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Results for “External Fixators”

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At least 127 records · Page 7Linked to original sources

PubMed2005

Unilateral external fixator in the treatment of lower third humeral shaft fractures.

OBJECTIVE: To retrospectively analyze the effect of unilateral external fixators in the treatment of lower third humeral shaft fractures. METHODS: From October 1997 to October 2003, 33 patients aged 15 -70 years (average 31 years) with lower third humeral shaft fractures were treated with unilateral external fixators. There were 9 spiral fractures (type A1), 1 oblique fracture (type A2), 3 transverses fractures (type A3) and 20 comminuted fractures (11 type B1, 9 type B2) according to AO classification. Fifteen cases were treated with open reduction and limited internal fixation and fixation with external fixators, 10 cases treated with open reduction and fixation with external fixators, and 8 cases treated with closed reduction and fixation with external fixators. Nerve exploration was undertaken in 9 cases with preoperative radial nerve injury. External fixators were removed after bone healing. The average follow-up was 18 months with a range from 8 to 24 months. RESULTS: The time of bone healing ranged 11-22 weeks (average 14 weeks). The latest follow-up showed the functions of 9 cases of preoperative radial nerve injury and of 2 cases postoperative radial nerve injury and the function of elbow were recovered to normal. There were only 7 cases of superficial infection at pin hole, which was subsided by using oral antibiotics and pin-hole care with mild disinfectants. CONCLUSIONS: Fixation with unilateral external fixators combined with open reduction and limited internal fixation has a good effect in the treatment of lower third humeral shaft fractures.

Adolescent↗

PubMedDate not supplied

Suitability of external fixators for use in the tropics.

External fixation systems proved to decrease the osteomyelitis rate in patients in the tropics compared with internal stabilization. This study was designed to show how external fixators being used for treatment of patients in industrial countries compare with cheap alternatives regarding their suitability for the application in tropical countries. Eleven external fixation systems were compared for stability, cost, weight, variability, handling, and capability of being produced locally. Stiffness, slipping moment, and irreversible deformation were determined in material testing machines. The technically best fixators are expensive and cannot be manufactured locally. The inexpensive constructs lack variability and stability. When cost is not a problem, the Synthes model is recommended. With some restrictions in mechanical stability and variability, the Pfeifer Fixator II and a wooden model offer inexpensive and locally producible alternatives. These results may help to select an external fixation device to meet local needs and possibilities in tropical countries.

Biomechanical Phenomena↗

PubMed1992

External fixator pin design.

The integrity of the bone-pin interface is the critical link in the stability of external fixation systems. External fixation pins placed in cancellous metaphyseal bone frequently loosen over time, resulting in fixation failure and an increased risk of infection. To design an external fixation pin with optimal bone-metal interface strength in cancellous bone, a systematic study of various thread design features was performed. Combinations of pitch, tooth profile, and minor diameter in 5 mm self-tapping half pins were evaluated in coaxial pullout testing using a fresh bovine cancellous bone. A significant increase in pullout strength was found with a decrease in minor diameter. No statistical differences were found in pullout strength attributable to thread profile and pitch. There were no significant interactions between minor diameter and tooth profile or minor diameter and pitch. The data obtained suggest significantly greater holding power in cancellous bone can be achieved by using an external fixation pin with a smaller minor diameter or a larger interference. Additional pullout testing of five commercially available external fixator pins was performed. Of these, the two pins with the largest interference demonstrated greater pullout strength. Therefore, within a range of acceptable major diameters and adequate minor diameters for the torsional strength requirements, an optimal interference for cancellous pin application may exist and it may well be larger than that present in currently available external fixation pins.

Animals↗

PubMed1989

The role of external fixation in pelvic disruptions.

External fixation has a definite role in the management of pelvic fractures. Biomechanically, it is not useful for maintaining reduction of the unstable, vertically migrating pelvis and must be used with some other form of treatment, such as traction, spica cast, or internal fixation. In vertically stable fractures, that is, rotationally unstable fractures, the anteroposterior and lateral compression injuries, the external fixator should probably be the first course of treatment.

Adult↗

PubMed2006

A biomechanic comparison of an internal radiocarpal-spanning 2.4-mm locking plate and external fixation in a model of distal radius fractures.

PURPOSE: To compare the biomechanic stability of distal radius fracture fixation with a new internal radiocarpal-spanning 2.4-mm locking plate, which acts as an internal distal radius fixator, versus a standard distal radius external fixator. The number of locking screws necessary for adequate fracture fixation was also assessed. METHODS: Ten cadaveric specimens were mounted in a loading fixture with cables attached to the 2 flexor and 3 extensor wrist tendons. A 1-cm osteotomy was created to simulate an unstable distal radius fracture. The radiocarpal-spanning locking plate was fixed to the radius and index metacarpal with 4 screws proximally and 4 distally. The specimen was incrementally loaded through the tendons. Motion at the fracture site was determined. Screws were sequentially removed from the construct, the specimen was again incrementally loaded, and fracture motion was measured. The fixation was then changed to an external fixator, and the loading tests were repeated. RESULTS: Fracture fixation with the radiocarpal-spanning 2.4-mm locking plate was significantly more stable with 4 screws proximally and 4 screws distally (4 x 4) and with the 3 x 3 configuration than with the external fixator in both flexion and extension. The 4 x 4 screw configuration was not significantly different from the 3 x 3 screw configuration. The 4 x 4 screw configuration was significantly more stable than the 2 x 2 and 1 x 1 screw configurations in both flexion and extension. All internal fixator configurations and the external fixator showed more fracture displacement at increasingly higher loads. CONCLUSIONS: Fracture fixation with the new internal radiocarpal-spanning 2.4-mm locking plate is more stable than with a standard distal radius external fixator. Only three 2.4-mm locking screws proximally and three 2.4-mm locking screws distally are required for adequate fixation of the locking spanning plate.

Aged↗

PubMed2001

Structural stiffness and reducibility of external fixators placed in malalignment and malrotation.

OBJECTIVE: To determine the structural stiffness and reducibility of various external fixators placed in malalignment and malrotation. DESIGN: Uniform testing of all external fixator configurations. SETTING: Orthopaedic biomechanical laboratory. METHODS: Thirteen external fixators from different manufacturers, in a total of fifteen configurations, were studied. All external fixators were applied to a malreduction jig initially, and a subsequent anatomic reduction was then attempted. If an anatomic reduction was possible, the structural stiffness of those fixators was determined. If anatomic reduction was not possible, the external fixator was removed and reapplied to an anatomically reduced model, and then structural stiffness was determined. RESULTS: Six of the thirteen external fixator configurations allowed an anatomic reduction after placement on a malreduction model. The other nine external fixator configurations would not allow for an anatomic reduction. All the external fixator configurations were biomechanically tested in anteroposterior bending, lateral bending, axial load, and torsion. Each fixator had its own structural stiffness and is reported. CONCLUSIONS: Some external fixators will not allow for an anatomic reduction once placed in malalignment and malrotation without repositioning of the fixator pins. External fixator configurations (i.e., single-pin, dual-pin, and multipin barclamps) affect structural stiffness. Structural stiffness widely varied among the external fixators. Proper external fixator selection will enable early fracture immobilization in malalignment and malrotation in suboptimal conditions (e.g., wartime conditions or a civilian disaster), with subsequent external fixator adjustment for an anatomic reduction.

Biomechanical Phenomena↗

PubMed2003

Treatment of tibial defect and bone nonunion with limb shortening with external fixator and reconstituted bone xenograft.

OBJECTIVE: To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening. METHODS: Twenty patients (13 males and 7 females) with tibial bone defect, tibial bone nonunion or congenital pseudarthrosis of the tibia with limb shortening were treated with external fixation. Two kinds of external fixators were used: a half ring sulcated external fixator used in 13 patients and a combined external fixator in 7 patients. Foot-drop was corrected at the same time with external fixation in 4 patients. The shortened length of the tibia was in the range of 2-9 cm, with an average of 4.8 cm. For bone grafting, RBX was used in 12 patients, autogenous ilium was used in 3 patients and autogenous fibula was implanted as a bone plug into the medullary canal in 1 case, and no bone graft was used in 4 patients. RESULTS: All the 20 patients were followed-up for 8 months to 7 years, averaging 51 months. Satisfactory function of the affected extremities was obtained. All the shortened extremities were lengthened to the expected length. For all the lengthening area and the fracture sites, bone union was obtained at the last. The average healing time of 12 patients treated with RBX was 4.8 months. CONCLUSIONS: Both the half ring sulcated external fixator and the combined external fixator have the advantages of small trauma, simple operation, elastic fixation without stress shielding and non-limitation from local soft tissue conditions, and there is satisfactory functional recovery of affected extremities in the treatment of tibial bone defects, tibial bone nonunion and congenital pseudarthrosis of the tibia combined with limb shortening. RBX has good biocompatibility and does not cause immunological rejections. It can also be safely used in treatment of bone nonunion and has reliable effect to promote bone healing.

Adolescent↗

PubMed1989

Structural stiffness of the Hoffmann simple anterior tibial external fixation frame.

Tibial external fixation frames were constructed on aluminum tube simulating tibia bone. A 20-mm gap was left at the fracture site in order to measure the structural stiffness of the frame rather than the aluminum tube. The performance of the frames were experimentally evaluated and quantified using tests which simulated the loading conditions encountered in normal walking. These included axial compression, anteroposterior (AP) bending, lateral bending and torsional loading of the frame. The parameters studied were (a) number of fixation pins, (b) number of connecting rods and (c) location of clamps on the pins. Four constants were evaluated from these tests using various structural configurations of the frames; these resulted in four stiffness coefficients in compression, AP bending, lateral bending and torsion. Stiffnesses of various frames with different geometric configurations were compared by comparing their appropriate stiffness coefficients. Such comparison can set forth a quantitative guideline in selecting a suitable frame configuration for the type of injury and condition of fracture pattern. This type of quantitative analysis can also be useful in modifying the frame during the postoperative bone healing process.

Equipment Design↗

PubMed1981

Which external fixation device?

Seven external fixation frames which are used for the treatment of fractures have been evaluated. The features of these devices are presented and some of the advantages and disadvantages of each are described.

Bone Nails↗

PubMedDate not supplied

Limb lengthening with the Ilizarov external fixator.

The Ilizarov External Fixator is used to lengthen or widen bones, to correct angular or rotational defects, or to immobilize fractures. This article discusses techniques of application and care of the device; physiology and mechanics of limb lengthening and bone regeneration; and nursing strategies to achieve patient compliance and prevent complications.

Bone Lengthening↗

PubMed1998

Sliding performance of unilateral external fixators for tibia.

Some unilateral external fixators have a sliding mechanism to achieve dynamic axial fixation. However, it has been reported that binding of this mechanism occurs during routine ambulation. The Hifixator, a unilateral external fixator, has been developed which has a new type of sliding mechanism. The mechanism of the Hifixator was tested by connecting it to a fractured bone model with pins, and applying dynamic axial loading. The conditions of connection between the pins and bone model were varied to simulate loosening of the pins. Two other external fixators commonly used for tibias, Orthofix and Monotube (blue), were tested for comparison. The amount of sliding motion of the Hifixator was maintained at more than 72% of the motion at the fracture site even when pins were loose and a torque of 4 N m was applied. The sliding mechanism of the Hifixator was shown to be more durable than those of the other fixators tested for conditions found in application to tibias.

Biomechanical Phenomena↗

PubMed1990

External fixation in multiply injured children.

External fixation treatment for selected fractures can be as readily applied to children as to adults, although only a small percentage of pediatric fractures require this method. The best situations for the use of external fixation in children are in cases of multiple organ system injuries and in fractures associated with skin loss or large wounds. In these situations, while the child's other problems are being treated, external fixation provides excellent temporary stabilization to facilitate fracture management.

Adolescent↗

PubMed2002

Treatment of distal radius fractures with external fixation: technical considerations for rehabilitation.

Wrist external fixation with or without K-wire stabilization has been shown to be a reliable treatment method for unstable fractures of the distal radius. The technique of external fixation of the wrist has been historically based on the premise that fracture reduction can be achieved and maintained using the principles of ligamentotaxis. It is now well recognized that sustained longitudinal traction applied with a wrist external fixator can lead to complications. This review outlines the authors' preferred technique of using the external fixator as a neutralization device rather than as a traction device. The absence of sustained radiocarpal traction during distal radius fracture healing may facilitate postoperative rehabilitation.

Journal Article↗

PubMedDate not supplied

[External fixation war injuries of the proximal humerus].

Nine patients with open fractures of the proximal humerus were treated using an external fixation device. All of them had grade III open fractures resulting from high-velocity missile and explosive injuries with massive foreign body contamination. Radial nerve injury was present in five and two multiply injured patients with thoracic wall and abdominal viscera were present. There were no major arterial injuries. Chronic osteitis with fistula and sequestra developed in one. There were no nonunions and no refractures. Minor painless limitation of shoulder and elbow motion presented in all patient. Upper-third humeral open fractures due to firearms are a unique type of open fractures. They are usually highly comminuted therefore, stable fixation is difficult or impossible to achieve. On the other hand, the risk of infection is high following plate fixation. External fixation allows adequate management of the soft tissue wounds, provides stable bone fixation and allows early mobilization of the shoulder and elbow.

External Fixators↗

PubMed2004

The bridge and barrel hoop plates as alternatives to external fixation techniques in the foot and ankle.

External fixation is a useful tool for treating severe traumatic injuries to the foot and ankle. External fixation, however, does have associated complications, such as inadequate fixation and pin tract infections. Temporary bridge plating of the medial, lateral, or both columns is a useful alternative to external fixation for treating multilevel foot injuries. This article describes the technique of temporary bridge plating which may be used as an alternative to external fixation.

Adolescent↗

PubMed1976

External fixation in maxillofacial surgery.

The role of external fixation in the treatment of facial fractures is well defined. If standard open reduction and internal fixation techniques do not yield a satisfactory result, external fixation techniques may be required. Open reduction has the advantage of effecting precise approximation of fragments. However, this type of fixation may be inadequate, either because no stable point is available or because the angle of traction involved in fixation may result in displacement of the reduced fracture and subsequent malunion. When the facial skeleton is fractured, it tends to collapse inward, and if injury is severe, an external traction point anterior, lateral, or superior to the facial skeleton may be required to obtain a satisfactory result. There are occasions when intermaxillary fixation may be inadvisable, and in these instances external fixation techniques may be an appropriate means of immobilization. Finally external fixation techniques may be required in instances in which massive tissue loss precludes the use of standard open reduction and internal fixation techniques. It must be reemphasized that the methods of external fixation described here are not meant to supplant the standard techniques of open reduction and interosseous wiring, but when judicially employed complement them in achieving the desired result of precise reduction and firm fixation of the fractured facial skeleton.

Fracture Fixation↗

PubMedDate not supplied

Transfer techniques of the lower extremity with an external fixator.

This article describes the uses of external fixation for lower extremity problems and addresses some issues related to the correct way to lift an extremity with an external fixator. The differences in opinions between nurses and among physicians is discussed, followed by suggestions for solving this confusion within the settings in which people work. The article then pictorially demonstrates how to lift an extremity with an external fixator. It proceeds through a series of photographs depicting how to transfer a patient into a chair by supporting the extremity, and again by supporting the external fixator itself.

Beds↗

PubMed2003

External fixation in trauma of the foot and ankle.

External fixation as a modality is a versatile and minimally invasive stabilization option that should not be forgotten even as new and specially designed implants for nearly each bone become more fashionable. As a temporary traction device, the external fixator can help condition the soft tissues and, if closed reduction was sufficient, it can stay in place for definitive treatment. The external fixator can be used as an intraoperative distraction device and as a helpful tool for reduction, which can stay in place as a temporary immobilization. External fixation instead of plaster cast allows for better care of skin and soft tissues. External fixation also has its advantages as a minimally invasive external compression device in specific indications for arthrodesis, especially in infected cases.

Ankle Injuries↗