Tung Wei Shao, Kunsel Kunsel, Roytman Gregory R, Donnelley Claire A, Pratola Donald, Tommasini Steven M, Bernstein Jenna, Wiznia Daniel H
Department of Orthopaedics and Rehabilitation, Yale University, New Haven, CT, USA.
Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
Arthroplast Today. 2024 Mar 5;26:101340. doi: 10.1016/j.artd.2024.101340. eCollection 2024 Apr.
In revision total knee arthroplasty, tibial cones have demonstrated improved longevity and reduced incidence of aseptic loosening. Several currently available "off-the-shelf" (OTS) cone systems may not have sizes to accommodate all patient bone morphologies.
Computed tomographies from one hundred primary total knee arthroplasty patients and dimensions of 4 OTS cones were obtained. Press-fit stems were positioned in 3D tibia models to fit the diaphyseal trajectory. Cones were positioned around the stem at 1, 6, and 13 mm resections measured from the trough of the medial tibial plateau, simulating proximal tibial cuts and bone loss. Tibias were examined for cortical breaching following modeled cone preparation.
Increased rate of breaching was observed as size and depth of the cone increased. In 2/49 (4.1%) male and 19/46 (41.3%) female tibias, cones could not be positioned without breaching. No breaches were found in 22/49 (45.0%) male and 5/46 (10.9%) female tibias. For every 1 centimeter increase in patient height, odds of breaching decreased by 12% (odds ratio: 0.88, confidence interval: 0.84, 0.92). For every size increase in cone width, odds of breaching increased by 34% (odds ratio: 1.34, confidence interval: 1.28, 1.47). Placing cones deeper also increased breaching compared to the 1 mm cut.
In revision total knee arthroplasty, smaller OTS or custom tibial cones may be needed to fit a patient's proximal tibial geometry. This is especially true in patients not accommodated by the OTS cone sizes we tested, which impacted shorter patients and/or those with substantial bone loss requiring more tibial resection and deeper cone placement. Use of smaller or custom tibial cones should be considered where indicated.
在全膝关节置换翻修术中，胫骨锥已显示出更长的使用寿命和更低的无菌性松动发生率。目前几种现有的“现货供应”（OTS）锥系统可能没有适合所有患者骨骼形态的尺寸。
获取了100例初次全膝关节置换患者的计算机断层扫描图像以及4种OTS锥的尺寸。将压配柄置于三维胫骨模型中以适应骨干轨迹。在距胫骨内侧平台沟测量的1、6和13毫米截骨处，将锥体围绕柄放置，模拟胫骨近端截骨和骨质流失。在模拟锥体准备后检查胫骨是否有皮质骨穿孔。
随着锥体尺寸和深度的增加，穿孔率升高。在2/49（4.1%）的男性和19/46（41.3%）的女性胫骨中，不发生穿孔就无法放置锥体。在22/49（45.0%）的男性和5/46（10.9%）的女性胫骨中未发现穿孔。患者身高每增加1厘米，穿孔几率降低12%（优势比：0.88，置信区间：0.84，0.92）。锥体宽度每增加一个尺寸，穿孔几率增加34%（优势比：1.34，置信区间：1.28，1.47）。与1毫米截骨相比，将锥体放置得更深也会增加穿孔情况。
在全膝关节置换翻修术中，可能需要更小的OTS或定制胫骨锥以适应患者的胫骨近端几何形状。对于我们测试的OTS锥尺寸无法适应的患者尤其如此，这些患者包括身材较矮的患者和/或那些有大量骨质流失需要更多胫骨截骨和更深锥体放置的患者。在有指征的情况下应考虑使用更小的或定制的胫骨锥。
