gonarthrosis was studied using roentgen stereophotogrammetric analysis (RSA). Twenty-four tibial components were all-polyethylene while 12 were metal-backed. The follow-up was for 6 years. Significant migration was detected for all cases but two and ranged from 0.3 mm to 5.4 mm. The greater part of the migration occurred during the first 1-2 years, after which two-thirds of the prostheses remained stable. Seven all-polyethylene components were subjected to a stress examination after 1-2 years and displacement, induced by external forces, was found in all seven. A strong correlation was found between the extension of the radiolucent line and the migration. Otherwise, neither demographic, clinical, nor radiographic data correlated with the RSA results. In this study metal backing did not have any influence on prosthetic fixation as measured by RSA.

Aged↗
PubMed1992

Knee arthroscopy using local anesthesia.

This study confirms the feasibility of performing arthroscopy and arthroscopic surgery with patients under local anesthesia. Seventy patients underwent arthroscopy under local anesthesia using mepivacaine with adrenaline. In 49 patients, arthroscopic surgery was performed. It is important to wait at least 20 min after the injection of the anesthetic before surgery to anesthetize the medial part of the joint. There were few complications. Diagnostic and surgical arthroscopy can be successfully performed in the majority of patients with local anesthesia.

Adult↗
PubMed1992

Multicenter study of unicompartmental knee revision. PCA, Marmor, and St Georg compared in 3,777 cases of arthrosis.

The prospective Swedish Knee Arthroplasty Project contained 772 PCA, 1564 Marmor and 1441 St Georg unicompartment prostheses, implanted for gonarthrosis during the period December 1983-July 1990. Follow-up was performed in September 1991. There was a significant difference in the cumulative revision rate after only 2 years, increasing to 15 percent for the PCA, compared with 5-7 percent for the two other types. The difference between PCA and Marmor/St Georg was loosening of the femoral component. Major polyethylene wear was noted in a quarter of the revised PCA tibial components. The wear pattern of Marmor/St Georg was not analyzed in this study.

Actuarial Analysis↗
PubMed1992

Polyethylene wear of the PCA unicompartmental knee. Prospective 5 (4-8) year study of 120 arthrosis knees.

In Lund, 120 arthrosis knees had the PCA unicompartmental endoprosthesis during 1983-1987 and were followed prospectively for 5 (4-8) years. 17 knees were excluded from the final clinical follow-up because of the development of rheumatoid arthritis (2), severe neurologic disease (3), or death (12). Subjectively, 68 knees were much improved, 26 improved and 9 had failed. First-steps problems were only present in the uncemented group of 49 knees. Of the 9 failures (7 cemented and 2 uncemented) 6 were revised. The main reason for revision was loosening of the femoral component (2), tibial component (2), or both components (1), and polyethylene wear (1). However, all revised tibial components showed polyethylene wear, in 4 quite pronounced. Weight-bearing radiographs (61 knees) revealed major polyethylene wear in an additional 14 knees; not only in thin tibial components. There may be an increasing clinical problem due to polyethylene wear. With the presented findings the PCA unicompartmental knee endoprosthesis cannot be recommended.

Aged↗
PubMed1991

Temporal studies of the inhibition of voluntary ethanol intake in the rat induced by intermittent ethanol treatment and some long term neurochemical consequences.

Male rats were injected with ethanol (groups 3 and 5; 2.0 g/kg i.p.) or saline (groups 2 and 4) once a week for 52 weeks. The rats had access to ethanol as a voluntary choice for 24 h either once 6 days after the injection (groups 2 and 3) or twice 3 and 6 days after the injection (groups 4 and 5). At the beginning of the treatment ethanol injections inhibited voluntary ethanol intake if tested 6 days later (groups 3 and 5), but a tolerance developed to this inhibition. During tolerance development the rats in group 5 also drank less ethanol on day 3 than on day 6. No corresponding behaviour was seen in group 4. Thus part of the tolerance was a gradual reduction of the duration of inhibition. During the evaluation period (25 weeks) after the treatment, ethanol exposure (20 weeks) consisted of a continuous choice between ethanol and water. Of different ethanol concentrations both ethanol-injected groups (3 and 5) took the same voluntary dose of ethanol independent of the offered concentration. After 5 weeks without ethanol all rats were killed and a number of neurochemical variables were determined. Compared with almost unexposed rats (group 1) changes were seen in inositol phospholipid breakdown, muscarinic binding sites in hippocampus, noradrenaline concentrations in frontal cortex, hippocampus and hypothalamus, dopamine concentration in frontal cortex and 5-hydroxytryptamine concentration in hypothalamus. In most cases the largest changes were seen in group 5. None of the variables had a constant relation to ethanol intake in the total population. However, significant correlations were found in some of the groups.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Effect of L-dopa administration on islet monoamine oxidase activity and glucose-induced insulin release in the mouse.

Previous studies have shown that the amine precursor L-3,4-dihydroxyphenylalanine (L-DOPA) is rapidly converted to its corresponding amine, dopamine, in islet beta-cells. In the present investigation, we studied the effect of acute L-DOPA administration on islet monoamine oxidase (MAO) activity and on glucose-induced insulin secretory response in mice. It was observed that at 2 min after intravenous L-DOPA administration, there was a marked increase (+35%) in islet MAO activity, with serotonin as substrate. At 7 min, MAO activity towards dopamine was enhanced by 32% and that towards serotonin and phenylethylamine (PEA) was decreased by 23 and 25%, respectively. The inhibitor of L-aromatic amino acid decarboxylase, benserazide, abolished L-DOPA-induced changes of MAO activity, suggesting that the formed dopamine, and not L-DOPA itself, was responsible for the observed effects. At 60 min, no effect by L-DOPA administration on islet MAO activity was noticed. L-DOPA (125 or 250 mumol/kg), given together with glucose, induced a decrease in glucose-induced insulin response. L-DOPA (125 mumol/kg), given 7 min before glucose, totally suppressed glucose-induced insulin response. This inhibition was eliminated through pretreatment with benserazide. Enhancement of glucose-stimulated insulin response, after deposition of horseradish peroxidase (HRP) in beta-cell vacuolar system, was suppressed by L-DOPA. We conclude that acute L-DOPA-induced dopamine accumulation in pancreatic islets is accompanied by rapid changes in MAO activity, concomitant with an inhibitory effect on glucose-stimulated insulin response. Increased hydrogen peroxide production, following increased MAO activity, may possibly augment the inhibitory effect of dopamine accumulation on insulin release.

Animals↗
PubMed1990

Topical treatment of necrotic foot ulcers in diabetic patients: a comparative trial of DuoDerm and MeZinc.

An open randomized controlled study was carried out of 44 diabetic patients with necrotic foot ulcers treated with adhesive zinc oxide tape (MeZinc) or with an adhesive occlusive hydrocolloid dressing (DuoDerm). Fourteen of the 21 patients treated with MeZinc had their necrotic ulcers improved by at least 50% compared to six out of 21 with the hydrocolloid dressing (P less than 0.025). Fifteen patients showed an increase in the area of necrosis during the course of the 5-week study and of these, 10 had been treated with the hydrocolloid dressing.

Administration, Topical↗
PubMed1990

The treatment of tarsometatarsal injuries.

In order to analyze the value of operative treatment for tarsometatarsal injuries, 31 consecutive fracture-dislocation injuries from 1975 to 1988, and 11 cases of undislocated injuries were reviewed. Forty patients (41 injuries) could be contacted. The average follow up was 5 years. Twenty-two of the dislocated injuries were treated with open reduction and fixation, usually K-wires. All injuries were classified radiologically. By means of a questionnaire, it was found that 7 had excellent results, 13 good, and 21 poor. No case where anatomical reduction was not achieved could be classified as excellent, and half (5 of 10) received full disability pension. When anatomical reduction was achieved, half had good or excellent results and only 5 of 20 received a disability pension. Initially undislocated injuries had a better prognosis, with 8 of 11 having excellent or good results, and none receiving pension. These injuries should be treated aggressively with open reduction and fixation when there is any displacement. Despite this treatment, one-half of patients with dislocated injuries as well as one-fourth of those with initially undislocated injuries will still suffer from pain and permanent disability probably due to soft tissue damage and instability.

Adolescent↗
PubMed1990

Cold flow reduced by metal backing. An in vivo roentgen stereophotogrammetric analysis of unicompartmental tibial components.

Thirty-six cases of unicompartmental arthroplasty for gonarthrosis were followed for 6 years. The arthroplasties were prepared for roentgen stereophotogrammetric analysis (RSA) by marking the tibial components and the tibial methaphysis with tantalum balls. Nineteen out of 24 cases with a polyethylene tibial component had an increase in intermarker distances signifying progressive enlargement of the prosthesis due to cold flow. The enlargement was up to 2.8 percent of the circumference and was greater for 9 mm than for 12 mm thick components. Twelve cases with a metal-backed tibial component showed no cold flow. No correlation between cold flow and demographic, clinical, or radiographic data was found.

Aged↗
PubMed1990

Porous coated anatomic tricompartmental tibial components. The relationship between prosthetic position and micromotion.

Micromotion of the tibial component, both as migration over time and as inducible displacement in response to external physiologic forces, was studied in 20 cases of gonarthrosis. The patients had Porous Coated Anatomic primary total knee arthroplasty and were followed for four years. All cases but one were clinically successful. Thirteen components were inserted without cement, while in seven, high-viscosity Palacos cement was used. Full postoperative weight bearing was allowed in all cases. During the first year, noncemented components migrated a mean of 2.6 mm, while cemented components migrated a mean of 1.1 mm. About 1 mm of migration of noncemented components was in the downward direction, i.e., subsidence occurred, mostly during the first year. After one year, the noncemented components had stabilized more than the cemented ones. There was a significant correlation between the migration after one year and the postoperative prosthetic position and alignment of the leg. A mean maximum inducible displacement (the total vector displacement of the prosthetic marker that moved the most) of 0.7 mm and 0.4 mm was found for noncemented and cemented components, respectively. The micromotion found was of the same magnitude as that for other cemented and noncemented prosthetic systems previously reported.

Aged↗
PubMed1990

A long-term follow-up study of total meniscectomy in children.

The long-term effects of single meniscectomy in 89 children have been analyzed at an average of 16.8 years after surgery. Seventy-four percent were pleased with the outcome, but only 52% or 58% had objectively satisfactory results according to the two scoring systems used. Significantly poorer results were achieved with lateral meniscectomies. The range of movement was significantly decreased after lateral meniscectomy. Minor instabilities were recorded in 45% of the patients and major instabilities in 15%. Anteroposterior and rotatory instabilities were objectively measured, and a significant increase was noted in knees that had lateral meniscectomy. Grade I gonarthrosis was recorded in 39% of the surgically treated knees and Grades II and III gonarthroses in 9%. The joint space was significantly reduced in all knees irrespective of the injured compartment.

Adolescent↗
PubMed1989

Wound classification is more important than site of ulceration in the outcome of diabetic foot ulcers.

The importance of wound classification and site of ulceration was evaluated in 314 consecutive diabetic patients with foot ulcers. The ulcers were classified as superficial (through the full thickness of the dermis; n = 150), deep (n = 50), osteomyelitis and/or abscess (n = 46), minor gangrene (n = 39) or major gangrene (n = 29). Wound healing was defined as intact skin for at least 6 months. In patients with superficial and deep ulcers, primary healing occurred in 88% and 78%, respectively, compared with 57% in those patient who developed an abscess and/or osteomyelitis. Only 2 out of 68 patients with gangrene healed (through mummification) without amputation. Patients with gangrene had lower ankle and toe blood pressure than patients with all other types of ulcers. There were only marginal differences in primary healing rate between different ulcer sites. The highest rate was seen in ulcers localized to the metatarsal heads (78%). Patients with multiple ulcers had the lowest primary healing rate (5%) compared with single ulcers at all sites. These differences were probably due to circulatory factors, since patients with multiple ulcers had lower distal perfusion pressures compared with all other groups.

Blood Pressure↗
PubMed1989

Comparison of intra- and extrasynaptosomal monoamine oxidase-A and -B activities in the striatum and frontal cortex of two mice strains with different sensitivities to the neurotoxic actions of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

Conditions for the assay of the intra- and extrasynaptosomal rates of deamination of dopamine and noradrenaline by the two forms of monoamine oxidase (MAO) have been determined in striatal and frontal cortical homogenates, respectively, from C57 BL/6 mice. The activities obtained were compared with the corresponding activities found for NMRI mice, a strain less sensitive to the neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) than the C57 BL/6 strain. In both strains, the intra- and extrasynaptosomal deamination of dopamine in the striatal homogenates was brought about predominantly by MAO-A. No significant differences between the two strains were found for the intra- or extrasynaptosomal MAO-A or -B activities towards dopamine in striatal homogenates. On the other hand, the striatal dopamine concentrations were higher in the C57 BL/6 mice than in the NMRI mice. The concentrations of the dopamine metabolites DOPAC and HVA were similarly higher, suggesting that the rate of turnover of dopamine is the same for the two strains. In frontal cortical homogenates, MAO-A predominated in the deamination of noradrenaline both intra- and extrasynaptosomally. The extrasynaptosomal rates of deamination of noradrenaline were similar in the two mice strains, whereas the intrasynaptosomal MAO-A activity was significantly higher for the C57 BL/6 mice. These results concur with and extend to the noradrenergic system the conclusion previously made by Jossan et al. (1987) for the dopaminergic system that although MAO-B activity is necessary for expression of MPTP neurotoxicity, it is not the rate-limiting step for the development of the neurotoxic effects.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1989

Proximal closing wedge osteotomy and adductor tenotomy for treatment of hallux valgus.

After 2 to 4 years, 25 patients (27 feet) who had a proximal closing wedge osteotomy of the first metatarsal and an adductor tenotomy were reviewed. A total of 20 patients (22 of 27 feet) were completely satisfied; 5 patients not completely satisfied had metatarsalgia because of dorsal displacement of the first metatarsal head. Radiographic measurements showed a narrowing of the forefoot rather than a large change in the intermetatarsal angle. The recovery period was long, an average of 11 weeks. Pin inflammation occurred in 5 patients and incisional neuromas in 2 patients. The risk of these complications must be taken into consideration when using this operation.

Adult↗
PubMed1989

Prognostic value of systolic ankle and toe blood pressure levels in outcome of diabetic foot ulcer.

The prognostic value of distal blood pressure measurements has been studied in 314 consecutive diabetic patients with foot ulcers. Systolic toe blood pressure was measured with a strain-gauge technique, and ankle pressure was measured with strain-gauge or Doppler techniques. Wound healing was defined as intact skin for at least 6 mo. One hundred ninety-seven patients healed primarily, 77 had amputations, and 40 died before healing had occurred. In 294 of 300 patients, it was possible to measure either ankle or toe pressure. Fourteen patients were not available for pressure measurements. Of these, 10 patients healed primarily, and 4 died before healing occurred. Both ankle and toe pressures were higher (P less than .001) among patients who healed without amputation compared with those who underwent amputation or died before healing. No differences were seen in ankle or toe pressure levels among those who had amputations or died. No patient healed primarily with an ankle pressure less than 40 mmHg. An upper limit above which amputation was not required could not be defined. Primary healing was achieved in 139 of 164 patients (85%) with a toe pressure level greater than 45 mmHg, whereas 43 of 117 patients (36%; P less than .001) healed without amputation when toe pressure was less than or equal to 45 mmHg. In conclusion, a combination of ankle and toe pressure measurements is a useful tool to predict primary healing in diabetic foot ulcers.

Aged↗
PubMed1989

Fluorescein angiography for predicting healing of foot ulcers.

Fluorescein angiography (FA) was performed on 83 patients (68 diabetics) with foot ulcer or gangrene. Densitometric measurements were made on the FA images, and different FA parameters were defined. These parameters, as well as systolic ankle and toe blood pressures, were evaluated for predicting the future course, i.e., whether healing would occur or whether major amputation below or above the knee had to be performed. The toe slope (i.e., the rate of increase of fluorescence on the big toe during the first 10 seconds after its appearance on the toe) predicted healing correctly in 0.83 and major amputation in 0.88. The ankle and toe pressures had only slightly lower predictive value. The combination of ankle pressure and toe slope predicted healing correctly in 0.91 and major amputation in 0.88. When ankle pressure cannot be measured, FA is the method of choice. Further, FA provides information on regional blood flow unobtainable by any other method.

Adult↗