Department of Pediatric Orthopedics, Orthopedic Hospital Speising, Vienna, Austria.
Vienna Bone and Growth Center, European Reference Network Center for Rare Bone Diseases, Vienna, Austria.
Front Endocrinol (Lausanne). 2024 Sep 19;15:1422356. doi: 10.3389/fendo.2024.1422356. eCollection 2024.
X-linked hypophosphatemia (XLH) is a rare monogenetic skeletal disorder. Lower limb deformities contribute substantially to impaired gait quality and burden of disease in patients with XLH. Standardized data regarding onset and severity of lower limb maltorsion are unavailable. This study aimed to evaluate lower limb maltorsion using rotational magnetic resonance imaging (MRI) and computed tomography (CT).
Rotational MRI and CT of children and adolescents with verified XLH were evaluated retrospectively. Femoral and tibial torsion, acetabular anteversion, and axial acetabular coverage were measured and compared with published age-adapted radiographic, clinical measurements and MRI data, respectively.
Fifteen patients (mean age, 10.7 years) were included in the study. Decreased femoral torsion was observed in 47% (14/30 femora) and femoral retrotorsion in 17% (5/30 femora). Ten of 13 hips with coxa vara deformity presented with decreased femoral antetorsion. Reduced external tibial torsion manifested in 64% (18/28 tibiae). Abnormal axial femoral head coverage was present in 67% (20/30 hips), whereas 53% (16/30 hips) showed increased acetabular anteversion.
Femoral and tibial torsional pathologies were found in children and adolescents with XLH. The occurrence of severe femoral retrotorsion in a 2-year-old child prior to ambulation raises questions regarding the biomechanical impact of gait on the development of torsional deformities in XLH.
X 连锁低磷血症（XLH）是一种罕见的单基因骨骼疾病。下肢畸形严重影响 XLH 患者的步态质量和疾病负担。目前尚无关于下肢扭转畸形的发病和严重程度的标准化数据。本研究旨在使用旋转磁共振成像（MRI）和计算机断层扫描（CT）评估下肢扭转。
回顾性评估经证实的 XLH 儿童和青少年的旋转 MRI 和 CT。测量股骨和胫骨扭转、髋臼前倾角和轴向髋臼覆盖，并分别与已发表的年龄适应性影像学、临床测量和 MRI 数据进行比较。
本研究纳入 15 例患者（平均年龄 10.7 岁）。47%（30 个股骨中的 14 个）的股骨扭转减少，17%（30 个股骨中的 5 个）的股骨后旋。13 个髋部伴有髋内翻畸形的髋关节中，有 10 个表现为股骨内旋减少。64%（28 个胫骨中的 18 个）的胫骨外旋减少。67%（30 个髋关节中的 20 个）的股骨轴向股骨头覆盖异常，而 53%（30 个髋关节中的 16 个）的髋臼前倾角增加。
在 XLH 儿童和青少年中发现了股骨和胫骨扭转病理。在开始行走之前，一个 2 岁的孩子出现严重的股骨后旋，这引发了关于步态对 XLH 扭转畸形发展的生物力学影响的问题。
