The accuracy and precision of radiostereometric analysis in monitoring tibial plateau fractures

Background and purpose: The application of radiostereometric analysis (RSA) to monitor stability of tibial plateau fractures during healing is both limited and yet to be validated. We therefore evaluated the accuracy and precision of RSA in a tibial plateau fracture model. Methods: Combinations of 3, 6, and 9 markers in a lateral condyle fracture were evaluated with reference to 6 proximal tibial arrangements. Translation and rotation accuracy was assessed with displacement-controlled stages, while precision was assessed with dynamic double examinations. A comparison of error according to marker number and arrangement was completed with 2-way ANOVA models. Results: The results were improved using more tantalum markers in each segment. In the fracture fragment, marker scatter in all axes was achieved by a circumferential arrangement (medial, anterior, and lateral) of the tantalum markers above the fixation devices. Markers placed on either side of the tibial tuberosity and in the medial aspect of the fracture split represented the proximal tibial reference segment best. Using 6 markers with this distribution in each segment, the translation accuracy (root mean square error) was less than 37 μm in all axes. The precision (95% confidence interval) was less than ± 16 μm in all axes in vitro. Rotation, tested around the x-axis, had an accuracy of less than 0.123° and a precision of ± 0.024°. Interpretation: RSA is highly accurate and precise in the assessment of lateral tibial plateau fracture fragment movement. The validation of our center's RSA system provides evidence to support future clinical RSA fracture studies.Lucian B Solomon, Aaron W Stevenson, Stuart A Callary, Thomas R Sullivan, Donald W Howie, and Mellick J Chehad

Journal Scan: Highlights of Australian Orthopaedics

The original publication can be found at www.springerlink.comMellick J. Chehad

Testing the Hip Abductor Muscle Strength of Older Persons Using a Handheld Dynamometer

Objective: To investigate the reliability of a clinically applicable method of dynamometry to assess and monitor hip abductor muscle strength in older persons. Design: Bilateral isometric hip abductor muscle strength measured with a handheld dynamometer, patients supine with the contralateral hip positioned directly against a wall for stabilization. Reliability determined by comparing intra-assessor and inter-assessor results and comparison to a criterion standard (stabilized dynamometer with patients in the standing position). Setting: UniSA Nutritional Physiology Research Centre. Participants: Twenty-one patients older than 65 years were recruited from the Royal Adelaide Hospital. Main Outcome Measures: Intraclass correlation coefficients (ICCs), bias, and limits of agreement calculated to determine reliability. Results: Intra-assessor and inter-assessor ICCs were high (0.94 and 0.92-0.94, respectively). There was no intra-assessor bias and narrow limits of agreement (±2.4%). There was a small inter-assessor bias but narrow limits of agreement (0.6%-0.9% and ± 2.3%, respectively). There was a wide variation comparing results to the criterion standard (±5.0%-5.2% limits of agreement), highlighting problems attributed to difficulties that the test population had with the standing position used in the criterion standard test. Conclusions: Testing older persons’ hip abductor muscle strength while in the supine position with optimal pelvic stabilization using a handheld dynamometer is highly reliable. While further studies must be done to assess patients with specific pathologies, this test has potential application to monitor and evaluate the effects of surgical interventions and/or rehabilitation protocols for a variety of conditions affecting hip abductor function such as hip fractures and arthritis

Surgical education and training in Australia and New Zealand

Surgical education for medical students in Australia and New Zealand is provided by 19 universities in Australia and 2 in New Zealand. One surgical college is responsible for managing the education, training, assessment, and professional development programs for surgeons throughout both countries. The specialist surgical associations and societies act as agents of the college in the delivery of these programs, the extent of which varies among specialties. Historically, surgical training was divided into basic and specialist components with selection required for each part. In response to a number of factors, a new surgical education and training program has been developed. The new program incorporates a single merit-based national selection directly into the candidate's specialty of choice. The existing curriculum for each of the nine specialties has been remodeled to a competence-based format in line with the competence required to undertake the essential roles of a surgeon. New standards and criteria have been produced for accreditation of health care facilities used for training. A new basic surgical skills education and training course has been developed, with simulation playing an increasing role in all courses. Trainees' progress is assessed by workplace-based assessment and formal examinations, including an exit examination. The sustained production of sufficient competent surgeons to meet societal needs encompasses many challenges including the recruitment of appropriate graduates and the availability of adequate educational and clinical resources to train them. Competence-based training is an attractive educational philosophy, but its implementation has brought its own set of issues, many of which have yet to be resolved.John P. Collins, Ian D. Civil, Michael Sugrue, Zsolt Balogh, Mellick J. Chehad

Differentially Loaded Radiostereometric Analysis to Monitor Fracture Stiffness: A Feasibility Study

Inability to accurately and objectively assess the mechanical properties of healing fractures in vivo hampers clinical fracture management and research. We describe a method to monitor fracture stiffness during healing in a clinical research setting by detecting changes in fracture displacement using radiostereometric analysis and simultaneously measuring applied axial loads. A method was developed for load application, positioning of the patient, and radiographic setup to establish the technique of differentially loaded radiostereometric analysis (DLRSA). A DLRSA examination consists of radiostereometric analysis radiographs taken without load (preload), under different increments of load, and without load (postload). Six patients with distal femur fractures had DLRSA examinations at 6, 12, 18, and 26 weeks postoperatively. The DLRSA method was feasible in a clinical setting. The method provides objective and quantifiable data for internally fixed fractures and may be used in clinical research as a tool to monitor the in vivo stiffness of healing femoral fractures managed with nonrigid internal fixation