| 1. |
- Bodén, Henrik
(författare)
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A clinical study of uncemented hip arthroplasty : radiological findings of host-bone reaction to the stem
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In total hip arthroplasty (THA), the main reason for failure leading to revision is aseptic loosening. Both mechanical and biological effects act in the loosening process, the factors may be implant design, fixation mode or technique, as well as biological factors unique to the individual. Younger and more active patients have a worse outcome compared to older patients. In an attempt to reduce the incidence of aseptic loosening, uncemented implants were introduced. The load that is transferred over the artificial joint is taken up by the femoral implant and a significant fraction of the load is transferred further distally to the host bone. An adaptive bone remodelling occurs and is commonly discussed in terms of stress-shielding. The general aim of the study was to evaluate the outcome after operation with an uncemented femoral stem and how the femoral host bone reacts in terms of adaptive remodelling. Material and Methods: Two types of tapered uncemented stems were evaluated. One stem with the surface coated with polytetrafluoroethylene, designed to enhance fibrous tissue ingrowth (Anaform®). One titanium stem with a proximal porous and hydroxyapatite coating, designed for bone ingrowth (Bi-Metric®). Clinical outcome was evaluated with the Harris Hip Score. Changes in bone mineral density (BMD) were assessed by Dual-energy X-ray Absorptiometry (DEXA). Bone metabolism was assessed by scintigraphy and radiological changes were noted using the criteria of Engh et al. Study I: The two types of stems were compared eight years postoperatively. The stem coated with polytetrafluoroethylene showed signs of instability and a more generalized distribution of bone resorption. The proximally coated stem showed most pronounced resorption proximally, despite only proximal coating. Study II: In a randomized controlled study, immediate and late weight-bearing after uncemented THA, were evaluated. Immediate weight-bearing had a positive effect on BMD around the prosthesis. No adverse clinical or radiological sign were detected. Study III: In 138 patients with unilateral uncemented stems, BMD was evaluated after a mean of 41 months. The size of uncemented stems was found to correlate with periprosthetic BMD. Bone loss in the proximal periprosthetic regions was significantly associated with larger stem sizes. Study IV: 104 hips in 95 patients were followed for a minimum of 10 years after uncemented THA with the Bi-Metric® stem. Excellent radiological results were noted for the stem. No stem was revised and no sign of loosening was detected, despite an inferior result on the acetabular side with 23 failures. However, progressive remodelling was noted on the femoral side, also between five and ten years. Study V: Two groups of 14 patients were followed for 10 and 14 years with DEXA and radiographs after implantation of the Bi-Metric® stem. At follow-up, a continuing decrease in BMD up to 14 years was noted in the calcar region. In conclusion, fibrous fixation of an uncemented stem is insufficient. A tapered titanium stem, porous and hydroxyapatite coated in the proximal region, showed signs of bone ingrowth and excellent clinical result after 10-14 years. Radiological signs of stress-shielding and proximal periprosthetic bone resorption are continuous up to 14 years.
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| 2. |
- Brodén, Cyrus, et al.
(författare)
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High risk of early periprosthetic fractures after primary hip arthroplasty in elderly patients using a cemented, tapered, polished stem : an observational, prospective cohort study on 1,403 hips with 47 fractures after mean follow-up time of 4 years
- 2015
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 86:2, s. 169-174
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Postoperative periprosthetic femoral fracture (PPF) after hip arthroplasty is associated with considerable morbidity and mortality. We assessed the incidence and characteristics of periprosthetic fractures in a consecutive cohort of elderly patients treated with a cemented, collarless, polished and tapered femoral stem (CPT). Patients and methods - In this single-center prospective cohort study, we included 1,403 hips in 1,357 patients (mean age 82 (range 52-102) years, 72% women) with primary osteoarthritis (OA) or a femoral neck fracture (FNF) as indication for surgery (367 hips and 1,036 hips, respectively). 64% of patients were ASA class 3 or 4. Hip-related complications and need for repeat surgery were assessed at a mean follow-up time of 4 (1-7) years. A Cox regression analysis was used to evaluate risk factors associated with PPF. Results - 47 hips (3.3%) sustained a periprosthetic fracture at median 7 (2-79) months postoperatively; 41 were comminute Vancouver B2 or complex C-type fractures. The fracture rate was 3.8% for FNF patients and 2.2% for OA patients (hazard ratio (HR) = 4; 95% CI: 1.3-12). Patients > 80 years of age also had a higher risk of fracture (HR = 2; 95% CI: 1.1-4.5). Interpretation - We found a high incidence of early PPF associated with the CPT stem in this old and frail patient group. A possible explanation may be that the polished tapered stem acts as a wedge, splitting the femur after a direct hip contusion. Our results should be confirmed in larger, registry-based studies, but we advise caution when using this stem for this particular patient group.
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| 3. |
- Chammout, Ghazi, et al.
(författare)
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Primary hemiarthroplasty for the elderly patient with cognitive dysfunction and a displaced femoral neck fracture : a prospective, observational cohort study
- 2021
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Ingår i: Aging Clinical and Experimental Research. - : Springer. - 1594-0667 .- 1720-8319. ; 33:5, s. 1275-1283
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Tidskriftsartikel (refereegranskat)abstract
- Background: At least one-third of hip fracture patients have some degree of impaired cognitive status, which may complicate their postoperative rehabilitation.Aim: We aimed to describe the outcome for elderly patients with cognitive dysfunction operated with hemiarthroplasty (HA) for a femoral neck fracture and to study the impact postoperative geriatric rehabilitation has on functional outcome up to 1 year after surgery.Methods: 98 patients with a displaced femoral neck fracture with a mean age of 86 years were included and followed up to 1 year. The outcomes were hip-related complications and reoperations, the capacity to return to previous walking ability, health-related quality of life, hip function and mortality.Results: The prevalence of hip complications leading to a major reoperation was 6% and the 1-year mortality rate was 31%. The lack of geriatric rehabilitation was correlated with poorer outcomes overall and those who receive geriatric rehabilitation were less likely to be confined to a wheelchair or bedridden at the 1-year follow-up.Conclusions: Hemiarthroplasty is an acceptable option for elderly patients with a displaced femoral neck fracture and cognitive dysfunction. A lack of structured rehabilitation is associated with a significant deterioration in walking ability despite a well-functioning hip. However, the causality of this could be due to selection bias of healthier patients being sent to geriatric rehabilitation.
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| 4. |
- Ip, H. F., et al.
(författare)
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Genetic association study of childhood aggression across raters, instruments, and age
- 2021
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Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Childhood aggressive behavior (AGG) has a substantial heritability of around 50%. Here we present a genome-wide association metaanalysis (GWAMA) of childhood AGG, in which all phenotype measures across childhood ages from multiple assessors were included. We analyzed phenotype assessments for a total of 328 935 observations from 87 485 children aged between 1.5 and 18 years, while accounting for sample overlap. We also meta-analyzed within subsets of the data, i.e., within rater, instrument and age. SNP-heritability for the overall meta-analysis (AGGoverall) was 3.31% (SE= 0.0038). We found no genome-wide significant SNPs for AGG(overall). The gene-based analysis returned three significant genes: ST3GAL3 (P= 1.6E-06), PCDH7 (P= 2.0E-06), and IPO13 (P= 2.5E-06). All three genes have previously been associated with educational traits. Polygenic scores based on our GWAMA significantly predicted aggression in a holdout sample of children (variance explained = 0.44%) and in retrospectively assessed childhood aggression (variance explained = 0.20%). Genetic correlations (rg) among rater-specific assessment of AGG ranged from r(g)= 0.46 between self- and teacher-assessment to r(g)d= 0.81 between mother- and teacher-assessment. We obtained moderate-to-strong rgs with selected phenotypes from multiple domains, but hardly with any of the classical biomarkers thought to be associated with AGG. Significant genetic correlations were observed with most psychiatric and psychological traits (range r(g): 0.19-1.00), except for obsessive-compulsive disorder. Aggression had a negative genetic correlation (r(g)=-0.5) with cognitive traits and age at first birth. Aggression was strongly genetically correlated with smoking phenotypes (range |r(g)| : 0.46-0.60). The genetic correlations between aggression and psychiatric disorders were weaker for teacher-reported AGG than for mother- and self-reported AGG. The current GWAMA of childhood aggression provides a powerful tool to interrogate the rater-specific genetic etiology of AGG.
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| 5. |
- Persson, Anders, et al.
(författare)
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Revision for Symptomatic Pseudotumor After Primary Metal-on-Polyethylene Total Hip Arthroplasty with a Standard Femoral Stem.
- 2018
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Ingår i: The Journal of bone and joint surgery. American volume. - 1535-1386. ; 100:11, s. 942-949
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Tidskriftsartikel (refereegranskat)abstract
- Pseudotumor formation following total hip arthroplasty (THA) is a well-known complication mainly associated with metal-on-metal (MoM) bearings and taper corrosion on modular-neck femoral stems. The purpose of this study was to determine the prevalence of revision surgery for symptomatic pseudotumors in a large cohort of patients treated with primary THA with a standard stem and a non-MoM articulation.We included 2,102 patients treated with a total of 2,446 THAs from 1999 until May 2016 in a prospective, observational cohort study. All patients underwent THA with the same uncemented, non-modular-neck femoral stem and metal-on-polyethylene (MoP) (n = 2,409) or ceramic-on-polyethylene (n = 37) articulation. All patients were followed by means of a combination of surgical and medical chart review, follow-up visits, and the Swedish Hip Arthroplasty Register. Metal artifact reduction sequence magnetic resonance imaging (MARS MRI) was used for diagnosis of the pseudotumors, and serum metal ion levels and inflammatory marker levels were measured for all patients who underwent a revision due to pseudotumor.The prevalence of revision for symptomatic pseudotumor formation was 0.5% (13 cases) at a mean follow-up time of 7 years. The incidence rate was 0.9 case per 1,000 person-years. All 13 revisions were done in patients with an MoP articulation.This study demonstrated a 0.5% prevalence of revision due to symptomatic pseudotumor formation in a cohort of patients who underwent THA with a non-MoM construct. Surgeons should be aware that symptomatic pseudotumor formation requiring revision surgery is a tangible complication even after standard MoP THA.Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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| 6. |
- Sköldenberg, Olof G., et al.
(författare)
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A randomized double-blind noninferiority trial, evaluating migration of a cemented vitamin E-stabilized highly crosslinked component compared with a standard polyethylene component in reverse hybrid total hip arthroplasty
- 2019
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Ingår i: The Bone & Joint Journal. - : The British Editorial Society of Bone & Joint Surgery. - 2049-4394 .- 2049-4408. ; 101-B:10, s. 1192-1198
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Radiostereometric analysis (RSA) studies of vitamin E-doped, highly crosslinked polyethylene (VEPE) liners show low head penetration rates in cementless acetabular components. There is, however, currently no data on cemented VEPE acetabular components in total hip arthroplasty (THA). The aim of this study was to evaluate the safety of a new cemented VEPE component, compared with a conventional polyethylene (PE) component regarding migration, head penetration, and clinical results.PATIENTS AND METHODS: We enrolled 42 patients (21 male, 21 female) with osteoarthritis and a mean age of 67 years (sd 5), in a double-blinded, noninferiority, randomized controlled trial. The subjects were randomized in a 1:1 ratio to receive a reverse hybrid THA with a cemented component of either argon-gas gamma-sterilized PE component (controls) or VEPE, with identical geometry. The primary endpoint was proximal implant migration of the component at two years postoperatively measured with RSA. Secondary endpoints included total migration of the component, penetration of the femoral head into the component, and patient-reported outcome measurements.RESULTS: In total, 19 control implants and 18 implants in the VEPE group were analyzed for the primary endpoint. We found a continuous proximal migration of the component in the VEPE group that was significantly higher with a difference at two years of a mean 0.21 mm (95% confidence interval (CI) 0.05 to 0.37; p = 0.013). The total migration was also significantly higher in the VEPE group, but femoral head penetration was lower. We found no difference in clinical outcomes between the groups.CONCLUSION: At two years, this cemented VEPE component, although having a low head penetration and excellent clinical results, failed to meet noninferiority compared with the conventional implant by a proximal migration above the proposed safety threshold of RSA. The early proximal migration pattern of the VEPE component is a reason for continued monitoring, although a specific threshold for proximal migration and risk for later failure cannot be defined and needs further study.
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