Mathematical calculation of the difference in shortening length after two types of proximal femoral varus and an investigation of their applicable conditions: an own-pair design

BACKGROUND

The shortening length of the lower extremity after the proximal femoral osteotomy is an important issue to be considered in preoperative planning of developmental dysplasia of the hip (DDH) in children. There is still a lack of research on shortening the length of the lower extremities in different proximal femoral osteotomy varus styles. We aimed to verify the relationship between the shortening length after "point-to-face" and "face-to-face" varus osteotomy and proposed a formula for calculating the difference in shortening length and verified its feasibility.

METHODS

Fifty-five children with unilateral DDH were enrolled. The preoperative hip CT data were imported into mimics 21, 3-Matic 10 (Materialise, Leuven, Belgium) for femoral reconstruction and simulated osteotomy, and the difference (t) was calculated by directly measuring the length of the proximal femur after osteotomy. d* sinθ was measured in a three-dimensional environment to calculate the difference in femoral shortening length between the two osteotomy methods (t').

RESULTS

The results of the direct measurement method and the formula measurement method are shown in the table; the differences in the results of the femoral shortening length difference were not statistically significant (P > 0.05). The limits of agreement (95%) of the difference values using Bland-Altman analysis were between - 0.50 and 0.46 mm, with a mean of - 0.02 mm, indicating a high agreement between the two methods. r = 0.99 (P < 0.05) for the Pearson correlation analysis between the direct measurement method and the calculated method showed that the two methods were significantly correlated.

CONCLUSIONS

The derived formula can accurately calculate the difference in the shortening length of the proximal femur after "point-to-face" and "face-to-face" varus osteotomy in children with DDH, which is suitable for clinical application.

Modified Smith-Petersen approach with rectus-sparing reduces severe avascular necrosis for developmental dysplasia of the hip at walking age: minimum 5-year follow-up

BACKGROUND

Developmental dysplasia of the hip (DDH) is one of the most common orthopedic malformations in children. Open reduction for DDH at walking age remains a major concern. The goal of this study is to evaluate the mid-term effect of a modified Smith-Petersen approach which preserves the rectus femoris on DDH at walking age, in particular avascular necrosis (AVN).

METHODS

A retrospective review of DDH patients aged between 12 and 24 months was carried out between January 2010 and June 2016. Open reduction through the Smith-Petersen approach (Group A) and modified Smith-Petersen approach, which preserves the rectus femoris (Group B), were both used. Measurement of hip geometry included acetabular index, the International Hip Dysplasia Institute classification, and AVN degree. Clinical records included operation time, bleeding volume, and abduction angle.

RESULTS

There were 101 children (119 hips) with DDH who met the inclusion criteria. There were 66 hips in Group A and 53 in Group B. The mean surgical age at open reduction was 17.0 ± 2.4 months, with a mean 104.9 ± 19.5 months at last follow-up. There was no statistical difference in surgical age between the two groups (17.2 vs. 16.4 months). There was no significant difference in the incidence of all types of clinically significant AVN between group A and group B (27.3 vs. 18.9%), but the incidence of severe AVN was lower in group B (19.7 vs. 5.7%, P = 0.026). In addition, the lower the age at the time of open reduction, the lower the severity of AVN (P = 0.002).

CONCLUSIONS

These mid-term data suggest that the modified Smith-Petersen approach with rectus-sparing could reduce severe AVN more than the classical Smith-Peterson approach in open reduction in DDH at walking age. In addition, early open reduction can reduce the postoperative degree of AVN.

Clinical and sonographic improvement of developmental dysplasia of the hip: analysis of 948 patients

BACKGROUND

Developmental dysplasia of the hip is a common condition, which varies in severity. Abduction treatment is widely used to correct the development of the hips, but mild forms of DDH can also recover spontaneously. The purpose of this study was to evaluate factors affecting the rate of improvement of developmental dysplasia of the hip, and evaluate any risk factors slowing the process.

MATERIAL AND METHODS

The study population consisted of patients diagnosed with DDH in Tampere University hospital in the years 1998-2018. Data were retrospectively collected, and associations between clinical variables and rate of improvement were analyzed. Alpha angles were assessed monthly, and associations between risk factors and improvement of alpha angles were studied. A total of 948 patients were included in the analysis.

RESULTS

More severe first status of the hips was associated with faster improvement in dynamic ultrasound compared to milder DDH in univariate design in first 3 months of age; in the multivariable design, Ortolani positivity was conversely associated with lower alpha angles in 1-month follow-up. Immediate abduction treatment was associated with faster recovery rate compared to delayed abduction or watchful waiting. Female sex and positive family history were associated with slower rate of improvement and lower alpha angles. In multivariable design, female sex, positive family history and treatment strategy remained statistically significant as initiation time of the treatment explained the first found association of clinical hip status and the recovery rate after 2 months of age.

CONCLUSION

Female sex and positive family history might be independent risk factors for slower recovery in DDH before 6 months of age. These children might need special attention in their follow-up plans and abduction treatment.

Comparison of Transfer Learning Models in Pelvic Tilt and Rotation Measurement in Pediatric Anteroposterior Pelvic Radiographs

The rotation and tilt of the pelvis during anteroposterior pelvic radiography can lead to misdiagnosis of developmental dysplasia of the hip (DDH) in children. At present, no method exists for accurately and conveniently measuring the precise rotation and tilt angles of pelvic on radiographs. The objective of this study was to develop several rotation and tilt measurement models using transfer learning and digital reconstructed radiographs (DRRs), and to compare their performances on pelvic radiographs. Based on the inclusion criteria, 30 of 92 children who underwent 3D hip CT scans at Xijing Hospital from 2015 to 2020 were included in the study. Using DRR techniques, radiographs were generated by rotating and tilting the pelvis in CT datasets at - 12 to 12° (projected every 3°) and were randomized to a 2:1:1 ratio of training dataset, validation dataset, and test dataset. Five pre-trained networks, including VGG16, Xception, VGG19, ResNet50 and InceptionV3 were used to develop pelvic rotation measurement models and tilt measurement models, and these models were trained with training dataset. The callback function was used during the training to slow down the learning rate when learning was stalled. Then, the validation set was used to optimize each model and compare their performances. At last, we tested the final performances of optimal rotation measurement model and optimal tilt measurement model on test dataset. The mean absolute error (MAE) was employed to assess the performance of the models. A total of 2430 pelvic DRRs were collected based on 30 CT datasets. Among 5 pre-trained transfer learning models, VGG16-Tilt achieved the best tilt prediction performance at the same BS and different LR. VGG16-Tilt model achieved its best performance on validation set at LR = 0.001 and BS = 4, and the final MAE on the test set was 0.5250°. In terms of rotation prediction, VGG16-Rotation also achieved the best performance, and it achieved its best performance on validation set at LR = 0.002 and BS = 8. The final MAE of VGG16-Rotation on the test set was 1.0731°. Pretrained transfer learning models worked well in predicting tilt and rotation angles of the pelvis on radiographs in children. Among them, VGG16-Tilt and VGG16-Rotation had the best effect in dealing with such problems despite their simple structures. These models deployed in devices can give orthopedic surgeons a powerful aid in DDH diagnosis.

Long term results of the Bicontact D stem in dysplastic osteoarthritis: a 10-15 year follow-up study

PURPOSE

The purpose of the present study was to investigate the results of total hip arthroplasty (THA) using the Bicontact D stem with a minimum 10 year follow-up that focused on patients with developmental dysplasia of the hip (DDH).

METHODS

One hundred five patients with osteoarthritis due to DDH who underwent primary THA were included in this study. The mean final follow-up period was 12.7 ± 1.2 years (range 10-15 years). All cases were evaluated both clinically and radiographically, and Kaplan-Meier survivorship was determined as stem revision for any reason as the end point.

RESULTS

Modified Harris hip score averaged 89.0 ± 1.1 (range 60-98) at the final follow-up. The survivorship was 99.0% (95% confidence interval 93.4-99.9%) at 15.0 years, and only one hip with a well-fixed stem required stem revision due to recurrent dislocations. Cortical hypertrophy (CH) was observed in 40 of 105 hips (38.1%), and stress shielding (SS) progressed to grade 3 or 4 in six hips (6 of 105 hips: 5.7%) during the study period. Among the six hips with progressed SS, Dorr type C proximal femoral geometry was seen in five hips.

CONCLUSION

This study of 105 THAs using the Bicontact D stem that focused on DDH patients with a minimum 10 year follow-up period achieved satisfactory clinical and radiological outcomes. Dorr type C proximal femoral geometry could be considered a risk factor for progressed SS.

Watchful waiting for the undisplaced hip dysplasia when undergoing contralateral hip reconstruction

PURPOSE

Patients undergoing surgical reduction of the dislocated hip secondary to developmental dysplasia may have a contralateral undisplaced dysplastic hip. This study aimed to compare the observation of the contralateral undisplaced dysplastic hip with the treatment by acetabuloplasty in terms of persistent dysplasia to determine the need for bilateral surgery.

METHODS

Acetabular dysplasia was defined by an acetabular index (AI) of more than 30 degrees plus a center edge angle (CEA) of less than 20 degrees. A surgical database was queried retrospectively for a cohort between 2008 and 2016. Inclusion criteria were aged between 1 and 6 years, unilateral developmental dysplasia (international hip dysplasia institute grade 1) with contralateral dislocation, no previous treatment and a minimum follow-up of 1 year.

RESULTS

Fifty-seven patients were included, 40 in the observation group and 17 in the acetabuloplasty group. The mean age (interquartile range) was 20 (17-23) months, and the mean follow-up was 42 (22-62) months. The baseline values were similar for both groups. At the final follow-up, no hip had dysplasia, as specified a priori in either group, but the final AI and CEA were corrected more in the acetabuloplasty group (p < 0.001). Based on the adjusted analysis, both acetabuloplasty and follow-up without treatment were associated with improved acetabular coverage.

CONCLUSION

Watchful expectancy of undisplaced hip dysplasia presenting in patients undergoing contralateral hip reconstruction during years of acetabular growth is safe as the risk of persistent dysplasia and additional surgery is low.

LEVEL OF EVIDENCE

III.

Surgical procedures in infants with early diagnoses of developmental dysplasia of the hip. A prospective 4-year follow-up study

Background

Dysplastic hips infants may normalize spontaneously without any intervention due to the natural growth. However, some infants need one or more surgical interventions to achieve stable and non-dysplastic hips. The purpose of this study is to determine the proportion of infants diagnosed with DDH before the age of 6 months undergoing surgical procedures of the hip(s) before the age of four years and to determine the number and types of surgical procedures in each infant.

Methods

A prospective and consecutive study of all infants aged 0-6 months diagnosed with dysplasia of the hips in the combined paediatric orthopaedic and radiologic examination in the Region of Southern Denmark 2013-2017. From medical records, we obtained information about all surgical procedures in the hips including open or closed reductions, arthrographies, tenotomies, and pelvic osteotomies before the age of 4 years.

Results

Overall, 281 infants with hip dysplasia were included. The median age at first examination was 48 days. In 254 (90%) of the infants, the hips resolved spontaneously, and 27 (10%) needed one or more surgical interventions. Overall, the 27 infants had 47 surgical intervention as 12 infants had more than one intervention. One infants had five surgical interventions. The most frequent surgical procedures were closed reduction and arthrography with or without adductor tenotomy (58%) and pelvic osteotomy (27%). Among infants with surgical interventions, 23 (8.2%) had unstable hips, and four (1.4%) had stable hips. All four infants with stable hips had an arthrography and none required a pelvic osteotomy.

Discussion

This study supports the propensity for spontaneous normalization early dysplasia of the hips in infants. Only a small proportion of the infants needed surgical interventions to achieve stable and non-dysplastic hips.

Impact of the coronavirus disease 2019 pandemic on ultrasound screening of developmental dysplasia of the hip and follow-up imaging: a report from southeastern Turkey

Objective

To investigate the effect of coronavirus disease 2019 restrictions on ultrasound (US) screening of developmental dysplasia of the hip (DDH) in a children’s hospital.

Methods

The records of US screening of DDH were retrospectively evaluated in the pandemic period (April 2020 to July 2021) and the pre-pandemic period (January 2019 to February 2020). The monthly US number, sex, radiologist number, and age at the initial examination were recorded.

Results

A total of 6107 US scans were performed during the pre-pandemic period, which significantly decreased to 3340 during the pandemic. The number of monthly US scans performed did not change between the pre-pandemic (142.7/month) and pandemic (128.2/month) periods. The number of delayed examinations in the total population did not significantly change between the two periods. However, the number of delayed examinations in patients with abnormal hips was significantly increased during the pandemic compared with that in the pre-pandemic period.

Conclusions

Coronavirus disease 2019 restrictions decreased the US screening rate of DDH by almost half, but the number of US scans performed by each radiologist was unchanged. The compliance with follow-up recommendations was reduced by half, which may lead to an increase in the incidence of delayed and untreated DDH cases.

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

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.

[Status quo of screening for hip dysplasia]

Since the first description of the ultrasound examination of the infant hip by Graf in 1980 this technique has impressively demonstrated that it lives up to its promise very well. In the implementation of hip ultrasound in the German pediatric guidelines it was hoped that it would improve the sensitivity and specificity of the early detection of dislocated and dysplastic joints in comparison to a general clinical hip screening. Furthermore, it has been repeatedly shown that general newborn hip ultrasound screening according to Graf can significantly reduce not only the treatment rate but also the invasiveness. Consequentially, the cost of treatment as well as the rate of late presenting developmental dysplasia of the hip (DDH) can also be significantly reduced. Despite those proven merits the meaningfulness of general hip ultrasound screening in infancy is still questioned, especially in the Anglo-American world. This article reviews how this misconception came about.

Acetabular reconstruction with femoral head autograft in primary total hip arthroplasty through a direct anterior approach is a reliable option for patients with secondary osteoarthritis due to developmental dysplasia of the hip

BACKGROUND

Developmental dysplasia is challenging to treat with total hip arthroplasty via the direct anterior approach (DAA). Reconstructing the former anatomy while restoring the acetabular bone stock for future revisions in this young patient collective combined with the known advantages of the DAA would be desirable. The purpose of this study was to analyze the feasibility, radiographic outcome and clinical outcome of primary uncemented total hip arthroplasty with bulk femoral head autograft for acetabular augmentation through a DAA with a minimal follow-up of 12 months.

METHODS

A retrospective, consecutive series from March 2006 to March 2018 of 29 primary total hip arthroplasty with acetabular augmentation with bulk femoral head autograft through a direct anterior approach was identified. All complications, reoperations and failures were analyzed. Radiographic and clinical outcome was measured.

RESULTS

24 patients (29 hips) with a mean age of 43 (18-75) years and a mean follow-up of 35 months (12-137) were included. Surgical indication was secondary osteoarthritis for developmental dysplasia of the hip (Hartofilakidis Grade A (n = 19), B (n = 10)) in all cases. We noted no conversion of the approach, no dislocation and no acetabular loosening. The center of rotation was significantly distalized by a mean of 9 mm (0-23) and significantly medialized by a mean of 18 mm (6-29). The bone graft was fully integrated after 12 months in all cases.

CONCLUSION

Acetabular reconstruction with femoral head autograft in primary THA through a direct anterior approach seems to be a reliable option for the treatment of secondary osteoarthritis in patients with DDH Hartofilakidis grade A and B. Prospective cohort studies with a large sample population and a long-term follow-up are necessary to confirm our findings.

Physical impairments in Adults with Developmental Dysplasia of the Hip (DDH) undergoing Periacetabular osteotomy (PAO): A Systematic Review and Meta-Analysis

Background

Developmental dysplasia of the hip (DDH) is a condition associated with hip pain and impairments. Periacetabular osteotomy (PAO) is a common surgical treatment for DDH. Outcomes following PAO have historically been based on radiology or patient reported outcomes, and not physical impairments.

Objective

To investigate differences in physical impairments in adults with DDH undergoing PAO compared with asymptomatic participants, and to investigate pre- to post-PAO changes in physical impairments.

Design

Systematic review with meta-analysis.

Methods

A literature search was performed in five databases (MEDLINE, CINAHL, EMBASE, Sports Discuss, and PsychINFO), using the PRISMA checklist. Studies were considered eligible if patients were aged 15 years and older, treated with PAO for DDH and if they included a physical impairment outcome measure. Two independent reviewers performed data extraction and assessed methodological quality, using a modified version of the Downs and Black checklist.

Results

Of 5,017 studies, 24 studies were included with 2190 patients. The methodological quality scores ranged from 39% to 88%. With low level of evidence, meta-analysis showed 58% of patients had a positive anterior impingement test (95%CI: 39-76%), prior to PAO and one to three years after PAO. Five years after PAO, the proportion fell to 17% (95%CI: 11-24%). Prior to PAO, patients with DDH walked with a lower peak hip extension angle, compared to asymptomatic participants (SMD 0.65 (95%CI 0.21-1.10). Best evidence synthesis of non-pooled data showed limited evidence of increased walking velocity, stride length and improved hip flexion and extension moment 18-months post-PAO compared to pre-op. Cadence, hip abduction and hip flexion strength did not change.

Conclusion

Most patients with DDH have a positive hip impingement test, pre-PAO. Compared to asymptomatic participants, patients with DDH demonstrate physical impairments during walking which appear to improve after surgery. Hip abduction and flexion strength did not change pre- to post-PAO.

Level of Evidence

1b.

Effect of Hip Joint Center on Multi-body Dynamics and Contact Mechanics of Hip Arthroplasty for Crowe IV Dysplasia

OBJECTIVE

To investigate the hip joint forces, Von Mises stress, contact pressure and micro-motion of hip prosthesis for developmental dysplasia of the hip (DDH) patients under different hip joint centers using musculoskeletal (MSK) multi-body dynamics and finite element analysis.

METHODS

Both MSK multi-body dynamics model and finite element (FE) model were based on CT data of a young female DDH patient with total hip replacement and were developed to study the biomechanics of the S-ROM hip prosthesis. The same offset of hip joint center along all six orientations compared with the standard position was set to predict its effects on both MSK multi-body dynamics and contact mechanics during one gait cycle.

RESULTS

The hip joint forces in the entire walking gait cycle showed two peak values and clear differences between them under different hip joint centers. The hip joint force increased when the hip joint center moved posteriorly (2101 N) and laterally (1969 N) to the anatomical center (1848 N) at the first peak by 13.7% and 6.6%, respectively. The hip joint force increased sharply when the hip center deviated laterally (2115 N) and anteriorly (2407 N), respectively, from the standard position (1742 N) at the second peak. For the sleeve of the S-ROM prosthesis, the maximum Von Mises stress and contact pressure of the sleeve increased if the hip joint center deviated from the anatomical center posteriorly at the first peak. However, the Von Mises stresses and contact pressure increased at anterior and lateral orientations, compared to that of the standard position at the second peak. Small changes were observed for the maximum relative sliding distance along most of the orientations at both peaks except in the lateral and medial orientations, in which an increase of 8.6% and a decrease of 13.6% were observed, respectively.

CONCLUSION

The hip joint center obviously influenced the hip joint forces, stress, contact pressure and micro-motion of the hip implant for this female patient.

Biomechanical Characteristics of the Femoral Isthmus during Total Hip Arthroplasty in Patients with Adult Osteoporosis and Developmental Dysplasia of the Hip: A Finite Element Analysis

Objective

This study investigated the underlying mechanisms of high fracture incidence in the femoral isthmus from a biomechanical perspective.

Methods

We retrospectively analyzed a total of 923 primary total hip arthroplasty (THA) patients and 355 osteoporosis (OP) patients admitted from January 2010 to January 2018. Through a series of screening conditions, 47 patients from each group were selected for inclusion in the study. The datasets on the unaffected side and affected side of the patients with unilateral developmental dysplasia of the hip (uDDH) were respectively classified as the normal group (Group I) and he tDDH group (Group II), and that of patients with osteoporosis were classified as the OP group (Group III). In this study, first, we collected computed tomography (CT) images and measured geometric parameters (inner and outer diameters) of the isthmus. Thereafter, to study biomechanical properties, we established six finite element models and calculated values of von Mises stress for each group with the methods of data conversion and grid processing.

Results

Compared with those of patients in the normal group, the values of the inner and outer diameters of femoral isthmus of patients in the DDH group were significantly lower (P < 0.001), while the inner diameters of patients in the OP group were significantly higher (P < 0.001) and the outer diameters of patients in the OP group showed no significant difference (P> 0.05). The cortical rates of patients in the normal group and the DDH group appeared insignificant (P > 0.05), and those of patients in normal group were significantly higher than those of patients in the OP group (P < 0.001). Moreover, patients in the DDH group showed a higher von Mises stress value than patients in the normal group (P < 0.001), but statistically speaking the values between patients in the OP and normal groups were insignificant (P > 0.05).

Conclusions

The relatively shorter inner and outer diameters of the isthmus in DDH resulted in intensive von Mises stress under the torque of the hip location, and induced a high fracture incidence. However, in patients in the OP group, the geometric morphology exhibited no anatomical variation, and the fracture was not due to the intensity of von Mises stress.

Case report: genetic analysis of a child with 18q deletion syndrome and developmental dysplasia of the hip

OBJECTIVE

To analyze the genotypes and phenotypes of a child with developmental dysplasia of the hip (DDH), developmental delays, recurrent fever, hypothyroidism and cleft palate.

METHODS

G-banding karyotyping analysis and next-generation sequencing (NGS) were performed for the patient. The genotypes of the parents of the patient were verified by copy number variation analysis and Sanger sequencing to determine the source of variations.

RESULTS

The karyotype of the patient was 46, XX. A 10.44 Mb deletion (chr18:67562936-78005270del) at 18q22.2q23 was found by NGS. We identified 2 HSPG2 mutations (chr1: 22206699, c.2244C > A, exon 17, p.H748Q; chr1: 22157321-22157321, c.11671 + 154insA, intron). One mutation was inherited from the father, and the other was inherited from the mother.

CONCLUSION

This is the first 18q deletion syndrome case accompanied by DDH. Most phenotypes of this patient, such as developmental delays and cleft palate, may be related to the 18q22.2q23 deletion, but no variants in genes related to DDH were found in this deletion region. DDH may be related to mutations of HSPG2.

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.

[Short-term effectiveness of structural bone graft and total hip arthroplasty through direct anterior approach in lateral decubitus position for Crowe type and developmental dysplasia of the hip]

Objective

To explore the feasibility and effectiveness of total hip arthroplasty (THA) with acetabulum structural bone grafting using autogenous femoral head through direct anterior approach (DAA) in lateral decubitus position in the treatment of Crowe type Ⅲ and Ⅳ developmental dysplasia of the hip (DDH).

Methods

Between June 2016 and July 2020, 12 patients with Crowe type Ⅲ and Ⅳ DDH were treated with THA with acetabulum structural bone grafting using autogenous femoral head through DAA in lateral decubitus position. There were 2 males and 10 females with an average age of 60.2 years (range, 50-79 years). Crowe classification was type Ⅲ in 10 hips and type Ⅳ in 2 hips. The preoperative Harris score of hip joint was 48.8±7.5, the difference in length of both lower extremities was (3.0±0.7) cm, and the visual analogue scale (VAS) score during activity was 7.2±0.9. The surgical incision length, operation time, intraoperative blood loss, and complications were recorded; the position and press-fitting of acetabulum and femoral prosthesis were observed after operation, and the difference in length of both lower extremities was measured; the horizontal coverage of acetabular cup and bone graft were measured, the healing with the host bone and the loosening of the prosthesis were evaluated; Harris score was used to evaluate hip joint function, and VAS score was used to evaluate patients' pain during activity.

Results

The average surgical incision length was 9.3 cm, the average operation time was 117 minutes, and the average intraoperative blood loss was 283 mL. Two patients (16.7%) received blood transfusion during operation. There was no acetabular and femoral fractures during operation. All incisions healed by first intention, without dislocation, periprosthetic infection, sciatic nerve injury, deep venous thrombosis, and other complications. One patient had lateral femoral cutaneous nerve injury after operation. X-ray films at discharge showed a total acetabular cup level coverage of 93%-100%, with an average of 97.8%, and a bone graft level coverage of 25%-45%, with an average of 31.1%. All the 12 patients were followed up 22-71 months, with an average of 42.2 months. At last follow-up, the Harris score of hip joint was 89.7±3.9, the difference in length of both lower extremities was (0.9±0.4) cm, and the VAS score during activity was 1.1±0.6, which were significantly different from those before operation (P<0.05). During follow-up, there was no patient who needed hip revision surgery because of prosthesis loosening. At last follow-up, there was no translucent line between the graft and the host bone, the graft was fused, the position was good, and there was no obvious movement. One patient had one screw fracture and bone resorption at the outer edge of the graft, but the bone graft did not displace and healed well.

Conclusion

THA with acetabulum structural bone grafting using autogenous femoral head through DAA in lateral decubitus position in the treatment of Crowe type Ⅲ and Ⅳ DDH is safe and reliable, and has satisfactory short-term effectiveness.

Coronal and sagittal spinopelvic alignment in the patients with unilateral developmental dysplasia of the hip: a prospective study

BACKGROUND

How the hip dysplasia affects the spinopelvic alignment in developmental dysplasia of the hip (DDH) patients is unclear, but it is an essential part for the management of this disease. This study aimed to investigate the coronal and sagittal spinopelvic alignment and the correlations between the spinopelvic parameters and the extent of hip dysplasia or the low back pain in unilateral DDH patients.

METHODS

From September 2016 to March 2021, 22 unilateral patients were enrolled in the DDH group with an average age of 43.6 years and 20 recruited healthy volunteers were assigned to the control group with an average age of 41.4 years. The Cobb angle, seventh cervical vertebra plumbline-central sacral vertical line (C7PL-CSVL), third lumbar vertebra inclination angle (L3IA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK) and lumbar lordosis (LL) were measured on the standing anteroposterior and lateral full-length standing spine radiographs. Additionally, the Oswestry Disability Index (ODI) and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were used to assess the degree of low back pain.

RESULTS

Cobb angle (8.68 ± 6.21° vs. 2.31 ± 0.12°), L3IA (4.80 ± 5.47° vs. 0.83 ± 0.51°), C7PL-CSVL (1.65 ± 1.57 cm vs. 0.48 ± 0.33 cm), PT (15.02 ± 9.55° vs. 9.99 ± 2.97°) and TLK (7.69 ± 6.66° vs. 3.54 ± 1.63°) were significantly larger in DDH patients, whereas LL (37.41 ± 17.17° vs. 48.79 ± 7.75°) was significantly smaller (P < 0.05). No correlation was found between significantly different spinopelvic parameters and the extent of dysplasia. Statistical analysis revealed correlations between ODI and Cobb angle (r = 0.59, P < 0.01), PT (r = 0.49, P = 0.02), TK (r =  -0.46, P = 0.03) and TLK (r = 0.44, P = 0.04). Correlations between JOABPQE score and the Cobb angle (r = -0.44, P = 0.04), L3IA (r = -0.53, P = 0.01), PT (r = -0.44, P = 0.04), and TK (r = 0.46, P = 0.03) were also observed.

CONCLUSIONS

Cobb angle, L3IA, C7PL-CSVL in coronal plane and PT, TLK in sagittal plane increased, while LL decreased in unilateral DDH patients. These significantly different spinopelvic parameters have no correlation with the extent of dysplasia. Changes in coronal and sagittal plane including Cobb angle, L3IA, PT, TK and TLK were associated with the low back pain in the patients with unilateral DDH.

Influence of implantation of a total hip endoprosthesis on the ipsilateral leg alignment: the effect of sex and dysplasia of the hip

INTRODUCTION

Differences in leg and hip morphology exist between sexes and developmental hip dysplasia is known to alter proximal femoral morphology. The purpose of this study was to determine whether existing differences in leg alignment due to sex or developmental hip dysplasia have an effect on changes in leg alignment after total hip arthroplasty.

MATERIALS AND METHODS

30 hip osteoarthritis patients underwent biplanar full-length radiography in the standing position preoperatively and 3 months after total hip arthroplasty. Differences in leg alignment between men and women and between patients with primary hip osteoarthritis and patients with developmental dysplasia before and after surgery were tested using a general linear model for repeated measures.

RESULTS

Implantation of a hip prosthesis had no differential effect on ipsilateral leg alignment in patients with hip osteoarthritis due to dysplasia and in patients with primary hip osteoarthritis. However, patients with hip osteoarthritis due to dysplasia had a 2.1° higher valgus both before and after surgery. After total hip arthroplasty, women had a significantly greater increase in varus angle (1.6° vs. 0°) and femoral offset (10.5 vs. 4.6 mm) compared with men. Because the change in acetabular offset was smaller (2.2 vs. 6.2 mm), the global femoral offset was only increased in women. Femoral torsion was constant for men (15.0° and 16.5°), whereas femoral torsion was significantly reduced in women (19.9° and 13.2°).

CONCLUSIONS

Hip arthroplasty has a greater effect on leg axis in women than in men. The axial leg alignment of women could change from a natural valgus to a varus alignment. Therefore, surgeons should consider the effects of total hip arthroplasty on leg alignment in patients with hip osteoarthritis. Whether these changes in leg alignment are also clinically relevant and lead to premature medial or lateral knee osteoarthritis should be investigated in future work.

TRIAL REGISTRATION

This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018.

Acetabular morphological variation in Asian patients with femoral neck fracture: A three-dimensional CT-based study

AIMS

The acetabular morphology varies greatly among individuals, and hypoplasia is more common in Asia than in Europe. Dislocation after bipolar hip arthroplasty (BHA) for femoral neck fracture occurs at a constant rate, and is affected by the acetabular morphology. This study aimed to clarify individual differences in the acetabula of Asian patients with displaced femoral neck fractures.

PATIENTS AND METHODS

Fifty patients with displaced femoral neck fractures were assessed (50 fractured hips, 50 non-fractured hips). On CT corrected by the anterior pelvic plane, the 100 hips were assessed regarding acetabular coverage (six parameters), acetabular depth (two parameters), and acetabular opening angle (four parameters). Additional parameters related to the fracture and sex were examined. The percentile of each parameter was shown for all hips.

RESULTS

There was no patient with hip dysplasia defined as superior acetabular sector angle (SASA) less than 110° Compared with men, women had a significantly smaller anterior acetabular sector angle (AASA) (p = 0.016), and significantly larger acetabular inclination angle (p = 0.006) and acetabular index angle (p = 0.034). In the group with a normal SASA, seven hips (7.3%) had an anterior wall defect (AASA<50°) and five hips (5.2%) had a posterior wall defect (posterior acetabular sector angle<90°).

CONCLUSION

Older adults with femoral neck fractures can have anterior wall and posterior wall defects, even if their SASA is normal. Hidden acetabular dysplasia may be related to post-BHA dislocation. So, our results suggest that is important to accurately evaluate the acetabulum of patients with femoral neck fracture before surgery.

Risk factors for re-dislocation after closed reduction in children with developmental dysplasia of the hip

OBJECTIVE

To investigate the risk factors for re-dislocation after the closed reduction in children with developmental dysplasia of the hip (DDH).

METHODS

The clinical data of 88 children aged ≤ 18 months with DDH (103 hips) who were treated with adductor muscle relaxation + closed reduction + plaster fixation at the Children's Hospital, Zhejiang University School of Medicine from January 2015 to December 2017, were retrospectively analyzed. According to the diagnostic criteria of hip dislocation, patients were divided into two groups: reduction group and re-dislocation group. The univariate and multivariate logistic regression analysis were applied to identify the risk factors for the re-dislocation of children.

RESULTS

Eighty-six patients (99 hips) successively underwent the treatment. 69 hips were fixed at the first intention, 9 hips at the second intention, and a total of 78 hips with no re-dislocation occurred till the last follow-up with a rate of 78.8%. The univariate analysis showed that preoperative acetabular index (AI), International Hip Dysplasia Institute (IHDI) grade, intraoperative hip flexion angle, and intraoperative head-socket spacing were significantly related to the occurrence of re-dislocation after closed-reduction. The multivariate logistic regression analysis showed that preoperative AI > 40.5° ( OR=5.57, P<0.01), flexion angle < 80.5° ( OR=4.93, P<0.01) and head-socket distance > 6.95 mm ( OR=8.42, P<0.01) were risk factors for the re-dislocation. The area under the receiver operator characteristic curve was 0.91 when preoperative AI > 40.5°, flexion angle < 80.5°, head-socket distance > 6.95 mm, and IHDI grade were used to predict the occurrence of re-dislocation, and the sensitivity and specificity were 0.72 and 0.87, respectively.

CONCLUSIONS

Preoperative AI > 40.5°, intraoperative hip flexion angle < 80.5°, and head-socket distance > 6.95 mm are risk factors for postoperative re-dislocation in children with DDH. These risk factors combining with the IHDI grade would be better to predict the occurrence of re-dislocation.

A propensity score-matched comparison of patient satisfaction following periacetabular osteotomy or total hip arthroplasty for developmental dysplasia of the hip in an Asian cohort

BACKGROUND

No studies have compared patient satisfaction between periacetabular osteotomy (PAO) and total hip arthroplasty (THA) for osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH) in Asian cohorts.

METHODS

Multivariate analyses were applied to determine whether patient demographics and postoperative patient-reported outcomes were correlated with postoperative patient satisfaction in 737 DDH patients (251 PAO and 486 THA patients). Additionally, postoperative patient satisfaction, Oxford Hip Score (OHS), University of California-Los Angeles (UCLA) activity score, and sports participation were compared between propensity-matched PAO and THA patients for OA secondary to DDH (Kellgren-Lawrence grade II: 32 PAO and 16 THA patients, grade III: 20 PAO and 40 THA patients).

RESULTS

Of the 737 patients, 663 patients (90%) were postoperatively satisfied. Multivariate analysis demonstrated that THA was positively correlated with patient satisfaction. Furthermore, high postoperative OHS-pain, OHS-ADL, and UCLA scores were positively correlated with satisfaction. In propensity-matched PAO and THA patients, PAO elicited greater patient satisfaction than THA for KL grade II OA secondary to DDH, with comparable postoperative OHS (including the pain and ADL subscale), UCLA score, and sports participation rate. In contrast, THA resulted in better satisfaction and OHS-pain for KL grade III OA secondary to DDH, with comparable postoperative OHS-ADL, UCLA score, and sports participation rate in the 2 surgeries.

CONCLUSIONS

Both PAO and THA procedures offer distinct patient satisfaction advantages based on preoperative OA severity. These findings can assist in the clinical decision-making process for the surgical treatment of middle-aged patients with symptomatic DDH.

Arthroscopic labral repair combined with less invasive open-shelf acetabuloplasty for patients with developmental dysplasia of the hip

Hip arthroscopy has become widely used for intra-articular lesions, such as labral tears and femoral acetabular impingement. However, its use in patients with developmental dysplasia of the hip (DDH) has been controversial and has historically demonstrated mixed results, as acetabular dysplasia may cause instability due to insufficient bony coverage of the femoral head, thus causing excessive stress on the repaired labrum and cartilage. We devised a combined hip arthroscopic labral repair and a less invasive open-shelf procedure using a small skin incision as an anterolateral portal in hip arthroscopy. This novel procedure may improve the stability of the repaired labrum with a bony covering in a minimally invasive manner. Moreover, the shelf procedure can be performed under direct vision in a comparatively safe and precise manner. In total, 13 hips with DDH underwent the procedure for labral tears. All patients were females, with a mean age of 30 years. The mean follow-up period was 33 months. The mean Harris hip score improved from 74.2 to 93.6, and Oxford Hip score improved from 32.4 to 19.3. According to the Tönnis classification, the grade of arthritis preoperatively was grade 0 for nine hips and grade I for four hips. No radiographic progression of osteoarthritis was observed. It is possible that this novel procedure could be an effective treatment for labral tears with DDH and may prevent the early onset of secondary osteoarthritis. In this technical tip, we describe hip arthroscopic labral repair combined with a less invasive open-shelf acetabuloplasty in further detail.

Retrospective Comparison of Outcomes Between Closed and Open Reduction for Developmental Dysplasia of the Hip in Children Aged 6-24 Months

PURPOSE

We aimed to compare the outcomes between closed reduction (CR) and open reduction (OR) in children aged 6-24 months with developmental dysplasia of the hip (DDH) who could be reduced safely and stably by the closed reduction operation.

METHODS

We retrospectively reviewed the medical records of 77 patients who underwent CR or OR for DDH. Fifty-one patients (56 hips) underwent CR, 26 (29 hips) underwent OR. The demographic data, International Hip Dysplasia Institute classification and acetabular index (AI) before reduction and the centre-edge angle (CEA), AI, Alsberg angle (AA), Reimer's migration index (RMI), and height-to-width index (HWI) of the epiphysis were compared between two groups at the final follow-up. The percentage of coxa magna > 15% of the normal side and AA > 81° were calculated.

RESULTS

At the final follow-up, the mean AA in the CR and OR groups were 77.66° (60°-89°) and 81.97° (73°-91°) (p = 0.001), respectively, there were 32.14% and 58.62% of the hips with an AA > 81° (p = 0.019). The frequency of coxa magna > 15% of the normal side was higher in the OR group (60.9%) than in the CR group (6.5%) (p < 0.001). There was no difference in the improvement of AI, CEA, HWI, and RMI.

CONCLUSION

In children aged 6-24 months with DDH, if a stable and safe CR can be obtained but with medial joint space up to 6mm, CR should be attempted first.

Use of ultrasonography to evaluate early outcomes of reduction in developmental dysplasia of the hip

OBJECTIVE

To compare pubo-femoral distance (PFD) in normal hips and those treated for developmental dysplasia of the hip (DDH) and to investigate the value of ultrasonography from the medial hip in early follow-up of dislocated DDH after reduction.

MATERIALS AND METHODS

This study included 58 infants (49 females) with DDH who presented with 65 dislocated hips (51 unilateral and 7 bilateral). Dislocation was treated by closed reduction for 53 and open reduction for 12 hips. Ultrasonography on the medial side of the hip was performed within 1-2 weeks and 4 weeks after reduction. The distance from the pubic bone to the femoral head (PFD) was measured to assess the reduction and stability of the femoral head and compared to that on the contralateral side (control) in cases of unilateral DDH.

RESULTS

The PFD value for the normal group (2.9 ± 0.4 mm) was significantly less than that for the closed reduction group (4.9 ± 2.8 mm, P<0.001) and that for the open reduction group (4.4 ± 1.6 mm; P=0.02), but no difference in the PFD was observed between the closed reduction and the open reduction groups (P=0.73). Despite successful reduction, the PFD values in the successful reduction group remained higher than those of the normal hips.

CONCLUSION

PFD measurement by ultrasonography of the medial hip can be used to evaluate the effectiveness of reduction procedures in DDH. The clinical implications of post-reduction ultrasound evaluation in the diagnosis and long-term follow-up of outcomes require further research.