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Biomedical subjects

C R Hutchison

Publications and source records attributed to C R Hutchison.

11 recordsLinked to original sources

Osteochondral defects of the talus treated with fresh osteochondral allograft transplantation.

Between 1980 and 1996, 9 patients with osteocartilagenous lesions of the talus were treated surgically using fresh osteochondral allograft transplantation. In 8 cases the reason for surgery was osteochondritis dissecans (4 of these cases had a previous traumatic injury). In 1 case a fresh osteochondral allograft of the talus was required following a traumatic open fracture of the talus sustained in a motor vehicle accident. Of these 9 grafts, 6 grafts remain in situ with a mean survival of 11 years (range 4 to 19). In the three cases requiring fusion the reason for surgery was not related to arthritic deterioration but due to resorption and fragmentation of the graft.

Adult↗

Proximal femoral allografts for reconstruction of bone stock in revision arthroplasty of the hip. A nine to fifteen-year follow-up.

BACKGROUND: Revision of a femoral component in a patient who has severe bone loss is a complex problem that is likely to increase with the increasing numbers of patients who have multiple revision hip arthroplasties. A valuable option in such a situation is use of a long-stem prosthesis that is cemented to a proximal femoral allograft but not to the host bone. METHODS: Between April 1984 and December 1989, sixty-three total hip arthroplasties in sixty consecutive patients were revised with a proximal femoral allograft-prosthesis construct. The average length of the allograft was 15 cm. The average age of the patients at the time of the revision was 62.5 years. All patients had undergone at least one previous total hip arthroplasty, and an average of 3.8 previous total hip arthroplasties had been performed in the series. Each patient was assigned a modified Harris hip score. Radiographs were examined for trochanteric union, allograft-host union, endosteal and periosteal resorption, component loosening, and fracture. RESULTS: At an average of eleven years (range, nine years and four months to fifteen years) after the revision, forty-five patients were alive, fourteen patients had died, and one patient had been lost to follow-up. The patients who had died or had been lost to follow-up had had a total of fifteen allografts (24%) and had been followed for an average of five years and seven months (range, two years and four months to eight years). The average preoperative Harris hip score for the sixty-three hips was 30 points (range, 6 to 65 points). At the latest follow-up evaluation, the average score for the hips with the original graft in situ was 71 points (range, 47 to 95 points). Five hips failed because of infection, and four of them were successfully revised. Three hips failed because of aseptic loosening, at an average of ten years and three months; two were successfully revised, and the third was awaiting revision at the time of writing. An additional operation was performed in three hips with allograft-host nonunion and in two with dislocation. Success was defined as a postoperative increase in the Harris hip score of greater than 20 points, a stable implant, and no need for additional surgery related to the allograft at the time of the review. The success rate for all hips was 78% (forty-nine of sixty-three) after an average of nine years of follow-up. The success rate for the patients who were alive at the time of follow-up was 77% (thirty-seven of forty-eight hips) after an average of eleven years of follow-up. CONCLUSIONS: The clinical and radiographic results at an average of eleven years after revision hip arthroplasty with a proximal femoral allograft are encouraging. This report represents our early experience; improvements in the technique have been made. We believe that this technique provides a viable option for treatment of the difficult problem of severe femoral bone loss.

Adult↗

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.

Analysis of Variance↗

Complications of total hip arthroplasty: MR imaging-initial experience.

PURPOSE: To investigate the use of standard magnetic resonance (MR) imaging sequences with simple parameter modifications for the detection and characterization of total hip arthroplasty (THA) complications. MATERIALS AND METHODS: An initial phantom study was performed with cobalt-chrome and titanium prostheses to establish the imaging parameters for a subsequent clinical study. In the clinical study, coronal and transverse MR imaging of 14 THA prostheses was performed before and after intravenous contrast material administration in 12 patients who were being considered for revision arthroplasty. The images were reviewed for evidence of juxtaarticular or periprosthetic abnormalities, patterns of contrast enhancement, and quality of periprosthetic tissue depiction. RESULTS: Phantom study results showed improved periprosthetic tissue depiction with use of thin sections, increased frequency-encoding gradient strength, and fast spin-echo sequences. The clinical study results demonstrated periprosthetic abnormalities in 11 cases: mechanical loosening in two cases (including one case with an associated periprosthetic fracture); granulomatosis, eight; and infection, one. In 100% of cases, tissue depiction around the femoral component was judged to be of "diagnostic quality." Tissue depiction around the acetabular component was of diagnostic quality in five (36%) cases. In all seven surgically confirmed cases, a correct diagnosis was made preoperatively with MR imaging. CONCLUSION: By using simple modifications to standard MR imaging sequences, diagnostic-quality MR imaging of THA complications can be performed, particularly around the femoral prosthetic stem.

Acetabulum↗

A needs assessment of surgical residents as teachers.

OBJECTIVE: To determine the needs of surgical residents as teachers of clinical clerks. DESIGN: A needs assessment survey. SETTING: Department of Surgery, University of Toronto. PARTICIPANTS: Clinical clerks and surgical residents and staff surgeons. METHODS: Three stakeholder groups were defined: staff surgeons, surgical residents and clinical clerks. Focus-group sessions using the nominal group technique identified key issues from the perspectives of clerks and residents. Resulting information was used to develop needs assessment surveys, which were administered to 170 clinical clerks and 190 surgical residents. Faculty viewpoints were assessed with semi-structured interviews. Triangulation of these 3 data sources provided a balanced approach to identifying the needs of surgical residents as teachers. RESULTS: Response rates were 64% for clinical clerks and 66% for surgical residents. Five staff surgeons were interviewed. Consensus was noted among the stakeholder groups regarding the importance of staff surgeon role modelling and feedback, resident attitude, time management, knowledge of clerks' formal learning objectives, and appropriate times and locations for teaching. Discrepancies included a significant difference in opinion regarding the residents' capacity to address clerks' individual learning needs and to foster good team relationships. Residents indicated that they did not receive regular feedback regarding their teaching and that staff did not place an emphasis on their teaching role. CONCLUSIONS: This study has, from a multi-source perspective, assessed the needs of surgical residents as teachers. These needs include enhancing residents' education regarding how and what to teach medical students on a surgical rotation, and a need for staff surgeons to increase feedback to residents regarding their teaching.

Clinical Clerkship↗

Proximal femoral allografts for reconstruction of bone stock in revision arthroplasty of the hip.

Full circumferential bone loss of the proximal femur can be managed by segmental allografts. The use of these grafts is indicated for uncontained defects longer than five cm in length. The femoral implant is cemented into the allograft but not into the host. The allograft host junction is stabilized by a step cut or oblique osteotomy and autografted with residual host femur. The results at five and nine years support this kind of reconstruction as a good alternative for this difficult problem.

Arthroplasty, Replacement, Hip↗

Proximal femoral allografts for reconstruction of bone stock in revision arthroplasty of the hip.

Proximal femoral allografts have been used to restore uncontained circumferential defects of the multiply revised total hip arthroplasty. These grafts are used with long stem components that are cemented to the graft but not the host. The junction of host and graft is stabilized by the stem and a step cut with cerclage wires. Autograft bone is placed at the junctions to induce union. Full weightbearing is delayed until union occurs between the graft and the host femur, usually by 3 months. One hundred sixty-eight structural femoral allografts were done; average followup was 4.8 years as of January 1, 1995. Success was defined as an increase in the clinical score of at least 20 points, a stable implant, and no need for further surgery related to the allograft. The success rate in 130 patients with at least 2 years followup is 85%. There have been 17 revisions in 16 patients: 3 revisions for infection, 8 for dislocation, 5 for nonunion, and 1 for pain. The revision rate is 10.1%. Radiographic analysis showed 7 nonunions, minor resorption in 6 patients, and significant resorption in 1 patient. All implants are stable with no lucent lines. The results support using this technique for full circumferential segmental proximal femoral defects in revision hip arthroplasty.

Activities of Daily Living↗