Skripitz R, Johansson H R, Ulrich S D, Werner A, Aspenberg P
Department of Orthopedic Surgery, University Hospital Rostock, 142 Doberaner Strasse, Rostock, D-18057, Germany.
J Orthop Sci. 2009 Mar;14(2):138-43. doi: 10.1007/s00776-008-1311-x. Epub 2009 Apr 1.
Intermittent administration of parathyroid hormone (PTH) leads to bone formation by increasing osteoblast numbers and activity levels. Animal studies have shown that intermittent PTH administration increases implant fixation in normal rats. The purpose of this study was to analyze the osseous incorporation of an implant in osteoporotic rats while treating them with intermittent PTH (1-34) or alendronate.
A total of 36 ovariectomized (OVX) Wistar rats were randomized into three groups. Polymethylmethacrylate cement rods were implanted in one tibia in each rat. The three groups received daily PTH (60 mug/kg body weight [BW]), alendronate (200 mug/kg BW), or saline (0.5 ml/kg BW). A sham-ovariectomized group (n = 12) was treated with saline. After 2 weeks, the area around the implants was analyzed by histomorphometry for bone volume density (BVD) and implant bone contact. Bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry.
The BVD was higher in the specimens treated with PTH than in the other groups. PTH improved the BVD, BMD, and implant bone contact. Alendronate doubled the implant bone contact compared to the OVX and sham groups but did not improve BVD or BMD.
These findings confirm that intermittent PTH enhances implant fixation in osteoporotic bone. The clinical significance of these findings is that application of intermittent PTH may be beneficial for early implant fixation in fractures, nonunions, and prosthetic replacements when bone density is decreased.
间歇性给予甲状旁腺激素（PTH）可通过增加成骨细胞数量和活性水平来促进骨形成。动物研究表明，间歇性给予PTH可增加正常大鼠体内植入物的固定。本研究的目的是分析在骨质疏松大鼠中用间歇性PTH（1-34）或阿仑膦酸盐治疗时植入物的骨结合情况。
总共36只去卵巢（OVX）的Wistar大鼠被随机分为三组。在每只大鼠的一根胫骨中植入聚甲基丙烯酸甲酯骨水泥棒。三组分别每日接受PTH（60微克/千克体重[BW]）、阿仑膦酸盐（200微克/千克BW）或生理盐水（0.5毫升/千克BW）。假去卵巢组（n = 12）用生理盐水治疗。2周后，通过组织形态计量学分析植入物周围区域的骨体积密度（BVD）和植入物与骨的接触情况。通过双能X线吸收法评估骨密度（BMD）。
用PTH治疗的标本中的BVD高于其他组。PTH改善了BVD、BMD和植入物与骨的接触。与OVX组和假手术组相比，阿仑膦酸盐使植入物与骨的接触增加了一倍，但未改善BVD或BMD。
这些发现证实间歇性PTH可增强骨质疏松骨中植入物的固定。这些发现的临床意义在于，当骨密度降低时，应用间歇性PTH可能有利于骨折、骨不连和假体置换中植入物的早期固定。
