Wakabayashi Kenjiro, Wada Ikuo, Horiuchi Osamu, Mizutani Jun, Tsuchiya Daiji, Otsuka Takanobu
Department of Orthopaedic Surgery, Nagoya City University, Graduate School of Medical Sciences, Nagoya, Japan.
J Pediatr Orthop. 2011 Jun;31(4):381-7. doi: 10.1097/BPO.0b013e31821a556e.
Residual subluxation of the hip is a major problem in pediatric orthopaedics. Corrective surgery by Salter innominate osteotomy is performed for residual subluxation before school age. Common indications for corrective surgery are determined based on the clinical condition, x-ray images, and arthrographic images. However, the surgical indications vary among institutions. Thus, further information that can predict acetabular growth with certainty is needed for precise decision- making. This study focused on signal intensity changes on magnetic resonance (MR) images within the weight-bearing portion of the acetabulum to determine whether these signal intensity changes could predict acetabular growth.
Thirty-six patients who showed residual subluxation after reduction of developmental dysplasia of the hip and whose MRIs were taken when they were around 3 years old were studied. Corrective surgery was performed in 14 patients, whereas the remaining 22 patients were followed conservatively. The presence of a high-signal intensity area (HSIA) within the weight-bearing portion of the acetabular cartilage on T2-weighted MR coronal section images was investigated, and the correlation between HSIA presence and acetabular growth was examined.
All patients who underwent corrective surgery showed an HSIA within the weight-bearing portion of the acetabular cartilage on T2-weighted MR images before surgery. After surgery, all patients showed HSIA disappearance or decrease. In patients who were followed conservatively, HSIA-positive patients had poor acetabular growth, whereas HSIA-negative patients had favorable acetabular growth.
HSIAs in the acetabular cartilage may be caused by an extraordinary stress load from the femoral head. The presence of HSIA on MRI may prevent acetabular growth. HSIA on MRI appears to be a significant decision-making tool for corrective surgery.
髋关节残留半脱位是小儿骨科的一个主要问题。对于学龄前期的髋关节残留半脱位，需行萨尔特骨盆截骨术进行矫正手术。矫正手术的常见适应证是根据临床情况、X线影像和关节造影影像来确定的。然而，各机构的手术适应证存在差异。因此，需要更多能够准确预测髋臼生长的信息以进行精确决策。本研究聚焦于髋臼负重部分磁共振（MR）图像上的信号强度变化，以确定这些信号强度变化是否能够预测髋臼生长。
对36例髋关节发育不良复位后仍存在残留半脱位且在3岁左右时进行了MRI检查的患者进行研究。14例患者接受了矫正手术，其余22例患者进行保守随访。研究T2加权MR冠状面图像上髋臼软骨负重部分高信号强度区域（HSIA）的存在情况，并检查HSIA的存在与髋臼生长之间的相关性。
所有接受矫正手术的患者在术前T2加权MR图像上髋臼软骨负重部分均显示有HSIA。术后，所有患者的HSIA均消失或减弱。在保守随访的患者中，HSIA阳性患者的髋臼生长较差，而HSIA阴性患者的髋臼生长良好。
髋臼软骨中的HSIA可能是由股骨头异常应力负荷所致。MRI上HSIA的存在可能会阻碍髋臼生长。MRI上的HSIA似乎是矫正手术的一个重要决策工具。
