Residual axial plane deformities after hip reconstruction for developmental dysplasia of the hip after walking age

Can Computed Tomography Accurately Measure Acetabular Anterversion in Developmental Dysplasia of the Hip? Verification and Characterization Using 3D Printing Technology

BACKGROUND

One of the important pathologic changes in developmental dysplasia of the hip (DDH) is increased acetabular version angle (AA). Reasonable correction for excessive AA is an important step in the treatment of DDH, making accurate AA measurement very crucial. However, the results of different AA measurement methods vary. Thus, this study aimed to compare the difference in AA measurements between 2-dimensional computed tomography (2D-CT) and 3-dimensional computed tomography (3D-CT) in children with DDH and to identify the AA degree in children with DDH to guide treatment.

METHODS

AA was measured by 2D-CT and 3D-CT in 186 children with DDH, and the measurement results were compared with the physical measurement result in the 3D-printed pelvis (3D-PP) model. The 3D-PP was a 1:1 model identical to the human pelvis. All patients were unilaterally affected.

RESULTS

The results of AA measurement through 2D-CT, 3D-CT, and 3D-PP of normal hips were 14.0±6.6, 11.9±5.3, and 11.9±3.4 degrees, respectively, whereas those of the dislocated hips were 24.9±8.9, 19.8±5.2, and 19.5±4.3 degrees, respectively. In both the normal and dislocated hip groups, the results between 2D-CT and 3D-CT was significantly different (P<0.05), but there was no difference between the results of 3D-CT and 3D-PP (P>0.05). The AA of the normal and dislocated hips as measured by 3D-PP was 11.9±3.6 and 19.6±4.3 degrees, respectively, with statistically significant difference (P<0.05). In the dislocated hips, a significant positive correlation was found between age and AA (r=0.756, P<0.05) and between AA and degree of dislocation (r=0.837, P<0.05).

CONCLUSIONS

3D-CT is more accurate than 2D-CT for AA measurement, and compared with normal hips, AA in dislocated hips increased by ∼7.7 degrees on average. AA increases as age and degree of dislocation increase.

LEVEL OF EVIDENCE

Level II.

A radiological comparison of Salter and Pemberton osteotomies to improve acetabular deformations in developmental dysplasia of the hip

We investigated whether the following acetabular scores influence operative outcomes in patients with developmental dysplasia of the hip who underwent Salter innominate osteotomy (SIO) or Pemberton osteotomy (PO): the acetabular depth ratio (ADR), the acetabular index, the center-edge (CE) angle of Wiberg, and the femoral head migration rate (Reimer's index). A total of 47 hips were treated with SIO and 50 hips were treated with PO. Changes in ADR were greater in children who underwent PO compared with those who underwent SIO. However, the acetabular index, the center-edge angle, and Reimer's index did not differ between the groups at final follow-up. Children who underwent PO achieved an improved radiological ADR compared with those who underwent SIO on an average follow-up of 5 years after innominate osteotomy.

Does Salter innominate osteotomy with transiliac lengthening effect triradiate cartilage or cause posterior coverage insufficiency?

INTRODUCTION

To treat neglected developmental dysplasia of the hip (DDH), we performed Salter innominate osteotomy with a modification of transiliac lengthening. We asked whether this modified technique caused posterior coverage problems and triradiate cartilage injury.

METHODS

We retrospectively reviewed 45 patients with unilateral DDH treated by open reduction and femoral shortening and modified Salter innominate osteotomy. The age at operation was 38.44 +/- 19.79 months (mean +/- standard deviation). Minimum follow-up was 24 months (mean +/- standard deviation 49.84 +/- 27.73 months; range 24-112 months). We measured the tilt of the iliac bone (difference of preoperative and postoperative acetabular index values). We divided the hips into two groups. There were 29 hips in Group 1 (deviation amount <20 degrees ) and 16 hips in Group 2 (deviation amount > or =20 degrees ). At the latest follow-up, frontal and axial plane computed tomographic analyses were performed. We measured medial wall thickness, teardrop width, and hemipelvis heights to evaluate triradiate cartilage intactness indirectly. Posterior center edge angle, which reflects posterior coverage of the hip, was also measured.

RESULTS

We found no differences between groups regarding all measured parameters.

CONCLUSIONS

Modified Salter osteotomy with transiliac lengthening can be performed safely in the treatment of neglected DDH.

Femoral anteversion in developmental dysplasia of the hip

BACKGROUND

Limited data exist in the literature with regard to the amount of femoral anteversion in children with developmental dysplasia of the hip (DDH). The data that do exist are variable: certain studies cite increased version in DDH compared with normal while others have found no significant difference. The purpose of our study was to quantify the degree of femoral anteversion in a large, consecutive series of children with DDH.

METHODS

We performed a prospective study on 37 consecutive hips (30 patients) that were undergoing surgical procedures for DDH. After induction with general anesthesia (before the planned procedure), arthrograms were performed to allow accurate localization of the center of the femoral head. An anteroposterior radiograph was taken with the patient positioned supine and the knee flexed 90 degrees over the end of the operating table and the leg held perpendicular to the plane of the table. The limb was then rotated 90 degrees for the lateral radiograph. The offset of the center of the femoral head to the midline of the femoral shaft was measured in each view and a simple trigonometric relationship was used to calculate the femoral version.

RESULTS

The mean age of the children in our series was 33.5 months (range: 6 to 79 mo). There were 4 boys and 26 girls; 7 patients had bilateral involvement. The mean femoral anteversion was 50.3 degrees+/-17.9 degrees. Significant variability was found: the lowest femoral version measured 0 degrees and the highest measured 95.7 degrees.

CONCLUSIONS

In most of our children with DDH, femoral anteversion was increased compared with published norms; however, significant variation existed. Given the variability of femoral anteversion, we believe that an individualized surgical approach is warranted, including preoperative assessment of the femoral version followed by derotational femoral osteotomy only if indicated by the patient's specific torsional profile.

LEVEL OF EVIDENCE

Anatomic study.

Measurement of acetabular anteversion in developmental dysplasia of the hip in children by two- and three-dimensional computed tomography

This study assessed the angle of acetabular anteversion (AA) in 66 children with developmental dysplasia of the hip (132 hips: 24 left, 25 right, 17 bilateral and 49 unaffected hips as controls). The AA was measured by two- and three-dimensional computed tomography (2D-CT and 3D-CT). Measurements were taken by three observers and repeated 2 weeks later by one of these observers. Intra- and inter-observer agreement was analysed using the intra-class correlation coefficient. For all hips, the mean AA (+/-SD) measured by 2D-CT versus 3D-CT was statistically significantly different (15.76 +/- 5.23 degrees versus 16.76 +/- 4.43 degrees , respectively). The mean (+/-SD) AA by 3D-CT in unaffected and affected hips was also statistically significantly different (13.92 +/- 3.95 degrees versus 18.44 +/- 3.82 degrees , respectively). A significant positive correlation between age at presentation and AA was found in affected, but not unaffected, hips. The 3D-CT showed better intra- and inter-observer agreement than 2D-CT for assessing AA hence is a more reliable measurement of AA. An increased AA is one component of anatomical abnormalities in developmental dysplasia of the hip and the abnormality appears to worsen with age.

[Indications and results of corrective pelvic osteotomies in developmental dysplasia of the hip]

BACKGROUND

Joint-preserving reconstructive surgeries in children and adolescents remain challenging for orthopaedists with regard to indication and surgical technique. Besides skeletal maturity and tissue quality at the time of surgery, the kind and degree of deformity, the causative pathologies in secondary dysplasias, and the prognosis have to be considered when deciding for or against a surgical procedure. Developmental dysplasia of the hip (DDH) is the most frequent deformity that indicates reorienting surgery on the hip joint in children and adolescents. The aim of these procedures is to prevent early secondary osteoarthritis. For patients and families as well as for the orthopaedist, risk-benefit analysis is of major interest.

METHODS

In this study, the surgical techniques and specialties of different reconstructive operations are presented. Based on a review of the literature, the results of defined surgical methods are discussed and compared with own experiences.

RESULTS

Only limited information is available about the clinical long-term outcome after defined reconstructing surgery on the hip joint in children and adolescents. The degree of the deformity, the age of onset, and the surgical experience of the orthopaedist are crucial factors in decision making for or against a surgical treatment. In early childhood, acetabuloplasty and Salter osteotomy are widely accepted to correct DDH. Triple and periacetabular osteotomies are preferred and have shown promising results in late adolescence and young adults. When the triradiate cartilage (growth plate) is closed, good outcomes can be achieved by the Ganz osteotomy. Intertrochanteric varus and derotation osteotomies of the femur may serve as additional procedures for pelvic osteotomies and are rarely indicated as a single procedure today.

CONCLUSION

Reconstructive surgery on the hip joint improves function and may prevent early osteoarthritis and delay progression of cartilage degeneration in most patients when the indication and surgical technique are appropriate.