| 1. |
- Kesteris, U, et al.
(författare)
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Cumulative revision rate with the Scan Hip Classic I total hip prosthesis. 1,660 cases followed for 2-12 years
- 1998
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 69:2, s. 133-137
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed the cumulative revision rate in 1,474 patients (1,660 hips) operated on with a cemented Scan Hip Classic I prosthesis from November 1983 to January 1994 at Lund University Hospital. The revision rate was analyzed for 3 diagnoses--arthrosis, rheumatoid arthritis and complication after a hip fracture--and for 2 head diameters--22 and 32 mm. Until January 1996, 36 hips were revised: 31 because of aseptic loosening, 3 because of dislocation and 2 because of infection. The overall revision rate was 5.6% after 10 years and was similar in arthrosis, rheumatoid arthritis and fracture cases. Due to revisions because of dislocation in the 22 mm group, the total revision rate was lower in the 32 mm group (p = 0.03).
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| 2. |
- Kesteris, Uldis, et al.
(författare)
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Polyethylene wear and synovitis in total hip arthroplasty: a sonographic study of 48 hips
- 1999
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Ingår i: Journal of Arthroplasty. - 0883-5403. ; 14:2, s. 138-143
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Tidskriftsartikel (refereegranskat)abstract
- Forty-six patients (48 hips), operated on with cemented total hip arthroplasty (THA) because of arthrosis, were examined radiographically and sonographically at 10-year follow-up. Polyethylene wear of acetabular cups was measured on conventional non-weight-bearing pelvic radiographs, and the volume of polyethylene debris was calculated. Radiographic signs of loosening were identified. The capsular distance (ie, thickness of the synovium or synovial contents) was measured sonographically. We found a significant correlation between increased volumetric wear and increased capsular distance. Hips with radiographically loose acetabular components had significantly greater volumetric wear and capsular distance than those without signs of acetabular loosening. This relationship was not observed in hips with radiographically loose femoral components. In cemented THA, the volume of polyethylene wear debris and the thickness of the synovium and the synovial contents are related. In the event of radiographic loosening of the acetabular component, they are both increased.
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| 3. |
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| 4. |
- Lewold, Stefan, et al.
(författare)
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Oxford meniscal bearing knee versus the Marmor knee in unicompartmental arthroplasty for arthrosis. A Swedish multicenter survival study
- 1995
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Ingår i: Journal of Arthroplasty. - 0883-5403. ; 10:6, s. 722-731
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Tidskriftsartikel (refereegranskat)abstract
- In the Swedish Knee Arthroplasty Study, all 699 Oxford meniscal bearing cemented unicompartmental prostheses (Biomet, Bridgend, UK) were identified and analyzed regarding failure pattern and compared with all Marmor prostheses (Smith & Nephew Richards, Orthez, France) and with a time-, age-, and sex-matched subset of Marmor prostheses using survival statistics expressed as cumulative revision rates. After 1 year there was already a higher rate, and after 6 years the rate of the Oxford group was more than twice that of the Marmor group. There were 50 revisions in the Oxford group: dislocating meniscus in 16, loosening of the femoral component in 6, tibial component in 4, both components in 4, contralateral arthrosis in 10, infection in 4, and technical failure with instability, pain, and/or impingement of the meniscal bearing anterior in the femoral condyle in 6. It is still unclear if the design with the sliding menisci will, in the long turn, reduce wear and loosening, thereby compensating for the initially inferior results. It is recommended that until this question is clarified, the Oxford knee should be used on a limited scale for long-term comparative studies only.
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| 5. |
- Lewold, Stefan, et al.
(författare)
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Revision of unicompartmental knee arthroplasty: outcome in 1,135 cases from the Swedish Knee Arthroplasty study
- 1998
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 69:5, s. 469-474
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Tidskriftsartikel (refereegranskat)abstract
- From 1975 through 1995, 45,025 knee arthroplasties were recorded in the prospective Swedish Knee Arthroplasty study. By the end of 1995, 1,135 of 14,772 primary unicompartmental knee arthroplasties (UKA) for localized, mainly medial arthrosis had been revised. The Marmor/Richards and St. Georg sledge/Endo-Link prostheses were used in 65%. Mean age at revision was 72 (71) years. 232 revisions were performed as an exchange UKA (partial in 97) and 750 as a total knee arthroplasty (TKA). 153 were revised by other modes. In medial UKA, the indication for revision was component loosening in 45% and joint degeneration in 25% and in lateral UKA, the corresponding figures were 31% and 35%, respectively. In 94 cases, unicompartmental components were added to the initially untreated compartment, in 14 with partial exchange of a component. The CRRR was estimated using survival statistics. After only 5 years, the risk of having a second revision was more than three times higher for failed UKAs revised to a new UKA (cumulative rerevision rate (CRRR 26%) than for those revised to a TKA (CRRR 7%). This difference remained, even if those revised before 1985, when modern operating technique was introduced, were excluded (CRRR 31% and 5%, respectively). UKA is a safe primary procedure, when performed with well-designed components and modern surgical technique. It gives documented good patient satisfaction, range of motion, pain relief and relatively few serious complications. However, once failed, the knee should be revised to a TKA. This applies to most modes of failure. Not even joint degeneration of the unoperated compartment can be safely treated by adding contralateral components; CRRR after this procedure was 17%, while it was 7% when converted to a TKA.
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| 6. |
- Robertsson, Otto, et al.
(författare)
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Intracapsular pressure and loosening of hip prostheses. Preoperative measurements in 18 hips
- 1997
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 68:3, s. 231-234
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Tidskriftsartikel (refereegranskat)abstract
- We measured the intracapsular pressure preoperatively in 18 hips (17 patients) before revision of a total hip arthroplasty because of aseptic loosening. Distension of the joint capsule was measured with sonography in 13 cases. In extension, the mean intracapsular pressure was 26 (0-60) mmHg, in extension and inward rotation it was 159 (24-280) mmHg, in extension and outward rotation it was 30 (3-67) mmHg and in 45 degrees of flexion it was 12 (0-28) mmHg. A mean of 6 (0.5-20) mL of joint fluid was aspirated after the pressure measurements. Sonography showed increased joint fluid/synovial edema and/or increased capsular thickness, as compared to 34 unrevised, radiographically not loose prosthetic hips, and that the capsular distension correlated to intracapsular pressure during extension and inward rotation. We conclude that the intracapsular pressure usually is elevated in a hip joint with loose prosthetic components, that the intracapsular pressure varies with the position of the hip and that capsular distension reflects increased intracapsular pressure. The increased and often very high pressure, varying during gait, may pump debris away from the joint along the interfaces and even by itself cause osteolysis and loosening.
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| 7. |
- Robertsson, Otto, et al.
(författare)
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Intracapsular pressure and pain in coxarthrosis
- 1995
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Ingår i: Journal of Arthroplasty. - 0883-5403. ; 10:5, s. 632-635
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Tidskriftsartikel (refereegranskat)abstract
- Intracapsular hip pressure was measured before surgery in 17 patients (18 hips) with coxarthrosis. The results were correlated to pain as registered on a visual analog scale. With the hip in extension, the pressure was 49.5 mmHg (SD, 40.2); in 45 degrees of flexion, it was 21.3 mmHg (SD, 14.6); in extension and inward rotation, it was 105.7 mmHg (SD, 76.0); and in extension and outward rotation, it was 40.8 mmHg (SD, 32.0). A small amount, 0.7 mL (SD, 1.14), of joint fluid was aspirated following pressure registration. Pressure correlated significantly to pain at night, when starting to walk, and on walking. It is suggested that the increase in intracapsular hip pressure is a cause of pain in coxarthrosis, with subsequent limitation of movement and joint contracture.
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| 8. |
- Robertsson, Otto, et al.
(författare)
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Knee arthroplasty in rheumatoid arthritis. A report from the Swedish Knee Arthroplasty Register on 4,381 primary operations 1985-1995
- 1997
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Ingår i: Acta Orthopaedica Scandinavica. - 0001-6470. ; 68:6, s. 545-554
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Knee Arthroplasty Register has data on 4,381 primary operations performed 1985-1995 for rheumatoid arthritis. Of these, 192 were performed with unicompartmental prostheses and 4143 with tricompartmental. 77% were women and the mean age was 66 years. There were 126 first, 20 second, and 1 third revision in tricompartmental arthroplasties, mainly for loosening, infection and patellar problems. There were 38 first, 3 second, and 1 third revision in unicompartmental arthroplasties, mainly for progression of RA and loosening. Cumulative revision rates (Kaplan-Meier) were calculated. Tricompartmental knees had a 10-year cumulative revision rate of 5% and uni-knees 25%. Patients treated before 1990, men and patients younger than 55 had higher revision rates than patients treated after 1990, women and older patients, respectively. Cemented tibial components resulted in lower revision rates than uncemented ones. There was no significant difference in revision rates between patellar replaced and unreplaced knees or between the 9 commonest implant types.
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| 9. |
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| 10. |
- Robertsson, Otto, et al.
(författare)
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Use of unicompartmental instead of tricompartmental prostheses for unicompartmental arthrosis in the knee is a cost-effective alternative. 15,437 primary tricompartmental prostheses were compared with 10,624 primary medial or lateral unicompartmental prostheses
- 1999
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Ingår i: Acta Orthopaedica Scandinavica. - 0001-6470. ; 70:2, s. 170-175
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Tidskriftsartikel (refereegranskat)abstract
- Unicompartmental knee arthroplasty (UKA) is known to have a higher risk of revision than tricompartmental arthroplasty (TKA), while UKA implants are generally less expensive than TKA implants. We estimated the costs of implants and hospital stay of both procedures and related the cost difference at primary operation to the difference in number of revisions to be expected. We compared 15,437 primary TKAs and 10,624 primary medial or lateral UKAs. The operations were all done on patients with arthrosis during 1985-1995. By matching patients in the Swedish Patient Administration System with the Swedish National Knee Arthroplasty Register, the groups could be compared regarding the length of the hospital stay. The cumulative revision rate (CRR) and the relative risk of revision were calculated with survival statistics, as well as the risk of a second revision and the risk of infection. The weighted mean cost of the commonest implants in each group was used as an estimate of the implant cost. We found that the TKA patients were, on average, 2 years older at operation and had a lower CRR than the UKA patients-i.e., 10-year CRR of 12% and 16%, respectively. After adjusting for age, gender and year of operation, UKA patients were found to have a 2-day shorter hospital stay and fewer serious complications than TKA patients. The mean estimated cost of a unicompartmental implant was 57% of that of a tricompartmental implant. We conclude, that by using UKA instead of TKA in appropriate patients, money can be saved, even after taking into account the increased number of revisions to be expected.
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