| 1. |
- Angelomenos, Vasileios, et al.
(författare)
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A prospective randomized study of Refobacin Bone Cement R versus Palacos R plus G FEMORAL COMPONENT MIGRATION AT TWO YEARS POSTOPERATIVELY
- 2024
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Ingår i: BONE & JOINT JOURNAL. - 2049-4394. ; 106B:5, s. 435-441
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Tidskriftsartikel (refereegranskat)abstract
- Aims Refobacin Bone Cement R and Palacos R + G bone cement were introduced to replace the original cement Refobacin Palacos R in 2005. Both cements were assumed to behave in a biomechanically similar fashion to the original cement. The primary aim of this study was to compare the migration of a polished triple- tapered femoral stem fixed with either Refobacin Bone Cement R or Palacos R + G bone cement. Repeated radiostereometric analysis was used to measure migration of the femoral head centre. The secondary aims were evaluation of cement mantle, stem positioning, and patient- reported outcome measures. Methods Overall, 75 patients were included in the study and 71 were available at two years postoperatively. Prior to surgery, they were randomized to one of the three combinations studied: Palacos cement with use of the Optivac mixing system, Refobacin with use of the Optivac system, and Refobacin with use of the Optipac system. Cemented MS30 stems and cemented Exceed acetabular components were used in all hips. Postoperative radiographs were used to assess the quality of the cement mantle according to Barrack et al, and the position and migration of the femoral stem. Harris Hip Score, Oxford Hip Score, Forgotten Joint Score, and University of California, Los Angeles Activity Scale were collected. Results Median distal migration (y - axis) at two years for the Refobacin- Optivac system was -0.79 mm (- 2.01 to -0.09), for the Refobacin- Optipac system was -0.75 mm (- 2.16 to 0.20), and for the Palacos- Optivac system was -1.01 mm (- 4.31 to -0.29). No statistically significant differences were found between the groups. Secondary outcomes did not differ statistically between the groups at the two- year follow- up. Conclusion At two years, we found no significant differences in distal migration or clinical outcomes between the three groups. Our data indicate that Refobacin Bone Cement R and Palacos R + G are comparable in terms of stable fixation and early clinical outcomes.
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| 2. |
- Angelomenos, Vasileios, et al.
(författare)
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Precision of low-dose CT-based micromotion analysis technique for the assessment of early acetabular cup migration compared with gold standard RSA: a prospective study of 30 patients up to 1 year
- 2022
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 93, s. 459-465
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Computed tomography micromotion analysis (CTMA) can be used to determine implant micro-movements using low-dose CT scans. By using CTMA, a non-invasive measurement of joint implant movement is enabled. We evaluated the precision of CTMA in measuring early cup migration. Standard marker-based radiostereometric analysis (RSA) was used as reference. We hypothesised that CTMA can be used as an alternative to RSA in assessing implant micromotions. Patients and methods - We included 30 patients undergoing total hip arthroplasty (THA). Acetabular cup migration at 1 year was measured with RSA and CTMA. To determine the precision of both methods, 20 double examinations (postoperatively) with repositioning of the patients were performed. The precision was calculated from zero by assuming that there was no motion of the prosthesis between the 2 examinations. Results - The precision of RSA ranged from 0.06 to 0.15 mm for translations and 0.21 degrees to 0.63 degrees for rotations. Corresponding values for CTMA were 0.06 to 0.13 mm and 0.23 degrees to 0.35 degrees. A good level of agreement was found between the methods regarding cup migration and rotation at 1 year. Interpretation - The precision of CTMA in measuring acetabular cup migration and rotation is comparable to marker-based RSA. CTMA could possibly thus be used as an alternative method to detect early implant migration.
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| 3. |
- Itayem, Raed, et al.
(författare)
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A two-year radiostereometric follow-up of the first generation Birmingham mid head resection arthroplasty.
- 2014
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Ingår i: HIP International. - : SAGE Publications. - 1120-7000 .- 1724-6067. ; 24:4, s. 355-62
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Tidskriftsartikel (refereegranskat)abstract
- During the first decade of the 21st century, metal-on-metal hip resurfacing became one of the main treatment options for younger, more active patients with osteoarthritis. However, as a result of the reported failure rate of both total hip replacement (THR) and resurfacing in patients with considerable loss of bone stock in the femoral head (e.g., in extensive avascular necrosis), other solutions have been sought for these patients. The short-stemmed Birmingham Mid Head Resection prosthesis (BMHR) combines a metal-on-metal articulation and a femoral neck preserving feature. In this study, radiostereometric analysis (RSA) was used to study migration of the BMHR femoral component in 13 hips. Translations and rotations were measured up to two years. Relative values showed no statistically significant migration. Absolute values demonstrated settling in occurring between zero and two months postoperatively in all directions studied. From two months to two years no significant migration occurred except for rotation around the x-axis of the femoral segment (p = 0.049). After initial settling-in, absolute values were low, indicating that there was no evidence of early migration or loosening of the components.
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| 4. |
- Itayem, Raed, 1967, et al.
(författare)
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Influence of implant variations on survival of the Lubinus SP II stem: evaluation of 76,530 hips in the Swedish Arthroplasty Register, 2000-2018.
- 2022
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Ingår i: Acta orthopaedica. - : Medical Journals Sweden AB. - 1745-3682 .- 1745-3674. ; 93, s. 37-42
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Almost all prosthetic implant brands include several variations. Most studies on implant performance investigate an implant system without sub-analysis of implant attributes. We studied the influence of design variations during the last 2 decades on implant survival of the most frequently used cemented femoral stem, the Lubinus SPII, reported to the Swedish Arthroplasty Register (SHAR). Patients and methods - Between 2000 and 2018, 100,032 cemented Lubinus SP II stems had been reported to SHAR. Patients with primary osteoarthritis operated on with stem length 150 mm together with a cemented cup from the same manufacturer (n = 76,530) were included in this analysis. Primary study outcome was non-infectious stem revision. Cox regression with adjustment for age, sex, surgical approach, and year of surgery was used. Hazard rates (HR) are presented with 95% confidence intervals (CI). Results - Average follow-up was 7.6 years (SD 4.2). At 18 years the overall stem survival was 99.1 (CI 98.9-99.3). Increased revision rate was observed for stems with extra offset, when a long or an extra-long head length had been used. Smaller stem sizes, in particular the smallest stem size (01), substantially increased the rate of mechanical failure as reflected by an almost 10 times increased rate of revision compared with the standard size (2). Interpretation - In this study with larger sample size and longer follow-up than previously presented from the same register, we observed more pronounced effects of previously documented design variations. Based on our results, surgeons using the Lubinus SPII stems are advised to consider an alternative solution if a Lubinus stem size 01, Lubinus extra offset, or an extra-long head seems to be the most suitable choice at the preoperative planning.
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| 5. |
- Itayem, Raed
(författare)
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On fixation of hip resurfacing implants
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hip resurfacing became a recognized entity in hip replacement in the 1970’s. This generation of resurfacing implants was abandoned due to loosening and debris. The interest in resurfacing was renewed due to the need of a bone conservative solution for young active patients with osteoarthritis, and a new generation metal on metal (MoM) resurfacing implants was introduced in the late 1990’s using the same alloy as in earlierMoM total hip replacements (THR’s). Although sharing similar resurfacing features, they could differ in aspects such as fixation method, design features and manufacturing process. Radiostereometric analysis (RSA) is the golden standard method to study micromotion in hip and knee implants; early micromotion is a strong indicator for loosening and poor long term survival. No RSA studies had been performed on earlier MoM THR´s. This meant that it was important to perform RSA studies on the new MoM resurfacing implants. In Studies I-II, RSA examinations were performed on the Birmingham Hip Resurfacing Implant (BHR), to investigate whether translation and or rotation occurred early postoperatively (Study I) and at mid term (Study II). In Study III, a two year RSA follow - up was performed on the Birmingham Mid Head Resection (BMHR) implants. The results demonstrated stable implants during the periods studied, indicating that fixation and stability should not contribute to eventual failure. One MoM resurfacing device, the Articular Surface Replacement (ASR) was recalled from clinical use in 2010 due to inferior outcome. Femoral head implant loosening and femoral neck fractures indicating instability of fixation were dominant causes at short term. The cementing technique for ASR fixation (high viscosity (HV), indirect) differed from the technique used for clinically successful resurfacing implants (low viscosity (LV), direct). Study IV was an investigation using a cadaver model, to clarify morphological differences between the HV and LV cementing techniques on ASR implants. The results demonstrated a superficial fixation with the HV technique, which in traditional hip and knee implants has been demonstrated to be favourable, but may in the ASR be insufficient to maintain adequate stable fixation. The use of the resurfacing method has declined since the ASR withdrawal, although other issues concerning the long term effects of elevated ion levels also contributed to the decline. The ASR experience underlines the importance of thorough studies of factors such as migration and wear before general market introduction of new implants.
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| 6. |
- Itayem, Raed, 1967, et al.
(författare)
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What is the Role of Stem Size and Offset in the Risk of Nonseptic Revision of the Exeter & REG; 150-mm Stem? A Study From the Swedish Arthroplasty Register
- 2023
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Ingår i: Clinical Orthopaedics and Related Research. - 0009-921X. ; 481:9, s. 1689-1699
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe Exeter & REG; stem is used worldwide, often in older patients, and it is the second most commonly used cemented stem design in Sweden. Previous studies have shown that for cemented stems with a composite beam, the smallest sizes result in an increased risk of revision for mechanical failure. However, little is known about whether the survivorship of the polished Exeter stem, which generally has been shown to be good, might be associated with design parameters such as stem dimensions or offset at extreme implant sizes.Question/purposeAre differences in (1) stem size or (2) offset of the standard Exeter V40 150-mm stem associated with differences in the risk of stem revision for aseptic loosening?MethodsBetween 2001 and 2020, 47,161 Exeter stems were reported to the Swedish Arthroplasty Register, with very high coverage and completeness documented during the period studied. In this cohort, we included patients with primary osteoarthritis who underwent surgery with a standard Exeter stem length of 150 mm and V40 cone with any type of cemented cups that had had at least 1000 reported insertions. This selection resulted in a study cohort representing 79% (37,619 of 47,161) of the total number of Exeter stems in the registry during that time. The primary study outcome was stem revision for aseptic indications such as loosening, periprosthetic fracture, dislocation, and implant fracture. A Cox regression was performed, with adjustment for age, gender, surgical approach, year of surgery, use of highly crosslinked polyethylene cups, and femoral head size and length dictated by the shape of the head trunnion. Adjusted hazard ratios are presented with 95% confidence intervals. Two separate analyses were performed. The first analysis excluded stems with the highest offsets (50 mm and 56 mm, which were not available for stem size 0). The second analysis excluded stem size 0 to include all offsets. Because stem survival was not proportional over time, we divided the analyses into two insertion periods, 0 to 8 years and beyond 8 years.ResultsStem size 0 (compared to size 1) was associated with an increased risk of revision up to 8 years when all stem sizes were included (first analysis 0 to 8 years, HR 1.7 [95% CI 1.2 to 2.3]; p = 0.002). Forty-four percent (63 of 144) of revisions of size 0 stems were for periprosthetic fracture. There was no consistent association between stem size and risk of aseptic stem revision when size 0 was excluded in the second analysis beyond 8 years. The most common offset (44 mm) was associated with an increased risk of revision (compared with 37.5 mm) up to 8 years when all sizes were included (first analysis, HR 1.6 [95% CI 1.1 to 2.1]; p = 0.01). In the second analysis (beyond 8 years, all offsets included), offset of 44 mm was compared with offset of 37.5 mm; compared with the first period, this offset was associated with a reduced risk (HR 0.6 [95% CI 0.4 to 0.9]; p = 0.005).ConclusionWe found overall high survival of the Exeter stem, with generally little or no influence of stem variations on the risk of aseptic revision. However, stem size 0 was associated with an increased risk of revision mainly for periprosthetic fractures. If the femoral anatomy offers a choice between sizes 0 and 1 in patients with poor bone quality who are at risk of periprosthetic fracture, our data speak in favor of choosing the larger stem if the surgeon believes it is safe to insert the larger size, or, if available, another stem design that has a documented lower risk of this complication. For patients with good cortical bone quality but very narrow canals, a cementless stem may also be a good alternative.
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| 7. |
- Oxblom, A., et al.
(författare)
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Careful patient selection together with optimal implant positioning may reduce but does not eliminate the risk of elevated serum cobalt and chrome levels following metal-on-metal hip resurfacing
- 2023
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Ingår i: Hip International. - : SAGE Publications. - 1120-7000 .- 1724-6067. ; 33:5, s. 872-879
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Tidskriftsartikel (refereegranskat)abstract
- Background: Elevated serum chrome (sCr) and cobalt (sCo) concentrations are associated with local tissue adverse reactions to metal debris following metal-on-metal hip resurfacing (MoM-HR). Serum metal ions 5 mu g/l. Patients and methods: This is a retrospective, single-institution cohort study of 410 consecutive patients operated on with a Birmingham Hip Resurfacing (BHR) implant between 2001 and 2014. 288 of these had a unilateral MoM-HR, pelvic and true lateral radiographs, and a related sCo and sCr sample, and were included in the final analysis. They were allocated to either a presumed "optimal group" consisting of only men aged <60 years old, with femoral head component >48 mm diameter, and with a cup positioned within Lewinnek's safe zones, or a "suboptimal group" consisting of the remaining patients. Fisher ' s exact test and multiple logistic regression analyses were performed. Results: In the optimal group 48% (47/97) had serum metal ions >2 mu g/l and 8% (8/97) >5 mu g/l compared to 61% (116/191) and 18% (34/191) in the suboptimal group, p = 0.059 and p = 0.034 respectively. Acetabular cups with an anteversion <5 degrees had the highest odds ratio, 6.5 (95% CI, 3.0-14.3), of having sCo and sCr concentrations exceeding 5 mu g/l. Conclusions: A well oriented BHR acetabular component in a presumably "optimal" patient reduces the risk of having elevated serum metal ions but does not eliminate it. Insufficient cup anteversion seems to be the strongest associated factor of elevated serum metals.
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