Intra-articular dysplasia of the femoral head in developmental dysplasia of the hip

Morphological Changes and Concentricity of the Hip Joint During Gradual Reduction in Infants with Late-Detected Developmental Dysplasia of the Hip: A Retrospective Study

Background

The relationship between hip morphological changes and joint concentricity in infants with late-detected developmental dysplasia of the hip (DDH) treated with gradual reduction remains unclear. Therefore, we investigated hip morphological changes and concentricity in infants with late-detected unilateral DDH using magnetic resonance imaging (MRI) during gradual reduction.

Methods

We enrolled 20 infants aged ≥ 12 months with unilateral DDH. Treatment comprised continuous traction, a hip-spica cast, and an abduction brace. MRI was performed before treatment, immediately after hip-spica cast placement, after cast removal, and at the end of the brace. We evaluated the acetabulum and femoral head morphology and joint concentricity.

Results

The mean age was 25 months, and female sex and the left side were predominant. Before treatment, the acetabulum was small and shallow and the femoral head was spherically flat on the affected side. Immediately after the continuous traction, the affected acetabulum and femoral head were still smaller than the healthy/contralateral one. However, they improved to a deeper acetabulum and round femoral head. Intra-articular soft tissue (IAST) and femoral-acetabular distance (FAD) continuously decreased, indicating gradual improvement in joint concentricity. Deeper formation of the acetabulum and round shaping of the femoral head had occurred even in non-concentric reduction.

Conclusion

The shape and concentricity of the hip joint improved after treatment; however, the acetabulum and femoral head remained small. The deeper acetabulum and round femoral head were observed the non-concentric reduction before the concentric reduction was achieved. The continuous decrease in IAST and FAD indicates effective post-traction therapy.

Femoral Head Remodeling After Surgical Reduction of Developmental Hip Dislocations

OBJECTIVE

Developmental dysplasia of the hip is prevalent and is associated with dysplasia of both the femoral head and acetabulum. There is a paucity of literature describing femoral head remodeling after surgical reduction of developmentally dislocated hips. The purpose of this study was to describe and quantify changes in femoral head sphericity after closed or open reduction for developmental dysplasia of the hip.

METHODS

A retrospective cohort study was performed including patients with typical developmental hip dislocations who underwent closed or open reduction from 2009 to 2022 at a single institution and had immediate postoperative and average 3-week follow-up magnetic resonance imaging (MRI) scans. A subset of patients also had 3-year follow-up MRI scans. Patients with insufficient imaging or bony procedures at the time of reduction were excluded. We developed a technique to quantify femoral head "sphericity" by comparing differences in measured radii of the femoral head on axial and coronal plane MRI slices. We then calculated the variance of the radii for each plane and averaged these to calculate a combined variance. The variance was used to represent "sphericity," with a larger variance indicating a wider distribution of radii and thus a less spherical shape.

RESULTS

A total of 74 patients (69 females) with 96 hips were included in this series. The median age of the child at the time of reduction was 8.7 months [interquartile range (IQR): 2.2]. Over half (58.3%) of the hips had a closed reduction, whereas the remaining were open reduced (41.7%). Immediately postoperatively, at the 3-week time point, and at the 3-year time point the median combined variance was 1.1 (IQR: 3.93), 0.51 (IQR: 1.32), and 0.31 (IQR: 0.50), respectively, indicating improved sphericity over time.

CONCLUSIONS

Sphericity of the femoral head in developmental hip dislocations improves in both the immediate postoperative period, as well as the first few years after reduction. Further research is needed to evaluate the mechanism of remodeling, the ideal timing of reduction, and the relationship between femoral head and acetabular remodeling.

LEVEL OF EVIDENCE

Level IV-case series, therapeutic study.

Effect of hip dysplasia on the development of the femoral head growth plate

Purpose

The purpose of this study was to observe whether developmental dysplasia of the hip (DDH) affects the development of the femoral head growth plate and to analyze the risk factors.

Methods

We selected female patients aged between 11 and 20 years with unilateral DDH and unclosed femoral head growth plate (s). The selected patients underwent anteroposterior radiography of the hip joint to compare the degree of development of the femoral head growth plate on both sides and to identify risk factors that affect the development of the growth plate in the femoral head.

Results

We included 48 female patients with unilateral DDH, with an average age of 14 years (range: 11.1-18.5 years) and an average BMI of 20.4 kg/m² (range: 15.5 kg/m²-27.9 kg/m²). Among them, 23 patients had earlier development of the femoral head growth plate on the affected side than on the healthy side, while the degree of development of the femoral head growth plate in 25 patients was the same as that on the contralateral side. When the Tönnis angle was greater than 29.5°C and/or the Reimers migration index was greater than 48.5%, there was a statistically significant difference in the acceleration of femoral head growth plate development.

Conclusion

An abnormal relative position of the acetabulum-femoral head caused by DDH can accelerate closure of the femoral head growth plate in immature female patients. The risk factors are a Tönnis angle greater than 29.5°C and/or Reimers migration index greater than 48.5%.

Failure to achieve reduction on developmental dysplasia of hip: an ultrasound evaluation

BACKGROUND

Ultrasound examination of the medial side of the hip joint has been rarely used to evaluate the status of developmental dysplasia of the hip (DDH) in Pavlik harness treatment according to the literature.

PURPOSE

To analyze the effects of cartilaginous acetabulum, hip joint labrum, and acetabular tissue on the reduction of DDH.

MATERIAL AND METHODS

A total of 50 cases (100 hips) were detected by the Graf method with a high-frequency linear transducer (L 5-12), and there were 59 dislocated hips and 41 non-dislocated hips. Patients were treated with a Pavlik harness. Ultrasound examination of the medial side of the hip joint was performed for follow-up. The hip joints were divided into three groups: the non-dislocated group; the reducible group; and the non-reducible group.

RESULTS

The success rate of reduction was significantly higher when the acetabulum cartilage was located on the cephalic side (chi-square = 28.12, P < 0.001). The success rate was also significantly higher when the hip joint labrum was located on the cephalic side (chi-square = 17.21, P < 0.001). Type III and D had a higher success rate of reduction than type IV (P < 0.001). The pairwise comparison of the measurements of acetabular tissue between the non-dislocated group, the reducible group, and the non-reducible group showed statistical differences (P < 0.001).

CONCLUSION

The present study confirmed that the location of acetabulum cartilage and hip joint labrum affected the outcome of treatment. The degree of dislocation and the amount of acetabular tissue were correlated with the success rate of treatment.

3-D Ultrasound Imaging Reliability of Measuring Dysplasia Metrics in Infants

Developmental dysplasia of the hip is a hip abnormality that ranges from mild acetabular dysplasia to irreducible femoral head dislocations. While 2-D B-mode ultrasound (US)-based dysplasia metrics or disease metrics are currently used clinically to diagnose developmental dysplasia of the hip, such estimates suffer from high inter-exam variability. In this work, we propose and evaluate 3-D US-derived dysplasia metrics that are automatically computed and demonstrate that these automatically derived dysplasia metrics are considerably more reproducible. The key features of our automatic method are (i) a random forest-based learning technique to remove regions across the coronal axis that do not contain bone structures necessary for dysplasia-metric extraction, thereby reducing outliers; (ii) a bone segmentation method that uses rotation-invariant and intensity-invariant filters, thus remaining robust to signal dropout and varying bone morphology; (iii) a novel slice-based learning and 3-D reconstruction strategy to estimate a probability map of the hypoechoic femoral head in the US volume; and (iv) formulae for calculating the 3-D US-derived dysplasia metrics. We validate our proposed method on real clinical data acquired from 40 infant hip examinations. Results show a considerable (around 70%) reduction in variability in two key 3-D US-derived dysplasia metrics compared with their 2-D counterparts.

The radiological research for pelvis asymmetry of unilateral developmental dysplasia of the hip in adult

Objectives

To investigate whether adult patients with unilateral developmental dysplasia of the hip (UDDH) have pelvic asymmetry and what correlation existing between them.

Methods

A total of 100 adult patients with UDDH were enrolled in the retrospective observational study in Shanghai Jiaotong University Affiliated Sixth People’s Hospital, Shanghai, China, between January 2012 and February 2014. The anteroposterior pelvic radiographs were reviewed and the pelvic heights and ischium heights were measured and compared between the affected and non-affected sides to find out the relationship between the pelvic morphology and hip dysplasia.

Results

The pelvic heights demonstrated significant differences between the non-affected side and the affected side in patients with Crowe type II-IV UDDH (p<0.05), but not in patients with Crowe type I UDDH (p=0.09). There were significant differences in the bilateral ischium heights in patients with Crowe type III and IV UDDH (p<0.05), but not in patients with Crowe type I and II UDDH (p=0.78, p=0.055). In addition, the degree of hip dysplasia was positively associated with the degrees of asymmetry of pelvis (r=0.78, p<0.001) and ischium (r=0.72, p<0.001) in UDDH patients.

Conclusion

The pelvic asymmetry exists in adult patients with UDDH. In addition, the degree of asymmetry has correlation with the degree of hip dysplasia. We recommend that it should be taken more cautions to use teardrops and ischial tuberosity as anatomy landmarks to balance leg-length discrepancy for unilateral DDH patients in preoperative planning and total hip arthroplasty.