Mini External Fixator Research Articles

Pin breakage in trapezio-lunate external fixation of scaphoid fractures

The treatment of scaphoid fracture is determined by the amount of fracture displacement and stability. All acceptable closed or open methods consist of long term immobilisation and secondary tissue damage. The trapezio-lunate mini external fixation for acute scaphoid fracture is a novel method which does not require any extra immobilization or secondary tissue damage. Two cases of trapezial-pin breakage in trapezio-lunate external fixation of scaphoid fractures which resulted in non-union are described. Careful manufacturing and clinical application are mandatory to avoid this previously undescribed complication.

Joshi's External Stabilization System (JESS): a simple mini external fixator for the management of hand trauma and its sequels: B.B. Joshi (Bombay, India)

Joshi's External Stabilization System (JESS): a simple mini external fixator for the management of hand trauma and its sequels: B.B. Joshi (Bombay, India)

The results of external fixation of the radius in the treatment of comminuted intraarticular fractures of the distal end

14 unstable comminuted intraarticular fractures of the distal radius were treated by the use of the A/O mini-external fixator. The distal pins were inserted in the distal fragment, thus leaving the wrist joint free to mobilize. Clinical results were assessed at 3 to 12 months using the Sarmiento demerit point system. Nine were male and five female, with a mean age of 37 years. Ten fractures were closed and four were open. 11 patients (78.5%) had an excellent functional score and three (21.5%) had a good score. All patients had normal wrist morphology with an average radial length of 11 mm, radial angle of 23° and a mean volar angle of 12°. 12 patients had anatomical radio-carpal and radio-uluar joints and two patients had a step less than 2 mm at the radio-carpal surface. This method has proved in our experience to be reliable in maintaining the position as well as allowing early functional recovery.

Congenital brachymetatarsia: three cases.

We report on three cases with congenital brachymetatarsia, one with bilateral affectation, together with the results of a lengthening of the short metatarsal bones by progressive axial distraction using an external minifixator. The method proved to be easy to implement, permitting immediate functionality of the ankle and early load bearing. The immediate results (cosmetic) and later findings (functional) were excellent in all three cases.

New Techniques of Osteosynthesis of the Hand. Principles, Clinical Applications and Biomechanics with Special Reference to External Minifixation.

New Techniques of Osteosynthesis of the Hand. Principles, Clinical Applications and Biomechanics with Special Reference to External Minifixation.

External Minifixation for Treatment of Closed Fractures of the Metacarpal Bones

External minifixators were used in the treatment of 63 closed diaphyseal metacarpal bone fractures. A simple half-frame configuration was applied in all the cases. Open reduction was performed in 26%. The mean duration of external fixation was 30 days. There were no cases of nonunion. Anatomical reduction was obtained in 86.6% of the cases. There were no cases of reflex sympathetic dystrophy. The general functional results were very good or good in 96.6%. Open reduction did not significantly alter the final results. External minifixation is usually accepted as a treatment of open metacarpal fractures. Because of the excellent results obtained in our series, we believe that the indications of external minifixation could be enlarged to closed metacarpal bone fractures.

The use of the Manuflex disposable mini external fixator.

The Manuflex mini external fixator is an original device which is suitable for either provisional or definitive fixation of hand or foot fractures. The system is simple, disposable, relatively radiolucent, and inexpensive. It has been tested in an animal laboratory and has been used successfully in 27 human cases.

In vitro effects of external fixation on intact and osteotomized tibiae. A biomechanical study.

In order to study the in vitro mechanical effects of external fixation on intact and osteotomized bone, human and rabbit tibiae were tested in three-point bending in an Instron testing machine. Intact tibiae were loaded in the elastic range before and after application of an external fixation device. In the human specimens the Vidal-Adrey double frame was used, and in the rabbit specimens the external mini-fixation. The bone deformation in the anteroposterior direction was measured with a linear voltage differential transformer. After application of external fixation a median bone elastic stiffness of 110.2 per cent in human tibiae and of 106.1 per cent in rabbit tibiae was found, in relation to the stiffness of intact tibiae without external fixation. The stiffness increase was significant in human specimens, but not significant in rabbit specimens. In osteotomized human tibiae fixed with the Vidal-Adrey double frame a median stiffness of 8.5 per cent of the stiffness of intact bones was found when compression was not applied, compared to 19.9 per cent when compression was applied. In rabbit tibiae a median stiffness of osteotomized bones with external mini-fixation was 8.9 per cent of the stiffness of intact bones. There was a good agreement between the results in rabbit tibiae with the mini-fixation and human tibiae with external fixation without compression. The external mini-fixation thus seems to be a suitable model for the study of bone healing in rabbit tibiae.

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.