Faculty Bibliography

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

In this article, we briefly mention the personal, social, and economic costs of gunshot injuries; describe the science of ballistics and how differences in ballistics affect gunshot wounds and their treatment; and review the general principles involved in managing gunshot injuries. We will summarize the strategies for treating adults with gunshot injuries to specific regions of the lower extremities--the hip, the femur, the knee, the tibia, and the foot

OBJECTIVE: To determine the biomechanical characteristics of four different fixation constructs for split depression fractures of the lateral tibial plateau (OTA classification 41B3.1). DESIGN: Laboratory investigation using a cadaveric simulated split depression tibial plateau fracture model. SETTING: Split depression tibial plateau fractures were created, reduced, and instrumented in a matched pair design. Specimens were tested for stiffness using a materials testing machine. INTERVENTION: Tibias were instrumented with an L-buttress plate, four 3.5-millimeter subchondral raft screws with an antiglide plate, an L-buttress plate with cancellous allograft, or four 3.5-millimeter subchondral raft screws placed through a periarticular plate. MAIN OUTCOME MEASUREMENTS: Vertical subsidence of the lateral tibial plateau was measured for the entire construct and for the local depression. The relative medial and lateral condylar tilt with central loading was also measured. RESULTS: There was no significant difference between the four fixation methods for overall longitudinal stiffness of the proximal tibial fracture fixation construct (range, 2,026 to 2,666 newtons per millimeter). The local depression stiffness for the raft-periarticular plate and raft-antiglide plate were 425 newtons per millimeter and 342 newtons per millimeter, respectively, versus 243 newtons per millimeter and 210 newtons per millimeter for the two large fragment buttress constructs. There was no significant difference between the local depression stiffness for the two raft constructs. There was no significant difference between the local depression stiffness for the two buttress plate constructs. Local depression stiffness was found to be significantly greater for the raft-periarticular plate construct when compared with the large fragment buttress plate construct without bone graft (p = 0.0314). Condylar tilt data showed a significant difference between the medial tilt observed in the prefracture specimen and the lateral tilt observed after fixation (p less-than-or-equal 0.017) for all constructs. CONCLUSIONS: There was no significant difference in the overall construct stiffness between the four fixation constructs. Fixation constructs with a raft of subchondral screws were more resistant to local depression loads. This supports the use of a raft construct when a central depression is a significant component of the overall fracture pattern. Condylar tilt data showed a persistent weakness in the postfixation lateral plateau regardless of fixation construct when compared with the intact specimen. This supports the current clinical practice of delayed weight-bearing for ten to twelve weeks

This study was designed to determine whether delayed reduction of physeal fractures in an animal model causes growth disturbance, and whether final alignment is better in delayed or malreduced fractures. Salter 1 fractures of the proximal tibia were created in 41 immature rats randomized into five groups. The fractures were reduced as follows: group 1, immediately; group 2, 6 hours; group 3, 24 hours; group 4, 48 hours; and group 5, left malreduced. Both legs were analyzed for leg-length discrepancy, angular deformity, and evidence of radiographic bar. No radiographic physeal bar or leg-length discrepancy was seen among any of the groups. Angular deformity was greatest in group 5 and least in group 1. Immediate reduction resulted in the least angular deformity. Delayed reduction showed no evidence of physeal damage, physeal growth disturbance, or radiographic bar formation. Alignment was not improved in delayed reduction versus malreduced fractures

The relative stiffness of five different external wrist fixators currently in use for distal radius fractures was determined using a uniform fracture model consisting of wood dowels to isolate the effects of the fixators themselves. Each construct was loaded in axial compression, eccentric and cantilever modes of bending, and torsion. The stiffest of the fixators varied by a factor of three in compression, five in bending, and three in torsion. Although the ideal stiffness of a wrist fixator is unknown, there is a large variation in the stiffness of existing devices