Faculty Bibliography

BACKGROUND: The purpose of this study was to determine when patients recover the ability to safely operate the brakes of an automobile following operative repair of an ankle fracture. METHODS: A computerized driving simulator was developed and tested. Eleven healthy volunteers were tested once to establish normal mean values (Group I), and a group of thirty-one volunteers with a fracture of the right ankle were tested at six, nine, and twelve weeks following operative repair (Group II). The subjects were tested with a series of driving scenarios (city, suburban, and highway). Scores on the Short Form Musculoskeletal Assessment were recorded at six, nine, and twelve weeks and were compared with the results of the driving test. We investigated the effect of the time of the visit and of the testing condition on the braking times. RESULTS: The total braking time was 1079 msec for Group I and 1330, 1172, and 1160 msec for Group II at six, nine, and twelve weeks, respectively, postoperatively (p = 0.0094). The total braking time consistently improved for each of the driving scenarios at each successive data point (p = 0.05). The increase in the total braking time at six weeks meant an increase in the distance traveled by the automobile before braking of 22 ft (6.7 m) at 60 mph (96.6 km/hr), and the increase at nine weeks meant an increase of 8 ft (2.4 m) at 60 mph. The functional outcome improved at each successive visit, although no significant association was found between the functional scores and normalization of total braking time. CONCLUSION: By nine weeks, the total braking time of patients who have undergone fixation of a displaced right ankle fracture returns to the normal, baseline value

Background. More than 20 studies have investigated the relation between meat and dairy consumption and breast cancer risk with conflicting results. Our objective was evaluate the risk of assess whether non-dietary risk factors modify the relation. studies from North America and Western Europe with at least 200 intakes, and a validation study of dietary assessment instrument. diagnosed with invasive breast cancer during to 15 year of intakes of total meat, red me white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categor analyses suggested a J-shaped association for egg consumption where, comp to women who did not eat eggs, breast cancer risk was slightly decreased am women who consumed <2 eggs per week but slightly increased among women who consumed >=1 egg per day. Conclusions. We produ and risk of breast cancer. An inconsistent relation between egg consumption risk of breast cancer merits further investigation

OBJECTIVE: To determine the effect of admission hemoglobin level on patient outcome after hip fracture. STUDY DESIGN: Prospective, consecutive. PATIENTS: From July 1991 to June 1997, 395 community-dwelling patients sixty-five years of age or older who had sustained an operatively treated femoral neck or intertrochanteric fracture were prospectively followed up. MAIN OUTCOME MEASUREMENTS: Postoperative complications, in-hospital mortality rate, hospital length of stay, hospital discharge status, place of residence at one year, and mortality and recovery of ambulatory ability and activities of daily living status at three, six, and twelve months. RESULTS: Women with admission hemoglobin levels below 12.0 grams per deciliter and men with admission hemoglobin levels below 13.0 grams per deciliter were classified as anemic. One hundred eighty patients (45.6 percent) were considered anemic on admission. Patients who were anemic were more likely to have an American Society of Anesthesiologists rating of III or IV and have sustained an intertrochanteric fracture. Hospital length of stay and mortality rate at six and twelve months were significantly higher for patients who were anemic on admission. There were no differences in the incidence of postoperative complications, hospital discharge status, place of residence at one year, in-hospital mortality rate, and three-month mortality rate between patients who were and were not anemic on admission. In addition, there were no differences in the recovery of ambulatory ability and of basic and instrumental activities of daily living status at three, six, and twelve months between the two patient groups. CONCLUSIONS: Patients at risk for poor outcomes after hip fracture can be identified by assessing hemoglobin levels at hospital admission

BACKGROUND: This study compared the fixation stability of two treatments for humeral shaft fractures with segmental bone loss during cyclic, physiologic loading. METHODS: Six matched pairs of human humeri received either a 10-hole broad dynamic compression plate or a locked antegrade inserted humeral nail applied to a humeral diaphyseal osteotomy with a 1.5-cm gap defect. The bone-implant humeral constructs were axially loaded for 10,000 cycles at 250 N and 500 N, with measurements of gap displacement and calculation of construct stiffness. The specimens were then loaded to failure. RESULTS: Cyclic loading showed no difference between the two groups for average gap displacement or construct stiffness. The intramedullary nail constructs failed by humeral shaft splitting (n = 4) or head cut-out (n = 2) at an average of 958.3 N, whereas the plate constructs failed by humeral shaft splitting and screw pull-out (n = 3) or plate bending (n = 3) at an average of 641.7 N (p < 0.001). CONCLUSION: Although both methods offer similar fixation stability under physiologic loads, the higher load to failure demonstrated by intramedullary nail fixation may have implications for the patient with multiple injuries for whom partial weightbearing on the injured upper extremity may be necessary

Simulated supracondylar fractures were created proximal to posterior cruciate ligament-retaining total knee arthroplasty components in paired human cadaver femora and stabilized with either a retrograde-inserted locked supracondylar nail or the Less Invasive Stabilization System (LISS; Synthes USA, Paoli, PA). Loads were applied to create bending and torsional moments on the simulated fracture stabilized with either no gap or a 10-mm gap. The LISS exhibited less torsional stability with anterior (P<.001) and posterior loads (P<.01). When varus loads were applied to 10-mm-gap specimens, the specimens stabilized with a retrograde nail had an 83% reduction in fracture displacement (P<.001) and 80% less medial translation of the distal fragment (P<.001). The samples stabilized with the LISS had a 93% reduction in fracture gap displacement when a valgus load was applied with a 10-mm gap (P<.001). Overall, these results suggest that the retrograde-inserted nail may provide greater stability for the management of periprosthetic supracondylar femur fractures in patients with a posterior cruciate ligament-retaining femoral total knee arthroplasty component

OBJECTIVE: To determine the relative stability of three fixation methods for displaced capitellum fractures. DESIGN: Twelve matched pairs of embalmed humeri were divided into two equal groups and simulated capitellum fractures created. The first group compared cancellous lag screws placed in an anteroposterior direction to screws placed in the posteroanterior direction. The second group compared the Acutrac compression screw, inserted anteroposteriorly, to the more stable construct from the first test group. METHODS: All specimens were cyclically tested with simulated physiologic loading. Both displacement of the capitellum over a range of cycles and the number of cycles to failure were recorded. RESULTS: Fixation with posteroanteriorly directed cancellous lag screws was significantly more stable than anteroposteriorly directed screws at 2000 cycles (p = 0.007); loads to failure were not statistically different. Fixation by the Acutrac screws was significantly more stable than posteroanterior cancellous screws at 2000 cycles (p = 0.03). The Acutrac fixation had a higher failure load; however, this was not statistically significant. CONCLUSION: The headless screws tested in this biomechanical study provided more stable fixation of capitellum fractures in the cadaveric specimens than four-millimeter partially threaded cancellous lag screws and may do so in the clinical setting. When the cancellous lag screws were tested, insertion in the posteroanterior direction provided more stable fixation than the anteroposterior direction and has clinical benefit of not violating the articular surface. Ultimately, the decision of which method to use lies with the attending surgeon and the technique with which he or she feels most comfortable