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At least 1,099 records · Page 61Linked to original sources
PubMed1992

External fixation of unstable metacarpal and phalangeal fractures.

A prospective study of the management of 30 patients with 37 unstable or complex metacarpal or phalangeal fractures treated with the "Shearer" micro-external fixator was carried out over an 18-month period. The stability achieved, with minimal soft-tissue tethering, allowed early joint mobilisation with good or excellent function in 94% of metacarpal and 85% of phalangeal fractures by nine weeks. There were no cases of non-union and few complications.

Equipment Design↗
PubMed2004

External fixation versus locked intramedullary nailing in tibial shaft fractures: a prospective, randomised study of 78 patients.

INTRODUCTION: We performed a prospective, randomised study to compare the Ex-fi-re external fixator (EF) with locked intramedullary (IM) nailing in tibial fractures. Only fractures without soft-tissue problems of importance were included. MATERIALS AND METHODS: Ex-fi-re is a unilateral, dynamic axial fixator with fracture reduction capabilities. The Grosse-Kempf nail was used for nailing. A total of 78 patients with 79 fractures were entered in the study (41 Ex-fi-re, 38 IM nails). RESULTS: Time to radiographic union and full weight-bearing did not differ significantly, but unprotected weight-bearing was achieved earlier in the IM group (12 vs 20 weeks; p<0.001). There were more reoperations due to secondary dislocation in the EF group. There were no differences in final angulation or shortening. After 6 months and 1 year there were no differences in knee motion, ankle motion, fracture site pain or ankle pain. Some 64% of the nailed patients complained of anterior knee pain after 1 year. CONCLUSION: The results were comparable in most respects. Unprotected weight-bearing was achieved earlier after IM nailing. Anterior knee pain was frequent after nailing.

Adolescent↗
PubMed1999

[New concepts of monitoring and assessment of bone union stiffness in fractures treated by Dynastab DK external fixation].

This paper focuses on heuristic techniques based on artificial intelligence namely artificial non-linear and multilayer neurons employed for assessment of bone union in fractures treated by Dynastab DK external fixation. The software used allowed for prediction of bone union curve at the early stage of treatment. The training of the neural net has been done on the ground of 56 cases of Dynastab DK treated fractures. The net served for periodical assessment of bone union and its further prediction in 17 long bone shaft fractures. Bone mechanical properties at the fracture site showed non-linear changes in time. Specifically great changes were noted 4 months postoperatively. Flexion at the fracture site is critical. Neuron net proved to be useful in predicting bone union curve.

Bone Regeneration↗
PubMed1993

External fixator pin placement in the forearm: how safe is it? An anatomical study.

An anatomical study was undertaken using cadaveric forearms to identify the best technique and angle of pin placement for external fixator pins. We have found that inserting pins through stab incisions risks transfixion of the underlying structures and leads to an increased morbidity. We conclude that inserting pins under direct vision is much safer and that the optimum angle of pin insertion is in the coronal plane, parallel to the plane of the metacarpals.

Bone Nails↗
PubMed2003

A reliable externally fixated murine femoral fracture model that accounts for variation in movement between animals.

Fifty-two CFLP mice had an open femoral diaphyseal osteotomy held in compression by a four-pin external fixator. The movement of 34 of the mice in their cages was quantified before and after operation, until sacrifice at 4, 8, 16 or 24 days. Thirty-three specimens underwent histomorphometric analysis and 19 specimens underwent torsional stiffness measurement. The expected combination of intramembranous and endochondral bone formation was observed, and the model was shown to be reliable in that variation in the histological parameters of healing was small between animals at the same time point, compared to the variation between time-points. There was surprisingly large individual variation in the amount of animal movement about the cage, which correlated with both histomorphometric and mechanical measures of healing. Animals that moved more had larger external calluses containing more cartilage and demonstrated lower torsional stiffness at the same time point. Assuming that movement of the whole animal predicts, at least to some extent, movement at the fracture site, this correlation is what would be expected in a model that involves similar processes to those in human fracture healing. Models such as this, employed to determine the effect of experimental interventions, will yield more information if the natural variation in animal motion is measured and included in the analysis.

Animals↗
PubMed1989

The effect of external fixation stiffness on early healing of transverse osteotomies.

The effect of bending stiffness of external fixators on the early healing of transverse tibial osteotomies was studied in a canine model to determine whether there is a particular range of fixation stiffness where healing is poor. Five unilateral fixators with different stiffnesses were developed and employed along with a dynamic compression plate to fix experimental osteotomies of dog tibias and the contralateral intact tibias served as controls. The six experimental fixation devices were: plate (P), stainless steel sidebar fixator (SS), stiff aluminum sidebar fixator (SA), intermediate aluminum sidebar fixator (IA), flexible aluminum sidebar fixator (FA), and Delrin sidebar fixator (D). Compared with human tibial fixation methods, the fixators ranged from a rigidity greater than a plate on a human tibia to a flexibility similar to a plaster cast on a human lower leg. Sixty-four adult male mongrel dogs (29 +/- 3 kg) underwent surgery and 52 completed the 9-week study, leaving 7 to 10 dogs in each experimental group (P = 8, SS = 7, SA = 9, IA = 9, FA = 10, D = 9). After the 9-week survival period the experimental tibias were radiographed and callus area was digitized. Both the experimental and control tibias were then tested to failure in four-point bending, and failure moment, stiffness, and energy to failure were determined. Of the 52 osteotomies, only four developed nonunions: 3 of 10 in the FA group and 1 of 7 in the SS group. Using analysis of variance, no statistical differences were detected in failure force, stiffness, or energy to failure as a function of fixator groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Experimental analysis of Hoffmann external fixation in various mountings.

The mechanical properties of four different configurations of the Hoffmann external fixation system were tested in an experimental setup using 4-mm stainless steel pins. Furthermore, stainless-steel pins and titanium pins 5 mm in diameter were applied in one of the fixators. The evaluation of the results was based on a paired t-test, with P less than 0.05 as the significance level. The quadrilateral transfixing Hoffmann-Vidal frame (HVF) proved to be the most rigid fixator under all loading conditions. The unilateral frame type supplied with two connecting bars and four ball joints was significantly more rigid than the unilateral single-bar device. By increasing the pin diameter from 4 to 5 mm a further increase of stiffness could be achieved, thus reaching about two-thirds of the rigidity of the HVF. The difference between titanium and stainless steel pins was not significant. Common for all the frame mountings was a fivefold greater rigidity in the lateral direction (in the plane of the pins) than in the anteroposterior direction (perpendicular to the pins).

Biomechanical Phenomena↗
PubMed1993

Pin-hole shear stresses generated by conical and standard external fixation pins.

Pin-hole shear stresses generated by tapered (conical) and untapered (standard) external fixator pins were compared using a photoelastic technique. The results show that shear stresses progressively increase as a conical pin is inserted but remain the same for the standard pin irrespective of the depth of insertion.

Bone Nails↗
PubMedDate not supplied

An experimental model to measure the torque of pin insertion and extraction for external fixation.

An original system used to measure torque of pin insertion and extraction in external fixation is presented. The system is made up of an electronic dynamometric key and an analogic/digital switchboard that may be linked up to a personal computer. The in vitro results show the simplicity of use and the versatility of the system, that is capable of providing the surgeon with accurate indicative values as to the mechanical resistance of the bone-pin interface during implantation of any fixator.

Biomechanical Phenomena↗
PubMed2002

The effects of dynamization and destabilization of the external fixator on fracture healing: a comparative biomechanical study in dogs.

This study compared the effects of axial dynamization and staged destabilization on fracture healing. Bilateral midshafts of canine tibiae were osteotomized and fixed with an external fixator. The hind limbs were divided into two groups: the destabilized group in which the fixator's stiffness was progressively reduced over time and the axially dynamized group in which the fixator was axially dynamized. The healed tibiae were tested for 3-point bending in the anteroposterior plane. The biomechanical tests performed 2 months postoperatively revealed that the side with the destabilized fixator was more rigid than the side with the axially dynamized fixator, but the differences were insignificant (P=.20). This study showed staged destabilization of the fixator's stiffness was as effective on the enhancement of fracture healing as axial dynamization.

Animals↗
PubMed1991

External fixation for comminuted intra-articular wrist fractures.

We treated 101 consecutive patients with Frykman type III, IV, VII and VIII fractures of the distal radius and ulna with the small Hoffman external fixator between 1986 and 1989. All patients were reviewed after a mean follow-up period of 22 months (range: 12 to 45 months). At follow-up, 88 wrists (87%) were rated good or excellent, according to the demerit point system, and 13 wrists (13%) were rated fair or poor according to the same system. A highly significant correlation (p less than 0.01) was found between the overall scores at follow-up and the grade of postoperative articular incongruity, between the overall scores and the grade of osteoarthritis at follow-up, between the grade of postoperative articular incongruity and the grade of osteoarthritis at the follow-up, as well as between the overall scores and the grip strength at follow-up. A significant correlation (p less than 0.05) was found between the length of follow-up and the grade of osteoarthritis at follow-up. Although the complication rate was rather high (40%), most of these problems were minor, transient and pin-related.

Adolescent↗
PubMed2001

High tibial osteotomy using a dynamic axial external fixator.

High tibial osteotomy is an accepted treatment for unicompartmental osteoarthritis of the knee. Conventional osteotomy can be a demanding procedure with potential for complications. Opening wedge high tibial osteotomy using an external fixator is an alternative that may have advantages in comparison with classic methods. The aims of the current study were to determine if opening wedge osteotomy using hemicallotasis techniques is safer than, and the outcome comparable with that of, conventional techniques. Seventy-six high tibial osteotomies were performed in 65 patients for primary osteoarthritis. The mean age of the patients was 54.8 years (range, 36-70 years). The mean followup was 6 years. The only serious complication occurred in one patient, who had chronic osteomyelitis develop 2 years after surgery. There were no neurologic or vascular complications. The authors think this technique is safer than conventional techniques. Survivorship at 5 and 10 years was 89% and 63%, respectively. The mean knee score in osteotomies was 26.6 (maximum possible score, 48). The outcome is comparable with, or better than, that of other techniques for osteotomy. Subsequent knee replacement, in cases requiring conversion, was straightforward. The mean score in knees that had osteotomies that were converted to total knee replacements was 33.7.

Activities of Daily Living↗
PubMed2001

[Corrective osteotomy using Hoffmann II external fixators for extra-auricular malunion of the distal radius].

The authors present the technique and clinical results of a corrective osteotomy for malunion following extra-articular fractures of the distal radius. External fixation allows restoration of the length of the radius with minimal damage to the periosteum. It allows early mobilization of the radiocarpal joint. The position of the distal pins provides intraoperative visual control of the angular correction. The minimal invasive approach decreases the risk of iatrogenic lesion of an extensor tendon or a sensitive branch of the radial nerve. This technique is easy and reliable.

Adult↗
PubMed1999

Pin-tract complications in external fixation of fractures of the distal radius.

We analyzed retrospectively the rate and outcome of pin-tract complications in 314 unstable fractures of the distal radius, treated with the Hoffmann small-frame external fixator. The overall rate of complications was 27%. The commonest complication (21%) was pin-tract infection, which was treated with oral antibiotics. There were no cases of osteitis. Complications led to premature removal of the fixator in 17 of the cases. Women over the age of 75 years had a significantly higher rate of pin loosening (17%), but not a higher rate of premature removal of the fixator due to complications. 4% of the cases had a pin-site fracture, all women. The rate of pin-tract complications was high, but severe complications were rare, even in old women.

Adolescent↗
PubMedDate not supplied

Treatment of adolescent Blount disease with the circular external fixation device and distraction osteogenesis.

The purpose of this study was to review both the anatomic and functional results of treatment of adolescent tibia vara with distraction osteogenesis by using the circular external-fixation device. Twelve tibias in eight patients were treated. Preoperative proximal tibial varus averaged 18 degrees (range, 7-26 degrees). Postoperatively the mean deviation from standard anatomic alignment of the proximal tibia was 2.5 degrees (range, 0-7 degrees). All patients were allowed to weight bear as tolerated throughout the 12 weeks of frame wear. Function was assessed by knee score and was improved in all patients at a mean follow-up of 23 months. There were no neurovascular complications or delayed unions. One patient required return to the operating room because of premature consolidation of his regenerate.

Adolescent↗