软骨发育不全患者的胫骨坡度：其特征及在膝反屈发展中的可能作用。

The Tibial Slope in Patients With Achondroplasia: Its Characterization and Possible Role in Genu Recurvatum Development.

作者信息

Brooks Jaysson T, Bernholt David L, Tran Kevin V, Ain Michael C

机构信息

*Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, MD †Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, MO.

出版信息

J Pediatr Orthop. 2016 Jun;36(4):349-54. doi: 10.1097/BPO.0000000000000458.

DOI:10.1097/BPO.0000000000000458

PMID:26114241

Abstract

BACKGROUND

Genu recurvatum, a posterior resting position of the knee, is a common lower extremity deformity in patients with achondroplasia and has been thought to be secondary to ligamentous laxity. To the best of our knowledge, the role of the tibial slope has not been investigated, and no studies describe the tibial slope in patients with achondroplasia. Our goals were to characterize the tibial slope in children and adults with achondroplasia, explore its possible role in the development of genu recurvatum, and compare the tibial slope in patients with achondroplasia to that in the general population.

METHODS

We reviewed 252 lateral knee radiographs of 130 patients with achondroplasia seen at our clinic from November 2007 through September 2013. Patients were excluded if they had previous lower extremity surgery or radiographs with extreme rotation. We analyzed patient demographics and, on all radiographs, the tibial slope. We then compared the mean tibial slope to norms in the literature. Tibial slopes >90 degrees had an anterior tibial slope and received a positive prefix. Statistical analysis included intraclass and interclass reliability, Pearson correlation coefficient, and the Student t tests (significance, P<0.05).

RESULTS

The overall mean tibial slope for the 252 knees was +1.32±7 degrees, which was significantly more anterior than the normal slopes reported in the literature for adults (7.2 to 10.7 degrees, P=0.0001) and children (10 to 11 degrees, P=0.0001). The Pearson correlation coefficient for mean tibial slope and age showed negative correlations of -0.4011 and -0.4335 for left and right knees, respectively. This anterior tibial slope produces proximal and posterior vector force components, which may shift the knee posteriorly in weightbearing.

CONCLUSIONS

The mean tibial slope is significantly more anterior in patients with achondroplasia than in the general population; however, this difference diminishes as patients' age. An anterior tibial slope may predispose to a more posterior resting knee position, also known as genu recurvatum.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

摘要

背景

膝反屈，即膝关节的后位休息姿势，是软骨发育不全患者常见的下肢畸形，一直被认为是韧带松弛的继发结果。据我们所知，胫骨坡度的作用尚未得到研究，也没有研究描述软骨发育不全患者的胫骨坡度。我们的目标是描述软骨发育不全儿童和成人的胫骨坡度，探讨其在膝反屈发展中的可能作用，并比较软骨发育不全患者与普通人群的胫骨坡度。

方法

我们回顾了2007年11月至2013年9月在我们诊所就诊的130例软骨发育不全患者的252张膝关节侧位X线片。如果患者既往有下肢手术史或X线片有极端旋转情况，则将其排除。我们分析了患者的人口统计学数据，并在所有X线片上测量了胫骨坡度。然后，我们将平均胫骨坡度与文献中的标准值进行比较。胫骨坡度>90度为胫骨前坡度，并给予正前缀。统计分析包括组内和组间可靠性、Pearson相关系数以及Student t检验（显著性，P<0.05）。

结果

252个膝关节的总体平均胫骨坡度为+1.32±7度，明显比文献中报道的成人正常坡度（7.2至10.7度，P=0.0001）和儿童正常坡度（10至11度，P=0.0001）更靠前。平均胫骨坡度与年龄的Pearson相关系数显示，左膝和右膝分别为-0.4011和-0.4335，呈负相关。这种胫骨前坡度会产生近端和后向矢量力分量，在负重时可能会使膝关节向后移位。