Growth Stimulating Minimal Acetabuloplasty, Alongside Hip Open Reduction: A Simpler One-stop Operative Treatment for Developmental Dysplasia of the Hip.

Although there are several predominantly single-center case series in the literature, relatively little prospectively collected data exist regarding the outcomes of open hip reduction (OR) for infantile developmental dysplasia of the hip (DDH). The purpose of this prospective, multi-center study was to determine the outcomes after OR in a diverse patient population. The prospectively collected database of an international multicenter study group was queried for all patients treated with OR for DDH. Minimum follow-up was 1 year. Proximal femoral growth disturbance (PFGD) was defined by consensus review using Salter's criteria. Persistent acetabular dysplasia was defined as an acetabular index >90th percentile for age. Statistical analyses were performed to compare preoperative and operative characteristics that predicted re-dislocation, PFGD, and residual acetabular dysplasia. A cohort of 232 hips (195 patients) was identified; median age at OR was 19 months (interquartile range 13 to 28) and median follow-up length was 21 months (interquartile range 16 to 32). Re-dislocation occurred in 7% of hips (n=16/228). The majority (81%; n=13/16) occurred in the first year after initial OR. Excluding patients with repeat dislocation, 94.5% of hips were IHDI 1 at most recent follow-up. On the basis of strict radiographic review, some degree of PFGD was present in 44% of hips (n=101/230) at most recent follow-up. Seventy-eight hips (55%) demonstrated residual dysplasia compared with established normative data. Hips that had a pelvic osteotomy at index surgery had about half the rate of residual dysplasia (39%; n=32/82) versus those without a pelvic osteotomy with at least 2 years follow-up (78%; n=46/59). In the largest prospective, multicenter study to date, OR for infantile DDH was associated with a 7% risk of re-dislocation, 44% risk of PFGD, and 55% risk of residual acetabular dysplasia at short term follow-up. The incidence of these adverse outcomes is higher than previous reports. Patients treated with concomitant pelvic osteotomy had lower rates of residual dysplasia. These prospectively collected, multicenter data provide better generalizable information to improve family education and appropriately set expectations. Level II, prospective comparative study.

Avascular necrosis (AVN) and residual acetabular dysplasia are the two main complications of developmental dysplasia of the hip (DDH) treatment. Although early reduction of the hip may decrease the incidence of residual dysplasia, it may increase the incidence of AVN and vice versa. However, we do not know if changes in surgical technique may lead to a modification in these outcomes. Does an incomplete periacetabular acetabuloplasty, as an added step to delayed open reduction, (1) diminish the risk of developing acetabular dysplasia; or (2) increase the rate of AVN compared with patients treated with open reduction alone? We conducted a retrospective matched case-control study comparing 22 patients (27 hips) with early isolated DDH who underwent intentionally delayed open reduction and acetabuloplasty from 2004 to 2010 and followed up > 4 years (88% of the cohort) with early historic controls treated with delayed open reduction alone. Of 53 patients available for matching, 45 (85%) had enough followup (> 10 years) to be considered. They were matched one to one for age at presentation and bilaterality (fuzz 45, 0). This generated a control group of 25 patients (27 hips). The mean followup was different between the groups (p < 0.001). Residual dysplasia considered when center-edge angle < 15° (6-13 years old) or < 20° (≥ 14 years old) or as a nonevolving acetabular index > 30° and pelvic osteotomies were used as our primary outcomes. The proportion of patients with AVN was also compared. Patients treated with open reduction and an incomplete periacetabular acetabuloplasty were less likely to develop acetabular dysplasia and undergo pelvic osteotomies than were patients in the control group (0% [zero of 27] versus 37% [10 of 27]; odds ratio [OR], 11; 95% confidence interval [CI], 2-80; p = 0.02 and 0% [zero of 27] versus 26% [seven of 27]; OR, 8; 95% CI, 1-60; p = 0.025, respectively). With the available numbers, there was no difference in terms of the proportion of patients who developed AVN (11 of 27 [41%] both groups; OR, 1; 95% CI, 1-2; p = 1). The addition of an incomplete periacetabular acetabuloplasty to all hips undergoing open reduction eliminated residual acetabular dysplasia, whereas it did not appear to have deleterious effects as evidenced by the similar AVN proportion. Level III, therapeutic study.

Introduction. The proper application of pelvic osteotomies for the surgical treatment of developmental dysplasia of the hip (DDH) plays a key role in correcting acetabular dysplasia and preventing secondary hip osteoarthritis. For the correct application of pelvic osteotomies, it is mandatory to understand the three-dimensional morphology of the acetabulum and accurately determine the direction of acetabular dysplasia correction. Currently, there is no described pelvic osteotomy, which can improve femoral head coverage in any direction without significant technical limitations. Objective. This study aims to evaluate the outcomes of the modified Salter pelvic osteotomy performed at the Department of Reconstructive Orthopedics and Traumatology for Children and Adolescents at the SI “Institute of Traumatology and Orthopedics of NAMS of Ukraine.” Materials and Methods. 21 patients with DDH aged 2-6 years were selected for the retrospective study; 3-D acetabular morphology was assessed with further application of the proposed modified Salter osteotomy for correcting acetabular dysplasia. Results. A methodology for assessing the 3-D morphology of the acetabulum and determining the correction vectors for acetabular dysplasia was developed and implemented; the mid-term postoperative results after applying the proposed modification of Salter pelvic osteotomy were evaluated. The modification demonstrated significant improvement in acetabular parameters: preoperative acetabular index (AI) was 46.8 ± 12°, postoperative AI was 24.3 ± 5.1°, with a mean correction of 23.1 ± 4.9°. Further positive dynamics were observed: AI at 6 months postoperatively was 19.8 ± 4.7°, and at the final follow-up examination, it reached 15.6 ± 4.4°, while Wiberg’s angle improved to 23.3 ± 3.9°. Excellent and good clinical outcomes were observed in 57.2% and 33.3% of cases, respectively, with radiological outcomes showing excellent and good results in 66.7% and 23.8% of cases. A relatively high rate of femoral head avascular necrosis (AVN) (33.3%) correlated with a high percentage of patients with complete hip dislocation (61.9%). However, most patients with AVN (23.8%) subsequently experienced near-complete or complete restoration of femoral head structure and shape. Conclusions. 3-D acetabular morphology assessment is a key factor for the successful surgical correction of residual acetabular dysplasia in DDH cases. The proposed modification of the Salter pelvic osteotomy provides excellent and good mid-term clinical and radiological outcomes in most cases.

Acetabular underdevelopment (acetabular dysplasia) is a common finding in children with hip dislocation, and residual acetabular dysplasia can remain after hip reduction. Residual dysplasia leads to unsatisfactory long-term outcomes and osteoarthritis. Dynamics of acetabular dysplasia [measured as Acetabular Index (AI)] in a pediatric cohort that underwent open (OR) or closed reduction are reported. Retrospective data from six tertiary pediatric orthopedic centers were gathered. Hips were classified as having 'Critical', 'Monitoring', or 'Normal' acetabular dysplasia based on age-adjusted normative AI measurements. From 193 hips, 108 (56%) underwent open reduction. Children younger than 24 months had a strong AI decline but children > 24 months did not. Among 78 hips with critical dysplasia at time of OR, 36 (46.2%) remained critical and 19 (24.4%) underwent an acetabular osteotomy (AO) during follow-up. CR hips had a similar AI decline in patients younger and older than 12 months. Among 51 hips with critical dysplasia at the time of CR, 13 (25.5%) remained critical and 21 (41.2%) underwent AO during follow-up. Acetabular dysplasia improves with AI decreasing in children who undergo OR and CR under the age of 2 years with slower acetabular remodeling afterwards. Around 2/3 of patients with AI in the critical range at CR or OR either underwent AO or had significant acetabular dysplasia at final follow-up. Our data supports considering simultaneous AO at the time of OR for hips with AI in the critical range or children who undergo hip open reduction after 24 months of age. Level of Evidence: Level III.

Developmental dysplasia of the hip (DDH) is a complex disorder that refers to different hip problems, ranging from neonatal instability to acetabular or femoral dysplasia, hip subluxation, and hip dislocation. It may result in structural modifications, which may lead to early coxarthrosis. Despite identifying the risk factors, the exact aetiology and pathophysiology are still unclear. Neonatal screening, along with physical examination and ultrasound, is critical for the early diagnosis of DDH to prevent the occurrence of early coxarthrosis. This review summarizes the currently practised strategies for the detection and treatment of DDH, focusing particularly on current practices for managing residual acetabular dysplasia (AD). AD may persist even after a successful hip reduction. Pelvic osteotomy is required in cases of persistent AD. It could also be undertaken simultaneously with an open hip reduction. Evaluation of the residual dysplasia (RD) of the hip and its management is still a highly active area of discussion. Recent research has opened the door to discussion on this issue and suggested treatment options for AD. But there is still room for more research to assist in managing AD.

Background:After reduction of developmental hip dislocations, residual dysplasia is common with rates of secondary reconstructive surgery with pelvic osteotomy ranging from 19% to 60%. The determination and timing of when to proceed with surgery is difficult as acetabular remodeling occurs gradually over the first few years after reduction. The purpose of this study was to evaluate how age at secondary reconstructive surgery influences the clinical and radiographic outcomes after pelvic osteotomy for residual dysplasia.Methods:After IRB approval, we retrospectively reviewed all isolated Salter or Pemberton pelvic osteotomies performed for residual dysplasia after an index closed or open reduction at a single institution between 1983 and 2020 with radiographic follow-up through skeletal maturity. Acetabular index (AI) and migration index (MI) were measured on preoperative, immediate postoperative, and 2-year follow-up radiographs. After triradiate cartilage closure, anterior-posterior pelvis radiographs were measured for lateral center-edge angle (LCEA), Tönnis angle, MI, and lateralization ratio (LR). Univariate and multivariate analysis were used to evaluate outcomes based on age at time of surgery.Results:Ninety-two hips from 83 patients were included. 55 Salter (60%) and 37 Pemberton osteotomies (40%) were performed with mean age at surgery of 5.2±1.7 years. 46% (42/92) hips across both treatment groups had residual dysplasia (LCEA<25 deg.) at final follow-up (mean age 15±3.2 y). However, there was no significant difference in acetabular dysplasia at 2 years postop or after triradiate closure between those hips treated before or after 5 years of age (all P>0.05). Multivariate analysis revealed that only the immediate postoperative MI predicted the final follow-up LCEA (P<0.01), although the rate of dysplasia was still 24% in the most covered hips (MI<10%).Conclusions:Even after pelvic osteotomy for residual dysplasia, there are high rates of dysplasia at skeletal maturity. Only the femoral head coverage achieved, not the age at time of surgery, predicted dysplasia at skeletal maturity. These findings suggest that there is no opportunity cost to short-term continued observation while monitoring for acetabular remodeling.Level of Evidence:Level III.

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

ObjectivesThe aim of this study was to evaluate correlation of post-reduction magnetic resonance imaging (MRI)-based parameters with residual acetabular dysplasia in developmental dysplasia of the hip (DDH) patients who underwent open reduction.Patients and methodsA total of 62 hips of 54 children (5 males, 57 females; mean age: 8.5±3.5 months; range, 0 to 24 months) with a diagnosis of DDH who underwent open reduction between January 2012 and January 2017 were retrospectively analyzed. The acetabular head index (AHI), head coverage index (HCI), sphericity, bony acetabular index (BAI), cartilage acetabular index (CAI), anterior acetabular index (AAI), posterior acetabular index (PAI), abduction angle (AA), and acetabular medial wall thickness were measured by MRI. The correlation between MRI measurements and residual acetabular dysplasia was evaluated.ResultsThe mean follow-up was 23.7±10.1 (range, 12 to 56) months. The mean age at the final examination was 47.6±10.4 months. The age at the time of operation (r=0.250, p=0.049), medial wall thickness (r=0.304, p=0.016), AAI (r=0.729, p<0.001), PAI (r=0.590, p<0.001), and early postoperative AI (r=0.900, p<0.001) at the third postoperative month were positively correlated with the last follow-up AI. The AHI (r=-0.512, p<0.001), sphericity (r=-0,661, p<0.001), and HCI (r=-0.554, p <0.001) were negatively correlated with the last follow-up AI.ConclusionPost-reduction MRI parameters can be used to evaluate correlation with persistent acetabular dysplasia in DDH patients.

BackgroundPelvic and femoral osteotomies have been effective methods to treat developmental dysplasia of the hip (DDH), neurogenic dislocation of the hip (NDH), and Legg–Calvé–Perthes disease (LCPD). The aim of this study was to evaluate the mid-term results after hip reconstruction in children with DDH, NDH, and LCPD.MethodsIn a retrospective study, X-rays of 73 children (2–19 years) with DDH, NDH, and LCPD were measured before, 3 months, and at final follow-up (FU) after hip reconstructive surgery (open reduction, and femoral and/or pelvic osteotomy ± soft-tissue procedures between 2008 and 2018). Measurement of hip geometry included acetabular index (AI), center-edge angle (CE), and Reimers migration index (RMI). Mean follow-up time at final FU was 4.9 years. P value was set P < 0.05.ResultsAfter surgery (femoral osteotomy: 84 hips, Salter innominate osteotomy: 21 hips, Pemberton osteotomy: 30 hips, open reduction: 28 hips, Chiari osteotomy: 4 hips, and soft-tissue release: 24 hips), hip geometry parameters improved significantly. Nevertheless, at final FU, there was deterioration in hip geometry with femoral head lateralization (RMI) compared to the data at 3 months after surgery (RMI: preop/3 months/final FU: 40.6 ± 16.1%/6.1 ± 9.0/15.4 ± 16.0%; CE: 11.3° ± 20.0°/30.2° ± 9.5°/27.9 ± 15.4°; AI: 28.8° ± 9.6°/19.1° ± 7.6°/18.3 ± 7.6°). Sub-group analysis did not show differences concerning the progression of RMI in DDH, NDH, and LCPD at final FU. Regardless of basic disease, the lateralization was observed in all three groups (DDH, NDH, and LCPD) and statistically significant comparing X-rays 3 months postoperatively to maximum follow-up (DDH; NDH; LCPD: 2.7 ± 6.8%/7.6 ± 10.1%; 13.7 ± 15.3%/22.8 ± 19.8%; 1.7 ± 4.1%/14.9 ± 11.3%). Additional soft-tissue release techniques in patients with DDH or NDH did not show postoperative differences with statistical significance. Concerning surgical techniques, a connection between the lower RMI and the procedure of osteotomy of the ilium was found. In 25 patients, (34%) complications were observed: superficial skin lesions in 8, deep skin lesions in 3, contraction of adductors in 3, subluxation in 2, dislocations of the cast in 2, osteonecrosis of the femoral head in 2 cases, reluxation in 1, infection of the implanted plate in 1, compliance problem in 1, delayed bone healing in 1, and contraction of knee flexors in 1 case.DiscussionThe basic results of this study show a significant improvement of hip geometry at a follow-up of 4.9 years and prove findings of previously published literature. Moreover, the study was able to show a progression of RMI in all patient groups, which have undergone reconstructive surgery, despite basic hip geometry data (AI, CE angle) did not change. Those findings were independent from underlying pathology. Complications were counted in 34% of the patients and involved all known adverse events after hip reconstructive surgery. This makes clear why annual follow-up checks are needed not to miss the right indication for revision surgery.Clinical relevanceEvidence level: Level IV, case series.Trial registration: This manuscript is part of a prospective randomized clinical trial, registered in the German Clinical Trials Register DRKS-ID: DRKS00016861.

What's New in Pediatric Orthopaedic Surgery.

To determine the incidence of residual dysplasia after closed reduction (CR) of developmental dysplasia of the hip (DDH) and assess correlations between quality of arthrogram-guided CR and residual dysplasia using a new intraoperative radiographic criterion. Data of a consecutive series of 126 patients with DDH in 139 hips treated at our institution by arthrogram-guided CR from March 2006 to June 2013 were reviewed in this retrospective study. There were 23 boys and 103 girls with 88 affected left hips and 51 right hips. The average age at closed reduction was 14 months (range, 7-19 months) and average duration of follow-up 36 months (range, 24-100 months). Femoral head coverage (FHC) and arthrography type (A/B/C) on best reduced arthrographic images, acetabular index (AI) and Wiberg Center-Edge (CE) angle on anteroposterior (AP) pelvis radiograph at latest follow-up were measured. Residual hip dysplasia was determined according to the Harcke acetabular dysplasia radiographic standard. Patients were divided into non-late acetabular dysplasia (non-LACD) and late acetabular dysplasia (LACD) groups according to final results and age at reduction, sex and side compared between these two groups. Correlations between FHC and arthrography type and residual hip dysplasia were analyzed. Multiple logistic regression analysis was used to analyze sex, AI at CR, arthrography type and FHC with LACD. Receiver operating characteristic (ROC) curve analysis was used to determine the cutoff value for FHC. Forty-five of 139 hips (32.4%) had residual hip dysplasia. Avascular necrosis of the femoral head occurred in 11 hips (7.9%), nine of which had acetabular dysplasia. There were no significant differences between the two groups in age at reduction, sex or side. FHC differed significantly between the two groups (51.2% ± 15.3% vs . 28.5% ± 15.9%, t = 4.718, P = 0.000). A significantly greater percentage of the arthrography Type C group than Type A and B groups had LACD (χ(2) = 17.170, P = 0.017). According to multiple logistic regression analysis, FHC was the only prognostic factor for LACD. There was a clear cutoff value for FHC (30%), under which 81.8% hips were determined as having LACD according to ROC curve analysis. Intraoperative arthrogram-determined FHC is an alternative predictor of residual hip dysplasia after CR of DDH and FHC ≤30% can be considered the criterion for unacceptable reduction.

Purpose:The purpose of the study was to compare the post-reduction magnetic resonanceimaging morphology for hips that developed residual acetabular dysplasia,hips without residual dysplasia, and uninvolved contralateral hips inpatients with unilateral developmental dysplasia of the hip undergoingclosed or open reduction and had a minimum 10-year follow-up.Methods:Retrospective study of patients with unilateral dysplasia of the hip whounderwent open/closed hip reduction followed by post-reduction magneticresonance imaging. Twenty-eight patients with a mean follow-up of13 ± 3 years were included. In the treated hips, residual dysplasia wasdefined as subsequent surgery for residual acetabular dysplasia or forSeverin grade > 2 at latest follow-up. On post-reduction, magneticresonance imaging measurements were performed by two readers and comparedbetween the hips with/without residual dysplasia and the contralateraluninvolved side. Magnetic resonance imaging measurements included acetabularversion, coronal/ axial femoroacetabular distance, acetabular depth–widthratio, osseous/cartilaginous acetabular indices, and medial/lateral (limbus)cartilage thickness.Results:Fifteen (54%) and 13 (46%) hips were allocated to the “no residual dysplasia”group and to the “residual dysplasia” group, respectively. All eightmagnetic resonance imaging parameters differed between hips with residualdysplasia and contralateral uninvolved hips (all p < 0.05). Six of eightparameters differed (all p < 0.05) between hips with and without residualdysplasia. Among these, increased limbus thickness had the largest effect(odds ratio = 12.5; p < 0.001) for increased likelihood of residualdysplasia.Conclusions:We identified acetabular morphology and reduction quality parameters that canbe reliably measured on the post-reduction magnetic resonance imaging tofacilitate the differentiation between hips that develop with/withoutresidual acetabular dysplasia at 10 years postoperatively.Level of evidence:level III, prognostic case-control study.

The sequelae of open reduction of developmental and/or syndromic hip dislocations include osteonecrosis/proximal femoral growth disturbance and residual dysplasia. There is limited information comparing the rates of these sequelae in patients with developmental dysplasia of the hip (DDH) and arthrogryposis multiplex congenita (AMC). We performed a dual-center retrospective cohort study to compare rates of proximal femoral growth disturbance and residual dysplasia between patients with DDH and AMC who had undergone open hip reduction for the treatment of non-traumatic hip dislocations. We identified patients <18 years of age who had undergone open reduction for the treatment of hip dislocation between 1981 and 2020 at 2 tertiary pediatric hospitals. Patients with AMC were matched by age against patients with DDH in a 1:2 ratio. Preoperative data included demographic characteristics, the severity of dislocation according to the International Hip Dysplasia Institute (IHDI) classification system, and the acetabular index. Outcomes included the acetabular index at 2 years postoperatively, the IHDI classification at the time of final follow-up, and the presence and grade of proximal femoral growth disturbance according to the Salter criteria at 2 years postoperatively and according to the Kalamchi and MacEwen (KM) classification system at the time of final follow-up. Eighty-two patients (98 hips) with DDH were matched against 39 patients (49 hips) with AMC. The mean follow-up was 107 months (range, 24 to 443 months). There was no difference in the mean age at surgery (1.5 ± 0.7 versus 1.4 ± 1.3 years; p = 0.86), preoperative IHDI classification, acetabular index, or spica cast duration (p > 0.05 for all), but the DDH cohort had more females (83% versus 56%; p = 0.003). Postoperatively, the prevalence of proximal femoral growth disturbance was higher in the AMC group than in the DDH group according to the Salter criteria at 2 years (57% versus 21%; p < 0.001) and according to the KM criteria at the time of final follow-up (59% versus 16%; p < 0.001). At 2 years postoperatively, there was no difference between the DDH and AMC groups in terms of the acetabular index (31° ± 6.2° versus 29° ± 6.9°; p = 0.3) or reoperation rate (24% versus 20%; p = 0.68), but the AMC cohort had more IHDI grade II-IV hips than the DDH cohort (24% versus 9%; p = 0.02), reflecting re-subluxation/dislocation. Open reduction for hip dislocation in patients with AMC was associated with a significantly higher rate of proximal femoral growth disturbance and re-subluxation/dislocation compared with that in patients with DDH, despite similar preoperative characteristics. This information may guide perioperative counseling for families of patients with AMC. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

This study aimed to investigate the radiographic outcomes, rate of redislocation, and avascular necrosis of proximal femoral epiphysis (AVN) in patients aged 24 to 36months with developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization in human position. We reviewed the medical records of 39 patients (51 hips) aged 24 to 36months with DDH treated by CR and spica cast immobilization in human position. The Tönnis grade, rate of redislocation and AVN, acetabular index (AI), centre-edge angle (CEA), and Severin radiographic grade were evaluated on plain radiographs. Among the included 39 patients (51 hips), 15 hips (29.4%) were Tönnis grade II, 24 hips (47.1%) were grade III, and 12 hips (23.5%) were grade IV. In 47 hips (92.2%), the ossific nucleus was present at the time of CR. Stable reduction was achieved by CR in 39/51 hips (76.5%) and redislocation occurred in 12/51 hips (23.5%). Among the 12 hips that redislocated, 11 underwent open reduction and one repeated CR. Two out of 40 hips (5%) treated by CR developed AVN. Overall, 54.6% of the hips had satisfactory outcomes (39.2% Severin type I and 17.6% type II), while 45.4% had unsatisfactory outcomes (39.2% Severin type III and 3.9% type IV). Of the 40 hips treated by CR, 57.5% and 42.5% of cases had satisfactory outcomes and residual acetabular dysplasia, respectively. Six out of 11 hips (54.6%) treated by open reduction and pelvic osteotomy had satisfactory outcomes. Our study showed that stable CR could be achieved in 76.5% of patients aged 24 to 36months with DDH at the time of index procedure. Satisfactory outcomes can be expected in 56.4% of the cases (5.0% AVN rate), although late acetabular dysplasia may develop in 43.6% of the hips.

PurposeThe anterior and medial approaches in open reduction for developmental dysplasia of the hip (DDH) had been widely used. The former could not directly approach the intra-articular interposition, while the latter had been associated with injury to blood vessel and avascular necrosis (AVN) of the femoral head. Meanwhile, the bikini incision had also been mentioned in some studies. The purpose of this study was to introduce a modified anterior approach through a mini-bikini incision and report its short-term outcomes.MethodsData of DDH patients younger than 2 years at the time of surgery who had received this mini-bikini incision between June 2013 and December 2018 were collected. The surgical technique, operation duration, intraoperative blood loss, and length of incision were recorded in detail. In the latest follow up, the objective measurement of the scar and the subjective feeling towards the scar were collected. X-ray and magnetic resonance imaging (MRI) were performed at the last follow-up, and the incidence of residual dysplasia, redislocation, and femoral head AVN was analyzed.ResultsForty-three cases (49 hips) were included with an averaged follow-up of 43 months. The operation duration was 22 min, and the blood loss was 9.8 ml on average. The length of the scar averaged 2.6 cm. The mean University of North Carolina “4P” scar scale (UNC4P) for the scar was 0.92, and no patients complained numbness. Overall, all the parents were satisfied with the cosmetic appearance. The mean acetabular index (AI) was 27.42° ± 6.41° in dislocated hip in the last follow-up. One hip redislocated soon after the operation and was reduced in a closed manner right away. MRI showed improved coverage but still some residual dysplasia that was in accordance with the post-operative recovery nature. Four hips (8%) had signs of AVN in X-ray.ConclusionOpen reduction through the anterior approach with the mini-bikini incision was a safe procedure with comparable outcomes to classical approaches. It would be a complementary approach for DDH patients younger than 2 years old who need an open reduction.