Background

Patellofemoral instability is a debilitating condition mainly affecting young patients and has been correlated with trochlear dysplasia. It can occur when the patella is insufficiently guided through its range of motion. Currently, there is no literature describing patellofemoral stability in trochleodysplastic knees and the effect of isolated trochleoplasty on patellofemoral stability.

Methods

The effect of isolated trochleoplasty in trochleodysplastic knees of patients with symptomatic patellofemoral instability was investigated using a quasi-static finite element model. MRI data of five healthy knees were segmented, meshed and a finite element analysis was performed in order to validate the model. A second validation was performed by comparing simulated patellofemoral kinematics to in-vivo values obtained from upright- weight bearing CT scans. Subsequently, five trochleodysplastic knees were modelled before and after simulated trochleoplasty. The force necessary to dislocate the patella by 10 mm and to fully dislocate the patella was calculated in various knee flexion angles between 0 and 45°.

Findings

The developed models successfully predicted outcome values within the range of reference values from literature. Lateral stability was significantly lower in trochleodysplastic knees compared to healthy knees. Trochleoplasty was determined to significantly increase the force necessary to dislocate the patella in trochleodysplastic knees to comparable values as in healthy knees.

Interpretation

This is the first study to investigate lateral patellofemoral stability in patients with symptomatic patellofemoral instability and dysplasia of the trochlear groove. We confirm that patellofemoral stability is significantly lower in trochleodysplastic knees than in healthy knees. Trochleoplasty increases patellofemoral stability to levels similar to healthy.

中文翻译：

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滑行增生性增生性膝关节股不稳及模拟性滑车成形术的定量影响-有限元模拟

背景

ello股不稳定是一种令人衰弱的疾病，主要影响年轻患者，并与滑车发育不良有关。当the骨在其运动范围内受到不充分的引导时，会发生这种情况。目前，没有文献描述滑车增生性膝关节的pa股稳定和孤立的滑车成形术对pa股稳定的影响。

方法

使用拟静态有限元模型研究了孤立性滑车成形术对有症状的pa股不稳定患者的滑行增生性膝关节的影响。对五个健康膝盖的MRI数据进行分割，划分网格并进行有限元分析，以验证模型。通过比较模拟pa股运动学与从承受负重CT扫描获得的体内值进行第二次验证。随后，在模拟的滑车成形术前后，模拟了五个滑车增生性膝关节。在0到45°之间的各种膝盖屈曲角度中计算出使the骨移位10 mm和使dis骨完全移位所需的力。

发现

所开发的模型成功地预测了文献参考值范围内的结果值。与健康的膝盖相比，滑行增生性膝关节的侧向稳定性明显较低。经确定，滑车成形术可显着增加使滑车增生性膝关节s骨脱位所需的力，使其达到与健康膝关节相当的值。

解释

这是第一个研究有症状的tell股不稳和滑车沟发育不良的患者的pa股外侧稳定性的研究。我们证实，滑车增生性膝关节的em股稳定明显低于健康膝关节。滑车成形术将pa股稳定增加到与健康相似的水平。