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PubMedDate not supplied

Comparison of dynamic versus static external fixation for pediatric femur fractures.

External fixation of pediatric femoral shaft fractures has the advantages of minimal dissection and early weight bearing. However, it is associated with slow healing and potential for refracture. Some surgeons have proposed that axial dynamization may improve the speed and strength of callus formation. to test this hypothesis, we performed a randomized controlled trial using 53 femur fractures in 52 patients between 1995 and 1999. Patients were randomized to receive dynamic or static fixation. Average time until early callus formation was 23.2 days for dynamic fixation and 24.9 days for static fixation (P = 0.627). Average time until complete radiographic healing was 70.1 days for dynamic fixation and 63.1 days for static fixation (P = 0.370). Similarly, the differences in time to fixator removal and to full weight bearing did not reach statistical significance. The conclusion was that axial dynamization of external fixation for pediatric femur fractures has no significant effect on time to healing or frequency of complications.

Child↗
PubMed2002

Mechanical strength and wear of used EBI external fixators.

Thirty-one EBI external fixators (Dynafix; EBI, Parsippany, NJ) subjected to one or two clinical uses underwent static mechanical testing identical to that performed on new devices prior to market approval. No fixator exhibited catastrophic mechanical failure. For all fixators tested, the mean load to failure was not significantly different from that of identical testing of new devices. Although loss of material from serrated joints was observed in some joints, mechanical strength was not affected. Additional testing of fixators of a variety of designs is necessary to expand on the results of this investigation. The results of this study represent a first step in validating the safety of external fixator component reuse.

Equipment Failure↗
PubMed1995

Intramedullary nailing after external fixation of the tibia.

Intramedullary nailing after external fixation of fractures of the tibia has high complication rates including nonunion and infection. The authors review the literature regarding this technique and refine the indications for secondary IM nailing. The report distinguishes between sequential secondary nailing and reconstructive secondary nailing. Sequential secondary nailing, as defined, is done by protocol and is planned from the onset of treatment. The technique includes only a short period in the external fixator, a planned interval between removal of the frame and placement of the IM nail, and specific exclusion criteria. This technique essentially uses the external fixator as a temporary traction device while the soft tissue envelope is reconstructed. Reconstructive procedures, as defined, are not done by protocol and not planned from the onset of treatment. Patients are usually in the external fixator for extended periods of time. The indications are variable and include delayed union, nonunion, malunion, and infected nonunion. The authors conclude that when done by protocol sequential IM nailing is safe and effective. Reconstructive IM nailing, however, has strict contraindications that include: a history of or an active infection of the pin tract, wound, or bone; the presence of an open wound or pin tract; and the presence of a ring or halo sequestrum. Yet reconstructive secondary procedures can be effective in healthy individuals if the soft tissue envelope is completely reestablished, if antibiotics are administered preoperatively, and the nail is placed without reaming.

Adult↗
PubMed2000

External fixation in forearm shaft fractures.

External fixation for uncomplicated forearm fractures is rarely performed. The situation is different in a multiply injured patient or in a fracture with considerable soft tissue damage. In these cases the external fixator confers quick and efficient stabilisation which meets the requirements of adequate nursing and aids recovery of the general and local condition. Later change to an appropriate internal fixation procedure for definitive fracture treatment is recommended.

Adolescent↗
PubMed2004

External fixation of Charcot arthropathy.

Deformity, instability, and ulceration are present in a high percentage of patients who have Charcot arthropathy. Traditional treatment of these conditions has consisted of debridement, antibiotics, and immobilization with limited weight bearing. These measures are followed by long-term use of various foot and ankle bracing devices, such as the CROW walker, double metal upright, and the lined clam shell AFO with accommodative footwear either incorporated or attached. Sometimes these conservative measures fail and surgery is indicated for foot and ankle deformities with: (1) unbraceable deformity; (2) recurrent ulceration secondary to deformity, instability, or both; and (3) Charcot arthropathy with pain that is unresponsive to conservative measures. Certain acute traumatic situations with impending deformity also may benefit from early surgical stabilization. High deep infection rates (25%) have been reported in surgical reconstruction of feet that have a history of ulceration. The high rates of infection with internal fixation techniques and improved external fixation devices have led surgeons to consider external fixation as a viable alternative for: (1) singlestage correction of a limb with recent or current ulceration; (2) revision or salvage of previously reconstructed limbs; and (3) acute treatment of insufficiency type fractures (impending Charcot arthropathy) in the diabetic who has severe peripheral neuropathy with or without adjuvant internal fixation.

Arthropathy, Neurogenic↗
PubMed1993

Dynamic external fixation of distal radius fractures.

External fixation in fractures of the distal radius has been used for almost 80 years. The main objective is to achieve reduction and maintain the reduction throughout treatment. The fixator concept described as the dynamic fixator allows reduction in three planes and allows for the wrist to move after a period of rigid fixation. Fixator application is illustrated for fractures that necessitate bridging of the wrist joint and for extra-articular fractures. Indications for additional measures, including bone grafting, k-wire fixation, and stabilization of the radioulnar joint, are discussed. Associated injuries and postoperative management is described. The technique of correcting malunited fractures with the assistance of an external fixator is explained, with special emphasis on the correction of radial length, angle, and shift. The results of initial trials show a low complication rate and indicate that bone grafting should probably be used more than previously recommended.

Bone Screws↗
PubMed2002

[Tensile strength of bone fixation of hydroxyapatite coated Schanz screws of the Heidelberg External Fixation System (HEFS)--comparative torque measurements in clinical use and in cadaver tibia].

It is claimed in the literature that hydroxyapatite(HA)-coated screws of external fixators have superior fixation strength in bone, which is postulated to lead to a substantial decrease in loosening and infection rates. We report on a study of the maximum torque values developed while inserting and removing 30 HA-coated Schanz screws of 8 Heidelberg external fixation systems applied to the tibia to correct leg length differences and axial deformities. The infection rate was determined in accordance with defined criteria, and was found to be about 20% for the HA-coated screws. Screws without infection showed an extraction torque above insertion torque, screws with infection an extraction torque below. A significant correlation (p = 0.05) was seen between infection and decrease in fixation strength (quotient: loosening torque/tightening torque). To exclude the impact of such biological processes as osteointegration and bone remodelling, the clinical results were compared with the torques measured for coated and uncoated Schanz screws in a human cadaveric tibia. A significantly higher fixation strength in bone was found for HA-coated screws in comparison with uncoated screws (p = 0.002). These data warrant a clinical study directly comparing HA-coated and uncoated Schanz screws.

Bone Remodeling↗
PubMed1983

Stress-protection after external fixation on the intact rabbit tibia.

Bone loss due to the stress-protecting effect of a metal plate on intact bone is a well-known phenomenon. The purpose of the present study was to find whether a similar effect is caused by external fixation. External mini-fixation was applied on the intact rabbit tibial diaphysis of one leg. The other tibia served as control. The animals were sacrificed after 6 or 12 weeks, and both tibiae biomechanically tested in three-point bending. The bone mineral content was measured by photon absorptiometry. No significant changes in bone strength, stiffness or mineral content were found after 6 weeks. The strength and stiffness were significantly reduced after 12 weeks. The median strength and stiffness at that time were 87 and 88 per cent, respectively, in relation to the control bones. The mineral content in the bone segment which had been stabilized by external fixation was significantly reduced after 12 weeks (median 90 per cent of the values for the control bones). No significant change in the mineral content occurred at a level in the tibial diaphysis distal to the external fixation device. It is concluded that the stress-protecting effect caused by external mini-fixation on the rabbit tibia occurs later, and is less pronounced, than that caused by metal plates.

Animals↗
PubMed1993

Analysis of the external fixator pin-bone interface.

External fixator pins were inserted into tibiae of dogs under four in vivo loading conditions to examine the mechanism of pin loosening. Pins were quantitatively measured for pin torque resistance, and the pin tracts were studied radiographically and histologically. The pins holding an unstable fracture had more gross pin loosening. Pins also may become loose under static loads. Radiographic lucency of 1 mm or more in the cortical bone around a pin was evidence of gross pin loosening. Histologic examination showed that tight pin tracts were characterized by a lack of bone remodeling. Loose pin tracts were characterized by extensive bone resorption and inflammatory infiltrates. Pin loosening can be detected radiographically. Pin insertion technique is important to improve the initial pin torque resistance to minimize pin loosening. Sixty-nine percent of pins with an initial torque resistance of less than 68 Ncm became grossly loose compared with only 9% of pins with an initial torque resistance greater than 68 Ncm, regardless of the experimental group. Unstable external fracture fixation is another important factor in producing pin loosening. Pins loaded under unstable fracture fixation had the highest incidence of gross loosening. When applying an external fixator, the fracture rigidity should be critically evaluated and, if necessary, protected weight bearing must be introduced initially to minimize pin loosening.

Animals↗
PubMed1994

Three-dimensional dynamic AO external fixation of distal radial fractures--a preliminary report.

External fixation of unstable and intra-articular distal radial fractures has become increasingly popular. Dynamic external fixation, allowing movement of the wrist during the fixation period, is a relatively new approach which may further improve functional end results. To permit early functional treatment, the small AO external fixator was supplemented by a joint allowing all three degrees of rotational freedom. The centre of rotation is located at a point outside the device and lies approximately in the head of the capitate. With the natural centre of wrist rotation coincident with that of the fixator, admissable movements of the wrist include both flexion-extension and radio-ulnar deviation, without threatening fracture reduction. In vitro testing and initial clinical experience with a prototype are encouraging. Several improvements of the original design have been made and a multicentric clinical study is scheduled for further evaluation of the new dynamic external fixator.

Adult↗
PubMed1993

External fixation for open fractures of the upper extremity.

Recent advances in external fixation hardware, frame application, and pin-site care have resulted in the evolution of external fixation as a safe and versatile technique. It provides skeletal stability, access to the site of injury, and allows early mobilization. It avoids the disadvantages of additional soft-tissue stripping and the foreign body introduction associated with internal fixation of open fractures. The utility of external fixation principles in open hand and wrist fractures is well established. Indications for external fixation in open fractures of the forearm, elbow, and arm are more restricted. External fixation in these locations should probably be limited to situations of marked fracture comminution, bone loss, or extensive soft-tissue damage.

Arm Injuries↗
PubMed1985

Immediate external fixation of unstable pelvic fractures.

Immediate external fixation has been proposed as a means of stabilizing severe pelvic fractures to reduce the chance of organ failure and death. Sixty-six patients were admitted from January 1980 through December 1983 with double fractures of the pelvic ring that involved the posterior elements. Twenty-six patients (39 percent) underwent immediate external fixation for instability, and 40 patients (61 percent) with stable fractures were treated with bed rest. The two groups were similar in age, injury severity score, and degree of shock. The mortality rate of the two groups was the same (12 percent), as was the incidence of organ failure. The mean transfusion requirement in the unstable group was greater, but not significantly. Our results were better than those reported in recent studies in which immediate rigid fixation was not used. We conclude that the patient with multiple trauma without unstable pelvic fracture should undergo immediate external fixation to decrease morbidity and mortality rates and limit soft tissue damage.

Adult↗
PubMed2001

[Progressive limb lengthening with a centromedullary nail versus an external fixator: experimental study in sheep].

PURPOSE OF THE STUDY: Progressive limb lengthening with an external fixator often leads to pin-related complications. A new technique allowing progressive lengthening with a centromedullary nail without external fixation has been developed. This original double-locked device consists of matching male and female components fitted with a continuous thread. Lengthening is achieved via a one-way ratchet system. Twelve back-and-forth movements produce 1.25 mm lengthening. MATERIAL AND METHODS: We tested this new device on 20 sheep and compared results with external fixation lengthening in 20 other sheep. The animals were divided into groups for sacrifice on days 5, 10, 20, 45 and 90. Serial x-ray were obtained for all animals. In the 45-day and 90-day groups, histomorphometric (trichrome goldner coloration and polarized light microscopy) and densitometric studies were also performed. Bone mineral density (BMD) was determined and bone trabecular density (BTD) and trabecular bone volume (TBV) were expressed in percent of bone trabecular surface area. RESULTS: Mean lengthening in the 45-day and 90-day groups was 39 mm for the nail and 20 mm for external fixation (1 mm/day). At 90 days, 3 sheep out of 4 had consolidated radiologically with external fixation and 2 out of 4 with the nail. BMD was slightly better for external fixation (0.811 vs 0.695/cm(2)). This difference could probably be attributed to the greater lengthening obtained with the nail. At 45 days, BMD was the same (0.6 g/cm(2)) for both devices. BTD was nearly two-fold higher for the nail compared with external fixation (59.65% vs 32.61% at 90 days), most probably due to primary bone formation. The histomorphometric study allowed an analysis of the osteoid border. Bone quality obtained in the bone regenerate with the nail was superior to that obtained with external fixation. Primary bone formation resulted from membrane ossification with direct transformation of fibroblasts into osteoblasts. CONCLUSION: This work demonstrated that progressive lengthening can be achieved with a specifically designed centromedullary nail without iterative opening of the operative site. Tolerance to this type of device and quality of the bone regenerate are altogether satisfactory.

Absorptiometry, Photon↗
PubMed2001

[Strain gauge measurements on a one-side external fixation: a prospective series of 11 tibial shaft fractures].

PURPOSE OF THE STUDY: External fixation is often the treatment of choice for open complex fractures of the tibia. For closed tibial shaft fractures, it is generally a second choice alternative. The purpose of this study was to determine whether fusion of closed and open fractures of the tibia can be successfully achieved with a one-side external fixator equipped with strain gauges and to evaluate complications of this type of treatment. MATERIAL AND METHODS: A consecutive series of 11 mid shaft fractures of the tibia (4 closed fractures and 7 Gustilo grade I and II open fractures) in 11 patients (mean age 29 years) were treated with a one-side external fixator. Strain was measured weekly to adjust the treatment. A Sarmiento walking cast was applied in all cases 4 weeks after removal of the external fixator. RESULTS: All 11 fractures healed without complications and without pin tract infection. Mean delay to consolidation was 20.5 weeks (range 13 - 29.5 weeks). One patient required a revision procedure for decortication and bone graft at 12 weeks. Weight bearing (50% of body weight on the injured limb) was achieved at 6.7 weeks (mean) and total weight bearing at 11.9 weeks. The external fixator's strain curves were compatible with normal healing in 3 cases, with slow healing in 3 and with retarded healing in 3 others. Two of the curves did not show recognizable patterns despite a favorable clinical and radiological course to healing. DISCUSSION: Early detection of a pathological pattern of fracture healing followed with a strain gauge enabled adaptation of treatment in all cases. Decortication with bone grafting was necessary in one patient. In two other cases, compression of the fracture with the external fixator or dynamic locking were sufficient to achieve a favorable healing pattern. This small series demonstrated that bone healing can be achieved within usual delays with external fixation and without major complications. Use of strain gauges on the external fixator allowed early detection of retarded healing and subsequent modification of the treatment protocol. This type of treatment might be an interesting therapeutic alternative for the treatment of closed fractures of the tibial shaft.

Adult↗
PubMed2001

Influence of an interdental full pin on stability of an acrylic external fixator for rostral mandibular fractures in dogs.

OBJECTIVE: To determine total stiffness and gap stiffness of an external fixation system in a canine mandibular fracture gap model incorporating a full interdental pin as the only point of rostral fixation in a bilateral type-I external fixator. SAMPLE POPULATION: 10 canine mandibles. PROCEDURE: Bilateral mandibular ostectomies were performed between premolars 3 and 4. A type-I external fixator incorporating a full interdental pin was placed to stabilize a 0.5-cm fracture gap. Four pin configurations (intact mandibular bodies with fixator; ostectomized mandibular bodies and complete fixator; ostectomized mandibular bodies with caudal pins of rostral fragment cut; ostectomized mandibular bodies with all pins of rostral fragment cut) were tested in dorsoventral bending 5 times on each mandible. The full interdental pin remained intact in all configurations. Total stiffness and gap stiffness were determined for each configuration on a materials testing machine. RESULTS: Total stiffness of intact mandibles was significantly greater than that of ostectomized mandibles, regardless of external fixator configuration. However, total stiffness and gap stiffness were not significantly different among different external fixator configurations applied to ostectomized mandibles. CONCLUSION AND CLINICAL RELEVANCE: External fixator configurations with only the full interdental pin engaging the rostral fragment were as stiff as configurations that had 2 or 4 additional pins in the rostral fragment for the applied loads. External fixators for rostral mandibular fractures may be rigidly secured with rostral fragment implants applied extracortically, avoiding iatrogenic trauma to teeth and tooth roots.

Animals↗
PubMed1992

Treatment of hand injuries by external fixation.

Thirty-five consecutive applications of external fixation to the hand, including 27 acute cases and 8 reconstructive procedures, were studied. In both settings, external fixation was used not only for skeletal stabilization but also for management of the soft tissues. Twenty of the 22 acute fractures healed, and six arthrodeses with interposition bone grafts resulted in fusion. Three septic nonunions resolved, and two united successfully. There were no complications. We recommend external fixation systems in the hand, and several case reports are included in the study to illustrate the various applications.

Adolescent↗
PubMed1996

Pearls and pitfalls of deformity correction and limb lengthening via monolateral external fixation.

In conclusion, monolateral external fixation can be effectively utilized in the management of limb length discrepancy and angular deformity. This manuscript outlines the pertinent theory, application and problems important in these cases. When faced with specific congenital conditions the surgeon is encouraged to reference relevant literature that is more focused than the current paper.

Biomechanical Phenomena↗
PubMed1984

[Rare indications for an external fixator].

Seldom indications for the use of external fixator are reported and illustrated. As a rule the damage to the pelvis is complex and it is often associated with a polytrauma; unstable pelvis injuries in some cases can be stabilised by external fixator by the method of Slätis. Examples of osteotaxis are given for the treatment of comminuted fractures or defect-pseudarthroses or after osteomyelitic bone damage of femur and humerus. In the treatment of multi-fragment fractures of the base of the radius and of the forearm the external fixation can also be used with good success. The external mini-fixator is a new way for external stabilization in hand surgery and can provide good results in comminuted fractures of the fingers and for finger-replantation.

Adolescent↗