金属与羟基磷灰石微孔表面股骨植入体与骨结合强度的比较研究

目的比较金属与羟基磷灰石(hydroxyapatite,HA)微孔表面股骨植入体与骨的结合强度.方法用等离子喷涂技术,分别喷涂HA微粒和钴铬钼合金微粒于不锈钢三棱针表面,配对植入15只成年家兔的股骨,饲养2个月作拔出试验,并比较手术当日与2个月后的X线改变.结果HA与钴铬钼合金涂层三棱针平均剪切强度分别为(0.98±0.12)MPa和(0.65±0.15)MPa,二者有显著性差异(P＜0.05).X线片HA涂层三棱针周围有较多的成骨反应,透明区较金属涂层三棱针要少而窄.结论植入兔的股骨短时间内,HA微孔表面植入体较金属微孔表面植入体更为稳定.     

等离子喷涂硅灰石涂层种植体体内植入的实验研究

目的对硅灰石（CaSiO3）涂层的生物学性能进行评价,为临床选择种植体表面改性方法提供实验依据。方法在纯钛棒表面采用等离子喷涂的方法分别加涂CaSiO3涂层和羟基磷灰石（HA）涂层,切割成直径3mm、高12mm的圆柱状植入体各12枚,植入实验狗的下颌骨内,检测种植体-骨界面的结合强度,并用扫描电镜进行形态观测。结果植入3个月后,CaSiO3涂层种植体-骨界面的剪切结合强度高于HA涂层种植体-骨界面的剪切结合强度,二者之间有显著差异（P〈0．05）。结论CaSiO3涂层具有良好的生物活性,是一种较有应用前途的种植体涂层材料。     

羟基磷灰石喷涂钛质解剖柄股骨假体在全髋关节置换术中的应用

目的对全髋关节置换术(THA)中使用的近端羟基磷灰石喷涂钛质解剖柄股骨假体的手术效果进行评估。方法回顾性分析了采用羟基磷灰石喷涂钛质解剖柄股骨假体对146例178个髋进行的人工THA的资料。对其中130例163个髋关节进行平均51·3个月的随访,通过Harris评分及X线片评价临床效果。结果Harris评分的优良率达94·5%。X线片未见假体松动和骨溶解,假体均达到骨长入性稳定。结论羟基磷灰石喷涂钛质解剖柄股骨假体用于人工THA,短期效果满意。     

人工股骨柄真空等离子喷涂Ti基层的HA-Ti阶梯式涂层的力学性能

我们基于真空下在犬工股骨柄上等离子喷涂纯钛(Ti)后再复合羟基磷灰石(HA) -Ti阶梯式涂层,探讨该复合阶梯式涂层的力学性能和固定关节假体的可行性.     

纳米级羟基磷灰石梯度涂层植入体骨结合的研究

目的评价纳米级羟基磷灰石梯度涂层(HAP)植入体-骨界面骨结合情况。方法在Beagle犬股骨内植入纳米级HAP梯度涂层栓、普通级HAP涂层栓和钛合金(Ti-6AL-4V)栓,在4、8、12周比较X线结果和植入体-骨界面剪切强度。结果各时间点纳米级HAP涂层组和普通HAP梯度涂层组的X线结果相当,植入体-骨界面剪切强度均优于钛合金组和钛合金组。结论纳米级HAP梯度涂层植入体与骨有很好的结合力,能够加速骨质的愈合。     

人工关节非骨水泥固定方法的生物力学分析

目的　为人工关节生物固定方法的改进提供一些理论及实验依据。方法　通过推出试验 (Push out)方法对BMP2复合多孔金属表面植入体、多孔金属表面植入体、喷涂HA的PCA植入体、羟基磷灰石涂层植入体在填入骨 -假体交界面后界面的结合强度进行检测 ,并对获得的数据进行统计学分析。结果　BMP对界面结合强度有增强作用 ,在植入的早期尤其显著。结论　对植入体表面进行多孔处理并复合HA对中期促进骨与植入体结合效果显著 ,在假体制造工艺中HA涂层的制备对假体的生物固定效果有较大的影响     

人工关节非骨水泥固定方法的生物力学分析

目的 为人工关节生物固定方法的改进提供一些理论及实验依据。方法 通过推出试验(Push-out)方法对BMP2复合多孔金属表面植入体、多孔金属表面植入体、喷涂HA的PCA植入体、羟基磷灰石涂层植入体在填入骨-假体交界面后界面的结合强度进行检测，并对获得的数据进行统计学分析。结果 BMP对界面结合强度有增强作用，在植入的早期尤其显著。结论 对植入体表面进行多孔处理并复合HA对中期促进骨与植入体结合效果显著，在假体制造工艺中HA涂层的制备对假体的生物固定效果有较大的影响。     

生物活性羟基磷灰石涂层的动物实验观察

ＨＡ涂层假体有许多有关涂层的问题尚需解决。我们研制出了表面仿生型生物活性双梯度涂层 ,体外试验证实 ,界面结合强度达 3 8Ｍｐａ[1] 。1.材料和方法 :钛合金植入体 (Ｔｉ)、带羟基磷灰石涂层的钛合金植入体(ＨａＴｉ)和ｒｈＢＭＰ 2复合涂层植入体(ｒｈＢｍｐ 2ＨａＴｉ)的制备 ,其中 3 0根棒制成粗糙表面的Ｔｉ植入体 ,另外 60根予等离子喷涂制成ＨａＴｉ植入体。为长 18 0ｍｍ、直径 4 2ｍｍ。采用直接涂抹、吸收复合方法组装ｒｈＢＭＰ 2 [2 ] 。按ｒｈＢＭＰ 22 5ｍｇ/个植入体复合。共制备ｒｈＢｍｐ 2ＨａＴｉ3 0个。按术后喂养 …     

羟基磷灰石喷涂型椎间植入物与皮质骨界面的结合特性

目的 观察在生理负荷下羟基磷灰石表面喷涂型椎间植入物的界面介导皮质骨长入形成骨性结合的特性。方法 建立直立动物椎间植入物-椎体皮质骨界面研究动物模型，制作猕猴型椎间植入物12个，金刚砂磨面（对照组）4个、羟基磷灰石表面喷涂（观察组）8个。取4只成年猕猴，分别在其L2，3L3，4和L4，5椎间隙随机放置2个羟基磷灰石喷涂及1个金刚砂磨面植入物。于术后3、6、12、24、40周行X线摄片，40周非脱钙骨切片行骨界面形态计量学分析及组织学观察。结果 术后第3天全部动物恢复站立，行走，步态正常。观察期间植入物无松动及移位。术后40周观察组骨界面主要以部分矿化的类骨质及钙化良好的成熟骨组织充填，单位视野成骨细胞和骨细胞数明显增多（t=16．983，P=0．000），矿化骨组织百分含量高于对照组（t=5．001，P=0．000）。羟基磷灰石涂层无碎裂及剥脱，与骨组织界面密合。结论 羟基磷灰石与椎体皮质骨具有良好的组织相容性，在体内性质稳定，在椎间压应力生理负荷下，较金刚砂磨面能更好地介导椎体皮质骨组织长入骨界面，形成骨性结合。     

锁定钢板结合羟基磷灰石表面喷涂锁定螺钉内固定治疗骨质疏松性肱骨近端骨折

目的探讨锁定钢板结合羟基磷灰石表面喷涂锁定螺钉内固定治疗骨质疏松性肱骨近端骨折的疗效。方法经肩关节前入路进入复位后,对仍有明显骨质缺损的部位行人工骨植骨,使用锁定钢板结合带羟基磷灰石表面喷涂的锁定螺钉内固定治疗。结果 17例获随访6～23个月,无肱骨头坏死,骨折对位对线良好,按Neer功能评分标准:优14例,良3例。结论对于骨质疏松,骨质缺损严重肱骨近端骨折者,可行锁定钢板结合带羟基磷灰石表面喷涂的锁定螺钉内固定治疗,疗效可靠。     

Loss of hydroxyapatite coating on retrieved,total hip components

The goal of this study was to examine the early retrievals of hydroxyapatite-(HA) coated hip prostheses to assess evidence of osteoconductivity, resorption of HA, and the integrity of the HA/implant bond. Six retrieved HA-coated hip prostheses (3 femoral hip stems, 3 acetabular cups) were analyzed for the amount of bone ongrowth or ingrowth of the HA-coated surface and the extent to which the coating was still present after in vivo service. The examination of these six HA-coated prostheses indicates that HA appeared to be osteoconductive. There was evidence of debonding of HA from the smooth-surfaced femoral prosthesis, although that may have been a result of the extraction process. The five plasma-spray surfaced, HA-coated prostheses showed evidence of considerable loss of the HA coating at the time of receipt in the authors' laboratory, although it is was not possible to determine the cause of the loss of coating.     

Tissue reactions around a hydroxyapatite-coated hip prosthesis: Case report of a retrieved specimen

Bone reactions were studied around a titanium, hydroxyapatite (HA)-coated Osteonics (Allendale, NJ) bipolar hip prosthesis, which was revised for severe midthigh pain 4 years after implantation. Inspection of the retrieved prosthesis using a dissecting microscope revealed scarce remnants of a coating-like material on the surface of the prosthesis; however, histology of this layer and histology of the bony side of the bone—HA interface failed to reveal any remnants of an HA coating. The interface was covered predominantly by trabecular bone, which closely followed the contour of the prosthesis, and was partly woven nonmineralized bone. At locations where mineralized bone faced the prosthesis, many small dark titanium wear particles were found. Similar particles were found in macrophages in the intertrabecular medullary space. Polyethylene wear particles were specifically located in macrophages in a soft tissue interface at more distal levels along the stem of the prosthesis. Although the observations presented in this case cannot be generalized, it clearly shows that the HA coating layer had completely disappeared after 4 years. More detailed retrieval studies and longer clinical follow-up studies are needed before a final evaluation of the behavior of HA coatings and long-term fixation of HA-coated prostheses can be made.     

Functional osseointegration of hydroxyapatite-coated implants in a weight-bearing canine model

That hydroxyapatite (HA) can form a strong chemical bond with bone has been confirmed by several precedent workers using unloaded implants. The relation-ship between the histomorphometric measurements of the interface of the cementless femoral stems with and without HA coating and their mechanical properties in a weight-bearing canine model was evaluated in this study. Seven HA-coated and seven uncoated titanium (Ti6Al4V) hemiarthroplasties were implanted in the right hip of 14 dogs for a 5-month period. The specimens were taken to conduct mechanical testing andmorphometric measuring. The average interface shear strength of 2.13 MPa for the HA-coated specimens was significantly higher than 0.93 MPa for the uncoated specimens (P<.05). There was greater bone apposition with the HA coating (72.39%) than without the coating (15.96%). Bone interfaces were divided into tow types histomorphometrically: type A, simple bony shell without supporting trabeculae and type B, buttressed bony shell with supporting trabeculae. A positive correlation between the type B HA-bone interface and interface shear strength was found (r=.81)     

Comparison of the early healing course of porous titanium with hydroxyapatite-coated porous titanium hip implants: clinical considerations for the use of hydroxyapatite coating in total hip replacement

The role of hydroxyapatite (HA) coating in the fixation of human total joint prostheses remains to be established. Results of animal studies have been favorable, showing very rapid bone formation with a corresponding increase in bone-implant bond strength. In addition, the quantity of bone may be increased. This study compared identical porous titanium primary total hip implants with and without HA in similar patient populations. All of these patients were healthy and reliable, and had optimal bone geometry and bone quality for cementless fixation. The purpose of the study was to contrast the sequence of events, in the first year after surgery, between the two implant groups to identify the contribution of HA to early patient function and early radiographic appearance of the prosthesis. No significant clinical difference could be demonstrated between the two groups at 1 year from surgery. However, the HA group progressed more rapidly when comparing clinical scores at 6 months (P = .0058), and appeared to demonstrate more rapid bone remodeling at 6 months on the femoral side, although this observation did not quite make statistical significance (P = .0618). There was no difference between the acetabular components during the course of this study.     

Bone graft incorporation around titanium-alloy- and hydroxyapatite-coated implants in dogs.

To evaluate cancellous allogenic bone graft incorporation into porous-coated implants, the fixation of titanium alloy-(Ti) and hydroxyapatite-(HA) coated implants with and without bone graft was compared. An unloaded model with unilateral carragheenin-induced osteopenia of the knee was used in 12 mature dogs. Ti- and HA-coated cylinders were implanted in the distal femoral condyles and centralized in 2-mm overreamed drill holes. Allogenic, fresh-frozen (-80 degrees) cancellous bone graft was packed around the implants in six dogs. In a matched group of six other dogs, the implants were left in overreamed canals without bone graft. After six weeks the interface shear strength of grafted Ti-coated implants had significantly increased compared to the nongrafted Ti implants. However, HA coating used without bone graft was capable of enhancing the bone-implant interface shear strength to nearly the same degree. The fixation of grafted Ti- and HA-coated implants was equal. No significant difference in implant fixation was found between osteopenic and control bone. Histomorphometric evaluation of mineralizing surfaces in direct contact with the implant confirmed the results from the push-out test. Bone-implant fixation when using allogeneic fresh-frozen cancellous bone graft in osteopenic and control bone was enhanced by hydroxyapatite coating but the HA coating alone appeared to offer almost the same improvement in anchorage in 2-mm defects. Loss of bone stock around loose prosthetic implants often requires bone grafting. However, because of anatomic constraints in joint prosthetic surgery, a complete filling of defects with bone graft is difficult, and areas of gaps between bone and implant will remain. Provided mechanical stability of the prosthesis, the results reported here suggest that these areas will probably be filled early with new mineralizing bone if the prosthesis is coated with a thin layer of hydroxyapatite.     

Measurement of extent of bone ongrowth and hydroxyapatite absorption in retrieved acetabular cups

BACKGROUND: To understand why hydroxyapatite (HA)-coated acetabular cups did not produce satisfactory results, we measured the extent of bone ongrowth and HA absorption of the retrieved cups. METHODS: Between March 1992 and June 1998, a total of 289 patients underwent total hip arthroplasty with an HA-coated ABG (Anatomical Benoist Giraud) prosthesis in our hospital. We revised 71 cups in our hospital, 43 of which were included in this study. The cups were in situ for an average of 80.4 months. We revised 21 cups for polyethylene wear and osteolysis, 20 for loosening, and 2 for recurrent dislocation. The outer surfaces of the cups were subdivided by two circular grooves into three areas: central, middle, peripheral. Bone ongrowth and HA absorption was measured in terms of area and thickness. The areas were graphically calculated using a computer imaging analysis system. The thickness of the HA coating remaining on the retrieved cup was measured by an x-ray coating thickness measurement instrument. RESULTS: Of the 43 cups, 37 had bone ongrowth. Bone ongrowth was observed on the central surface in 23 cups, on the middle surface in 27 cups, and on the peripheral surface in 15 cups; 6 of the 37 cups had bone ongrowth only in the groove. Altogether, 37 cups showed bone ongrowth on 6.43% of the outer acetabular surface. HA absorption appeared in all 43 cups, and an average 63.21% of the HA coating area was absorbed. there was a proportional relation between the rate of HA absorption and implantation duration, but there was no consistent trend between the thickness of the HA coating and implantation duration. CONCLUSIONS: We suggest that progressive HA absorption and minimal bone ongrowth are related to the failure of HA-coated acetabular cups at long-term follow-up after total hip arthroplasty.     

Silver oxide‐containing hydroxyapatite coating supports osteoblast function and enhances implant anchorage strength in rat femur

Antibacterial silver with hydroxyapatite (Ag–HA) is a promising coating material for imparting antibacterial properties to implants. We previously reported that 3% (w/w) silver with HA (3% Ag–HA) has both antibacterial activity and osteoconductivity. In this study, we investigated the effects of Ag–HA on the in vitro osteoblast function and the in vivo anchorage strength and osteoconductivity of implants. Production of the osteoblast marker alkaline phosphatase, but not cytotoxicity, was observed in cells of the osteoblast cell line MC3T3‐E1 cultured on the 3% Ag–HA‐coated surface. These results were similar to those observed with silver‐free HA coating. In contrast, a significant high level of cytotoxicity was observed when the cells were cultured on a 50% Ag–HA‐coated surface. The anchorage strength of implants inserted into the femur of Sprague–Dawley (SD) rats was enhanced by coating the implants with 3% Ag–HA. On the 3% Ag–HA‐coated surface, both metaphyseal and diaphyseal areas were largely covered with new bone and had adequate osteoconductivity. These results suggest that 3% Ag–HA, like conventional HA, promotes osteogenesis by supporting osteoblast viability and function and thereby contributes to sufficient anchorage strength of implants. Application of 3% Ag–HA, which combines the osteoconductivity of HA and the antibacterial activity of silver, to prosthetic joints will help prevent postoperative infections. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1391–1397, 2015.     

Interfacial shear strength of bioactive‐coated carbon fiber reinforced polyetheretherketone after in vivo implantation

Despite the excellent osseointegration of carbon‐fiber‐reinforced polyetheretherketone (CFR/PEEK) with a surface hydroxyapatite (HA) coating, the bone‐implant interfacial shear strength of HA‐coated CFR/PEEK after osseointegration is unclear. We examined the interfacial shear strength of HA‐coated CFR/PEEK implants after in vivo implantation in a rabbit femur‐implant pull‐out test model. HA coating was performed by a newly developed method. Uncoated CFR/PEEK, HA‐coated blasted titanium alloy, and uncoated blasted titanium alloy were used as control implants. The implants were inserted into drilled femoral cortex, and pull‐out tests were conducted after 6 and 12 weeks of implantation to determine maximum interfacial shear strength. The HA‐coated CFR/PEEK (15.7 ± 4.5 MPa) and HA‐coated titanium alloy (14.1 ± 6.0 MPa) exhibited significantly larger interfacial shear strengths than the uncoated CFR/PEEK (7.7 ± 1.8 MPa) and the uncoated titanium alloy (7.8 ± 2.1 MPa) at 6 weeks. At 12 weeks, only the uncoated CFR/PEEK (8.3 ± 3.0 MPa) exhibited a significantly smaller interfacial shear strength, as compared to the HA‐coated CFR/PEEK (17.4 ± 3.6 MPa), HA‐coated titanium alloy (14.2 ± 4.8 MPa), and uncoated titanium alloy (15.0 ± 2.6 MPa). Surface analysis of the removed implants revealed detachment of the HA layer in both the HA‐coated CFR/PEEK and titanium alloy implants. The proposed novel HA coating method of CFR/PEEK significantly increased interfacial shear strength between bone and CFR/PEEK. The achieved interfacial shear strength of the HA‐coated CFR/PEEK implant is of the same level as that of grit‐blasted titanium alloy with HA. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1618–1625, 2012     

The role of hydroxyapatite coating in joint replacement surgery – Key considerations

The use of a porous hydroxyapatite (HA) coating has definitively increased the durability and biocompatibility of joint replacement prostheses (JRP) since its introduction. This article will contextualise the properties of porous HA and relate these characteristics to its clinical function. Novel strategies to encourage osseointegration will also be explored, alongside their clinical relevance. All major literature databases were scrutinised for literature relevant to the scope of our review. The role of Hydroxyapatite was evaluated, alongside further strategies to augment bone ingrowth. HA coatings remain the most optimal coating for widespread clinical use. Advantages are conferred due to the method of application, the tribology and the biocompatibility of the material. Further strategies are available to augment bone ingrowth, pertaining to biological modifications and implantation of external factors. An evaluation of the literature has described the relative long term performance of the HA coated JRPs both in isolation and when compared with cemented prosthesis. Metanalyses have shown HA coated JRPs to perform as well as cemented prosthesis in terms of survivability over both short and long term follow ups. Concerning strategies to augment osseointegration, consideration should be given to form and function of the coating surface, as this provides the basis for cell adherence, proliferation, and differentiation.     

Ceramic coating improves tibial component fixation in total knee arthroplasty

Forty uncemented total knee arthroplasties (36 patients) were randomly allocated to a Miller-Galante II prosthesis with or without hydroxyapatite/tricalcium phosphate (HA/TCP) coating on the titanium fiber mesh on the undersurface of the tibial component. The patients were followed for 2 years with repeated radiostereometric examinations. After 2 years, the HA/TCP tibial components displayed smaller anterior-posterior tilt and less subsidence. The mean value of maximal total point motion was small: 0.5 mm in both groups. At 24 months, there were more radiolucent lines under the tibial tray and around the stem in the uncoated group, but the clinical results did not differ. HA/TCP coating on the undersurface of the tibial component improved the stability and seemed to improve the quality of the interface between the tibial component and the bone.