| 1. |
- Callary, Stuart A, et al.
(author)
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The 6-Year Migration Characteristics of a Hydroxyapatite-Coated Femoral Stem A Radiostereometric Analysis Study
- 2012
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In: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 27:7, s. 1344-1348
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Journal article (peer-reviewed)abstract
- A prospective cohort of 30 patients undergoing primary total hip arthroplasty for treatment of osteoarthritis was enrolled in a study to characterize the migration behavior of a clinically successful cementless stem. At 6 years, the mean subsidence of the stem was 0.63 mm (range, -0.33 to 3.68 mm); the mean rotation into retroversion was 1.41° (range, -1.33° to 7.48°). No stems had additional subsidence of more than 0.25 mm between 6 months and 6 years. The resultant mean subsidence between 2 and 6 years was 0.03 mm, which is below the limit measurable by radiostereometric analysis. The data demonstrate that subsidence of this cementless stem occurs within the first 6 months, after which there is persistent stabilization.
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| 2. |
- Callary, Stuart A., et al.
(author)
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Wear of a 5 Megarad Cross-linked Polyethylene Liner : A 6-year RSA Study
- 2013
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 471:7, s. 2238-2244
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Journal article (peer-reviewed)abstract
- One cross-linked polyethylene (XLPE) liner is manufactured using a lower dose of radiation, 5 Mrad, which may result in less cross-linking. The reported in vivo wear rate of this XLPE liner in patients undergoing THA has varied, and has included some patients in each reported cohort who had greater than 0.1 mm/year of wear, which is an historical threshold for osteolysis. Previous studies have measured wear on plain radiographs, an approach that has limited sensitivity. We therefore measured the amount and direction of wear at 6 years using Radiostereometric analysis (RSA) in patients who had THAs that included a cross-linked polyethylene liner manufactured using 5 Mrad radiation. We prospectively reviewed wear in 30 patients who underwent primary THAs with the same design of cross-linked acetabular liner and a 28-mm articulation. Tantalum markers were inserted during surgery and all patients had RSA radiographic examinations at 1 week, 6 months, 1, 2, and 6 years postoperatively. The mean proximal, two-dimensional (2-D) and three-dimensional (3-D) wear rates calculated between 1 year and 6 years were 0.014, 0.014, and 0.018 mm/per year, respectively. The direction of the head penetration recorded between 1 week and 6 years was in a proximal direction for all patients, proximolateral for 16 of 24 patients, and proximomedial for eight of 24 patients. The proximal, 2-D and 3-D wear of a XLPE liner produced using 5 Mrad of radiation was low but measurable by RSA after 6 years. No patients had proximal 2-D or 3-D wear rates exceeding 0.1 mm/year. Further followup is needed to evaluate the effect of XLPE wear particles on the development of long-term osteolysis.
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| 3. |
- Campbell, David, et al.
(author)
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Case report : Cementless stem stabilization after intraoperative fracture: A radiostereometric analysis
- 2010
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In: Clinical Orthopaedics and Related Research. - : Ovid Technologies (Wolters Kluwer Health). - 0009-921X .- 1528-1132. ; 468:3, s. 898-901
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Journal article (peer-reviewed)abstract
- We present the case of a patient with intraoperative femoral fracture during THA, which was repaired using cerclage fixation and insertion of an hydroxyapatite-coated cementless stem. The patient was evaluated postoperatively using radiostereometry during a 2-year course, and despite a large amount of subsidence and rotation, stabilization occurred and was maintained by 6 months. By evaluating the pattern of stem migration after intraoperative fracture, this case shows, even in the presence of instability, a successful clinical outcome can be achieved using an hydroxyapatite-coated cementless stem.
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| 4. |
- Campbell, David, et al.
(author)
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Early migration characteristics of a hydroxyapatite-coated femoral stem : an RSA study.
- 2011
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In: International Orthopaedics. - : Springer. - 0341-2695 .- 1432-5195. ; 35:4, s. 483-488
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Journal article (peer-reviewed)abstract
- Measurement of early stem subsidence can be used to predict the likelihood of long-term femoral component loosening and clinical failure. Data that examines the early migration pattern of clinically proven stems will provide clinicians with useful baseline data with which to compare new stem designs. This study was performed to evaluate the early migration pattern of a hydroxyapatite-coated press-fit femoral component that has been in use for over ten years. We enrolled 30 patients who underwent THA for osteoarthritis. The median age was 70 years (range, 55-80 years). Patients were clinically assessed using the Harris hip score. Radiostereometric analysis was used to evaluate stem migration at three to four days, six months, one year and two years. We observed a mean subsidence of 0.73 mm at six months, 0.62 mm at one year and 0.58 mm at two years and a mean retroversion of 1.82° at six months, 1.90° at one year and 1.59° at two years. This data suggests that subsidence is confined to the first six months after which there was no further subsidence. The results from this study can be compared with those from novel cementless stem designs to help predict the long-term outcome one may expect from new cementless stem designs.
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| 5. |
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| 6. |
- Otten, Volker T C, et al.
(author)
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Osteolysis around uncemented cups withand without screw holes : Analysis of osteolytic lesions on CT images in 48 hips at a 14-year follow-up
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Other publication (other academic/artistic)abstract
- Osteolysis around uncemented cups is a major complication for THA. We present a 14-year follow-up of 48 hips previously randomized to four groups of cup fixation – sealed cups with press-fit only, cups with hydroxyapatite coating, cups with screws, and cups with pegs. CT scans revealed three types of osteolytic lesions – Type 1A (absence of trabecular bone and a sclerotic border), Type 1B (absence of trabecular bone without a sclerotic border), and Type 2 (reductions in radiodensity and trabeculae). Cups with screw-holes were surrounded with larger osteolytic lesions that were predominantly Type 1A. Unsealed screw holes in uncemented cups appeared to be a risk factor for osteolysis development. Modern CT scans reveal three types of osteolytic lesions. Distinction between types is important for comparability between studies.
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