Background

Appropriate restoration of the native centre of rotation is of paramount importance in total hip arthroplasty. Reconstruction of the centre of rotation depends on reaming technique: conventional approaches require more cup medialization than anatomical preparations. To date, the influence of cup medialization on socket stability in cementless implants is still unknown.

Methods

Ten cadaveric hemipelvises were sequentially reamed using anatomical technique (only subchondral bone removal with restoration of the native centre of rotation) and conventional preparation (reaming to the lamina and medializing the cup). A biomechanical test was performed on the reconstructions. Implant motions were measured with digital image correlation while a cyclic load of increasing magnitude was applied.

Findings

No significant difference was measured between the two implantation techniques in terms of permanent cup migrations. The only significant difference was found for the cup inducible rotations, where the conventional technique was associated with larger rotations.

Interpretation

Conventional reaming and cup medialization do not improve initial cup stability. Beyond the recently questioned concerns about medialization and hip biomechanics, this is another issue to bear in mind when reaming the acetabulum.

中文翻译：

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杯中转对压入式髋臼杯初级稳定性的影响。

背景

在全髋关节置换术中，适当地恢复自然旋转中心至关重要。旋转中心的重建取决于铰孔技术：与解剖学准备相比，传统方法需要更多的杯中转。迄今为止，在非骨水泥植入物中，杯中转对承窝稳定性的影响仍然未知。

方法

使用解剖技术（仅去除软骨下骨并恢复自然的旋转中心）和常规制备（将其伸到椎板并使椎间盘中间），依次扩孔十个尸体半盆。对重建物进行了生物力学测试。用数字图像相关性测量植入物的运动，同时施加不断增加的周期性载荷。

发现

在永久性杯迁移方面，两种植入技术之间未测量到显着差异。发现杯感生旋转的唯一显着差异是传统技术与较大旋转相关联。

解释

传统的扩孔和杯中转不能提高杯的初始稳定性。除了最近对介导和髋部生物力学的质疑之外，这是扩孔髋臼时要记住的另一个问题。