Wang Zhigang, Xu Yunlan, Jiang Enze, Wang Jianmin, Tomatsu Shunji, Shen Kaiying
Department of Pediatric Orthopedics, Shanghai Children's Medical Center affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China.
Department of Hematology/Oncology, Shanghai Children's Medical Center affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China.
Diagnostics (Basel). 2020 Apr 29;10(5):264. doi: 10.3390/diagnostics10050264.
Patients with mucopolysaccharidoses IVA (MPS IVA) have a progressive accumulation of the specific glycosaminoglycans (GAGs): chondroitin-6-sulfate (C6S) and keratan sulfate (KS), leading to the degeneration of the cartilage matrix and its connective tissue perturbing the regular microarchitecture of cartilage and successively distorting bone ossification and growth. Impaired cartilage quality and poor bone mineralization lead to serious hip disorders in MPS IVA patients. Although hip dysplasia is seen widely in musculoskeletal abnormality of this disorder, the pathophysiology of the hip bone and cartilage morphology in these patients remains unclear. Until now, no systemic study of the hip joints in MPS IVA has been reported by using the combined images of plain film radiographs (PFR) and Magnetic Resonance Imaging (MRI). This study aimed to assess the bony and cartilaginous features of hip joints and to explore the potentially related factors of femoral head osteonecrosis (FHN) and hip subluxation/dislocation in patients with MPS IVA. Hip joints in MPS IVA patients were retrospectively reviewed, based on the findings of PFR and MRI data from 2014 to 2019. Demographic information was also collected and analyzed with imaging measurements. A total of 19 patients (eight boys and 11 girls) were recruited, and 38 hip joints in these patients were examined. Eleven patients (57.9%) had FHN. FHN patients were statistically compared with those without FHN. Correlations between cartilaginous femoral head coverage (CFHC) and acetabular index (AI), cartilaginous AI (CAI), or neck-shaft angle (NSA) were investigated in patients with hip subluxation or dislocation. The greater cartilaginous coverage of the hips than their osseous inherency was observed. Significant correlation was observed between CFHC and AI (r =-0.351, = 0.049) or CAI (r =-0.381, = 0.032). Severe subluxations or dislocations were more likely to be present in those with more dysplastic bony and cartilaginous hips. In conclusion, our study provides the first systemic description of bony and cartilaginous characteristics in the hip morphology of MPS IVA patients. We have demonstrated that plain radiography alone leads to a misunderstanding of hip morphology and that MRI measurements with PFR are an essential tool to evaluate the 'true' characterization of hips for MPS IVA patients.
IVA型黏多糖贮积症（MPS IVA）患者体内特定糖胺聚糖（GAGs）——硫酸软骨素6-硫酸盐（C6S）和硫酸角质素（KS）会进行性蓄积，导致软骨基质及其结缔组织退变，扰乱软骨正常微结构，并相继扭曲骨化和生长。软骨质量受损和骨矿化不良导致MPS IVA患者出现严重的髋关节疾病。尽管髋关节发育不良在该疾病的肌肉骨骼异常中很常见，但这些患者髋骨和软骨形态的病理生理学仍不清楚。到目前为止，尚未有关于使用X线平片（PFR）和磁共振成像（MRI）联合图像对MPS IVA患者髋关节进行系统研究的报道。本研究旨在评估MPS IVA患者髋关节的骨和软骨特征，并探讨股骨头坏死（FHN）和髋关节半脱位/脱位的潜在相关因素。基于2014年至2019年的PFR和MRI数据结果，对MPS IVA患者的髋关节进行回顾性研究。还收集了人口统计学信息，并与影像学测量结果进行分析。共招募了19例患者（8名男性和11名女性），检查了这些患者的38个髋关节。11例患者（57.9%）患有FHN。对FHN患者与无FHN患者进行统计学比较。在髋关节半脱位或脱位患者中，研究软骨股骨头覆盖度（CFHC）与髋臼指数（AI）、软骨AI（CAI）或颈干角（NSA）之间的相关性。观察到髋关节的软骨覆盖度大于其骨性固有结构。观察到CFHC与AI（r = -0.351，P = 0.049）或CAI（r = -0.381，P = 0.032）之间存在显著相关性。在骨性和软骨性髋关节发育不良更严重的患者中，更易出现严重的半脱位或脱位。总之，我们的研究首次系统描述了MPS IVA患者髋部形态的骨和软骨特征。我们已经证明，仅靠X线平片会导致对髋部形态的误解，而PFR结合MRI测量是评估MPS IVA患者髋部“真实”特征的重要工具。
