Effect of articular step-off and meniscectomy on joint alignment and contact pressures for fractures of the lateral tibial plateau.

OBJECTIVES: To determine the effects of intraarticular step-off and lateral meniscectomy on the alignment of the articular axis, contact area, and pressures for lateral tibial plateau fractures. DESIGN: Biomechanical cadaver study. INTERVENTION: Six fresh cadaveric knees were used. A simulated split fracture of the lateral tibial plateau was reproducibly created by osteotomies, and articular step-offs of zero, one, two, four, and six millimeters were achieved by using support shims. The knee was loaded with 500 newtons in 0 degrees and 350 newtons in 30 degrees of flexion. A digital camera determined changes in the alignment of the articular axis, and F-Scan sensors were inserted into the medial and lateral joint compartments to determine the pressures and pressure distributions. MAIN OUTCOME MEASUREMENT: Each specimen was tested at step-offs of zero, one, two, four, and six millimeters, with the presence or absence of the lateral meniscus. The changes in alignment of the articular axis, the contact area, and the average and maximum contact pressures for each condyle were obtained. RESULTS: Increased articular step-off heights progressively increased valgus angulation and average and maximum contact pressures and progressively decreased contact areas in lateral compartment. At a six-millimeter step-off with 0 degrees of flexion, the valgus angle increased an average of 7.6 degrees, and average contact pressures and maximum contact pressures increased an average of 208 percent and 97 percent, respectively, and contact area decreased an average of 33 percent (p < 0.05). Meniscectomy increased valgus angles by an average of 38 percent and contact pressures by an average of 45 percent and decreased contact areas by 26 percent in the lateral compartment at the same articular step-off heights (p < 0.05). CONCLUSION: The results of this study show the importance of decreasing articular step-off heights in treating lateral tibial plateau split fractures, particularly if a meniscectomy is performed.

Outcome after hip fracture in individuals ninety years of age and older.

OBJECTIVE: To assess outcome after hip fracture in patients ninety years of age and older, as compared with a population of the same age and sex in the United States and younger patients with hip fractures. DESIGN: Prospective, consecutive. SETTING: University teaching hospital. METHODS: Eight hundred fifty community-dwelling elderly people who sustained an operatively treated hip fracture were prospectively followed up. MAIN OUTCOME MEASUREMENTS: The outcomes examined in this study were the patients' in-hospital mortality and postoperative complication rates, hospital length of stay, discharge status, mortality rate, place of residence, ambulatory ability, and independence in basic and instrumental activities of daily living twelve months after surgery. RESULTS AND CONCLUSIONS: The mean patient age was 79.7 years (range 65 to 105 years). Seventy-six (8.9 percent) patients were ninety years of age and older. Patients who were ninety years of age and older had significantly longer mean hospital lengths of stay than younger individuals (p = 0.01). People ninety years of age and older were more likely to die during the hospital stay (p = 0.001) and within one year of surgery (p = 0.001). Patients who were ninety years of age and older were more likely to have a decrease in their basic activities of daily living status (p = 0.03) and ambulation level (p = 0.01). Younger individuals had a higher standard mortality ratio (1.48) than did patients who were ninety years of age and older (1.24). Being ninety years of age and older was not predictive of having a postoperative complication, of being placed in a skilled nursing facility at discharge or at one-year follow-up, or recovering of prefracture independence in instrumental activities of daily living.

Effect of immediate weightbearing on plated fractures of the humeral shaft.

BACKGROUND: This study evaluated the effect of immediate weightbearing on fractures of the humeral shaft treated with dynamic compression plates. METHODS: Eighty-three fractures met the inclusion criteria. The weightbearing status of the humerus was based on associated injuries and not the fracture pattern. There were no differences between the weightbearing and nonweightbearing groups in patient or fracture demographics. RESULTS: Ninety-four percent of the fractures healed after the initial operation. Two in the nonweightbearing group and three in the weightbearing group required a second operation to achieve union. Alignment did not differ between the two groups. Immediate full weight. bearing had no effect on the union or malunion rate. CONCLUSION: When indicated, open reduction and internal fixation of the diaphysis of the humerus, followed by immediate weightbearing through the involved humerus, is a safe and efficacious procedure.

Open reduction and internal fixation of tibial pilon fractures.

Although it is evident that the fracture of the tibial plafond is a complex, often debilitating injury, its management is not clear. These injuries generally fall into one of two categories. The low-energy, rotational type of fracture has been shown to have excellent clinical and functional results with open reduction and internal fixation. The high-energy, compression type of fracture has had uniformly moderate results and historically high complication rates. Some authors think that bridging external fixation with or without limited internal fixation should be employed in high-energy fractures. Others believe that open reduction and internal fixation to avoid articular incongruence and development of axial malalignment is needed for good long-term outcome. The authors believe the latter. Staging the treatment of the patient can minimize development of soft tissue complications. The authors follow the recommendations of Patterson and Sirkin and believe that high-energy pilon fractures should be temporized with an external fixator with or without fibular plating to restore length. Any open would should be addressed at this time. Definitive fixation should be planned for between 10 and 14 days, by which time the soft tissue envelop is likely to be ready to accept the further insult of surgery. The surgical technique should be well planned for and include the use of meticulous soft tissue techniques and indirect reduction methods. With the proper attention to detail, long-term results will be maximized.

Tibial pilon fractures: a comparison of treatment methods.

OBJECTIVE: This retrospective review of surgically treated distal tibia fractures was undertaken to determine whether treatment with open reduction and internal fixation (ORIF) was more efficacious in achieving fracture union than one of two external fixation methods. METHODS: Of the 60 study patients with pilon fractures, 21 patients were treated with an ankle-spanning half-pin external fixator, 15 patients with a single-ring hybrid external fixator, and 24 patients with ORIF. The severity of injuries was similar across groups. RESULTS: There was no significant difference in complication rates between groups, although two below-knee amputations were required in the ORIF group. A greater (p = 0.03) number of malunions occurred in the fractures treated with external fixation when compared with those treated with ORIF. Fractures in the external fixator groups showed this significant tendency to lose their initial adequate reduction, independent of bone grafting or fibula fixation. There was no significant difference between groups in the need for bone grafting. There was a trend for patients treated with a single ring hybrid frame to require late bone grafting for metaphyseal-diaphyseal nonunion. CONCLUSION: External fixation offers advantages in the treatment of the soft-tissue injury associated with pilon fractures, but malunion continues to be a problem with this method of fixation.

Comparative biomechanics of hybrid external fixation.

OBJECTIVE: To compare the elastic stiffness, in several loading modes, of commercially available hybrid external fixation systems. DESIGN: Laboratory investigation using a polyvinylchloride pipe periarticular tibia fracture model. SETTING: Simulated periarticular fractures were created in an in vitro tibia fracture model. Instrumented specimens and intact controls were elastically tested in a biomaterials testing system. INTERVENTION: Groups of simulated periarticular tibia fractures were stabilized with one of six different hybrid external fixator designs. MAIN OUTCOME MEASUREMENTS: Elastic stiffness of each specimen was measured in compression, torsion, flexion bending, extension bending, and varus/valgus bending. RESULTS: Fixators with multiple levels of fixation in the periarticular fragment, regardless of design, were stiffer than those with one level. Specifically, the EBI Ring Connector fixator was stiffer than all others in all modes of testing. The Ace, Synthes, Smith & Nephew Richards, and How medica fixators were mechanically similar. The Zimmer Torus fixator was the least stiff fixator tested. CONCLUSIONS: Fixators with multiple levels of fixation in the periarticular fragment, regardless of design, were stiffer than those with one level. The choice of which hybrid external fixator to use should be made based not only on stiffness but also on ease of clinical application, patient comfort, customer support from the manufacturer, and cost. Clinical investigation of the efficacy of each of these devices is warranted.

Reamed intramedullary nailing of the femur: 551 cases.

BACKGROUND: The care of the patient with the fractured femur entails a multiple surgical team approach. Healing of the fracture and expediency in the operating room are both important. We sought to determine the results of the treatment of fractures of the femoral shaft with interlocking femoral nails inserted with closed techniques, and to compare the outcomes of fractures nailed by using a fracture table with those stabilized with the leg draped free on a radiolucent table. METHODS: Eight hundred eighty-two consecutive patients with fractures of the femoral shaft treated with a first-generation intramedullary nail at the authors' institution during the years 1986 to 1996 were identified. Five hundred fifty-one fractures in 515 patients met the inclusion criteria. RESULTS: Treatment with an intramedullary nail led to a union rate of 98.9%. There were six infections, all occurring in closed fractures. Thirty-eight percent of the fractures had hardware removed, most commonly because of pain. One nail and 13 locking bolts broke. Four hundred eighteen fractures had adequate radiographs available to assess fracture alignment. No fracture healed with more than 10 degrees of angulation in either plane. Forty-four fractures healed with more than 5 degrees of angulation. A distal third fracture was found to be associated with an increased incidence of malalignment. There were no differences in outcomes between fractures stabilized with or without a fracture table. CONCLUSION: Reamed intramedullary nailing of femoral shaft fractures results in a low rate of nonunion, malunion, infection, and hardware failure. There is no difference in the outcomes of fractures treated with and without the use of a fracture table. This is particularly useful in the patient with multiple injuries for whom transfer to a fracture table may not be time effective.

The biomechanics of hybrid external fixation.

OBJECTIVE: The objective of this study was to ascertain which factors determine the rigidity of a hybrid external fixation frame in a tibial periarticular fracture model. DESIGN: Laboratory investigation using a polyvinylchloride pipe periarticular tibia fracture model. SETTING: Simulated periarticular tibia fractures were created in a tibia model. Instrumented specimens were tested in a biomaterials testing system. INTERVENTION: Groups of simulated periarticular tibia fractures were stabilized with one of nine different external fixation constructs with components from one manufacturer. MAIN OUTCOME MEASUREMENTS: Elastic stiffness was measured for each specimen in compression, torsion, flexion bending, extension bending, and varus and valgus bending. RESULTS: The four-ring Ilizarov fixator was the stiffest in all modes of testing. There was a trend toward increasing stiffness with an increasing number of rings. Fixators constructed with multiple levels of fixation in the periarticular fragment were stiffer in all modes of testing. The additional spacing between wires gained by the use of a single thick carbon ring or the use of a drop wire three centimeters from a single ring did not increase stiffness in this model. Frame modifications intended to augment the bar-to-ring connection did not increase stiffness. The use of rings mounted with half-pins instead of a unilateral bar mounted with half-pins for diaphyseal fixation increased the stiffness of the frame only in torsional testing. CONCLUSIONS: Although the ideal stiffness of an external fixator is unknown, our results show that the addition of more than one level of fixation in the periarticular fragment increases the stiffness of hybrid external fixators in this periarticular tibia fracture model. Augmentation of the ring-to-bar connection did not significantly affect the stiffness of the frame.

Length of operative procedures: reamed femoral intramedullary nailing performed with and without a fracture table.

OBJECTIVES: To determine whether performing reamed intramedullary nailing of the femur without the use of a fracture table decreases the length of operation. DESIGN: Retrospective. SETTING: Level 1 trauma center, Nashville. Tennessee. PATIENTS/PARTICIPANTS: Consecutively treated patients with fractures of the femoral shaft were treated with intramedullary nails from June 1986 to March 1996. INTERVENTION: Reamed intramedullary nailing of the femoral shaft was performed with the use of a fracture table or with the leg draped free on a radiolucent table. MAIN OUTCOME MEASUREMENTS: Length of anesthesia time, prep and drape time (from the point the anesthetized patient is turned over to the surgeons until incision), and intramedullary nailing time (from incision until end of surgery) for reamed intramedullary nailing of the femoral shaft performed with and without the use of a fracture table were compared. RESULTS: Univariate analysis showed statistically significant decreases in the length of prep and drape time, operative time, and anesthetic time when fractures were treated without the use of a fracture table. Multivariate analysis showed that use of a fracture table prolongs prep and drape time (plus twenty minutes), operative time (plus seventeen minutes), and anesthesia time (plus seventy-three minutes) when the covariates of age, sex, fracture location, learning curve, position of the patient, nail brand, and number of distal bolts are controlled. CONCLUSIONS: Reamed intramedullary nailing of the femoral shaft performed without the use of a fracture table is significantly faster than when the procedure is performed with a fracture table.

Reamed intramedullary femoral nailing after induction of an "ARDS-like" state in sheep: effect on clinically applicable markers of pulmonary function.

OBJECTIVES/HYPOTHESIS: At present, the optimal treatment for appropriately resuscitated, multiply injured patients includes fixation of long bone fractures within twenty-four hours of injury. This management approach has been shown to decrease the incidence of pulmonary complications, multiple organ failure, and death. Some investigators have hypothesized that acute reamed intramedullary nailing of the femur (RIMNF) may result in pulmonary dysfunction as a result of the pulmonary fat embolization generated during this procedure. Patients with concomitant thoracic trauma may be at particular risk for this potentially severe complication. In an attempt to determine whether RIMNF can be safely carried out regardless of the severity of a pulmonary injury, we monitored the pulmonary effects of RIMNF in sheep in which an acute respiratory disorder (ARDS)-like state had been induced. Our hypothesis was that, if the pulmonary fat embolization that occurs as a result of RIMNF has a clinically significant effect, it would be detectable in an animal model in which a severe lung injury had been induced prior to the start of RIMNF. STUDY DESIGN: This was an acute experimental procedure performed on yearling sheep. METHODS: Reamed intramedullary nailing of the femur was performed in two groups of instrumented sheep. The first group had no pulmonary injuries. The second group had an ARDS-like state induced by intravenous infusion of perilla ketone prior to RIMNF. Perilla ketone increases pulmonary microvascular permeability without changing filling pressures and is used to induce a model of human ARDS. Hemodynamic and oximetric parameters were measured or calculated, as was pulmonary dynamic compliance during the experiment. RESULTS: Infusion of perilla ketone caused a significant pulmonary injury. RIMNF caused no additional significant effect on intrapulmonary shunt, mixed venous oxygen saturation, or dynamic compliance, which are clinically used to assess the severity of pulmonary dysfunction in injured patients. CONCLUSIONS: The fat embolization that occurs during RIMNF in an appropriately resuscitated sheep has no clinically significant effect on pulmonary function, even in the setting of a severe pulmonary dysfunction.

Assessment and management of pelvic fracture in the hemodynamically unstable patient.

Hypotensive patients with pelvic ring injuries present a diagnostic and therapeutic challenge. This article reviews pelvic anatomy, the classification of pelvic injuries, and how to rapidly identify patients' unstable pelvic injuries. Current recommendations for the evaluation and treatment of these patients are reviewed.

Effects on pulmonary physiology of reamed femoral intramedullary nailing in an open-chest sheep model.

We have recently developed an open-chest sheep model to monitor and study the effects of major orthopedic procedures on pulmonary physiology. In this pilot study, we focused on reamed intramedullary femoral nailing in animals without pulmonary injury. Details of the model are described herein. The control group consisted of sheep that underwent thoracotomy and invasive monitoring only, while the study group also underwent femoral osteotomy, reaming, and intramedullary nailing. Baseline, postthoracotomy, and post-reaming/nailing values were recorded for mean pulmonary arterial pressure, central venous pressure, left arterial pressure, dynamic compliance, arterial blood gas, mixed venous O2, cardiac index, and mean arterial pressure so that hemodynamic and oxygen transport data could be calculated. Postprocedure values were recorded at hourly intervals for 4 h. A physiologically stable, reproducible model was created. No statistically significant differences were found between the control and experimental groups, indicating no adverse effect of femoral reaming/nailing. In one animal, using echocardiography, pulmonary embolization was documented while reaming and inserting the intramedullary nail. Reamed femoral intramedullary nailing is not detrimental to sheep with otherwise normal lungs. This finding suggests that femoral reaming and nailing in trauma patients without associated pulmonary injuries and otherwise normal lungs may be carried out without risk of inducing significant respiratory complications.

Ipsilateral femoral neck and shaft fractures.

Ipsilateral femoral neck and shaft fractures occur in 2.5% to 6% of femur fractures. The injury results from high energy trauma. Victims are usually young, with multiple associated injuries. The diagnosis of the neck fracture is delayed in 19% to 31% of patients. The neck fracture line is almost vertical and nondisplaced, or minimally displaced in 26% to 59% of cases. The shaft fracture is often midshaft and open, and/or comminuted in 47% to 67% of cases. Ipsilateral knee injuries occur in 20% to 40% of patients. Two major complications, osteonecrosis of the femoral head and nonunion of the neck, result from the neck fracture. Therefore, treatment of the neck fracture takes precedence. The rate of osteonecrosis is unknown, but probably is in the range of 4% to 22%. Union rate of the neck is high and related to stable, anatomic reduction. The timing of operative fixation often is dictated by the patient's status as a multiple trauma victim, but a delay of days to weeks in the fixation of the neck fracture does not seem to increase the complication rate. The goal of any treatment plan should be anatomic reduction of the neck fracture, and stable fixation of both fractures, so that the patient can be mobilized.