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PubMed2002

Unstable distal radial fractures treated by external fixation: an analytical review.

A "Hoffman type 2" external fixator was applied in 33 patients being treated for distal radial fractures that were classified according to the three basic types of the AO/ASIF system. Thirty fractures were suitable for statistical evaluation. Fixators were used alone (n = 10) or in combination with internal fixation of the intra-articular component. Fixators were removed sooner when they were combined with internal devices and these patients had significantly less pain. There was no relation between pain, classification, primary displacement, function, position on the radiograph, and Green and O'Brien score. Primary displacement was more important in patients over 50 years of age. Reflex sympathetic dystrophy was associated with fractures of the ulnar head. Ulnar styloid fractures were not related to increased laxity or symptoms at the distal radioulnar joint. There were no signs of intracarpal "instability" in patients less than 50 years of age and the condition caused no specific symptoms. Maintenance of stability was better when grafts were used, but not significantly so. Green and O'Brien scoring was no more informative than a simple ordinal pain ranking system.

Adult↗
PubMed1994

Biomechanics of radiotransparent circular external fixators.

The mechanical and biomechanical characteristics of an external fixation system determine the biologic environment of the treated site. Traditionally, the Ilizarov system uses steel rings, which are heavy and can interfere with radiographic imaging. Biomechanical comparison of the traditional Ilizarov steel rings with rings made of oriented carbon fibers shows that the mechanical characteristics of the carbon fiber rings are comparable with those exhibited by traditional steel rings, being elastically rigid over the whole range of loads applied (147 N, 441 N, 735 N, 1029 N, 1110.34 N, 1192.7 N, 1274 N, 1355.3 N, 1437.7 N, 1519 N, and 1600.4 N). The plastic deformation exhibited by steel rings at high loads thus is avoided. In a clinical situation, such a deformation in response to loading would alter the biomechanics of the fracture site, possibly affecting the healing process.

Biomechanical Phenomena↗
PubMed2000

The anterior T-frame external fixator for high-energy proximal tibial fractures.

The authors' experience using anterior T-frame external fixation combined with percutaneous internal fixation for treatment of high-energy proximal tibial fractures is reported. Thirty-six patients (38 fractures) were reviewed who were treated during a consecutive 42-month period. Three patients died and one patient had an amputation for a Type IIIC open injury, leaving 20 males and 12 females with 21 closed and 13 open fractures (two Type II, seven Type IIIA, three Type IIIB, and one Type IIIC). The average followup was 26 months. Fractures united at a mean of 20 weeks. Ten secondary surgical procedures were planned, including seven antibiotic bead removals with autogenous bone grafting and three soft tissue coverage procedures. Nine (26%) complications were found, including one deep infection (septic arthritis) and three pin tract infections, and one each malunion, nonunion, refracture, knee stiffness requiring manipulation under anesthesia, and deep venous thrombosis. The average Knee Society score was 85 for pain and 83 for function. All patients achieved full knee extension and mean flexion was 125 degrees. The anterior T-frame external fixator with percutaneous internal fixation is a reliable method to stabilize these injuries. It is simple, inexpensive, and effective.

Adolescent↗
PubMedDate not supplied

Cortex distraction forces caused by the insertion of external fixator pins.

OBJECTIVE: Insertion of a bicortical threaded external fixator pin can cause bone damage. An unexpected crack can propagate along the bone when the pin touches the far cortex. The objective of this study was to investigate whether drilling and inserting bicortical pins into the shafts of long bones can cause large distraction forces to be generated between the cortices. DESIGN: Two flat samples of bone or bone substitute (Tufnol) were mounted parallel at each end of a specially designed force measurement column. Three common pin designs were inserted into the samples: tapered, self-threading and self-drilling, and self-threading pins. The axial thrust and the cortex distraction force between the two samples were measured as the pins were inserted. RESULTS: High distraction forces were measured between the cortices for all pin designs, typically 700 to 1,000 Newtons. CONCLUSIONS: The clinical significance of these findings is that the insertion of bicortical pins of the designs tested may generate a large distraction force between the cortices. This may drive a fracture apart or propagate an undisplaced fracture. Therefore, care must be taken to ensure that bicortical pins are inserted in locations free of local defects.

Bone Nails↗
PubMed1983

External fixation for pedicle-flap immobilization: a new method providing limited motion.

The external fixater has proven to be an effective method of providing immobilization in pedicle-flap surgery. In certain instances, when the pedicle will permit some degree of mobility, limited-motion fixation eliminates the common disadvantages of rigid fixation. On this basis, we recommend the use of a ball-joint adapter in conjunction with the external fixater for certain types of pedicle-flap immobilization.

Child↗
PubMed1995

[Treatment of radius fractures with a newly developed dynamic external fixator].

Ligamentotaxis first described by Vidal presented the opportunity to treat wrist fractures near to the joint with external fixation. The first published results with this technique were surprisingly successful. As a result, since 1980 the author began, as one of the first in the German speaking regions, to treat radius fractures with the Hoffmann C-series external fixator. With a newly developed dynamic wrist fixator device 4 clinics have treated 104 fractures in a prospective study. These fractures were followed up 6 months later. Using the Lidström classification, the x-ray results were very good and good for 98% and moderate for 2% of treated fractures. Clinically the results were very good and good for 91% and moderate for 2% of treated fractures. Poor results were not recorded. 92% of the patients had a shortening of the radius of less than 2 mm. The sooner motion was initiated, the better the results were during the follow up. All the parameters such as x-ray evaluation, clinical evaluation, pain, strength, and in particular motion were improved when compared to a static fixator or motion after 14 postoperative days. The treatment time with this new dynamic wrist fixator device was reduced by two weeks compared to a static fixator. Cancellous bone grafting was never necessary.

Equipment Design↗
PubMed2002

False aneurysm of perforating branch of the profunda femoris artery after external fixation for a complicated femur fracture.

False aneurysm of the profunda femoris artery rarely occurs and is a serious complication following femur fracture. A 39-year-old man who developed a false aneurysm arising from the perforating branch of the profunda femoris artery following an external fixation for a complicated femur fracture was presented. Clinical diagnosis was confirmed by selective arterial angiography after occurrence of significant hemorrhage and swelling of the injured thigh. The false aneurysm was treated by ligation of the perforating branch of the profunda femoris artery and excision of the aneurysmal sac via the medial approach. Clinical status of the patient was uneventful postoperatively. The right thigh swelling decreased rapidly following the operation in 1 week. The patient was discharged on the 10th postoperative day with external fixation. False aneurysm in a branch of the profunda femoris artery is a very rare status following application of the external fixator due to complicated femur fracture. Related literatures and interventions were reviewed on the basis of this case.

Adult↗
PubMed1994

Load transmission through the callus site with external fixation systems: theoretical and experimental analysis.

The fracture callus contribution to the total rigidity of external fixator-fractured bone element was analysed. This study was achieved from both theoretical and experimental perspectives. The theoretical study was done using the finite element method with a three-dimensional model. In this model, both the callus and the development of its elastic characteristics were considered. A series of 38 New Zealand-California white rabbits with tibial fractures treated with some external fixation system was used in this study. Such devices could reproduce either rigid or elastic features. The frame dynamization can be obtained at different fracture healing stages. Animals were classified into four series: (1) rigid fixators, (2) dynamized fixators two weeks after surgery, (3) three weeks after surgery and (4) four weeks after surgery. Tension tests were performed to evaluate callus strength. Theoretical results showed significant levels of callus load transmission (85.5%) when the callus elastic modulus is 1/100 of the elastic modulus of intact bone in an external fixator with rigid features. Experimental analysis of the callus obtained with different external fixator systems did not show differences among them. This fact implies that the immature callus theoretically modelled (E = 100 N mm-2) appears early in the rabbit fracture model (before two weeks, when first dynamization was made), for this reason no differences were found between the two types of treatment (rigid and dynamized systems). This fact questions the reliability of the dynamization process in external fixation of fractures and it implies accurate investigations in the clinical field.

Animals↗
PubMed2006

[Use of Hoffman external fixation for extra-articular upper metaphysealtibial fractures].

Treatment of extra-articular upper metaphyseal tibial fractures can be difficult. Orthopedic treatment is frequently complicated by second displacement These fractures are inappropriate for locked intra-medullary nailing because of the shorteness of the proximal extremity. Damages of soft tissues. frequently associated with these factures, expose internal osteosynthesis to many risks. For these reasons, we opted for external fixation. Our study was a retrospective analysis of 46 extra-articular metaphyseal tibial fractures treated by external fixation with Hoffman material. The average follow-up was 24 months. Consolidation was obtained within 4 months in average. Septic complications. inherent to the method were uncommon or minor. Functional results were satisfactory in 84% of cases. So, external fixation with Hoffman material. with particular recommandations, is a promising method for the treatment of extra-articular of proximal metaphyseal tibial fractures.

Adult↗
PubMed2006

Hybrid external fixation in periarticular tibial fractures. Good final outcome in 56 patients.

Out of 65 patients with periarticular fractures of the tibia treated by use of hybrid external fixation (a combination of indigenously manufactured version of ring and AO tubular fixator) from February 1997 to October 2003, 56 cases were taken up for this study with a minimum follow-up of 12 months. The injury was due to a high-velocity motor vehicle accident in 49 and a fall in 7 patients. Thirty five were tibial plateau fractures and 21 were distal tibial plafond fractures. Forty eight were compound fractures and eight were closed. They were treated by debridement (48 compound) and hybrid external fixator (n = 56). All the patients were assessed clinically and radiographically for an average follow-up of 42.5 months (range: 12 to 67). In tibial plateau fractures (n = 35), the final outcome was good to excellent in 30, fair in 2 and poor in 3. In tibial plafond fractures (n = 21), results were good to excellent in 16, fair in 3 and poor in 2. We recommend the use of hybrid external fixator for periarticular tibial fractures occurring due to high-energy trauma. In addition, rates of complications as seen with other modalities of fixation are greatly reduced. It facilitates adequate care of associated soft tissue injuries.

Adolescent↗
PubMed1985

The management of severely comminuted fractures of the femoral shaft, using the external fixator.

Fractures of the femoral shaft are often treated by an established method of internal fixation, such as a medullary nail or a plate and screws, to obviate the many disadvantages of traction and prolonged rest in bed. Fractures of the femoral shaft which are severely comminuted and open are usually unsuitable for internal fixation. Between July 1981 and March 1983 we treated seven patients with severely comminuted fractures of the femoral shaft (of which three were open), using the ASIF tubular external fixator system or the Wagner apparatus. The technique of application of the external fixator is important and is described. When correctly applied, the knee's movement was not restricted and few complications were experienced. All the fractures united within 8 months in a good position without shortening, and none required an additional operation. The use of the external fixator in these patients reduced their time in the hospital and facilitated their postoperative rehabilitation by allowing uncomplicated healing of a complicated fracture.

Adolescent↗
PubMed1995

Comparison of the mechanical performance of three types of external fixators: linear, circular and hybrid.

Different configurations of the Monticelli-Spinelli and Ilizarov external fixation systems were tested to define their mechanical properties. In five configurations the external fixator consisted of rings with tensioned wires (circular), while in one configuration two pairs of the tensioned wires and their correspondent ring were replaced by threaded pins (hybrid). Testing was performed in axial compression, bending and torsion. The results were compared to the characteristics of a selected linear fixator group. Both the circular and the hybrid configurations were non-linear in compression. In bending, circular fixators had a similar pattern in both anteroposterior and oblique loading directions. The bending load-displacement pattern for the hybrid fixators was similar to the linear fixators, higher stiffness in the plane of the pins. Torsion was linear for both circular and hybrid fixators, as for the linear fixators. By combination of wires and pins (hybrid configuration), the mechanical behaviour had characteristics from both linear and circular fixators. It is concluded that the three studied groups own different mechanical performance and can be considered as different types of fixators. While it has been demonstrated that osteogenesis can be achieved independently of the mechanical behaviour of the fixator, this study supports the suggestion that some complications can be related to the mechanical behaviour of the fixator.

Journal Article↗
PubMed2006

External fixation of pediatric femur fractures with cortical contact.

The cases of 40 pediatric femur fractures treated with external fixation were reviewed to determine whether stabilization with cortical contact resulted in clinical leg-length discrepancy (LLD). Mean follow-up was 29.4 months, mean age was 6.6 years (range, 2-10 years), 25 injuries were isolated, 100% of the fixators were applied with cortical contact, all fractures healed by a mean of 92 days, 72.5% were dynamized before removal, mean LLD was 0.24 cm short, and complications included 1 refracture (2.5%), early removal of 2 loose pins (1.25% of 160 pins), pin-tract infections in 21 patients (52.5%), and 1 LLD (2.5%) of more than 1.0 cm (5.0 cm short). External fixation with cortical contact was an effective treatment for pediatric femur fractures. It limited overgrowth and resulted in few refractures. Pin-tract infections were common.

Adolescent↗
PubMed1989

Biochemical changes in articular cartilage after joint immobilization by casting or external fixation.

Knees of mature dogs were immobilized for 6 weeks by long-leg casts allowing 8 degrees-15 degrees of motion, a model studied by others, or with external fixators, a new, more severe model that kept the joints rigid. Some animals were allowed to recover for 1 week after the immobilization period. Articular cartilage was examined histologically and biochemically. After 6 weeks of immobilization, water increased 7% in both casted and fixator-immobilized joints compared with normal knee cartilage, while hexuronic acid was 23 and 28% lower, respectively. The limited motion permitted by the casts resulted in a smaller depression of proteoglycan synthesis and less proteoglycan loss during immobilization than occurred in the rigid external fixator group. The protective effect of limited motion was shown clearly during the recovery period: as measured by hexuronic acid content, cartilage from the casted joints had almost recovered within 1 week, whereas the external fixator group experienced little or no recovery during the week after treatment. In contrast to previous studies by others with casted joints, both newly synthesized [35S]sulfate-labeled and accumulated unlabeled proteoglycans from both casted and fixator-immobilized cartilages were able to form complexes with exogenous hyaluronic acid to the same extent as those from control cartilage. Thus, in immobilized cartilage, failure of the newly synthesized proteoglycan to bind to hyaluronate is not a mechanism of accelerated proteoglycan loss. The accelerated proteoglycan turnover appears to be caused by a combination of decreased synthesis and increased proteolysis of the secreted proteoglycans.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Dynamic external fixation versus non-operative treatment of severe distal radial fractures.

Severe distal radius fractures often lead to impairment of wrist function, particularly in younger patients. This paper reports 55 consecutive patients younger than 65 years with displaced intra-articular fractures of the distal radius. Twenty-nine were treated with dynamic external fixation, and 26 with closed reduction and plaster cast immobilization. At least 1 year after the injury the anatomical and functional results were assessed using the scoring system of Lidstrom. In a retrospective analysis, both the anatomical and functional end score were significantly better in the dynamic external fixation group than in the group treated non-operatively (0.02 P < 0.05 using chi 2 analysis with Yates' correction). We conclude that dynamic external fixation is a good alternative for non-operative treatment in younger patients with severe distal radial fractures. Prospective evaluation of this subject is necessary.

External Fixators↗
PubMed1995

External fixation of intertrochanteric fractures of the femur.

Forty patients with intertrochanteric fractures of the femur were treated by external fixation between July 1992 and April 1994. They were selected because of their high surgical risk, and evaluated by radiographs immediately after operation, and at 30 and 90 days. The results indicate that external fixation is a useful method of treatment for this type of patient.

Adolescent↗
PubMed2000

Prevention of pin track infection in external fixation with silver coated pins: clinical and microbiological results.

Pin tract infection is a frequent complication of external fixation; according to literature its frequency ranges from 2-30%. The recent introduction of silver coating of polymeric materials was found to decrease bacterial adhesion; its clinical use with Foley catheters and central venous catheters led to significant results. To verify the ability of the same silver coating to decrease the bacterial colonization on external fixation screws, a prospective randomized study was carried out on 24 male patients; a total of 106 screws were implanted in the lower limb to fix femoral or tibial diaphyseal fractures: 50 were coated with silver and 56 were commercially available stainless steel screws. Although the coated screws resulted in a lower rate of positive cultures (30.0%) than the uncoated screws (42.9%), this difference was not statistically significant (p = 0.243). The clinical behavior of the coated screws did not differ from that of the uncoated ones. Furthermore, the implant of silver-coated screws resulted in a significant increase in the silver serum level. These results led us to consider it ethically unacceptable to continue this investigation.

Adolescent↗
PubMed2006

Experimental studies of lateral stress to transverse fractured femora treated with external fixation.

As part of a postmortem research project 9 beagle femora were dynamically tested by means of three-point bending. The test device was a spring driven impactor with an impact velocity of 3 m/s. Maximum bending force, deflection and force-deflection history were documented. After the impact transverse fractures were observed in 6 specimens, while another 3 specimens showed short oblique fractures. The fractured femora were treated realistically with external fixation (triax monotube) and again loaded on the impactor. After this treatment of the specimens and dynamic loading comminuted fractures occurred. In 7 cases all 4 pins were distorted. While there was only a small difference between the mean bending force of 751.01 N before and 729.54 N after treatment, a significant difference in terms of deflection and bending stiffness showed with p = 0.0039 for both parameters. This experimental result means that in cases of transverse fractures caused by ventral force only 9.6 % of the initial bending stiffness is obtained after stabilization with external fixation. Considering the fact that the use of external fixation protracts the time to bone consolidation of transverse fractures, this method cannot be designed as the therapy of choice.

Animals↗