Background

Although an additional internal bracing significantly increases stability in a repair of the lateral ulnar collateral ligament, it remains unclear whether it also does in reconstruction. Aim of this study was to implement a three-dimensional elbow simulator for testing posterolateral rotatory instability. We hypothesized that (1) reconstruction with and without internal bracing is comparable in biomechanical properties, and (2) there would be higher load-to-failure with internal bracing.

Methods

Posterolateral rotatory instability was tested by imitating the lateral pivot shift test in 16 elbows. Valgus and supination torques were simultaneously increased stepwise up to 1.2 Nm. Specimens were tested at 30°, 60°, 90°, and 120° elbow flexion with an intact lateral collateral ligament complex, dissected complex, and after reconstruction with or without internal bracing. Outcome measures included joint gapping, laxity, and load to failure.

Findings

With the implemented elbow simulator no significant difference was observed for gapping or laxity between both treatment groups. Comparing treatment and native ligament, gapping was reduced, especially with increased elbow flexion. Laxity was also reduced at some flexion angles. The mean load-to-failure was 8.1 ± 2.7 Nm without and 9.6 ± 3.6 Nm with internal bracing (P = 0.645).

Interpretation

Both treatments were comparable in biomechanical properties but did not fully restore the native state. Although the additional augmentation of the LUCL reconstruction tends to increase the maximum load to failure, this difference was not statistically significant. Still, reconstruction with internal bracing seems to be a reasonable option in selected primary reconstructions. It could also be useful in revision reconstruction.

中文翻译：

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使用三维肘部模拟器在有或没有其他内部支撑的情况下外侧副韧带重建的生物力学比较

背景

尽管额外的内部支撑明显增加了尺侧副韧带修复的稳定性，但仍不清楚在重建中是否也如此。这项研究的目的是实现一个三维肘模拟器来测试后外侧旋转不稳定性。我们假设（1）有内部支撑和不具有内部支撑的重建在生物力学特性上是可比的，并且（2）内部支撑会导致更高的破坏失败率。

方法

通过模仿16个肘部的侧向枢轴位移测试，测试了后外侧旋转不稳定性。外翻扭矩和旋后扭矩同时逐步增加至1.2 Nm。在完整的外侧副韧带复合体，解剖复合体以及重建后有无内部支撑的情况下，分别在30°，60°，90°和120°肘屈曲度下测试样本。结果指标包括关节间隙，松弛和破坏负荷。

发现

使用实施的肘部模拟器，两个治疗组之间的间隙或松弛度均未观察到明显差异。与治疗和天然韧带相比，间隙减少了，尤其是肘关节屈曲增加。在某些屈曲角度，松弛度也降低了。在没有内部支撑的情况下，平均故障载荷为8.1±2.7 Nm，在内部支撑下为9.6±3.6 Nm（P  = 0.645）。

解释

两种处理的生物力学性能均相当，但不能完全恢复其原始状态。尽管对LUCL重建的额外增加往往会增加最大的破坏负荷，但这种差异在统计学上并不显着。尽管如此，在选定的主要重建中，内部支撑重建似乎是一个合理的选择。在修订版本中也可能有用。