Prognosticating factors in acetabular development following reduction of developmental dysplasia of the hip

Hip Morphology on Post-Reduction MRI Predicts Residual Dysplasia 10 Years After Open or Closed Reduction

BACKGROUND

There is limited evidence supporting the value of morphological parameters on post-reduction magnetic resonance imaging (MRI) to predict long-term residual acetabular dysplasia (RAD) after closed or open reduction for the treatment of developmental dysplasia of the hip (DDH).

METHODS

We performed a retrospective study of 42 patients (47 hips) undergoing open or closed reduction with a minimum 10 years of follow-up; 39 (83%) of the hips were in female patients, and the median age at reduction was 6.3 months (interquartile range [IQR], 3.3 to 8.9 months). RAD was defined as additional surgery with an acetabular index >2 standard deviations above the age- and sex-specific population-based mean value or Severin classification grade of >2 at last follow-up. Acetabular version and depth-width ratio, coronal and axial femoroacetabular distance, cartilaginous and osseous acetabular indices, transverse ligament thickness, and the thickness of the medial and lateral (limbus) acetabular cartilage were measured on post-reduction MRI.

RESULTS

At the time of final follow-up, 24 (51%) of the hips had no RAD; 23 (49%) reached a failure end point at a median of 11.4 years (IQR, 7.6 to 15.4 years). Most post-reduction MRI measurements, with the exception of the cartilaginous acetabular index, revealed a significant distinction between the group with RAD and the group with no RAD when mean values were compared. The coronal femoroacetabular distance (area under the receiver operating characteristic curve [AUC], 0.95; 95% confidence interval [CI], 0.90 to 1.00), with a 5-mm cutoff, and limbus thickness (AUC, 0.91; 95% CI, 0.83 to 0.99), with a 4-mm cutoff, had the highest discriminatory ability. A 5-mm cutoff for the coronal femoroacetabular distance produced 96% sensitivity (95% CI, 78% to 100%), 83% specificity (95% CI, 63% to 95%), 85% positive predictive value (95% CI, 65% to 96%), and 95% negative predictive value (95% CI, 76% to 100%). A 4-mm cutoff for limbus thickness had 96% sensitivity (95% CI, 78% to 100%), 63% specificity (95% CI, 41% to 81%), 71% positive predictive value (95% CI, 52% to 86%), and 94% negative predictive value (95% CI, 70% to 100%).

CONCLUSIONS

Coronal femoroacetabular distance, a quantitative metric assessing a reduction's concentricity, and limbus thickness, a quantitative metric assessing the acetabulum's cartilaginous component, help to predict hips that will have RAD in the long term after closed or open reduction.

LEVEL OF EVIDENCE

Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

When to Combine Acetabular Osteotomy in Patients With Proximal Femoral Deformity Causing Residual Hip Dysplasia/Subluxation After Reduction of Developmental Dysplasia of the Hip

BACKGROUND

After the successful reduction of developmental dysplasia of the hip, residual hip dysplasia may persist and lead to early osteoarthritis. Femoral and/or acetabular osteotomy has been used to address this problem. The purpose of this study is to determine the indication of femoral versus combined femoral-acetabular osteotomy in the management of residual hip dysplasia.

METHODS

Fifty-five patients with unilateral dislocated-type dysplasia of the hip, who had residual hip dysplasia after reduction, underwent femoral osteotomy with or without acetabular osteotomy before 8 years of age, and were followed for more than 2 years and over 8 years of age, were the subjects of this retrospective study. Twenty-eight patients underwent femoral osteotomy only at a median age of 34 months (group F), and 27 underwent combined femoral-Dega osteotomy at a median age of 49 months (group C). Seventeen patients in group F and 4 in group C had an additional osteotomy due to persistent hip dysplasia. Acetabular index (AI), lateral center-edge angle, and center-head distance difference were measured on serial radiographs. The z-value of AI (Z AI ) was calculated. At the latest follow-up, patients in group F with Severin I/II who did not have an additional osteotomy were considered satisfactory, and patients with Severin III/IV or those who had an additional osteotomy were considered unsatisfactory. Preoperative variables were tested for the difference between satisfactory and unsatisfactory cases. Receiver operating characteristic analysis was performed to delineate a cutoff value of a significant parameter dividing the outcome.

RESULTS

AI and Z AI before index osteotomy were significant parameters predicting a satisfactory outcome in group F. Receiver operating characteristic analysis returned a cutoff value of Z AI 2.6 (Area Under the Curve=0.86, P =0.001). Eight of 12 cases (66.7%) with Z AI <2.6 in group F achieved a satisfactory outcome, whereas only 2 of 14 cases with Z AI ≥2.6 in group F did ( P =0.02).

CONCLUSION

Z AI 2.6 may serve as a threshold to combine acetabular osteotomy with femoral osteotomy in the management of residual hip dysplasia before 8 years of age.

LEVEL OF EVIDENCE

Therapeutic III.

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

Object

This study was designed to analyze the cartilaginous predictors of residual acetabular dysplasia (RAD) after early treatment of developmental dysplasia of the hip and their diagnostic accuracy.

Study design

Databases such as PubMed, Embase, Cochrane, and Web of science were searched to screen the literature. The quality of the literature was assessed by the QUADAS-2 tool. Qualitative and quantitative synthesis of literature were performed based on extracted data. For quantitative synthesis studies, the sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) curve with corresponding confidence intervals were calculated.

Results

For the cartilaginous acetabular index (CAI) group, the combined values of sensitivity, specificity, and DOR were 0.80 (95% CI = 0.54-0.93), 0.73 (95% CI = 0.57-0.84), and 10.62 (95% CI = 3.96-28.53), respectively. The corresponding values in the cartilaginous center-edge angle (CCE) group were 0.71 (95% CI = 0.57-0.82), 0.78 (95% CI = 0.66-0.87), and 8.64 (95% CI = 3.08-24.25), respectively. The area under the curve (AUC) of SROC was 0.82 (95% CI = 0.78-0.85) and 0.80 (95% CI = 0.76-0.83) for the CAI and CCE groups. The CAI group had higher sensitivity, DOR, and AUC than the CCE group.

Conclusion

Both of these two groups have good diagnostic accuracy, and CAI/L-AI has a little edge over CCE/L-CEA. However, there is still more research needed to determine whether they can be used as independent indications for secondary orthopedic surgery.Systematic review registration: [https://www.crd.york.ac.uk/PROSPERO/], identifier: [CRD42022338332].

The relationship between gluteus medius and minimus muscle volumes and hip development in developmental dysplasia of the hip

BACKGROUND

Several studies in adult hips have revealed the role of the gluteus medius (Gmed) and gluteus minimus (Gmin) muscles in maintaining the stability and centripetal force of the hip joint. Hip centripetality in developmental dysplasia of the hip (DDH) patients contributes to subsequent healthy hip development later in life. The purpose of this study is to investigate the relationship between Gmed and Gmin volume and centripetality of the hip in infant DDH patients.

METHODS

We retrospectively enrolled 41 unilateral DDH patients (4 males, 37 females) who were treated by closed reduction from 2006 to 2016 and underwent magnetic resonance imaging at around 2 years old. Gmed, and Gmin volume was measured in magnetic resonance imaging. We defined both Gmin and Gmed together as hip abductor gluteus muscles (GMs; Gmed + Gmin). The muscle volume ratio of the affected side was calculated by dividing the GMs volume of the affected side by the contralateral side. Relationships between center-head distance discrepancy (CHDD) at 2 years old, and at 4-6 years old and GMs volume ratio were investigated by Pearson's correlation coefficient within the same patients.

RESULTS

Mean age of closed reduction was 0.8 years old and mean age at MRI was 2.2 years old with a mean follow-up period of 3.7 years. Mean GMs volume in the affected side, contralateral side, and muscle volume ratio were 25.3 cm³, 27.0 cm³, and 0.94, respectively. GMs volumes were significantly higher in the contralateral side (p < 0.001). GMs volume ratio at 2 years old significantly correlated with CHDD at 4-6 years old (p < 0.05).

CONCLUSION

GMs volume at 2 years old was found to be associated with later hip afferents. Promoting the healthy development of GMs by properly maintaining the infant's natural hip movement is important for the healthy hip development.

LEVEL OF EVIDENCE

Level III.

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

BACKGROUND

Although normal anterior acetabular coverage provides stability to the hip, acetabular retroversion leads to femoroacetabular impingement related to hip osteoarthritis. Previous studies have focused on acetabular version and anteroposterior coverage in children with developmental dysplasia of the hip (DDH); however, the correlation between anteroposterior coverage and acetabular development is unclear. We measured anteroposterior acetabular coverage in DDH patients using transverse magnetic resonance imaging (MRI) and subsequent bony acetabular growth, and evaluated the correlation of those findings.

METHODS

We evaluated 37 DDH (dislocations) in 36 patients who underwent MRI at 2 years of age. The mean age was 2.2±0.3 years at the time of MRI (1.6±0.4 y after reduction) and 6.0±0.1 years at the time of plain radiography for the Severin classification. On MRI scans, we measured the cartilaginous center-edge angle (CCEA) and cartilaginous acetabular-head index (CAHI) in the coronal plane and the anterior and posterior cartilaginous center-edge angles (AC-CEA and PC-CEA, respectively) in the transverse plane. Severin I or II was defined as a good outcome and III or IV as a poor outcome.

RESULTS

In the evaluations conducted at 2 years of age, the mean CCEA, CAHI, AC-CEA, and PC-CEA were 14±9 degrees, 66%±10%, 39±8 degrees, and 77±7 degrees, respectively; the CEA at 6 years of age was 13±7 degrees. Twelve and 25 hips were classified in the good and poor outcome groups, respectively. Although CCEA, CAHI, and AC-CEA were significantly associated with the outcome in a single regression analysis ( P <0.05), only AC-CEA was significant in the multiple regression analysis with a stepwise selection method ( P =0.018). The cutoff AC-CEA value for a good outcome was 38 degrees (sensitivity, 67%; specificity, 68%) using a receiver operating characteristic curve.

CONCLUSIONS

Among MRI findings for acetabular cartilaginous morphology, AC-CEA was strongly associated with the outcome. Anteroposterior coverage was correlated with bony acetabular growth in childhood, and anterior coverage was particularly important for subsequent acetabular growth.

LEVEL OF EVIDENCE

Level IV-case series.

Impact of Failed Pavlik Harness Treatment on the Outcomes Following Closed or Open Reduction in Developmental Dysplasia of the Hip

PURPOSE

To investigate the impact of failed Pavlik harness (PH) treatment on the outcomes following closed reduction (CR) or open reduction (OR) in developmental dysplasia of the hip (DDH).

METHODS

Ninety-three DDH patients treated with CR or OR were enrolled. One group of which received previous PH treatment (F group) and the other (L group) not. The clinical outcomes were evaluated according to McKay's criteria. Radiographs were evaluated for acetabular index (AI) and the degree of dislocation of the hips.

RESULTS

A higher rate of CR was found in F group (P = 0.034). Before CR/OR, the mean AI in F group was significantly lower than that in L group (P = 0.000), while at the last follow-up, the AIs in both groups were all improved. In F group, there were 7 (16.67%), 18 (42.86%) and 17 (40.48%) hips were classified as Graf type II, III and IV pathologic changes, respectively, when PH treatment started, while the corresponding data were 17 (40.48%), 17 (40.48%) and 8 (19.05%) after PH treatment (P = 0.024). At the last follow-up, no significant difference was found concerning the complications between the two groups (P > 0.05).

CONCLUSIONS

PH treatment, even if failed, may have the ability of accelerating the development of the acetabulum and increasing the rate of successful CR. Thus we advocate a trial of PH treatment for all DDH patients less than 6 months of age. Meanwhile, a close monitoring by dynamic ultrasonography is required due to the risk of AVN.

MRI Predictors of Residual Dysplasia in Developmental Dysplasia of the Hip Following Open and Closed Reduction

BACKGROUND

Following open or closed reduction for children with developmental dysplasia of the hip, there remains a significant risk of residual acetabular dysplasia which can compromise the long-term health of the hip joint. The purpose of this study was to use postoperative in-spica magnetic resonance imaging (MRI) data to determine factors predictive of residual acetabular dysplasia at short-term follow-up.

METHODS

We retrospectively reviewed 63 hips in 48 patients which underwent closed or open reduction and spica casting for developmental dysplasia of the hip. MRI performed in-spica at ∼3-week follow-up were used to assess 11 validated metrics and 2 subjective factors. Acetabular index (AI) was measured on anteroposterior pelvic radiographs at 2-year postoperative follow-up. Binary logistic regression was then used to identify variables predictive of residual dysplasia, defined as an AI greater than the 90th percentile for age based on historic normative data.

RESULTS

Average age at surgical reduction was 9.3±3.2 months. 58.7% (37/63) of reductions were open. A total of 43 (68.3%) hips demonstrated residual acetabular dysplasia at 2 years postoperatively based on normative values. In those with persistent dysplasia, patients were on average older at the time of reduction (10.0 mo±3.2 vs. 8.0 mo±2.8, P=0.010) and more likely female (88.4% vs. 60.0%, P=0.010). Patients with residual dysplasia were more likely to have mild subluxation on postoperative MRI (40.0% vs. 10.5%, P=0.022). Hips with a cartilaginous acetabular index (CAI) of >23 degrees were 7.6 times more likely to develop residual dysplasia. Type of reduction (ie, closed vs. open) did not appear to influence the rate of residual dysplasia (P=0.682).

CONCLUSION

In this series, the rate of residual dysplasia after surgical reduction was higher than most previous reports, with no appreciable difference between closed and open reductions. Older age, female sex, and a higher CAI were associated with a greater risk of persistent radiographic dysplasia. In particular, hips with a CAI >23 degrees were 7.6 times more likely to be dysplastic at 2-year follow-up.

LEVEL OF EVIDENCE

Level III.

Radiographic Outcomes of Ganz versus Modified Triple Osteotomies in Femoral Head Medialization and Coverage in Acetabular Dysplasia

Variable techniques in periacetabular osteotomy have been formulated for the treatment of acetabular dysplasia. However, few studies have compared the radiographic outcomes between different osteotomy types. This study compared modified triple innominate (MTI) osteotomy and Ganz osteotomy with respect to radiographic outcomes. Patients receiving MTI osteotomies and Ganz osteotomies at any time between 2006 and 2018 in a tertiary medical centre were recruited. Only patients with unilateral osteotomies were recruited to eliminate potential influence from the contralateral hip following periacetabular osteotomy. Patients having hip-joint dislocation, receiving simultaneous proximal femoral osteotomy, or having fewer than 2 years of follow-up were excluded. The radiographic parameters of preoperative and postoperative anteroposterior radiographs of the pelvis were measured, and Sharp’s angle (SA), the lateral centre-edge angle (CE angle), the femoral head extrusion index (FHEI), and the centre-head distance discrepancy (CHDD) were included for comparison. Among 55 participants, 23 received MTI osteotomies and 32 received Ganz osteotomies. The mean age at which patients underwent surgery was 21.9 years in the Ganz osteotomy group and 21.1 years in the MTI group. The mean follow-up length was 2.5 years. The preoperative radiographic parameters between groups differed only slightly and nonsignificantly. Both groups exhibited significantly improved SA, LCEA, and FHEI after surgery. The Ganz osteotomy group exhibited more favourable postoperative FHEI (13.5 vs. 24.3, p < 0.0001), CHDD (3.7 vs. 11.5, p < 0.0001), Sharp angle (45.0 vs. 41.8, p = 0.0489) and CE angles (28.3 vs. 21.1, p = 0.029) compared with the MTI osteotomy group. Notably, CHDD became better and worse following Ganz and MTI osteotomies, respectively; this suggests that the femoral head is pushed laterally in modified triple osteotomy. With respect to femoral head coverage and the medialization of the femoral head, Ganz osteotomy exhibits more favourable corrections in postoperative radiographic parameters than does MTI osteotomy.

Acetabular depth, an early predictive factor of acetabular development: MRI in patients with developmental dysplasia of the hip after open reduction

Early prediction of future acetabular development is important to determine an additional surgery for developmental dysplasia of the hip (DDH). The purpose of this study was to investigate the predictive factors of acetabular development using MRI. We retrospectively investigated dislocated 40 hips and 34 normal hips in 37 pediatric patients (9 males and 28 females) with DDH who underwent open reduction after walking age. We evaluated the cartilaginous acetabulum and labrum of the patients using coronal MRI T2*-weighted images at 5 years of age. The mean age at the time of surgery was 22 months, and the mean age at the final survey was 19 years. We divided patients into two groups in accordance with the Severin classification at the final follow-up. Groups with good outcomes (affected 26 hips and unaffected 27 hips) and poor outcomes (14 hips and 7 hips) were compared using the MRI parameters on each side. Predictive factors of acetabular development were identified using univariate and multiple logistic regression analyses. Using multiple logistic regression analysis, labral acetabular roof depth and labral hip center distance at 5 years of age represented predictors after open reduction (odds ratio 0.27, P = 0.035; odds ratio 3.4, P = 0.028, respectively) on the affected side, and bony hip center distance represented a predictor on the unaffected side (odds ratio 2.6, P = 0.049). Acetabular development in the unaffected side could be predicted by bony assessment, while acetabular development in the affected side had to be assessed by labrum using MRI.

Evaluation of Acetabular Development Following Open Reduction of Developmental Dysplasia of Hip in Children After Walking Age

BACKGROUND AND PURPOSE

The growth and development of the acetabulum in children with developmental dysplasia of hip (DDH) depends upon the extent of concentric reduction. Children in walking age often need open reduction with or without additional osteotomies to obtain congruous, stable reduction. The purpose of this study was to evaluate acetabular development in late diagnosed DDH treated by open reduction with or without femoral osteotomy.

METHODS

This is a retrospective study of 29 children (40 hips) with idiopathic DDH, previously untreated managed by open reduction with or without femoral osteotomy. We analyzed preoperative and yearly postoperative radiographs up to 6 years of age for acetabular development by measuring acetabular index. Acetabular remodeling was assessed with a graphical plot of serial mean acetabular index. Those with AI < 30° at outcome measure point of 6 years of patient age were considered to have satisfactory acetabular remodeling.

RESULTS

Mean age of surgery was 26.8 months. Open reduction alone was done in 14 hips and open reduction with concurrent femoral osteotomy done in 26 hips. The mean acetabular index pre operatively was 36.6° ± 5.9° which reduced to 29.7° ± 6° at 1-year follow-up and to 26.6° ± 5.9° at 2-year follow-up. 28 out of 40 hips were available for evaluation at outcome measure point of 6 years of age, which showed satisfactory remodeling in 24 hips with mean AI of 22.7° ± 5.7°. Maximum acetabular development was seen at 2 years post-surgery and better remodeling was seen in children operated at less than 2 years of age. 5 hips had changes of avascular necrosis of femoral head. There was no incidence of redislocation/subluxation at latest follow-up.

CONCLUSION

Open reduction in late-diagnosed developmental dysplasia of hip has potential for favourable acetabular development. Femoral osteotomy when required along with open reduction may suffice to address acetabular dysplasia found in the initial years of management of DDH.

The fate of inverted limbus in children with developmental dysplasia of the hip: Clinical observation

In this study, we observed the fate of the inverted limbus after closed reduction for the treatment of developmental dysplasia of the hip (DDH) and its impact on acetabular development. Clinical data were reviewed for 26 DDH patients with an inverted or overriding limbus after closed reduction for hip dysplasia. Patients were divided into a residual inversion group (19 cases, 22 hips) and a spontaneous resolution group (7 cases, 7 hips) according to the limbus status at the last follow-up. Differences in the osseous acetabular index (AI) and cartilaginous AI (CAI), the magnitude of limbus inversion, center-edge angle (CEA), height-to-width index (HWI) of the femoral head epiphysis, and avascular necrosis (AVN) at last follow-up were compared. There were no statistically significant differences in the preoperative AI and CAI between groups. The magnitude of limbus inversion after reduction and the AI at the final follow-up in the residual inversion group were both larger than those in the spontaneous resolution group. The CAI, CEA, and HWI were not significantly different between groups. The magnitude of limbus inversion in the residual inversion group did not significantly decrease over time. AVN occurred in five hips in the residual inversion group. No cases of AVN occurred in the spontaneous resolution group. After closed reduction, the inverted limbus was not absorbed in the majority of cases; instead, it evolved into a thin layer of fibrous tissue embedded between the femoral head and acetabulum. This may delay the endochondral ossification of the acetabulum.

Preliminary results of rigid fixation (locking plate/screw) after triple pelvic osteotomy without a hip spica cast: A modified fixation method in 21 patients

Objectives

The aim of this study is to investigate whether rigid fixation after triple pelvic osteotomy (TPO) utilizing a 3.5-mm locking plate and screws without hip spica cast can provide enough stability and prevent correction loss in pediatric patients with developmental dysplasia of the hip (DDH) and Legg-Calvé-Perthes disease (LCPD).

Patients and methods

A total of 21 hips of 21 pediatric patients (9 males, 12 females; mean age: 9.3±2.0 years; range, 6 to 14 years) who underwent rigid fixation with locking plate/screws after TPO for DDH and LCPD between June 2015 and October 2018 were retrospectively analyzed. Preoperative, immediate postoperative, and six-month follow-up anteroposterior radiographs were compared for the Wiberg’s center-edge angle (CE), Sharp angle, acetabular coverage of the femoral head (ACFH), and center-head distance discrepancy (CHDD). The patient demographics, surgery time, perioperative complications were evaluated.

Results

Underlying diagnosis were DDH in 14 patients and LCPD in seven patients. In patients with DDH, postoperative evaluation showed significant increase in the mean CE angle (5.6±16.1° vs. 30.5±9.3°, respectively) and ACFH (46.4±16.8% vs. 84.5±12.1%, respectively), and a significant decrease in the mean Sharp angle (55.3±6.2° vs. 35.6±7.8°, respectively) and CHDD (14.6±10.7% vs. 6.2±5.6%, respectively). The final follow-up revealed that there was no correction loss in these parameters. In the patients with LCPD, postoperative evaluation showed a significant increase in the mean CE (20.1±11.1° vs. 38.3±9.6°, respectively) and ACFH (62.9±18% vs. 91.4±10.1%, respectively), and a significant decrease in the mean Sharp angle (46±3.6° vs. 25.2±5.5°, respectively). The final follow-up revealed that there was no correction loss in radiological parameters. No perioperative complications were noted.

Conclusion

Our study results suggest that rigid fixation construct with a 3.5-mm locking plate and screws without hip spica cast can provide adequate stability to allow early mobilization following TPO in children without any loss of correction, until bony healing at the osteotomy sites.

Clinical and radiological outcomes of combined acetabuloplasty with acetabular redirectional osteotomy and femoral shortening for children older than 9 years of age with developmental dysplasia of the hip: a retrospective case series

Developmental dysplasia of the hip (DDH) is a challenging pediatric condition. This study aimed to investigate the feasibility and the efficacy of Dega osteotomy in combination with pelvic triple osteotomy or periacetabular osteotomy and femoral shortening with derotational osteotomy for the treatment of severe acetabular deformity secondary to DDH in children older than 9 years of age. The clinical data of 22 children treated at our institution were retrospectively collected. Pre- and postoperative hip radiographs were evaluated. Center-edge (CE) angle was measured, and Severin classification and McKay criteria were used to evaluate the final outcome. Twenty-two patients (including 21 female patients) were treated during the study period. The mean age was 10.9 years (range 9.1-14.8). All patients had preoperative Tonnis grades III and IV dislocated hips. Mean follow-up time was 25.7 months (range 14-48). All but three hips underwent open reduction. All had concomitant proximal femoral shortening and derotation osteotomy. At last follow-up visit, all hips remained located and no cases of avascular necrosis were recorded. All patients had Severin grade I-II hips at last follow-up. According to McKay criteria, clinical outcome was excellent in three patients, good in seven, and fair in 12 patients. Acetabuloplasty in combination with periacetabular osteotomy and femoral shortening with derotational osteotomy is a valid and effective treatment for children older than 9 years of age with severe acetabular deformity secondary to DDH. Although the early clinical outcome of the reported procedure is favorable, further studies are necessary to evaluate the long-term effects of the reported technique.

Evolution of concentricity after closed reduction in developmental dysplasia of the hip

AIMS

The goal of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) is to achieve and maintain concentricity of the femoral head in the acetabulum. However, concentric reduction is not immediately attainable in all hips and it remains controversial to what degree a non-concentric reduction is acceptable. This prospective study is aimed at investigating the dynamic evolution of the hip joint space after CR in DDH using MRI.

METHODS

A consecutive series of patients with DDH who underwent CR since March 2014 were studied. Once the safety and stability were deemed adequate intraoperatively, reduction was accepted regardless of concentricity. Concentricity was defined when the superior joint space (SJS) and medial joint space (MJS) were both less than 2 mm, based on MRI. A total of 30 children, six boys and 24 girls, involving 35 hips, were recruited for the study. The mean age at CR was 13.7 months (3.5 to 27.6) and the mean follow-up was 49.5 months (approximately four years) (37 to 60). The joint space was evaluated along with the interval between the inverted and everted limbus.

RESULTS

Only three hips (8.6%) were fully concentric immediately after CR. During follow-up, 24 hips (68.6%) and 27 hips (77.1%) became concentric at six months and one year, respectively. Immediate SJS after CR decreased from 3.51 mm to 0.79 mm at six months follow-up (p = 0.001). SJS in the inverted group decreased from 3.75 mm to 0.97 mm at six months follow-up. SJS or MJS in the everted group were less than those in the inverted group at each time of follow-up (p = 0.008, p = 0.002).

CONCLUSION

A stable, safe but non-concentric reduction achieved before the age of two years appears to improve over time with nearly 80% of hips becoming fully concentric by one year. Cite this article: Bone Joint J 2020;102-B(5):618-626.

Does Adductor Tenotomy Need During Closed Reduction Have a Prognostic Value in the Treatment of Developmental Dysplasia of the Hip Between 6 and 12 Months of Age? "Adductor Tenotomy in the Treatment of Developmental Dysplasia''

BACKGROUND

Adductor tenotomy is needed for clinically complex hips with soft-tissue contractures. It may be proposed that the patients who need adductor tenotomy during closed reduction would have poorer prognosis than the ones without need for adductor tenotomy. The main purposes were to compare the normalization of acetabular index angle (AI), to determine the incidence of femoral head avascular necrosis (AVN), and to predict the need for any secondary surgical intervention between the patients who need adductor tenotomy and those who do not during closed reduction for developmental dysplasia of the hip.

MATERIALS AND METHODS

The study group consisted of 65 hips treated between 6 and 12 months of age. The mean age at the time of surgery was 8.1 ± 1.4 (6-12) months and the mean follow-up was 4.2 ± 1.5 years. Improvement of AI, rate and severity of AVN, and need for secondary surgery with its predictors were evaluated.

RESULTS

Adductor tenotomy was performed in 22 hips (Group 1), but not in 43 hips (Group 2). Normalization of the AI was - 14.8° ± 3.5° versus - 14.3° ± 3.2°. The overall incidence of AVN was 18.4%. The rate of secondary surgical intervention was higher in Group 1 (63.1% versus 36.9%) (p = 0.014).

CONCLUSIONS

No significant difference was detected regarding the improvement of AI as well as the incidence of AVN between the groups. The need for adductor tenotomy during closed reduction was one of the main predictors of the possible secondary surgery.

How to judge pelvic malposition when assessing acetabular index in children? Three simple parameters can determine acceptability

BACKGROUND

The acetabular index (AI) is the most commonly used parameter for diagnosing hip dysplasia. Pelvic malposition can result in misinterpretation of AI measurement especially in younger children. We aimed to investigate the correlation between pelvic orientation and acetabular index (AI) by using digital reconstructed radiographs (DRRs) and identify reliable parameters predictive of pelvic orientation on plain radiographs.

METHODS

We retrospectively identified 33 children (52 hips) who received dual source CT examinations. Virtual pelvic models were reconstructed after scanning. After orientating in the standard neutral position, the models were rotated and tilted around corresponding axes. DRRs were generated at every 3° during the process. The acetabular index, the horizontal diameter (Dh) and vertical diameter (Dv) of bilateral obturator foramina, the vertical distance (h) between upper border of pubic symphysis, and Hilgenreiner's line were measured on each DRR by two independent observers. Rotation index (Rr = right Dh/left Dh), tilt index (Rt = h/Dv), intra-observer error, and inter-observer error of AI were calculated.

RESULTS

For tilt and rotation up to 12.0°, AI increased with anterior tilt and decreased with posterior tilt. And for rotation, it increased on the side toward which the pelvis rotated and decreased on the opposite side. AI varied dramatically if angulation exceeded 6.0°. Malposition below this limit demonstrated the intra- and inter-observer errors were ± 2.0° and ± 3.0° respectively and caused no significant effect on AI measurement.

CONCLUSIONS

For children up to age 6 years, an acceptable pelvic plain radiograph can be determined when Rt is approximately between 0.9 and 1.4 and Rr between 0.7 and 1.5. For the first time, we have identified parameters derived from a group of subjects which can predict this degree of malposition. The parameters obturator diameters (Dh), obturator height (Dv), and distance (h) between symphysis and Hilgengreiner's line can be feasibly measured on X-ray and employed in clinical practice to assess the acceptability of the pediatric pelvic radiograph prior to measurement of the AI.

Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling

BACKGROUND

This study aims to assess acetabular remodeling following closed vs, open hip reduction in children younger than 2 years of age.

METHODS

Records of children with DDH, who underwent closed or open reduction, were reviewed. Acetabular index (AI) was measured on radiographs taken prior to reduction and on outcome radiographs taken at age 4 years. Radiographic outcomes were analyzed and residual dysplasia (outcome AI ≥ 30) degrees recorded.

RESULTS

42 hips had closed reduction; and 26 hips had open reduction. A higher percentage of hips treated with successful closed reduction, had outcome AI ≥ 30° (29% vs. 19% p = 0.387). Residual dysplasia was more common in IHDI-IV hips than IHDI-III hips for both groups. A higher incidence of AVN was seen in the open reduction group (13% vs. 7%; p = 0.43).

CONCLUSION

In children with DDH under the age of two, open reduction with capsulorrhaphy may benefit acetabular remodeling more so than closed reduction despite maintenance of reduction. Although AVN remains a risk, higher remodeling might be expected with open reduction.

Treatment of developmental dysplasia of the hip (DDH) between the age of 18 and 24 months

BACKGROUND

Treatment of developmental dysplasia of the hip between the age of 6 and 18 months starts with closed reduction (CR). If CR is not attainable, open reduction is performed. Open reduction and pelvic osteotomy (ORPO) is usually done directly after the age of two. The aim of this study is to evaluate CR compared to ORPO with respect to early radiographic outcome in patients aged 18 to 24 months at reduction.

METHODS

A single-surgeon cohort was reviewed. Inclusion criteria were age between 18 and 24 months, no prior treatment and minimal follow-up of 2 years. Hips that were not displaced or had a nonidiopathic cause were excluded. Residual dysplasia was defined as a center edge angle (CEA) of less than 15° or CEA less than 20° with an acetabular index (AI) of more than 30°. Multiple regression was used, the outcome was follow-up CEA, and the explanatory variables were age, sex, type of surgery, international hip dysplasia grade and preoperative AI. Values of preoperative AI in the CR group and follow-up CEA were plotted.

RESULTS

Eighty-two hips in fifty patients were included. Residual dysplasia was identified in 16 hips (20%), 12 (27%) after CR, and 4 (11%) after ORPO (p = 0.10). Recurrence and avascular necrosis rates were not statistically different. Preoperative AI and type of surgery independently affected CEA. CR patients with a preoperative AI of more the 40° had a 50% (10/20) risk of residual dysplasia.

CONCLUSION

CR is an important option to consider in selected patients between the age of 18 and 24 months and the selection should not be based on intraoperative assessment only, but also on preoperative measurement of AI.

LEVEL OF EVIDENCE

Level III.

Overgrowth of the lower limb after treatment of developmental dysplasia of the hip: incidence and risk factors in 101 children with a mean follow-up of 15 years

Background and purpose - There are few studies on overgrowth of the affected limb after treatment of developmental dysplasia of the hip (DDH). We investigated the incidence of overgrowth and its risk factors in DDH patients.Patients and methods - 101 patients were included in this study. Overgrowth was defined by 2 criteria: when the height of the femoral head of the affected side was higher than that of the contralateral side by more than 10 mm, or by more than 15 mm. The potential risk factors of distinct overgrowth were retrospectively examined using multivariable analysis.Results - When overgrowth was defined as femoral head height difference (FHHD) > 10 mm, its incidence was 44%, and only femoral osteotomy was identified as a significant risk factor with a relative risk (RR) of 1.6 (95% confidence interval [CI] 1.0-2.5). When overgrowth was defined as FHHD > 15 mm, its incidence was 23%, and femoral osteotomy was identified as the only significant risk factor with an RR of 2.3 (CI 1.2-4.5). Overgrowth developed more frequently in patients who underwent femoral osteotomy at the age of 2 to 4 years (87%) than in the others (46%) (p = 0.04).Interpretation - Overgrowth of the affected limb is common in DDH patients. Patients who underwent femoral osteotomy, especially at the age of 2 to 4 years, may require careful follow-up because of the substantial risk for overgrowth.

Comparison of arthroscopic and open reduction of conservatively irreducible dislocated hips of children

PURPOSE

Children with sonographic grade IV hip dysplasia according to Graf and with failed conservative treatment usually need surgical reduction afterwards. Surgical reduction of the hip can lead to severe complications, the occurrence of residual acetabular dysplasia, osteonecrosis, redislocation and other postoperative complications. This paper investigates whether arthroscopic reduction is a promising alternative to open reduction.

METHODS

We retrospectively examined 66 patients (78 hips) who were not older than two years at the first time of surgery. Arthroscopic reduction was performed on 17 children (19 hips) and open reduction on 49 children (59 hips). Patient records were used to determine redislocation, postoperative complication and residual dysplasia. Radiographs were used to determine Tönnis classification for osteonecrosis and pathological acetabular (AC) angle for residual dysplasia. We considered data up to a two-year follow-up. Statistical evaluation was performed with binary logistic regression.

RESULTS

After arthroscopic reduction, 6% showed osteonecrosis, compared with 20% with open reduction (p = 0.334). Redislocation was not observed after arthroscopic reduction but for 29% after open reduction (p = 0.005). An improvement of femoral head coverage was achieved with residual dysplasia of 23.5% after arthroscopic reduction, compared with 62% after open reduction (p = 0.002).

CONCLUSION

The arthroscopic procedure represents a meaningful alternative to the open procedure due to a lower complication rate, a safe setting, a lower rate of residual dysplasia, no observed redislocation and occurrence of osteonecrosis only once in the arthroscopic group of developmental dysplasia of the hip. The arthroscopic procedure should be tested in further studies and in other clinics in order to broaden the empirical base.

LEVEL OF EVIDENCE

Level III (retrospective cohort study).

Predicting acetabular growth in developmental dysplasia of the hip following open reduction after walking age

BACKGROUND

Acetabular dysplasia of the hip following open reduction can complicate the treatment of developmental dysplasia of the hip (DDH). The purposes of this retrospective study were to investigate the long-term results of open reduction performed via an extensive anterolateral approach for DDH after walking age and to predict acetabular development using postoperative radiographs and arthrograms.

METHODS

From 1973 to 2001, we performed open reduction for 131 hips in 119 pediatric patients with DDH after failed closed reduction. Of these, 85 hips of 73 patients who underwent arthrography at 5 years old were followed-up radiologically until skeletal maturity. Mean age at the time of surgery was 17 ± 4.6 months (range, 10-33 months), and mean age at final survey was 19 ± 5.7 years (range, 14-33 years). Mean follow-up time was 17.7 ± 5.8 years (range, 13-32 years). Groups with satisfactory outcomes (66 hips) and unsatisfactory outcomes (19 hips) according to the Severin classification were compared. Factors predicting acetabular development were identified using univariate and multiple logistic analyses.

RESULTS

Univariate analysis showed a significant between-group difference in acetabular index (AI) at 2 months postoperatively, and in center-edge (CE) angle, cartilaginous AI (CAI), and cartilaginous CE angle at 5 years old (p < 0.05 each). In multiple logistic regression analysis, CAI at 5 years old represented a predictor of acetabular development after open reduction for DDH (odds ratio, 1.81; 95% confidence interval (CI), 1.04-3.13; p < 0.05). Area under the receiver operating characteristic curve for CAI at 5 years old was 0.93 (95%CI, 0.85-1.0), and the optimal cut-off was 10° (81.8% sensitivity, 92% specificity).

CONCLUSIONS

A CAI ≥10° on hip arthrograms at 5 years old may offer a useful indicator of the need for corrective surgery following open reduction after walking age.

Prognostication in Developmental Dysplasia of the Hip Using the Ossific Nucleus Center Edge Angle

BACKGROUND

The aim of this paper was to determine the prognostic potential of the ossific nucleus center edge angle (ONCEA) in patients below 5 years of age treated for developmental dysplasia of the hip (DDH) to predict final outcome and the need for a secondary procedure.

METHODS

The interobserver and intraobserver reliability was calculated using the intraclass correlation coefficient for measurement of the ONCEA. The ONCEA was divided a priori into 3 groups: group A≥10 degrees, group B -9 to 9 degrees, and group C ≤-10 degrees. Final outcome was measured using the McKay score and Severin classification. The presence of osteonecrosis was recorded at final follow-up.

RESULTS

One hundred one patients with 133 dislocated hips underwent closed or open reduction for DDH. Mean age at presentation was 19 months with a mean age at final follow-up of 12.4 years. A significant difference was shown in a comparison of the 3 ONCEA groups using the McKay score, Severin classification, and need for a secondary procedure. Eighty seven of the 101 patients underwent ONCEA reliability measurements. The ONCEA was shown to have a mean intrarater reliability of 0.89, and a mean interrater reliability of 0.77.

CONCLUSIONS

The ONCEA is a reliable measurement in predicting medium-term outcome of the hip post reduction in children under the age of 5 years with DDH and might be useful as a predictor for a secondary procedure before the age of 5 years.

LEVEL OF EVIDENCE

Level III-prognostic case control study.

CLINICAL RELEVANCE

This case control study shows the importance of measuring the ONCEA within 6 months of removing the final cast after reduction of a dislocated hip and its implications for further management and outcome.

Acetabular index is the best predictor of late residual acetabular dysplasia after closed reduction in developmental dysplasia of the hip

PURPOSE

Our objective was to find the best predictor of late residual acetabular dysplasia in developmental dysplasia of the hip (DDH) after closed reduction (CR) and discuss the indications for secondary surgery.

METHODS

We retrospectively reviewed the records of 89 patients with DDH (mean age 16.1 ± 4.6 months; 99 hips) who were treated by CR. Hips were divided into three groups according to final outcomes: satisfactory, unsatisfactory and operation. The changes in the acetabular index (AI), centre-edge angle of Wiberg (CEA), Reimer's index (RI) and centre-head distance discrepancy (CHDD) over time among groups were compared. The power of predictors for late residual acetabular dysplasia of AI, CEA, RI and CHDD at different time points was analysed by logistic regression analysis. Receiver operating characteristics (ROC) curve analysis was used to determine cutoff values and corresponding sensitivity, specificity and diagnostic accuracy for these parameters.

RESULTS

Both AI and CEA improved in all groups of patients following CR. In the satisfactory group, AI progressively decreased until seven to eight years, while CEA increased until nine to ten years (P < 0.05). In the unsatisfactory group, AI and CEA ceased to improve three and two years after CR, respectively (P < 0.05). CEA and RI were significantly better in the satisfactory group compared with the unsatisfactory group at all time points (P < 0.05). Following CR, both RI and CHDD remained stable over time in all groups. Final outcome following CR could be predicted by AI, CEA and RI at all time points (P < 0.01). Cutoff values of AI, CEA and RI were 28.4°, 13.9° and 34.5%, respectively, at one year and 25°, 20° and 27%, respectively, at two to four years post-CR. A total of 80-88% of hips had an unsatisfactory outcome if AI > 28.4° and >25 at one and two to four years following CR, respectively. However, if CEA was less than or RI was larger than the cutoff values at each time point, only 40-60% of hips had an unsatisfactory outcome. Mean sensitivity (0.889), specificity (0.933) and diagnostic accuracy (92.1%) of AI to predict an unsatisfactory outcome were significantly better compared with CEA (0.731; 0.904; 78.2%) and RI (0.8; 0.655; 70.8%) (P < 0.05).

CONCLUSIONS

Satisfactory and unsatisfactory hips show different patterns of acetabular development after reduction. AI, CEA and RI are all predictors of final radiographic outcomes in DDH treated by CR, although AI showed the best results. AI continues to improve until seven years after CR in hips with satisfactory outcomes, while it ceases to improve three to four years after CR in hips with unsatisfactory outcomes. According to our results, surgery is indicated if AI >28° 1 year following CR or AI >25° two to four years after CR. CEA and RI should be used as a secondary index to aid in the selection of patients requiring surgery.

Percutaneous medial hemi-epiphysiodesis using a transphyseal screw for caput valgum associated with developmental dysplasia of the hip

Background

The purpose of this study was to evaluate the radiologic outcome of percutaneous medial hemi-epiphysiodesis using a transphyseal screw for the management of caput valgum associated with developmental dysplasia of the hip (DDH).

Methods

Eighteen hips (18 patients) having caput valgum treated with screw hemi-epiphysiodesis were followed for more than 2 years, and were included in this study. The mean age at the time of the index operation was 8.3 years (range, 4.3 to 10.7 years) and age at the latest follow-up was 12.2 years (range, 9.4 to 16.4 years). The screw in 5 hips was changed into a longer one at postoperative 21.8 months (range, 14 to 29 months) because the proximal femur outgrew the screw. The screws in 11 hips were removed at the mean age of 10.9 years (range, 8.0 to 14.5 years). We retrospectively analyzed the change in various radiologic parameters over time.

Results

The mean Hilgenreiner-epiphyseal angle (HEA) of the operated side was 5.1 ± 11.3° preoperatively, and increased to 20.6 ± 11.3° at the latest follow-up (p = 0.001). The mean difference of the HEA between the operated and contralateral sides was 16.9 ± 15.1° preoperatively, which decreased to 2.4 ± 12.4° at the latest follow-up (p = 0.008). The mean articulo-trochanteric distance of the operated side, which was 3.2 ± 5.5 mm longer than that of the contralateral side preoperatively, became 5.6 ± 9.1 mm shorter at the latest follow-up (p = 0.001). The ratio of femoral neck length of the operated side to that of the contralateral side decreased over the follow-up period. Acetabular shape as measured by the Sharp angle and acetabular roof angle and femoral head coverage as measured by lateral center-edge angle did not change significantly by the index operation. The ratio of medial joint space width of the operated side to that of the contralateral side did not change significantly.

Conclusions

Screw medial hemi-epiphysiodesis can effectively correct caput valgum associated with DDH. However, this technique remains coxa brevis and does not seem to significantly affect acetabular morphology or reduce subluxation.

The correlation between Salter's criteria for avascular necrosis of the femoral head and Kalamchi's prognostic classification following the treatment of developmental dysplasia of the hip

AIMS

The aim of this study was to evaluate the correlation between Salter's criteria and Kalamchi's classification of avascular necrosis in patients treated for developmental dysphasia of the hip (DDH).

PATIENTS AND METHODS

The study involved a retrospective analysis of 123 patients (123 hips) with DDH treated by operative and non-operative reduction before the age of two years, with a minimum follow-up of ten years. Salter's criteria (S1 to S4) were determined from radiographs obtained at one to two years post-reduction, whilst the Kalamchi grade was determined from radiographs obtained at ten or more years of age. Early post-reduction radiographs were also used to evaluate the centre-head distance discrepancy (CHDD) and the occurrence of a dome-shaped deformity of the proximal femoral metaphysis (D-shaped metaphysis). The prognosis was described as good (Kalamchi grade K0 or KI), fair (Kalamchi grade KII) or poor (Kalamchi grade KIII or KIV) for analysis and correlation with the early Salter criteria, CHDD and D-shaped metaphysis.

RESULTS

S1 and S2 criteria were predictive of a poor prognosis. The outcome following S3, S4 and S3 + S4 varied; 18 (40%) had a good prognosis, 17 (38%) a fair prognosis and ten (22%) a poor prognosis. A CHDD ≥ 10% and a D-shaped metaphysis were also predictive of a poor prognosis.

CONCLUSION

The Salter criteria were predictive of the Kalamchi grade of avascular necrosis in patients with DDH aged ten or more years after reduction of the hip. Cite this article: Bone Joint J 2017;99-B:1115-20.

The management of residual acetabular dysplasia: updates and controversies

Residual acetabular dysplasia is a frequent cause of secondary osteoarthritis of the hip and its management is still controversial. The aim of this review is to describe residual acetabular dysplasia, to estimate the age limit above which surgical management is needed, and to emphasize the role of assistive imaging in evaluating predictive parameters for future acetabular development. A decision-making algorithm is presented.

The Fate of DDH Hips Showing Cartilaginous or Fibrous Tissue-filled Joint Spaces Following Primary Reduction

BACKGROUND

Because the use of magnetic resonance imaging is still not universal for the patients with developmental dysplasia of the hip patients, orthopaedists do not generally distinguish widened joint spaces which are "empty" after primary treatment (and therefore still reducible), from those which are filled and much more difficult to treat. To date no studies have focused on the latter hips. We treated and observed the outcomes for 19 hips which showed filled joint spaces after primary treatment.

METHODS

We retrospectively reviewed 19 cases of developmental dysplasia of the hip: (1) who showed a widened joint space on radiographs after primary treatment; and (2) whose magnetic resonance imaging showed that the widened joint space was accompanied by acetabular cartilage hypertrophy and/or was filled with fibrous tissues. All patients were over 1 year old at the time of primary reduction (reduction was closed in 4 patients, open in 6, and open with pelvic osteotomy in 9). Thirteen patients received at least 1 secondary treatment. Final results were classified using a modified Severin classification.

RESULTS

Final outcomes were satisfactory in 10 (52.6%) and unsatisfactory in 9 (47.4%). The widened joint spaces gradually filled with bone, resulting in a shallow acetabulum in the patients with unsatisfactory results. Of 9 patients who underwent combined pelvic osteotomy at the time of primary reduction, results were satisfactory in 6 (66.7%), whereas all patients who had only closed or open primary reduction had unsatisfactory results.

CONCLUSIONS

Combined pelvic osteotomy at the time of primary reduction is advisable in hips with widened joint spaces. However, hips with filled joint spaces after primary treatment often have unsatisfactory results even after additional pelvic and/or femoral osteotomy.

LEVEL OF EVIDENCE

Level IV-prognostic study.

Acetabular development after open reduction to treat dislocation of the hip after walking age

BACKGROUND

Treatment of hip dislocation diagnosed after walking age is often difficult. We report the surgical treatment of these patients by open reduction with a soft tissue surgical procedure without osteotomy.

METHODS

Thirty-eight children (43 hips) diagnosed with complete dislocation of the hip after walking age were included in this study. We radiographically analysed postoperative hip joint development up to 6 years of age. To assess the predictors of acetabular development, we evaluated the radiographs, using an acetabular index of ≤35° and a centre-edge angle of >5° at 6 years of age as satisfactory outcomes, and evaluated the advance of acetabular development over time.

RESULTS

AI on the affected side was improved with time after open reduction. The diameter of the capital femoral ossific nucleus on the affected side was almost equivalent to that on the unaffected side at 6-12 months after surgery, after which the centre-edge angle improved gradually from one year after surgery. We compared hips classified as satisfactory to unsatisfactory at 6 years of age, and found that the centre-edge angle at one year after open reduction was significantly associated with acetabular development (P = 0.044). The cut-off value was -2° with sensitivity of 0.909 and specificity of 0.677.

CONCLUSIONS

The results of the current study suggest that initial development of the capital femoral ossific nucleus after open reduction would be followed by improved joint congruity, and that this would facilitate acetabular development. The centre-edge angle at one year after surgery could be regarded as a potential predictor of acetabular development in open reduction surgery for late-diagnosed developmental dysplasia of the hip cases.

Acetabular Remodeling and Role of Osteotomy After Closed Reduction of Developmental Dysplasia of the Hip

BACKGROUND

The purposes of this study were to evaluate acetabular remodeling after closed reduction of developmental dysplasia of the hip (DDH) and to delineate the role of osteotomy.

METHODS

Eighty-four hips with DDH treated with closed reduction and followed until the patient was 8 years of age or older were included in this study. The mean age at closed reduction was 14.0 months (range, 3 to 30 months) and that at the latest follow-up visit was 12.7 years (range, 8.0 to 24.7 years). Osteotomy was performed in 26 hips (31%) during the follow-up period, at an average age of 2.8 years (range, 2.0 to 5.8 years). The acetabular index (AI) and center-edge angle (CEA) were measured, and osteonecrosis was graded. The treatment outcome was evaluated as satisfactory (Severin grade I or II) or unsatisfactory (III or IV). We retrospectively analyzed the associations among radiographic parameters, performance of osteotomy, grade of osteonecrosis, and final outcome.

RESULTS

A satisfactory outcome was observed in 67 (80%) of the 84 hips. An osteotomy was not performed in 30 of 34 hips with an AI of <32° and a CEA of >14° at the age of 3 years, and 28 (93%) of these 30 hips showed a satisfactory outcome. Of the 33 hips with an AI of ≥32° and a CEA of ≤14° at the age of 3 years, the 20 that had undergone an osteotomy showed a higher proportion of satisfactory outcomes than the 13 hips that had not (p = 0.01). Three of the 4 hips that showed an unsatisfactory outcome following an osteotomy had an AI of ≥34° at 1 year post-osteotomy. Grade-II, III, or IV osteonecrosis, according to the Bucholz-Ogden classification, developed in 10 of the 84 hips, and these 10 hips had a higher proportion of unsatisfactory outcomes than did those that developed no or grade-I osteonecrosis (p = 0.004).

CONCLUSIONS

Hips with DDH showing poor acetabular remodeling after closed reduction may benefit from osteotomy. The AI and CEA at the age of 3 years can serve as one of the guidelines for osteotomy. Continued surveillance for acetabular remodeling is required even after osteotomy.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Risk factors for avascular necrosis after closed reduction for developmental dysplasia of the hip

PURPOSE

The purpose of this study was to identify and evaluate risk factors of avascular necrosis (AVN) after closed treatment for developmental dysplasia of the hip (DDH).

METHODS

A retrospective review of children diagnosed with DDH at a tertiary-care children's hospital between 1986 and 2009 was performed. The presence of AVN was assessed according to Salter's classification system.

RESULTS

Eighty-two affected hips in 70 children with an average age of 10 months at closed reduction (range 1-31 months) and 5 years (range 2-19 years) of follow-up met the inclusion criteria. Twenty-nine (of 82, 35 %) affected hips developed AVN. The use of pre-reduction traction (p = 0.019) increased the risk of AVN, while preoperative Pavlik harness or brace trial (p = 0.28), presence of ossific nucleus at the time of closed reduction (p = 0.16), and adductor tenotomy (p = 0.37) were not significant factors. Laterality (right vs. left) was also not a significant risk factor (p = 0.75), but patients who underwent closed reduction for bilateral DDH were less likely to develop AVN (p = 0.027). Overall, the degree of abduction did not affect the rate of AVN (p = 0.87). However, in patients treated with closed reduction younger than 6 months of age, the rate of AVN was increased with abduction ≥50° (9/15, 60 %) compared to abduction <50° (0/8, 0 %) (p = 0.007). Patients who developed AVN were more likely to require subsequent surgery (p = 0.034) and more likely to report a fair/poor clinical outcome (p = 0.049).

CONCLUSIONS

The risk of AVN (35 %) following closed reduction and spica casting for DDH is high. The degree of abduction in spica casts appears to be a risk factor in patients ≤6 months old. The authors recommend that abduction in spica casts should be limited to <50° in children younger than 6 months of age.

LEVEL OF EVIDENCE

IV.

A new predictive indicator by arthrography for future acetabular growth following conservative treatment of developmental dysplasia of the hip

The aim of this study was to find a new predictive indicator for acetabular growth of developmental dysplasia of the hip. Seventy-three hips that were diagnosed with developmental dysplasia of the hip and treated by conservative reduction were included in our study. In 30 hips with center-edge angle ≤ 10° at age 4, the center-edge of the acetabular limbus angle (CEALA) in the arthrogram was measured. On the basis of the results, CEALA was significantly smaller in the secondary acetabular dysplasia group than in the normal group at maturity. In conclusion, CEALA is a more reliable and accurate predictive indicator for acetabular development than center-edge angle or acetabular index.

Prognostic radiographic factors in developmental dysplasia of the hip following Salter osteotomy

Radiographic parameters for evaluating hip development are altered by Salter osteotomy, and their prognostic value require further validation. A total of 63 patients who underwent open reduction and Salter osteotomy for unilateral hip dysplasia were evaluated with Severin classification 10.8 years later. The initial first-year postoperative acetabular index, c/b ratio, head-teardrop distance, and head coverage were compared with the final outcome of Severin classification. Greater c/b ratio was significantly associated with later Severin class III hip. Using receiver operating characteristics curve, a c/b ratio greater than 0.72 at 6 months and 1 year postoperatively can predict the possibility of a class III hip in 30 and 60% of patients, respectively.

Medial versus anterior open reduction for developmental hip dislocation in age-matched patients

BACKGROUND

The difference between medial (MAOR) and anterior (AAOR) approaches for open reduction of developmental hip dysplasia in terms of risk for avascular necrosis (AVN) and need for further corrective surgery (FCS, femoral and/or acetabular osteotomy) is unclear. This study compared age-matched cohorts undergoing either MAOR or AAOR in terms of these 2 primary outcomes. Prognostic impact of presence of ossific nucleus at time of open reduction was also investigated.

METHODS

Institutional review board approval was obtained. Nineteen hips (14 patients) managed by MAOR were matched with 19 hips (18 patients) managed by AAOR based on age at operation (mean 6.0; range, 1.4 to 14.9 mo). Patients with neuromuscular conditions and known connective tissue disorders were excluded. Primary outcomes assessed at minimum 2 years' follow-up included radiographic evidence of AVN (Kalamchi and MacEwen) or requiring FCS.

RESULTS

MAOR and AAOR cohorts were similar regarding age at open reduction, sex, laterality, and follow-up duration. One hip in each group had AVN before open reduction thus were excluded from AVN analysis. At minimum 2 years postoperatively (mean 6.2; range, 1.8 to 11.7 y), 4/18 (22%) MAOR and 5/18 (28%) AAOR met the same criteria for AVN (P=1.0). No predictors of AVN could be identified by regression analysis. Presence of an ossific nucleus preoperatively was not a protective factor from AVN (P=0.27). FCS was required in 4/19 (21%) MAOR and 7/19 (37%) AAOR hips (P=0.48). However, 7/12 (54%) hips failing closed reduction required FCS compared with 4/26 (16%) hips without prior failed closed reduction (P=0.024). Cox regression analysis showed that patients who failed closed reduction had an annual risk of requiring FCS approximately 6 times that of patients without a history of failed closed reduction (hazard ratio=6.1; 95% CI, 1.5-24.4; P=0.009), independent of surgical approach (P=0.55) or length of follow-up (P=0.78).

CONCLUSIONS

In this study of age-matched patients undergoing either MAOR or AAOR, we found no association between surgical approach and risk of AVN or FCS. In addition, we identified no protective benefit of a preoperative ossific nucleus in terms of development of AVN. However, failing closed reduction was associated with a 6-fold increased annual risk of requiring FCS.

SIGNIFICANCE

To the best of our knowledge, this is the first study comparing these 2 surgical techniques in an age-matched manner. It further corroborates previous studies stating that there may be no difference in risk of AVN based on surgical approach or presence of ossific nucleus preoperatively.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

International variance in the treatment of developmental dysplasia of the hip

INTRODUCTION

Developmental dysplasia of the hip (DDH) is the most common congenital musculoskeletal abnormality. Recourse to definitive surgical treatment is not typically taken until over the age of 18-24 months. International consensus regarding age at surgery, degree of dysplasia requiring surgery and type of osteotomy is not available in the literature.

STUDY AIMS

To determine variation in timing and type of osteotomy for persistent DDH across the world.

METHODOLOGY

Senior authors of recent publications pertaining to hip dysplasia were sampled. Participants' practice relating to age and radiological indications for surgery were determined.

RESULTS

Thirty-two surgeons responded from five different geographical regions. No inter-regional consensus was established regarding investigations to determine the need for osteotomy, preferred osteotomy type or ideal age at which to perform an osteotomy.

CONCLUSION

International agreement regarding the surgical management of DDH does not exist. This common congenital condition warrants development of a treatment algorithm.

Abduction bracing for residual acetabular dysplasia in infantile DDH

BACKGROUND

Abduction bracing is often used to treat residual acetabular dysplasia in infants whose acetabular indices (AI) exceed 30 degrees after 6 months of age. However, little data exist to support this practice. The purpose of this study was to determine the efficacy of part-time abduction bracing in treating residual acetabular dysplasia by comparing a cohort of braced infants with a cohort of unbraced infants.

METHODS

We performed a retrospective review of a consecutive series of patients with developmental dysplasia of the hip (DDH) treated at our institution over 4 years. Children with stable, treated DDH but residual acetabular dysplasia at 6 months of age were identified; those with available anteroposterior pelvic radiographs at 6 months and 1 year of age were included. Patients who required open surgical reduction and those with syndromic or neuromuscular diagnoses were excluded. On the basis of practice variations at our institution, some orthopaedists start bracing when the 6-month radiograph demonstrates an AI≥30 degrees, whereas others do not; we compared these 2 cohorts. Braced patients were instructed to wear an abduction orthosis during nights and naps until follow-up at 1 year of age. The AI at 6 months and 1 year of age for both cohorts were then measured by a single observer and the differences compared.

RESULTS

Seventy-six hips in 52 patients were identified with residual dysplasia on the 6-month radiograph. Thirty-nine hips (27 patients) were unbraced, 31 hips (21 patients) were braced, and 6 hips (4 patients) were excluded for cross-over. Over a 6-month period, the braced cohort had significantly better improvement in the AI of 5.3 degrees (95% confidence interval, 4.3 to 6.3 degrees) compared to the unbraced cohort which had an improvement in the AI of only 1.1 degrees (95% confidence interval 0.6 to 1.6 degrees) (P<0.001).

CONCLUSIONS

In this comparative analysis of infants with residual acetabular dysplasia treated with abduction bracing or observation, part-time bracing significantly improved the acetabular index between 6 and 12 months of age. Part-time use of an abduction orthosis is effective for improving residual acetabular dysplasia in infants with DDH.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Predictive values for the severity of avascular necrosis from the initial evaluation in closed reduction of developmental dysplasia of the hip

The severity of avascular necrosis (AVN) after closed reduction of developmental dysplasia of the hip determines the final clinical outcomes. Our study aimed to correlate the possible predictors with the severity of AVN. After follow-up of the patients on skeletal maturity, 37 patients (39 hips) were included. Age at reduction is important to predict the severity of AVN. Older patients are at a greater risk of suffering from more severe AVN. Other values such as the degree of initial dislocation or the impact of the femoral head ossific nucleus show no precognition to the severity of AVN.

Results of medial open reduction of developmental dysplasia of the hip with regard to walking age

This study aimed to evaluate the outcome of medial open reduction for developmental dysplasia of the hip (DDH) in patients before and after walking age. A minimum 5-year radiographic and clinical follow-up compared 29 patients (group 1) before walking age with 38 patients (group 2) after walking age for DDH. The correction ratio of acetabular index was similar in both groups postoperatively (41.8% for group 1 and 44.9% for group 2), and it was statistically not significant (P>0.05). The Kalamchi-MacEwen classification showed no correlation between operative age and the rate of avascular necrosis (P>0.05). This report presents similar complication rates as that of the Severin criteria for medial open reduction of the hip and challenges the conventional belief that a medial open reduction for the treatment of DDH in a walking-age child at short-term to mid-term follow-up has comparable results.

Delayed diagnosis of developmental dislocation of the hip: the Western Australian experience

BACKGROUND

A delay in the diagnosis of developmental dislocation of the hip has many long-term consequences. This retrospective study was undertaken in order to establish an incidence of late-presenting developmental dislocation of the hip in Western Australia, and investigate possible causes for missed diagnoses.

METHOD

Data were collected retrospectively from 1 January to 31 December 2010. Theatre records were searched for operative descriptions including the words 'arthrogram hip', 'EUA hip', 'closed reduction hip', 'open reduction hip' and 'spica'. Medical records were checked to establish the demographic details and background history of cases identified. Delayed diagnosis of developmental dysplasia of the hip (DDH) was defined as a dislocated hip requiring operative reduction, diagnosed at age greater than 3 months.

RESULTS

Seventeen children with 21 dislocated hips were identified. Age at diagnosis ranged from 6 months to 5 years. Girls accounted for 88.2% (15/17) and the left hip was involved two-thirds of the time (14/21). Bilateral dislocations were found in four children.

CONCLUSION

This study has identified an incidence of late-presenting developmental hip dislocation of approximately three times the previously established rate. Possible reasons for this are explored. Additional retrospective audit is now underway, and changes are already in place to ensure that infants with DDH born in Western Australia are identified and treated as early as possible.

Modified triple innominate osteotomy for acetabular dysplasia: for better femoral head medialization and coverage

Steel's triple innominate osteotomy was created for correcting dysplastic acetabulum in adolescents and young adults. We modified Steel's triple innominate osteotomy with two anterior incisions and ramus cuts close to the acetabulum to improve the mobility of the fragment for better coverage of the hip. The purpose of this study was to compare these two techniques with respect to acetabular morphology, femoral head coverage, and medialization. From 1989 to 2007, 22 hips from 19 adolescents and young adults underwent triple innominate osteotomy for symptomatic acetabular dysplasia with Tonnis grades 1 or 2. We divided patients into group A (11 hips from 10 patients), comprising patients who underwent classical Steel's osteotomy, and group B (11 hips from nine patients), comprising patients who underwent modified Steel's osteotomy, with a minimum follow-up of 2 years. Preoperative and postoperative radiographs of pelvis in the standing position were available for comparison. We used Sharp's angle, center-edge angle, femoral head extrusion index, and center-head distance discrepancy to evaluate hip morphology, femoral head coverage, and medialization, respectively. The paired t-test was used for statistical calculation with P-value less than 0.05 considered significant. The postoperative Sharp's angle, center-edge angle, femoral head extrusion index, and center-head distance discrepancy all had better results in group B with statistical significance. Other variants such as age, sex, and operation side did not have any significance. No postoperative complication was encountered. Our modified technique provided a better mobility of the rotated fragment in correcting acetabular dysplasia with a short learning curve. Most importantly, we provided greater coverage and medialization of the femoral head for better long-term results.

LEVEL OF EVIDENCE

level III, retrospective comparative study.

MR-based parameters as a supplement to radiographs in managing developmental hip dysplasia

BACKGROUND

Some dysplastic hips with favorable radiographic parameters fail to develop normally, suggesting that we should consider cartilaginous or soft tissue structures for further information regarding the condition of the hip. The purpose of this study was to provide a clear definition of concentric reduction in developmental dysplasia of the hip (DDH) based on magnetic resonance imaging (MRI), and to determine how radiographic and MR-based parameters could be used together to treat dysplastic hips.

METHODS

We studied range of motion (ROM)-MRI of 25 patients with unilateral hip dysplasia (mean age at the time of MR imaging, 44.1 months). Each ROM-MRI consisted of a set of bilateral hip scans in the following positions: neutral; abduction; abduction- internal rotation; abduction-internal rotation-flexion; and adduction. Before MR scanning, the 25 patients received the following primary treatments: closed reduction (n = 15; at a mean age of 14.5 months); and open reduction (n = 10; at a mean age of 10.0 months). The following new parameters appear to be useful in treating DDH: 1) the labral angle, the angle the labrum makes with the acetabulum; 2) the uncorrected labral deformity (ULD), the "residual deformity" (deflection of the labrum) when the affected labrum is freed from pressure in abduction; and 3) the zone of compressive force (ZCF), the region of the acetabulum through which the body weight acts on the femoral head.

RESULTS

A concentrically-reduced hip is one in which the labrum points downward in the neutral position, at the same angle as that of the normal side; and in which the ZCF is zone 3, the inner acetabular zone as defined herein. The ULD and the ZCF may be determined precisely as we have done, or the physician may simply observe the changes in the orientation of the labrum and compare the changes qualitatively to the unaffected side, and likewise for the medial joint space.

CONCLUSIONS

Detailed analysis of the labrum as permitted by ROM-MRI, together with acetabular index and other parameters measured from radiographs, provides important information for physicians treating childhood hip dysplasia.

Developmental dysplasia of the hip - angle trends after operation in different age groups

INTRODUCTION

The aim of our study was to evaluate changes in collodiaphyseal, Hilgenreiner and Wiberg's centre-edge angle values in different age groups of children before and after surgical correction of developmental dysplasia of the hip.

MATERIAL AND METHODS

We evaluated 78 children with developmental hip dysplasia treated at University Children's Hospital in Belgrade during a 10-year period. Three age groups were analysed: the first group younger than 24 months of life, the second group between 25 and 48 months, and the third group older than 48 months of life. Three angles were evaluated separately before and after surgical correction: collodiaphyseal angle, Hilgenreiner angle and Wiberg's centre-edge angle.

RESULTS

We found a highly statistically significant difference (p < 0.001) before and after the operation for collodiaphyseal and Hilgenreiner angle in the first and second age group, while there was a statistically significant difference (p < 0.05) in the third age group. Regarding Wiberg's centre-edge angle, there was a highly statistically significant difference (p < 0.001) in all age groups. One way ANOVA revealed a highly statistically significant difference (p < 0.001) for collodiaphyseal and Hilgenreiner angle in age groups before the operation, while after surgery such a trend remained for Hilgenreiner angle. Regarding collodiaphyseal and Wiberg's centre-edge angle in the period after correction, there was no statistical difference (p > 0.05) between age groups of the participants.

CONCLUSIONS

Our findings demonstrate that age of participants is in correlation with correction of values for collodiaphyseal angle, Hilgenreiner angle and Wiberg's centre-edge angle in surgically treated children diagnosed with developmental dysplasia of the hip.

New treatment method for developmental dysplasia of the hips after walking age: arthroscopic reduction with limboplasty based on the findings of preoperative imaging

BACKGROUND

What makes treatment choice for developmental dysplasia of the hips diagnosed after walking age difficult is the poor understanding of prereduction conditions that obstruct the reduction in spatial terms. To evaluate these problems, we employed subtraction three-dimensional imaging to search for the factors involved in intraarticular obstruction. On the basis of the findings of preoperative subtraction threedimensional imaging from computed tomography, we developed a new method, a minimum invasive arthroscopic reduction with limboplasty, for reduction of developmental dysplasia of the hips after walking age. The purposes of this report were to: (1) describe the technique of the arthroscopic procedure, and (2) evaluate our new method using radiographic parameters.

METHODS

Ten patients with ten hips with developmental dysplasia after walking age treated by arthroscopic reduction with limboplasty were included in this study. The mean age of the patients at reduction was 22.6 months (range, 18.6-29.7 months); mean age at follow up was 7.2 years (range, 3.9-10.9 years); and mean follow up was 5.4 years (range, 1.7-9.0 years). These ten hips were evaluated using radiographic measurements.

RESULTS

Moderate or severe avascular necrosis of the femoral head was not observed. Two hips that had a spherical-shaped head with minimal residual height loss or coxa magna were classified as Kalamchi and MacEwen grade 1. Additional surgery had been performed for two hips classified as Severin group 4 during the course of follow up. These two hips were classified as Severin group 1 at final examination. One more hip was classified as Severin group 4 at final examination, and additional surgery was recommended. The remaining seven hips (70%) therefore obtained good evaluations by arthroscopic reduction with limboplasty alone.

CONCLUSIONS

We developed a new reduction method by using an arthroscopic procedure for the reduction of developmental dysplasia of the hips after walking age when this dysplasia failed to be reduced with nonoperative methods. The result of our new method is acceptable because good evaluations were obtained in 70% of hips 5.4 years after reduction by our new method alone.

To screen or not to screen? A decision analysis of the utility of screening for developmental dysplasia of the hip

BACKGROUND

The United States Preventive Services Task Force recently determined that they could not recommend any screening strategies for developmental dysplasia of the hip. Disparate findings in the literature and treatment-related problems have led to confusion about whether or not to screen for this disorder. The purpose of the present study was to determine, with use of expected-value decision analysis, which of the following three strategies leads to the best chance of having a non-arthritic hip by the age of sixty years: (1) no screening for developmental dysplasia of the hip, (2) universal screening of newborns with both physical examination and ultrasonography, or (3) universal screening with physical examination but only selective use of ultrasonography for neonates considered to be at high risk.

METHODS

Developmental dysplasia of the hip, avascular necrosis, and the treatment algorithm were carefully defined. The outcome was determined as the probability of any neonate having a non-arthritic hip through the age of sixty years. A decision tree was then built with decision nodes as described above, and chance node probabilities were determined from a thorough review of the literature. Foldback analysis and sensitivity analyses were performed.

RESULTS

The expected value of a favorable hip outcome was 0.9590 for the strategy of screening all neonates with physical examination and selective use of ultrasonography, 0.9586 for screening all neonates with physical examination and ultrasonography, and 0.9578 for no screening. A lower expected value implies a greater risk for the development of osteoarthritis as a result of developmental dysplasia of the hip or avascular necrosis; thus, the optimum strategy was selective screening. This model was robust to sensitivity analysis, except when the rate of missed dysplasia rose as high as 4/1000 or the rate of treated hip subluxation/dislocation was the same; then, the optimum strategy was to screen all neonates with both physical examination and ultrasonography.

CONCLUSIONS

Our decision analytic model indicated that the optimum strategy, associated with the highest probability of having a non-arthritic hip at the age of sixty years, was to screen all neonates for hip dysplasia with a physical examination and to use ultrasonography selectively for infants who are at high risk. Additional data on the costs and cost-effectiveness of these screening policies are needed to guide policy recommendations.

Single-stage open reduction, Salter innominate osteotomy, and proximal femoral osteotomy for the management of developmental dysplasia of the hip in children between the ages of 2 and 4 years

The management of neglected developmental dysplasia of the hip in walking children has always been a challenge to orthopedic surgeons. The aim of this study was to access the early clinical and radiographic results of surgical treatment of such cases using one-stage open reduction, Salter innominate osteotomy, and proximal femoral osteotomy. Seventy-one surgeries were performed in 55 patients. Favorable clinical and radiographic outcomes were comparable to other studies. We concluded that this single-stage surgery is a technically demanding, but satisfactory procedure in the management of neglected developmental dysplasia of the hip patients, and when performed adequately in indicated patients in specialized centers, it is expected to give good short-term results.

Acetabular cartilaginous angle: a new method for predicting acetabular development in developmental dysplasia of the hip in children between 2 and 18 months of age

BACKGROUND

A new method of arthrographic measurement, the acetabular cartilaginous angle (ACA), is described here in an effort to find a simple, reliable, and reproducible measurement that can predict future acetabular development after successful closed reduction of developmental dysplasia of the hip (DDH).

METHODS

A prospective study was conducted for children with DDH who were treated successfully by closed reduction in the authors' institute from 1994 through 2000. The total number of patients who completed the follow-up in our study until full acetabular development or acetabuloplasty was 162, with 234 affected hips. Their age at the time of closed reduction ranged between 2 and 18 months (mean, 7.48 months; SD +/-5.162). There were 135 girls and 27 boys. Frank dislocation of the hip was present in 195 hips, whereas acetabular dysplasia with or without lateralization of the femoral head was seen in 39 hips. The average follow-up was 9.2 years (range, 6-11 years).

RESULTS

Multivariate analysis of 6 variables showed that the mean age and acetabular index at the time of closed reduction were significant to predict later acetabuloplasty, whereas ACA was highly significant. These 3 significant variables together had 96.58% correct prediction. The authors observed that some hips with high acetabular index developed satisfactorily, and other hips with small values required later acetabuloplasties. On the other hand, there was a clear cut value of ACA (20 degrees) under which almost all hips (99.5%) developed satisfactorily and another clear cut value of ACA (24 degrees) above which all hips (100%) needed acetabuloplasty.

CONCLUSIONS

Acetabular cartilaginous angle is considered a reliable measurement to identify hips with DDH that will need later acetabuloplasty after successful closed reduction. The acetabular index is important in monitoring acetabular development, and reaching a value of less than 30 degrees 2 years after closed reduction is considered a good sign of acetabular development.

Treatment for developmental dysplasia of the hip using the Pavlik harness

We reviewed the medical records of 115 patients with 130 hips with developmental dysplasia with complete dislocation in the absence of a neuromuscular disorder, spontaneous reduction with a Pavlik harness, and a minimum of 14 years’ follow-up. The mean age at the time of harness application was 4.8 months (1 to 12) and the mean time spent in the harness was 6.1 months (3 to 12). A total of 108 hips (83.1%) were treated with the harness alone and supplementary surgery for residual acetabular dysplasia, as defined by an acetabular index > 30°, was performed in 22 hips (16.9%).

An overall satisfactory outcome (Severin grade I or II) was achieved in 119 hips (91.5%) at a mean follow-up of 16 years (14 to 32) with a follow-up rate of 75%. Avascular necrosis of the femoral head was noted in 16 hips (12.3%), seven of which (44%) underwent supplementary surgery and nine (56%) of which were classified as satisfactory. The acetabular index was the most reliable predictor of residual acetabular dysplasia.

Prediction of acetabular development after closed reduction by overhead traction in developmental dysplasia of the hip

BACKGROUND

The prediction of acetabular development after reduction of developmental dysplasia of the hip (DDH) is important to ensure optimal timing of acetabuloplasty and to avoid unnecessary surgery. The objective of this study was to find early and reliable predictors of future acetabular dysplasia in the hips reduced by overhead traction (OHT).

METHODS

We retrospectively reviewed 45 hips in 40 patients treated by OHT for DDH without additional procedures. The average age at the time of closed reduction was 9.3 months, and the average age at the latest examination was 17.3 years. Residual hip dysplasia at skeletal maturity was defined according to Severin's classification. The following variables were evaluated as possible predictors of the final outcome: age at reduction, severity of the dislocation, serial measurements of acetabular index (AI), center-edge angle of Wiberg (CE), and the center-head discrepancy distance (CHDD).

RESULTS

Sixty-two percent of the hips had satisfactory results in Severin I/II and 38% had unsatisfactory results in Severin III. Bilateral DDH showed significantly poorer outcome than unilateral DDH. The average AI of the unsatisfactory group was significantly greater than that of the satisfactory group at 4 years or more after reduction. Similarly, the average CE of the satisfactory group was greater than that of the unsatisfactory group at 5 years or more after reduction. In unilateral cases, the AI and the CE of the uninvolved hip at 1 year after reduction also correlated with the final outcome of the involved hip.

CONCLUSIONS

The AI of 4 years and the CE of 5 years after reduction were the earliest predictors of the final outcome. Careful consideration for the need of acetabuloplasty would be given at 4 or 5 years after reduction by OHT. Bilateral DDH and poor acetabular coverage of the uninvolved hip in unilateral DDH were the prognostic factors of unfavorable acetabular development of the dislocated hip.