Objective

Focal lesions within the subchondral bone, termed subchondral bone cysts (SBCs), are clinically accepted radiographic markers of advanced osteoarthritis (OA), but their etiology in the hip is not well understood.

Design

This study used micro-computed tomography (μCT), and histological and immunocytological analysis to examine the prevalence, size, location, and morphological and cellular features of SBCs found within 34 femoral heads (14 male, 20 female; age range = 43–80 years) obtained from total hip arthroplasty procedures.

Results

SBCs were common—present in 91% of the femoral heads examined—and frequently commuted with the surface of the femoral head, but otherwise showed no preferred anatomical location. Few associations were found between SBC features and patient characteristics such as BMI, age and sex. SBCs were also heterogenous in composition, ranging from fibrous (most common) to predominantly fatty (least common) and often containing vasculature, nerve fibers, cartilage islands, and bony spicules. Despite this heterogeneity, focal abnormalities in bone density and cartilage thickness were consistently observed. Bone adjacent to SBCs was denser than that in the primary compressive group, and cartilage thickness in regions overlying SBCs was lower than in non-overlying regions. In contrast to these local bony changes, μCT-based finite element analyses indicated that the stiffness of the primary compressive group was only mildly affected by SBCs.

Conclusions

These findings indicate that SBCs in the femoral head involve extensive perturbations in cellular activity, culminating in myriad skeletal tissue types and spatially heterogenous changes in bone and cartilage morphology that are likely to affect OA progression.

中文翻译：

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髋骨关节炎软骨下骨囊肿及邻近组织的结构特征

客观的

软骨下骨内的局灶性病变，称为软骨下骨囊肿 (SBC)，是临床上公认的晚期骨关节炎 (OA) 的放射学标志物，但其在髋部的病因尚不清楚。

设计

本研究使用微计算机断层扫描 (μCT) 以及组织学和免疫细胞学分析来检查 34 个股骨头（14 名男性，20 名女性；年龄范围 = 43-80 岁）内发现的 SBC 的患病率、大小、位置以及形态和细胞特征。年）从全髋关节置换术中获得。

结果

SBC 很常见——存在于 91% 的检查股骨头中——并且经常与股骨头表面交换，但除此之外没有显示出首选的解剖位置。SBC 特征与患者特征（如 BMI、年龄和性别）之间几乎没有发现关联。SBC 的成分也多种多样，从纤维性（最常见）到以脂肪为主（最不常见），通常含有脉管系统、神经纤维、软骨岛和骨针。尽管存在这种异质性，但仍观察到骨密度和软骨厚度的局部异常。与 SBC 相邻的骨密度比初次压缩组的骨质更密，并且 SBC 上方区域的软骨厚度低于非上方​​区域的软骨厚度。与这些局部骨变化相反，基于 μCT 的有限元分析表明，主要压缩组的刚度仅受到 SBC 的轻微影响。

结论

这些发现表明，股骨头中的 SBC 涉及细胞活动的广泛扰动，最终导致多种骨骼组织类型以及骨和软骨形态的空间异质变化，这些变化可能会影响 OA 的进展。