Amstutz H C, O'Carroll P F, Kabo J M, Kim W C
Hip. 1985:235-49.
Bone ingrowth in the porous canine implants does occur; the early clinical results are indeed encouraging and justify further investigation. The quality of ingrowth as measured by depth and extent in the dog was stress-related. Remodelling was superior in the more compliant or elastic acetabular components without an interposed metal shell. No human specimens have been retrieved thus far, but we are encouraged because the results in the canine model with acrylic-fixed implants were comparable to the results we subsequently observed in human THARIES implantation. Those were initially excellent, but with time radiolucencies increased and loosening occurred. The quality of the canine biologic ingrowth suggests optimism for secure and durable fixation. Our patients have continued to improve through the follow-up period. There has not been a single case in which a qualitative increase in pain occurred over the cemented versions after operation. The technical problems of the surgical procedure have been overcome, but it must be performed precisely to achieve the initial inherent stability to assist in biologic ingrowth. The operative procedures in this series have been performed by or under the direct supervision of the senior author. As our competence has grown, we have applied the procedure to younger patients and those who have bone stock deficiency. One of the major advantages of the biologic ingrowth systems is the facility to graft cysts and defects. For humans, the current chamfered cylinder is an extremely bonestock-conservative procedure when combined with reaming of the femoral head to the neck size. Although space is limited in resurfacing, we have been able to achieve a minimum 4-mm bearing thickness of polyethylene. We believe that the compliant mesh chamfered cylinder system provides excellent stability. However, the hemispheric component, although technically more difficult to seat and fix, has definite applications in bonestock deficiency and with further refinement will be useful in primary replacements as well. Nevertheless, because of the uncertain future of any type of implant, especially new, we have encouraged the patients to follow a careful postoperative management program and refrain from heavy activity during the first year. Many are active and some are now participating in athletics, although this is certain to shorten the life of these implants just as was observed in acrylic-fixed devices. The biologic problems of interface corrosion, migration, and metal ion transfer indicate that these implants must be followed for longer periods. Therefore it seems unwise to extend this technology to a wide clinical use at this time.
多孔犬类植入物中确实会发生骨长入；早期临床结果确实令人鼓舞，值得进一步研究。在犬类中，通过深度和范围测量的长入质量与应力相关。在没有中间金属壳的更柔顺或有弹性的髋臼组件中，重塑效果更好。到目前为止尚未获取到人类标本，但我们受到鼓舞，因为丙烯酸固定植入物在犬类模型中的结果与我们随后在人类THARIES植入中观察到的结果相当。那些最初效果很好，但随着时间推移，出现了射线可透性增加和松动的情况。犬类生物长入的质量表明对安全和持久固定持乐观态度。在随访期间，我们的患者持续改善。术后没有一例患者的疼痛程度比骨水泥型患者有质性增加。手术操作的技术问题已得到克服，但必须精确进行以实现初始的固有稳定性，以促进生物长入。本系列中的手术操作均由资深作者本人或在其直接监督下进行。随着我们能力的提升，我们已将该手术应用于更年轻的患者以及骨量不足的患者。生物长入系统的主要优点之一是便于移植囊肿和骨缺损。对于人类而言，当前的倒角圆柱体与将股骨头扩孔至颈部尺寸相结合时，是一种极其节省骨量的手术方法。尽管表面置换的空间有限，但我们已能够实现至少4毫米厚的聚乙烯承重厚度。我们认为柔顺网眼倒角圆柱体系统提供了出色的稳定性。然而，半球形组件虽然在技术上更难安装和固定，但在骨量不足的情况下有明确的应用，并且经过进一步改进后在初次置换中也将有用。尽管如此，由于任何类型的植入物，尤其是新型植入物的未来存在不确定性，我们已鼓励患者遵循仔细的术后管理方案，并在第一年避免剧烈活动。许多患者现在很活跃，有些甚至参加体育活动，尽管这肯定会缩短这些植入物的使用寿命，就像在丙烯酸固定装置中观察到的那样。界面腐蚀、移位和金属离子转移等生物学问题表明，必须对这些植入物进行更长时间的随访。因此，目前将这项技术广泛应用于临床似乎不明智。
