| 1. |
- Dahlberg, Leif, et al.
(författare)
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Proteoglycan fragments in joint fluid : Influence of arthrosis and inflammation
- 1992
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 0001-6470. ; 63:4, s. 417-423
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Tidskriftsartikel (refereegranskat)abstract
- We determined the concentration of proteoglycan fragments in knee joint fluid collected from knee-ligament injured patients more than 6 months after the trauma and from patients with acute pyrophosphate arthritis and arthrosis or with arthrosis only. Injured patients with normal or only mildly altered cartilage at arthroscopy and with normal radiographs, had twice the average concentration of healthy volunteers. Other injured patients with advanced, radiographic signs of arthrosis, had synovial fluid proteoglycan fragment concentrations within the range of healthy volunteers. Patients with pyrophosphate arthritis had the highest concentrations, substantially increased compared with both arthrosis patients, with or without knee injury and healthy volunteers. Likewise, there was an inverse relation between the degree of arthrosis and the concentration of proteoglycan fragments in the joint fluid in patients with pyrophosphate arthritis and arthrosis or with arthrosis only. We conclude that synovial fluid levels of proteoglycan fragments are influenced by the mass of cartilage matrix remaining in the joint, the inflammatory activity in the joint, and the metabolic activity of the cartilage cells.
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| 2. |
- Lohmander, Stefan, et al.
(författare)
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Increased levels of proteoglycan fragments in knee joint fluid after injury
- 1989
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 32:11, s. 1434-1442
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Tidskriftsartikel (refereegranskat)abstract
- We measured the levels of cartilage proteoglycan (PG) fragments in knee joint synovial fluid obtained from patients with previous trauma of the knee, early gonarthrosis, or pyrophosphate synovitis, and in age-matched control subjects. During the initial 3-4 weeks after rupture of the anterior cruciate ligament or the meniscus (confirmed by arthroscopy), markedly increased PG fragment levels were found. At later times after trauma (up to 4 years), many of these patients still had significantly elevated levels of cartilage PG fragments in the joint fluid. In a group of older patients with gonarthrosis, these levels were only moderately elevated, while in patients with acute pseudogout, greatly increased levels were observed. Although longitudinal studies are needed to validate the significance, PG fragments in joint fluid may be a marker for early posttraumatic arthrosis.
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| 3. |
- Almquist, Per Otto, et al.
(författare)
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Evaluation of an external device measuring knee joint rotation: an in vivo study with simultaneous Roentgen stereometric analysis.
- 2002
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Ingår i: Journal of Orthopaedic Research. - 1554-527X. ; 20:3, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- An external device ("rottometer") specially designed to measure knee joint rotation was developed and evaluated with respect to its validity. Simultaneous measurements were made with the rottometer and Roentgen stereometric analysis (RSA) in five patients with implanted tantalum markers in the tibia and femur. Measurements of internal and external rotation were made at 90 degrees and 60 degrees of knee flexion using 3, 6 and 9 N m torques. The coefficients of determination (r2) between the results obtained with the rottometer and RSA were around 0.9 for the total rotation. The rottometer consistently overestimated the rotation by about 100% and this systematic error was most constant at 90 degrees flexion for the different torques. The magnitude of this error from soft tissue deformation as well as the rotatory movements in the hip, foot and ankle joints must be considered when using external devices to measure knee rotation in clinical studies. The most accurate registrations were found in 90 degrees flexion with 9 N m force (r2 = 0.94).
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| 4. |
- Barker, D S, et al.
(författare)
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A circumferentially flanged tibial tray minimizes bone-tray shear micromotion.
- 2005
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Ingår i: Proceedings of the Institution of Mechanical Engineers. Part H: Journal of Engineering in Medicine. - 0954-4119. ; 219:6, s. 449-456
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Tidskriftsartikel (refereegranskat)abstract
- Aseptic loosening of the tibial component is the major complication of total knee arthroplasty There is an association between early excessive shear micromotion between the bone and the tray of the tibial component and late aseptic loosening. Using non-linear finite element analysis, whether a tibial tray with a circumferentially flanged rim and a mating cut in the proximal tibia could minimize bone-tray shear micromotion was considered. fifteen competing tray designs with various degrees of flange curvature were assessed with the aim of minimizing bone-tray shear micromotion. A trade-off was found between reducing micromotion and increasing peripheral cancellous bone stresses. It was found that, within the limitations of the study, there was a theoretical design that could virtually eliminate micromotion due to axial loads, with minimal bone removal and without the use of screws or pegs.
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| 5. |
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| 6. |
- Bernfort, Lars, et al.
(författare)
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Individualized metal implants for focal cartilage lesions in the knee can be cost-effective: A simulation on 47-year-old in a Swedish setting
- 2023
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Ingår i: JOURNAL OF ISAKOS JOINT DISORDERS & ORTHOPAEDIC SPORTS MEDICINE. - : ELSEVIER. - 2059-7754. ; 8:3, s. 197-203
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: In the aging population, the knee is the joint most commonly causing impaired function and incapacity. While definite treatment by prosthetic replacement is often performed late, symptomatic knee cartilage lesions cause much suffering also in younger ages. Early intervention could, therefore, be instituted at an early stage to the benefit of both patients and society. Small, metal surface, resurfacing implants have been tested with promising results. A system that features patient-specific implants and surgical instruments shows good clinical results and favorable survival rates. This study aims to assess the cost utility of this metal device compared with microfracture (MFX), being the standard procedure in Sweden. Methods: We constructed a simulation model in Excel. In the model, a cohort of 47-year-old patients (which is the mean age of patients treated with the metal implant) with symptomatic knee cartilage lesions received either MFX or metal implantation. Outcomes for the cohort were simulated over 40 years, such as in a previously published model based on MFX, and sensitivity analyses (deterministic and probabilistic) of the results were undertaken. Data on transition probabilities, costs, and quality of life were taken from clinical data, published literature, and official price lists. Only direct medical costs were included. Results: Results from the analysis showed that the metal device is a cost-effective treatment strategy compared with MFX. The incremental cost-effectiveness ratio (ICER) reached acceptable levels at similar to 5 years postoperatively. Over the full-time horizon of 40 years, the metal device was cost saving with concomitant gains in quality-adjusted life years (QALYs), translating to a dominant treatment strategy. Results were robust according to sensitivity analysis with the initial success rate of up to three years for both metal and MFX having the largest impact. Conclusions: A metal implant may be a cost-effective treatment alternative for patients in their 40s when compared to MFX in a Swedish setting.
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| 7. |
- Bottner, F, et al.
(författare)
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Implant migration after early weightbearing in cementless hip replacement
- 2005
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X .- 1528-1132. ; :436, s. 132-137
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-nine patients (five women and 24 men) with an average age of 47 years (range, 24-59 years) had 37 total hip arthroplasties using a hydroxyapatite-coated double-wedge press-fit femoral component. All patients had a Type A bone quality. Patients were either mobilized with weightbearing as tolerated or toe-touch weightbearing for 6 weeks postoperatively. After 6 weeks all patients were advanced to weightbearing as tolerated. Radiostereometric analysis radiographs were taken at 3 days, 6 weeks, and 6 months postoperatively to measure migration of the femoral component. Radiostereometric analysis revealed no difference in stem migration between the two groups as defined by maximal total point migration. There was a difference in the vertical (proximal-distal) migration within the first 6 weeks between groups (0.81 mm versus 0.13 mm), but not afterwards (0.17 mm versus 0.18 mm). Continuous migration after 6 weeks was observed in three patients from each group. There was no loosening in either group within a 2-year followup. Weightbearing as tolerated is recommended for young patients with excellent bone quality after cementless total hip arthroplasty with a double-wedge press-fit femoral component. Level of Evidence: Diagnostic study, Level I (testing of previously developed diagnostic criteria in series of consecutive patients-with previously applied reference gold standard). See the Guidelines for Authors for a complete description of levels of evidence.
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| 8. |
- de Boniface, J., et al.
(författare)
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The generalisability of randomised clinical trials: an interim external validity analysis of the ongoing SENOMAC trial in sentinel lymph node-positive breast cancer
- 2020
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Ingår i: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 180:1, s. 167-176
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Tidskriftsartikel (refereegranskat)abstract
- Purpose None of the key randomised trials on the omission of axillary lymph node dissection (ALND) in sentinel lymph-positive breast cancer have reported external validity, even though results indicate selection bias. Our aim was to assess the external validity of the ongoing randomised SENOMAC trial by comparing characteristics of Swedish SENOMAC trial participants with non-included eligible patients registered in the Swedish National Breast Cancer Register (NKBC). Methods In the ongoing non-inferiority European SENOMAC trial, clinically node-negative cT1-T3 breast cancer patients with up to two sentinel lymph node macrometastases are randomised to undergo completion ALND or not. Both breast-conserving surgery and mastectomy are eligible interventions. Data from NKBC were extracted for the years 2016 and 2017, and patient and tumour characteristics compared with Swedish trial participants from the same years. Results Overall, 306 NKBC cases from non-participating and 847 NKBC cases from participating sites (excluding SENOMAC participants) were compared with 463 SENOMAC trial participants. Patients belonging to the middle age groups (p = 0.015), with smaller tumours (p = 0.013) treated by breast-conserving therapy (50.3 versus 47.1 versus 65.2%, p < 0.001) and less nodal tumour burden (only 1 macrometastasis in 78.8 versus 79.9 versus 87.3%, p = 0.001) were over-represented in the trial population. Time trends indicated, however, that differences may be mitigated over time. Conclusions This interim external validity analysis specifically addresses selection mechanisms during an ongoing trial, potentially increasing generalisability by the time full accrual is reached. Similar validity checks should be an integral part of prospective clinical trials. Trial registration: NCT 02240472, retrospective registration date September 14, 2015 after trial initiation on January 31, 2015
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| 9. |
- Dunbar, M J, et al.
(författare)
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Appropriate questionnaires for knee arthroplasty. Results of a survey of 3600 patients from The Swedish Knee Arthroplasty Registry
- 2001
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Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 83:3, s. 339-344
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Knee Arthroplasty Registry (SKAR) has recorded knee arthroplasties prospectively in Sweden since 1975. The only outcome measure available to date has been revision status. While questionnaires on health outcome may function as more comprehensive endpoints, it is unclear which are the most appropriate. We tested various outcome questionnaires in order to determine which is the best for patients who have had knee arthroplasty as applied in a cross-sectional, discriminative, postal survey. Four general health questionnaires (NHP, SF-12, SF-36 and SIP) and three disease/site-specific questionnaires (Lequesne, Oxford-12, and WOMAC) were tested on 3600 patients randomly selected from the SKAR. Differences were found between questionnaires in response rate, time required for completion, the need for assistance, the efficiency of completion, the validity of the content and the reliability. The mean overall ranks for each questionnaire were generated. The SF-12 ranked the best for the general health, and the Oxford-12 for the disease/site-specific questionnaires. These two questionnaires could therefore be recommended as the most appropriate for use with a large knee arthroplasty database in a cross-sectional population.
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| 10. |
- Dunbar, Michael J, et al.
(författare)
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Translation and validation of the Oxford-12 item knee score for use in Sweden
- 2000
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 71:3, s. 268-274
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Tidskriftsartikel (refereegranskat)abstract
- The Oxford-12 Item Knee Score is a recently developed and validated patient-completed outcome measure designed specifically for use with knee arthroplasty in the United Kingdom. We have translated this questionnaire into Swedish and tested the validity and reliability of the translated version in a cross-sectional study by a postal survey to 1,200 randomly selected patients from the Swedish Knee Arthroplasty Register. Swedish versions of the WOMAC, Nottingham Health Profile, SF-36, SF-12, and the Sickness Impact Profile were employed in the validation process. We also tested feasibility and patient-burden parameters. The translated version appeared to be linguistically and culturally equivalent to the original version with good validity and reliability. Indirect measures of responsiveness indicated that it is at least as responsive to relevant knee arthroplasty patient states as the previously validated Swedish version of the WOMAC. Application of the translated questionnaire to this population is feasible with minimal imposed patient-burden. The Swedish translation of the Oxford-12 Item Knee Score is a valid and reliable tool for outcome studies on knee arthroplasty patients.
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| 11. |
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| 12. |
- Flivik, Gunnar, et al.
(författare)
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Effects of lamination on the strength of bone cement
- 1997
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Ingår i: Acta Orthopaedica Scandinavica. - : Medical Journals Sweden AB. - 0001-6470. ; 68:1, s. 55-58
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Tidskriftsartikel (refereegranskat)abstract
- To improve cement penetration into the cancellous bone of the acetabulum in hip arthroplasty, sequential cementation of each anchoring hole may be feasible. Since this procedure creates laminations in the cement, we have determined the conditions under which such laminations affect the strength of the cement. Cement bars made at 2, 3 or 4 minutes after the start of cement mixing and with either dry laminations or laminations including blood or saline were tested for tensile strength. Solid unlaminated bars were used as references. Dry and saline laminations made up to 4 minutes after the start of cement mixing did not reduce the strength of the cement. However, there was a time-dependent decrease in cement strength if blood was entrapped in the interface. In such cases, there was a decrease in strength for laminations made at 4 minutes, at 3 minutes this was less pronounced and at 2 minutes no weakening at all was noted. Our findings indicate that a sequential cementation procedure is permissible as regards cement strength, provided it is performed with 2-3 minutes after the start of cement mixing. If the cement area is kept free from blood, the time may be prolonged up to 4 minutes, without the risk of weakening the cement strength.
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| 13. |
- Flivik, Gunnar, et al.
(författare)
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Improved acetabular pressurization gives better cement penetration : In vivo measurements during total hip arthroplasty
- 2004
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Ingår i: The Journal of Arthroplasty. - : Elsevier BV. - 0883-5403 .- 1532-8406. ; 19:7, s. 911-918
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Tidskriftsartikel (refereegranskat)abstract
- During total hip arthroplasty, the intraoperative cementation pressure was measured inside one of the acetabular anchorage holes. Patients were randomized to pressurization of cement with either a conventional pressurizer or a sequential method including individual pressurization of each anchorage hole. The pressure was correlated to the cement penetration measured on digital radiographs. The early peak pressures were higher for the sequential method, resulting in a significantly better penetration of 2.8 mm compared with 0.7 mm with the conventional pressurizer. We found a strong correlation between early peak cementation pressures and cement penetration into the cancellous bone of the anchoring holes, indicating a cause-effect relationship at this early stage. The highest peak pressures were achieved during the later cup insertion, but these pressures did not correlate with the cement penetration. We conclude that conventional methods for cement pressurization in the acetabulum may not be optimal. © 2004 Elsevier Inc. All rights reserved.
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| 14. |
- Flivik, Gunnar, et al.
(författare)
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Is removal of subchondral bone plate advantageous in cemented cup fixation? A randomized RSA study.
- 2006
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Ingår i: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X. ; 448, s. 164-172
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Tidskriftsartikel (refereegranskat)abstract
- There is uncertainty regarding whether and how the subchondral bone plate should be treated during acetabular preparation for cemented cup fixation in a total hip arthroplasty. We hypothesized that removing the bone plate would improve the cement-bone interface without jeopardizing the initial cup stability, and therefore, be advantageous to long-term cup survival. We randomized 50 patients with primary osteoarthritis into two groups, one for removal and one for retention of the subchondral bone plate. The patients were evaluated during 2 years followup using repeated radiostereometric examinations, analyses of radiolucent lines, and clinical followups. Patient scoring was done using the Western Ontario and McMaster Universities Osteoarthritis Index, the Short Form-12, and the Harris hip score. Removal of the subchondral bone plate resulted in a superior cement-bone interface with less development of radiolucent lines. The radiostereometry results showed small migrations in both groups. We found no differences in cup stability between groups, although a difference was observed in rotational behavior with the removal group stabilizing in a slightly vertical position whereas the retention group showed slight but progressive rotation into a more horizontal position. No differences were found during clinical followups. Removing the subchondral bone plate, where possible, improves the cement-bone interface without jeopardizing the stability, implying better long-term cup survival. However, it is a more demanding surgical technique.
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| 15. |
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| 16. |
- Hansson, Ulrik, et al.
(författare)
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A randomised RSA study of Peri-Apatitetrade mark HA coating of a total knee prosthesis.
- 2008
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Ingår i: Knee. - : Elsevier BV. - 1873-5800. ; 15, s. 211-216
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In total knee replacement, sound early fixation of the prosthesis is crucial for achieving a good long-term result and for minimising the risk of loosening. Various types of prosthetic material, different surface textures and shapes and the incorporation of screws or pegs have been used to achieve good fixation, particularly in the uncemented knee. Hydroxyapatite (HA) coating of prosthetic joint components is another technique used to enhance early stability and so to improve the longevity of the prosthesis-bone fixation. HA ceramic coatings are mostly plasma sprayed onto the fixation surface of the implant. Plasma spraying is largely a 'line of sight' technique and as such there are difficulties involved when covering three-dimensional planes, such as porous beaded fixation surfaces typically found on several knee prostheses. The objective of this study was to assess the clinical performance of the solution-deposited HA coating, Peri-Apatitetrade mark , with regard to its ability to stimulate an endurable and stable implant fixation. PATIENTS AND METHODS: We randomised 60 patients into two groups; one group received the porous coated prosthesis with solution-deposited HA, and the other group received a prosthesis without HA. Radiostereometric examination was used as the primary tool for measuring migration in the prosthetic components. RESULTS: There was a lower incidence of early subsidence in the Peri-Apatitetrade mark group. At 24 months there were no differences in clinical scorings or maximal total point motion. CONCLUSION: Addition of solution-deposited HA coating appears to provide better early stable fixation in a porous coated knee prosthesis.
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| 17. |
- Hansson, Ulrik, et al.
(författare)
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Histologic reactions to particulate wear debris in different mesenchymal tissues : Studies on the nonreplaced compartment from revised uni-knees
- 2004
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Ingår i: The Journal of Arthroplasty. - : Elsevier BV. - 0883-5403 .- 1532-8406. ; 19:4, s. 481-487
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Tidskriftsartikel (refereegranskat)abstract
- The interface between bone and artificial-joint implants consists of soft tissue. This tissue varies from fibrocartilage to loose fibrous tissue. Tissues that resemble those can be found in normal joints. Sixteen knees with unicompartmental knee prostheses, revised because of excessive wear of the tibial insert, were studied. Synovium, synovial fluid, cartilage, and bone from the nonreplaced compartment were studied with light microscopy. We found wear particles and reactions to those in all tissues except cartilage. In the subchondral bone, we found osteolytic-like processes undermining the cartilage peripherally. Our conclusion from these findings is that the histologic composition of the bone-implant interface might be an important factor regarding the reaction of the tissue to wear particles and, thus, component fixation. © 2004 Elsevier Inc. All rights reserved.
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| 18. |
- Hansson, Ulrik, et al.
(författare)
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Mobile vs. fixed meniscal bearing in total knee replacement A randomised radiostereometric study.
- 2005
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Ingår i: Knee. - : Elsevier BV. - 1873-5800. ; 12:6, s. 414-418
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Tidskriftsartikel (refereegranskat)abstract
- 52 knees scheduled for a total knee arthroplasty were randomised to either a fixed or a mobile polyethylene bearing. The design was identical in all parts. The knee systems used were the Rotaglide Total Knee System (RTK) (R) and the Nuffield Total Knee System (NTK) (R), both from the same manufacturer (Corin Medical Ltd., UK). All knees implanted were uncemented. The patients were followed for 2 years clinically and with radiostereometric analyses to assess migration over time and inducible displacement of the tibial component. Separate analysis of the mobility of the tibial insert in the knees with a mobile bearing was also made. The migration measured with RSA between the I st and 2nd year expressed as maximum total point motion (MTPM) might predict the risk of loosening of the implant.
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| 19. |
- Hansson, Ulrik, et al.
(författare)
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Once-weekly oral medication with alendronate does not prevent migration of knee prostheses : A double-blind randomized RSA study
- 2009
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Ingår i: Acta Orthopaedica. - : Informa Healthcare. - 1745-3674 .- 1745-3682. ; 80:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- Background and purposeEarly migration of joint replacements is an effect of poor fixation and can predict late loosening. By reducing the bone resorption after implantation of a joint replacement, it should be possible to enhance the initial fixation of the implant. We studied the effect of once-weekly treatment with alendronate after knee replacement.Patients and methodsWe recruited 60 patients (60 knees) with gonarthrosis who were scheduled for a total knee replacement. They were operated on with identical implants and uncemented fixation. 30 patients were treated with a bisphosphonate (alendronate) and 30 patients underwent placebo treatment. The treatment started postoperatively and continued on a weekly basis for 6 months. The fixation of the implants was measured with repeated radiostereometry for 2 years.ResultsThere was no difference in migration of implants between the two groups.ConclusionWith uncemented fixation of knee implants, no benefit of once-weekly treatment with alendronate, starting postoperatively, could be seen during a 2-year follow-up period.
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| 20. |
- Hansson, Ulrik, et al.
(författare)
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Once-weekly oral medication with alendronate does not prevent migration of knee prostheses
- 2009
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3682 .- 1745-3674. ; 80:1, s. 41-45
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose Early migration of joint replacements is an effect of poor fixation and can predict late loosening. By reducing the bone resorption after implantation of a joint replacement, it should be possible to enhance the initial fixation of the implant. We studied the effect of once-weekly treatment with alendronate after knee replacement. Patients and methods We recruited 60 patients (60 knees) with gonarthrosis who were scheduled for a total knee replacement. They were operated on with identical implants and uncemented fixation. 30 patients were treated with a bisphosphonate (alendronate) and 30 patients underwent placebo treatment. The treatment started postoperatively and continued on a weekly basis for 6 months. The fixation of the implants was measured with repeated radiostereometry for 2 years. Results There was no difference in migration of implants between the two groups. Conclusion With uncemented fixation of knee implants, no benefit of once-weekly treatment with alendronate, starting postoperatively, could be seen during a 2-year follow-up period.
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| 21. |
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| 22. |
- Juliusson, Rigmor, et al.
(författare)
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Circulating blood diminishes cement penetration into cancellous bone. In vivo studies of 21 arthrotic femoral heads
- 1995
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Ingår i: Acta Orthopaedica Scandinavica. - 0001-6470. ; 66:3, s. 234-238
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Tidskriftsartikel (refereegranskat)abstract
- We compared the penetration depth into cancellous bone when pressurizing cement at predetermined pressure levels, and at different times after cement mixing, in 21 arthrotic femoral heads during total hip replacement. To determine the influence of circulating blood on cement penetration, cement was injected into holes drilled into the femoral head before and after osteotomy of the femoral neck. The penetration of cement increased on the average 100 percent in the absence of circulation.
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| 23. |
- Kiernan, Sverrir, et al.
(författare)
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The importance of adequate stem anteversion for rotational stability in cemented total hip replacement: A radiostereometric study with ten-year follow-up.
- 2013
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Ingår i: The Bone & Joint Journal. - 2049-4408. ; 95B:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- Progressive retroversion of a cemented stem is predictive of early loosening and failure. We assessed the relationship between direct post-operative stem anteversion, measured with CT, and the resulting rotational stability, measured with repeated radiostereometric analysis over ten years. The study comprised 60 cemented total hip replacements using one of two types of matt collared stem with a rounded cross-section. The patients were divided into three groups depending on their measured post-operative anteversion (< 10°, 10° to 25°, > 25°). There was a strong correlation between direct post-operative anteversion and later posterior rotation. At one year the < 10° group showed significantly more progressive retroversion together with distal migration, and this persisted to the ten-year follow-up. In the < 10° group four of ten stems (40%) had been revised at ten years, and an additional two stems (20%) were radiologically loose. In the 'normal' (10° to 25°) anteversion group there was one revised (3%) and one loose stem (3%) of a total of 30 stems, and in the > 25° group one stem (5%) was revised and another loose (5%) out of 20 stems. This poor outcome is partly dependent on the design of this prosthesis, but the results strongly suggest that the initial rotational position of cemented stems during surgery affects the subsequent progressive retroversion, subsidence and eventual loosening. The degree of retroversion may be sensitive to prosthetic design and stem size, but < 10° of anteversion appears deleterious to the long-term outcome for cemented hip prosthetic stems.Cite this article: Bone Joint J 2013;95-B:23-30.
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| 24. |
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| 25. |
- Lauge-Pedersen, Henrik, et al.
(författare)
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Arch-shaped versus flat arthrodesis of the ankle joint: strength measurements using synthetic cancellous bone
- 2002
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Ingår i: Proceedings of the Institution of Mechanical Engineers. Part H: Journal of Engineering in Medicine. - : SAGE Publications. - 0954-4119 .- 2041-3033. ; 216:H1, s. 43-49
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Tidskriftsartikel (refereegranskat)abstract
- The aim Of this Study was to see if preservation of the arch shape of the ankle at arthrodesis contributes to stability. The ankle joint was simulated by paired blocks of a synthetic material corresponding to rheumatoid cancellous bone with low stiffness and strength. Flat end constructs with and without subchondral bone were compared with arch-shape constructs with and without subchondral bone. The pairs were fixed with two screws simulating an arthrodesis. These constructs were then tested to failure in four-point bending and torque. In four-point bending the subchondral bone increased the strength, regardless of shape. Stiffness was higher in the arch-shaped specimens but was not influenced b the subchondral bone. In torque, both arch-shape and subchondral bone increase the strength. Stiffness was increased by arch-shape but not subchondral bone. The results imply that the arch-shape and subchondral bone should be preserved when performing an ankle arthrodesis, especially in weak rheumatoid bone.
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