Evaluation of the labrum on postoperative magnetic resonance images: a predictor of acetabular development in developmental dysplasia of the hip

Abstract

Introduction: Residual acetabular dysplasia of the hip after open reduction can complicate the treatment of developmental dysplasia of the hip (DDH) due to the potential need for corrective surgery. This retrospective study aimed to determine the predictive factors for acetabular development using postoperative radiographs and magnetic resonance imaging (MRI). Methods: We retrospectively investigated 74 hips of patients with DDH who underwent open reduction after reaching walking age and were followed up radiologically until skeletal maturity. We evaluated the cartilaginous acetabulum and labrum using a new method that measures the cartilaginous and labral landmarks on coronal and axial MR T2*-weighted images in patients aged 5 years. The mean age at the time of surgery was 22 months and that at the final survey was 20 years. Severin classification was determined at the final follow-up. Groups with good (53 hips) and poor (21 hips) outcomes were compared using the postoperative radiographic and MRI parameters recorded at 5 years of age. Factors predicting acetabular development were identified using univariate and multiple logistic analyses. Results: There were no significant differences in the bony-acetabular index (AI) and centre-edge (CE) angle between the good and poor outcome groups. However, the poor outcome group had significantly larger cartilaginous- and labral-AIs but significantly smaller cartilaginous- and labral-CE angles than the good outcome group (both p < 0.05). Multiple logistic regression analysis showed that labral-AI and labral-CE angle were predictors of acetabular development after open reduction for DDH, and their optimal cut-offs were 4° (77% sensitivity, 76% specificity) and 37° (68% sensitivity, 85% specificity), respectively. Discussion: Normal cartilaginous acetabulum development occurs in childhood, and evaluation using only radiographs is difficult. However, labral-AI ⩾4° and labral-CE angle <37° on MRI at 5 years of age offer useful indications for corrective surgery in patients with DDH.

Evaluation of Anterior Coverage in Children With Developmental Dysplasia of the Hip Using Transverse Magnetic Resonance Imaging at 2 Years Is Predictive of Future Radiographic Coverage

“…Some authors have reported cartilage morphology evaluation within the sagittal plane 23 and the labrum morphology of MRI. 11 In addition to these findings, we showed that evaluation of cartilaginous acetabular coverage in the transverse plane was also useful in predicting acetabular development. It should be noted that there are risks associated with performing MRI in infants in need of sedation and these may include respiratory failure and aspiration.…”

“…In one report that examined anteroposterior acetabular coverage using transverse MRI and acetabular development in childhood,11 the parameters of acetabular coverage evaluated in the transverse plane of MRI were not associated with subsequent acetabular development. The authors of that study measured the anterior and posterior acetabular index, which were evaluated only based on the morphology of the acetabulum, similar to the conventional acetabular index29 on plain radiographs.…”

Cartilaginous predictors of residual acetabular dysplasia (RAD) in developmental dysplasia of the hip following closed or open reduction: A systematic review and meta-analysis

“…And 4 of them were not available for full text, 17 studies did not match the subject, and 9 studies could not extract the 2 × 2 contingency table. Finally, 9 studies were included for qualitative synthesis ( 18 , 27 – 34 ) and 6 studies for quantitative synthesis ( 18 , 28 , 29 , 31 , 33 , 34 ). The search process and results are shown in Figure 2 .…”

“…The information from the 6 quantitatively synthesized studies is shown in Table 2 . Among them, there were 4 studies in the CAI group ( 18 , 28 , 31 , 34 ) and 4 studies in the CCE group ( 18 , 28 , 29 , 33 ).…”

“…First of all, CAI and CCE can be measured by MRI or arthrography, which are two different imaging methods. Secondly, from the perspective of the anatomical structure of the acetabulum, some studies have only measured the angle of the cartilage part, that is, CAI and CCE ( 18 , 29 , 31 , 34 ); other studies on the measurement of the angle include both the cartilage part and the labrum part, named L-AI and L-CEA ( 28 , 33 ) ( Figure 1 ). Although the two methods have different angles, they belong to the same type of measurement in principle, so we merge them into the same group and redefine them as the CAI group and CCE group.…”