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Comparison of fixation of the femoral component without cement and fixation with use of a bone-vacuum cementing technique for the prevention of fat embolism during total hip arthroplasty. A prospective, randomized clinical trial.

BACKGROUND: Acute hypotension, hypoxemia, cardiac arrest, and sudden death are well recognized complications during total hip arthroplasty, and they have been attributed to embolization of fat and bone marrow. An increase in intramedullary pressure in the femur is the most important pathogenic factor for the development of embolic events. Intravasation of fat, bone marrow, and bone debris during the implantation of a femoral component, and the embolization of these elements through the venous system located along the linea aspera and through the metaphyseal vessels, have been demonstrated experimentally and clinically. The purpose of the present study was to compare the effects of fixation of the femoral component without cement with those of fixation with a bone-vacuum cementing technique on the severity of embolic phenomena and cardiopulmonary impairment during total hip arthroplasty. Fixation with a conventional cementing technique was also evaluated as a control. METHODS: Sixty patients (sixty hips) were entered into a prospective, randomized clinical trial. The patients were assigned to one of three groups. Group 1 consisted of twenty patients who had the femoral component inserted without cement, Group 2 comprised twenty patients who had the component inserted with a conventional cementing technique, and Group 3 included twenty patients who had fixation with the so-called bone-vacuum cementing technique. In the hips in Group 3, a suction of -800 millibars (-80,000 pascals) was applied to a proximal drainage cannula placed along the linea aspera and a distal drainage cannula placed in the diaphysis in order to produce a vacuum in the medullary cavity of the femur during the application of cement and the insertion of the stem. Transesophageal echocardiography and hemodynamic and blood-gas analysis were performed during the operation. RESULTS: Severe embolic events (defined as a cascade of fine echogenic particles of less than five millimeters in diameter) were observed in seventeen (85 percent) of the twenty patients during insertion of the stem with use of a conventional cementing technique but in none of the patients who had the stem inserted without cement (p < 0.05). Insertion of the femoral component with the bone-vacuum cementing technique prevented embolic phenomena in all but one patient (5 percent). Arterial oxygen saturation decreased significantly (p < 0.05) from a mean of 99.5 to 92.9 percent after insertion of the stem with a conventional cementing technique, but only slight changes were observed in the patients who had fixation of the component without cement and in those who were managed with the bone-vacuum cementing technique. Intraoperative pulmonary shunt values increased a mean of 24 percent (p < 0.05) when the femoral component was inserted with a conventional cementing technique, but with the numbers available we did not detect a significant change in those values when the component was fixed without cement or when it was inserted with use of the bone-vacuum cementing technique. CONCLUSIONS: The present study showed that severe embolic events and intraoperative pulmonary impairment are common when a femoral component is fixed with use of a conventional cementing technique. The results clearly demonstrated a low risk of embolism during total hip arthroplasty when the femoral component was fixed without cement and when it was fixed with the bone-vacuum cementing technique. The ability of a patient to withstand an embolic event should be considered before fixation of the femoral component with use of a conventional cementing technique is planned.

Aged↗

[Electron microscopic detection of ATPase activity in insect muscle after fixation with different fixatives].

The distribution of ATPase activity in the flight muscle of Locusta migratoria L. was studied at the fine structural level after a brief fixation in formaldehyde or in glutaraldehyde. In both the cases, the final product of reaction -- fine grained electron dense precipitation--was clearly revealed in intact contractile muscle structures. The glutaraldehyde fixation provides a good preservation of all the ultrastructural components of muscle cell, and reveals deposites of the final product in sarcomeres at the resting length. However, after the glutaraldehyde fixation it is very difficult to recognize regions of fibrillar reaction on electronmicroscopic preparation. The formaldehyde fixation does not provide a good preservation of membranous structures. However after the formaldehyde fixation reacting regions are more extensive than after glutaraldehyde fixation, and, moreover, it is possible to demonstrate a correlation between the activity and the contraction of sarcomere.

Adenosine Triphosphatases↗

Comparing staple fixation to buttress plate fixation in high tibial osteotomy.

A retrospective study was made between July 1988 and March 1992, of 171 patients (223 knees) who had high tibial osteotomy at the Singapore General Hospital. Seventy-four cases (97 knees) had buttress plate fixation and 97 cases (126 knees) had staple fixation. The mean postoperative Hospital for Special Surgery Knee Score was 87.0 for the buttress plate group and 87.4 for the staple group. The difference was statistically not significant (P > 0.05). The hospitalisation stay was shorter in the staple fixation group as compared to the buttress plate group (P < 0.05). However, the mean rehabilitation time was shorter in the buttress plate group as compared to the staple fixation group (P < 0.05). The incidence of wound infection was higher among those fixed with buttress plate (9 cases) as compared to those fixed with staple (1 case). The difference was statistically significant (P < 0.05). Buttress plate fixation did not seem to eliminate the risk of non-union of the osteotomy (4 out of 126 osteotomies compared to 3 out of 97 in the staple group), neither did it prevent recurrence of varus deformity (2 out of 126 osteotomies). Overall it would appear that buttress plating did not have any significant advantage over staple fixation for high tibial osteotomy.

Female↗

Displaced intra-articular fractures of distal radius: a comparative evaluation of results following closed reduction, external fixation and open reduction with internal fixation.

Fractures of the distal end of the radius are common injuries and are the commonest bony injury around the wrist. Management of these fractures has remained controversial as far as modality of treatment is concerned. In this study 90 adult cases of acute displaced intra-articular fractures of the lower end of the radius were classified according to Frykman's and AO classifications after obtaining radiographs in antero-posterior and lateral planes. These were randomly treated by one of three methods: (1) closed reduction and plaster immobilisation, (2) external fixation and (3) open reduction and internal fixation, and were followed for an average of 4 yr. In the final functional assessment (Sarmiento) the results were (1) plaster 43% good and excellent, 50% fair and 7% poor, (2) external fixator 80% good and excellent, 20% fair and poor results, (3) open reduction and internal fixation 63% good and excellent, 26% fair, 11% poor. We recommend that displaced severely comminuted intra-articular fractures should be treated with an external fixator.

Adult↗

External skeletal fixation. Linear fixators.

Linear external skeletal fixators offer some unique advantages over other fixation systems; they are biomechanically versatile, minimize surgical trauma to the fracture environment, and allow for simple staged disassembly to help promote bone healing. Historically, the use of linear external skeletal fixators has been reported to result in numerous complications, primarily related to the pin-bone interface. External skeletal fixators have experienced a resurgence in the past two decades. Increased knowledge of proper pin insertion techniques and advancements in pin design have greatly enhanced the longevity of the pin-bone interface, resulting in fewer complications. This article reviews some of the potential advantages of linear external skeletal fixators and principles of application to help strengthen the pin-bone interface and minimize complications.

Animals↗

Use of an orthopaedic fixator for external fixation of the mandible.

A patient presented with a chronically infected, non-united fracture of the mandible, with considerable bone loss. He was treated with a metacarpal fixator, the miniPennig external fixator. The fixator is stable and smaller than conventional mandibular fixators. It can be applied and removed under local anaesthesia, if necessary, requires little maintenance and produces minimal scarring. The successful outcome in this patient is encouraging and we commend the use of the fixator in similar difficult cases.

Adult↗

Limited internal fixation of the tibia with external fixation: an in vivo canine study.

This study reports the results of the healing of canine tibial osteotomies with external fixation alone or in combination with a single lag screw. Twelve dogs had a midshaft tibial osteotomy performed at a 45 degree obliquity. Half of the dogs had a six-pin, unilateral, medial, external half-frame applied after the osteotomy. The remaining six had an identical frame plus a lag screw placed perpendicular to the osteotomy site. When compared with their contralateral controls, the fixator-alone group had a 16.3% (p < 0.05) decrease in bone density, whereas no significant density change was seen in the group with the additional lag screw. Torsional stiffness was 29% higher in the osteotomies treated, and tested, with the lag screw, but this did not achieve statistical significance. Computed tomography scanning revealed that the surface area was increased by an average of 30-40% in both groups, relative to contralateral controls, but there was no difference between the two treatment groups. Three tibias in the group with external fixation alone, and two tibias in the screw group showed primary bone healing without evidence of callus formation. The combination of a semirigid external fixation construct with a lag screw resulted in increased torsional stiffness but healing equal to that seen with external fixation alone.

Animals↗

Evaluation of Streck tissue fixative, a nonformalin fixative for preservation of stool samples and subsequent parasitologic examination.

We undertook a study to evaluate Streck tissue fixative (STF) as a substitute for formalin and polyvinyl alcohol (PVA) in fecal preservation. A comparison of formalin, PVA, (mercuric chloride based), and STF was done by aliquoting fecal samples into each fixative. Stool specimens were collected in Haiti, and parasites included Cyclospora cayetanensis, Giardia intestinalis, Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Ascaris lumbricoides, Trichuris trichiura, Strongyloides stercoralis, and Necator americanus. Preserved stools were examined at various predetermined times (1 week, 1 month, and 3 months) to establish the quality of the initial preservation as well as the suitability of the fixative for long-term storage. At each time point, stool samples in fixatives were examined microscopically as follows: (i) in wet mounts (with bright-field and epifluorescence microscopy), (ii) in modified acid-fast-, trichrome-, and safranin-stained smears, and (iii) with two commercial test kits. At the time points examined, morphologic features remained comparable for samples fixed with 10% formalin and STF. For comparisons of STF- and 10% formalin-fixed samples, specific findings showed that Cyclospora oocysts retained full fluorescence, modified acid-fast- and safranin-stained smears of Cryptosporidium and Cyclospora oocysts were equal in staining quality, and results were comparable in the immunofluorescence assay and enzyme immunoassay commercial kits. Stool fixed in STF and stained with trichrome showed less-than-acceptable staining quality compared with stool fixed in PVA. STF provides an excellent substitute for formalin as a fixative in routine examination of stool samples for parasites. However, modifications to the trichrome staining procedures will be necessary to improve the staining quality for protozoal cysts fixed in STF to a level comparable to that with PVA.

Animals↗

[Unilateral external fixator combined with simple internal fixation for severe open tibia-fibular fracture].

OBJECTIVE: To improve the treatment for severe open tibia-fibular fracture. METHODS: From 1994 to 2000, 146 patients with severe open tibia-fibular fracture were treated. According to Gustilo classification, all patients were of type III. Among them, 96 patients belonged to III A, 36 III B, and 18 III C. One hundred and eight patients were male and 38 female, aged from 11 to 68 years, with an average of 31. All patients were treated with unilateral external fixator combined with simple internal fixation (general screw or Kirschner wire). Thirty patients were treated with secondary flap operation. Among them, 19 patients received pedicle gastrocnemius muscle flaps, 9 free vastus lateralis muscle flaps, and 2 free latissimus dorsi muscle flaps. RESULTS: Three patients of type IIIB were subjected to amputation because of advanced age and associated cerebral or thoraco-abdominal injury. Five patients of type III C had amputation because of insufficient postoperative blood supply and necrosis. The rupture of other 138 patients was well reduced, and firmly fixed. They were followed up for 6 months-6 years, with an average of 2.5 years. The average time of fracture-union was 27 weeks, and the average time for removal of fixtors was 28 weeks. The motion of knee joint ranged from 0 to 120 degree in 110 patients; from 0 to 100 degrees in 25, and from 0 to 90 degrees. The motion of ankle joint was approximately normal. CONCLUSIONS: For patients with severe open tibia-fibular fracture, comprehensive analysis should be made for preservation of the wounded limb or amputation as for elderly patients with vessel-nerve injury or with cerebral- thoracoabdominal injury, emergency amputation should be done. Unilateral external fixator combined with simple internal fixation (general screw or Kirschner wire) for severe open tibia-fibular fracture is advantageous for a simple and reliable fixation. It is less traumatic.

Adolescent↗

Biomechanical analysis of fracture fixation with external fixator in vivo.

OBJECTIVE: To investigate the different ways of measuring the main axial strain during treatment with an external fixator and to find the suitable compression loaded by the external fixator at an early stage. METHODS: Eighteen healthy big-ear rabbits were randomly divided into two groups according to different measuring methods: Group A and Group B. In Group A, a strain gauge was affixed to the external tibial cortex with 502 glue, and in Group B, a bone cement-coated strain gauge was installed on the internal tibial cortex. Groups A and B were divided into two subgroups A1, A2 and B1, B2, respectively, according to the pressure of half of and the same as the body weight. A Z-shaped left mid-shaft tibial osteotomy was performed and fixed by an external fixator. RESULTS: The scaler curves of Group A changed dramatically during the early stage. The trendlines of the internal and external cortex went consistently after reaching the stable stage while the latter strain value was higher than the former. The time for Group B reaching the stable stage was short, but its absolute strain value was less than that of Group A. Before they were pressed to the stable stage, the declined speed of Subgroup A1 was more slowly than that of Subgroup A2 while the results of Subgroups B1 and B2 were same. Group A had an ascending trend after it declined while Group B didn't have. After they reached the stable stage, both Subgroups A1 and A2 had a declining trend while Subgroup A2 was more quickly than Subgroup A1, Subgroup B1 was kept at a definite level while Subgroup B2 fluctuated. CONCLUSIONS: The axial strain under external fixator can be measured by bone cement coated-strain gauge in vivo. The data may suggest that half of the body weight load was suitable for external fixator.

Animals↗

[Comparison between solis fixation fusion and titanium plate fixation by cervical anterior approach].

OBJECTIVE: To investigate the effect difference between the Solis fixation fusion and the titanium plate fixation by the cervical anterior approach after decompression and bone graft implantation. METHODS: Of the 104 patients with cervical disease from September 2001 to March 2004, 36 were treated with the Solis implantation after decompression by the cervical anterior approach, and 68 were treated with the titanium plate fixation after decompression and bone graft implantation. The recovery of the neurological function in all the patients were assessed with the JOA Scoring at 6 weeks, 3, 6, 12, 24 and 36 months. The fragment fusion and its stability as well as the changes in the intervertebral height were assessed with X-ray examination. RESULTS: According to the JOA Scoring, the excellent and good outcomes accounted for 94.4% in the Solis group and 94.1% in the titanium plate group. In all the patients, the fragment fusion was achieved in 3 months. The change in the Cobb angle of the fused fragment was less than 5 degrees at the flexion-extension posture, 3.6 +/- 0.8 degrees in the Solis group, 2.4 +/- 0.7 degrees in the titanium plate group. There was significant differences between the two groups (P < 0.05). The intervertebral height of the operation fragment in the Solis group increased 1.6 +/- 0.7 mm, which was higher than that in the titanium plate group (P < 0.05). CONCLUSION: Clinical effects of the two internal fixation operations are good; however, the Solis fixation has more advantages because of its simpler performance, less trauma, and fewer complications.

Adult↗

Treatment of open ankle fractures. Immediate internal fixation versus closed immobilization and delayed fixation.

Thirty-one open ankle fractures were treated over a period of 11 years and retrospectively reviewed with an average follow-up period of 61 months. Fifteen were managed by closed immobilization and delayed internal fixation. Sixteen were treated with immediate open reduction and internal fixation. One case in each group became infected. Functional scores at follow-up examination were the same for both groups. The fractures treated with immediate open reduction and internal fixation showed less impairment of range of motion but had a greater incidence of chronic ankle swelling. The hospitalization time was significantly shorter for the patients treated by open reduction and internal fixation. Immediate open reduction and internal fixation of open ankle fractures speed recovery with no greater incidence of infection than encountered with conservative treatment.

Adolescent↗

Fixation of cancellous bone and physeal fractures in dogs and cats. A comparison of the use of self-reinforced biodegradable devices to the use of metallic devices and external fixations.

The use of self-reinforced biodegradable devices made of polyglycolide in the cancellous bone and physeal fractures of dogs and cats was compared to the use of metallic devices and external fixations on similar fractures. The series consisted of 64 dogs and 22 cats divided into 6 comparable groups. The patients in the 2 groups fixed with biodegradable devices started to use their operated limbs earlier than in the other groups. The same 2 groups also healed clinically (showed no lameness) earlier than the other groups. Radiographically there was no statistical difference between the 6 groups. On the basis of this study it may be concluded that the fixation with self-reinforced biodegradable devices is as suitable for the fixation of cancellous bone and physeal fractures of dogs and cats as the fixation with metallic devices or external fixation. This biodegradable technique has additional benefits allowing the patients to feel less pain in their operated limbs and making secondary operations to remove the devices unnecessary.

Animals↗

Behavior of an external fixation frame incorporating an angular separation of the fixator pins. A finite element approach.

A finite element model has been developed to simulate the deformation that occurs at the fracture site of an externally fixed bone as a result of applied bending, compression, and torsional loads. The pin configuration in this model is constructed to allow an angular separation of the fixator pins. The mechanical effect of this angular separation and of the distribution of the pins along the fixator bar is examined. The model shows that an angular separation of the pins provides a more symmetric deformation of the fracture site when a bending load is applied in different directions to the bone and thereby protects a fracture from excessive movement in any direction. The torsional stability of an external fixation frame is considerably increased by incorporating an angular separation of the pins. The model also shows that the most stable configuration for the fixator uses a wide separation of the pins along the fixator bar.

Computer Simulation↗

[Internal fixation of thoracolumbar, lumbar and lumbosacral spine with internal fixators].

The report is a review of the literature on fully implantable transpedicular fixation device known under the general name internal fixator, and designed for short (one to three segments) internal fixation of the spine in various pathologies. The implants are found in a routine clinical use throughout many European countries and have become more familiar to spine surgeons in the U.S. The authors present a general description of the fixators, indications and contraindications to their implantation, the implantation technique and possibilities of intraoperative reposition of the spine. The advantages of usage of the fixators and the history of their development are presented.

Equipment Design↗

Kinetic study of collagen fixation with polyepoxy fixatives.

A new biomaterial has been developed by fixing native collagen with a polyepoxy compound (PC) fixative. In this study, bovine internal thoracic arteries were fixed with PC under various conditions to help understand the kinetics of the collagen-PC reactions and optimize the fixation process. At predetermined time intervals, small samples were cut from the arteries to determine the quantities of the remaining unreacted amino acids in the collagen. Temperature, concentration, and solution pH were among the key parameters studied. The overall fixation rate was found to be reaction-rate controlled, as the rate of fixation was relatively slow compared with the rate of diffusion of PC. As might be expected, the reaction rate was favored by a higher temperature, concentration, and solution pH. A kinetic model, with a 2.5th reaction order with respect to the reactive functional groups of collagen and a first order with respect to PC, was developed that gave a good fit to the experimental data. Based on this model, the degree of fixation, X, as a function of time, t, is given by (1 - X)-1.5 = 1 + Kt, where K is a constant related to the initial concentrations and the reaction rate constant.

Amino Acids↗

External fixation of tibial shaft fractures. A review of 42 fractures by the Hoffman-Vidal-Adrey external fixation system.

Over a 6-year period (1977-1983), 59 patients with 61 tibial shaft fractures were treated by external fixation. Of these patients, 42 with 42 fractures were followed up until solid union. Thirty-seven fractures were caused by high-energy impact, mainly road accidents. Seventeen fractures were closed and 25 were open. In 33 patients an external quadrilateral frame system was applied primarily, and in the remaining nine within 1-2 weeks. No predrilling was done, and in 16 patients nonthreaded connection rods were used throughout the period in the fixator. The process of union was monitored by repeated noninvasive measurements of stability. Average time form injury to dismantling of the external fixation was 5.2 months (range 2-12.5 months) and time-to-union for the whole series was 10.0 +/- 5.5 months (range 4-31 months). Sixteen fractures failed to unite. Compared with other published series treated by external fixation, the incidence of non-union in the present series is high. On the basis of the present findings it is concluded that a compression device should be mounted either primarily or as soon as possible during the process of union, and that compression should be applied at regular intervals. If an external fixator is used, the surgeon must bear in mind the possible complications. It is probably safer to reduce rather than to prolong time-to-removal of the external system.

Adolescent↗

In situ fixation of cultured mouse peritoneal exudate cells: comparison of fixation methods.

Mouse peritoneal exudate cells grown in vitro on plastic petri dishes were fixed in situ with both glutaraldehyde and osmium tetroxide by a variety of contemporary methods. The goal of the investigation was to determine which method resulted in the best ultrastructural preservation. The parameters being tested included: (a) the method of fixation, i.e. either sequential or simultaneous; (b) the buffer vehicle for fixation, i.e. cocodylate, Mellonig's phosphate, Sorenson's phosphate, or s-collidine; and (c) the temperature of fixation. Results presented indicate that simultaneous fixation is far superior to sequential methods. Samples fixed sequentially at 4 degrees C consistently had better morphological preservation than samples fixed under similar conditions at 23 degrees C. With the exception of s-collidine, which was totally unacceptable for in vitro in situ fixation on plastic, comparable results were noted with different buffer vehicles.

Animals↗