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- 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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| 2. |
- Hussey, Daniel K, et al.
(författare)
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Scoring the Current Risk Stratification Guidelines in Follow-up Evaluation of Patients After Metal-on-Metal Hip Arthroplasty: A Proposal for a Metal-on-Metal Risk Score Supporting Clinical Decision-Making.
- 2016
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Ingår i: The Journal of bone and joint surgery. American volume. - 1535-1386. ; 98:22, s. 1905-1912
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Tidskriftsartikel (refereegranskat)abstract
- In the follow-up evaluation of patients with metal-on-metal (MoM) hip replacements, current evidence suggests that orthopaedic surgeons should avoid reliance on any single investigative tool. Current risk stratification guidelines can be difficult to interpret because they do not provide guidance when there are several risk factors in different groups (high and low risk). To improve the clinical utility of risk stratification guidelines, we designed a scoring system to assess the risk of revision.The study population consisted of 1,709 patients (1,912 hips) enrolled in a multicenter follow-up study of a recalled MoM hip replacement. Eleven scoring criteria were determined on the basis of existing follow-up algorithm recommendations and consisted of patient-related factors, symptoms, clinical status, implant type, metal ion levels, and radiographic imaging results. Forward stepwise logistic regression was conducted to determine the minimum set of predictive variables for the risk of revision and to assign variable weights. The MoM risk score for each hip was then created by averaging the weighted values of each predictive variable.Receiver operating characteristic curve analysis yielded good discrimination between all revised and unrevised hips, with an area under the curve of 0.82 (p < 0.001). The odds of revision for the group with a high MoM risk score were increased by 5.8-fold (95% confidence interval [CI], 3.1 to 11.0) relative to the moderate risk group and by 21.8-fold (95% CI, 9.9 to 48.0) compared with the low risk group.Although the use of MoM hip arthroplasty has been limited since 2010, we continue to be faced with the follow-up and risk assessment of thousands of patients who have not had a revision. As more knowledge about risk stratification is gained, the complexity of the algorithms is expected to increase. We propose the use of the MoM risk score as a tool to aid in the clinical decision-making process.Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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