Purpose

Early-onset degeneration of the knee is linked to genetics, overload, injury, and potentially, knee morphology. The purpose of this study is to explore the characteristics of the small medial femoral condyle, as a distinct knee morphotype, by means of a landmark-based three-dimensional (3D) analysis and statistical parametric mapping.

Methods

Sixteen knees with a small medial femoral condyle (SMC) were selected from a database of patients with distinct knee joint anatomy and 16 gender-matched knees were selected from a control group database. 3D models were generated from the medical imaging. After normalization for size, a set of pre-defined landmark-based parameters was analysed for the femur and tibia. Local shape differences were evaluated by matching all bone surfaces onto each other and comparing the distances to the mean control group bone shape.

Results

The small medial condyle group showed a significant association with medial compartment degeneration and had a 4% and 13% smaller medial condyle anteroposteriorly and mediolaterally, whereas the distal femur was 3% wider mediolaterally. The lateral condyle was 2% smaller anteroposteriorly and 8% wider mediolaterally. The complete tibial plateau was 3% smaller mediolaterally and the medial tibial plateau was 6% smaller.

Conclusion

A new knee morphotype demonstrated an increased risk for medial compartment degeneration and was differentiated from a healthy control group based on the following morphological characteristics: a smaller medial femoral condyle and medial tibial plateau, a wider lateral femoral condyle and a wider distal femur on a smaller tibial plateau. This pilot study suggests a role for the SMC knee morphotype in the multifactorial process of medial compartment degeneration.

Level of evidence

III

中文翻译：

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较小的股内侧con形态与内侧区室变性和独特的形态特征有关：一项比较性的初步研究。

目的

膝关节的早期发病与遗传，超负荷，损伤以及潜在的膝关节形态有关。这项研究的目的是通过基于地标的三维（3D）分析和统计参数映射来探讨股内侧小con的特征，即独特的膝关节形态。

方法

从膝关节解剖结构不同的患者数据库中选择16个带有小内侧media骨（SMC）的膝盖，并从对照组数据库中选择16个性别匹配的膝盖。从医学成像生成3D模型。尺寸标准化后，分析了一组针对股骨和胫骨的基于界标的预定义参数。通过将所有骨骼表面彼此匹配并将距离与平均对照组骨骼形状进行比较来评估局部形状差异。

结果

小内侧con组与内侧腔室变性显着相关，并且前后and内侧和内侧偏小，内侧smaller分别缩小4％和13％，而股骨远端内侧偏宽3％。外侧con的前部小2％，内侧小8％。完整的胫骨平台内侧变小3％，内侧胫骨平台缩小6％。

结论

一种新的膝关节形态表现出增加的内侧隔室变性风险，并根据以下形态特征与健康对照组进行了区别：较小的内侧股骨con和胫骨内侧平台，较大的外侧股骨lateral和较宽的股骨远端，较小胫骨平台 这项初步研究表明，SMC膝关节形态在内侧腔室变性的多因素过程中发挥了作用。

证据水平

三级