| 1. |
- Pyrhonen, H. S., et al.
(författare)
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No Difference in Conversion Rate to Hip Arthroplasty After Intramedullary Nail or Sliding Hip Screw for Extracapsular Hip Fractures An Observational Cohort Study of 19,604 Individuals
- 2022
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Ingår i: Journal of Bone and Joint Surgery-American Volume. - : Ovid Technologies (Wolters Kluwer Health). - 0021-9355 .- 1535-1386. ; 104:19, s. 1703-1711
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Tidskriftsartikel (refereegranskat)abstract
- Background: The widespread use of intramedullary nails (IMNs) compared with sliding hip screws (SHSs) in extracapsular hip fractures (AO/OTA 31-A1, 31-A2, 31-A3) has been questioned because of a higher complication rate, although the outcome might have improved through more recent implant designs and the learning curve. This study aimed to investigate if there is a difference with regard to the cumulative incidence of conversion to arthroplasty or any reoperation during the first 5 years after IMN or SHS fixation of extracapsular hip fractures. Methods: In this nationwide, observational cohort study, individuals who were >= 60 years of age and were registered in the Swedish Fracture Register (SFR) from 2012 to 2018 due to extracapsular fracture and were primarily treated with an IMN or SHS were followed in the SFR and the Swedish Arthroplasty Register (SAR) for a minimum of 1 year. The primary outcome was the cumulative incidence of conversion to arthroplasty (conversion rate). The secondary outcome was the cumulative incidence of all reoperations (reoperation rate). Both were calculated in a competing risk analysis during the first 5 years. Results: We included 19,604 individuals (70% women), with a median age of 85 years (range, 60 to 107 years). The 31-A2 fracture was most prevalent (52%), followed by the 31-A1 fracture (28%). No significant differences were seen in the 1-year conversion rate after IMN or SHS use (1.0% compared with 0.9% in the 31-A1 fractures, 1.7% compared with 1.3% in the 31-A2 fractures, and 1.3% compared with 1.5% in the 31-A3 fractures) or in the 1-year reoperation rate (1.9% compared with 1.9% in the type-A1 fractures, 3.4% compared with 2.5% in the type-A2 fractures, and 4.0% compared with 5.2% in the type-A3 fractures). Only in 31-A2 fractures were more reoperations seen after IMN use at 2 and 5 years (p < 0.05). The crude 1-year-mortality was 26.4% (5,178 of 19,604), without significant differences between implants. Conclusions: Considering conversion arthroplasty, IMNs and SHSs performed equally well in general. IMN use was associated with more reoperations than SHS use in 31-A2 fractures at 2 years. However, from a clinical perspective, the differences between the implants were small, in particular when considering the competing risk of dying.
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| 2. |
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| 3. |
- Bojan, Alicja J., 1980, et al.
(författare)
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A new bone adhesive candidate- does it work in human bone? An ex-vivo preclinical evaluation in fresh human osteoporotic femoral head bone
- 2022
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Ingår i: Injury-International Journal of the Care of the Injured. - : Elsevier BV. - 0020-1383 .- 1879-0267. ; 53:6, s. 1858-1866
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The fixation of small intraarticular bone fragments is clinically challenging and an obvious first orthopaedic indication for an effective bone adhesive. In the present study the feasibility of bonding freshly harvested human trabecular bone with OsStic(R), a novel phosphoserine modified cement, was evaluated using a bone cylinder model pull-out test and compared with a commercial fibrin tissue adhesive. Methods: Femoral heads (n=13) were collected from hip fracture patients undergoing arthroplasty and stored refrigerated overnight in saline medium prior to testing. Cylindrical bone cores with a pre-inserted bone screw, were prepared using a coring tool. Each core was removed and glued back in place with either the bone adhesive (alpha-tricalcium phosphate, phosphoserine and 20% trisodium citrate solution) or the fibrin glue. All glued bones were stored in bone medium at 37 degrees C. Tensile loading, using a universal testing machine (5 kN load cell), was applied to each core/head. For the bone adhesive, bone cores were tested at 2 (n=13) and 24 (n=11) hours. For the fibrin tissue adhesive control group (n=9), bone cores were tested exclusively at 2 hours. The femoral bone quality was evaluated with micro-CT. Results: The ultimate pull-out load for the bone adhesive at 2 hours ranged from 36 to 171 N (mean 94 N, SD 42 N). At 24 hours the pull-out strength was similar, 47 to 198 N (mean 123 N, SD 43 N). The adhesive failure usually occurred through the adhesive layer, however in two samples, at 167 N and 198 N the screw pulled out of the bone core. The fibrin tissue adhesive group reached a peak force of 8 N maximally at 2 hours (range 2.8-8 N, mean 5.4 N, SD 1.6 N). The mean BV/TV for femoral heads was 0.15 and indicates poor bone quality. Conclusion: The bone adhesive successfully glued wet and fatty tissue of osteoporotic human bone cores. The mean ultimate pull-out force of 123 N at 24 hours corresponds to similar to 300 kPa shear stress acting on the bone core. These first ex-vivo results in human bone are a promising step toward potential clinical application in osteochondral fragment fixation. (C) 2022 The Authors. Published by Elsevier Ltd.
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| 4. |
- Bojan, Alicja J., 1980, et al.
(författare)
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Critical factors in cut-out complication after gamma nail treatment of proximal femoral fractures.
- 2013
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Ingår i: BMC musculoskeletal disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The most common mechanical failure in the internal fixation of trochanteric hip fractures is the cut-out of the sliding screw through the femoral head. Several factors that influence this complication have been suggested, but there is no consensus as to the relative importance of each factor.The purpose of this study was to analyse the cut-out complication with respect to the following variables: patients' age, fracture type, fracture reduction, implant positioning and implant design. METHODS: 3066 consecutive patients were treated for trochanteric fractures with Gamma Nails between 1990 and 2002 at the Centre de Traumatologie et de l`Orthopedie (CTO), Strasbourg, France. Cut-out complications were identified by reviewing all available case notes and radiographs. Subsequently, the data were analysed by a single reviewer (AJB) with focus on the studied factors. RESULTS: Seventy-one cut-out complications were found (2.3%) of the 3066 trochanteric fractures. Cut-out failure associated with avascular head necrosis, pathologic fracture, deep infection or secondary to prior failure of other implants were excluded from the study (14 cases). The remaining 57 cases (1.85 %, median age 82.6, 79% females) were believed to have a biomechanical explanation for the cut-out failure. 41 patients had a basicervical or complex fracture type. A majority of cut-outs (43 hips, 75%) had a combination of the critical factors studied; non-anatomical reduction, non-optimal lag screw position and the characteristic fracture pattern found. CONCLUSIONS: The primary cut-out rate of 1.85% was low compared with the literature. A typical cut-out complication in our study is represented by an unstable fracture involving the trochanteric and cervical regions or the combination of both, non-anatomical reduction and non-optimal screw position. Surgeons confronted with proximal femoral fractures should carefully scrutinize preoperative radiographs to assess the primary fracture geometry and fracture classification. To reduce the risk of a cut-out it is important to achieve both anatomical reduction and optimal lag screw position as these are the only two factors that can be controlled by the surgeon.
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| 5. |
- Bojan, Alicja J., 1980, et al.
(författare)
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Three-dimensional bone-implant movements in trochanteric hip fractures. Precision and accuracy of radiostereometric analysis in a phantom model.
- 2015
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Ingår i: Journal of orthopaedic research : official publication of the Orthopaedic Research Society. - : Wiley. - 1554-527X. ; 33:5, s. 705-11
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy and precision of RSA was evaluated in the experimental study of screw cut-out complication after fixation of trochanteric fractures. A plastic bone model of a two-part trochanteric fracture was constructed with a Gamma nail implant incorporating RSA markers. The femoral head fragment was attached to a separate rotational table and the femoral shaft was mounted on the micrometer. Three main motions were simulated: femoral head translation and rotation along the axis of the lag screw and fracture fragment translation along anatomical axes. Accuracy and precision were determined according to ISO 16087 and ASTM standard F2385-04. Translations along the lag screw axis were measured with a precision within±0.14mm and an accuracy within±0.03mm. With simultaneous translations along all three anatomical axes, lowest precision was measured for the x-axis (±0.29mm, 0.07mm respectively), but improved when analyzed as a vector (±0.08mm, 0.03mm). The precision and accuracy of femoral head rotations were within 0.5° and 0.18°, respectively. The resolution of the RSA method tested in this model was high, though it varied depending on the type of analyzed motion. This information is valuable when selecting and interpreting outcome parameters evaluating implant migration and osteosynthesis stability in future clinical RSA studies. This article is protected by copyright. All rights reserved.
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| 6. |
- Bojan, Alicja J., 1980, et al.
(författare)
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Trochanteric fracture-implant motion during healing - A radiostereometry (RSA) study
- 2018
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Ingår i: Injury-International Journal of the Care of the Injured. - : Elsevier BV. - 0020-1383. ; 49:3, s. 673-679
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Tidskriftsartikel (refereegranskat)abstract
- Cut-out complication remains a major unsolved problem in the treatment of trochanteric hip fractures. A better understanding of the three-dimensional fracture-implant motions is needed to enable further development of clinical strategies and countermeasures. The aim of this clinical study was to characterise and quantify three-dimensional motions between the implant and the bone and between the lag screw and nail of the Gamma nail. Radiostereometry Analysis (RSA) analysis was applied in 20 patients with trochanteric hip fractures treated with an intramedullary nail. The following three-dimensional motions were measured postoperatively, at 1 week, 3, 6 and 12 months: translations of the tip of the lag screw in the femoral head, motions of the lag screw in the nail, femoral head motions relative to the nail and nail movements in the femoral shaft. Cranial migration of the tip of the lag screw dominated over the other two translation components in the femoral head. In all fractures the lag screw slid laterally in the nail and the femoral head moved both laterally and inferiorly towards the nail. All femoral heads translated posteriorly relative to the nail, and rotations occurred in both directions with median values close to zero. The nail tended to retrovert in the femoral shaft. Adverse fracture-implant motions were detected in stable trochanteric hip fractures treated with intramedullary nails with high resolution. Therefore, RSA method can be used to evaluate new implant designs and clinical strategies, which aim to reduce cut-out complications. Future RSA studies should aim at more unstable fractures as these are more likely to fail with cut-out. (C) 2018 Elsevier Ltd. All rights reserved.
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| 7. |
- Bojan, Alicja J., 1980
(författare)
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Trochanteric Hip Fractures Clinical Outcomes and the Cut-out Complication
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The established treatment for trochanteric hip fractures is internal fixation, either intramedullary (nail) or extramedullary (plate). Approximately 10% of these patients suffer from mechanical complications, the most frequent one being perforation of the lag screw through the femoral head into the hip joint (cut-out). This condition is painful and disabling, and requires revision surgery. The purpose of this thesis was to gain better understanding of the cut-out complication. The complication rate was evaluated in the retrospective series of 3066 consecutive patients treated with an intramedullary nail in a single centre over a 12 years period. Cut-out was found to be the most frequent complication albeit lower than in previous literature - 1.85% (57 patients) (Studies I and II). Combination of three factors: a comminute fracture, poor fracture reduction and non-optimal implant positioning was associated with an increased cutout risk. From the range of cut-out patterns, i.e. screw cut-out in a variety of paths through the femoral head, it was observed to be a three-dimensional event. To further analyse the pre-cut-out movements, Radiostereometric Analysis (RSA) method was applied in trochanteric hip fractures treated with intramedullary nails (Studies III and IV). Firstly, an experimental study was undertaken to confirm the applicability of RSA in trochanteric fractures. A SawbonesTM model of a trochanteric fracture was mounted on micrometer screws, and radiographed with different true reference displacements. RSA was shown to have high precision and accuracy in this application as translations and rotations in the fracture-implant model could be detected to within ±0.14mm and ±0.03mm (translations), and ±0.5° and ±0.18° (rotations). The last study prospectively evaluated the 3D fracture-implant movements with the RSA method in 20 patients with stable trochanteric fractures treated with an intramedullary nail and followed for one year. Fracture-implant motion decreased after 3 months and no cut-out occurred. RSA detected clinically relevant movements: translation of the proximal tip of the lag screw in the femoral head, femoral head and lag screw movements relative to the nail. It is important to recognize the "fracture at risk" and, particularly in these patients, achieve anatomical fracture reduction and optimal implant placement. The migration of the implant in bone measured by RSA could be used as a cut-out predictor and enable evaluation of new treatment methods in small groups of patients.
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| 8. |
- Brandt Knutsson, Sara, et al.
(författare)
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Femoral fracture classification in the Swedish Fracture Register - A validity study
- 2019
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Ingår i: BMC Musculoskeletal Disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 The Author(s). Background: A total of more than 270,000 fractures are registered in the Swedish Fracture Register (SFR), a national quality register. Fractures are classified following the AO/OTA classification, commonly by a junior doctor. As a step in the process of validating the data in the SFR, several studies of the accuracy of the fracture classification have already been published. The aim of this study was to evaluate the accuracy of femoral fracture classification in the SFR. Methods: One hundred and eighteen femur fractures were randomly selected from the SFR. Three experienced orthopaedic surgeons individually classified these fractures on two separate occasions and a gold standard classification was established. This classification was compared with the original classification in the SFR. Inter- and intraobserver agreement was calculated. Results: The agreement between the classification in the SFR and the gold standard classification was kappa = 0.65 for the AO/OTA group and kappa = 0.83 for the AO/OTA type. This corresponds to substantial and almost perfect agreement, according to Landis and Koch. The kappa values for interobserver agreement ranged from 0.64-0.76 for the AO/OTA group and 0.76-0.85 for the AO/OTA type. The kappa values for intraobserver agreement ranged from 0.79-0.81 for the AO/OTA group and 0.91-0.93 for the AO/OTA type. Conclusions: The classification of femoral fractures in the Swedish Fracture Register is substantial (AO/OTA group) to almost perfect (AO/OTA type) and as accurate as in previous studies. The present study also shows that the agreement between the SFR classification and a gold standard classification is in the same range of agreement as between experienced raters. In contrast to previous studies, the classifications in the SFR are made by an unselected group of mostly inexperienced classifiers. The results indicate that the fracture classification in a national quality register can be accurate enough to permit the evaluation of fracture treatment in specific groups of fractures.
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| 9. |
- Pujari-Palmer, Michael, et al.
(författare)
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Factors That Determine the Adhesive Strength in a Bioinspired Bone Tissue Adhesive
- 2020
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Ingår i: ChemEngineering. - : MDPI AG. - 2305-7084. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Phosphoserine-modified cements (PMCs) are a family of wet-field tissue adhesives that bond strongly to bone and biomaterials. The present study evaluated variations in the adhesive strength using a scatter plot, failure mode, and a regression analysis of eleven factors. All single-factor, continuous-variable correlations were poor (R2 < 0.25). The linear regression model explained 31.6% of variation in adhesive strength (R2 = 0.316 p < 0.001), with bond thickness predicting an 8.5% reduction in strength per 100 μm increase. Interestingly, PMC adhesive strength was insensitive to surface roughness (Sa 1.27–2.17 μm) and the unevenness (skew) of the adhesive bond (p > 0.167, 0.171, ANOVA). Bone glued in conditions mimicking the operating theatre (e.g., the rapid fixation and minimal fixation force in fluids) produced comparable adhesive strength in laboratory conditions (2.44 vs. 1.96 MPa, p > 0.986). The failure mode correlated strongly with the adhesive strength; low strength PMCs (<1 MPa) failed cohesively, while high strength (>2 MPa) PMCs failed adhesively. Failure occurred at the interface between the amorphous surface layer and the PMC bulk. PMC bonding is sufficient for clinical application, allowing for a wide tolerance in performance conditions while maintaining a minimal bond strength of 1.5–2 MPa to cortical bone and metal surfaces.
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