DE4118303A1 - Bone fracture therapeutical instrument - is external frame with variable and measurable pressure and traction forces - Google Patents

Abstract

The external instrument gives dynamic axial loading and quantifiable traction or pressure forces are exerted on the interfragmentary areas by spring components (1). These components are either combined with or not with a damping component (2) in order e.g. to neutralise the wt. force of the patient on the interfragmentary area. Axially to the spring components and/or damping component, pressure measurement probes (3) can be applied in order to measure the interfragmentary traction or pressure forces. The spring and damping components fitted axially exert the traction or pressure force via solid, fluid or gas-form media. Pins or nails are used to fix such components in position to the fractured bone. USE - In orthopaedic practice, to treat fractures, pseudo-arthritis deformans, post-traumatic bone defects, and extension osteotomy cases.

Description

Genus of Subject of registration

The invention relates to an axially dynamic Fixa expensive external, where the interfragmentary printing and Tensile forces are quantifiable. The interfragmentary Push or pull forces are independent of the pressure or tensile forces, especially body weight.

State of the art

The use of the external fixator in bone treatment lung is widespread and indispensable. Because of the easier access routes and the easier appli cation, compared to the internal osteosynthesis, wins the external fixator has recently become increasingly important tung (e.g.: M. Zerna. R. Klenke, External fixator in the district hospital. Zentralbl-Chirurgie, P 1031-1040. 115 (16), 1900). With open fracture treatment is increasing mend the supply with the fixator externally as defini viewed and implemented. Furthermore, pseudoarthrosis, post-traumatic kno defects or extension osteotomies Ring fixators external or with a modular Pipe fixator system treated. It will print or Tractive forces via threaded rods or fine wires applied to the interfragmental area. (Boltze, W.-H .: The external fixator (pipe system). AO bulletin 1976 Official organ of the Swiss Arbeitsge Society for Osteosynthesis Questions, Ilizarov, G .: collective band of the Orthopedic Society, p. 146, 1954, Kurgan, A. Rüter, R. Brutscher: The treatment of extensive knots defects in the lower leg due to the sliding osteo mie to Ilizarov. Surgeon 59, p. 357, 1988; Umyarov. G.A .: Repositioning-elongation for infected post-traumatic leg defects. In: Advances Orthop. Surgery. Williams & Willi ams, Baltimore, P 58-62, 1985). The fixator external under  differs from the internal osteosynthesis processes, in relation to the fragment movements at the fracture gap insignificant (R. Hoffmann, J. McKellop, A. Sarmiento, B. Lu. Lecture: Three-dimensional measurement of fragments movements at the fracture gap, 54th annual meeting of the German en Society for Trauma Medicine, Berlin, 1990, Cun ningham JI. M. Evans, J. Kenwright, Measurement of Frac ture movement in patients treated with unilateral exter nal skeletal fixation, J-Biomed-Eng., P 118-122, II (2), 1989).

The principle of modern osteosynthesis is based on Pauwels' investigations of the causal histogenesis of the connective tissue. (F. Pauwels .: Collected treatises on the functional anatomy of the musculoskeletal system. Springer, Berlin 1965, F. Pauwels .: Atlas on the biomechanics of healthy and diseased hips. Springer, Berlin, 1973). Bone tissue forms under mechanical stress (compressive or tensile stress) with absolute rest at the same time. The principles of modern osteosynthesis are based on these examinations (ME Müller, M. Allgöwer, R. Schneider, H. Willen egger, Manual der Osteosynthese, 2nd edition, Springer, Berlin, Heidelberg, New York, 1977). When fractures are stabilized internally, pressure is always applied to the fracture gap. The interfragmentary pressure is in long Röhrenkno chen with plate osteosynthesis z. B. in the tibia between 800-1400 N. This corresponds to a pressure of un dangerous 2-3.5 N / mm ² . These values are approximately one-third to one-fiftieth of the maximum compressive strength of compact bones (H. Yamada, Strength of biological materials. Williams & Williams, Baltimore 1970). In practice, these pressure forces are not achieved externally with the fixator. So far, the patient has been subjected to an axially dynamic fixator externally with a part of his body weight.

Criticism of the state of the technique

The comprehensive theoretical foundations, including  of broad practical experience, so far found at Therapy with the external fixator is insufficient turn. Tensile or compressive forces are either over Threaded rods, over pull wires or just over the part loading by the patient with axially dynamized External fixator on the interfragmentary area practices. In fracture treatment with the external fixator one tries to compress the fracture gap, ap but not the pressure forces such. B. at the Plate osteosynthesis.

Furthermore, since the increase in interfragmentary pressure depends on the patient's weight load, cannot have constant interfragmentary compressive forces being constructed. Inattention or slipping with sudden full load ultimately irritate the ge wanted bone healing process.

The internal osteosynthesis requires completion the bone healing of a new operation for ent Removal of the implant, usually with anesthesia and inpatient connected to hospitalization.

task

The invention has for its object the advantages the interfragmental force application of the internal os Transfer teosynthesis to external fixation. It an external fixator is to be found that has a con constant and controlled tensile or compressive force, independent ig from the cooperation of the patient on the interfragmen exercised in the primary area. The tensile or compressive force should be quan be quantifiable and measurable. To switch off the legs Flowability through the patient is said to B. the weight load on the affected limb has no influence that have interfragmental power. Furthermore, by the new fixator external the treatment time, the statio hospital stay and unable to work be shortened. An implant removal should be without Anesthesia can be done on an outpatient basis. A weight load Treatment should be possible immediately without plaster treatment.

solution

Fig. 1 shows the external axial fixator-dynamized invention. In the figure, 1 means the spring element, 2 the damping element in the axially dynamic fixator externally and 3 the force measuring probe in the spring element.

This object is achieved by inserting quantifiable, changeable spring elements ( 1 ) into the interfragmentary area of an axially dynamized fixator externally, so that compressive or tensile forces can act on the fracture area. It does not matter how the pressure or tensile force is built up. Be it about solid, gaseous or liquid matter. In order to switch off the load pressure due to body weight, the spring elements are combined with damping elements ( 2 ). So the patient can e.g. B. externally load the leg immediately after the fixator is applied, without this compressive force acting on the interfragmentary area. Pressure or tensile force measuring probes in the spring elements ( 3 ) quantify the force and thus allow the spring elements to be corrected.

Achievable advantages

The axially dynamized fixator ex ters with spring elements, with or without a combination of Damping elements enables a controlled, quan tifiable and correctable tensile or compressive force tapes application to the interfragmentary area. Across from the internal fixation gives the advantage of strength control, force correction with complete independence of the cooperation of the patient and associated with it The advantages of the fixator: Lighter technical and operational Implantation, no plaster immobilization, fewer complications ward, shorter hospital stay, immediate burden availability of the affected limb and the loss  the stationary implant removal with a new one Anesthesia is a shorter incapacity to work, overall lower cost. The external fixator can be reused be applied. By completely eliminating the plaster treatment, in contrast to the internal osteosynthesis less waste is also produced.

Claims (6)

1. External fixator with axial dynamization, characterized in that quantifiable tensile or compressive forces are exerted on the interfragmentary area by spring elements. 2. External fixator with axial dynamization according to An saying 1, characterized in that the spring elements te with or not combined with a damping element be kidneyed to z. B. the weight of the patient neutralize on the interfragmental area. 3. External fixator with axial dynamization according to An saying 1 and 2, characterized in that the by the spring elements exerted tensile or compressive forces are variable and / or quantifiable. 4. External fixator with axial dynamization according to An saying 1, 2 and 3, characterized in that axially to the spring elements and / or damping elements Pressure measuring probes can be introduced, which the Measure inter-fragmentary tensile or compressive forces. 5. External fixator with axial dynamization according to An saying 1, 2, 3 and 4, characterized in that the axially inserted spring elements and damping elements elements about solid, liquid or gaseous matter train or apply pressure. 6. External fixator with axial dynamization according to An saying 1, 2, 3, 4 and 5, characterized in that the axially inserted spring and damping elements in principle to any kind of screws, pins or sewing gels can be attached.