Deformation and recovery of cartilage in the intact hip under physiological loads using 7T MRI.

UNLABELLED: Accurate measurement of cartilage deformation in loaded cadaver hip joints could be a valuable tool to answer clinically relevant research questions. MRI is a promising tool, but its use requires an understanding of cartilage deformation and recovery properties in the intact hip. Our objective was to answer the following questions: (1) How long does it take for hip cartilage to reach a deformed steady-state thickness distribution under simulated physiological load, and how much does the cartilage deform? (2) How long does it take for hip cartilage to return to the original cartilage thickness distribution once the load is removed? METHODS: Five human hip specimens were axially loaded to 1980N in a 7T MR scanner and scanned every 15min throughout loading. One specimen was scanned every hour throughout recovery from load. One repeatability specimen was loaded and scanned every day for 4 days. Hip cartilage was segmented as a single unit and thickness was measured radially. RESULTS: The hip cartilage reached a steady-state thickness distribution after 225min of load, and 16.5h of recovery. Mean strain after 225min of load was 30.9%. The repeatability specimen showed an average day-to-day change in mean cartilage thickness of 0.10mm over 4 days of data collection. The amount of deformation (0.96mm) was far greater than the image resolution (0.11mm) and error due to repeatability (0.10mm). CONCLUSION: Using an ex vivo model, this method has potential for assessing changes in hip cartilage strain due to injury or surgical intervention.

Evaluating surgical resident selection procedures.

PURPOSE: The purposes of this study were to develop and assess a rating form for selection of surgical residents, determine the criteria most important in selection, determine the reliability of the assessment form and process both within and across sites, and document differences in procedure and structure of resident selection processes across Canada. METHODS: Twelve of 13 English-speaking orthopedic surgery training programs in Canada participated during the 1999 selection year. The critical incident technique was utilized to determine the criteria most important in selection. From these criteria a 10-item rating form was developed with each item on a 5-point scale. Sixty-six candidates were invited for interviews across the country. Each interviewer completed one assessment form for each candidate, and independently ranked all candidates at the conclusion of all interviews. Consensus final rank orders were then created for each residency program. Across all programs, pairwise program-by-program correlations for each assessment parameter were made. RESULTS: The internal consistency of assessment form ratings for each interviewer was moderately high (mean Cronbach's alpha = 0.71). A correlation between each item and the final rank order for each program revealed that the items work ethic, interpersonal qualities, orthopedic experience, and enthusiasm correlated most highly with final candidate rank orders (r = 0.5, 0.48, 0.48, 0.45, respectively). The interrater reliabilities (within panels) and interpanel reliabilities (within programs) for the rank orders were 0.67 and 0.63, respectively. Using the Spearman-Brown prophecy formula, it was found that two panels with two interviewers on each panel are required to obtain a stable measure of a given candidate (reliabilities of 0.80). The average pairwise program-by-program correlations were low for the final candidate rank orders (0.14). CONCLUSIONS: A method was introduced to develop a standard, reliable candidate assessment form to evaluate residency selection procedures. The assessment form ratings were found to be consistent within interviewers. Candidate assessments within programs (both between interviewers and between panels) were moderately reliable suggesting agreement within programs regarding the relative quality of candidates, but there was very little agreement across programs.

A computer-based trauma simulator for teaching trauma management skills.

BACKGROUND: The management of multiply injured trauma patients is a skill requiring broad knowledge, sound judgment, and leadership capabilities. The purpose of this study was to evaluate the effectiveness of a computer-based trauma simulator as a teaching tool for senior medical students. METHODS: All year-4 clinical clerks at the University of Toronto were approached to participate in a focused, 2-hour trauma management course. The volunteer rate for the course was 79%. Students were randomized to either computer-based simulator or seminar-based teaching groups. Outcome measures in this study were students' trauma objective structured clinical examination (OSCE) scores. RESULTS: Both the trauma simulator and seminar teaching groups performed significantly better than the comparison group (no additional teaching) on the trauma OSCE patient encounter component, but not the written component of the examination. There was no significant difference in the performances of the trauma simulator and seminar teaching groups. Students overwhelmingly felt the trauma simulator was effective for their trauma teaching, and improved their overall confidence in clinical trauma scenarios. CONCLUSIONS: There is a significant benefit associated with a focused, clinically based trauma management course for senior medical students. No additional improvement was noted with the use of a high fidelity computer-based trauma simulator.

Anterior tibial compartment pressures during intermittent sequential pneumatic compression therapy.

We studied the anterior tibial compartment pressures during the application of a JOBST sequential intermittent pneumatic compression device on 5 healthy human volunteers (10 legs). Intracompartmental pressures were measured using a slit catheter. The measurements of interstitial pressures were highest at maximal calf inflation, and pressures were increased for approximately 120 seconds during each cycle. Pressure measurements in the inflated pressure sleeve varied less than 10% with the measured anterior tibial compartment pressures during intermittent pneumatic compression therapy. This intermittent pneumatic compression device may elevate intramuscular pressure significantly above that necessary to render muscle ischemic. However, these periods of pressure elevation are not long enough to produce any significant adverse effects, and the beneficial effects of decreased edema fluid may be safely realized.

Surgery of the hand in severe systemic sclerosis.

Ten patients with scleroderma and severe hand problems required surgery, and seven were available for follow-up (two died from scleroderma-related complications and one was lost to follow-up). The mean duration of follow-up was 4 (range 1.5-9) years. Thirty-three procedures were carried out, including five metacarpophalangeal joint excisional arthroplasties, 13 proximal interphalangeal joint fusions, ten distal interphalangeal joint fusions, and one thumb interphalangeal joint fusion. The metacarpophalangeal joint excision arthroplasties and proximal interphalangeal joint fusions were performed for the correction of severe fixed "finger-in-palm" deformities. Lesions of cutaneous calcinosis were removed in four patients. Fixation was satisfactory in all cases of interphalangeal joint fusion, with no cases of nonunion. Wound healing was satisfactory in six of seven patients. A second surgical procedure was required in three patients for the removal of tension band wires following interphalangeal fusion. Calcinosis was effectively removed using a high-speed dental burr. The results of hand surgery for systemic sclerosis are reliable, but goals must be limited and patient expectations should be modest.

Chronic pain following ankle sprains in athletes: the role of arthroscopic surgery.

We reviewed 100 patients treated arthroscopically for symptoms of chronic ankle pain associated with sprains of the ankle. All had pain that had failed to respond to conservative treatment for at least 6 months. The pathology in 95 of the 100 ankles studied could be categorized into one of three groups: the instabilities (lateral and syndesmotic), the impingements (anterior and anterolateral), and articular lesions (chondral and osteochondral). Five patients had nonspecific osteoarthritis and/or synovitis on arthroscopy. Patients were followed-up for improvements in six categories: pain, swelling, stiffness, limping, activity, and instability. The primary outcomes of pain and activity were analyzed statistically. Patient satisfaction and return to sports were evaluated. Significant improvements were obtained for patients treated for syndesmotic instability, and anterior and anterolateral impingement. Chondral fractures in the presence of a stable ankle had good results in 75% of cases, compared with those in unstable ankles with only 33% good results. Osteochondritis dissecans was treated successfully by excision of the lesion and abrasion of the base. Patients with chronic lateral instability were treated by open repair, so only the diagnostic arthroscopic findings are reported. We concluded that arthroscopy offered little to the management of lateral instability unless there was considerable doubt regarding the diagnosis. There were minimal improvements for the patients with nonspecific diagnoses such as posttraumatic synovitis. Ankle arthroscopy may be a very useful diagnostic and therapeutic tool in patients who have not responded to conservative therapy.