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PubMed2006

Measurements of objective and subjective fixation disparity with and without a central fusion stimulus.

BACKGROUND: Fixation disparity is the condition in which the images of a binocularly fixated object are not imaged on exactly corresponding retinal points, but are still within Panum's fusional areas. Measurements of objective and subjective fixation disparity have indicated that subjective fixation disparity does not indicate the true eye position. However, the effect of the foveal fusional lock (FFL) on the relationship between objective and subjective fixation disparity is still not clear. MATERIAL/METHODS: This relationship was investigated in five subjects. The objective measurements were made using scleral search coils, and at the same time the Sheedy distance disparometer indicated the subjective fixation disparity. Measurements were obtained both with and without an FFL. RESULTS: It was found that without an FFL there was a significant difference (p<0.05) between subjective and objective fixation disparity, whereas when an FFL was added, the difference was no longer significant. Additionally, the absolute sizes of both SFD and OFD were found to be significantly smaller with the FFL. CONCLUSIONS: These results indicate that the presence of an FFL makes subjective fixation disparity a more accurate indicator of the objective eye position. An instrument with an FFL should therefore be used clinically. The difference between objective and subjective fixation disparity presumably indicates a change in correspondence.

Adult↗
PubMed2006

CYR61 (CCN1) protein expression during fracture healing in an ovine tibial model and its relation to the mechanical fixation stability.

The formation of new blood vessels is a prerequisite for bone healing. CYR61 (CCN1), an extracellular matrix-associated signaling protein, is a potent stimulator of angiogenesis and mesenchymal stem cell expansion and differentiation. A recent study showed that CYR61 is expressed during fracture healing and suggested that CYR61 plays a significant role in cartilage and bone formation. The hypothesis of the present study was that decreased fixation stability, which leads to a delay in healing, would lead to reduced CYR61 protein expression in fracture callus. The aim of the study was to quantitatively analyze CYR61 protein expression, vascularization, and tissue differentiation in the osteotomy gap and relate to the mechanical fixation stability during the course of healing. A mid-shaft osteotomy of the tibia was performed in two groups of sheep and stabilized with either a rigid or semirigid external fixator, each allowing different amounts of interfragmentary movement. The sheep were sacrificed at 2, 3, 6, and 9 weeks postoperatively. The tibiae were tested biomechanically and histological sections from the callus were analyzed immunohistochemically with regard to CYR61 protein expression and vascularization. Expression of CYR61 protein was upregulated at the early phase of fracture healing (2 weeks), decreasing over the healing time. Decreased fixation stability was associated with a reduced upregulation of the CYR61 protein expression and a reduced vascularization at 2 weeks leading to a slower healing. The maximum cartilage callus fraction in both groups was reached at 3 weeks. However, the semirigid fixator group showed a significantly lower CYR61 immunoreactivity in cartilage than the rigid fixator group at this time point. The fraction of cartilage in the semirigid fixator group was not replaced by bone as quickly as in the rigid fixator group leading to an inferior histological and mechanical callus quality at 6 weeks and therefore to a slower healing. The results supply further evidence that CYR61 may serve as an important regulator of bone healing.

Animals↗
PubMed1992

Mechanical properties of the Pinless external fixator on human tibiae.

UNLABELLED: In the treatment of either acute severe open tibial fractures or their sequelae, a convenient external fixator is desirable. The conventional transosseous fixation with pins entering the medullary cavity is associated with problems such as pin loosening and pin track infection. Due to the bacterial contamination of the medullary space via the pin track the change of treatment from primary external fixation to secondary medullary nailing is an infection risk. In order to minimize these problems an external clamp fixator, the Pinless, was created. Medullary penetration is avoided by substitution of the conventional pins with clamps. The latter are inserted by hand (removable handles) and anchored only in the bone cortex. The medullary cavity stays intact. But is this clamp fixation stable enough for clinical use? MATERIAL AND METHODS: On paired human cadaver tibiae, we compared the mechanical properties of the experimental Pinless, the conventional AO-tubular fixator and the Ultra-X fixator. Clamps differing in size (small/large) and material (steel/titanium) were used and compared to Schanz screws (steel, 5.0 mm diameter). We measured the stiffness of comparable configurations (1 or 2 bars) under axial compression, four-point-bending in two planes, and torsion. The pull-out force of the different clamps in relation to the bone diameter and number of rocking movements during insertion was also determined. RESULTS: The Pinless configurations with small clamps and 1 bar showed stiffness values as follows (as a percentage of the corresponding AO-tubular fixator): 42/36% (steel/titanium clamp) axial stiffness, 61/43% bending stiffness perpendicular to the reference plane, 78/79% bending stiffness parallel to the reference plane, and 90/95% torsional stiffness. The corresponding Ultra-X device was not as stiff as the Pinless. The use of two longitudinal rods increased the relative stiffness only under axial compression. The mean pull-out force on the proximal tibia was 1011 N for the small steel clamp, 717 N for the large steel clamp, 681 N for the small and 777 N for the large titanium clamp. At the lowest tibial diameter the values were reduced by 10 to 43%. The rocking movements doubled the pull-out force, e.g. there was a pull-out force for the large clamp of 600 N with five rocking movements compared to 310 N without. DISCUSSION: The Pinless was not as stiff as the conventional AO-tubular device but stiffer than the clinically used Ultra-X, especially in sagittal bending, the main load on a tibial fracture in the first weeks after trauma.(ABSTRACT TRUNCATED AT 400 WORDS)

Biomechanical Phenomena↗
PubMed2004

The role of external fixation in acute ankle trauma.

The use of external fixation methods has become increasingly popular throughout the past decade in the treatment of tibial pilon fractures to prevent the dreaded soft tissue complications after high velocity injuries. A variety of methods has been proposed, including ankle-spanning half-pin frames; circular (Ilizarov) frames with tensioned wires; or hybrid frames, either as the sole treatment or, more frequently, in conjunction with limited internal screw fixation. External fixation also has a role in staged protocols as a primary tool for reduction and preliminary fixation until soft tissue consolidation makes internal fixation feasible. Although good to excellent results are reported in a high percentage of cases in most studies and infection rates have dropped to less than 10%, even for high velocity injuries with considerable soft tissue compromise, no single form of treatment seems to be suitable for all types of pilon fractures. Major concerns after external fixation are the development of pin track infections, malunions or nonunions, and the danger of imperfect reduction of the articular surface. Staged protocols that are based on the severity of the fracture and soft tissue injury are likely to play a major role in the future treatment of pilon fractures. In the treatment of acute malleolar fractures, ankle-spanning external fixation is reserved for fractures with considerable soft tissue compromise, open fractures, or compartment syndrome as a temporary transfixation until internal fixation becomes feasible.

Acute Disease↗
PubMed2001

Hinged elbow fixation for recurrent instability following fracture dislocation.

The purpose of this study was to evaluate the use of an articulated external fixator of the elbow in the management of instability after fracture dislocation. We retrospectively reviewed results of eight patients treated with an articulated external fixator between 1998 and 1999. Study inclusion criteria included recurrent/chronic dislocation following fracture dislocation. Patients were divided into two groups based on the onset of instability. Group I (n=3) included patients with acute instability. The indication for use of the articulated external fixator in this subset of patients was the inability to accomplish complete osseous and ligamentous repair secondary to high degrees of comminution and/or severe soft tissue defects. Group II (n=5) patients presented at least 6 weeks after the original injury; the indication for use of the external fixator was inability to maintain joint congruity following open reduction. Application of the fixator was performed as an alternative to reconstruction of both medial and lateral ligaments. Follow-up at 1.5 years consisted of radiographs, occupational therapy ROM and DASH outcome measurement. At follow-up, Group I patients maintained an average total arc of motion of 120 degree, average flexion contracture: 25 degree, average pronation: 90 degree, and average supination: 67 degree. Group II patients had an average total arc of motion of 84 degree, average flexion contracture: 33 degree, average pronation: 68 degree, and average supination: 43 degree. Radiographic appearance of patients in both groups revealed a congruent humero-ulnar joint. DASH forms indicated patients experienced mild difficulty with activities of daily living. In conclusion, global instability of the elbow after fracture dislocation remains a difficult problem. High-energy injuries may result in an inability to maintain a congruous humero-ulnar articulation despite osteosynthesis and direct repair of the medial collateral ligament (MCL) and LUCL. When repair of the coronoid process and MCL is not feasible secondary to excessive comminution or soft tissue defect, the use of an articulated external fixator permits concentric stability and reduction of the humero-ulnar articulation. In cases of chronic instability, application of an articulated external fixator provides an alternative to complete osseous and ligamentous reconstruction. In both acute and chronic situations, the use of the articulated elbow fixator results in most patients regaining very good functional use of the elbow.

Adult↗
PubMedDate not supplied

Are circular external fixators weakened by the use of hemispheric washers?

OBJECTIVES: To compare the axial mechanical stability of 3 circular external fixators systems with and without hemispheric washers. STUDY DESIGN: Experimental study. METHODS: The axial stiffness and load necessary to produce 0.5 and 1 mm of displacement of 10 circular external fixator constructs from 3 manufacturers were tested on a materials testing machine. The constructs tested included the Small Bone fixator (SBF; Hofmann S.a.S., Monza, Italy), the IMEX ring fixator (IMEX Inc., Longview, TX), and the Multiplanar C-Fix (MCF; PanVet Distribuzione, Seriate, Italy). Five configurations were tested for each construct: (1) conventional nut fixation, (2) hemispheric washer fixation with connecting rods offset by 0, (3) 1, and (4) 2 holes, and (5) with a ring placed at maximum angulation. RESULTS: The loads resisted at 0.5 and 1 mm of displacement did not differ when frame configurations were compared (P =.25733 and.33769, respectively). The linear stiffness of the following configurations were decreasingly stiff: standard constructs, hemispheric washers with connecting rods perpendicular to rings, hemispheric washers with connecting rods offset by 1 hole, hemispheric washers with connecting rods offset by 2 holes, and ring offset in relation to bone model. The SBF constructs tested were 34% and 41% more rigid than the IMEX and MCF constructs tested despite the larger diameter of the connecting rods for the IMEX frames (6 mm) compared with the SBF frames (5 mm). The IMEX constructs tested were 6% more rigid than the MCF constructs tested. CONCLUSIONS: Adding hemispheric washers and angling connecting rods in relation to rings did not influence the loads resisted at 0.5 and 1 mm displacement but decreased construct stiffness. CLINICAL RELEVANCE: The use of hemispheric washers had minor effects on the biomechanical performance of fixator frames tested in this study when used to angle a ring in relation to connecting rods for circular external fixators.

Animals↗
PubMedDate not supplied

HistoChoice as an alternative to formalin fixation of undecalcified bone specimens.

We compared histochemical and immunohistochemical staining as well as fluorochrome labeling in murine bone specimens that were fixed with 10% neutral buffered formalin to those fixed with HistoChoice. We showed that sections from undecalcified tibiae fixed for 4 h in HistoChoice resulted in enhanced toluidine blue and Von Kossa histochemical staining compared to formalin fixation. HistoChoice produced comparable or improved staining for alkaline phosphatase. Acid phosphatase localization was better in formalin fixed specimens, but osteoclasts were visualized more easily in HistoChoice fixed specimens. As expected, immunohistochemical labeling was antibody dependent; some antibodies labeled better in HistoChoice fixed specimens while others were better in formalin fixed specimens. Toluidine blue, Von Kossa, and alkaline phosphatase staining of sections fixed for 12 h produced sections that were similar to 4 h fixed sections. Fixation for 12 h preserved acid phosphatase activity better. Increasing fixation to 12 h affected immunolocalization differentially. Bone sialoprotein labeling in HistoChoice fixed specimens was comparable to formalin fixed samples. On the other hand, after 12 h formalin fixation, osteocalcin labeling was comparable to HistoChoice. For most histochemical applications, fixing murine bone specimens for 4 h with HistoChoice yielded superior staining compared to formalin fixation. If immunohistochemical localization is desired, however, individual antibodies must be tested to determine which fixation process retains antigenicity better. In addition, there was no detectable difference in the intensity of fluorochrome labeling using either fixative. Finally, fixation duration did not alter the intensity of labeling.

Animals↗
PubMedDate not supplied

Determination of optimal rehydration, fixation and staining methods for histological and immunohistochemical analysis of mummified soft tissues.

During an excavation headed by the German Institute for Archaeology, Cairo, at the tombs of the nobles in Thebes-West, Upper Egypt, three types of tissues from different mummies were sampled to compare 13 well known rehydration methods for mummified tissue with three newly developed methods. Furthermore, three fixatives were tested with each of the rehydration fluids. Meniscus (fibrocartilage), skin, and a placenta were used for this study. The rehydration and fixation procedures were uniform for all methods. The stains used were standard hematoxylin and eosin, elastica van Gieson, periodic acid-Schiff, and Grocott, and five commercially obtained immunohistochemical stains including pancytokeratin, vimentin, alpha-smooth-muscle-actin, basement membrane collagen type IV, and S-100 protein. The sections were examined by transmitted light microscopy. Our study showed that preservation of the tissue is dependent on the quality and effectiveness of the combination of the rehydration and fixation solutions, and that the quality of the histological and histochemical stains is dependent on the tissue quality. In addition, preservation of the antigens in the tissues is dependent on tissue quality, and fungal permeation had no influence on the tissue. Finally, the results are tissue specific. For placenta the best solution combination was Sandison and solution III (both fixed with formaldehyde) while results for skin were best with Ruffer I (using formaldehyde and Schaffer as fixatives), Grupe et al. (using formaldehyde as a fixative) and solution III (in combination with formaldehyde and Bouin fixatives). Ruffer II (using formaldehyde as a fixative) and solution III (in combination with Schaffer fixative) gave the best results for fibrocartilage.

Cartilage↗
PubMed2000

Effect of formalin tissue fixation and processing on immunohistochemistry.

Although immunohistochemistry is routinely performed by many pathology laboratories, its standardization still lags behind. A major cause of variation in the reproducibility of immunohistochemical staining is induced by tissue fixation and, to a lesser degree, tissue processing. This report, stemming from the first meeting of the International Consensus Group on Standardization and Quality Control (ICGSQC) in Nice, France, summarizes the problem and suggests solutions to begin to achieve standardization of fixation and processing. Most laboratories use neutral-buffered formalin (10%) for tissue fixation which introduces cross-links, whereas coagulative fixatives are less popular. Problems with formalin fixation comprise delay of fixation and variations in the duration of the fixation mainly. Solutions to these problems could be to start fixation soon (<30 min) after surgical removal of the tissue and to avoid overfixation (>24-48 hrs). For tissue processing, the most important problem is inadequate tissue dehydration prior to paraffin embedding. This can be prevented by preparing all solutions freshly every week, depending on the volume of tissue processed. If consistently applied, these procedures could eliminate some of the sources of variation in immunohistochemical stains.

Artifacts↗
PubMed1995

Articulated external fixation of pilon fractures: the effects on ankle joint kinematics.

The effect of the Orthofix articulated ankle external fixator on ankle and subtalar joint kinematics and fracture fragment motion was investigated in fresh cadaver specimens using biplanar radiographic analysis. The kinematic testing was performed for the normal ankle (i.e., no fixation) and for three alternate fixator hinge orientations. The fixator applications simulated a horizontal ankle axis (the current clinically preferred orientation), an axis coincident with a previously defined approximate ankle axis, and an axis located using a mechanical axis finder. The horizontal fixator application significantly disturbed normal ankle kinematics. Aligning the fixator hinge with an approximate ankle axis caused significant distortion of motion about only two of six possible rotational axes. Aligning the fixator hinge with the (specimen-specific) ankle axis determined by the axis finder most closely matched the motion of the normal ankle. For pilon fractures simulated by a transverse osteotomy, there appeared to be no physiologically significant fracture fragment motions, regardless of fracture stability or fixator orientation.

Ankle Injuries↗
PubMed1997

The role of fibular fixation in combined fractures of the tibia and fibula: a biomechanical investigation.

OBJECTIVES: To determine whether adjunctive plating of the fibula with tibial fixation enhanced the stability of the construct under combined compressive and bending loads in simulated fractures of both the tibia and fibula. METHODS: Each of twelve fresh cadaveric specimens (six pairs) with an intact knee, lower extremity, and foot was mounted on the table of a materials testing machine. An intramedullary (IM) rod locked in the distal femur allowed combined compression, and flexion, valgus bending, or varus bending loads to be transmitted from the actuator of the testing machine to the knee. Three displacement measurement transducers were mounted on the tibia at anterior, posterolateral, and posteromedial positions. Intact tibial deformations under load were measured. Then, in one specimen of each pair a 2 cm osteotomy was created near the tibial midshaft, which was stabilized with an external fixator. Tibial gap displacements were measured under the following conditions: (a) intact fibula, (b) osteotomized fibula, (c) fibula fixed with a plate, (d) fibula fixed with an Enders IM nail. In the other specimen of the pair, tibial fixation was performed with an interlocked unreamed IM nail, with the same successive stages of fibular fixation. RESULTS: Osteotomy of the fibula significantly increased tibial defect motion when external fixation was used, and plating the fibula in this case significantly decreased motion. Using an Enders rod to stabilize the fibula instead of a plate, with tibial external fixation, produced smaller decreases in tibial defect site motion. With IM rod fixation of the tibia, osteotomizing the fibula had no effect on defect site motion or on its subsequent stabilization using a plate or IM rod. CONCLUSION: Plating the fibula can decrease motion across a tibial defect, but only when less rigid (i.e., external) fixation is used.

Biomechanical Phenomena↗
PubMed2007

Two-ring hybrid external fixation of distal tibial fractures: a review of 47 cases.

BACKGROUND: The healing of a metaphyseal fracture line is a major problem in cases of distal tibial fracture treated with external fixation. METHODS: Forty-seven distal tibial fractures treated with two-ring Ilizarov hybrid external fixation (16 AO/OTA type A and 31 type C, 10 open) were followed up. Fracture reduction and union time was evaluated and IOWA and RAND 36-Item Health Survey scores were used to assess functional outcome. RESULTS: Thirty-five fractures united uneventfully in a median time of 20 weeks, but 12 fractures needed additional procedures because of delayed union. According to univariate analysis, the risk factors for a longer time needed for fracture union were translational displacement and current smoking, and the risk factors for reoperation because of delayed union translational displacement fibular fracture fixation, and the number of cigarettes smoked per day. In multivariate analysis, translational displacement was a risk factor for both longer time to fracture union and reoperation and fibular fracture fixation was a risk factor for reoperation. If the translational displacement was less than 3 mm, the reoperation rate was 6%, whereas if the displacement was more than 3 mm, it was 83%. Reoperation was performed on 50% of the patients who underwent fibular fixation and on 15% of the patients who did not undergo fibular fixation. There were only marginal decreases in the range of motion and arthritis scores in the AO/OTA fracture types other than type C3. There were no significant differences in RAND 36 scores between the general Finnish population aged 18 to 64 years and our patients. CONCLUSIONS: Hybrid external fixation of distal tibial fractures is associated with delayed union, which is closely related to the degree of residual translational displacement after reduction. Fixation of an associated fibular fracture does not help to achieve better contact in the tibial fracture and increases the risk of delayed union.

Adolescent↗
PubMed1997

Fixation of various porcine arteries with an epoxy compound.

The clinical results of biological vascular grafts have been unsatisfactory. The poor results of these vascular grafts may be attributed to the fixatives, aldehydes, used in fixing tissues. In an attempt to overcome this problem, a new fixative, epoxy compound, has recently been used to fix biological vascular grafts. The study was undertaken to investigate the crosslinking characteristics, fixation index and denaturation temperature, of various porcine arteries fixed with an epoxy compound. The porcine arteries investigated in the study were the common carotid artery, internal thoracic artery, abdominal aorta, and saphenous artery. In addition, the effects of sonication on the porcine arteries before fixation on their crosslinking characteristics were analyzed. The fresh and glutaraldehyde-fixed arteries were used as controls. It was noted that glycine, proline, and alanine were the most abundant amino acids found in the porcine internal thoracic artery. In the amino acid analysis, it was observed that the amino acids in the porcine arteries reacted with epoxy compound or glutaraldehyde were lysine, hydroxylysine, histidine, and arginine. Of these amino acids, lysine was the most reactive. In general, the fixed arteries were relatively stiffer than their fresh counterparts. The fixation indices and denaturation temperatures of various porcine arteries were comparable throughout the entire fixation process. The amounts of free amino groups of the sonicated arteries were significantly lower than those of their unsonicated counterparts (p < 0.05). It is speculated that the diminishing free amino groups of the sonicated arteries may be attributed to the removal of the destroyed cell debris and adherent proteins of the arteries after sonication. However, it was learned that sonication on the porcine arteries before fixation did not seem to affect their fixation indices and denaturation temperatures. The results obtained in this study may help one in selecting the raw materials for developing a small-diameter biological vascular graft

Analysis of Variance↗
PubMed2005

Early failure of external fixation in the management of war injuries.

OBJECTIVE: To review external fixation in the management of war injuries. METHOD: We prospectively followed up 15 external fixators (14 patients) applied in the management of war injuries. All these patients were treated at 202 Field Hospital during the 2003 Gulf Conflict. RESULTS: Of the 15 fixators, 13 (86.7%) required early revision or removal due to complications of the injury or the fixator. Instability was a problem with 10 fixators (67%), pin loosening was noted with 5 fixators (33%) involving twelve pins, and a significant pin track infection developed at 14 pin sites (3 fixators - 20%), which failed to resolve despite intravenous antibiotics. CONCLUSIONS: This study demonstrates a very high early complication rate of external fixation in the management of military injuries and cautions against its universal acceptance. If used, consideration must be given to the optimum time of frame application, whether at the time of initial debridement or at a later operation, and the optimal frame design, which will depend on the specific bone and fracture pattern. Pin site care must also be considered, particularly with the restrictions imposed by the military environment.

Adolescent↗
PubMed2004

Intra-articular fractures of the tibial plafond. A comparison of the results using articulated and ring external fixators.

We retrospectively reviewed 60 fractures of the tibial plafond treated by either an ankle-sparing diaphyseal-epiphyseal technique using the Ilizarov ring fixator or by an ankle-spanning technique using a monolateral articulated external fixator. The Ilizarov ring fixator was applied in 24 fractures and the monolateral articulated transarticular external fixator in 20. Both techniques were combined with limited open reduction and internal fixation of the articular surface if necessary. Between three and nine years after the injury, all patients returned for clinical and radiological assessment and evaluation of ankle function using the modified Mazur score. There were no significant differences between the two groups in terms of age, gender, mechanism of injury, type of fracture or length of follow-up. The mean functional ankle score was 86 points for the Ilizarov group and 82 points for the articulated fixator group. The difference was not significant (p = 0.07). There were no significant differences between the groups with regard to the radiographic score and late complications. Patients treated with the Ilizarov ring fixator had significantly better ankle and subtalar movement. We conclude that both techniques of external fixation are satisfactory methods of treatment for fractures of the tibial plafond, but that the total arc of movement of the joint is preserved better without bridging the ankle.

Adult↗
PubMed2002

A biomechanical analysis of fixation of intra-articular distal radial fractures with calcium-phosphate bone cement.

BACKGROUND: Calcium phosphate cement has been used to treat unstable fractures of the distal end of the radius with the intent of avoiding the stiffness and morbidity associated with prolonged immobilization in a cast or external fixation. The purpose of this study was to compare the stability of the fracture fragments after fixation with augmented calcium phosphate cement with that after alternative methods of percutaneous fracture treatment. METHODS: Both an osteotomy and osteoclasis were used to create a model of an intra-articular fracture of the distal part of the radius (AO type C2) with dorsal bone loss in seven pairs of fresh-frozen upper extremities. One wrist from each pair was fixed with an external fixator and three Kirschner wires, and the contralateral wrist was fixed with calcium phosphate cement (Norian SRS) and three Kirschner wires (augmented calcium phosphate cement). Sequentially increasing loads, up to a total of 100 N, were then applied to the major flexors and extensors of the wrist. Fracture fragment motion was measured by the Optotrak three-dimensional system. RESULTS: Fixation with cement alone failed at the bone-cement interface at <80 N in all specimens. With use of an analysis of variance, augmented external fixation was found to provide significantly increased stability to the radial fragment compared with that provided by augmented calcium phosphate cement in four of the six axes tested (e.g., mean motion [and standard deviation] in flexion-extension was 3.0 degrees +/- 2.93 degrees versus 11.1 degrees +/- 13.08 degrees, respectively; p = 0.001). Augmented calcium phosphate cement was found to provide greater stability for the radial fragment than were Kirschner wires alone in three axes (e.g., mean motion in flexion-extension was 11.1 degrees +/- 13.08 degrees versus 36.5 degrees +/- 13.03 degrees, respectively; p = 0.001). CONCLUSIONS: Calcium phosphate cement alone is insufficient to withstand physiologic flexion-extension motion of the wrist without supplemental wire fixation. When supplemented with Kirschner wires, fixation with bone cement is more stable than are Kirschner wires alone, but it is significantly less stable than augmented external fixation.

Biomechanical Phenomena↗
PubMed2005

[External skeletal fixation of the tibial shaft fractures].

AIM: To present the possibility of a succesfful use of external skelatal fixation in treating the open and closed tibial shaft fractures with Mitković's external fixator. METHODS: External fixation was used in 115 patients with 118 fresh tibial shaft fractures, 82 males (71.3%) and 33 females (28.7%), average age 43.92 years (16-84). Open tibial shaft fractures were present in 37 (31.36%). All the fractures were treated with Mitković's external fixator type M 20. RESULTS: The results of external fixation were excellent or good in 94.07% of the cases, and bad in 5.08%. Pin tract infection appeared in 7 (5.93%) patients. In only 3 cases an external fixator was removed and treatment continued with the functional braces. Nonunion occurred in 6 (5.08%) patients, of which 4 were with open fractures (2 Gustilo type IIIB, 1 Gustilo type IIIA, 1 Gustilo type II) and 2 with the segment fractures. Compartment syndrome was observed in 1 (0.85%) patient with closed fracture. Malunion was found in 2 (1.69%) patients. CONCLUSION: External fixation of tibial shaft fractures is a simple and effective method to enable the safe healing of fractures, early mobilization of the patients, early weight-bearing, as well as early rehabilitation. Fixation of tibial shaft fractures was unilateral with convergent pins orientation, and there was also a possibility of compression and distraction.

Adolescent↗
PubMed1999

The effect of fixation on detection of B-cell clonality by polymerase chain reaction.

It has been suggested that neutral buffered formalin (NBF)-fixed, paraffin-embedded, or fresh specimens might provide satisfactory DNA templates for polymerase chain reaction (PCR) assays used in establishing the clonality and presumptive B-cell lineage of lymphoma. The suitability of other fixatives used by hematopathologists, such as B5, is still undetermined. Thirty cases were identified from the files of the Cleveland Clinic Foundation, Cleveland Ohio, that showed abnormal immunoglobulin heavy chain (IgH) rearrangement by Southern blot analysis (SBA). Corresponding paraffin-embedded tissue samples fixed in NBF (21 cases), B5 (18 cases), Hollande's fixative (17 cases), zinc formalin (ZF) (5 cases), and Bouin's fixative (3 cases) were studied. With use of consensus primers against the framework 3 (FR3) and FR2 regions of the VH gene, paired against JH primer(s), PCR analysis was performed. bcl-2/IgH translocation was also studied. Ten reactive lymphoid samples were used as controls, and 40 cases were evaluated. Successful amplification of a clonal proliferation was manifested as one or two discrete narrow bands in the appropriate size range. The sensitivity of detecting clonality was 95, 94, 67, 80, and 0% for NBF, Hollande's fixative, B5, ZF, and Bouin's fixative, respectively. Although NBF and Hollande's fixative were 100% specific, consistent false-positive results were a major problem with B5-fixed tissue. Paraffin-embedded tissue, fixed in NBF, Hollande's fixative, and ZF solutions, may be used for DNA extraction and PCR assays for establishing B-cell clonality. The precipitating fixative B5 and Bouin's solution should not be used for this purpose until the issue of false-positive results is resolved.

B-Lymphocytes↗