医用磷酸钙在特发性脊柱侧凸矫形融合术中的应用

[目的]比较医用磷酸钙和自体髂骨在特发性脊柱侧凸矫形融合术中的临床效果.[方法]回顾性分析2006年6月～2009年1月在本科行钉-棒内固定系统矫形手术的62例特发性脊柱侧凸患者,其中自体髂骨移植组28例,医用磷酸钙移植组34例.对两组患者的平均手术时间、出血量、并发症、融合率、矫形丢失进行对比分析.[结果]62例患者均获得随访,每组至少随访24个月.两组患者出血量、手术时间相比,差异有统计学意义(P＜0.05).在自体髂骨组中,有2例(7.1％)出现感染,1例(3.6％)出现躯干不平衡,3例(10.7％)患者在最后一次随访中供区疼痛仍未消失.在磷酸钙组中,有2例(5.8％)出现术后切口渗出,1例(2.9％)出现感染.在移植术后第9个月,自体髂骨组融合率高于磷酸钙组(P＜0.05),其他时间相比两组融合率无统计学意义(P＞0.05).在术后最终随访中,主弯Cobb角度矫形丢失两组差异无统计学意义(P＞0.05).[结论]医用磷酸钙应用于特发性脊柱侧凸患者的后路融合术中可以达到满意的临床效果,避免了取髂骨移植带来的相应并发症.     

Effects of hydroxyapatite tricalcium phosphate coating and intracancellous placement on bone ingrowth in titanium fibermetal implants

The purpose of this study was to compare the host—bone response to hydroxyapatite/tricalcium phosphate (HA/TCP)-coated and noncoated titanium fibermetal implants placed in a load-sharing cancellous bone environment of the distal femurs of rabbits. The influence of implantation site was also investigated by comparing these intracancellous implants with intramedullary implants evaluated in a previous study. Three parameters were measured: percentage implant perimeter surface length in contact with new bone, percentage internal fibermetal surface length in contact with ingrown bone, and percentage of available pore space filled with bone. The HA/TCP coating significantly accelerated and increased bone ongrowth, new bone formation on the perimeter and internal surface of the implants. This effect was evident as early as 2 weeks after implantation. In contrast, there was no difference between HA/TCP-coated and noncoated implants in the bone ingrowth parameter, percentage of available pore space filled with bone, or pull-out strength. Scanning electron microscopy in the backscatter mode demonstrated that new bone formed directly onto the HA/TCP-coated fibers and did not usually form directly on noncoated fibers. Analysis of fluorochrome labeling revealed that bone formation in weeks 1 through 4 was primarily woven and there-after lamellar. Compared with intramedullary placement, intracancellous placement significantly accelerated the apposition of bone to the perimeter and internal surface of HA/TCP-coated implants and both accelerated and increased bone ingrowth as a percentage of available pore volume. These data show that the host response to titanium fibermetal implants is influenced both by HA/TCP coating and by the implantation site.     

Release of gentamicin from a tricalcium phosphate bone implant.

The impregnation and elution of gentamicin antibiotic from a commercially available porous beta-tricalcium phosphate (TCP) bone implant material (Vitoss, Orthovita, Inc.) was investigated in vitro. Sustained local antibiotic release is an attractive method for the prevention of infection following surgery. The purpose of this study was to evaluate the use of the naturally forming clot that occurs within a porous tissue scaffold when combined with autologous blood or bone marrow aspirate (BMA) as a method for achieving controlled drug delivery. The diffusion of antibiotic from porous TCP scaffolds was studied using water, clotted blood, or BMA as impregnating fluids. Incorporation of the drug into the porous scaffold using clotted blood or BMA as a binder produced slowed release relative to aqueous impregnated and dried samples. Modifications were made to the elution method to simulate restricted diffusion due to surrounding clotted blood, tissue, or bone that would occur in vivo. These modified methods simulated release in a surgical site and showed long release profiles, with significant amounts of antibiotic being released for up to 2 weeks. We concluded that adding gentamicin with autologous BMA is a promising method of controlling drug release.     

Submicron‐surface structured tricalcium phosphate ceramic enhances the bone regeneration in canine spine environment

Calcium phosphate ceramics with submicron‐scaled surface structure can trigger bone formation in non‐osseous sites and are expected to enhance bone formation in spine environment. In this study, two tricalcium phosphate ceramics having either a submicron‐scaled surface structure (TCP‐S) or a micron‐scaled one (TCP‐B) were prepared and characterized regarding their physicochemical properties. Granules (size 1–2 mm) of both materials were implanted on either left or right side of spinous process, between the two lumbar vertebrae (L3‐L4), and in paraspinal muscle of eight beagles. After 12 weeks of implantation, ectopic bone was observed in muscle in TCP‐S explants (7.7 ± 3.7%), confirming their ability to inductively form bone in non‐osseous sites. In contrast, TCP‐B implants did not lead to bone formation in muscle. Abundant bone (34.1 ± 6.6%) was formed within TCP‐S implants beside the two spinous processes, while limited bone (5.1 ± 4.5%) was seen in TCP‐B. Furthermore, the material resorption of TCP‐S was more pronounced than that of TCP‐B in both the muscle and spine environments. The results herein indicate that the submicron‐scaled surface structured tricalcium phosphate ceramic could enhance bone regeneration as compared to the micron‐scaled one in spine environment. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1865–1873, 2016.     

多孔载因子CPC促进骨缺损愈合的实验研究

[目的]探讨磷酸钙骨水泥复合rhBMP-2/明胶微球复合材料在治疗骨缺损时的降解、成骨性能。[方法]制备携载rhBMP-2的明胶微球(GMs),与磷酸钙骨水泥(CPC)复合,制备出rhBMP-2/GMs/CPC复合人工骨。取30只新西兰大白兔,在前臂桡骨中段制造人工骨缺损,随机分成3组,分别植入rhBMP-2/GMs/CPC/复合物(A组)、GMs/CPC(B组)、rhBMP-2/CPC(C组),术后6、12周分别进行X线检测、骨密度测定,术后12周处死动物,分别行生物力学测定,脱钙切片、HE染色,不脱钙切片进行荧光显微镜下观察双标间距,计算平均矿化率。[结果]与GMs/CPC、rhBMP-2/CPC组比较,复合材料植入后不同时间点的材料降解及成骨均高于对照组。12周A组标本生物力学实验测定结果表明指标接近正常,与B、C组比较有统计学差异。骨密度12周、新骨矿化率提示有统计学差异。[结论]rhBMP-2/GMs/CPC微球系统复合材料在体内易降解,具有良好成骨活性,是良好的骨修复材料。     

Platelet‐rich plasma on calcium phosphate granules promotes metaphyseal bone healing in mini‐pigs

The role of platelet‐rich plasma (PRP) as a promoter of bone healing remains controversial. The aim of this study was to investigate the effect of PRP in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect. A metaphyseal bone defect at the proximal tibia of 16 mini‐pigs was filled with CPG combined with autologous PRP or CPG solely (control group). The PRP showed 4.4‐fold more platelets compared to peripheral blood. Six weeks after surgery the radiological and histomorphometrical evaluations showed significantly more bone formation in the PRP group in the central area of the defect zone (p < 0.01) as well as the cortical defect zone (p < 0.04). Furthermore, the resorption rate of CPG was increased in animals who received PRP. Nevertheless there were only isolated instances of complete osseous bridging of the bone defects even in the PRP group. This study demonstrates that a PRP‐CPG composit promotes bone regeneration but does not lead to a solid fusion of a tibial defect in mini‐pigs. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1448–1455, 2010     

Selective laser melting‐produced porous titanium scaffolds regenerate bone in critical size cortical bone defects

Porous titanium scaffolds have good mechanical properties that make them an interesting bone substitute material for large bone defects. These scaffolds can be produced with selective laser melting, which has the advantage of tailoring the structure's architecture. Reducing the strut size reduces the stiffness of the structure and may have a positive effect on bone formation. Two scaffolds with struts of 120‐µm (titanium‐120) or 230‐µm (titanium‐230) were studied in a load‐bearing critical femoral bone defect in rats. The defect was stabilized with an internal plate and treated with titanium‐120, titanium‐230, or left empty. In vivo micro‐CT scans at 4, 8, and 12 weeks showed more bone in the defects treated with scaffolds. Finally, 18.4 ± 7.1 mm³ (titanium‐120, p = 0.015) and 18.7 ± 8.0 mm³ (titanium‐230, p = 0.012) of bone was formed in those defects, significantly more than in the empty defects (5.8 ± 5.1 mm³). Bending tests on the excised femurs after 12 weeks showed that the fusion strength reached 62% (titanium‐120) and 45% (titanium‐230) of the intact contralateral femurs, but there was no significant difference between the two scaffolds. This study showed that in addition to adequate mechanical support, porous titanium scaffolds facilitate bone formation, which results in high mechanical integrity of the treated large bone defects. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 792–799, 2013     

An injectable composite material containing bone morphogenetic protein‐2 shortens the period of distraction osteogenesis in vivo

To investigate new methods that can decrease the duration of bone transport (BT) distraction osteogenesis, we injected composite materials containing recombinant human bone morphogenetic protein‐2 (BMP‐2) and induced the generation of a callus bridge by rapid segmental transport (4 mm/day) in a rabbit bone defect model. The composite materials consisted of BMP‐2 (0, 30, or 100 µg), β‐tricalcium phosphate powder (βTCP, 100 mg/animal; particle size, <100 µm), and polyethylene glycol (PEG; 40 mg/animal). A paste of equivalent composition was percutaneously injected at the lengthening and the docking sites after surgery and after BT, respectively. The radiographic, mechanical, and histological examinations 12 weeks post‐operative revealed that the generation of bridging callus in the presence and in the absence of BMP‐2 was significantly different. The callus mass in the bone defect region was adequately and consistently developed in the presence of 100 µg of BMP (administered for 6 weeks), and the bones were consolidated in 12 weeks. Such an adequate callus formation was not observed in the control animals without BMP‐2 treatment. The result of this experimental study suggests the potential application of BMP‐2 in accelerating callus formation and in enabling rapid bone transporting, thereby shortening the treatment period for the repair of diaphyseal bone defects by distraction osteogenesis. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:452–456, 2011     

Effects of chronic estrogen treatment on modulating age‐related bone loss in female mice

While female mice do not have the equivalent of a menopause, they do undergo reproductive senescence. Thus, to dissociate the effects of aging versus estrogen deficiency on age‐related bone loss, we sham‐operated, ovariectomized, or ovariectomized and estrogen‐replaced female C57/BL6 mice at 6 months of age and followed them to age 18 to 22 months. Lumbar spines and femurs were excised for analysis, and bone marrow hematopoietic lineage negative (lin–) cells (enriched for osteoprogenitor cells) were isolated for gene expression studies. Six‐month‐old intact control mice were euthanized to define baseline parameters. Compared with young mice, aged/sham‐operated mice had a 42% reduction in lumbar spine bone volume/total volume (BV/TV), and maintaining constant estrogen levels over life in ovariectomized/estrogen‐treated mice did not prevent age‐related trabecular bone loss at this site. By contrast, lifelong estrogen treatment of ovariectomized mice completely prevented the age‐related reduction in cortical volumetric bone mineral density (vBMD) and thickness at the tibial diaphysis present in the aged/sham‐operated mice. As compared with cells from young mice, lin– cells from aged/sham‐operated mice expressed significantly higher mRNA levels for osteoblast differentiation and proliferation marker genes. These data thus demonstrate that, in mice, age‐related loss of cortical bone in the appendicular skeleton, but not loss of trabecular bone in the spine, can be prevented by maintaining constant estrogen levels over life. The observed increase in osteoblastic differentiation and proliferation marker gene expression in progenitor bone marrow cells from aged versus young mice may represent a compensatory mechanism in response to ongoing bone loss. © 2010 American Society for Bone and Mineral Research.     

大段仿生活性人工骨修复兔长骨缺损的实验研究

目的观察以聚左旋乳酸、磷酸三钙、重组人骨形态发生蛋白-2(rhBMP-2)制备的大段仿生活性人工骨对骨缺损的修复效果。方法利用快速成形技术制备多孔状的聚左旋乳酸-磷酸三钙大段人工骨载体材料,负压复合rhBMP-2后制备成大段仿生活性人工骨。将36只新西兰大白兔随机等分为三组,手术造成右前臂桡骨中上段15mm骨缺损。实验组植入15mm仿生活性人工骨,对照组a为材料对照,对照组b为空白对照。通过影像学、组织学、骨密度检查及图像分析技术观察骨缺损的修复效果及材料的降解情况。结果①影像学结果表明,实验组术后12周新生骨痂将缺损修复,修复率100%,术后24周骨痂塑形良好。两对照组术后24周内均无骨痂形成,缺损未修复。②组织学显示:实验组术后12周骨痂外层为皮质骨,中央为含有骨岛的载体材料,术后24周骨痂皮质骨与材料之间形成贯通的髓腔;材料对照组术后12周缺损区为纤维组织包裹的载体材料,空白对照组形成纤维连接。③实验组术后12、24周的骨密度值分别为正常值的70.6%和96.8%。④术后12周实验组和材料对照组的降解率分别是38.3%和31.4%,术后24周分别为54.2%和43.4%。结论以聚左旋乳酸、磷酸三钙和rhBMP-2制备的大段仿生活性人工骨对骨缺损具有良好的修复作用。     

Recombinant human platelet‐derived growth factor BB (rhPDGF‐BB) and beta‐tricalcium phosphate/collagen matrix enhance fracture healing in a diabetic rat model

Diabetes mellitus is a common systemic disease that has been associated with poor fracture healing outcomes. The mechanism through which diabetes impairs bone regeneration is unknown. One possible mechanism may be related to either decreased or uncoordinated release of local growth factors at the fracture site. Indeed, previous studies have found reduced platelet‐derived growth factor (PDGF) levels in the fracture callus of diabetic rats, suggesting that local application of PDGF may overcome the negative effects of diabetes and promote fracture healing. To test this hypothesis, low (22 µg) and high (75 ug) doses of recombinant human PDGF‐BB (rhPDGF‐BB) were applied directly to femur fracture sites in BB Wistar diabetic rats that were then compared to untreated or vehicle‐treated animals. rhPDGF‐BB treatment significantly increased early callus cell proliferation compared to that in control specimens. Low dose rhPDGF‐BB treatment significantly increased callus peak torque values (p < 0.05) at 8 weeks after fracture as compared to controls. High dose rhPDGF‐BB treatment increased callus bone area at 12 weeks postfracture. These data indicate that rhPDGF‐BB treatment ameliorates the effects of diabetes on fracture healing by promoting early cellular proliferation that ultimately leads to more bone formation. Local application of rhPDGF‐BB may be a new therapeutic approach to treat diabetes‐impaired fracture healing. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 1074–1081, 2009     

Promotion of osteogenesis in tissue‐engineered bone by pre‐seeding endothelial progenitor cells‐derived endothelial cells

In addition to a biocompatible scaffold and an osteogenic cell population, tissue‐engineered bone requires an appropriate vascular bed to overcome the obstacle of nutrient and oxygen transport in the 3D structure. We hypothesized that the addition of endothelial cells (ECs) may improve osteogenesis and prevent necrosis of engineered bone via effective neovascularization. Osteoblasts and ECs were differentiated from bone marrow of BALB/c mice, and their phenotypes were confirmed prior to implantation. Cylindrical porous polycaprolactone (PCL)‐hydroxyapatite (HA) scaffolds were synthesized. ECs were seeded on scaffolds followed by seeding of osteoblasts in the EC‐OB group. In the OB group, scaffolds were only seeded with osteoblasts. The cell‐free scaffolds were denoted as control group. A 0.4‐cm‐long segmental femur defect was established and replaced with the grafts. The grafts were evaluated histologically at 6 weeks postimplantation. In comparison with the OB group, the EC‐OB group resulted in a widely distributed capillary network, osteoid generated by osteoblasts and absent ischemic necroses. Pre‐seeding scaffold with ECs effectively promoted neovascularization in grafts, prevented the ischemic necrosis, and improved osteogenesis. The integration of bone marrow‐derived ECs and osteoblasts in porous scaffold is a useful strategy to achieve engineered bone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1147–1152, 2008     

Bone mineralization defects and vitamin D deficiency: Histomorphometric analysis of iliac crest bone biopsies and circulating 25‐hydroxyvitamin D in 675 patients

Parathyroid hormone (PTH) is only one measurable index of skeletal health, and we reasoned that a histomorphometric analysis of iliac crest biopsies would be another and even more direct approach to assess bone health and address the required minimum 25‐Hydroxyvitamin D [25(OH)D] level. A cohort from the northern European population with its known high prevalence of vitamin D deficiency therefore would be ideal to answer the latter question. We examined 675 iliac crest biopsies from male and female individuals, excluding all patients who showed any signs of secondary bone diseases at autopsy. Structural histomorphometric parameters, including osteoid indices, were quantified using the Osteomeasure System according to ASBMR standards, and serum 25(OH)D levels were measured for all patients. Statistical analysis was performed by Student's t test. The histologic results demonstrate an unexpected high prevalence of mineralization defects, that is, a pathologic increase in osteoid. Indeed, 36.15% of the analyzed patients presented with an osteoid surface per bone surface (OS/BS) of more than 20%. Based on the most conservative threshold that defines osteomalacia at the histomorphometric level with a pathologic increase in osteoid volume per bone volume (OV/BV) greater than 2% manifest mineralization defects were present in 25.63% of the patients. The latter were found independent of bone volume per trabecular volume (BV/TV) throughout all ages and affected both sexes equally. While we could not establish a minimum 25(OH)D level that was inevitably associated with mineralization defects, we did not find pathologic accumulation of osteoid in any patient with circulating 25(OH)D above 75 nmol/L. Our data demonstrate that pathologic mineralization defects of bone occur in patients with a serum 25(OH)D below 75 nmol/L and strongly argue that in conjunction with a sufficient calcium intake, the dose of vitamin D supplementation should ensure that circulating levels of 25(OH)D reach this minimum threshold (75 nmol/L or 30 ng/mL) to maintain skeletal health. © 2010 American Society for Bone and Mineral Research     

Enhanced healing of goat femur‐defect using BMP7 gene‐modified BMSCs and load‐bearing tissue‐engineered bone

Segmental defect regeneration is still a clinical challenge. In this study, we investigated the feasibility of bone marrow stromal cells (BMSCs) infected with adenoviral vector containing the bone morphogenetic protein 7 gene (AdBMP7) and load‐bearing to enhance bone regeneration in a critically sized femoral defect in the goat model. The defects were implanted with AdBMP7‐infected BMSCs/coral (BMP7 group) or noninfected BMSCs/coral (control group), respectively, stabilized with an internal fixation rod and interlocking nails. Bridging of the segmental defects was evaluated by radiographs monthly, and confirmed by biomechanical tests. Much callus was found in the BMP7 group, and nails were taken off after 3 months of implantation, indicating that regenerated bone in the defect can be remodeled by load‐bearing, whereas after 6 months in control group. After load‐bearing, it is about 5 months; the mechanical property of newly formed bone in the BMP7 group was restored, but 8 months in control group. Our data suggested that the BMP7 gene‐modified BMSCs and load‐bearing can promote bone regeneration in segmental defects. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:412–418, 2010     

Promotion of acute‐phase skin wound healing by Pseudomonas aeruginosa C4‐HSL

A Pseudomonas aeruginosa quorum‐sensing system, which produces N‐(3‐oxododecanoyl)‐l ‐homoserine lactone (3‐oxo‐C₁₂‐HSL) and N‐butanoyl‐l ‐homoserine lactone (C₄‐HSL), regulates the virulence factors. In our previous study, 3‐oxo‐C₁₂‐HSL, encoded by lasI gene, was shown to promote wound healing. However, the effect of C₄‐HSL, encoded by rhlI gene, remains to be elucidated. We addressed the effect of C₄‐HSL on wounds in P. aeruginosa infection. Wounds were created on the backs of Sprague–Dawley SD rats, and P. aeruginosa PAO1 (PAO1) or its rhlI deletion mutant (ΔrhlI) or lasI deletion mutant (ΔlasI) was inoculated onto the wound. Rats were injected intraperitoneally with anti‐C₄‐HSL antiserum or treated with C₄‐HSL at the wound surface. PAO1 inoculation led to significant acceleration of wound healing, which was associated with neutrophil infiltration and TNF‐α synthesis. These responses were reversed, except for TNF‐α production, when ΔrhlI was inoculated instead of PAO1 or when rats were co‐treated with PAO1 and anti‐C₄‐HSL antiserum . In contrast, the healing process and neutrophil infiltration, but not TNF‐α synthesis, were accelerated when C₄‐HSL was administered in the absence of PAO1. This acceleration was not affected by anti‐TNF‐α antibody. These results suggest that C₄‐HSL may be involved in the acceleration of acute wound healing in P. aeruginosa infection by modifying the neutrophilic inflammation.     

Effect of cavity preparation and bone mineral density on bone‐interface densification and bone‐implant contact during press‐fit implantation of hip stems

Implant loosening and periprosthetic fracture are two major revision causes for uncemented hip stems. The chosen method of cavity preparation could play a key role for both failure mechanisms. The aim of this study was to determine the dependence of the broach type as well as patient bone mineral density (BMD) on densification and contact conditions at the bone‐implant interface. Hip stems were implanted into cadaveric femora using compaction, blunt extraction or sharp extraction broaches with computed tomography scans performed prior to broaching, after broaching and after stem implantation. Proximal periprosthetic bone densification as well as press‐fit, contact area and stem seating relative to the last broach were determined. Median bone densification was higher with the compaction and blunt extraction broaches compared to sharp extraction broaches (181% and 177%, respectively, p = 0.002). The bone densification of femora prepared with compaction broaching increased with higher BMD (R² = 0.183, p = 0.037), while stem seating decreased with higher BMD for all broach types (R² = 0.259, p = 0.001). Incomplete seated prostheses were associated with smaller press‐fit and bone‐implant contact area (R² = 0.249, p = 0.001; R² = 0.287, p < 0.001). Clinical Significance: The results suggest that compaction broaching maximizes bone densification in patients with higher bone density. However, there appears to be an increased risk of insufficient stem seating in high‐density bone that could limit the benefits for primary stability. For lower quality bone, the broach type appears to play a lesser role, but care must be taken to limit extensive stem seating which might increase periprosthetic fracture risk. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1580–1589, 2019.     

Local administration of alendronate reduced peri‐tunnel bone loss and promoted graft‐bone tunnel healing with minimal systemic effect on bone in contralateral knee

Continued systemic administration of alendronate was reported to reduce peri‐tunnel bone resorption and promoted graft‐bone tunnel healing at the early stage post‐anterior cruciate ligament (ACL) reconstruction. However, systemic increase in bone mineral density (BMD) in the contralateral intact knee was observed. We tested if single local administration of alendronate into the bone tunnel during ACL reconstruction could achieve similar benefits yet without the systemic effect on bone. Seventy‐two rats with unilateral ACL reconstruction were divided into three groups: saline, low‐dose (6 μg/kg) and mid‐dose (60 μg/kg) alendronate. For local administration, alendronate was applied to the bone tunnels for 2 min before graft insertion and repair. At weeks 2 and 6, the reconstructed complex was harvested for high‐resolution computed tomography (vivaCT) imaging followed by biomechanical test or histology. Our results showed that local administration of low‐dose alendronate showed comparable benefits on the reduction of peri‐tunnel bone loss, enhancement of bone tunnel mineralization, tunnel graft integrity, graft osteointegration and mechanical strength of the reconstructed complex at early stage post‐reconstruction, yet with minimal systemic effect on mineralized tissue at the contralateral intact knee. A single local administration of alendronate at the low‐dose therefore might be used to promote early tunnel graft healing post‐reconstruction. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1897–1906, 2013     

Influence of the ratio of particulate autogenous bone graft/platelet‐rich plasma on bone healing in critical‐size defects: A histologic and histometric study in rat calvaria

The purpose of this study was to analyze histomorphometrically the influence of the ratio of particulate autogenous bone (AB) graft/platelet‐rich plasma (PRP) on bone healing in surgically created critical‐size defects (CSD) in rat calvaria. Fifty rats were divided into five groups: Group C (control), Group AB, Group AB/PRP‐50, Group AB/PRP‐100, and Group AB/PRP‐150. A 5‐mm diameter critical‐size defect was created in the calvarium of each animal. In Group C, the defect was filled by blood clot only. In Group AB, the defect was filled with 0.01 mL of AB graft. In Groups AB/PRP‐50, AB/PRP‐100, and AB/PRP‐150, the defects were filled with 0.01 mL of AB graft combined with 50, 100, and 150 µL of PRP, respectively. All animals were euthanized at 30 days postoperative. Histomorphometry, using image analysis software, and histology analyses were performed. New Bone Area (NBA) and the remaining bone graft particles area (RPA) were calculated as a percentage of the total area of the original defect. Percentage data were transformed into arccosine for analysis. No defect completely regenerated with bone. Group AB/PRP‐50 (41.78 ± 13.48%) had a significantly greater NBA than Groups C (19.29 ± 5.11%), AB (27.43 ± 10.90%) or AB/PRP‐150 (19.17 ± 8.45%) (p < 0.05). No significant differences were observed between groups AB/PRP‐50 and AB/PRP‐100 or among groups AB, AB/PRP‐100, and AB/PRP‐150 with regard to NBA (p > 0.05). Group AB/PRP‐150 (31.59 ± 3.22%) had a significantly greater RPA than Groups AB (19.09 ± 5.21%), AB/PRP‐50 (17.33 ± 4.43%), and AB/PRP‐100 (19.72 ± 3.62%) (p < 0.001). No significant differences were observed among groups AB, AB/PRP‐50, and AB/PRP‐100 with regard to RPA (p > 0.05). The ratio AB graft/PRP influences bone healing in surgically created CSD in rat calvaria. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:468–473, 2010