Laboratory of Biomechanics and Implant Research, Department of Orthopedics and Traumatology, University Hospital Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany,
Arch Orthop Trauma Surg. 2014 May;134(5):719-26. doi: 10.1007/s00402-014-1946-3. Epub 2014 Feb 13.
Conventional cementless total hip arthroplasty already shows very good clinical results. Nevertheless, implant revision is often accompanied by massive bone loss. The new shorter GTS™ stem has been introduced to conserve femoral bone stock. However, no long-term clinical results were available for this implant. A biomechanical comparison of the GTS™ stem with the clinically well-established CLS(®) stem was therefore preformed to investigate the targeted stem philosophy.
Four GTS™ stems and four CLS(®) stems were implanted in a standardized manner in eight synthetic femurs. A high-precision measuring device was used to determine micromotions of the stem and bone during different load applications. Calculation of relative micromotions at the bone-implant interface allowed the rotational implant stability and the bending behavior of the stem to be determined.
Lowest relative micromotions were detected near the lesser trochanter within the proximal part of both stems. Maximum relative micromotions were measured near the distal tip of the stems, indicating a proximal fixation of both stems. For the varus-valgus-torque application, a comparable stem bending behavior was shown for both stems.
Both stems seem to provide a comparable and adequate primary stability. The shortened GTS™ design has a comparable rotational stability and bone-implant flexibility compared to a conventional stem. This study demonstrates that the CLS(®) stem and the GTS™ stem exhibit similar biomechanical behavior. However, a clinical confirmation of these experimental results is still required.
传统的非骨水泥全髋关节置换术已经显示出非常好的临床效果。然而，植入物的翻修常常伴随着大量的骨质流失。新型的更短的 GTS™ 柄被引入以保留股骨骨量。然而，这种植入物还没有长期的临床结果。因此，对 GTS™ 柄与临床广泛应用的 CLS® 柄进行了生物力学比较，以研究目标柄的设计理念。
在八个合成股骨中，以标准化的方式植入四个 GTS™ 柄和四个 CLS® 柄。使用高精度测量装置来测量不同负荷应用时柄和骨之间的微动。计算骨-植入物界面的相对微动，以确定旋转植入物稳定性和柄的弯曲行为。
在近端部分，两个柄的较小粗隆附近检测到最低的相对微动。在柄的远端尖端附近测量到最大的相对微动，表明两个柄都有近端固定。对于内翻-外翻-扭矩应用，两个柄显示出类似的柄弯曲行为。
两个柄似乎都提供了类似的和足够的初始稳定性。与传统柄相比，缩短的 GTS™ 设计具有类似的旋转稳定性和骨-植入物的柔韧性。本研究表明，CLS® 柄和 GTS™ 柄具有相似的生物力学行为。然而，这些实验结果仍需要临床证实。
