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At least 253 records · Page 14Linked to original sources
PubMed2002

Fixation stability of comminuted humeral shaft fractures: locked intramedullary nailing versus plate fixation.

BACKGROUND: This study compared the fixation stability of two treatments for humeral shaft fractures with segmental bone loss during cyclic, physiologic loading. METHODS: Six matched pairs of human humeri received either a 10-hole broad dynamic compression plate or a locked antegrade inserted humeral nail applied to a humeral diaphyseal osteotomy with a 1.5-cm gap defect. The bone-implant humeral constructs were axially loaded for 10,000 cycles at 250 N and 500 N, with measurements of gap displacement and calculation of construct stiffness. The specimens were then loaded to failure. RESULTS: Cyclic loading showed no difference between the two groups for average gap displacement or construct stiffness. The intramedullary nail constructs failed by humeral shaft splitting (n = 4) or head cut-out (n = 2) at an average of 958.3 N, whereas the plate constructs failed by humeral shaft splitting and screw pull-out (n = 3) or plate bending (n = 3) at an average of 641.7 N (p < 0.001). CONCLUSION: Although both methods offer similar fixation stability under physiologic loads, the higher load to failure demonstrated by intramedullary nail fixation may have implications for the patient with multiple injuries for whom partial weightbearing on the injured upper extremity may be necessary.

Adult↗
PubMedDate not supplied

Effects of static fixation and dynamization after interlocking femoral nailing locked with an external fixator: an experimental study in dogs.

OBJECTIVE: To determine bone healing at 20 weeks, after either static fixation (SG) or after dynamization (DG) at 4 weeks in osteotomized canine femurs repaired with an interlocking nail (ILN) secured with a type I external skeletal fixator (ESF). STUDY DESIGN: Experimental study. ANIMALS: Ten adult beagle dogs. METHODS: After mid-diaphyseal femoral osteotomy, femurs in 10 dogs were repaired with an ILN secured with 4 (2 proximal, 2 distal) threaded custom pins (TP; 2.7-mm-diameter cortical screw with a 2-mm shaft attached to the screw head) to which 2 parallel connecting bars were attached in a type I ESF configuration. In 5 dogs, dynamization was performed at 4 weeks by removing the connecting bars and 2 distal screws. Limb function, range of motion of the stifle joint (ROMSJ), radiographic evidence of bone healing, and complications were studied for 20 weeks. RESULTS: Full limb function was achieved between 8 and 10 weeks in SG dogs, but a decreased ROMSJ was observed from 5 to 8 weeks. In DG dogs, full limb function occurred between 5 and 6 weeks except in 1 dog, and ROMSJ was considered normal in all dogs. Bone healing was not affected by dynamization. Average healing time for SG was 12.8 weeks, and for DG it was 13.6 weeks. Periosteal reaction at TP insertion points, osteolysis around the thread and head of TPs were observed in both groups. A windshield-wiper effect was observed at the tip of 1 ILN. CONCLUSION: ILN locked with a type I ESF can be used for fixation of mid-shaft femoral fractures. Dynamization at 4 weeks did not affect bone healing but did prevent stifle ankylosis and promoted earlier limb function. CLINICAL RELEVANCE: ILN locked with a type I ESF is seemingly a feasible method for repair of mid-shaft femoral fractures and may decrease risk of nail failure.

Animals↗
PubMed1994

Removal of internal fixation--the effect on patients' complaints: a study of 66 cases of removal of internal fixation after malleolar fractures.

To estimate the effect of removal of internal fixation after treatment of malleolar fractures on postoperatively presented complaints, we retrospectively evaluated 66 patients by their records and by personal questionnaires. Of all the patients, 89.4% had one or more complaints. These were typically soreness over implant and cicatrix, reduced movement of the ankle joint, and strain-related pain. About 75% of these patients reported improvement after removal. The AO mode of fixation, i.e., typically by lateral semitubular plating and transsyndesmotic screw and a medial screw or pins, and the Wiberg-Cedell mode, i.e., typically consisting of lateral single or double cerclage and staple and medial pinning, constituted the principal groupings of the patients. The two groups were comparable. In this series, we found significantly more complaints associated with the AO mode in the postoperative period. We conclude that removal of internal fixation after malleolar fractures is indicated when common types of complaints are presented.

Adolescent↗
PubMed1992

[Experimental study of external fixation of femoral fractures. Mechanical properties of different kinds of fixation. Clinical implications].

An in vitro assessment of the mechanical performance of 10 types of external femoral stabilization allowed the amplitudes of fracture site displacements during the initial loading phase of a comminuted fracture treated by external fixation to be established. The largest displacement to load ratios were observed in the sagittal plane for all tested configurations. The highest fixator stiffnesses were obtained by using large diameter tubes and pins. The most rigid fixators have a derigidification system which creates the problem of choosing the ideal time to change the rigidity.

External Fixators↗
PubMed1976

[Comparison of the sensitivity of complement-fixation test and latex-fixation test in the demonstration of a migration phase of ascariasis (Ascaris suum) in a non-specific host].

The authors compared the sensitiveness of the complement-fixation reaction and the latex-fixation test in the demonstration of a migration phase of ascariasis in a non-specific host (rabbit). The sensitiveness of the latex-fixation test was higher by the value of one dilution of the geometric series, on an average.

Animals↗
PubMed1993

[The LS-8 lever fixator: repositioning and fixation aids for dislocations and dislocation fractures of the lumbar spine and the thoracolumbar transition. Part I. Biomechanical considerations and surgical technique].

We are reporting a lever-type internal fixateur, the LS-8 system, which can be used for reduction and stable fixation of fractures and fracture-dislocations of the thoraco-lumbar and lumbar spine. The LS-8 system is different from all previous systems: it combines the advantages of the spinal fixateur interne and conventional plate fixation, while largely avoiding their disadvantages, such as the fixed position of the screw hole and the mechanical overloading of the fixing points, as in the previous hook-type systems. In order to minimize these drawbacks, we have added a plate of variable length to our system, creating a fulcrum that prevents overloading. This means that the reinforced 8 mm diameter screws function as lever arms around this fulcrum, conducting and counterbalancing the active forces. As a result, the loading capacity of our system has been greatly improved. Since the LS-8 "lever fixateur" is a reinforced system, it is no longer necessary to use any plaster or brace fixation. We should like to illustrate the advantages and the capability of the LS-8 system by presenting one of our cases.

Biomechanical Phenomena↗
PubMed1997

External fixation of children's fractures: use of the Orthofix Dynamic Axial Fixator.

We have reviewed 48 children's diaphyseal fractures of the femur and tibia managed with the Orthofix Dynamic Axial Fixator between 1987 and 1994. The indications for external fixation included open fractures, multiple injuries, failed conservative management, and unstable fracture configurations. All fractures healed without further surgical intervention, and the incidence of serious complications was low. Although pin track sepsis was common, compromise of the fixation as a result of this occurred in only one case. We conclude that use of the Orthofix for children's fractures is a safe and effective management option.

Adolescent↗
PubMed1993

Variable fixation of staphylococcal slime by different histochemical fixatives.

A variety of histochemical fixatives were used to compare the fixation of bacterial films produced by a standard slime-producing strain of Staphylococcus epidermidis on plastic tissue culture plates. Some reagents were completely ineffective in fixing the slime layer, whereas others gave variable results. The best alternative to the fixative of the reference method, the potentially explosive Bouin's reagent, was air drying.

Bacteriological Techniques↗
PubMed2001

[Angle- and rotation-stable internal fixation of proximal humerus fractures with the humerus fixator plate. Early clinical experience with a newly developed implant].

INTRODUCTION: The Humerus Fixator Plate is presented as a new implant for angle- and rotation-stable internal fixation for the operative treatment of proximal humerus fractures at the surgical neck. METHODS: In an ongoing two-centre study, 47 patients were treated with the new implant. To date, 31 patients had clinical and radiological postoperative follow-up examinations with a mean interval of 10 months (range: 6-14 months). RESULTS: In 46 patients (97.9%), complete angle and rotational stability was achieved without limiting the range of motion or requiring immobilization. Good pain relief was obtained in 43 patients (91.5 %), and 3 patients (6.4%) showed moderate pain relief following surgery. There was one implant failure. Utilizing the Constant-Raw score (without any correction factors), a mean result of 82.8 points (range: 46-100 points) was ascertained. The majority of the patients (87.1%) achieved "excellent" or "good" clinical results. X-ray analysis revealed no non-union nor humerus head necrosis. In 4 cases (12.9%), protrusion of a humerus head screw was observed which mandated removal of the implant. CONCLUSION: The first clinical investigations of the novel Humerus Fixator Plate are encouraging and provide essential advances in the treatment of unstable proximal humerus fractures.

Adult↗
PubMed2000

External fixation of distal radial fractures: 3 or 5 weeks of external fixation.

In a retrospective study we compare the functional and radiographical results of 2 groups of patients with unstable distal radial fractures treated with external fixation. In Group 1, 20 patients with 21 fractures were treated with external fixation for 3 weeks followed by a cast for 2 weeks. In Group 2, 16 patients were treated with external fixation for 5 weeks. The functional outcome was good in both treatment groups with no significant difference between the results in the two groups. Radiologically, Group I had less radial shortening than Group II, but there was no difference in the degree of dorsal angulation.

Aged↗
PubMed2005

Evaluation of bone plug and soft tissue anterior cruciate ligament graft fixation over time using transverse femoral fixation in a sheep model.

PURPOSE: To evaluate the mechanical role of bone-anterior cruciate ligament (ACL) graft junction in comparison with primary fixation of the graft. TYPE OF STUDY: Ex vivo controlled biomechanical study. METHODS: An ACL reconstruction was performed on 2 groups of 40 sheep each. The ACL graft was patellar tendon in group 1, and free tendon in group 2. Load-to-failure tests were performed at 1, 2, 3, and 6 months. Each group was divided into 2 subgroups: In subgroup A the femoral fixation devices were removed before testing and in subgroup B they were left in place. RESULTS: At 1 month, structural properties of subgroup 2A were significantly lower than other subgroups. Until the third month, structural properties of each subgroup were significantly lower than normal ACL. Grafts always failed at midsubstance, except for subgroup 2A at 1 month, which pulled out of the femoral tunnel. CONCLUSIONS: Bone plug incorporation was stronger than graft strength at 1 month whereas soft tissue tendon incorporation was not stronger than graft until 2 months. At 3 months, both groups failed at approximately 30% of the native ACL strength, and at 6 months, both groups were nearly equal in terms of load to failure and stiffness. CLINICAL RELEVANCE: High fixation strength and stiffness of ACL graft does not allow earlier return to sports activities.

Animals↗
PubMed2005

Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation.

We assessed syndesmotic set screw strength and fixation capacity during cyclical testing in a cadaver model simulating protected weight bearing. Sixteen fresh frozen legs with artificial syndesmotic injuries and a syndesmotic set screw made of stainless steel or titanium, inserted through three or four cortices, were axially loaded with 800 N for 225,000 cycles in a materials testing machine. The 225,000 cycles equals the number of paces taken by a person walking in a below knee plaster during 9 weeks. Syndesmotic fixation failure was defined as: bone fracture, screw fatigue failure, screw pullout, and/or excessive syndesmotic widening. None of the 14 out of 16 successfully tested legs or screws failed. No difference was found in fixation of the syndesmosis when stainless steel screws were compared to titanium screws through three or four cortices. Mean lateral displacement found after testing was 1.05 mm (S.D. = 0.42). This increase in tibiofibular width exceeds values described in literature for the intact syndesmosis loaded with body weight. Based on this laboratory study it is concluded that the syndesmotic set screw cannot prevent excessive syndesmotic widening when loaded with a load comparable with body weight. Therefore, we advise that patients with a syndesmotic set screw in situ should not bear weight.

Aged↗
PubMedDate not supplied

Further development of titanium miniplate fixation for mandibular fractures. Experience gained and questions raised from a prospective clinical pilot study with 2.0 mm fixation plates.

Miniplate systems are often used instead of more rigid systems for the treatment of mandibular fractures. While the most stable fixation method for all mandibular fractures is the 2.7 mm plate, most fracture sites and types are eminently suitable for miniplate fixation via an intraoral approach. However, the relatively low stability of the miniplate systems compared with rigid plate systems limits the indications for their use in mandibular fracture treatment, especially when immediate postoperative function is desired. A more rigid miniplate which provides increased stability was studied. The results of a preliminary study and a clinical trial of a 2.0 mm titanium miniplate system are presented in this paper. The therapeutic consequences of the lesser stability afforded by small plate systems are discussed. Indications for miniplate fixation without additional immobilization are reviewed.

Adolescent↗
PubMed1999

Single lag screw fixation for malar fracture (type B) fixation: reduction of hardware treatment costs.

In an attempt to define the most simple and inexpensive method of achieving postreduction stability in zygomatic fractures, the authors compared two different methods of internal rigid fixation of the frontozygomatic suture line in one group with miniplates and in another group with Panfix lag screws. The randomized study protocol consisted of a control group of 20 patients and 40 patients with laterally displaced body fractures of the zygoma. Statistical differences were not seen between the control subjects and the patients who required open reduction and internal fixation either with one osteosynthesis plate at the frontozygomatic suture line or a lag screw osteosynthesis. Lag screw fixation in malar type B fractures could lower hardware treatment costs and is an alternative method that provides sufficient stability in indicated patients.

Bone Plates↗
PubMed1997

Internal fixation of experimental intraarticular calcaneal fractures: a biomechanical analysis of two fixation methods.

OBJECTIVE: To evaluate and compare the mechanical stability of two different fixation techniques on experimentally induced calcaneus fractures. METHODS: Thirteen fresh frozen cadaver lower limbs had intraarticular calcaneal fractures produced with an impact loading device. Internal fixation was then performed through lateral and medial approaches using 3.5-mm interfragmentary screws fixed to the posterior facet. Next, either a five-hole 1/3 tubular or five-hole reconstruction plate was placed on the lateral cortex. Radiographs were obtained to confirm reduction. The foot was then cyclically loaded for 500 cycles with a compressive load of 98 N, followed by loading to failure. RESULTS: The displacement at the posterior facet fracture line between the loaded and unloaded foot at the 500th cycle was 0.30 +/- 0.08 mm and 0.39 +/- 0.18 mm for the tubular and reconstruction plates, respectively. These displacements were not statistically significant (Student's t test p > 0.3). The load and displacement at failure for the tubular plate were 2021 +/- 1050 N and 6.10 +/- 1.75 mm, respectively. Those for the reconstruction plate were 1923 +/- 697 N and 4.57 +/- 1.32 mm (p > 0.09). CONCLUSION: This study supports the mechanical viability of using less prominent plates for the fixation of intra-articular calcaneal fractures.

Aged↗
PubMed1996

The BWM spinal fixator system. A preliminary report of a 2-year prospective, international multicenter study in a range of indications requiring surgical intervention for bone grafting and pedicle screw fixation.

STUDY DESIGN: A prospective, international, multicenter study of 400 patients who received the BWM fixator system. OBJECTIVES: To assess the effectiveness and safety of the system in the management of various conditions requiring spinal fixation and bone grafting. SUMMARY OF BACKGROUND DATA: The BWM system was developed for the management of spinal instability of all etiologies occurring in the thoracic, thoracolumbar, and lumbosacral spine. METHODS: Patients with fracture, tumor, spondylolisthesis, spondylitis, failed back, or other degenerative conditions of the spine received the BWM instrumentation as described in the study literature and were regularly reviewed for 2 years. RESULTS: The results from the first 200 patients to complete the study showed an overall graft fusion rate of 94% (95% confidence interval: 91.3%-97.6%). There were marked improvements in measures of functional ability (P < 0.001, Wilcoxon test). Before surgery, less than half the patients were capable of outdoor activity. At 2 years, 80% were able to undertake outdoor activity. There were few perioperative difficulties reported. Postoperative complications associated with major surgery were seen in 18% patients. There were 23 (2.6%) pedicle screw failures, including two loosenings, and 13 (2.5%) spacer element failures, including three loosenings. CONCLUSIONS: Clinical failure was not necessarily a consequence of component failure. The BWM fixator provided excellent stabilization during the process of bone graft consolidation. The risks of complication or component failure were no higher than those associated with similar devices.

Adult↗
PubMed1984

Complement fixation by pemphigus antibody. I. In vitro fixation to organ and tissue culture skin.

Although complement is often detected in the intercellular substance of pemphigus skin lesions, the ability of pemphigus antibodies to fix complement in vitro is controversial. The purpose of this study was to test in vitro complement fixation abilities of pemphigus antibodies further using organ and tissue culture methods. Epidermal cell monolayers from mouse tail were incubated with the purified IgG fraction of pemphigus serum followed by purified Clq. Binding of Clq, as well as IgG was demonstrated by immunofluorescence methods. When purified Clq was replaced with normal human serum as a complement source, positive C3 and C4 staining were also evident. When purified IgG of normal human serum was used in place of pemphigus IgG, similar immunofluorescence staining was not observed. Further evidence for complement fixation in vitro by pemphigus antibodies was obtained using organ cultures. Organ culture of normal human skin and monkey esophageal mucosa cultured in purified pemphigus IgG showed intercellular substance binding of IgG. No binding was observed when normal IgG was substituted for pemphigus IgG. Additional organ culture sections were then treated with complement (fresh normal human serum) and tested by in vitro complement staining. Fixation of Clq, C4, and C3 was noted in intercellular substance areas of organ cultured skin and mucosa incubated with pemphigus IgG but not those incubated with normal IgG. Prior treatment of pemphigus IgG organ cultured skin sections with unlabeled anti-C3, blocked positive C3 staining. These results suggest that some pemphigus antibodies are capable of activating complement in vitro.

Animals↗
PubMed1993

Spinal fixation. Part 1. Principles, basic hardware, and fixation techniques for the cervical spine.

Spinal fixation devices provide stability and restore anatomic alignment in the treatment of fractures, degenerative disease, infection, and tumors and correct congenital deformities such as those seen in scoliosis. The devices provide immediate stability but are not strong enough to withstand prolonged stress and eventually fail, in most cases, if bone fusion does not occur. Bone graft material is often used to promote fusion and to replace bone after resection. Internal fixation is used to maintain position and alignment and to prevent motion as the spine fuses. Plates and rods are attached to the vertebral body or posterior elements with wire, screws, and hooks. Screws and wire can also be used alone as a means of fixation. Surgical techniques and instrumentation have advanced in recent years, and radiologists are exposed to a myriad of devices. They need to be able to identify the various plates, screws, wiring techniques, and grafts used most commonly and to understand their function in the cervical spine for fusions and treatment of fractures and degenerative disease.

Cervical Vertebrae↗