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At least 109 records · Page 6Linked to original sources
PubMed1999

The merit of sintered PDLLA/TCP composites in management of bone fracture internal fixation.

Polyesters based on lactic acid have been reported in terms of safety and biodegradation in human beings for 2 decades. The greatest advantage of such material is its degradation conducted only by hydrolysis, whereby the ester backbones are supposed to be unchained in the aqueous condition. The final degradable products are carbon dioxide and water which can be metabolized and digested in the physiological environment. The goal of this study was aimed at developing a composite sintered with poly-DL-lactide (PDLLA) and tricalcium phosphate (TCP) ceramic particles for orthopedic application. The TCP particles in a range of 30-60 wt% with 5 wt% increments were doped into the PDLLA matrix which was prepared by melting and hot pressing techniques for the reinforcement. The basic mechanical strength, biodegradable behavior, and biological response of the composites were investigated in the study. Various techniques such as pH meter, UV, Fourier-transform infrared, and x-ray diffractometer were used to examine and record the degradable process of the composites soaked in saline for 1-16 weeks. The rabbit femur condyle fracture fixation test was used to evaluate tissue compatibility and the effects of bone fracture fixation on the composites. Histological observation and x-ray photography were used for investigating assistance. The mechanical strength of the composites initially increased with TCP additions up to 50wt%, but thereafter they showed no significant difference (p < 0.05). The composite with 50 wt% TCP addition showed greater mechanical strength and had good agreement with cortical bone in terms of its elastic modulus of 30-40 GPa. The weight loss of the pure PDLLA soaked in the saline started at 4 weeks and reached 95% after 16 weeks. The composites compared with pure PDLLA, however, showed no apparent evidence of degradation after soaked for 12 weeks. The possible mechanisms for the delayed degradation of the composites in saline might have been solution penetration retardation by the ceramic particles and chemical bonds formed between the interface of the TCP particles and the PDLLA matrix. In the histological evaluation of the rabbit femur condyle fracture fixation test, the surface of the composite with 50 wt% TCP addition was attached by the newly generated bone without fibrous tissue around 8 weeks after implantation. The fractured bone was gradually healed and the composite firmly and properly fixed on the fracture area during the implanted period, which provided a breeding environment for normal bone remodeling. The developed composite was thought to be an alternative material for orthopedic application in the future, especially for bone screws and bone plates.

Absorption↗
PubMedDate not supplied

Treatment of tibial plateau fractures with small fragment internal fixation: a preliminary report.

OBJECTIVE: To evaluate the use of small fragment implants for fractures of the proximal tibia. DESIGN: Retrospective. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Seventeen patients with AO Classification Type B and C fractures of the proximal tibia. Two patients were lost to follow-up. INTERVENTION: After atraumatic dissection and open reduction, fracture stabilization was accomplished with the use of the AO/ASIF small T-plate (3.5-millimeter system). In two patients a medial uniplanar external fixator was applied as additional fixation. In six patients a cancellous autograft was performed. MAIN OUTCOME MEASUREMENTS: At an average follow-up of forty-two months (range, 24 to 75 months), all patients were evaluated radiographically and functionally. The incidence of local complications was specifically recorded. RESULTS: Postoperatively, the radiographs showed 86.7 percent anatomic or near anatomic reduction with respect to the articular joint surface. In three separate patients condylar widening, condylar narrowing or varus deformity was evident. In one patient, a minimal secondary displacement of less than two millimeters was observed before bony healing. All fractures healed within twelve weeks. At the latest follow-up, there were 53.3 percent excellent, 33.3 percent good, and 13.3 percent fair results. There were no infection or soft tissue complications. CONCLUSIONS: The use of small fragment implants combined with atraumatic soft tissue dissection potentially offers good results for the treatment of fractures of the proximal tibia. These initial results suggest that this technique may have the advantage of anatomic reduction while comparing favorably with less invasive methods regarding radiologic and functional outcome as well as incidence of complications.

Adolescent↗
PubMedDate not supplied

Biomechanical evaluation of the less invasive stabilization system for the internal fixation of distal femur fractures.

OBJECTIVE: Comparison between a Less Invasive Stabilization System (LISS) using monocortical screws with angular stability and two conventional plate systems Condylar Buttress Plate (CBP) and Dynamic Condylar Screw (DCS) for the treatment of distal femoral fractures with respect to biomechanical properties. DESIGN: Biomechanical study using paired cadaver femurs. In Test Configuration 1 (distal test), a ten-millimeter gap at the diaphysis-metaphysis junction simulates a supracondylar femoral fracture. Test Configuration 2 (proximal test) has the same configuration, but the gap was cut in the isthmic region. Proximal and distal plate ends were fixed to corresponding cortical bone fragments in both tests. Optical displacement transducers served to quantify the system's ability to withstand a stepwise increased load. Reversible (deflection) and irreversible deformation (subsidence) of the bone-plate construct was investigated. RESULTS: In Test Configuration 1, LISS showed less irreversible deformation in 72 percent of the left-right comparisons. No correlation between bone mineral density, cross-section area of bones and the measured response of the construct under load was found between pairs. In Test Configuration 2, 83 percent of the left-right comparisons showed less permanent deformation but a higher elastic deformation for LISS. CONCLUSIONS: These results suggest an enhanced ability to withstand high loads when using the monocortical screw fixation technique with angular stability. A higher elastic deformation of LISS compared with conventional plating systems in distal femoral fractures can be explained by the lower bending stiffness caused by different design and material properties.

Biomechanical Phenomena↗
PubMed1997

Internal fixation in the osteoporotic spine.

The presence of osteoporosis in patients who are candidates for spinal surgery can affect preoperative planning. These patients may not need instrumentation for a successful surgical result, but if use of instrumentation is indicated because of instability or deformity, certain principles should be observed. These include using multiple sites of fixation, accepting lesser degrees of deformity correction, and avoiding ending the instrumentation within kyphotic segments. Advances in perioperative medical management, as well as improved instrumentation systems, may also contribute to improving patient outcomes.

Adult↗
PubMedDate not supplied

Internal fixation with biodegradable rods in pediatric fractures: one-year follow-up of fifty patients.

Fifty children with transphyseal or osteochondral fractures were treated with biodegradable osteosynthesis material and followed for at least 1 year. All 50 fractures healed, and there were no major complications; 11 of them were fractures of the radial humeral condyle. In a prospective randomized study, they were compared with metal pin fixation of the same fracture (eight cases). No major differences were noted. After the study was completed, we observed two cases of nonunion of intraarticular fractures of the radial head, probably related to foreign body reaction to the resorbable implant material. Biodegradable osteosynthesis material is advantageous in treatment of children's fractures because it makes a removal operation unnecessary. It is ideal in cases of osteochondral fractures. Further experience with this material is necessary, however, before it can be safely recommended.

Adolescent↗
PubMed1998

Choice of implant for internal fixation of femoral neck fractures. Meta-analysis of 25 randomised trials including 4,925 patients.

We reviewed all randomised trials comparing different implants for treating intracapsular fractures of the hip and, where possible, the data were combined. 25 randomised trials were identified involving 4,925 patients. Screws appeared to be superior to pins. It was not possible to determine the optimum number or type of screws. No advantage was shown for an implant with a side-plate.

Bone Nails↗
PubMed1992

Internal fixation of ulnar fractures by locking nail.

Fractures and dislocations of the forearm are commonly observed in trauma clinics. With time, there will probably be significant increases in fractures of the forearm associated with traffic and sports. The efficacy of the treatment of ulnar fractures by a new locking nail, developed by Lefevre in Strasbourg, was tested in 20 patients. The fractures were severely displaced ulnae or both bones of the forearm. The minimum follow-up period was six months. The average age of the patients was 33.5 years (range, 14-77 years). The nail is placed into the ulna proximally. Locking is achieved by two screws placed at the proximal and distal end of the nail. The healing time for the fractures of both bones of the forearm ranged from 75 days to 20 weeks, with an average of 15 weeks. Healing time for the ulnar fractures ranged from eight to 20 weeks, with an average of ten weeks. The advantages of this nail were easy closed technique, compression effects at the fracture site, and enough stability so that an external support and tourniquet, in isolated ulnar fractures, were not necessary.

Adolescent↗
PubMed2004

From unstable internal fixation to biological osteosynthesis. A historical overview of operative fracture treatment.

The first techniques of operative fracture treatment were developed in the 19th century. In fact, these methods only consisted of an open reduction of the fracture followed by a usually very unstable fixation. This method gave rise to the combination of the disadvantages of the conservative and the operative fracture treatment: the fracture had to be opened with a real risk for (sometimes lethal) infection, the bone healing was disturbed, there was muscular atrophy and joint stiffness. The successes were very rare and catastrophes were often seen. Küntscher's endomedullary rods can be considered as the first useful implants in the treatment of diaphyseal fractures. Reaming of the medullary canal and the development of interlocking nails have enlarged the indications for intramedullary nailing. The classic Dynamic Compression Plates from the seventies were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates and reamed nails disturbed the vascularisation of the bone fragments, leading to a high infection rate (particularly in open fractures) and delayed union (particularly after plate and screw fixation). These insights lead to the development of the "biological osteosynthesis" : a terminology introduced to indicate a new type of osteosynthesis leading to a sufficiently stable fixation of the bone fragments allowing early mobilisation, but without major disturbance of the vascularisation. The unreamed nail can also be considered as a biological osteosynthesis and in a lot of cases it is the implant of choice for tibial and femoral shaft fractures, especially in polytrauma patients. Finally, some new devices contributing to the principles of biological osteosynthesis like locking plates and the LIS-System are gaining popularity.

Bone Nails↗
PubMed1993

[Morphological study of the microcirculation in regional cortical bones affected by internal fixation plates].

In order to elucidate the potential role of bone microcirculation in the development of plate-induced regional osteoporosis, microangiography was used to observe the morphological changes of microcirculation in cortical bones obtained from intact rabbit tibiae on which plates of two different stiffness had been fixed for comparison. The results indicated that both rigid stainless steel plates and less rigid methyl methacrylate plates could induce the bone microcirculation under and opposite the plate to undergo a changing process from early depression to later reactive recruitment. The features of the microcirculation recruitment as shown in vascular number, arrangement and dilatation varied with different stiffness plates and in different locations, and might also have bearing on the formation of osteoporosis.

Animals↗
PubMed2007

The use of rigid internal fixation in the surgical management of cervical spondylosis.

In the surgical management of cervical spondylosis, the application of rigid internal fixation can enhance the immediate stability of the cervical spine. The sophistication of such internal fixation systems and the indications for their use are continuously evolving. A sound understanding of regional anatomy, biomechanics, and kinematics within the cervical spine is essential for the safe and effective application of internal fixation. Numerous options currently exist for anterior cervical plating systems; some lock the screws to the plate rigidly (constrained), whereas others allow for some rotational or translational motion between the screw and plate (semiconstrained). The role of anterior fixation in single and multilevel fusions is still the subject of some controversy. Long anterior cervical reconstructions may require additional posterior fixation to reliably promote fusion. Rigid fixation in the posterior cervical spine can be achieved with lateral mass screws or pedicle screws. Although lateral mass screws provide excellent fixation within the subaxial cervical spine, the regional anatomy of C2 and C7 often make it difficult to place such screws, and pedicle screws at these levels are advocated. Pedicle screws achieve fixation into both the anterior and posterior column and are arguably the most stable form of rigid internal fixation within the cervical spine. Familiarity with these internal fixation techniques can be an extremely valuable tool for the spine surgeon managing these degenerative disorders of the cervical spine.

Cervical Vertebrae↗
PubMed1995

Free flap reconstructions of tibial fractures complicated after internal fixation.

The cases of 15 patients are presented where microvascular soft-tissue reconstructions became necessary after internal fixation of tibial fractures. Primarily, seven of the fractures were closed. Eleven fractures had originally been treated by open reduction and internal fixation using plates and screws, and four by intramedullary nailing. All of the patients suffered from postoperative complications leading to exposure of the bone or fixation material. The internal fixation material was removed and radical revision of dead and infected tissue was carried out in all cases. Soft tissue reconstruction was performed using a free microvascular muscle flap (11 latissimus dorsi, three rectus abdominis, and one gracilis). In eight cases the nonunion of the fracture indicated external fixation. The microvascular reconstruction was successful in all 15 patients. In one case the recurrence of deep infection finally indicated a below-knee amputation. In another case, chronic infection with fistulation recurred postoperatively. After a mean follow-up of 26 months the soft tissue coverage was good in all the remaining 13 cases. All the fractures united. Microvascular free muscle flap reconstruction of the leg is regarded as a reliable method for salvaging legs with large soft-tissue defects or defects in the distal leg. If after internal fixation of the tibial fracture the osteosynthesis material or fracture is exposed, reconstruction of the soft-tissue can successfully be performed by free flap transfer. By radical revision, external fixation, bone grafting, and a free flap the healing of the fracture can be achieved.

Adult↗
PubMed1998

"Biological" internal fixation of long bone fractures: a biomechanical study of a "noncontact" plate system.

Based on existing knowledge of noncontact plates, an experimental prototype of a nonperiosteal contact internal fixation implant ("noncontact internal fixator") has been designed. The construct rigidity of osteotomised synthetic composite femora, fixed with the noncontact fixator and a reamed, statically-locked intramedullary nail were compared in axial compression, two plane bending and torsion in four types of diaphyseal fractures. With the exception of axial loading in the presence of extensive comminution, the fixation stability provided by the noncontact fixator is significantly higher than that of the tested intramedullary nail. Any degree of cortical contact between the two main fragments is important for the stability of this nonperiosteal contact fixation system under axial load. Appropriately-designed "internal fixators" could provide not only a number of biological and technical advantages, but also fixation stability comparable and in certain aspects superior to that of other fixation methods.

Biomechanical Phenomena↗
PubMed1991

Posterior internal fixation with screw plates in traumatic lesions of the cervical spine.

Posterior internal fixation associated with bone fusion is indicated in those traumatic cervical spines in which an additional posterior direct action is required to achieve reduction and/or decompression. The internal fixation device is represented by screw plates allowing strong anchorage, short fixation, and light postoperative immobilization. Twenty-three cases of posterior internal fixation in traumatic cervical spines are presented. In selected cases, the results can be estimated as very good with respect to instability, spinal balance involvement, canal stenosis, and reversible neurologic involvement.

Adult↗