A modified non-contrast MRI in the preoperative examination of periacetabular osteotomy at 3.0T.

Abstract

Purpose: To investigate whether the modified hip non-contrast magnetic resonance imaging (MRI) can replace the direct MRI hip arthrography (d-MRA) at 3.0T in developmental dysplasia of the hip (DDH) patients undergoing periacetabular osteotomy (PAO) preoperative examination, and also to assess the difference between these two methods.

Materials and methods: This retrospective study involved 35 patients (38 hips) with DDH who underwent periacetabular osteotomy, age 9-41 years old (mean age 25), 4 males (4 hips) and 34 females (34 hips). Each patient underwent both d-MRA and modified 3.0T non-contrast MRI examination of the hip joint. All patients underwent hip-preserving PAO surgery subsequently. Statistical analyses were performed to compare the joint injury examined by the two imaging methods.

Results: The modified non-contrast MRI detected the labral injury with a sensitivity of 94%, a specificity of 75%, an accuracy of 92%, and a positive predictive value of 97%. Among the 38 hips, 10 hips had labral varus (i.e., inward deviation or angulation of the acetabular labrum) with an incidence rate of 26% (10/38), 9 hips had acetabular cysts (i.e., the fluid-filled sacs that develop in or around the acetabulum, the socket of the hip joint) with an incidence rate of 23% (9/38). One patient had both the labral cyst and acetabular cartilage injury, and two patients had labral cyst only (overall incidence rate of labral cyst 7% (3/38)). The results were comparable to those of d-MRA in the examination of cartilage injury, labral varus, acetabular cyst, and labral cyst.

Conclusion: For preoperative hip-preserving surgery in DDH patients, the modified non-contrast MRI performed similarly to the d-MRA at 3.0T in diagnostic capabilities. The labral injury mostly occurs in the anterior upper quadrant.