Tanaka Atsuki, Hiranaka Takafumi, Fujishiro Takaaki, Koide Motoki, Suda Yoshihito, Saito Akira, Arimoto Akihiko, Okamoto Koji
Department of Orthopaedic Surgery and Joint Surgery Centre, Takatsuki General Hospital, Takatsuki, JPN.
Cureus. 2023 Jul 4;15(7):e41349. doi: 10.7759/cureus.41349. eCollection 2023 Jul.
Background For successful internal fixation for femoral neck fracture, the sliding mechanism of the screw is important because it can induce inter-fragmental compression. The thread should penetrate the fracture line and be located within the proximal fragment. If screw thread engagement is incomplete and a part of the thread remains within the distal fragment, the screw sliding can be disturbed, potentially leading to fixation failure. We hypothesized that screw thread in the fracture is a risk of fixation failure. Methods We studied 133 hips that underwent internal fixation for femoral neck fracture using dual sliding and compression screws (DSCS) with 20 mm threads. The existence of incomplete thread engagement and fixation failure (cut out, perforation, pseudoarthrosis, or femoral neck shortening) were evaluated on anteroposterior hip radiography postoperatively. The distances from the thread end to the fracture line, screw head to the femoral head cortex, and femoral head diameter were measured to analyze their relationships with any incomplete thread engagement and fixation failure. Differences in evaluation data were assessed using Fisher's exact test, Student's t-test, and receiver operating characteristic (ROC) analysis. Results Forty-six cases had at least one screw with incomplete thread engagement, and the other 87 hips had a complete engagement. The failure rate in the group of hips with incomplete thread engagement was significantly higher (7/46, 15.2%) than that in the group of hips with complete thread engagement (3/87, 3.4%) ( = 0.032). Incomplete thread engagement was found in 59 out of 266 screws (22.2%), and a femoral head ≤ 43.9 mm in diameter was associated with an increased risk of incomplete thread engagement. Most incomplete thread engagement screws (81.4%) had < 5 mm thread length within the distal fragment. Conclusion A partially threaded screw is a significant risk of fixation failure after internal fixation for a femoral neck fracture. The smaller femoral head diameter increases the possibility of incomplete thread engagement. Shortening the thread length by 5 mm may help to avoid incomplete thread engagement.
背景 对于股骨颈骨折的成功内固定而言，螺钉的滑动机制很重要，因为它可引起骨折块间的加压。螺纹应穿透骨折线并位于近端骨折块内。如果螺钉螺纹啮合不完全且部分螺纹留在远端骨折块内，则螺钉滑动可能会受到干扰，从而可能导致固定失败。我们推测骨折处的螺钉螺纹是固定失败的一个风险因素。方法 我们研究了133例使用20毫米螺纹的双滑动加压螺钉（DSCS）进行股骨颈骨折内固定的髋关节。术后通过髋关节前后位X线片评估螺纹啮合不完全和固定失败（穿出、穿孔、假关节形成或股骨颈缩短）的情况。测量螺纹末端到骨折线的距离、螺钉头部到股骨头皮质的距离以及股骨头直径，以分析它们与螺纹啮合不完全和固定失败的关系。使用Fisher精确检验、Student t检验和受试者工作特征（ROC）分析评估评估数据的差异。结果 46例至少有一枚螺钉螺纹啮合不完全，另外87例髋关节螺纹啮合完全。螺纹啮合不完全组的失败率（7/46，15.2%）显著高于螺纹啮合完全组（3/87，3.4%）（P = 0.032）。266枚螺钉中有59枚（22.2%）螺纹啮合不完全，股骨头直径≤43.9毫米与螺纹啮合不完全的风险增加相关。大多数螺纹啮合不完全的螺钉（81.4%）在远端骨折块内的螺纹长度<5毫米。结论 部分螺纹的螺钉是股骨颈骨折内固定后固定失败的一个重要风险因素。较小的股骨头直径增加了螺纹啮合不完全的可能性。将螺纹长度缩短5毫米可能有助于避免螺纹啮合不完全。
