Faculty Bibliography

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

Fat embolization and the clinical syndrome associated with this pathology are poorly understood complications of skeletal trauma. Fat embolization is characterized by release of fat droplets into systemic circulation after a traumatic event. Fat embolism syndrome (FES) is an infrequent clinical consequence of fat embolization. Classically, FES presents with the triad of pulmonary distress, mental status changes, and petechial rash 24 to 48 hours after pelvic or long-bone fracture. FES incidence increases with the number of fractures sustained by an individual. Many clinicians believe that FES incidence has decreased over the past several decades secondary to advances in resuscitative measures. FES pathophysiology remains unclear. Current theories involve common mechanical and biochemical mechanisms that explain how fat emboli manifest as FES. Much controversy surrounds the question of whether there is a causal relation between intramedullary nailing and FES onset. Clinical diagnosis is essential, as laboratory and radiographic findings are nonspecific. Early supportive pulmonary therapy and other resuscitative measures may halt the pathophysiologic cascade and prevent clinical deterioration. Fortunately, if FES is diagnosed early, and pulmonary and cardiac functions are optimally supported, prognosis is very good

BACKGROUND: Displaced ipsilateral fractures of the clavicle and the glenoid neck are a complex injury pattern that is usually the result of high-energy trauma. The treatment of these injuries is controversial, as good results have been reported with both operative and nonoperative treatment. METHODS: Nineteen patients who had sustained a displaced fracture of the glenoid neck with an ipsilateral clavicular fracture or acromioclavicular separation (floating shoulder) were retrospectively evaluated. The treatment was nonoperative in twelve patients and operative in seven. At the time of final follow-up, standard radiographs were made and all patients were examined by a physical therapist and either a fellowship-trained shoulder surgeon or an orthopaedic traumatologist. In addition, each patient responded to three different validated objective functional outcome measures: the Short Form-36, the American Shoulder and Elbow Surgeons Shoulder Scale, and the Disabilities of the Arm, Shoulder and Hand Questionnaire. Isokinetic strength-testing was performed, and strength in internal and external rotation was compared with that of the uninvolved shoulder. The main outcome measures included fracture-healing, functional outcome, patient satisfaction, and muscular strength. RESULTS: With regard to range of motion, only the amount of forward flexion was found to be significantly greater in the operatively treated group (p = 0.03). The operatively treated shoulders were found to be weaker in external rotation at 300 degrees /sec and weaker in internal rotation at 180 degrees /sec. When normalized to hand dominance, however, the numbers were too small to identify any significant difference. There was no significant difference between groups with regard to the three functional outcome measures. CONCLUSIONS: Good results may be seen both with and without operative treatment. Therefore, we cannot universally recommend operative treatment for a double disruption of the superior suspensory shoulder complex. Treatment must be individualized for each patient