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Surgical repair of skull fractures in four horses using cuttable bone plates.

Three horses with severely comminuted, open facial bone fractures and one horse with a comminuted, open orbital rim fracture were referred for treatment. Severe facial bone asymmetry and epistaxis were apparent in all cases and subcutaneous emphysema was present in two, however physical and neurological examinations were otherwise normal. Radiography and endoscopy were of some use in assessing the degree of damage, although the true extent of the damage was more apparent at surgery. Surgical reduction of the fractures was recommended to maximise cosmetic and functional outcome. After surgical debridement and reduction of the fractures the bone fragments remained unstable and were not amenable to stabilisation with interfragmentary wires alone, so 2 mm cuttable bone plates were used to maintain fracture alignment. Screw migration occurred in three horses and in one of these horses the plate had to be removed. Other complications were minor and in all horses the fractures healed with good cosmetic and functional outcome. The use of cuttable bone plates should be considered as a reasonable alternative to inter-fragmentary wiring for unstable, comminuted fractures of the facial bones, even where fractures are open.

Animals↗

Healing of fractures with freeze-dried cortical bone plates. Comparison with compression plating.

The healing of fractures of the radius with internal fixation by stainless-steel compression plates was compared with fractures fixed with freeze-dried bone-plate allografts. Fractures fixed with metallic plates gained slightly less than half the biomechanical strength of the contralateral control bone and healed without noticeable external callus formation. Bone-plated fractures regained three-fourths of the biomechanical strength of controls and healed by forming an external callus. Bone-plate allografts were eventually incorporated in the host bone. Allograft plates were vascularized and remodeled into cancellous bone in the process of incorporation in the host bones.

Animals↗

Buccal bone plate thickness of the Asian people.

Distances from the apex to the buccal bone plate were measured on the computed tomography (CT) images of 1806 teeth from 66 patients, using an image analyzer program (Image-Pro Plus, Ver. 4.0, Media Cybernetics). In the mandible, the mean distance from the distal apex of the mandibular second molar to the buccal bone plate was the largest distance measured, at 8.51 mm, followed by distance from the mesial root to the buccal bone (7.34 mm). In the mandibular first molar, the mean distal and mesial bone thicknesses were 5.18 mm and 4.09 mm, respectively. However, when there were two distal roots, the distance of the disto-lingual root to the buccal plate was found to be 9.52 mm, which constitutes the greatest measured thickness. In the maxillary buccal roots, the distances from the mesio-buccal and disto-buccal root of the second molar to the buccal bone plate were the largest, at 4.63 mm and 3.61 mm, respectively. The average distances from the palatal apex of the maxillary first and second molars to the buccal bone plate were 10.69 mm and 10.17 mm, respectively, while, from the palatal bone plate, average distances of 3.15 mm and 3.08 mm were measured. Special considerations, such as bony lid approach, lingual approach, or intentional replantation may be required, especially when a patient has a surgical need in the second molars and the disto-lingual root of the mandibular first molar, or in the palatal root of the maxillary molars.

Adolescent↗

The mandibular staple bone plate: a long-term retrospective evaluation.

PURPOSE: Clinical and radiographic parameters and denture satisfaction were evaluated in a long-term retrospective study of patients treated with the mandibular staple bone plate. PATIENTS AND METHODS: Fifty-six edentulous patients were treated with the mandibular staple bone plate to stabilize their lower denture. The mean evaluation period was 103 months (range, 84 to 139 months). Peri-implant mucosa and bone height were scored, together with quality of the prosthesis and prosthodontic maintenance care. Denture satisfaction was assessed by using two questionnaires. RESULTS: Four staple bone plates were removed during the evaluation period, and one appeared to be fractured. The remaining 51 staple bone plates were functional without any signs of major complications (survival rate, 91%). No further alveolar resorption in the interforaminal region of the mandible took place during the evaluation period. Patients were very satisfied with the prosthetic construction. CONCLUSIONS: The mandibular staple bone plate is a good modality to stabilize the lower denture. However, endosseous implant systems are preferred because of comparable success rates with a more simple operative procedure.

Adult↗

[Reconstruction of periprosthetic fractures of hip with cortical bone plates allografts].

OBJECTIVE: To observe clinical results for reconstruction of periprosthetic fractures of hip with cortical bone plates allografts by deep-freezing and ethylene oxide treatment. METHODS: Seven patients with periprosthetic fractures of hip underwent cortical bone plates allografts by deep-freezing at -70 degrees C after being treatment of 48 degrees C ethylene oxide. And evaluate clinical outcome by examining T lymphocytes, Harris scores, X-rays photograph, and bone scintigraphy. RESULTS: There were not activity of immune rejection and infection in all patients. Harris scores of patients increased 21, 32, 40, 40 scores at 3, 6, 12, 24 months after surgery. T-lymphocytes, antibody and immunocomplex in blood was normal postoperation. X-ray film indicated that fracture was healed at 3 months and there was partially bone conjunction between allograft strut and host bone. There was incorporation of 85% allograft strut to host bone, and 15% allograft strut was partially absorbed at 12 months after surgery. The size of femur of host was added 3 mm to 5 mm, averaged 4.3 mm at 12 months postoperation. Density of 80% allograft plates was as same as host bone after remodeling and the absorbtion of 10% allograft plates stopped at 24 months after surgery. There was thick of nuclein in the area of allograft cortical bone plates by bone scintigraphy examination at 3 months postoperation, and the thick of nuclein was stronger at 6, and 12 months after surgery. CONCLUSION: Allograft cortical bone plates by deep frozen at -70 degrees C after being treatment of 48 degrees C ethylene oxide is suitable for mechanical fixation and biological bone transplantation, and it can increase bone reservation, augment strength of femur once the allograft strut incorporates to host bone, and avoid removing metal implant in second operation when being applied into reconstruction femoral fracture in joint replacement.

Aged↗

PLGA bone plates reinforced with crosslinked PPF.

In this study a matrix of poly(propylene fumarate) (PPF) was crosslinked with N-vinylpyrrolidone (NVP), 2-hydroxyethylmethacrylate (HEMA), or a mixture of NVP and ethyleneglycol dimethacrylate (EGDMA) in the presence of poly(lactide-co-glycolide) (PLGA) to reinforce and preserve the form of PLGA bone plates. The degree of crosslinkage varied depending on the crosslinker as shown by the rapid and almost complete leaching of NVP upon incubation in phosphate buffered saline at 37 degrees C in 900 h and retention of 92% of HEMA. With the reinforced bone plates extracted for 72 h at room temperature methylene chloride, the extracted PLGA from NVP/PPF, NVP-EGDMA/PPF, and HEMA/PPF were 75.42% (w/w), 59.52% (w/w), and 30.86% (w/w), respectively. The flexural modulus and compressive strength of the crosslinked PPF reinforced bone plates were higher than that of the unreinforced bone plate. Atomic force microscopy showed that NVP/PPF reinforced PLGA bone plates eroded substantially (a mean surface roughness of 19.319 nm) whereas NVP-EGDMA-PPF reinforced bone plate showed a distinct crystalline organization (and a higher roughness, 43.525 nm). In conclusion, we propose the consideration of NVP-EGDMA/PPF reinforced PLGA as a biodegradable orthopedic implant material that has a lower likelihood of warping or failing catastrophically than the currently available materials.

Journal Article↗

The three-dimensional mandibular bone plate.

A new type of mandibular bone plate implant has been described that immobilizes the mandible more ridigly than do previous bone appliances. Because of this characteristic, maxillomandibular fixation may be eliminated in a large percentage of fractured mandibles, or the time for immobilization is, at least, reduced.

Bone Plates↗

Healing of bone defects by an osteopromotion technique using solvent-dehydrated cortical bone plate: a clinical and radiological study.

Osseous defects of the jaws following trauma, cysts, infection or congenital deformity may show poor osteogenesis and the affected area may never be completely filled with bone. It is widely accepted in guided tissue regeneration that physically halting soft connective tissue proliferation into bone allows bone regeneration. This concept is called the "osteopromotion principle." The purpose of the present study was to evaluate the effect of solvent-dehydrated cortical bone plates as a barrier to allow bone regeneration by assessing the osteopromotion principle. 30 patients (18 male, 12 female) with cystic lesions of the jaws were assigned to two different groups. The patients in Group A were treated by enucleation. In Group B, were treated by removal of the lesion and placing a solvent-dehydrated cortical bone plate on top of the cyst cavity to avoid ingrowth of connective tissue. Both groups were evaluated radiographically using spiral-computed tomography (CT) before surgery and 12 months postoperatively. In group B, all cystic cavities showed complete bone healing in 12 months. At the same period, invasion of the soft connective tissue were observed in the patients treated only by enuclation. This study demonstrates that solvent-dehydrated cortical bone plates can be used as a barrier in treatment of cyst cavities and they hinder ingrowth of connective tissues and promote successful bone healing.

Adolescent↗

The use of self-reinforced biodegradable bone plates and screws in orthognathic surgery.

PURPOSE: This report describes the authors' experience with self-reinforced biodegradable bone plates and screws to stabilize maxillary and mandibular osteotomies. Patient acceptance, demographics, types of osteotomy, means of stabilization, etiology of the deformity, complications, and patient disposition are reviewed. PATIENTS AND METHODS: Seventy patients underwent 194 osteotomies of the maxilla and/or mandible. Stabilization of each osteotomy was achieved using self-reinforced polylactite bone plates and/or screws of similar size and configuration to that of titanium systems. Placement of the devices was accomplished transorally and transfacially, consistent with the osteotomy approach. Maxillomandibular elastics were used to control the position of the jaws in each patient. RESULTS: There was good patient acceptance of the material (70/74). Stabilization was accomplished as planned in all patients. Three patients experienced problems that resulted in immediate loosening of the bone screws. The remaining 67 experienced no short-term problems (6 to 24 months), and healing progressed uneventfully. In each case, acceptable occlusion and favorable aesthetic changes were noted. CONCLUSIONS: The experience with self-reinforced polylactite bone plates and screws to stabilize maxillary and mandibular osteotomies has been favorable on short-term observation.

Absorbable Implants↗

Buckling of adaptive elastic bone-plate: theoretical and numerical investigation.

During day-to-day activities, many bones in the axial and appendicular skeleton are subjected to repetitive, cyclic loading that often results directly in an increased risk of bone fracture. In clinical orthopedics, trabecular fatigue fractures are observed as compressive stress fractures in the proximal femur, vertebrae, calcaneus and tibia, that are often preceded by buckling and bending of microstructural elements (Müller et al. in J Biomechanics 31:150 1998; Gibson in J Biomechanics 18:317-328 1985; Gibson and Ashby in Cellular solids 1997; Lotz et al. in Osteoporos Int 5:252-261 1995; Carter and Hayes in Science 194:1174-1176 1976). However, the relative importance of bone density and architecture in the etiology of these fractures are poorly understood and consequently not investigated from a biomechanical point of view. In the present contribution, an attempt is made to formulate a bone-plate buckling theory using Cowin's concepts of adaptive elasticity (Cowin and Hegedus in J Elast 6:313-325 1976; Hegedus and Cowin J Elast 6:337-352 1976). In particular, the buckling problem of a Kirchhoff-Love bone plate is investigated numerically by using the finite difference method and an iterative solving approach (Chen in Comput Methods Appl Mech Eng 167:91-99 1998; Hildebland in Introduction to numerical analysis 1974; Richtmyer and Morton in Difference methods for initial-value problems 1967).

Biomechanical Phenomena↗

Mechanical and material properties of the subchondral bone plate from the femoral head of patients with osteoarthritis or osteoporosis.

OBJECTIVE: To determine the material properties of the subchondral bone plate in patients with osteoarthritis or osteoporosis. METHODS: Femoral heads were obtained after surgical removal from age and sex matched groups of patients with either osteoporosis (OP), after a fractured neck of femur, or osteoarthritis (OA) and compared with a normal group. The mechanical stiffness, density, and composition of the subchondral bone plate from sites selected to represent areas of heavy, intermittent, and light loading were measured. RESULTS: Overall, OP bone was the least stiff and dense, followed by OA bone; normal bone was stiffer and more dense (p < 0.05). Though OP bone contained less mineral, the organic and water contents were increased in proportion suggesting no change in the relative amount of organic matrix. OA bone was also hypomineralised (p < 0.05) but had different organic and water fractions suggesting a defect in the matrix. Site variation of most properties was small, though across all the groups the superior region was significantly stiffer than the inferior. CONCLUSION: This study shows that subchondral bone plate is less stiff than normal in both OP and OA and so cannot, by itself, explain the preserving of the overlying cartilage in OP while aiding its destruction in OA. However, the subchondral bone plate is only one part of the bony structure of the femoral head and changes in the cancellous bone need to be considered. The generalised changes in bone composition found in patients with OA support the hypothesis that the disease could involve the bone in the primary pathogenesis.

Aged↗

Performance study of braided carbon/PEEK composite compression bone plates.

In addition to unidirectional laminates and short fiber reinforcements for compression bone plate developments in the literature, we have proposed using a textile structure, i.e. braid preform, for this purpose. In the present paper, the influence of braiding angles and plate thicknesses on the bending performance of the braided composite bone plates is investigated. As a result, the influence of the braiding angle, varied in a certain range, on the plate bending properties is not significant when the plate thickness is thin. This influence becomes higher with an increase in the plate thickness. A 10 degrees braiding angle has been seen to be appropriate for all the cases under consideration. The present study indicates that the braided composite plate with 2.6mm thickness can be suitable for forearm treatment whereas the braided composite plate of 3.2mm thickness is applicable to femur or tibia fixation.

Animals↗

Environmental effects on the life of bone-plate-type surgical implants.

Assuming satisfactory fixation of metallic bone-plates and no subsequent accidental high impact loading, the major cause of implant failure during the lifetime of the patient will be that of corrosion fatigue. The mechanisms of corrosion fatigue are various and component life depends on a large number of interacting variables. These variables are noted and the particular importance of changing pH in a saline environment for implants is discussed. It is known, for example, that very low pH of body fluids results from shock and/or locally in the crevice between implant and bone. Some in vitro test results for stainless steel type 316, titanium 130, and titanium alloy 318, at a "walking pace" of 1.7 Hz, simulating normal and extreme conditions possibly met in practice, are reported. Further, since it is commonplace for some bone-plates to be drilled for fitting, the combined effect of this procedure and a changing local environment has been investigated. The life of stainless steel 316 was not affected by the hole drilling, but its use as an implant material is questionable because of poor resistance to corrosion fatigues at "lower-than-normal" pH. A small reduction in the life of titanium 130 resulted from the hole drilling operation. However, this material was generally superior to stainless steel at low pH. Titanium 318 showed by far the best resistance to corrosion fatigue but its performance was drastically reduced by hole drilling. Some early failures were also noted as the result of fretting with T318. Good implant design, and cautious modifications when fitting, is required here for the realization of the full potential of T318.

Alloys↗

The design and analysis of a laminated partially degradable composite bone plate for fracture fixation.

During the early stages of fracture healing, rigid internal fixation maintains alignment and promotes primary osseous union. Unfortunately, as healing progresses rigid fixation from bone plating can cause bone in the region of the plate to undergo stress protection atrophy. This can result in significant loss of bone mass and osteoporosis. Refracture of the bone upon device removal is a widely reported complication. In an effort to minimize or eliminate stress protection atrophy, we have designed a partially absorbable, fiber-reinforced bone plate. Ideally, such a plate gradually loses rigidity as the fracture heals, increasingly transferring stress to the bone. Stress protection may be avoided and removal of the device after healing may be unnecessary. Composite theory was used to determine an optimum fiber layup for a composite bone plate. Composite analysis suggested the mechanical superiority of a 0 degree/ +/ -45 degree laminae layup. Given this laminated design, a thermoplastic absorbable polymer (polylactic acid polymer) was reinforced with high-modulus carbon fiber to produce a semiabsorbable composite. Implant evaluation included optimizing fabrication techniques, thorough mechanical device testing, and implantation on canine femurs to determine biocompatibility and efficacy. The composite design proved to have superior static and fatigue properties to laminated or random fiber designs used previously. Two techniques for hole fabrication were tested. The production of screw holes during the molding process rather than machining postmolding, improved the mechanical integrity of the finished plate. Although the 0 degree/ +/- 45 degree carbon/polylactic acid composite possessed superior mechanical properties, it was unsuccessful in the in vivo environment. Water absorption and subsequent delamination made the plate flexible. Hypertrophic nonunions developed. Further development to prevent water intrusion and premature loss of mechanical properties is necessary.

Absorption↗

Postsurgical maxillary movement: a comparison study of bone plate and screw versus wire osseous fixation.

This study was designed to examine amounts of postoperative maxillary movement in patients who received Lefort I osteotomies, comparing bone plate and screw fixation with conventional transosseous wire fixation. Cephalograms of 17 patients whose maxillae were fixated with wire osseous fixation and 13 patients whose maxillae were fixed with bone plates and screws were compared at four different time periods throughout the first postoperative year. Millimeters of movement of five maxillary assessment points were assessed in the horizontal and vertical planes of space by use of a line constructed 7 degrees to sella-nasion at nasion as the horizontal reference. Results indicate that the amount of maxillary movement was similar for the two groups during the two time periods subsequent to the surgical procedure. However, it appears that the maxillae fixated with bone plates and screws were more stable than those with wire osteosynthesis during the last postoperative period (6 months to 1 year) and during the overall postoperative time interval (2 days to 1 year).

Adult↗

[Use of cortical bone plates allografts for reconstruction of femoral fracture: an experimental study in goats].

OBJECTIVE: To study the outcome of reconstructing goat femoral fracture by use of cortical bone plates allografts that have been kept by deep-freezing at -70 degrees C for 4 weeks after being treated with 48 degrees C ethylene oxide. METHODS: The recipients, sixteen 10-12-month-old goats with fractures of right femur were subjected the operation for transplanting the cortical bone plates allografts in the medial, lateral and back sides of fractured femurs. The goats were sacrificed and the specimens were procured at 3, 6, 12, and 24 weeks after surgery for X-ray photography, Chinese ink perfusion, tetracycline fluorescence labeling and histological observation in order evaluate the healing of fracture and the incorporation of cortical bone plates allografts. RESULTS: The allograft strut was found revascularized at 6 weeks after surgery in the fracture group, whereas at 3 weeks in the control group. The tetracycline fluorescence labeling was poor in the fracture group as compared with that in the control group from 3 weeks to 6 weeks, but it was better in the fracture group than in the control group beyond 6 weeks after surgery. Fracture was healed and bone conjunction between allograft strut and host bone was seen at weeks after operation. The allograft strut was incorporated in host bone, the ability of remodeling of allograft strut and the size of femoral cortex were better in the fracture group than in the control group at 24 weeks after surgery. The fracture was displaced in 19% animals and the allograft bone plates were not fractured. CONCLUSION: The use of allograft strut pre-treated by ethylene oxide sterilization and deep-freezing could underpin fixation and promote healing of femoral fracture, and it can increase bone reservation and augment the strength of femur once the allograft strut is incorporated in the host bone.

Animals↗

Pantarsal arthrodesis with a customised medial or lateral bone plate in 13 dogs.

Pantarsal arthrodesis was performed in 12 dogs using a customised medial bone plate, and in one using a lateral bone plate. The dogs' ages ranged from 14 months to 144 months (median 30 months) and their bodyweights ranged from 7 to 66 kg (median 32 kg). Before the surgery they had been lame on a pelvic limb for between one and 16 months (median eight months). In eight of the dogs the fixation of the plate was augmented with a calcaneotibial positional screw, and in one of them with a talocrural lag screw. A cranial half cast was applied to 12 of the dogs and an external skeletal fixator to the other for six to eight weeks. Five complications were recorded in four of the dogs. Between 29 and 156 weeks postoperatively the clinical outcome was graded as excellent in six dogs, good in six dogs and fair in the other.

Animals↗

Salvage of humeral nonunions with onlay bone plate allograft augmentation.

Eight women and one man were treated for 10 established diaphyseal humeral nonunions. Six patients sustained fractures in motor vehicle accidents and two patients sustained fractures in a fall. Two of the fractures were open. One patient with multiple myeloma originally was treated conservatively and received local radiation, followed by open reduction and internal plate fixation. The other patients previously were treated with fracture braces, intramedullary nails, dynamic compression plates, or a combination of these techniques. After removal of the surgical hardware and fibrous tissue at the nonunion site, stable fixation was accomplished using a cortical long bone plate allograft (femoral and tibial) or fibular shaft allograft and a dynamic compression plate. All humeral nonunions had united at an average of 2.9 months. Radiographic incorporation of the allograft cortical bone plate and fibular shaft into the host cortex occurred in all but one patient by 3 months. Graft to host junction healing was accomplished by incorporation of the cortical allograft plate into the host cortex, resulting in an increased diameter of the bone. Cortical allograft bone plates and fibular grafts provide structural and probably osteoinductive support to enhance healing of these nonunions.

Adult↗