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A new technique is presented for the treatment of comminuted intraarticular fractures of the base of the thumb metacarpal. A triangular Hoffmann external radius and first- and second-metacarpal fixator is used. The reduction is maintained by prolonged distraction and abduction of the first metacarpal bone. The application of the technique in three cases is reported.
Tibia osteotomies in sheep were stabilized in nail-fixed and wire-fixed external devices with static longitudinal compression. During the 8-week study programme the mechanical situation of the osteotomies was checked via continuous measurements of interfragmentary tension, used as a functional indicator of stabilization. Simultaneously the test animals were marked by polychromatic fluorescent pigments. The histological findings made at the site of osteotomies showed that the temporal and local progress of ossification was influenced by the degree of stability of osteosynthesis. Under stable osteosynthesis conditions primary bone healing occurred analogous to findings in flattened experimental shaft fractures. On grounds of varying stability performance of external pressure osteosynthesis differences in secondary healing of osteotomies were observed due to interfragmentary instability.
Calcaneus traction is a common temporary procedure in fractures of the lower leg, when an internal fixation is not permitted for soft tissue reasons. Usually a Steinmann-pin or a K-wire is driven across the calcaneus, which is a simple manoeuvre performed in local anaesthesia. Infection due to this perforation of the calcaneus are rare, but signify for the patient a catastrophic complication. With the introduction of the pinless external fixateur in 1991 in clinical trials a very handy pinless-clamp exists, which can safely be anchored in the heel and thus permits safe calcaneus traction without any transosseous fixation. We have used this pinless clamp in 39 patients for various reasons and haven't stated any major complications. The clamp has proved to be very useful for temporary traction as well as for the fixation of the leg during closed intramedullary nailing using the fracture table.
PURPOSE: To assess the restoration of the bone mass of the distal radius following the use of implants in the distal radial fragment. Highly comminuted Frykman type 7 and 8 fractures were studied to determine whether the use of fixation pins in the comminuted distal radial fragment leads to osteopenia in the distal radial fragment after healing of the fracture. METHODS: As part of a clinical trial, 30 patients with comminuted intra-articular fractures of the distal radius were treated with closed reduction, external non-bridging fixation, and early postoperative mobilisation. To detect local osteopenia, bone density measurements were taken at the distal metaphysis and mid-diaphysis following healing of the fractured radius and the contralateral unaffected radius in 12 patients. RESULT: The mean age of the 12 patients for whom bone density measurements were recorded was 52.5 years (range, 39-87 years). There were 9 females and 3 males included in the study. Seven patients had a Frykman type 8 fracture and 5 patients had a Frykman type 7 fracture. Significant osteopenia was absent despite the use of four 2.5-mm fixation pins in the distal fragments of the healed distal radial fracture. The median value of the maximal step was 2.8 mm (range, 0-9.1 mm). The median value of the intra-articular interfragmentary gap was 1.8 mm (range, 0-13.4mm). CONCLUSION: The findings of this study do not suggest long-term osteopenia following the use of four 2.5-mm pins in the distal fragments. The non-bridging fixator, by allowing early physical activity, possibly led to satisfactory functional and structural results.
Today, reconstructive surgery knows many different skin flaps for treating soft tissue defects. The advantages of Hoffmann's external anchorage are demonstrated by immobilizing skin flaps during their process of healing.
A young female camel had a complete comminuted midshaft fracture of the right radius. The fracture was repaired by external coaptation, which involved 2 full-limb fiberglass casts for 15 weeks. A Thomas splint was placed around the second cast for 12 weeks. The fracture healed in nonaligned configuration, and although lameness was substantial after the fracture had healed, the camel's breeding potential had been salvaged. This successful outcome is an indication that a high-limb fracture in a camel bone (in this case a radius) may be managed by external coaptation and repair by callus formation.
Biomechanical experiments have shown high stability and load acceptance of the pelvis if the external device is mounted as a trapezoid compression frame. Clinical results in 22 patients with double vertical pelvic fractures illustrate the reduction of displaced pelvic fractures and the mounting of the frame. Reduction is obtained under general anesthesia within two days of the trauma. The external compression frame affords noteworthy relief of pain in all patients and greatly facilitates nursing. The patients were verticalized three weeks later and the frame removed six weeks after its applcation. There was one death. The early stabilization of the pelvis and consequently controlled hemorrhage may have contributed to the low mortality. At follow-up, the radiographic result was graded as excellent in 15 cases, good in four cases and poor in two cases. Impaired gait was recorded in two patients and persistent low back pain in one. The trapezoid compression frame is applied as soon as possible after admission of all patients with severely unstable pelvic fractures.
The mechanical principle of function of the Harrington instruments or of the spinal stabilization by means of plates does not meet the anatomical and mechanical conditions in instable fractures of the thoracic and lumbar spine sufficiently. The requested qualities in regard to fixation of the material, shortness of fusion distance, possibility of reduction and variability according to individual situations can be met only by the fixateur externe. Magerl was able to verify the correctness of this thesis by means of the fixateur externe constructed by himself. It was logic for us to practice the mechanical principle of the fixateur externe in using the implantation instruments which were positioned directly to the spine. The first instruments of this kind were introduced by Dick in 1983 and were used in Bad Wildungen since November 1983 successfully. The practical experiences of more than 40 operations using the Dick fixateur interne resulted in the development of own instruments applied by us since the beginning of 1985 as preliminary prototypes.
Purulent osteomyelitis in the foot region, accompanied by peripheral polyneuropathy, represents a grave complication after initially insufficient treatment of soft-tissue infections. The possible use and advantages of the external minifixator as an alternative to immediate primary forefoot or foot amputation are described. Initial results of personal observations are described.
A testing machine to study fracture gap motion ex vivo was devised. The apparatus permits direct measurement of bending and shear at a fracture site under different loading conditions. Using this device the single and double frame Hoffmann external fixateurs were compared to a Küntscher medullary nail. Shear displacements of (0.4-1.7 mm) were observed for the fixateurs as opposed to 0.3 mm for the intermedullary nail. Changing from a single to a double frame halved hinge motion at the fracture site and reduced shear by 25%.
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A new technique for arthrodesis of the PIP joint is described; after resection of the joint two percutaneous Kirschner wires of diameter 1.2-1.3 mm are placed transversely through the two phalanges. The wires are twisted together on each side of the finger to produce a compression effect on the bone surface. Additional external immobilisation is used for five days only, but the wires are left in place for six weeks. The method has been used without complication in ten patients. The average length of time off work was seven and a half weeks. In the author's view the advantages of this method lie in its technical simplicity and in the free movement of other finger joints.
Using a ball-and-socket joint model, the optimal mechanical design of a simple universal ball joint was established. The maximum resistive moment was 70-72 Nm for a tightening torque moment of 5 Nm, their ratio being 14. The corresponding ratios for the Hoffmann universal ball joint and Orthofix are 1.0-4.3 and 1.1-1.6, respectively. A complete unilateral frame consists of two ball joints and one square connecting tube. Full-frame behavior under external loads was tested in the three principal planes and in torsion. Compared with a Hoffman quadrilateral system, the new system was four times more rigid in the anteroposterior plane, similar in axial load and lateral bending, and 64 percent more rigid in torsion.
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The intent of this study was to investigate the stress distribution in cortical bone around fracture fixation pins and around pins coated with various polymeric and elastomeric materials. Since these interface stresses cannot be measured directly, a photoelastic technique was employed and stresses were measured in two-dimensional bone models fabricated from sheets of epoxy resin. Our results showed that when a fixation pin was loaded in compression, the compressive stress measured in the model was greatest at the pin-model interface. The magnitude of the compressive stress was found to diminish steeply away from the hole in a log decrement distribution which was asymptotic to the value of the average stress in the model. When polymeric and elastomeric materials were applied as pin coatings and the performance of the coated pins was compared to that of uncoated pins of the same overall diameter, a reduction of the maximum stress in the bone model was demonstrated. Among the coatings tested, we found that of the polymeric materials ultrahigh molecular weight polyethylene (UHMWPE) was most effective at reducing the peak cortical stress magnitude. The most effective coating material overall was found to be silicon elastomer. Computation of stress values in models loaded through stainless-steel pins and through pins coated with 1-mm silicon elastomer showed that the presence of the elastomer layer caused a reduction of about 50% in the maximum compressive stress in the model.
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Explore the source record for details and available documents.