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Biomedical subjects

K Jonsson

Publications and source records attributed to K Jonsson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Skeletal abnormalities of hands and feet in Laurence-Moon-Bardet-Biedl (LMBB) syndrome: a radiographic study.

OBJECTIVE: To identify radiological changes of the hands and feet in a large group of patients with Laurence-Moon-Bardet-Biedl syndrome. DESIGN: Postero-anterior views of hands and feet were obtained and analysed. PATIENTS: The material consists of 43 Scandinavian patients with the syndrome (24 males and 19 females; age 3 weeks to 57 years, median 23 years at the time of radiological examination). RESULTS AND CONCLUSIONS: Polydactyly of the hands and feet is one of the main criteria. This was noted clinically in 33 of 43 patients, but all but 3 had been operated on before this radiological study. Remnants of the extirpated finger or toe noted as exostoses, additional joint surfaces of duplication were found in half the hands and feet, while the remainder showed no radiological changes. Other features found were short, broad bones and flat joint surfaces of the metacarpophalangeal or metatarsophalangeal joints. We also found a high frequency of short or long ulna in relation to the radius and Madelung deformity of the wrist in several patients. Thus, the radiographs showed several non-specific normal variations besides remnants or postoperative changes after polydactyly.

Adolescent↗
PubMed1996

Complete palmar dislocation of the lunate in rheumatoid arthritis. Avascularity without avascular changes.

We report a case of complete palmar dislocation of the lunate in a rheumatoid patient. X-rays showed a normal bone structure of the lunate without sclerosis or collapse and on MRI an almost normal signal intensity was found. The lunate was removed. Histological examination showed complete necrosis of both marrow and bone cells, and tetracycline labelling showed no fluorescence. This case illustrates that neither X-ray nor magnetic resonance imaging (MRI) can detect complete bone necrosis. When X-ray or MRI changes do occur, these are indications of cellular events following some degree of spontaneous revascularization.

Aged↗
PubMed1996

Injectable calcium phosphate in the treatment of distal radial fractures.

An injectable material which hardened in situ to form a carbonated hydroxyapatite, Norian SRS (Norian Corp., Cupertino, USA), was used as the only treatment of unstable distal radial fractures in six patients. Except for an external dorsal splint for 2 weeks, no other treatment was used. The material maintained reduction except in one case in which there were technical problems during hardening and the material fragmented postoperatively. By 1 year all patients had a satisfactory clinical outcome. There was an early return of motion. The possibility of mobilization 1 or 2 weeks after the operation may reduce postoperative stiffness and increase short-term functional outcome.

Apatites↗
PubMed1996

The Porous-Coated Anatomic total knee experience. Special emphasis on complications and wear.

One hundred sixty knees in 141 patients with the Primary Porous-Coated Anatomic prosthesis (Howmedica, Rutherford, NJ) were evaluated after a follow-up period of 5.6 years (range, 1-10 years). One hundred six knees were in the latest follow-up evaluation, including clinical examination and a defined standing radiograph with a follow-up period of 6.3 years (range, 3-10 years). Survivorship analysis regarding the cumulative revision rate (including completion with a patellar component) was 0.88 at the 8-year and 0.84 at the 10-year follow-up examination. The clinical result was satisfying/good, with a mean Hospital for Special Surgery score of 83 (range, 39-97). Five percent had thinning greater than 30% of the tibial component. The wear was calculated to be 1.0 mm (range, 0-9 mm), including three revised tibial components with heavy wear. Excluding the revised cases, the wear was 0.7 mm.

Aged↗
PubMed1996

Chromosome rearrangements in synovial chondromatous lesions.

Short-term cultures from one synovial chondroma and three cases of synovial chondromatosis, a lesion for which no previous karyotypic information exists, were cytogenetically analysed. Whereas the chondroma displayed the relatively simple karyotype 46,XY,add(12)(q13),der(17)t(12;17)(q13;q21), more complex changes were found in the three cases of chondromatosis: case 1, 47,XY,der(1)inv(1)(p13q25)del (1)(q25q32), t(1;12)(q25;q13), + 5,der(12)add(12)(p11)t(1;12)(p22;q13); case 2, 47,XY,add(10)(q26), + 20/46 idem,-6/46,XY,t(2;4)(q33;q21), add(21)(p11); and case 3, 44,XY,add(1)(p36), del(1)(p13p22),add(6)(p25), del(7) (q22q32),del(10)(q21),add(11)(q13),-17,-18. The cytogenetic findings strongly suggest that synovial chondro-matosis is a clonal proliferation. Apart from a near-diploid chromosome number, the only recurrent cytogenetic features among the four cases were loss of band 10q26 and rearrangements of 1p13 and 12q13, found in two cases each. While chromosome bands 1p13 and 10q26 have not been reported to be involved in other types of benign chondromatous lesions, the 12q13-15 segment is recurrently rearranged in a variety of chondromatous tumours, e.g. pulmonary chondroid hamartomas. The present finding of translocations affecting band 12q13 in two of the cases emphasises that, irrespective of the anatomical localisation of the tumours, rearrangements of genes in 12q13-15 are important in the development of a large subset of benign and malignant cartilage-forming tumours.

Aged↗
PubMed1996

Development of radiographic damage during the first 5-6 yr of rheumatoid arthritis. A prospective follow-up study of a Swedish cohort.

The objective of this study was to describe the development of radiographic damage in patients with RA and to search for predictors of radiographic progression over 5 yr. One hundred and thirteen patients, 75 female and 38 male, mean age 53 yr, with definite RA and mean disease duration of 11.4 months, were followed prospectively for 5 yr at an out-patient clinic. Radiographs of the hands and feet were performed annually, and evaluated according to Larsen. The predictive value of demographic, clinical and laboratory variables at study start was evaluated. A stepwise logistic regression model was applied. We found that radiological joint damage occurred early and was significantly progressive during the 5 study years. The rate of progression was most prominent during the first 2 yr. At study start, 53% of the patients had no detectable erosions, but only 11% remained non-erosive. Twenty-six per cent of the patients with the initial presence of erosions did not progress substantially and needed no aggressive therapy. High joint damage progression during the first year, female gender and high baseline ESR could predict 57% of the patients with high total radiographic progression. Age, disease duration, rheumatoid factor, genetic factors, active joint count and the presence of erosions at study start had no predictive value.

Antirheumatic Agents↗
PubMed1996

Radiation dose reduction in computed skeletal radiography. Effect on image quality.

PURPOSE: To evaluate the effect of radiation dose reduction on image ++quality in computed musculoskeletal radiography and determine optimal exposure range. MATERIAL AND METHODS: In 11 corpses, 1 hand and 1 hip were examined with film-screen radiography, and a series of computed radiographs was obtained using exactly the same technique except for the exposure, which was 100, 50, 25, 12.5, 6.25, and 1.56% of the mAs numbers used for the film-screen images. The computed hip radiographs were processed in 2 different ways, one simulating the film-screen images and one using contrast enhancement. Four radiologists reviewed the images regarding the following parameters: cortical bone, trabecular bone, joint space, and soft tissue, giving each a diagnostic quality rating on a scale from 1 to 5. The median and mean values were found for the pooled results. RESULTS: For the hands, the computed radiographs were ranked inferior to the film-screen images for all parameters except soft tissue, where the computed radiographs scored higher. The computed images with 50 and 25% exposure were ranked equal to the 100% ones. The quality rating slowly declined with lower exposures. For the hips, the 100 and 50% computed radiographs were generally similar to or slightly better than the film-screen images. The decline was somewhat faster than for the hands. The contrast-enhanced hip images scored less than the nonenhanced images at any given exposure for all parameters except soft tissue, where the contrast-enhanced images scored better at all exposures. The difference between nonenhanced and enhanced images became less at the lower exposures. CONCLUSION: Lowering the exposure in computed musculoskeletal radioagrphy below the level of film-screen radiography is feasible, especially in the peripheral skeleton. Contrast enhancement seems to be valuable only in the evaluation of soft-tissue structures.

Bone and Bones↗
PubMed1996

Spatial resolution requirements in digital radiography of scaphoid fractures. An ROC analysis.

PURPOSE: To investigate the spatial resolution requirements in digital radiography of scaphoid fractures. MATERIAL AND METHODS: Included in the study were 60 scaphoid radiographs with and 60 without fractures of the scaphoid bone. The film-screen images were digitized using pixel sizes of 115, 170, and 340 microns along with 170 microns with a 10:1 wavelet compression. The digital images were displayed on a 1280 x 1024 x 8 bits monitor, and 5 observers evaluated the images in 5 randomized sessions. The results for each pixel size were then compared to the film-screen images by ROC analysis. RESULTS: The mean area under the ROC curves was larger for the film-screen images than for the digital images at all resolutions. However, this difference was not significant when the areas under the ROC curves for the film-screen images were compared to the digital images of 115, 170, and 170 microns with 10:1 compression. There was a significant difference for the 340-microns pixel size in favour of the film-screen images. The mean ROC curves for the digital images were very similar for the 115 and 170 microns pixel sizes, although slightly better for 115 microns. At 170 microns, the compression seemed to have a relatively small negative effect on the diagnostic performance; the deterioration was greater when the pixel size was increased to 340 microns. There was no obvious correlation between diagnostic performance and the experience of the observers in using work-stations. CONCLUSIONS: The pixel size of 170 microns is adequate for the detection of subtle fractures, even after wavelet compression by a ratio of 10:1.

Angiography, Digital Subtraction↗
PubMed1996

Angular configuration of the knee. Comparison of conventional measurements and the QUESTOR Precision Radiography system.

PURPOSE: The aim of this study was to assess the QUESTOR Precision Radiography system (QPR) and to compare it with the routine hip-knee-ankle (HKA) angle measurements. The aim was also to evaluate the robustness of the QPR system against the osseous changes of arthrotic disease. MATERIAL AND METHODS: Twenty-four patients, operated on with a high tibial osteotomy for medial gonarthrosis, were examined. The alignment of the leg was measured by the conventional technique and by the QPR method. RESULTS AND CONCLUSION: The 2 methods correlated well. The intraobserver variation in the QPR measurements was, with the exception of the capito-midcondylar-femoral shaft angle and the tibial plateau width, not affected by the osseous changes inflicted by the arthrotic process. The patients tolerated both systems well while the staff preferred the QPR system.

Ankle↗
PubMed1996

Gadolinium-DTPA-enhanced MR imaging in asymptomatic knees.

PURPOSE: To evaluate the occurrence and extent of Gd-DTPA-enhanced synovial structures in asymptomatic knee joints of middle-aged healthy individuals. MATERIAL AND METHODS: MR imaging of the knee joint was performed in 10 healthy subjects aged 40-61 years. The study included a sagittal T1-weighted SE sequence before and after i.v. injection of 0.1 mmol Gd-DTPA/kg b.w. RESULTS: Contrast-enhanced synovial structures were found in all knees. The extent of the synovial structures was usually not uniform within the examined joint. In the intercondylar fossa, the thickness of synovial structures was more often pronounced. In the suprapatellar recess, synovial thickness was constant and minimal. CONCLUSION: The presence and the varying extent and thickness of synovial structures in asymptomatic knees in middle-aged individuals must be considered in the evaluation of early and mild synovitis of the knee joint with Gd-enhanced MR imaging in this age group.

Adult↗
PubMed1996

Focal destruction and remodeling in guinea pig arthrosis.

We investigated the proximal tibiae in adult, middle-aged and old (6,12, and 30 months) guinea pigs with spontaneous arthrosis by quantitative morphometry. Since the cartilage destruction develops predominantly in the medial tibial plateau, the lateral side may serve as an internal control, In established lesions, cartilage destructions were focal, surrounded by a brim of thickened cartilage that was grossly intact, but showed cell clustering, hypertrophy and increased metachromasia. Peripherally, there was a distinct transition to normal-appearing cartilage. Subjacent to the cartilage ulcerations, subchondral bone was thickened. Compared to the lateral plateau the height of the calcified cartilage increased and the surface density of the osteocartilaginous interface decreased. Marrow depletion and cysts developed below the cartilage ulcerations. Cysts seem to develop through fibrous tissue partially undergoing cartilage metaplasia in tiny noduli that subsequently coalesce, liquefy centrally and expand. Superficially, similar fibrocartilaginous proliferations result in incomplete resurfacing and small areas of subchondral resorption; in the periphery of the joint, they form osteophytes. In the guinea pig, arthrosis tissue destruction is thus accompanied by local tissue proliferation.

Animals↗
PubMed1995

Short-term complications of the lateral approach for non-constrained elbow replacement. Follow-up of 50 rheumatoid elbows.

We reviewed 50 capitellocondylar elbow replacements performed by the lateral approach in 42 rheumatoid patients, at a median follow-up of three years. There were two major and 17 minor complications; 18 were early and one was late. Eight elbows required reoperation: soft-tissue surgery was performed in seven and prosthesis removal in one because of a deep infection. There were few problems of instability, but one patient sustained a traumatic dislocation which was stabilised after ligament reconstruction. Wound healing was delayed in two of five elbows which had been immobilised postoperatively for only five days, but healing was rapid in 45 elbows immobilised for 12 days. There was transient ulnar-nerve palsy postoperatively in 11 patients, with permanent palsy in three. All elbows were painfree or only slightly painful at follow-up; 49 were stable and 43 had a range of motion sufficient for activities of daily living. Radiological loosening of the humeral component was suspected in one asymptomatic elbow. The lateral approach is recommended for use with the capitellocondylar type of prosthesis in rheumatoid elbows with reasonably well-preserved bone stock.

Activities of Daily Living↗
PubMed1995

Computed radiography in scoliosis. Diagnostic information and radiation dose.

The diagnostic information and radiation dose in scoliosis examinations performed with air-gap technique using stimulable phosphor imaging plates were determined in a prospective study. Overlapping p.a. images of the thoracic and lumbar spine in 9 patients were obtained with 4 different exposure settings according to patient size. Equal exposure settings were used for the 2 images. Two images of 18 were judged inferior in depicting the landmarks of scoliosis measurement, requiring re-exposure. Sixteen images were judged of adequate or good quality. The mean entrance doses in the central beam for the 4 patient groups were in the interval of 0.05 to 0.12 mGy for both images. The skin doses on the breasts were in the range of 0.00 to 0.03 mGy. The presented technique thus results in a low radiation dose with sufficient diagnostic information in radiography of scoliosis.

Adolescent↗
PubMed1995

Computed vs. film-screen magnification radiography of fingers in hyperparathyroidism. An ROC analysis.

One hundred randomly selected patients with suspected or known hyperparathyroidism were examined in a prospective study of the 2nd and 3rd fingers with film-screen and digital luminescence radiographs using magnification technique. The digital images were displayed on a work-station and printed as hard-copies. Two radiologists evaluated the film-screen images regarding subperiosteal and intracortical resorption and their results were defined as "gold standard" regarding the absence or presence of these changes. Four radiologists evaluated these changes in the 3 image forms and an ROC analysis was performed. Comparing the areas under the ROC curves no significant difference was found between the film-screen images and the 2 digital display forms. These results suggest that currently available digital systems provide adequate diagnostic accuracy for evaluation of subtle skeletal changes.

Adolescent↗
PubMed1994

Loss of chromosome band 8q24 in sporadic osteocartilaginous exostoses.

We have karyotyped eight sporadic osteocartilaginous exostoses (OCE), a tumor type not characterized cytogenetically before. Five tumors had only normal karyotypes, whereas three displayed the following abnormal karyotypes: 46,XY,del(8)(q24.1); 46,XX,del(8)(q22), t(8;14)(q24.1;q32); and 46,XY,der(8)t(1;8)(q21;q24),inv(12)(p11q13). All three aberrant cases thus had structural rearrangements leading to loss of the distal part of 8q. This is of particular interest because multiple OCE are part of the disease phenotype in patients with the autosomal dominant tricho-rhino-phalangeal syndrome type II (TRP II), many of whom have constitutional loss of genetic material from 8q24.1. We hypothesis that band 8q24.1 harbors a tumor suppressor gene, the homozygous inactivation of which is important in the genesis of both inherited and sporadic OCE. In the familial form, i.e., in TRP II, loss or functional inactivation of one allele is inherited and only the second mutation is due to a somatic event, whereas both mutations are somatic in the sporadic forms. This hypothesis can be tested by analysis of sporadic and inherited OCE for homozygous loss of 8q24 material with molecular genetic techniques.

Adolescent↗
PubMed1994

Experimental osteonecrosis of the lunate. Revascularization may cause collapse.

Is lunate collapse in Kienböck's disease a consequence of spontaneous revascularization, leading to focal osteolysis? A literature review of osteonecrosis in other locations such as the femoral head and bone allografts showed clearly that the loss of mechanical integrity is due to cellular processes which follow the spontaneous restoration of blood supply. We found no evidence in the literature that the lunate has been shown to be avascular at the time of collapse. On the contrary, increased osteoclastic activity has been reported. We excised and reimplanted the lunate in two monkeys, and found spontaneous revascularization, leading to increased osteoblastic activity. Other parts of the bone were destroyed by osteoclasts, leading to collapse. This histological example suggests that it may be possible to make an analogy with osteonecrosis in other locations. Thus, changes on plain radiography may indicate that the bone is revascularized spontaneously. Before performing operative revascularization of the lunate, one should consider that revascularization is a probable cause for collapse.

Animals↗
PubMed1994

Os centrale carpi simulating a scaphoid waist fracture.

The os centrale carpi is a relatively rare accessory carpal bone, and its presence may be confused with a scaphoid fracture. A case is presented which simulated an un-united scaphoid fracture on the plain X-ray film. However, CT in the sagittal plane showed two rounded fragments on the dorsum of the scaphoid with smooth, regular cortical margins differing from an acute scaphoid fracture. Their volume combined with the volume of the scaphoid is more than that of a completely normal scaphoid. There is no evidence of degeneration in the two rounded fragments and scaphoid. Because of these features, the diagnosis of soft tissue injury with an incidental finding of an os centrale carpi was suggested.

Aged↗