Gronewold Jens, Berner Sebastian, Olender Gavin, Hurschler Christof, Windhagen Henning, von Lewinski Gabriela, Floerkemeier Thilo
Department of Orthopedic Surgery, Hannover Medical School , Germany.
Biomechanics and Biomaterials Laboratory, Hannover Medical School , Germany.
Orthop Rev (Pavia). 2014 Mar 18;6(1):5211. doi: 10.4081/or.2014.5211. eCollection 2014 Jan 20.
Short stem hip arthroplasties with predominantly metaphyseal fixation, such as the METHA® stem (Aesculap, Tuttlingen, Germany), are recommended because they are presumed to allow a more physiologic load transfer and thus a reduction of stress-shielding. However, the hypothesized metaphyseal anchorage associated with the aforementioned benefits still needs to be verified. Therefore, the METHA short stem and the Bicontact® standard stem (Aesculap, Tuttlingen, Germany) were tested biomechanically in synthetic femora while strain gauges monitored their corresponding strain patterns. For the METHA stem, the strains in all tested locations including the region of the calcar (87% of the non-implanted femur) were similar to conditions of synthetic bone without implanted stem. The Bicontact stem showed approximately the level of strain of the non-implanted femur on the lateral and medial aspect in the proximal diaphysis of the femur. On the anterior and posterior aspect of the proximal metaphysis the strains reached averages of 78% and 87% of the non-implanted femur, respectively. This study revealed primary metaphyseal anchorage of the METHA short stem, as opposed to a metaphyseal-diaphyseal anchorage of the Bicontact stem.
推荐使用主要通过干骺端固定的短柄髋关节置换假体，如METHA®柄（德国图特林根的蛇牌公司），因为据推测它们能实现更符合生理的负荷传递，从而减少应力遮挡。然而，与上述益处相关的假定干骺端锚固仍需验证。因此，在合成股骨上对METHA短柄和Bicontact®标准柄（德国图特林根的蛇牌公司）进行了生物力学测试，同时应变片监测它们相应的应变模式。对于METHA柄，包括股骨矩区域（未植入柄的股骨的87%）在内的所有测试部位的应变与未植入柄的合成骨的情况相似。Bicontact柄在股骨近端骨干的外侧和内侧显示出与未植入柄的股骨大致相同的应变水平。在近端干骺端的前侧和后侧，应变分别达到未植入柄的股骨的78%和87%的平均值。这项研究揭示了METHA短柄主要通过干骺端锚固，而Bicontact柄则是通过干骺端-骨干锚固。
