1.
Önsten, Ingemar, et al.
(författare)
Migration of the Charnley stem in rheumatoid arthritis and osteoarthritis. A roentgen stereophotogrammetric study
1995
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 77-B:1, s. 18-22
Tidskriftsartikel (refereegranskat) abstract
Migration of 65 Charnley stems implanted with modern cementing techniques was studied by roentgen stereophotogrammetry. There were 25 patients with rheumatoid arthritis (RA) and 40 with osteoarthritis (OA) followed up for two years. In 43 cases a bone sample for histomorphometric analysis was obtained from the femur during the operation. In 22 cases the mean subsidence of the prosthetic head was 0.40 mm and in 20 the mean posterior migration was 1.25 mm. There was no difference in migration between the two diagnostic groups (p = 0.8) after adjusting for variations in gender, age and weight. Male gender was associated with increased subsidence (p = 0.006). Histological examination showed that the RA series had more osteoid surface (p = 0.04), but neither this, nor any of the other histomorphometric variables, influenced migration. These results suggest that, unlike the acetabular socket, the cemented Charnley femoral component is equally secure in osteoarthritis and in rheumatoid arthritis, and that its initial fixation is not influenced by the quality of the local cancellous bone. Our results provide data with which the early performance of new prosthetic designs and fixation methods can be compared.
2.
Önsten, Ingemar, et al.
(författare)
Hydroxyapatite augmentation of the porous coating improves fixation of tibial components. A randomised RSA study in 116 patients
1998
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 80-B:3, s. 417-425
Tidskriftsartikel (refereegranskat) abstract
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.
3.
Önsten, Ingemar, et al.
(författare)
Migration and wear of a hydroxyapatite-coated hip prosthesis. A controlled roentgen stereophotogrammetric study
1996
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 78:1, s. 85-91
Tidskriftsartikel (refereegranskat) abstract
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.
4.
Önsten, Ingemar, et al.
(författare)
Migration of uncemented, long-stem femoral components in revision hip arthroplasty. A 2-8 year clinical follow-up of 45 cases and radiostereometric analysis of 13 cases
1995
Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 66:3, s. 220-224
Tidskriftsartikel (refereegranskat) abstract
We reviewed after 48 (24-90) months the clinical results in 45 cases of revision hip arthroplasties where an uncemented, long-stem femoral prosthesis (BIAS, Zimmer) had been used. A subgroup of 13 cases was followed with radiostereometric analysis (RSA) for 2 years. 3/45 cases had been revised, another 12 had unsatisfactory pain scores. The median Harris score was 69 (26-99). 12/13 stems migrated; 11 subsided 4.1 (0.4-7.9) mm, and 8 migrated posteriorly 2.9 (1.9-9.6) mm. The poor clinical results and large migrations speak against the use of this prosthesis in revision hip arthroplasty.
5.
Önsten, Ingemar, et al.
(författare)
Wear in uncemented porous and cemented polyethylene sockets: a randomised, radiostereometric study
1998
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 80-B:2, s. 345-350
Tidskriftsartikel (refereegranskat) abstract
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.
