Periosteal Callus Formation Research Articles

New biological method of internal fixation of the femur

One of the main goals in fracture treatment is reservation of both intramedular and periosteal vascularisation. The aim of this paper is to show a new method of internal fixation which accomplishes these goals. The paper presents the results of clinical application of Mitkovic Internal Fixator, new self-dynamisable device, which provides fixation of the femur using minimally invasive technique. This device has been investigated experimentally on 60 animals. It has been applied to 267 patients. Here is presented a series of 92 fixations of femoral diaphyses after fresh fractures and after unsuccessful treatment using other methods. Follow-up was 3.1 years (2 to 7 years). Bone healing was achieved in all patients within 3.5 months (2.7-9 months) with big amount of periosteal callus formation. There were no complications in all patients seen. It can be concluded that this method and device meet biological and biomechanical requirements for safe fracture treatment.

The influence of cyclic compression and distraction on the healing of experimental tibial fractures

Interfragmentary displacement has a main effect on callus formation in fracture healing. To test whether compressive or distractive displacements have a more pronounced effect on new bone formation, a sheep osteotomy model was created whereby the gap tissue was subjected to constant bending displacement. A diaphyseal osteotomy with a gap of 2 mm was created in 18 sheep tibiae and stabilized with a special unilateral actuator-driven external fixator. Two experimental groups with six sheep each received either 10 or 1000 cycles evenly distributed over 24 h. The third group of six sheep served as a control group without actively induced displacement. The amount and direction of cyclic displacement was kept constant throughout the observation period, resulting in 50% compressive and 50% distractive displacement within the osteotomy gap. At sacrifice, six weeks after surgery, bending stiffness was measured and new bone formation was assessed radiologically and microradiographically. In all cycled groups, the amount of periosteal callus formation was up to 25 times greater on the compression compared to the distraction side ( p<0.001). The application of the higher number of daily cycles resulted in an up to 10-fold greater amount of periosteal new bone formation on the compression side ( p<0.012), while the difference on the distraction side was not significant. Ten cycles applied a day were sufficient to create an abundant periosteal callus on the compression side. In the 1000 cycle group, bending stiffness revealed slightly lower values but the difference was not significant. Solid periosteal bridging of the gap was observed in two sheep in the control group, whereas bridging in the cycled groups was observed exclusively at the medullary side. In conclusion, cyclic compressive displacements were found to be superior over distractive displacements. A higher number of enforced and maintained compressive displacements enhanced periosteal callus formation but did not allow bony bridging of the gap.

Gene expression of periostin in the early stage of fracture healing detected by cDNA microarray analysis

To comprehensively evaluate gene expression in the early stage of fracture healing, we used a cDNA microarray with 2304 cDNA clones derived from an oligo-capped mouse embryo library. Closed mid-diaphyseal fractures were created in mouse tibiae and expression profiles were analyzed 3 days after fracture. Six genes were up-regulated in comparison to those in unfractured bones and these included three genes previously identified but never shown to be present in fractures, periostin, calumenin, and FHL-1. Cloning of these genes has been completed but their expression pattern and function during fracture healing and bone formation remain to be elucidated. Up-regulation of the six genes was reconfirmed by semi-quantitative RT-PCR analysis. Spatial and temporal expression of one of the newly identified fracture-induced genes, periostin, was analyzed using in situ hybridization, because it displayed the highest up-regulation ratio. A signal for periostin was detected in undifferentiated mesenchymal cells and immature preosteoblastic cells in the periosteal tissues between days 3 and 14 after fracture. Northern analysis showed that periostin gene expression rapidly increased by day 3, reached a peak on day 7, and declined by day 14. These findings suggest that periostin is a specific marker for preosteoblasts and may play an important role in periosteal callus formation during the early stage of fracture healing.

Gene expression for extracellular matrix proteins in shockwave-induced osteogenesis in rats.

To clarify the mechanisms underlying shockwave-induced osteogenesis, we applied shockwave to rat femoral shafts from the ventral side. We assessed bone mineral content (BMC) and bone mineral density (BMD), and analyzed the spatial and temporal gene expression for pro-alpha1 (I) collagen (COL1A1), pro-alpha1 (II) collagen (COL2A1), pro-alpha1 (X) collagen (COL10A1), osteocalcin (OC) and osteopontin (OPN) using in situ hybridization. On the 21st day post-exposure, BMC and BMD in the exposed femur were elevated by 8.46% and 5.80%, respectively, relative to the unexposed femur. Immediately following exposure, there was evidence of scraping of the cortex and periosteal separation with hemorrhage. On day 4, new periosteal bone formation could be seen on the ventral and dorsal side of the femur. In the newly formed bone, COL1A1, OC and OPN were expressed in osteoblastic cells underlying the periosteum. On day 7, there was progression of periosteal bone and trabeculae formation. COL1A1 and OC were expressed in mature osteoblasts lining the trabeculae, whereas OPN was expressed in immature osteoblastic cells, osteocytes and osteoclasts. On day 14, bone remodeling commenced in the periosteal bone. COL1A1, OC and OPN were still expressed at this stage, however, signals were much weaker. Between 4-7 days, chondrocyte clusters were distributed multi-focally near the exposed site, and there was expression of COL2A1 but not of COL10A1. The results demonstrate that gene expression patterns of shockwave-induced osteogenesis are similar to those of periosteal hard callus formation during fracture healing. Shockwaves can yield dramatic activation of cells in normal long bones, and drive the cells to express genes for osteogenesis.

Microstructure and mineral content of femora in male turkeys with and without fractures

Microscopic and radiographic observations, as well as ash, calcium, phosphorus, copper, manganese, and zinc concentrations, were evaluated from femora of 32- to 35-wk-old male turkeys from two different farms (A and B). Turkeys from Farm A were divided into birds with femoral fracture (AF) and without femoral fracture (ANF). Turkeys from Farm B did not have femoral fractures (BNF). In the mid-diaphyseal cortex of turkeys without femoral fractures, collagen fibers were evenly distributed parallel to the transverse plane of bone surface. In contrast, collagen fibers were disorganized and the cortex was osteoporotic in turkeys with femoral fractures. Each turkey with femoral fractures also had callus on the mediocaudal region of the femoral middiaphysis. The periosteal callus was interrupted at the insertion of the puboischiofemoralis muscle. Muscle attachment to the bone might have interfered with the formation of periosteal callus. The concentration of calcium was lower in the cortex of turkeys in group AF compared to turkeys in groups ANF and BNF. The focal nature of the callus, along with the low levels of calcium, is indicative of a local repair response with alteration in cortical structure and altered concentrations of minerals in the cortex. These changes in the bone and the routine handling of the birds might have predisposed the turkeys to complete fractures of the femur.

Bilateral symmetrical cysts in the upper tibiae in a skeletally mature patient: might they be simple bone cysts?

A 55-year-old Japanese woman presented with right knee pain of 1-month duration. Radiological studies revealed bilateral mild osteoarthritic changes in the medial knee joint compartment and symmetrical cysts in the upper tibial metaphyses, extending to the epiphyses. Intraosseous ganglion was considered the most probable diagnosis. However, intraoperatively, serous fluid-filled cavities were recognized; these were curetted and filled with hydroxyapatite granules. Histopathological examination of the cyst wall revealed thin fibrous tissue formed of collagen fibers without a lining cell layer, with scattered lymphocytes, histiocytes, irregular masses of fibrin-like material, and periosteal osteocartilagenous callus formation; a picture compatible with simple bone cysts. Bilateral symmetrical cysts of the upper tibial metaphyses extending to the epiphyses are extremely rare. A literature review revealed that the age incidence, and bony locations of multiple and epiphyseal simple bone cysts are atypical in relation to the classic metaphyseal simple bone cysts. Also, multiple and epiphyseal simple bone cysts have a better prognosis than the classic metaphyseal ones. Four clinicoanatomic varieties of simple bone cysts are recognized; classic metaphyseal, nontubular, epiphyseal, and multiple.

Induction of periosteal callus formation by bone morphogenetic protein-2 employing adenovirus-mediated gene delivery.

Although the chondrogenic response of periosteum is well established in healing fractures, the mechanisms mediating the proliferation and differentiation of periosteal chondroprogenitor cells are poorly understood. In the present study we demonstrate that bone morphogenetic protein-2 (BMP-2), introduced by adenovirus-mediated gene transfer, alone is capable of inducing callus formation at the site of periosteal injection. Both immunohistochemistry and Northern analysis demonstrated activation of type II collagen production between days 4 and 7 after the injection, followed by activation of type X collagen expression. The activation of chondrogenesis was associated with increased expression of L-Sox5 and Sox9, suggesting that the BMP-2 effect is mediated via Sox proteins. This capacity of adenovirus-mediated overproduction of BMP-2 to induce chondrogenesis (and subsequent endochondral ossification) should be useful for tissue engineering of cartilage and bone.

Femoral Fractures in a Young Male Turkey Breeder Flock

Twenty-two 32-to-35-wk-old male turkeys from a commercial breeding flock were presented to the California Veterinary Diagnostic Laboratory System, Fresno Branch, with a clinical complaint of lameness and increased mortality. Necropsy findings included a unilateral, closed oblique fracture involving the femur in 12 birds. Ten complete femoral fractures had periosteal new bone adjacent to and bridging the fracture. Periosteal callus formation, in this case, suggested that preexisting lesions preceded complete fracture of the femur. Factors such as selection for heavy body weight, lack of exercise, and handling might have contributed to the development and promotion of complete fractures.

Influence of size and stability of the osteotomy gap on the success of fracture healing.

Flexible fixation of fractures with minimally invasive surgical techniques has become increasingly popular. Such techniques can lead to relatively large fracture gaps (larger than 5 mm) and considerable interfragmentary movements (0.2-5 mm). We investigated the influence of the size of the fracture gap, interfragmentary movement, and interfragmentary strain on the quality of fracture healing. A simple diaphyseal long-bone fracture was modeled by means of a transverse osteotomy of the right metatarsus in sheep. In 42 sheep, the metatarsus was stabilized with a custom-made external ring fixator that was adjustable for gap size and axial interfragmentary movement. The sheep were randomly divided into six groups with three different gap sizes (1, 2, or 6 mm) and small or large interfragmentary strain (approximately 7 or 31%). The movement of the fracture gap was monitored telemetrically by a displacement transducer attached to the fixator. After 9 weeks of healing, the explanted metatarsus was evaluated mechanically in a three-point bending test to determine bending stiffness and was radiographed to measure the amount of periosteal callus formation. Increased size of the gap (from 1 to 6 mm) resulted in a significant reduction in the bending stiffness of the healed bones. Larger interfragmentary movements and strains (31 compared with 7%) stimulated larger callus formation for small gaps (1-2 mm) but not for larger gaps (approximately 6 mm). The treatment of simple diaphyseal fractures with flexible fixation can be improved by careful reduction of the fracture; this prevents large interfragmentary gaps. The experimental fracture model for the metatarsus showed that the healing process was inferior when the gap was larger than 2 mm.

Stress fractures in skeletally immature patients.

Stress fractures are a common injury in an active population. As children become increasingly involved in organized sports, the recognition of stress fractures and differentiation from infections or neoplasms requires a knowledge of their most common sites, presentation, and clinical course. We retrospectively reviewed 34 stress fractures in 32 skeletally immature patients from June 1977 to May 1993. Age, fracture location, treatment, time to union or healing, associated conditions, complications, radiographs, and clinical outcome were recorded. Fifty percent of patients were involved in sports; the most common complaint was pain with activity. The most common site was the tibia (47%) followed by the fibula (21%) and femur (12%). All had resolution of symptoms and returned to normal activity. All but two healed with either activity modification or cast immobilization. The radiographic findings included early periosteal callus formation that rapidly consolidated to new bone on serial studies. A careful history, physical examination, and radiographs can help diagnose most common stress fractures in the skeletally immature individual and can differentiate stress fractures from infection or neoplasm with appropriate conservative treatment.

Early, Full Weightbearing With Flexible Fixation Delays Fracture Healing

Secondary fracture healing is known to be accelerated by the process of periosteal callus formation that can be induced by flexible fracture fixation in connection with loading of the injured extremity. The purpose of this study was to compare the healing of experimental fractures of long bones in sheep under early weightbearing with that of fractures under delayed, steadily increasing weightbearing. Differences in the quality of fracture healing were described by biomechanical (rigidity of fracture, indentation stiffness of callus) and histologic methods. Prevention from early, full weightbearing resulted in a higher flexural rigidity of the fracture, an increased mechanical stiffness of the callus tissue, and an enhanced bone formation at the healing front. Although early loading of a fresh fracture initiated an enormous amount of periosteal callus, the healing of the osteotomy was significantly delayed, and the quality of the newly formed tissue was reduced as compared with fractures with a reduced loading situation. A reduction of load transfer by delaying full weightbearing is advantageous for the healing of fractures stabilized with flexible fixation systems.

The Fate of Free, Pedicled and Free Vascularized Cancellous Iliac Bone Grafts and the Effect on the Healing of Femoral Osteotomy: An Experimental Study

A new model for vascularized and nonvascularized iliac bone autograft transfer to a femoral shaft osteotomy site is presented in this experimental study. As demonstrated on roentgenograms taken at 4 to 6 weeks postoperatively, callus formation between vascularized grafts and recipient sites was 1.5 to 2 times faster than in the nonvascularized graft transfer. According to densitometric analysis, conventional free grafts lost more hydroxyapatite and restored their mineral structure at a slower rate than vascularized grafts. There was no difference between free vascularized and pedicled grafts in the rate of mineral deposition changes, but the pedicle grafts had more significant loss of bone density. Formation and mineralization of periosteal callus between the femoral-shaft fragments took place more rapidly in the first 12 weeks after pedicled bone transplantation. The correlation between the densitometric results and morphologic behavior of transplanted bones was examined. It was demonstrated that all of the grafts at the recipient site underwent remodeling into cortical bone. However, vascularized, and especially pedicled, grafts maintained their cancellous structure relatively longer.

Distraction Osteogenesis A Comparison of Corticotomy Techniques

The left hindlimbs of 15 adult mongrel dogs were lengthened using the Ilizarov external fixator. Five dogs were assigned to each of three separate groups: (I) corticotomy; (II) osteotomy with multiple drill holes and an osteotome; (III) osteotomy with an oscillating saw. Distraction began on postoperative day seven and continued at a rate of 0.25 mm every six hours for 26 days. The regenerate segments were evaluated with weekly radiographs and Dual Energy Photon X-ray (DEPX) beginning at day seven. Barium perfusion studies and histologic preparations were also performed after the dogs were killed. Periosteal callus formation was apparent in all groups at two weeks, and endosteal callus appeared in Groups I and II at three to four weeks. Perfusion studies at the end of the distraction period demonstrated vessels bridging across the regenerate gap in Groups I and II. Vessels bridging the gap were diminished in the oscillating-saw Group III specimens. During the distraction period, the appearance and length of the regenerate bone was similar for each group radiographically and by DEPX scanning. No histologic differences were seen in Groups I and II. Three of the four tibias cut with the oscillating saw did not consolidate at ten weeks. A simple transverse osteotomy yields regenerate bone that is indistinguishable from the technically more difficult corticotomy. Use of the oscillating saw may lead to delayed consolidation.

Clinical evaluation of uniaxially oriented poly-L-lactide rod for fixation of experimental femoral diaphyseal fracture in immature cats.

Transverse diaphyseal fractures of the femur were experimentally made in immature cats, and were fixed by an intramedullary pinning technique using an uniaxially oriented poly-L-lactide (PLLA) rod, a biodegradable polymer. The healing process was evaluated radiographically and histologically. Formation of bony callus was completed in 8 weeks, and cortical bony union followed. The remodeling process was then observed form 12 to 16 weeks. The healing process was almost the same as when a metallic implant was used. Abundant periosteal callus formation may be attributable to the lower elasticity of the PLLA rod compared with metallic implants. Since no other abnormalities such as growth deformities were detected, it was concluded that the combined use of a uniaxially oriented PLLA rod and an external splint is clinically useful for the repair of diaphyseal fractures in immature cats.

Bone-Healing Patterns Affected by Loading, Fracture Fragment Stability, Fracture Type, and Fracture Site Compression

The major factors determining the mechanical milieu of a healing fracture are the rigidity of the selected fixation device, the fracture configuration, the accuracy of fracture reduction, and the amount and type of stresses occurring at the bone ends dictated by functional activity and loading at the fracture gap. Of the effects of these factors on fracture healing and remodeling in the canine tibia under unilateral external fixation, the two most significant factors in promoting periosteal callus formation were the amount of physiologic loading as dictated by the body weight and the presence of a significant fracture gap. Uniform axial loading and motion, performed at two or four weeks, did not increase callus formation but did reduce the existing fracture gap. The time-related diminution of periosteal callus (external remodeling) was related to the progress of cortical healing. Cortical reconstruction was fast in stable transverse fractures and delayed in unstable oblique fractures. Motion with loading tended to promote external callus maturation in secondary bone healing. Intracortical new bone formation and porosity were related to the healing pattern and not to the loading magnitude. Endosteal new bone formation showed a strong correlation with the presence of a fracture gap. In terms of torsional strength and energy absorption at failure, the fractures healing through a combination of primary and secondary bone union mechanisms showed the mechanical strength of the healing bone closest to intact bone.

Canine Osteotomy Healing when Stabilized with Decreasingly Rigid Fixation Compared to Constantly Rigid Fixation

SummaryThis study investigated the effect of destabilizing initially rigid external fixation of transverse canine tibial osteotomies, compared to contralateral osteotomies continuously stabilized, with rigid fixators. Destabilization, by conversion of a type III configuration fixator to a type I configuration, after one to four weeks resulted in increased periosteal callus formation but decreased mechanical strength and histologically a preponderance of fibrous and cartilaginous tissues in the osteotomy when studied after nine weeks. Destabilization at six weeks did not result in an increase in periosteal callus formation, nor greater bending strength. Histologically there was a combination of woven and lamellar bone, with the appearance of more active remodelling of primary bone healing. Destabilization at 12 weeks did not result in any effect, when studied after 15 weeks. These findings suggest that increasing weight-bearing loading of a fracture, at the proper time, may enhance the remodelling and hypertrophy of primary bone healing. However, inappropriate timing of destabilization may not have any or even a deleterious effect.Effects of reducing initially rigid fixation of canine tibial osteotomies, after various periods of time, were studied. Destabilization after one to four weeks caused increased periosteal callus formation but decreased mechanical strength. Destabilization after six weeks resulted in increased mechanical strength but no increase in periosteal callus, and destabilization after 12 weeks had no effect compared to osteotomies continuously stabilized with rigid fixation.

Newest Factors in Fracture Healing

Natural selection has evolved a process of fracture healing that is characterized by callus formation and is enhanced by physical loading and motion at the fracture site. Internal fixation of fractures alters the biology of fracture healing, especially when rigid fixation using plates is performed. Intramedullary nails that allow some motion and loading usually are associated with callus formation. Plates that practically eliminate interfragmentary motion, however, prevent external periosteal callus formation. Primary osteonal healing can occur with plate fixation, but if interfragmental gaping of greater than 1 mm exists, delayed healing occurs. Closed treatment of fractures occasionally results in nonunion. In addition, physicians' high expectations for skeletal restoration have prompted vigorous research in areas of bone grafting, graft substitutes, and analysis of local and systemic factors that regulate fracture healing. A better understanding of the activity of bone morphogenetic protein and growth factors, such as transforming growth factor beta, will allow manipulation of the biology of healing to enhance the surgical treatment of skeletal trauma.

Bone physiology and metabolism in dental implantology: risk factors for osteoporosis and other metabolic bone diseases.

Placing a dental implant elicits a time-dependent bone response controlled by wound-healing factors (cytokines, bioelectrical signals), biomechanics (gravitational, functional, and therapeutic loads), and mineral metabolism (hormones, diet, excretion). The osseous response to an implant involves four physiological stages: (1) endosteal and periosteal callus formation; (2) compaction and remodeling of the callus; (3) remodeling (turnover) of the nonvital interface and adjacent bone; and (4) maturation (secondary mineralization) of new bone. Long-term maintenance of a rigid implant interface is related to continual bone remodeling. Common metabolic bone disorders affecting potential implant patients are osteopenia ("osteoporosis"), renal osteodystrophy, osteomalacia, and Paget's disease. The most prevalent problem is a long-term negative calcium balance leading to a compromise in bone strength. Symptomatic osteoporosis (usually wrist, hip, and/or spine fractures) affects 4 to 50 percent of the population depending on age, race, sex, endocrine status, and life-style. Postmenopausal white and Asian females present the greatest risk. The jaws of "osteoporotic" adults are variably affected because of the moderating influence of mechanical function. Management of metabolic bone disorders is an important consideration in diagnosis, treatment planning, and long-term monitoring of dental implants. Bone metabolic counseling, a natural extension of preventative dentistry, is an unexpected benefit readily appreciated by patients and their families.

A developmental model for free vascularized bone transfers in the dog.

An autogenous free vascular bone transfer using a segment of ulna along with its periosteum and vascular pedicle was developed. The vascular pedicle, based on the common interosseous artery and vein, emerged where muscular branches from the cranial interosseous artery enter the extensor carpi ulnaris and lateral digital extensor muscles. Four autogenous heterotopic (ulna to tibia) vascular transfers by microvascular anastomosis and two avascular transfers were performed to compare the osteogenic potential and viability of free revascularized grafts with avascular bone grafts. Successful microvascular anastomosis was demonstrated in three of the four vascular transfers by early bone scanning using technetium-labeled polyphosphate. Radiographically, there was more periosteal new bone and callus formation in the successfully revascularized bone transfers than in the failed vascular transfer and the avascular controls. Histologically, viable bone with an intact medullary and periosteal vascular supply was recognized in the grafts successfully revascularized by microvascular anastomosis.

Effects of periosteal activation agent on bone repair and ingrowth.

A substance that activates the resting periosteum (PAA) was applied to the periosteal surface in two different healing models using the femurs of 2-kg male rabbits. The activation agent was applied to the periosteal surface over the sites of circular defects drilled through the lateral cortex in one model and over the sites of porous polyethylene implants placed in the lateral cortex and the medullary canal in the other model. Results failed to show that the agent either enhanced bone ingrowth into the porous implants or accelerated bony filling of the circular defects. However, there was indication of enhanced mineralization and periosteal callus formation as early as 24 h after application.