Variables influencing the pelvic radiological evaluation in children with developmental dysplasia of the hip managed by closed reduction: a multicentre investigation

Severity of hip dysplasia as the major factor affecting outcome of closed reduction in children with hip dysplasia

The objective of this study was to analyze a multicenter cohort of children with developmental dysplasia of the hip (DDH) who underwent treatment with closed reduction. We sought to report the effects that severity of hip dysplasia and age have on the development of femoral head avascular necrosis (AVN) and the need for additional procedures. All patients with DDH and minimum 2 years of follow-up who underwent closed reduction were identified. The following variables were recorded: sex, laterality of hip involvement, age, acetabular index (AI), and International Hip Dysplasia Institute (IHDI) grade. The effects of patient age and pre-procedure IHDI grade on the rate of AVN and need for additional procedures after the closed reduction were analyzed using an alpha of 0.05. Seventy-eight total hips were included in the final analysis. The average patient age was 12 months. AVN of the femoral head was reported in 24 hips (30.8%) and 32 hips (41.0%) required additional surgery. Higher pre-op IHDI grade was associated with higher risk of developing Bucholz-Ogden grades II-IV AVN of the femoral head ( P = 0.025) and requiring additional surgery ( P = 0.033) regardless of patient age. There were no statistically significant differences for the effect of age on the measured outcomes ( P  > 0.05). These findings suggest that severity of dislocation (IHDI grade) is a significant risk factor for the development of AVN and need for additional procedure.

Factors influencing outcomes of pelvic osteotomy for residual acetabular dysplasia following closed reduction in patients with developmental dysplasia of the hip

To investigate the factors influencing outcome of pelvic osteotomy (PO) for residual acetabular dysplasia (RAD) following closed reduction (CR) in patients with developmental dysplasia of the hip (DDH). We retrospectively reviewed 91 patients (95 hips) with DDH who underwent PO for RAD. Tönnis grade, Acetabular index, Center Edge Angle, Reimer's Index (RI), and avascular necrosis of the femoral head (AVN) were assessed. Hips were divided into satisfactory (Severin I/II) and unsatisfactory group (Severin III/IV). Finally, 87 hips (91.5%) had satisfactory and 8 (8.5%) unsatisfactory outcomes. The RI before PO was significantly higher in unsatisfactory (49.6 ± 9%) than in satisfactory group (30.6%±11.8%). All patients without AVN had satisfactory outcome, while it was 78.9% of patients with AVN. Logistic regression analysis showed that higher AVN grade and RI before PO were risk factors for unsatisfactory outcome. Satisfactory outcome was obtained in all hips with RI < 33% before PO, while it was 79.5% if RI > 33% before PO (79.5%). There was no difference in the satisfactory rate between patients undergoing open reduction (66.7%) and those not undergoing (83.3%). The rate of satisfactory outcome in patients undergoing femoral osteotomy (63.6%) was lower than those without it (100%). In patients with RAD following CR, good outcome can be expected after PO alone. AVN and preoperative RI > 33% are risk factors for poor outcome. Additional open reduction and femoral osteotomy do not significantly improve outcome of PO in patients with preoperative RI > 33%.

Arthroscopic debridement and reduction is an effective procedure for failed closed reduction in young children with developmental dislocation of the hip

PURPOSE

To assess the efficacy of arthroscopic debridement and reduction through two medial portals for the treatment of developmental dislocation of the hip (DDH) with failure of initial closed reduction and to explore key pathological structures obstructing reduction.

METHODS

Forty-eight children with 58 irreducible dislocated hips treated by arthroscopic reduction between January 2017 and December 2020 were retrospectively evaluated. Arthroscopic reduction was performed via two medial portals located in the superior and inferior adductor longus. All intra-articular obstacles were eliminated via arthroscopy, followed by manual reduction and spica cast immobilization. The surgical duration, extent of improvement in the safe zone, and extent of secondary surgical treatment were noted. All the children were followed up for > 24 months. Hip function and radiographic outcomes were evaluated.

RESULTS

All 58 hips showed safe zone improvement and concentric reduction after arthroscopic debridement. Hypertrophic ligamentum teres and thickened pulvinars were detected and resected in all hips. Constrictive capsules preventing reduction were observed in 15 hips, which needed to be further released. No inverted labrum was observed. Secondary surgery was performed in four hips with redislocation and seven hips with subluxation during follow-up. The remaining 47 hips (81.03%) maintained their reduction at the last follow-up. Excellent and good clinical outcomes were achieved in 95.74% of patients according to McKay's criteria. Two hips, three hips, and one hip were diagnosed with grade I, II, and III osteonecrosis of the femoral head, respectively.

CONCLUSION

This study demonstrated that arthroscopic debridement and reduction is a safe and feasible choice for treating irreducible DDH.

Closed reduction evaluation in dysplastic hip with the Ömeroğlu system in children aged 24 to 36 months

Closed reduction (CR) as an initial treatment for developmental hip dysplasia of the hip (DDH) in children aged 24 to 36 months is debatable; however, it could have better results than open reduction (OR) or osteotomies, because it is minimally invasive. The purpose of this study was to evaluate the radiological results in children (24-36 months) with DDH initially treated with CR. Initial, subsequent, final anteroposterior pelvic radiological records were retrospectively analyzed. The International Hip Dysplasia Institute was used to classify the initial dislocations. To evaluate the final radiological results after CR (initial treatment) or additional treatment (CR failed), the Ömeroğlu system was used (6 points excellent, 5 good, 4 fair-plus, 3 fair-minus, and ≤2 poor). The degree of acetabular dysplasia was estimated using the initial acetabular index and the final acetabular index, Buchholz-Ogden classification was used to measure avascular necrosis (AVN). A total of 98 radiological records were eligible, including 53 patients (65 hips). Fifteen hips (23.1%) were redislocated, OR with femoral osteotomy and pelvic osteotomy was the preferred surgical treatment 9 (13.8%). The initial acetabular index versus final acetabular index in total population was (38.9º ± 6.8º) and (31.9º ± 6.8º), respectively (t = 6.5, P < .001). The prevalence of AVN was 40%. Overall AVN in OR, femoral osteotomy and pelvic osteotomy were 73.3% versus CR 30%, P = .003. Unsatisfactory results ≤ 4 points on the Ömeroğlu system were observed in hips that required OR with femoral and pelvic osteotomy. Hips with DDH treated with CR initially might had better radiological results than those treated with OR and femoral and pelvic osteotomies. Regular, good, and excellent results, ≥4 points on the Ömeroğlu system, could be estimated in 57% of the cases, in whom CR was successful. AVN is frequently observed in hips with failed CR.

Evaluation of the short-term curative effect of closed reduction in the treatment of developmental dysplasia of the hip based on three-dimensional magnetic resonance imaging finite element analysis

Background

Based on the Digital Imaging and Communications in Medicine (DICOM) data of three-dimensional magnetic resonance imaging (3D-MRI), finite element models of the hip joints of children with developmental dysplasia of the hip were established. The primary objectives included simulation and analysis of the finite element model pre- and post-closed reduction under different stances and loads, and evaluation of the size and distribution of von Mises stress in the acetabulum and femoral head pre- and post-operation and the short-term effects.

Methods

Acetabular index measurements of both the unaffected and affected sides were conducted, alongside International Hip Dysplasia Institute (IHDI) classification of the affected hip. Establishing the finite element model of both the affected and unaffected hips was based on the 3D-T1WI sequence DICOM data, using Mimics, 3-matic, and Ansys software, before and after closed reduction surgery. The size and distribution data of von Mises stress on the affected side of the acetabulum and femoral head were collected pre- and post-operation.

Results

The study indicated that the increasing acetabular index of the affected hip was directly proportional to the increasing severity based on IHDI classification (P < 0.05). Preoperative IHDI classification significantly correlated with the von Mises stress (r = 0.560–0.569, 0.562–0.564, P < 0.05). Under different stances and load conditions, the von Mises stress on the affected side post-operation was lower than that noted pre-operation (P < 0.01), while that on the acetabulum increased proportionally to the load. Although the magnitude and distribution of von Mises stress on the affected side of the acetabulum were similar to those on the healthy side post-operation, there were statistical differences between the two (P < 0.01). The von Mises stress of the lateral column of the femoral head post-operation was significantly lower than that noted pre-operation (P < 0.01). While the high-stress points of the lateral column disappeared post-operation, the von Mises stress was evenly distributed in the femoral head.

Conclusions

The 3D-MRI finite element could provide the von Mises stress value and distribution characteristics of the acetabulum and femoral head pre- and post-operation. Closed reduction can, therefore, improve the size and distribution of von Mises stress on the affected acetabulum and femoral head.

Anterior approach with mini-bikini incision in open reduction in infants with developmental dysplasia of the hip

Purpose

The anterior and medial approaches in open reduction for developmental dysplasia of the hip (DDH) had been widely used. The former could not directly approach the intra-articular interposition, while the latter had been associated with injury to blood vessel and avascular necrosis (AVN) of the femoral head. Meanwhile, the bikini incision had also been mentioned in some studies. The purpose of this study was to introduce a modified anterior approach through a mini-bikini incision and report its short-term outcomes.

Methods

Data of DDH patients younger than 2 years at the time of surgery who had received this mini-bikini incision between June 2013 and December 2018 were collected. The surgical technique, operation duration, intraoperative blood loss, and length of incision were recorded in detail. In the latest follow up, the objective measurement of the scar and the subjective feeling towards the scar were collected. X-ray and magnetic resonance imaging (MRI) were performed at the last follow-up, and the incidence of residual dysplasia, redislocation, and femoral head AVN was analyzed.

Results

Forty-three cases (49 hips) were included with an averaged follow-up of 43 months. The operation duration was 22 min, and the blood loss was 9.8 ml on average. The length of the scar averaged 2.6 cm. The mean University of North Carolina “4P” scar scale (UNC4P) for the scar was 0.92, and no patients complained numbness. Overall, all the parents were satisfied with the cosmetic appearance. The mean acetabular index (AI) was 27.42° ± 6.41° in dislocated hip in the last follow-up. One hip redislocated soon after the operation and was reduced in a closed manner right away. MRI showed improved coverage but still some residual dysplasia that was in accordance with the post-operative recovery nature. Four hips (8%) had signs of AVN in X-ray.

Conclusion

Open reduction through the anterior approach with the mini-bikini incision was a safe procedure with comparable outcomes to classical approaches. It would be a complementary approach for DDH patients younger than 2 years old who need an open reduction.