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At least 199 records · Page 11Linked to original sources
PubMed2005

Complex tibial plateau fractures treated with Ilizarov external fixator with or without minimal internal fixation.

We treated 30 tibial plateau fractures (Schatzker Type VI) in 29 patients, with a mean age of 41.4 (20-76) years, with the Ilizarov fixator. In 18 fractures, we combined the treatment with minimal internal fixation. All fractures were the result of high-energy trauma, and 20 patients had associated injuries. Twenty-eight fractures were available for follow-up after 27 (16-36) months. Using The Knee Society clinical rating system, 18 knees were rated as excellent, seven as good, one as fair, and two as poor. There was a direct correlation between the presence of associated injuries and the final outcome. The most significant concomitant injuries were distal femoral fractures and extensive soft-tissue injury. This study emphasizes the clinical success and low morbidity associated with the use of external fixation and minimal internal fixation.

Adult↗
PubMed2006

The olecranon sled--a new device for fixation of fractures of the olecranon: a mechanical comparison of two fixation methods in cadaver elbows.

BACKGROUND: Tension band wiring is the most common surgical procedure for fixation of fractures of the olecranon, but symptomatic hardware prominence and migration of K-wires can cause a high re-operation rate. The olecranon sled has been designed to minimize some of these problems. MATERIAL AND METHODS: Simulated olecranon fractures were created in 6 matched pairs of cadaver arms. Each pair was fixed with tension band wiring used on the one arm and the olecranon sled being used on the other. Mechanical testing was done with the humerus rigidly fixed in a vertical position while the forearm was held at 1 of 3 angles of elbow fixation, 45 degrees , 90 degrees and 135 degrees , respectively. For each angle, the triceps and the brachialis muscles were sequentially loaded with 5 kg (50 N) for 20 cycles and the amount of fracture displacement measured. RESULTS: Loading of the brachialis muscle produced no increase in the fracture gap for either of the two fixation techniques. However, an increase in the fracture gap of up to 0.23 mm was found after cyclic loading of the triceps muscle for both techniques. The amount of increase was not significantly different between the two techniques. INTERPRETATION: The olecranon sled appears to provide as stable fixation as tension band wiring for olecranon fractures.

Adult↗
PubMed1995

The use of combination internal fixation and hybrid external fixation in severe proximal tibia fractures.

Forty-eight patients with 50 severe fractures of the proximal tibia were followed prospectively for 2-4 years (mean 2.7 years) to evaluate the use of limited internal fixation combined with external fixation in the treatment of these injuries. There were 27 men and 21 women ranging in age from 20 to 74 years. Fractures were classified according to the A0 system (Mast J, Ganz R, Jacob R: Planning and reduction technique in fracture surgery. Berlin, Springer-Verlag, 1989), which included 5 A3, 6 C1, 16 C2, and 23 C3 fractures. All patients in this series healed; 48 fractures healed in an average of 12 weeks without subsequent surgery. There were two (4%) nonunions requiring bone graft. The average hospital special surgery knee score was 90 (68-100). Grading criteria for anatomical outcome revealed there were 17 (34%) excellent results, 24 (48%) good results, 6 (12%) fair results, and 3 (6%) poor results. In conclusion, this treatment method is associated with a high percentage of good and excellent results. Combined internal and external fixation combines the advantages of anatomic, stable fixation with less soft-tissue dissection and eliminates the need for large implants.

Adult↗
PubMed2005

Indirect reduction and percutaneous fixation versus open reduction and internal fixation for displaced intra-articular fractures of the distal radius: a randomised, controlled trial.

A total of 179 adult patients with displaced intra-articular fractures of the distal radius was randomised to receive indirect percutaneous reduction and external fixation (n = 88) or open reduction and internal fixation (n = 91). Patients were followed up for two years. During the first year the upper limb musculoskeletal function assessment score, the SF-36 bodily pain sub-scale score, the overall Jebsen score, pinch strength and grip strength improved significantly in all patients. There was no statistically significant difference in the radiological restoration of anatomical features or the range of movement between the groups. During the period of two years, patients who underwent indirect reduction and percutaneous fixation had a more rapid return of function and a better functional outcome than those who underwent open reduction and internal fixation, provided that the intra-articular step and gap deformity were minimised.

Adolescent↗
PubMed1975

Biochemical aspects of aldehyde fixation and a new formaldehyde fixative.

In this paper, it is assumed that tissue fixation is a process in which the proteins become less soluble and catabolic reactions stop. With this definition in mind, 2.5 and 5% glutaraldehhde and 4% formaldehyde in 0.1 M potassium phosphate buffer, pH 7.4, were compared with a new fixative, bicarbonate-formaldehyde. The following results were obtained. (I) With 2.5 and 5% glutaraldehyde, the solubility of tissue proteins were not decreased unifromly, and tissue glycogen was poorly preserved. (2) 4% formaldehyde in potassium phosphate buffer gave relatively good results. (3) Bicarbonate-formaldehyde decreased the solubility of tissue proteins reliably and preserved tissue glycogen perfectly. Histologically, it yielded excellent results. Since glutaraldehyde alters the properties of proteins substantially (Hopwood, 1972; Habeeb & Hiramoto, 1968), and since the natural appearance of tissues depends on native tissue proteins, formaldehyde-containing fixatives, in particular bicarbonate-formaldehyde, are preferable to glutaraldehyde-containing fixatives for all tissue preparative techniques. However, it is important that the fixation time in formaldehyde is kept short.

Aldehydes↗
PubMed2004

Graft healing in a bone tunnel: bone-attached graft with screw fixation versus bone-free graft with extra-articular suture fixation.

The purpose of this study was to clarify differences in tendon graft-to-bone tunnel healing between bone-attached tendon grafts with interference-screw fixation and bone-free tendon grafts with extra-articular suture fixation. In 42 Japanese White rabbits, anterior half replacement of the medial collateral ligament was performed using half of the ipsilateral patellar tendon. At the femoral attachment, the bone-plug-attached graft was fixed with an interference screw (group A). The bone-plug-free graft was fixed by the extra-articular suture fixation technique with sutures tied over a button (group B). Biomechanical and histological evaluations were performed at 2, 4 and 8 weeks postoperatively. In biomechanical evaluation, at 2 or 4 weeks 27 of 28 specimens (96%) were pulled out from the femoral tunnel, while one 4-week specimen and all four 8-week specimens failed at the graft's mid-substance. At 2 weeks, the maximum failure load was 25+/-10 N and 24+/-6 N for group A and group B respectively (mean+/-SD). At 4 weeks, the maximum failure load was 42+/-17 N and 35+/-15 N respectively. There were no significant differences in maximum pullout failure load between the groups at 2 or 4 weeks postoperatively. (P=0.887 at 2 weeks and P=0.339 at 4 weeks using ANOVA measurement). Histologically, the bone-attached grafts showed partial bone-to-bone union at the graft-bone tunnel interface at 4 weeks, and complete bony union at 8 weeks. The bone-free grafts exhibited newly formed Sharpey-like collagen fibers at 4 weeks, and strong connection by mature granulation tissue at 8 weeks. Graft-to-bone tunnel healing of bone-attached graft with screw fixation and bone-free graft with extra-articular suture fixation are comparable in terms of biomechanical evaluation during the early postoperative periods.

Animals↗
PubMed1997

Cyclic loading of anchor-based rotator cuff repairs: confirmation of the tension overload phenomenon and comparison of suture anchor fixation with transosseous fixation.

Previous experimental studies of failure of rotator cuff repair have involved single pull to ultimate load. Such an experimental design does not represent the cyclic loading conditions experienced in vivo. We created 1 x 2 cm rotator cuff defects in 16 cadaver shoulders, repaired each defect with three Mitek-RC suture anchors (Mitek Surgical Products, Inc, Westwood, MA) using simple sutures of No. 2 Ethibond, and cyclically loaded the repairs by a servohydraulic materials test system actuator at physiological rates and loads (rate of 33 mm/s, load 180 N). A progressive gap was noted in each specimen, for a 100% rate of failure of the repairs. The central suture always failed first and by the largest magnitude, confirming tension overload centrally. One specimen exhibited combined bone and tendon failure, but the other 15 specimens failed through the tendon. Overall, the repairs failed to 5 mm and 10 mm at an average of 61 cycles and 285 cycles, respectively. Half the specimens were less than 45 years of age and had a 5-mm and 10-mm failure at an average of 107 and 478 cycles, respectively. The other half were over 45 years of age and failed to 5 mm and 10 mm at an average of 17 and 91 cycles, respectively, indicating more rapid failure of the rotator cuff tendons in the older group, and this was statistically significant (P < or = .02). Comparison of suture anchor fixation in this study with transosseous bone tunnel fixation in a previous cyclic loading study at this institution indicates that bone fixation by suture anchors is significantly less prone to failure than bone fixation through bone tunnels (P = .0008). Changing the bone fixation from bone tunnels to suture anchors effectively transferred the weak link from bone to tendon.

Adolescent↗
PubMed2000

The effect of diaphyseal biologic fixation on clinical results and fixation of the APR-II stem.

This study evaluated the effect of a grit-blasted diaphyseal surface on noncemented fixation of the Anatomic Porous Replacement II stem (APR-II, Sulzer Medica Orthopaedics, Austin, TX) for improvement of clinical results and fixation. A total of 107 consecutive total hip arthroplasties with the APR-II stem, which has proximal porous coating and a diaphyseal grit-blasted surface, were performed without cement, and 99 were studied at average 4 years. Of these hips, 37 had hydroxyapatite sprayed onto the proximal porous coating, but because there were no statistical differences for performance in any category, all stems were considered as 1 group. Clinical results were measured by the Harris hip score. Radiographic measurements of fixation, osteolysis, and bone remodeling were studied by reference to Gruen zones. Of hips, 99% had a good or excellent result by Harris hip score, with an average pain score of 42.3. Of hips, 98% had >40 points, with no patient reporting thigh pain after 3 years. There were no radiolucent lines in 94% of stems, and 100% had proximal bone ingrowth fixation. Distal cortical hypertrophy associated with tip fixation occurred in 49%, whereas proximal stress shielding was present in 43% of hips. Comparison of these clinical and radiographic results with our previous experience of bone ingrowth implants (smooth stem) suggests that bone ingrowth proximally with ongrowth in the diaphysis of the femoral stem provides better clinical and radiographic results.

Arthroplasty, Replacement, Hip↗
PubMed1999

Comparison of tricortical screw fixation versus a modified suture construct for fixation of ankle syndesmosis injury: a biomechanical study.

OBJECTIVE: To assess the viability of using a modified flexible suture implant instead of a tricortical screw for fixation of ankle syndesmosis failures. DESIGN: Randomized biomechanical study. SETTING: Orthopaedic Research Laboratories at the University of North Carolina at Chapel Hill. INTERVENTION: Formalin-preserved cadaveric legs were used in pairs. Two holes, 2.5 millimeters in diameter and 7.0 to 10.0 millimeters apart horizontally, were drilled through the fibula and tibia 2.0 centimeters above the tibial plafond. Two strands of Number 5 suture were passed through the holes and tied. Similarly, a 3.5-millimeter tricortical screw was placed on the opposite leg of each pair at 2.0 centimeters. The ankles were tested to failure. This process was repeated at 5.0 centimeters above the tibial plafond. MAIN OUTCOME MEASUREMENTS: Maximum load and displacement at failure of the suture construct at 2.0 centimeters and at 5.0 centimeters were compared with a tricortical screw at 2.0 centimeters and at 5.0 centimeters. RESULTS: There was no significant difference in strength or displacement between the flexible suture implant and the tricortical screw at either 2.0 centimeters or 5.0 centimeters. The fixations at 5.0 centimeters had significantly increased holding strength over fixations at 2.0 centimeters, and the fixations had significantly greater displacement at 2.0 centimeters than at 5.0 centimeters. CONCLUSION: This study confirms that flexible syndesmosis repair is a viable option for internal fixation of ankle mortise instability due to syndesmosis rupture.

Ankle Injuries↗
PubMed1992

Screw fixation in the human sacrum. An in vitro study of the biomechanics of fixation.

A load-to-failure test was used to study the biomechanical properties of sacral screw fixation in human cadaveric specimens. The goals of this study were 1) to determine the effects of the two commonly chosen sacral screw orientations of fixation characteristics; 2) to determine the effects of selected screw-instrumentation linkages on the biomechanics of sacral screw fixation; 3) to correlate the biomechanical properties with a noninvasive assessment of sacral bone density; and 4) to correlate the torque during screw insertion with these biomechanical properties. The bone density of each specimen was measured with quantitative computed tomography. A screw was inserted from the dorsal surface either anteromedially or anterolaterally into the body of S1, and the torque needed to insert each screw was measured. The screw head was attached to a constrained or semiconstrained loading linkage. Force was applied to the screw in an inferior direction until the maximum load was achieved. The maximum load, screw translation, rotation at maximum load, and initial compliance of the bone-screw interface were determined. It was found that the anteromedial screw orientation, combined with a rigidly constrained loading linkage, resulted in the greatest maximum load to failure, the least screw rotation, and the least initial compliance of the four groups studied. The maximum load and the initial stiffness of bone-screw fixation increased significantly with bone density. Torque measurements correlated significantly with maximum load to failure, initial interface stiffness, and bone density. It was therefore concluded that bone density and torque measurements can be useful in assessing sacral screw fixation.

Aged↗
PubMed1977

Carbon Dioxide Fixation by Lupin Root Nodules: I. Characterization, Association with Phosphoenolpyruvate Carboxylase, and Correlation with Nitrogen Fixation during Nodule Development.

In vivo CO(2) fixation and in vitro phosphoenolpyruvate (PEP) carboxylase levels have been measured in lupin (Lupinus angustifolius L.) root nodules of various ages. Both activities were greater in nodule tissue than in either primary or secondary root tissue, and increased about 3-fold with the onset of N(2) fixation. PEP carboxylase activity was predominantly located in the bacteroid-containing zone of mature nodules, but purified bacteroids contained no activity. Partially purified PEP carboxylases from nodules, roots, and leaves were identical in a number of kinetic parameters. Both in vivo CO(2) fixation activity and in vitro PEP carboxylase activity were significantly correlated with nodule acetylene reduction activity during nodule development. The maximum rate of in vivo CO(2) fixation in mature nodules was 7.9 nmol hour(-1) mg fresh weight(-1), similar to rates of N(2) fixation and reported values for amino acid translocation.The results suggest that the oxaloacetete used as the primary "carbon skeleton" acceptor for ammonia assimilation and amino acid synthesis in lupin nodules is provided via the PEP carboxylase reaction rather than through the tricarboxylic acid cycle. The source of PEP is presumably glycolysis, while the major source of CO(2) is inferred to be respiration.

Journal Article↗
PubMed1981

Carbon Dioxide Fixation in Soybean Roots and Nodules: I. CHARACTERIZATION AND COMPARISON WITH N(2) FIXATION AND COMPOSITION OF XYLEM EXUDATE DURING EARLY NODULE DEVELOPMENT.

These studies demonstrate that soybean (Merr) roots and nodules possess an active system for fixing CO(2). The maximum rates of CO(2) fixation observed for roots and nodules of intact plants were 120 and 110 nanomoles CO(2) fixed per milligram dry weight per hour, respectively. Results of labeling studies suggest a primary role for phosphoenolpyruvate carboxylase in CO(2) assimilation in these tissues. After pulse-labeling with (14)CO(2) for 2 minutes, 70% of the total radioactivity was lost within 18 minutes via respiration and/or translocation out of nodules. During the vegetative stages of growth of soybeans grown symbiotically, CO(2) fixation in nodules increased at the onset of N(2) fixation but declined to a lower level prior to the decrease in N(2) fixation. This decrease coincided with a decrease in the transport of amino acids, especially asparagine, and an increase in the export of ureides. These findings are consistent with a dual role for CO(2) fixation, providing substrates for energy-yielding metabolism and supplying carbon skeletons for NH(4) (+) assimilation and amino acid biosynthesis.

Journal Article↗
PubMed2004

Interference screw fixation of soft tissue grafts in anterior cruciate ligament reconstruction: part 1: effect of tunnel compaction by serial dilators versus extraction drilling on the initial fixation strength.

BACKGROUND: Compaction of the bone-tunnel walls by serial dilation is believed to enhance the interference screw fixation strength of the soft tissue grafts in anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS: Serial dilation enhances the fixation strength of soft tissue grafts in ACL reconstruction over extraction drilling. STUDY DESIGN: Randomized experimental study. METHODS: Initial fixation strength of the doubled anterior tibialis tendon grafts (fixed with a bioabsorbable interference screw) was assessed in 21 pairs of human cadaver tibiae with either serially dilated or extraction-drilled bone tunnels. The specimens were subjected to a cyclic-loading test, and those surviving were then tested using the single-cycle load-to-failure test. RESULTS: During the cyclic-loading test, there were 3 fixation failures in the serially dilated and 6 failures in the extraction-drilled specimens but no significant stiffness or displacement differences between the groups. In the subsequent load-to-failure test, the average yield loads were 473 +/- 110 N and 480 +/- 115 N for the 2 groups respectively (P =.97) and no difference with regard to stiffness or mode of failure. CONCLUSIONS: Serial dilation does not increase the strength of interference fixation of soft tissue grafts in ACL reconstruction over extraction drilling. CLINICAL RELEVANCE: The results of this experiment do not support the use of serial dilators in ACL reconstruction.

Adolescent↗
PubMed1993

The Miller-Galante knee prosthesis for the treatment of osteoarthrosis. A comparison of the results of partial fixation with cement and fixation without any cement.

In a prospective, non-randomized study of 344 patients who had 392 primary total knee replacements with a Miller-Galante I prosthesis for the treatment of osteoarthrosis, the results of partial fixation with cement (insertion of the tibial and patellar components with cement and of the femoral component without cement) were compared with those of fixation without any cement. Of the 392 knees, 183 (163 patients) had fixation without cement (Group I) and 209 (181 patients), with and without cement (Group II). The average duration of follow-up was three years (range, two to five years). Nine patients died during the follow-up period, but no others were lost to follow-up. Analysis of the knee scores, range of motion of the knee, radiographs, and rates of complications revealed no differences between the outcomes in the two groups during the follow-up period. The rate of complications due to problems related to the extensor mechanism was high in both groups: a reoperation was performed in fifteen (8 per cent) of the knees that had had fixation without cement and in nineteen (9 per cent) of those that had had both types of fixation. Thirteen patients had additional operative treatment for recurrent patellar dislocations; twelve patients, for abnormal wear of the polyethylene of the patellar component: two patients, for avulsion of the patellar ligament from the tibia; and two patients, for unexplained pain in the knee. In addition, there were eight patellar fractures (two of which led to a reoperation) and three deep infections (all of which led to a reoperation).

Adult↗
PubMed2006

Biomechanical comparison of two new atlantoaxial fixation techniques with C1-2 transarticular screw-graft fixation.

OBJECT: Two new techniques for atlantoaxial fixation have been recently described. In one technique, C-2 intralaminar screws are connected with C-1 lateral mass screws; in the second, C-1 and C-3 lateral mass screws are interconnected and C-2 is wired sublaminarly. Both techniques include a C1-2 interspinous graft. The authors compared these techniques with the gold-standard, interspinous graft-augmented C1-2 transarticular screw fixation and with a control C1-2 interspinous graft fixation procedure alone. METHODS: In six human cadaveric occiput-C4 specimens, nonconstraining 1.5-Nm pure moments were applied to induce flexion, extension, lateral bending, and axial rotation during which three-dimensional angular motion was measured optoelectronically. Each specimen was tested in the normal state, with graft alone (after odontoidectomy), and then in varying order after applying each construct with a rewired graft. All three constructs allowed significantly less angular motion at the C1-2 junction than the wired interspinous graft alone during lateral bending and axial rotation (p < 0.01, paired Student t-test) but not during flexion or extension. Transarticular screw fixation with an interspinous graft allowed less motion at the atlantoaxial junction than the two new constructs in several conditions. Differences were greater between the transarticular screw construct and the intralaminar screw construct than between the transarticular screw construct and the C1-3 lateral mass screw construct. During lateral bending and axial rotation, the C1-3 construct allowed less motion at the atlantoaxial junction than the intralaminar screw construct. CONCLUSIONS: Biomechanically, the gold-standard C1-2 transarticular screw fixation outperformed the two new techniques during lateral bending and axial rotation. Wiring C-2 to C1-3 rods provided greater stability than C1-2 laminar screws, but it sacrificed C2-3 mobility. It is unknown whether the small differences observed biomechanically would lead to clinically relevant differences in fusion rates.

Aged↗
PubMed1989

Experimental spiral fractures. An in vitro biomechanical comparison of lag-screw fixation to plate fixation.

The rigidity and strength of fixation of experimental spiral fractures in canine tibias with triple lag-screw osteosynthesis were compared with fixation by six-hole dynamic compression plating (DCP). Lag-screw fixation was 71% to 77% as stiff in bending and 69% as stiff in torsion as plate fixation. When evaluated by torsion to failure, lag-screw specimens were 68% as strong as plate specimens. Although the difference in energy to failure in torsion was not statistically significant between the two methods, both fell considerably short of control values. The lag preparation was 9% as strong as intact controls, and the plate preparation was 21% as strong as intact controls. Long spiral fractures without comminution are amenable to triple lag-screw osteosynthesis with some loss of rigidity and strength when compared to single-plate fixation. This decrease in rigidity and strength may be outweighed by the avoidance of the stress protection phenomenon noted under rigid plates.

Animals↗
PubMedDate not supplied

[Kinetics of sodium thiosulfate-35S fixation and effect of some sulfur compounds on iodine-131 fixation in ray thyroid gland].

In order to invalidate or confirm the affirmation that non antithyroid sulphide molecules alter the measure of the thyroid fixation rate of iodine 131 we undertook on the rat: on one hand a kinetic study of thyroid fixation of sodium thiosulfate labelled with sulphur 35, which showed a very low captation not exceeding 0,01% of injected radioactivity; on the other hand the study of the effects of some sulphide molecules on thyroid fixation of iodine 131 in the rat: sodium thiosulfate, association of sodium thiosulfate + metalloidal sulphur + methionine, carbutamide and dimethylsulfoxyde in various kinds of dose administration and periods. None of the products used in our work conditions produced a significant decrease of the fixation rate of iodine 131. In three different experimental protocols (sulfur association and dimethylsulfoxide), we showed a significant light increase of the fixation rate.

Animals↗
PubMed2005

Complications encountered while using thin-wire-hybrid-external fixation modular frames for fracture fixation. A retrospective clinical analysis and possible support for "Damage Control Orthopaedic Surgery".

One hundred ninety eight adult patients who had sustained long bone fractures were treated by external fixation from admission to bone healing and consolidation. Of these, 135 had sustained high-energy injuries, 39 of them had suffered multi-system injuries. Superficial pin track infection was the most common complication, occurring predominantly in pins located in the femur, upper tibia and upper humerus. There were no cases of deep infection or osteomyelitis. One patient with a femoral shaft fracture developed a DVT although he was on preventive low molecular weight heparin, i.e. sc Clexane 40 mg daily. There were no cases of PE or ARDS. External fixation systems are a minimal invasive surgical modality, which allow three-dimensional fracture fixation after closed or minimal open reduction. They require a good command of surgical anatomy, but provide an optimal preservation of the fracture's soft tissue envelope, the critical biological factor for new bone formation and fracture healing. Recent publications have suggested that in the critically ill patient, minimally invasive fracture fixation surgery may prevent the perpetuation of a reactive, life threatening inflammatory reaction (the "second hit") which may induce the development of multiple organ dysfunction (MODS).

Adult↗