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Biomedical subjects

A S Carlsson

Publications and source records attributed to A S Carlsson.

At least 19 recordsLinked to original sources

Arthrodesis of the ankle secondary to replacement.

One hundred total ankle arthroplasties were performed in our department between 1974 and 1994, and of these, 21 have been reoperated on with arthrodesis due to septic or nonseptic failures after 6 months to 15 years (median 40 months). Immobilization using a Hoffman external fixator was the dominating method. The total ankles were of six different designs. Sixteen of the 21 patients suffered from rheumatoid arthritis. Four of the 21 ankles did not fuse whereas 17 did: 13 at the first attempt and 4 after repeat arthrodesis. At the time of the review, two patients had died. Of the remaining 15 patients whose ankles had fused, all but one were satisfied or somewhat satisfied with the result. Twelve of these 15 ankles rated excellent or good according to the Mazur and Kofoed scoring systems. We conclude that arthrodesis can be performed successfully after a failed ankle arthroplasty.

Adult↗

Wear in uncemented porous and cemented polyethylene sockets: a randomised, radiostereometric study.

We used radiostereometric analysis to compare wear rates between uncemented porous sockets and cemented all-polyethylene sockets in a series of 102 hips randomised for either a Harris-Galante or a Charnley cup. Wear was evaluated in 95 hips at a mean of five years (2 to 7). All hips had a cemented, 22 mm head mono-bloc Charnley stem. The mean annual wear rate was 0.09 mm in the Charnley sockets and 0.10 mm in the Harris-Galante sockets, with no statistically significant differences in wear, migration or rotation. We conclude that, up to five years, the wear characteristics of the modular and porous Harris-Galante socket resemble that of the Charnley socket.

Acetabulum↗

Hydroxyapatite augmentation of the porous coating improves fixation of tibial components. A randomised RSA study in 116 patients.

In a single-blind, randomised series of knee replacements in 116 patients, we used radiostereometric analysis (RSA) to measure micromotion in three types of tibial implant fixation for two years after knee replacement. We compared hydroxyapatite-augmented porous coating, porous coating, and cemented fixation of the same design of tibial component. At one to two years, porous-coated implants migrated at a statistically significantly higher rate than hydroxyapatite-augmented or cemented implants. There was no significant difference between hydroxyapatite-coated and cemented implants. We conclude that hydroxyapatite augmentation may offer a clinically relevant advantage over a simple porous coating for tibial component fixation, but is no better than cemented fixation.

Aged↗

Migration and wear of a hydroxyapatite-coated hip prosthesis. A controlled roentgen stereophotogrammetric study.

A consecutive series of 30 total hip replacements using a hydroxyapatite (HA)-coated, modular implant (Omnifit) was followed clinically and by roentgen stereophotogrammetric analysis for two years and compared with two control groups, one of 27 cemented Charnley sockets and one of 40 cemented Charnley stems. Omnifit sockets with a central gap between the dome of the socket and the acetabular bone in the postoperative radiographs, migrated less than sockets without such gaps (p = 0.01). After adjustment for patient-related factors (age, gender and weight), no significant difference was found between the two prostheses with respect to micromotion and wear. We conclude that the early fixation of the HA-coated Omnifit prosthesis compares with that of the cemented Charnley prosthesis.

Adult↗

A large collar increases neck resorption in total hip replacement. 204 hips evaluated during 5 years.

We evaluated the effect of a prosthetic collar on the proximal femoral bone in 204 hips without any signs of loosening after 5 years. The patients were operated on at 5 centers, using different prosthetic designs, but the same cementing technique. Resorption was more often found in cases with a true and large collar (Lubinus, HD2, Scanhip) than in cases with a flanged or tapered stem (Charnley, Exeter). The resorption was also more pronounced with the former designs. It was concluded that, in spite of theoretical advantages, a large collar is not only unnecessary but may also have negative long-term effects.

Analysis of Variance↗

Improved radiographic survival of the Charnley prosthesis in rheumatoid arthritis and osteoarthritis. Results of new versus old operative techniques in 402 hips.

Two hundred one consecutive, primary, noninfected Charnley (Thackray, Leeds) hip arthroplasties, implanted from 1968 to 1985 due to adult-onset rheumatoid arthritis, were matched in pairs with respect to year of operation, age, and sex with 201 Charnley prostheses implanted due to osteoarthritis. The 10-year survival estimate for nonrevisions was 95% in the rheumatoid group and 89% in the osteoarthritic group. Using definite radiographic loosening as a determinant, the 7-year survival rate for stems increased from 80% to 96% for both groups after the introduction of new cementing techniques, and the relative risk for stem loosening was decreased to one fifth. In the rheumatoid arthritis group, the 7-year radiographic socket survival increased from 87% to 96%, an increase ascribed to the overall effect of the introduction of flanged sockets, bone-grafts in acetabular protrusion, the rejection of the pilot hole technique, and improvements in the cement handling technique. In the osteoarthritis group the radiographic socket survival rate at 7 years was 97% and at 10 years was 95%.

Adult↗

Migration of acetabular components, inserted with and without cement, in one-stage bilateral hip arthroplasty. A controlled, randomized study using roentgenstereophotogrammetric analysis.

Twenty-one patients who had primary osteoarthrosis were managed with a bilateral total hip arthroplasty with insertion of a Charnley femoral component. In each patient, one hip was randomly allocated to have a Harris-Galante acetabular component inserted without cement, and the contralateral hip was treated with an all-polyethylene Charnley acetabular component fixed with cement. The clinical result was satisfactory in all patients. All forty-two hips were followed, with respect to migration of the acetabular component, with use of roentgenstereophotogrammetric analysis for a median of twenty-seven months (range, twenty-three to forty-nine months). Each patient served as his or her own control. Maximum migration in any direction was 1.7 and 2.1 millimeters, and maximum rotation was 2.2 and 2.0 degrees for the Harris-Galante and Charnley acetabular components, respectively. There was no significant difference in migration between the two designs of acetabular components (p = 0.98, p = 0.75, and p = 0.06 for the transverse, longitudinal, and sagittal axes, respectively). However, the Harris-Galante acetabular components rotated significantly more than the Charnley acetabular components around two of the three axes (p = 0.008, p = 0.08, and p = 0.03 for the transverse, longitudinal, and sagittal axes, respectively). The Charnley hip implant has been used clinically for a long time, with successful results. Comparison of new designs of implants with the Charnley prosthesis is therefore important. Roentgenstereophotogrammetric analysis provides a potential for detection of problems with fixation at an early stage rather than after long-term follow-up. No major difference in terms of skeletal fixation was found between the two designs of components after short to medium-term follow-up.

Acetabulum↗

Cemented versus uncemented socket in hip arthroplasty. A radiostereometric study of 60 randomized hips followed for 2 years.

60 patients with arthrosis who received a Charnley total hip replacement were randomly assigned to either an uncemented porous Harris-Galante type I socket or a cemented all-polyethylene Charnley socket. Socket migration and rotation were studied by radiostereometry (RSA) for 2 years. After 2 years, all sockets were still in situ. There was no difference in migration or rotation between the 2 socket designs, nor was there any difference in pain or function. We conclude that the initial fixation of the Harris-Galante socket resembles that of the Charnley socket.

Adult↗

Early radiographic loosening impairs the function of a total hip replacement. The Nottingham Health Profile of 49 patients at five years.

We made a study of 49 total hip arthroplasties at five years, comparing the Charnley hip score, the Nottingham Health Profile (NHP) score and the appearance on serial radiographs. Each of the three investigations was performed by an independent observer with no knowledge of the results of the other two studies. The eight patients with radiographic signs of prosthetic loosening had significant reductions in function and quality of life as measured by the NHP questionnaire, but no differences in the mean Charnley hip scores. None of the eight patients had clinical signs of prosthetic loosening sufficient to recommend revision of their THR. The NHP is a relatively low-cost method of providing long-term follow-up of THR.

Activities of Daily Living↗

Low- vs high-viscosity cement in hip arthroplasty. No radiographic difference in 226 arthrosis cases followed for 5 years.

In 1984 and 1985, 352 hips were randomly assigned to total hip arthroplasty with either low- or high-viscosity cement at 5 Swedish orthopedic departments. Of the 267 hips finally included in the study, 226 were examined clinically and radiographically after 54-77 months. Radiographically, 21 definite stem loosenings and 1 probable stem loosening were observed (10 percent) and 4 additional stems had been exchanged before the 5-year examination. In the survivorship analysis, 261 stem prostheses were included and using this method, 7 percent were radiographically loose after 5 years. There were 4 definitely loose and 8 probably loose acetabular cups. No difference was found between cement of high and low viscosity with regard to prosthetic fixation.

Aged↗

Air contamination during total hip arthroplasty in an ultraclean air enclosure using different types of staff clothing.

Air contamination was measured in a down-flow, clean air enclosure during 50 total hip arthroplasties to compare the effect of different scrub suits and operating gowns. In one series, with cotton clothes, the operating gowns used were either disposable nonwoven operating gowns or total body exhaust gowns. With the exhaust gowns the median air contamination, measured as colony-forming units (cfu)/m3, was reduced by about 5 times, to 0.3. In another series, nonwoven operating gowns were used together with scrub suits made of either cotton or one of two types of synthetic materials. The latter two scrub suits were equipped with elastic sealings at the openings. With both of these types the median air contamination, compared to cotton scrub suits, was reduced by about one half, to 0.4 cfu/m3. The authors conclude that both specially designed scrub suits and exhaust gowns can further reduce an already low level of bacterial air contamination in a down-flow, clean air enclosure.

Air Microbiology↗

The diagnostic value of C-reactive protein in infected total hip arthroplasties.

In 50 patients with non-infected total hip arthroplasties (THA), 233 C-reactive protein (CRP) values were obtained over a three-year period. Six of these 50 patients occasionally had CRP values of over 20 mg/l. The erythrocyte sedimentation rate (ESR) and CRP concentration were measured in 23 patients with deep infections of THA before revision. In 11 patients the infections were caused by coagulase-negative staphylococci. CRP exceeded 20 mg/l in 18 patients and the ESR was more than 30 mm/hr in 14. In only one infected patient were both CRP and ESR below these levels. All of 33 patients with non-septic loosening had CRP less than 20 mg/l and ESR less than 30 mm/hr before revision. C-reactive protein seems to be a valuable supplement to the ESR in the monitoring of infection after THA.

Adult↗

Occlusive clothing and ultraviolet radiation in hip surgery.

In a randomized study of 20 total hip arthroplasties, the staff wore shirts and trousers of a fabric impervious to bacteria underneath operating gowns of a non-woven material. Volumetric air sampling demonstrated a low number of colony-forming units with this clothing, further reduced by ultraviolet radiation to below 10 colony-forming units/m3, the upper limit of "ultraclean air," in all the cases (median 2.6, range 1.1-7.1).

Air Microbiology↗

Loosening of the socket in a 35-mm snap-fit prosthesis and the Charnley hip prosthesis. A roentgenographic evaluation of 321 cases operated upon because of osteoarthritis.

Migration and lucencies around the acetabular component were evaluated in serial roentgenograms of patients with osteoarthritis treated with total hip arthroplasty (THA); 207 were Charnley and 114 were Brunswik THAs. In this consecutive series of THAs followed for nine to ten years, the loosening rate (corrected for deaths and revisions) was significantly higher (35%-45%) in the Brunswik snap-fit sockets (bearing surface 35 mm in diameter) than in the Charnley sockets (5%-12%). Presumably, mechanical factors, i.e., friction torque and impingement, are responsible for the difference in durability between the two designs.

Aged↗

Revision operations on infected total hip arthroplasties. Two- to nine-year follow-up study.

One hundred two of 110 infected hip arthroplasties revised with the protection of gentamicin-loaded cement were followed for a minimum of two years. In 77 of 102 hips the infection healed after one revision operation and in five of eight hips after a second revision operation, representing a final healing rate of 80%. No significant difference in healing rate could be demonstrated with regard to individual bacterial species. However, in infections with a mixed flora, the healing rate was only 27% (p less than .01). After an average of six years, 33 of 82 healed hips had signs of roentgenographic loosening, nine of which had been revised. The modified Merle d'Aubigne and Postel score averaged 5.3 for pain, 3.7 for walking ability, and 4.0 for range of motion (ROM) in patients with healed infections.

Adult↗