International Hip Dysplasia Institute Research Articles

Outcomes of open reduction for hip dislocations in children with connective tissue disorders*

Purpose: While children with hypermobility and/or ligamentous laxity due to coexisting connective tissue disorders might be expected to have worse outcomes after open reduction for hip dislocations, there is minimal prior research on this topic. Methods: All open reduction surgeries for hip dislocations performed at a single urban, tertiary-care children’s hospital from 2009 to 2023 were reviewed retrospectively. Those with connective tissue disorders secondary to a diagnosed syndrome or genetic disorder were included. Patients with <1 year of follow-up or hip instability in the setting of Trisomy 21 were excluded. Clinical and radiographic data was collected. Instances of re-dislocation, proximal femoral growth disturbance, residual acetabular dysplasia, and arthrofibrosis were recorded. Results: Twenty-three hips (15 patients) were included. Mean age at the time of surgery was 19.6 months (Range: 8.2–36.0 months), and mean follow-up was 4.3 years. The most common connective tissue disorder condition included was Ehlers-Danlos syndrome (13%). A majority of open reductions were performed via an anterior approach (96%). Seven hips (30%) underwent a concomitant pelvic osteotomy without femoral osteotomy and seven hips (30%) underwent both pelvic and femoral osteotomies. Twenty-two hips (96%) were International Hip Dysplasia Institute grade 1 at the final follow-up. Re-dislocation occurred in four hips (17%); eight hips (35%) demonstrated residual acetabular dysplasia, five hips (22%) demonstrated proximal femoral growth disturbance, and nine hips (39%) developed stiffness postoperatively. Conclusions: Patients with connective tissue disorders and ligamentous laxity have comparable rates of residual acetabular dysplasia, proximal femoral growth disturbance, and (surprisingly) stiffness as typical developmental dysplasia of the hip following open hip reduction surgery. Although the re-dislocation rate in the connective tissue disorders group was approximately 2–3 times higher, the difference did not reach statistical significance. Given that the study was limited by a low sample size, however, it is possible that the findings of no difference in residual acetabular dysplasia and proximal femoral growth disturbance were potentially due to a lack of power. Level of evidence: IV.

Association between ossific nucleus volume changes and postoperative avascular necrosis risk in children with developmental dysplasia of the hip

This study aimed to investigate the correlation between ossific nucleus volume and avascular necrosis (AVN) in pediatric patients diagnosed with developmental dysplasia of the hip (DDH). Analyzing 211 cases, including 119 open reduction (OR) and 92 closed reduction (CR) procedures, we quantified ossific nucleus volume using magnetic resonance imaging (MRI). Categorizing the OR group based on ossific nucleus volume revealed no statistically significant difference in AVN incidence. Similarly, in the CR cohort, there was no significant discrepancy in AVN occurrence between subgroups with or without the ossific nucleus. Logistic regression in CR identified the international hip dysplasia institute (IHDI) grade as a significant AVN risk factor (p = 0.007). IHDI grades 3 and 4 exhibited a 6.94 times higher likelihood of AVN compared to grades 1 and 2. Across CR and OR, neither initial age nor ossific nucleus volume emerged as AVN risk factors. In conclusion, ossific nucleus volume does not pose a risk for AVN in DDH children undergoing CR or OR, emphasizing the clinical significance of IHDI grading in predicting AVN risk during CR and the importance of early intervention to prevent treatment delays.

Risk factors for avascular necrosis of the femoral head after developmental hip dislocation reduction surgery and construction of Nomogram prediction model

BackgroundTo analyze the risk factors for the development of avascular necrosis (AVN) of the femoral head after reduction surgery in children with developmental hip dysplasia (DDH), and to establish a prediction nomogram.MethodsThe clinical data of 134 children with DDH (169 hips) treated with closure reduction or open reduction from December 2016 to December 2019 were retrospectively analyzed. Independent risk factors for AVN after DDH reduction being combined with cast external immobilization were determined by univariate analysis and multivariate logistic regression and used to generate nomograms predicting the occurrence of AVN.ResultsA total of 169 hip joints in 134 children met the inclusion criteria, with a mean age at surgery of 10.7 ± 4.56 months (range: 4–22 months) and a mean follow-up duration of 38.32 ± 27.00 months (range: 12–94 months). AVN developed in 42 hip joints (24.9%); univariate analysis showed that the International Hip Dysplasia Institute (IHDI) grade, preoperative development of the femoral head ossification nucleus, cartilage acetabular index, femoral head to acetabular Y-shaped cartilage distance, residual acetabular dysplasia, acetabular abduction angle exceeding 60°, and the final follow-up acetabular index (AI) were associated with the development of AVN (P < 0.05). Multivariate logistic regression analysis showed that the preoperative IHDI grade, development of the femoral head ossification nucleus, acetabular abduction angle exceeding 60°, and the final follow-up AI were independent risk factors for AVN development (P < 0.05). Internal validation of the Nomogram prediction model showed a consistency index of 0.833.ConclusionPreoperative IHDI grade, preoperative development of the femoral head ossification nucleus, final AI, and acetabular abduction angle exceeding 60° are risk factors for AVN development. This study successfully constructed a Nomogram prediction model for AVN after casting surgery for DDH that can predict the occurrence of AVN after casting surgery for DDH.

External Fixator Stabilization Following Open Reduction and Combined Pelvic and Proximal Femur Osteotomy in Developmental Dysplasia Hip: A Surgical Note

Introduction: Maintenance of hip joint reduction after combined pelvic and femoral osteotomy in developmental dysplasia of the hip (DDH) in children using a hip-spica cast has the potential to cause numerous cast-related complications. We proposed a modification of the surgical technique where the hip reduction is maintained with an external fixator to avoid cast-related complications. Methodology: The surgical technique involved the placement of Scahnz pins along the iliac crest or lateral aspects of the ilium, in the supra-acetabular region below the pelvic osteotomy site, and the proximal femur. The pins were connected and stabilized with tubular/solid rods. Six children with 10 dysplastic hips [4 bilateral and 2 unilateral, International Hip Dysplasia Institute (IDHI) grade IV] were operated on with pelvic and femoral osteotomies and external fixator construct. The fixators were removed after 8 weeks and the children were followed up at 3, 6, 12, and 18 months. Results: The average age of the children was 6.5 years (range: 4 to 11 y). After an average follow-up of 10 months, the hips were reduced with IDHI grade of I in 7 hips and IDHI grade of II in 3 hips. There were no wound complications. Superficial pin tract infections were seen in all patients but responded to topical antibiotic application. There was no unplanned visit by the parents and no one complained of perineal hygiene issues. Conclusion: The external fixator construct maintains the hip reduction in DDH and allows the osteotomy sites to heal without any wound-related complications.

The efficacy of gradual reduction using two-stage traction for developmental dysplasia of the hip in southern China.

This study aimed to report the preliminary outcome of gradual reduction (GR) utilizing two-stage traction (TST) compared with traditional traction (TT) in the treatment of developmental dysplasia of the hip (DDH) and to evaluate whether the prognosis of the TST is better than that of TT. The following information on children diagnosed with DDH who underwent treatment with GR using two-stage traction or traditional traction between June 2016 and August 2017 was collected: sex, age, weight, acetabular index (AI), International Hip Dysplasia Institute (IHDI) classification, femoral head ossification, traction time, reduction quality, and labrum shape in arthrography. The AI, IHDI classification, second operation rate, and incidence of femoral head avascular necrosis (AVN) were analyzed after the final comprehensive 1-year follow-up. In this study, 27 cases (31 hips: 18 left and 13 right) were enrolled, with 18 hips (16 cases) assigned to the TT group and 13 hips (11 cases) assigned to the TST group, with the corresponding average age at diagnosis of 5.56 ± 1.66 and 4.06 ± 1 months (p < 0.001). For both TT and TST groups, the average age at operation was 6.01 ± 1.67 and 65 ± 0.86 months (p = 0.435), the distribution of affected left and right sides was 10/8 and 8/5 hips (p = 1), and the average initial AI was 37.11 ± 3.26 and 36.77 ± 4.34 (p = 0.804), respectively. IHDI classification III/IV was observed in 15/3 and 11/2 hips, respectively (p = 1). Femoral head ossification was present in 6/18 hips in the TT group and 2/13 hips in the TT group (p = 0.412). The total traction time was 13.22 ± 2.6 days for the TT group and 49.23 ± 25.77 days for the TST group (p < 0.001). After GR, IHDI classification III/IV was observed in 9/9 and 12/1 hips, respectively (p = 0.02). AVN was present in 5/18 hips in the TT group and 0/13 hips in the TST group (p = 0.048), while the need for a second operation was approved in 5/18 hips in the TT group and 1/13 hips in the TST group (p = 0.359) at the final follow-up. Two-stage traction can significantly decrease the ratios of IHDI classifications III and IV and the incidence of AVN compared to traditional traction; also, it significantly reduces the total traction time.

Hip arthrogram parameters predict radiographic outcomes of patients with developmental dysplasia of the hip treated by closed reduction.

This study aimed to investigate the relationship between intraoperative hip arthrogram parameters and residual acetabular dysplasia (RAD) and avascular necrosis of the femoral head (AVN) in children with developmental dysplasia of the hip (DDH) treated by closed reduction. We retrospectively analyzed the data of 102 patients (110 hips; mean age, 14.6 months ± 4.7 months) with DDH treated by closed reduction. A hip arthrogram was routinely performed during the operation. The femoral head coverage rate (FHC), medial pool distance of the hip (MPD), labral inversion, and reduction quality classification were evaluated under the hip arthrogram. The presence of RAD and AVN was assessed on radiographs at the last follow-up. The relationship between each arthrogram parameter and RAD as well as AVN was investigated using a t-test, chi-square test, and logistic regression. The overall FHC and medial pool distance of the hip (MDP) averaged 42.2% ± 12% and 8.1% ± 11.7%, respectively. There were 80 hips (72.7%) with labral inversion and 30 hips (27.2%) without. The reduction quality was type A in 57 hips (51.8%), type B in 28 hips (25.4%), and type C in 25 hips (22.7%). A total of 32 hips (29%) were in the RAD group, and 78 hips (71%) were in the recovered group according to whether pelvic osteotomy was performed or not and according to the last Severin grade. The FHC was significantly higher in the recovered group than that in the RAD group (P = 0.014). No significant difference was observed in sex, age at reduction, side, preoperative acetabular index, International Hip Dysplasia Institute classification, follow-up time, quality of reduction, MDP, and proportion of labral inversion between the recovered and RAD groups. Logistic regression analysis showed that only the FHC was a risk factor for RAD. The incidence of AVN above type II was 11.8% in this group of patients, and the incidence of AVN was significantly higher in patients with labral inversion (23.2%) than that in those without (7.5%; P = 0.041). Logistic regression analysis showed that labral inversion was a risk factor for AVN. The FHC measured under arthrogram can predict the occurrence of RAD after closed reduction of DDH, whereas MDP, reduction quality classification, and labral inversion are of little significance. Labral inversion is a risk factor for AVN.

Does brace treatment following closed reduction of developmental dysplasia of the hip improve acetabular coverage?

Abduction bracing is commonly used to treat developmental dysplasia of the hip (DDH) following closed reduction and spica casting, with little evidence to support or refute this practice. The purpose of this study was to determine the efficacy of abduction bracing after closed reduction in improving acetabular index (AI) and reducing secondary surgery for residual hip dysplasia. We performed a retrospective review of patients treated with closed reduction for DDH at a single tertiary referral centre. Demographic data were obtained including severity of dislocation based on the International Hip Dysplasia Institute (IHDI) classification, age at reduction, and casting duration. Patients were prescribed no abduction bracing, part-time, or full-time wear post-reduction and casting. AI measurements were obtained immediately upon cast removal and from two- and four-year follow-up radiographs. A total of 243 hips underwent closed reduction and 82% (199/243) were treated with abduction bracing. There was no difference between those treated with or without bracing with regard to sex, age at reduction, severity of dislocation, spica duration, or immediate post-casting AI (all p > 0.05). There was no difference in hips treated with or without abduction brace with regard to AI at two years post-reduction (32.4° (SD 5.3°) vs 30.9° (SD 4.6°), respectively; p = 0.099) or at four years post-reduction (26.4° (SD 5.2°) vs 25.4° (SD 5.1°), respectively; p = 0.231). Multivariate analysis revealed only IHDI grade predicted AI at two years post-reduction (p = 0.004). There was no difference in overall rate of secondary surgery for residual dysplasia between hips treated with or without bracing (32% vs 39%, respectively; p = 0.372). However, there was an increased risk of early secondary surgery (< two years post-reduction) in the non-braced group (11.4% vs 2.5%; p = 0.019). Abduction bracing following closed reduction for DDH treatment is not associated with decreased residual dysplasia at two or four years post-reduction but may reduce rates of early secondary surgery. A prospective study is indicated to provide more definitive recommendations.

The Optimal Age for Surgical Management of DDH Differs by Treatment Method.

There is a lack of consensus on the optimal age for specific surgical interventions for developmental dysplasia of the hip. We compared radiographic and clinical outcomes among patients who were treated with closed reduction (CR), open reduction (OR), and open reduction with concomitant pelvic osteotomy (ORP) for the treatment of a dislocated hip. We sought to identify the optimal age at treatment within each of these groups. We retrospectively reviewed 256 hips (n=195 patients) who underwent CR (n=96), OR (n=116), or an ORP (n=44) as their index procedure at a single institution between January 1, 2004 and September 23, 2020. Radiographic outcomes included acetabular index, The International Hip Dysplasia Institute classification, and acetabular depth ratio. The incidence of further corrective surgery (FCS), defined as the need for an additional femoral and/or pelvic osteotomy before skeletal maturity, and the optimal age cutoffs for index surgery within each surgical group were determined. After adjusting for age and sex, the incidence of FCS was 13.8% in the CR group, 29.2% in the OR group, and 9.2% in the ORP group. Earlier surgery was protective against FCS in the CR and OR groups. In contrast, patients in the ORP group who were older at index procedure were less likely to undergo FCS. Optimal age at surgery was 9.9 months (CR), 11.5 months (OR), and 21.4 months (ORP). Compared with older patients, younger patients were associated with a larger average decrease in the acetabular index and a larger average increase in acetabular width during the first 5 years post surgery. Age at index surgical procedure was correlated with both clinical and radiographic outcomes. Age at index procedure did impact the risk of subsequent FCS, particularly in the CR and ORP groups. Based on our analysis, CR should be considered before 9.9 months of age and OR considered before 11.5 months of age to minimize the risk of FCS during childhood. This work highlights the importance of considering age-related heterogeneity in developmental dysplasia of the hip treatment outcomes. Level III-retrospective comparative study.

Abduction Bracing Following Anterior Open Reduction for Developmental Dysplasia of the Hip Does Not Improve Residual Dysplasia or Reduce Secondary Surgery.

Abduction bracing is commonly used following open reduction and spica casting of developmental dysplasia of the hip. However, there is little evidence to support or refute this practice that carries associated cost and burden for families. The purpose of this study was to determine the efficacy of abduction bracing after open reduction in improving the acetabular dysplasia and reducing the rate of secondary surgery for residual dysplasia. This is a retrospective study of patients treated with open reduction at a single tertiary referral center. Demographic data, severity of dislocation [International Hip Dysplasia Institute (IHDI) class], age at reduction, and casting duration were obtained. Patients were prescribed no bracing, part-time (≤18h/d), or full-time (≥20h/d) brace wear based on surgeon preference. Acetabular index (AI) measurements were obtained at cast removal and at 2- and 4-year follow-up. A total of 146 hips underwent open reduction with 61% (89/146) of hips treated with abduction bracing. There was no difference between braced and nonbraced cohorts with regards to sex, age at time of reduction, dislocation severity, cast duration, immediate postcasting AI, or incidence of medial open reduction. There was no difference in hips treated with or without brace following open reduction with regards to AI at 2 years postreduction (31.8±6.7 vs. 30.4±6.1 degrees, P =0.27) or at 4 years postreduction (24.9±6.5 vs. 24.7±6.5 degrees, P =0.97). However, further analysis showed lower mean AI at 2-year follow-up for braced versus nonbraced patients following medial open reduction (30.0±5.7 vs. 34.5±7.0 degrees, P =0.02). This difference was no longer present at 4-year follow-up (26.6±6.8 vs. 24.2±6.6 degrees, P =0.44). However, 4/19 (21%) nonbraced hips underwent secondary surgery for residual dysplasia and were consequently excluded from the AI measurement at 4 years postreduction (compared with 4/39 [10%] braced hips within the same time period). There was no difference in the rate of secondary surgery between braced and nonbraced hips (30% vs. 33%, respectively, P =0.70). Multivariate analysis demonstrated that neither IHDI classification, bracing, nor age at reduction predicted residual dysplasia. Abduction bracing following anterior open reduction for developmental dysplasia of the hip is not associated with decreased residual dysplasia at 2/4 years postreduction or with decreased secondary surgery. These results suggest that abduction bracing following anterior open reduction may not provide clinical benefit. However, abduction bracing may be beneficial following medial open reduction. A prospective study is necessary to provide more definitive recommendations. Level III-therapeutic study.

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

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

A comprehensive nonoperative treatment protocol for developmental dysplasia of the hip in infants.

Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years.

Tönnis and the Novel IHDI Radiographic Classification Systems for the Developmental Dysplasia of The Hip (DDH): Evaluation of 406 hips with DDH

In this study, we aimed to compare the efficiency of Tönnis and the novel International Hip Dysplasia Institute (IHDI) in decision making and in presuming the outcomes in children who had undergone closed reduction and casting. 406 hips of 298 patients who had undergone closed reduction and spica casting were included in this retrospective study. All hips were classified according to Tönnis and IHDI systems. Bucholz-Ogden classification was used for avascular necrosis. The outcomes of patients for each classification system were compared, in terms of the presence of avascular necrosis, redislocations and secondary surgeries at the end of the follow-up period. 318 hips were evaluated as Tönnis grade 2 dysplasia. 24 had avascular necrosis, 9 had redislocations. 79 hips were evaluated as Tönnis grade 3 dysplasia. 18 had AVN, 7 had redislocations. 9 hips were evaluated as Tönnis grade 4 dysplasia 3 had AVN, 4 had redislocations. 203 patients were evaluated as IHDI grade 2 dysplasia. 7 had AVN, 7 had redislocations.185 patients were assessed as IHDI grade 3 dysplasia. 33 had AVN, 11 had redislocations. 18 patients were evaluated as IHDI grade 4 dysplasia. 5 had AVN, 6 had redislocations. Both Tönnis classification and IHDI classification systems are reliable and efficient systems for evaluating the severity and predicting the success of closed reduction and casting for the treatment of DDH. IHDI classification has certain benefits, such as being a practical classification and a better distribution within the groups.

Risk factors for postoperative avascular necrosis of the femoral head in children with developmental dysplasia of the hip.

To investigate factors associated with postoperative avascular necrosis of the femoral head (ANFH) in developmental dysplasia of the hip (DDH) patients, and if or how the associations varied among different subpopulations of age, sex and surgical method. Patients with DDH were enrolled between October 31, 2016 and July 15, 2020 in this retrospective cohort study. The average follow-up time was 21.42 ± 10.02 months. The outcome was postoperative ANFH. The main study variables were the DDH classification, Tonnis grade, International Hip Dysplasia Institute (IHDI) classification, and preoperative traction. Multivariate logistic regression was employed to assess the associations between main study variables and postoperative ANFH. Subgroup analysis was carried out based on age at reduction, sex and surgical method. Odds ratio (ORs) and 95% confidence intervals (CIs) were calculated. A total of 427 children with DDH were included, with 92 (21.55%) in the ANFH group, and 335 (78.45%) in the non-ANFH group. DDH classification was positively correlated with the risk of postoperative ANFH (OR = 4.14, 95% CI, 1.08-15.77, P = 0.038). Children with preoperative traction had a significantly decreased risk of postoperative ANFH in contrast to those without preoperative traction (OR = 0.37, 95% CI, 0.22-0.61, P < 0.001). Children aged 1-3 years who received preoperative traction has a significantly reduced risk of postoperative ANFH than those who did not receive preoperative traction (OR = 0.28, 95% CI, 0.15-0.51, P < 0.001). For children aged >3 years, positive association was found between DDH classification and the risk of postoperative ANFH (OR = 3.75, 95% CI, 1.51-9.31, P = 0.004). Girls with a more severe DDH type had a significantly higher risk of postoperative ANFH (OR = 3.80, 95% CI, 1.80-8.02, P < 0.001). Receiving preoperative traction was associated with a significantly decreased risk of postoperative ANFH in girls (OR = 0.37, 95% CI, 0.22-0.61, P < 0.001). For children undergoing open reduction, DDH classification was positively associated with the risk of postoperative ANFH (OR = 3.01, 95% CI, 1.65-5.50, P < 0.001), and those with preoperative traction had a lower risk of postoperative ANFH compared with those without preoperative traction (OR = 0.35, 95% CI, 0.20-0.61, P < 0.001). DDH classification and preoperative traction were associated with the risk of postoperative ANFH, and these associations varied across DDH patients with different ages, sexes and surgical methods.

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

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

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

BackgroundDevelopmental 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).MethodsA 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.ResultsThere 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).ConclusionsThese 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.

Testing of an Ultrasound-Limited Imaging Protocol for Pavlik harness Supervision (TULIPPS) in developmental dysplasia of the hip: a randomized controlled trial.

There is no consensus regarding optimum timing and frequency of ultrasound (US) for monitoring response to Pavlik harness (PH) treatment in developmental dysplasia of the hip (DDH). The purpose of our study was to determine if a limited-frequency hip US assessment had an adverse effect on treatment outcomes compared to traditional comprehensive US monitoring. This study was a single-centre noninferiority randomized controlled trial. Infants aged under six months whose hips were reduced and centred in the harness at initiation of treatment (stable dysplastic or subluxable), or initially decentred (subluxated or dislocated) but reduced and centred within four weeks of PH treatment, were randomized to our current standard US monitoring protocol (every clinic visit) or to a limited-frequency US protocol (US only at end of treatment). Groups were compared based on α angle and femoral head coverage at the end of PH treatment, acetabular indices, and International Hip Dysplasia Institute (IHDI) grade on one-year follow-up radiographs. Overall, 100 patients were included; 42 patients completed the standard protocol (SP) and 40 completed the limited protocol (LP). There was no significant difference in mean right α angle at the end of treatment (SP 70.0° (SD 3.2°) ; LP 68.7° (SD 2.9°); p = 0.033), nor on the left (SP 69.0° (SD 3.5°); LP 68.1° (SD 3.3°); p = 0.128). There was no significant difference in mean right acetabular index at follow-up (SP 23.1° (SD 4.3°); LP 22.0° (SD 4.1°); p = 0.129), nor on the left (SP 23.3° (SD 4.2°); LP 22.8° (SD 3.9°); p = 0.284). All hips had femoral head coverage of > 50% at end of treatment, and all were IHDI grade 1 at follow-up. In addition, the LP group underwent a 60% reduction in US use once stable. Our study supports reducing the frequency of US assessment during PH treatment of DDH once a hip is reduced and centred.Cite this article: Bone Joint J2022;104-B(9):1081-1088.

1034 Radiological Outcomes Following Surgery for Developmental Dysplasia of the Hip

Abstract Aim Developmental dysplasia of the hip (DDH) is a condition affecting newborns, in which abnormal acetabulum development can result in femoral head subluxation or dislocation. This study aims to retrospectively evaluate radiological outcomes of patients with DDH, treated by either closed reduction, open reduction, or open reduction with osteotomy. Method This study included 59 hips of 54 patients with a median age of 19.6 months at the time of surgery. Radiographs were assessed for the International Hip Dysplasia Institute (IHDI) grade of dislocation, acetabular index (AI), centre-edge angle (CEA), Severin classification and avascular necrosis (AVN). Results Median duration of follow up between primary operation and latest available radiograph was 4.9 years. Pre-operatively, 41 hips were IHDI Grade IV, 16 hips were Grade III and two hips were Grade II. Mean pre-operative AI was 37.9°, which decreased to 22.7° at the latest follow up. Mean CEA was 22.9°. 25 hips were found to be Severin class I, eight hips were class II and three hips were class III. Four hips developed Group II AVN and one hip developed Group III. Nine hips required further surgery. Conclusions The study found overall favourable radiological outcomes of treatment of DDH, with minimal differences between each operation. Longer follow up is needed to evaluate time-dependent outcomes such as Severin class and AVN. A patient-reported outcome questionnaire is necessary to provide information on the correlation of radiological outcomes and physical function.

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

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

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

We aimed to compare the outcomes between closed reduction (CR) and open reduction (OR) in children aged 6-24months with developmental dysplasia of the hip (DDH) who could be reduced safely and stably by the closed reduction operation. 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. 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. In children aged 6-24months with DDH, if a stable and safe CR can be obtained but with medial joint space up to 6mm, CR should be attempted first.

The International Hip Dysplasia Institute (IHDI) classification is more informative than the Tönnis classification.

A new, supposedly more reproducible radiographic classification, set to replace the Tönnis classification of hip dislocations, was proposed in 2015: the International Hip Dysplasia Institute (IHDI) classification. To compare the IHDI classification with the Tönnis classification when evaluating the severity of hip dislocations as well as their respective inter- and intra-observer reliability. Since January 2000, Swedish-born children with a hip dislocation were prospectively registered. From this registry, radiographs of 97 hips in 79 patients (91% girls; median age = 7 months), born in 2000-2009, were analyzed. Two observers, one consultant and one resident, classified each hip both by IHDI and Tönnis twice. The IHDI classification had a more even distribution of grades with the majority in grade 2-3. The Tönnis classification graded the majority (77%) of the patients as grade 2 and equally among the other grades. There was moderate inter-observer agreement using both methods calculated with Kappa, 0.61 (95% confidence interval [CI] = 0.44-0.79) for Tönnis and 0.62 (95% CI = 0.49-0.74) for IHDI. The resident calculated Tönnis with weak intra-observer reliability of 0.57 (95% CI = 0.40-0.74) compared to high intra-observer reliability of 0.86 (95% CI = 0.74-0.98) for the consultant. Both observers graded IHDI with high intra-observer reliability. IHDI is more discriminative than the Tönnis classification when evaluating the severity of a hip dislocation in infants.