1Institute for Medical Technology, Ostbayerische Technische Hochschule (OTH) Amberg-Weiden, Weiden, Germany.
2Hospital of Trauma Surgery, Department of musculoskeletal research, Marktredwitz Hospital, Marktredwitz, Germany.
Georgian Med News. 2023 Feb(335):32-35.
The use of modular femoral stems in primary and revision arthroplasty of the hip has become popular within the last decade. On the other hand, modularity creates new potential problems like fretting, crevice and galvanic corrosion, component loosening, dissociation, and fracture of modular prostheses. Recently a problem of fracture of a locking screw in revision arthroplasty of the hip using the MRP Titan Stem (Peter Brehm GmbH, Weisendorf, 91085 Germany) appeared. The aim of this study is to evaluate the meaning of surface contamination in respect to fracture mechanism. The titanium nitrid coated locking screw M6 of the MRP Titan system was in vitro tested in several series. After experimental contamination (series 1-4) morse taper junction was fixed by the locking screw with a torque wrench: Series 1: The influence of contamination with dried blood was examined while screw M6 was put into pig's blood. Series 2: The influence of contamination with dried blood and biologic tissue was examined while screw M6 was covered with a pulpous mixture of pig's blood, pig's muscle, and pig's fat tissue. Series 3: The influence of contamination with dried blood and biologic tissue was examined while female thread was covered with a pulpous mixture of pig's blood, pig's muscle, and pig's fat tissue. Series 4: The influence of cleaning of the contaminated female component was examined while female thread contamination (with a pulpous mixture of pig's blood, pig's muscle, and pig's fat tissue) was cleaned with 50 ml saline solution. Comparing series 1 with series 4, series 2 with series 4 and series 3 with series 4 statistical analysis showed a significant reduction of fractures of screw M6 (p-values <0.01). To avoid fracture of the screw M6 of the MRP Titan System we recommend cleaning the inner thread of the morse taper junction with saline solution before junction is fixed with the screw and the torque wrench.
在过去十年中，模块化股骨柄在髋关节初次和翻修关节置换术中的应用变得越来越流行。另一方面，模块化设计带来了一些新的潜在问题，如微动、缝隙和电偶腐蚀、部件松动、分离和模块化假体断裂。最近，在使用 MRP Titan 假体（德国 Peter Brehm 有限公司，Weisendorf，91085）进行髋关节翻修时，出现了锁定螺钉断裂的问题。本研究旨在评估表面污染对断裂机制的意义。体外对 MRP Titan 系统的氮化钛涂层锁定螺钉 M6 进行了多组测试。经过实验污染（第 1-4 组）后，莫氏锥度连接通过扭矩扳手固定锁定螺钉：第 1 组：在螺钉 M6 放入猪血时，检查干燥血液污染的影响。第 2 组：在螺钉 M6 被猪血、猪肌肉和猪脂肪组织的混合糊状物覆盖时，检查干燥血液和生物组织污染的影响。第 3 组：在女性螺纹被猪血、猪肌肉和猪脂肪组织的混合糊状物覆盖时，检查干燥血液和生物组织污染的影响。第 4 组：当女性螺纹（猪血、猪肌肉和猪脂肪组织的混合糊状物）污染时，检查用 50ml 生理盐水清洗污染的女性部件的影响。将第 1 组与第 4 组、第 2 组与第 4 组和第 3 组与第 4 组进行比较，统计分析显示螺钉 M6 断裂显著减少（p 值<0.01）。为避免 MRP Titan 系统螺钉 M6 断裂，我们建议在使用螺钉和扭矩扳手固定莫氏锥度连接之前，用生理盐水清洗莫氏锥度连接的内螺纹。
