Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Fixatives”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2000

Extramedullary fixation implants for extracapsular hip fractures.

BACKGROUND: Extramedullary fixation of hip fractures refers to the application of a plate and screws to the lateral side of the proximal femur. OBJECTIVES: To compare different types of extramedullary fixation implants for the surgical treatment of extracapsular hip fracture in adults. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group trials register and reference lists of relevant articles. Date of the most recent search: March 1998. SELECTION CRITERIA: All randomised or quasi-randomised trials comparing extramedullary implants used in the fixation of extracapsular hip fracture in adults. DATA COLLECTION AND ANALYSIS: All three reviewers independently assessed trial quality, using a ten item scale, and extracted data. Additional information was sought from all trialists. Wherever appropriate and possible, results of outcome measures were pooled by comparison. MAIN RESULTS: The methodological quality of all six included trials was poor and in no trial was there clear concealment of allocation. Three trials involving 355 patients compared a fixed nail plate (Jewett or McLaughlin) with the sliding hip screw (SHS). The limited data presented indicated an increased risk of fixation failure outcomes for fixed nail plates. One trial involving 233 patients compared the RAB plate (a fixed angle blade plate with an oblique connecting strut) with the SHS. In this trial both implants had a high incidence of fixation failure. There was a tendency to a lower incidence of cut-out, re-operation, fixation failure, leg shortening, varus deformity and mortality for the RAB plate. None of the differences in these outcomes were statistically significant. One trial involving 100 patients compared the Pugh nail and the SHS. There was no significant difference between implants for the outcome measures reported. One trial involving 176 patients with 182 fractures, compared the Medoff plate with the SHS. A significantly higher mean operative blood loss and longer mean operative time were reported for the Medoff plate. There was however a tendency to a lower risk of fixation failure for unstable trochanteric fractures fixed with the Medoff plate. REVIEWER'S CONCLUSIONS: The fixed nail plate was demonstrated to have to an increased risk of implant breakage and fixation failure in comparison to the SHS. Although the lack of evidence from randomised trials for other outcomes means that a firm conclusion of overall superiority of the SHS cannot be made, the increased fixation failure rate is a major consideration and indicates that the SHS is preferable. Insufficient information is available to draw firm conclusions of the clinical significance of differences between the SHS and either the RAB plate, the Pugh nail or the Medoff plate.

Bone Plates↗
PubMed2000

Fixation of biological tissues with a naturally occurring crosslinking agent: fixation rate and effects of pH, temperature, and initial fixative concentration.

In an attempt to overcome the cytotoxicity problem of the glutaraldehyde-fixed tissues, a naturally occurring crosslinking agent (genipin) was used by our group to fix biological tissues. The study was intended to investigate the rate of tissue fixation by genipin. Glutaraldehyde was used as a control. In addition, the degrees of tissue fixation by genipin at different pHs (pH 4.0, pH 7. 4, pH 8.5, or pH 10.5), temperatures (4 degrees C, 25 degrees C, 37 degrees C, or 45 degrees C), and initial fixative concentrations (0.250%, 0.625%, or 1.000%) were examined. The results obtained revealed that the rate of tissue fixation by glutaraldehyde was significantly faster than that by genipin. The degree of tissue fixation by genipin may be controlled by adjusting its fixation duration or fixation conditions. The order in degree of tissue fixation by genipin at different pHs, from high to low, was: at nearly neutral pH (pH 7.4 or pH 8.5) > at basic pH (pH 10.5) > at acidic pH (pH 4.0). The degrees of tissue fixation by genipin at different temperatures were about the same, except for that at 4 degrees C. In contrast, the initial fixative concentration did not seem to affect the degree of tissue fixation by genipin, if only the amount of genipin in the fixation solution was sufficient to complete tissue fixation. The concentrations of genipin in the aqueous solutions at different pHs, temperatures, and initial fixative concentrations tended to decrease with time with or without the occurrence of tissue fixation. This indicated that genipin was not stable in the aqueous solution. The instability of aqueous genipin was more remarkable with increasing pH or temperature. The results obtained in this study may be used to optimize the fixation process for developing bioprostheses fixed by genipin.

Animals↗
PubMed2005

Biomechanical comparison of lumbosacral fixation using Luque-Galveston and Colorado II sacropelvic fixation: advantage of using locked proximal fixation.

STUDY DESIGN: Biomechanical evaluation of sacropelvic fixation strategies as they apply to neuromuscular scoliosis. OBJECTIVES: The primary objective was to compare the rigidity of 2 methods of sacropelvic fixation (Galveston vs. Colorado II). The secondary objective was to evaluate the effect on construct rigidity by adding a pair of L1 pedicle screws to a Luque wire construct. SUMMARY OF BACKGROUND DATA: The Galveston modification to the Luque rodding system has become standard for treating childhood and adolescent neuromuscular scoliosis. The Galveston method provides reasonable lumbo-pelvic fixation with a relatively simple method of insertion. Clinical reviews of sagittal plane stability in neuromuscular patients with Galveston fixations performed at our institution have led to concerns regarding the technique's ability to maintain proper lumbar lordosis. This concern has generated interest in evaluating biomechanical stability of more rigid fixation methods in these long spino-pelvic constructs. As such, the following biomechanical study evaluated lumbosacral stability of 2 sacropelvic fixation methods: the standard Luque-Galveston method and the Colorado II sacropelvic fixation method using the Chopin plate-screw block. As a secondary interest, evaluations of the rigidity of the proximal construct when using pedicle screw fixation were completed. It was hypothesized that one additional point of rigid fixation at the thoracolumbar junction may make substantial improvement in rigidity to the otherwise Luque construct. METHODS: Lumbo-pelvic segments of human cadaveric specimens were instrumented with L1 pedicle screws, sublaminar wires between L2 and L5, and sacropelvic fixation with either Galveston rods or Colorado II sacropelvic plates using S1 screws, S2 alar screws, and iliac screws. Tests were conducted for physiologic flexion-extension and torsional loading. Construct stiffness between L1-S1 was determined for each specimen. Motion measurement data were collected between L1-L5 and L5-S1 using a noncontact marker system. Statistical analysis included a 2 -way analysis of variance (dependent variables: construct/locked screw) with the Tukey post hoc correction for multiple comparisons (P < 0.05). RESULTS: The flexion and extension bending stiffness of the construct was similar between the Galveston and Colorado II constructs. Both constructs were stiffer when the L1 screws were locked rigidly to the rod. Torsional stiffness followed similar trends with no significant difference between the systems, although more rigid in more cases when the L1 screws were locked to the rod. Regarding limiting L5-S1 motion during flexion and extension loading, the Colorado II construct did so to a higher degree. There was no difference in torsional motion between the 2 constructs. Locking the L1 pedicle screws reduced torsional motion but had no effect on flexion-extension motion at L5-S1. CONCLUSION: The 2 methods of sacropelvic fixation provided similar construct stiffness, although the Colorado II method had less L5-S1 motion on flexion-extension testing, and the Galveston construct tended (although not statistically) to be stiffer in torsional loading. The addition of a pair of L1 pedicle screws increased the construct stiffness for both constructs by approximately 50%.

Biomechanical Phenomena↗
PubMedDate not supplied

Initial fixation strength of two bioabsorbable pins for the fixation of hamstring grafts compared to interference screw fixation: single cycle and cyclic loading.

BACKGROUND: During the early postoperative period, the fixation of a hamstring graft to the bone tunnel is the primary factor in limiting rehabilitation. HYPOTHESIS: The initial fixation strength of a double cross pin fixation technique is comparable with the biodegradable interference screw fixation technique. STUDY DESIGN: Experimental laboratory study. METHODS: The authors examined the initial fixation strength of two 3.3-mm bioabsorbable pins compared to interference screws for hamstring grafts in bovine knees. RESULTS: Analysis of yield load, maximum load, and stiffness in the single-cycle loading test showed no statistically significant differences for cross pin and interference fixation (P <.05). For cross pins and interference screws, the mean displacement under 1000 cycles to 250 N was 5.07 ( +/- 1.9) mm and 4.81 ( +/- 2.5) mm, stiffness 252 ( +/- 78) N/mm and 289 ( +/- 148) N/mm. Only grafts fixed with cross pins survived 1000 cycles to 450 N. CONCLUSION: The initial fixation strength of the double cross pin technique is comparable to that of interference screw fixation with a stiffness comparable to that of the native ACL. CLINICAL RELEVANCE: Hamstring graft fixation using two cross pins provides an alternative to bioabsorbable interference screw fixation.

Absorbable Implants↗
PubMed2005

A randomized prospective study on the treatment of intra-articular distal radius fractures: open reduction and internal fixation with dorsal plating versus mini open reduction, percutaneous fixation, and external fixation.

PURPOSE: To compare 2 methods of surgical treatment for displaced intra-articular fractures of the distal radius: open reduction and internal fixation with dorsal plating (Pi Plate; Synthes, Paoli, PA) versus mini open reduction with percutaneous K-wire and external fixation. METHODS: Patients with AO type C intra-articular distal radius fractures were randomized into 2 groups: open reduction and internal fixation and dorsal plating or external fixation and K-wires and mini-open reduction. Patients over the age of 70 years with any associated soft-tissue or skeletal injury to the same limb and pre-existing wrist arthrosis or disability were excluded from the study. Objective, subjective, and radiographic outcomes were assessed at 2 weeks, 4 to 6 weeks, 10 to 12 weeks, 6 months, and 1- and 2-year intervals. The minimum follow-up period was 6 months; the average follow-up period was 18 months. The principal outcome analyzed was the Disabilities of the Arm, Shoulder, and Hand score. Secondary outcomes included grip strength, range of motion, surgical procedure time, complications, and radiographic parameters. The groups were equal with respect to age, gender, fracture subtype, and number of workers' compensation cases. RESULTS: No significant difference was found in the Disabilities of the Arm, Shoulder, and Hand scores, our primary outcome. The dorsal plate group, however, showed a higher complication rate when compared with the external fixator group. The plate group had significantly longer tourniquet times when compared with the external fixator group. The plate group also had higher levels of pain at 1 year when compared with the external fixator group; however, this equalized after hardware removal. The external fixator group showed an average grip strength of 97% compared with the normal side and 86% in the dorsal plate group. CONCLUSIONS: At midterm analysis the dorsal plate group showed a significantly higher complication rate compared with the external fixator group; therefore enrollment in the study was terminated. The dorsal plate group also showed statistically significant higher levels of pain, weaker grip strength, and longer surgical and tourniquet times. Based on these results we cannot recommend the use of dorsal plates in treating complex intra-articular fractures of the distal radius.

Adult↗
PubMed1993

Comparative postoperative infection rates in midfacial trauma using intermaxillary fixation, wire fixation, and rigid internal fixation implants.

The use of rigid internal fixation implants in the repair of midfacial fractures requires more extensive bone exposure, soft-tissue manipulation, and operative time. We wished to determine the relative contribution of this method of repair to postoperative infection rates. Midfacial trauma cases occurring between the years 1984 and 1991 at the University of Iowa Hospitals and Clinics, Iowa City, were reviewed. Patients were grouped according to method of repair (intermaxillary fixation, open reduction with wire fixation, or open reduction with rigid internal fixation plates). Postoperative infection data (wound infections, sinusitis, etc) were obtained by chart review and telephone interview. Minimum follow-up for inclusion in the study was 3 months, with an average follow-up for all groups of 28.8 months. We found no significant difference in the rate, or the type, of postoperative infections in all three groups. We conclude that rigid internal fixation implants do not contribute increased postoperative infection rates in midfacial trauma.

Adult↗
PubMed2001

Ilizarov hybrid external fixation for fractures of the distal radius: Part II. Internal fixation versus Ilizarov hybrid external fixation: Stability as assessed by cadaveric simulated motion testing.

The in vitro stability of an Ilizarov hybrid external fixator was compared with that of a dorsal 3.5-mm AO T-plate in 8 unpaired, fresh-frozen upper extremities. A specially designed testing device that used computer-controlled pneumatic actuators was used to simulate active finger, wrist, and forearm motions by applying loads to relevant tendons. A comminuted extra-articular distal radius fracture was modelled using a dorsally based wedge osteotomy. Fracture stability was assessed using an electromagnetic tracking device to measure motion across the fracture site after randomized application of the plate and the hybrid fixator. During simulated finger and wrist motions with the forearm pronated or supinated, motion of the distal fragment with the hybrid fixator applied was comparable to or statistically less than with the AO plate applied. During simulated forearm rotation, the stability provided by the 2 fixation types was similar, although the plate allowed statistically less radial-ulnar deviation of the fragment. In this model of a 2-part extra-articular distal radius fracture, the clinically meaningful stability of the Ilizarov hybrid external fixator was comparable to that of the dorsal AO plate.

Aged↗
PubMed1983

Carbon Dioxide Fixation in Roots and Nodules of Alnus glutinosa: I. Role of Phosphoenolpyruvate Carboxylase and Carbamyl Phosphate Synthetase in Dark CO(2) Fixation, Citrulline Synthesis, and N(2) Fixation.

Detached roots and nodules of the N(2)-fixing species, Albus glutinosa (European black alder), actively assimilate CO(2). The maximum rates of dark CO(2) fixation observed for detached nodules and roots were 15 and 3 micromoles CO(2) fixed per gram dry weight per hour, respectively. The net incorporation of CO(2) in these tissues was catalyzed by phosphoenolpyruvate carboxylase which produces organic acids, some of which are used in the synthesis of the amino acids, aspartate, glutamate, and citrulline and by carbamyl phosphate synthetase. The latter accounts for approximately 30 to 40% of the CO(2) fixed and provides carbamyl phosphate for the synthesis of citrulline. Results of labeling studies suggest that there are multiple pools of malate present in nodules. The major pool is apparently metabolically inactive and of unknown function while the smaller pool is rapidly utilized in the synthesis of amino acids. Dark CO(2) fixation and N(2) fixation in nodules decreased after treatment of nodulated plants with nitrate while the percentage of the total (14)C incorporated into organic acids increased. Phosphoenolpyruvate carboxylase and carbamyl phosphate synthetase play key roles in the synthesis of amino acids including citrulline and in the metabolism of N(2)-fixing nodules and roots of alder.

Journal Article↗
PubMed1990

Fixation of mandibular fractures: a comparative analysis of rigid internal fixation and standard fixation techniques.

This study used a prospective design to compare standard therapy (closed or open reduction with 4 weeks of maxillomandibular fixation) to rigid internal fixation (RIF) for the treatment of mandibular fractures. Ninety-two patients with 143 fractures were evaluated and treated. There was no statistically significant difference in the treatment results between the two groups, despite a bias in the distribution of study variables that favored the standard therapy.

Adult↗
PubMed1998

Biomechanical evaluation of translaminar facet joint fixation. A comparative study of poly-L-lactide pins, screws, and pedicle fixation.

STUDY DESIGN: Nine sheep cadaveric spines were used in this acute postoperative model. OBJECTIVES: To compare the biomechanical performance of translaminar facet joint fixation techique with that of cortical screws and bioabsorbable poly-L-lactide pins and with that of rigid pedicle screw fixation in the lumbar spine. SUMMARY OF BACKGROUND DATA: Among numerous posterior spine fixation techniques, pedicle screw fixation has been reported to be the most rigid construct and to provide high fusion rate. Translaminar facet joint screw fixation is an alternative to pedicle screw fixation and is the lowest profile construct that achieves stabilization. The authors have developed a new concept involving application of bioabsorbable poly-L-lactide pins to translaminar facet joint fixation. Degradation in the stiffness of the implants with time may be advantageous for fusion mass remodeling. METHODS: A total of nine sheep L2-L6 cadaveric spines were used. Each intact spine was nondestructively tested in flexion-extension bending (+/- 5-Nm peak bending moment with 100-N axial compression) on a modified testing machine. Loads were applied for 10-second periods using sinusoid waveforms. After testing the intact spine, bilateral fenestration was performed between L4 and L5 and the medial aspect of the facet capsule was resected. The L4-L5 functional spinal unit was than stabilized by five methods: translaminar facet joint fixation with smooth poly-L-lactide pins; translaminar facet joint fixation with cortical screws; pedicle screw fixation with the Texas Scottish Rite Hospital system; and without instrumentation, in that order. Linear displacement of L4 inferior and L5 superior articular processes in the sagittal plain (delta facet) and L4-L5 intervertebral rotation in the sagittal plain (theta sagittal) were measured by the extensometers mounted to the spine. Ranges of motion (delta facet and theta sagittal), neutral zones, linear elastic zone stiffness, and the total energy absorption during the load-unload cycle (hysteresis) were calculated. RESULTS: By resecting the facet joint capsules and ligamentum flavum, delta facet and theta sagittal were not increased significantly, whereas the increase of neutral zones and hysteresis were statistically significant. Compared with the intact spine, delta facet was significantly reduced to 41% of normal with translaminar facet joint fixation with poly-L-lactide pins, to 9% with translaminar facet joint fixation with screws, and to 11% with the Texas Scottish Rite Hospital system. Neutral zones of delta facet showed a similar pattern, and these differences were significant. Regarding linear elastic zone stiffness, translaminar facet joint fixation with screws provided a stiffer construct than did pedicle screw fixation in the flexion loading mode, whereas pedicle screw fixation yielded higher values for stiffness in extension loading. Translaminar facet joint fixation with poly-L-lactide pins increased linear elastic zone stiffness in extension loading, but the increase was less than was achieved with the other constructs. CONCLUSIONS: The facet joint is the only true articulation in the lumbosacral spine. It is logical to fix this part directly to achieve spine fixation. Translaminar facet joint fixation with screws show similar biomechanical performance to pedicle screw fixation. Translaminar facet joint fixation with poly-L-lactide pins is significantly less stiff than either type of screw fixation, but it also restricts the facet joint and intervertebral motions significantly when compared with the intact spine.

Analysis of Variance↗
PubMed2006

Open reduction and internal fixation compared with circular fixator application for bicondylar tibial plateau fractures. Results of a multicenter, prospective, randomized clinical trial.

BACKGROUND: Standard open reduction and internal fixation techniques have been successful in restoring osseous alignment for bicondylar tibial plateau fractures; however, surgical morbidity, especially soft-tissue infection and wound necrosis, has been reported frequently. For this reason, several investigators have proposed minimally invasive methods of fracture reduction followed by circular external fixation as an alternative approach. To our knowledge, there has been no direct comparison of the two operative approaches. METHODS: We performed a multicenter, prospective, randomized clinical trial in which standard open reduction and internal fixation with medial and lateral plates was compared with percutaneous and/or limited open fixation and application of a circular fixator for displaced bicondylar tibial plateau fractures (Schatzker types V and VI and Orthopaedic Trauma Association types C1, C2, and C3). Eighty-three fractures in eighty-two patients were randomized to operative treatment (forty-three fractures were randomized to circular external fixation and forty to open reduction and internal fixation). Follow-up consisted of obtaining a history, physical examination, and radiographs; completion of the Hospital for Special Surgery (HSS) knee score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form-36 (SF-36) General Health Survey; and recording of complication and reoperation rates. RESULTS: There were no significant differences between the groups in terms of demographic variables, mechanism of injury, or fracture severity and/or displacement. However, patients in the circular fixator group had less intraoperative blood loss than those in the open reduction and internal fixation group (213 mL and 544 mL, respectively; p=0.006) and spent less time in the hospital (9.9 days and 23.4 days, respectively; p=0.024). The quality of osseous reduction was similar in the groups. There was a trend for patients in the circular fixator group to have superior early outcome in terms of HSS scores at six months (p=0.064) and the ability to return to preinjury activities at six months (p=0.031) and twelve months (p=0.024). These outcomes were not significantly different at two years. There was no difference in total arc of knee motion, and the WOMAC scores at two years after the injury were not significantly different between the groups with regard to the pain (p=0.923), stiffness (p=0.604), or function (p=0.827) categories. The SF-36 scores at two years after the injury were significantly decreased compared with the controls for both groups (p=0.001 for the circular fixator group and p=0.014 for the open reduction and internal fixation group), although there was less impairment in the circular fixator group in the bodily pain category (a score of 46) compared with the open reduction and internal fixation group (a score of 35) (p=0.041). Seven (18%) of the forty patients in the open reduction and internal fixation group had a deep infection. The number of unplanned repeat surgical interventions, and their severity, was greater in the open reduction and internal fixation group (thirty-seven procedures) compared with the circular fixator group (sixteen procedures) (p=0.001). CONCLUSIONS: Both techniques provide a satisfactory quality of fracture reduction. Because percutaneous reduction and application of a circular fixator results in a shorter hospital stay, a marginally faster return of function, and similar clinical outcomes and because the number and severity of complications is much higher with open reduction and internal fixation, we believe that circular external fixation is an attractive option for these difficult-to-treat fractures. Regardless of treatment method, patients with this injury have substantial residual limb-specific and general health deficits at two years of follow-up.

Adult↗
PubMed2000

Osteotomy, compression and reaming techniques for internal fixation of extracapsular hip fractures.

BACKGROUND: Many different surgical techniques, such as osteotomy, have been used in internal fixation of extracapsular hip fractures. OBJECTIVES: To compare different aspects of surgical technique in internal fixation of extracapsular hip fractures that have been subjected to randomised trials in adults. SEARCH STRATEGY: The Cochrane Musculoskeletal Injuries Group trials register, Medline, CENTRAL and reference lists of relevant articles were searched. Date of the most recent search: March 1999. SELECTION CRITERIA: All randomised and quasi-randomised trials investigating operative technique for the treatment of extracapsular hip fractures. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality, by use of an eleven item check list, and extracted data. Wherever possible and appropriate, results of outcome measures were pooled. MAIN RESULTS: All eight included trials were of only modest methodological quality. One trial of 65 patients undergoing fixation with a fixed nail-plate compared osteotomy versus anatomical reduction. There was a tendency to a reduced fixation failure rate after osteotomy. Four trials involving 465 patients undergoing fixation with a sliding hip screw (SHS) compared osteotomy versus anatomical reduction. Osteotomy was associated with an increased operative blood loss and length of surgery. There was also a tendency to an increased length of hospital stay and limb shortening for osteotomy. One trial of 200 patients undergoing fixation with a SHS compared results with or without compression across the fracture site. The only significant difference in outcomes was increased varus deformity in those fractures treated with compression. One trial of 19 patients reported reduced temperatures generated by a modified method of reaming the femoral head. Another study used oesophageal ultrasound to demonstrate reduced bone marrow intravascular embolism when a Gamma nail was inserted in 50 patients with, rather than without, a distal pressure venting hole in the femur. REVIEWER'S CONCLUSIONS: There is inadequate evidence to determine if any benefits exist for the routine use of osteotomy in conjunction with a SHS for the internal fixation of an unstable trochanteric femoral fracture. Osteotomy may be relevant if used in conjunction with a fixed nail plate. Based on the evidence of one trial only, there is inadequate evidence to support the application of compression across the fracture site of a trochanteric fracture during SHS fixation. Inadequate information exists for different reaming techniques during SHS or Gamma nail fixation to make definite conclusions.

Fracture Fixation, Internal↗
PubMed1997

Pulmonary effects of fixation of a fracture with a plate compared with intramedullary nailing. A canine model of fat embolism and fracture fixation.

UNLABELLED: Fat-embolism syndrome and pulmonary dysfunction may develop in multiply injured patients who have a fracture of a long bone. Although early fixation of a fracture is beneficial, intramedullary nailing may exacerbate pulmonary dysfunction by causing additional embolization of marrow fat. We examined the pulmonary effects of the timing and method of fixation of a fracture in a canine fat-embolism model. Fat embolism was induced in forty-one adult dogs by reaming the ipsilateral femur and tibia followed by pressurization of the intramedullary canal. The animals were divided into a control group of eight dogs that had induction of fat embolism alone and an experimental group of thirty-three dogs that had induction of fat embolism and internal fixation of a transverse fracture of the middle of the contralateral femoral shaft. In the control group, four dogs each were killed four hours and twenty-four hours after induction of fat embolism. In the experimental group, a femoral fracture was created and fixation was performed four hours after embolic showering in fifteen animals and twenty-four hours after embolization in eighteen animals. The two experimental groups were subdivided according to the method of fixation of the fracture: eleven dogs each had application of a plate, nailing without reaming, and nailing with reaming. The pulmonary arterial pressure and the alveolar-arterial gradient were measured preoperatively, during induction of fat embolism, and as long as one hour after fixation of the fracture but before the animal was killed. The lungs, brain, and kidneys were examined for pathological and physiological evidence of intravascular fat. The intravascular fat persisted for twenty-four hours after induction of pulmonary fat embolism. Pulmonary arterial pressure remained elevated at four hours after the embolic showering, before creation and fixation of the fracture. By twenty-four hours after the induction of fat embolism, pulmonary arterial pressure had returned to the baseline level. Neither the creation nor the fixation of the fracture affected pulmonary arterial pressure. In the animals that had fixation of a fracture four hours after embolization, both nailing with reaming and nailing without reaming produced alveolar-arterial gradients that were higher than the baseline values, whereas fixation with a plate did not change the alveolar-arterial gradient significantly from the baseline value. In addition, the alveolar-arterial gradients in the animals that had nailing with reaming and nailing without reaming four hours after embolization were, respectively, four and 3.5 times higher than that in the animals that had fixation of the femur with a plate. In the animals that had fixation twenty-four hours after embolization, none of the methods for fixation affected the alveolar-arterial gradient. The amount of embolic fat in the lungs, brain, and kidneys was not affected by fixation of the fracture when it was performed at either the four-hour or the twenty-four-hour time-interval. Scores for pulmonary edema were increased by fixation of the fracture, but there was no difference among the scores associated with the three methods of fixation. CLINICAL RELEVANCE: The findings of the present study indicated that the amount of intravascular fat persisting in the lungs, kidneys, and brain twenty-four hours after pressurization of the intramedullary canal is not affected by the method of fixation of the fracture. Fixation of a fracture is associated with minimum evidence of acute inflammation and has no effect on pulmonary artery pressure. The development of pulmonary dysfunction from fat emboli depends on other factors, not just on the presence of fat in pulmonary vessels. It appears that the method of fracture fixation has little influence on the outcome of treatment.

Animals↗
PubMedDate not supplied

Fixation methods for implantable port chamber: comparative study using glue, self-stabilizing leg and suture fixations in rabbits.

OBJECTIVE: To evaluate the fixation strength and tissue reaction of the glue fixation and self-stabilizing leg fixation methods and to compare the results with those of the conventional tagging suture fixation method. MATERIALS AND METHODS: Twelve healthy rabbits were selected and three different methods of implanting the port chamber were employed on the back of each rabbit. A total of thirty six port chambers were implanted with these three different methods, viz. the glue fixation method using tissue adhesive, the self-stabilizing leg method using a self-expandable stabilizing leg, and the suture fixation method. The fixation strength and the gross and histopathologic changes of each fixation method were evaluated at three days, one week, two weeks and four weeks after port implantation. RESULTS: The glue fixation method showed a good fixation strength, which was similar to that of the tagging suture method (p = 0.3486). Five of the six ports (83%) implanted with the glue fixation method which were examined after two weeks showed cracks on the external surface, but this had no adverse effects on their function. A large amount of granulation tissue reaction was found at the bottom of the chamber (p = 0.0025). The fixation with the self-stabilizing leg showed relatively lower fixation strength (p = 0.0043), but no turning-over of the chamber occurred. The fixation strength improved with time after the first week, and minimal granulation tissue reaction was observed with this method. CONCLUSION: The glue fixation method exhibited equal fixation strength compared to the suture fixation, but showed cracking and a large amount of granulation tissue, whereas the fixation with a self-stabilizing leg showed weaker fixation strength.

Alloys↗
PubMed2003

Mechanical performance of hybrid Ilizarov external fixator in comparison with Ilizarov circular external fixator.

OBJECTIVE: The aim of this study was to determine the stiffness characteristics of the standard and hybrid Ilizarov fixators. DESIGN: Five different frame models (one standard and four hybrid Ilizarov) were designed. Four full rings were used in the standard Ilizarov frame. Two rings were placed proximal and two rings were placed distal to the osteotomy line with two wires at 90 degrees to each other on each ring. The distal tibial fixation of all the hybrid configurations and standard Ilizarov fixator were the same, and only the proximal fixations were different. In hybrid models, different numbers of 90 degrees femoral arches (1-3) were fixed to the proximal segment by using the half-pins with different numbers (2-4) and different angles to each other (45 degrees and 90 degrees ). BACKGROUND: Numerous investigations have been performed to compare the mechanical properties of different frames. The Ilizarov method of fracture fixation and limb lengthening has recently gained international recognition. But its application is difficult in some anatomic localization, so that hybrid ring fixation frames of various configurations are gaining clinical popularity. METHODS: Five different frame models were applied to the sheep tibial bones. The midpoint of the tibial bones was osteotomised and the osteotomy distracted for 2 cm. Four identical samples for each model were created and each identical sample of each model (n=1) were tested four times in axial compression, antero-posterior and medio-lateral bending, and torsion. RESULTS: In standard Ilizarov fixator, axial and bending stiffness was found to be more than all hybrid Ilizarov fixator models. Between the hybrid fixators, higher axial and bending stiffness was found when the number of femoral arches and half-pins were increased. Different angles between the half-pins formed 67% alteration in medio-lateral bending stiffness. No significant difference was found for torsional stiffness between the fixator models. CONCLUSIONS: For optimum fixator stiffness in hybrid fixators, at least three femoral arches and four half-pins must be used and these half-pins should be placed at 90 degrees angles and at different planes to each other. However, it should be remembered that, hybrid fixator models had less axial and bending stiffness than standard Ilizarov fixator model. RELEVANCE: For optimum fixator stiffness in hybrid fixators, at least three femoral arches and four half-pins must be used. However, it should be remembered that, hybrid fixator models had less axial and bending stiffness than standard Ilizarov fixator model.

Animals↗
PubMed2006

Initial fixation strength of a hybrid technique for femoral ACL graft fixation.

Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screws provides a higher fixation strength when compared to an aperture fixation using only a screw matching the size of the tunnel and also reduces the risk of graft laceration. This research is an experimental laboratory study. We evaluated the initial fixation strength at time-zero of an extracortical-, a hybrid- and an aperture fixation in ACL reconstruction using extracortical buttons and different sized interference screws in porcine knees. The tests were performed using a single cycle and cyclic loading protocol. Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. Cyclic loading tests showed a statistically significant difference between hybrid and aperture fixation. The use of an undersized screw alone in aperture fixation resulted in insufficient fixation strength. The initial fixation strength of the hybrid technique with undersized screws is higher compared to an interference screw fixation alone. The hybrid fixation technique is an alternative for ACL graft fixation.

Absorbable Implants↗
PubMed2000

Biomechanical comparison of quadriceps tendon fixation with patellar tendon bone plug interference fixation in cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to use current fixation techniques and compare the stiffness and ultimate tensile failure of the tendinous end of the quadriceps tendon (QT) with the bone plug end of the bone-patellar tendon-bone (BPTB) graft using current techniques of fixation. TYPE OF STUDY: Randomized trial of elderly cadaver knees. MATERIALS AND METHODS: Tibial and femoral biodegradable interference fixation and femoral EndoButton (Smith & Nephew, Acufex, Mansfield, MA) fixation in bone tunnels with the QT and the BPTB graft were compared by using 10 pairs of elderly cadavers and biomechanical testing. Two groups, fixation at time zero (simulating fixation in the operating room) and testing after 1, 000 loading cycles (simulating patient rehabilitation exercises), were used. RESULTS: At time zero fixation, stiffness of the soft tissue QT tibial tunnel interference fixation was 59% less stiff than the stiffness of the interference fixation of a BPTB plug in a femoral tunnel (P =.11). The EndoButton femoral fixation resulted in a decrease in stiffness at time zero compared with femoral tunnel interference fixation of the soft tissue QT (P =.03). All groups improved stiffness with cycling the construct to 1,000 cycles. CONCLUSIONS: Placement of the QT tendinous end of the graft in the femoral bone tunnel when using a interference fixation will approximate the stiffness of a bone plug in the tibial bone tunnel with interference fixation. The EndoButton fixation is not as stiff as either of the femoral interference fixation options. The addition of more than 20 loading cycles could remove laxity from the graft fixation-graft cruciate ligament complex and improve its stiffness.

Anterior Cruciate Ligament↗