Vercio Robert C, Anderson Mark, Thomas Alexander, Inceoglu Serkan, Wongworawat Montri Daniel
Department of Orthopaedic Surgery, Loma Linda University Health, Loma Linda, CA.
Department of Orthopaedic Surgery, Loma Linda University Health, Loma Linda, CA.
J Hand Surg Am. 2018 Dec;43(12):1081-1084. doi: 10.1016/j.jhsa.2018.09.005. Epub 2018 Oct 24.
To evaluate if redirecting a Kirschner wire (K-wire) through the same proximal hole will weaken the pull-out force and to test if multiple redirections will result in a continued stepwise decrease in pull-out force.
An Instron was used to test the pull-out force of K-wires using the peak initial failure load as a measure of failure of K-wire fixation. K-wires 0.062 inches in diameter were inserted with an angled drill guide into a bicortical bone substrate. Trials were divided into 7 groups with the first group having the K-wires placed through both cortices and then tested without redirection. In groups 2-6, the K-wire was placed bicortically and then withdrawn and redirected through the same proximal hole with 1, 2, 3, 4, and 5 redirections. A control group in which the K-wire was only unicortical was also tested.
Compared with the control group of no redirects, any number of redirections weakened the pull-out force. There was no difference between redirected groups and the unicortical group. When comparing between redirections, there were no significant differences in pull-out force. Regression analysis showed that, after the first redirection, there was no stepwise change in pull-out force with additional redirection.
There was a significant decrease in pull-out force with any redirections, but there was no stepwise decrease in failure force after multiple redirections. The failure force of any redirection was similar to a unicortically placed wire.
Any K-wire redirection attempts in hand bone fixation can result in a considerably weakened construct.
评估将克氏针（K 针）通过同一个近端孔重新插入是否会削弱拔出力，并测试多次重新插入是否会导致拔出力持续逐步下降。
使用英斯特朗万能材料试验机，以初始峰值破坏载荷作为 K 针固定失败的衡量指标，测试 K 针的拔出力。将直径为 0.062 英寸的 K 针通过成角钻孔导向器插入双皮质骨基质中。试验分为 7 组，第一组将 K 针穿过两层皮质，然后不进行重新插入直接测试。在第 2 - 6 组中，K 针双皮质插入后拔出，再通过同一个近端孔重新插入，分别进行 1、2、3、4 和 5 次重新插入。还测试了一个仅单皮质插入 K 针的对照组。
与不重新插入的对照组相比，任何次数的重新插入都会削弱拔出力。重新插入组与单皮质组之间没有差异。在不同次数重新插入之间进行比较时，拔出力没有显著差异。回归分析表明，在第一次重新插入后，随着额外的重新插入，拔出力没有逐步变化。
任何重新插入都会使拔出力显著降低，但多次重新插入后破坏力不会逐步下降。任何重新插入的破坏力与单皮质放置的钢丝相似。
在手骨固定中任何 K 针重新插入的尝试都可能导致结构显著变弱。
