A Prospective, Multicenter Study of Developmental Dysplasia of the Hip: What Can Patients Expect After Open Reduction?

Open Reduction of Hip Dislocation Is Associated with Higher Rates of Proximal Femoral Growth Disturbance in Patients with Arthrogryposis Multiplex Congenita Than Idiopathic DDH: A Dual-Center Retrospective Cohort Study

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

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

Long-Term Results After Salter Innominate Osteotomy for the Treatment of Developmental Dysplasia of the Hip-Only 8% Rate of Total Hip Arthroplasty at a Median Follow-Up of 22 Years

BACKGROUND/OBJECTIVES

The redirection or reshaping of the acetabulum might be warranted to attain a concentric and stable hip in children with developmental dysplasia of the hip (DDH). The aim of this study is to assess the late clinical and radiological results, and to determine the number of patients requiring secondary surgery or a total hip arthroplasty at a long-term follow-up.

METHODS

Our institution performed 99 Salter osteotomies on 76 patients without underlying neuromuscular conditions over a 21-year period, from 1981 to 2002. These procedures were carried out by three different surgeons. Patients underwent a comprehensive evaluation at the review visit, including a physical examination, clinical assessments using the Harris hip score (HHS), Oxford score (OHS) and Visual Analogue Scale (VAS) pain score, as well as pelvic radiographs.

RESULTS

At a median follow-up of 22 years, total hip arthroplasty was performed in 6 out of 77 hips (8%). Patients who underwent a Salter osteotomy with an open reduction had a higher rate of avascular necrosis (AVN) of the femoral head compared to those who only underwent a Salter pelvic osteotomy (p < 0.001). There were statistically significant differences in the group with and without AVN in terms of HHS (p = 0.006, 95%CI 0.003 to 0.006), OHS (p = 0.016, 95%CI 0.012 to 0.017), a modified OHS (p = 0.018, 95% CI 0.012 to 0.016), a VAS score in activity (p = 0.046, 95%CI 0.042 to 0.050) and VAS score satisfaction (p = 0.005, 95%CI 0.003 to 0.006).

CONCLUSIONS

The rate of THA was 8% at a mean of follow-up of 22 years. Secondary results suggest that AVN occurs more frequently when a Salter osteotomy is combined with an open reduction. The occurrence of AVN is associated with significantly lower clinical outcome scores and patient satisfaction, as well as significantly higher pain scores. In the absence of AVN, good clinical results can be expected at long-term follow-up.

Prevalence and Risk Factors for Stiffness Following Open Reduction for Developmental Dysplasia of the Hip

OBJECTIVE

Most prior investigations on adverse outcomes after open reduction (OR) for developmental dysplasia of the hip (DDH) have focused on avascular necrosis, redislocation, and residual dysplasia. To our knowledge, no previous study has investigated risk factors for stiffness, an underappreciated source of postoperative morbidity. The goals of this study were to define the entity more clearly and evaluate the prevalence and risk factors for arthrofibrosis after OR for DDH.

METHODS

A retrospective study was conducted, including all open hip reductions for DDH performed by a single surgeon from 2009 to 2022. Preoperative anteroposterior pelvic radiographs were used to calculate superior displacement, which was defined as the distance from the highest point of the proximal femoral metaphysis to the Hilgenreiner line, normalized by pelvic width. Cases treated with premature postoperative bracing cessation and/or referral to physical therapy with a resolution of stiffness within 6 months were categorized as mild arthrofibrosis. Cases that required >6 months of formal physical therapy for persistent range of motion concerns, manipulation under anesthesia, and/or inpatient rehabilitation admission were categorized as significant arthrofibrosis.

RESULTS

This study included 170 hips with a mean age of 21.6 months (range: 6.1 to 93.6 mo) and a mean follow-up of 46.8 months. 156 ORs (91.8%) were done through an anterior approach. Sixty-four patients (37.6%) had a concomitant isolated pelvic osteotomy, and 34 (20.0%) had both pelvic and femoral osteotomies. During the postoperative course, 109 patients (64.1%) had no arthrofibrosis, 38 (22.4%) had mild stiffness, and 23 (13.5%) had significant arthrofibrosis. On multivariable analysis, older age, superior displacement, and concomitant pelvic osteotomy were associated with any degree of arthrofibrosis ( P < 0.05). Children older than 18 months or with dislocations higher than 16% of pelvic width had a 4.7 and 2.7 times higher risk, respectively, of experiencing some degree of stiffness postoperatively.

CONCLUSIONS

Older age, high dislocations, and concomitant pelvic osteotomy without femoral shortening are risk factors for stiffness after OR for DDH. Surgeons should counsel families about the risk of postoperative stiffness, which occurred to some degree in 36% of our patients.

LEVEL OF EVIDENCE

Level IV.

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.

Intraoperative 3D Fluoroscopy During Open Reduction for DDH: An Effective Alternative to Postoperative CT/MRI

BACKGROUND

Computed tomography CT or magnetic resonance imaging (MRI) has been the most used imaging modality to assess hip reduction in developmental dysplasia of the hip (DDH) after open reduction (OR). In 2015, intraoperative 3D fluoroscopy (3D) was introduced at our center as an alternative to CT/MRI. 3D offers the advantage that if hip reduction is insufficient, it can be addressed at the time of surgery. The purpose of this study was to assess the efficacy of 3D in comparison to CT/MRI.

METHODS

This was a single-centre, retrospective comparative study of two consecutive cohorts: those with OR and 3D between 2015 and 2017 and those with OR and CT/MRI between 2012 and 2014. Time to imaging, re-imaging, length of stay (LOS), re-operation, and redislocation or subluxation after cast removal were evaluated.

RESULTS

Forty-two patients (46 hips) had 3D, and 30 patients (32 hips) had CT/MRI. Significant differences were found between groups in time to imaging, cast changes, and LOS. All 3D was intraoperative (46 hips), and only 69% (22 hips) of CT/MRI was on the day of surgery ( P <0.01). In the 3D group, 1 hip (2%) had a cast change under the same anesthetic, and 4 hips (13%) from CT/MRI had cast changes in subsequent surgery ( P =0.03). The mean LOS in days for 3D was 1.72 and 2.20 for CT/MRI ( P =0.03). There were no statistically significant differences between groups in further imaging and subluxations or re-dislocations at cast removal. Two hips (4%) in the 3D group had MRI, but with no further intervention ( P =0.51), and at cast removal, there were 3 subluxations in each group ( P =0.69) and 1 redislocation in the 3D group ( P =1.00).

CONCLUSIONS

Intraoperative 3D improved time to imaging, allowed for cast changes at surgery and had a shorter LOS. Moreover, there were no significant differences found in adverse outcomes between those who underwent 3D versus CT/MRI. 3D should thus be considered an effective alternative to CT/MRI for assessing hip reduction during OR for DDH.

LEVEL OF EVIDENCE

Diagnostic Study, level II.

Arthroscopic debridement and reduction is an effective procedure for failed closed reduction in young children with developmental dislocation of the hip

PURPOSE

To assess the efficacy of arthroscopic debridement and reduction through two medial portals for the treatment of developmental dislocation of the hip (DDH) with failure of initial closed reduction and to explore key pathological structures obstructing reduction.

METHODS

Forty-eight children with 58 irreducible dislocated hips treated by arthroscopic reduction between January 2017 and December 2020 were retrospectively evaluated. Arthroscopic reduction was performed via two medial portals located in the superior and inferior adductor longus. All intra-articular obstacles were eliminated via arthroscopy, followed by manual reduction and spica cast immobilization. The surgical duration, extent of improvement in the safe zone, and extent of secondary surgical treatment were noted. All the children were followed up for > 24 months. Hip function and radiographic outcomes were evaluated.

RESULTS

All 58 hips showed safe zone improvement and concentric reduction after arthroscopic debridement. Hypertrophic ligamentum teres and thickened pulvinars were detected and resected in all hips. Constrictive capsules preventing reduction were observed in 15 hips, which needed to be further released. No inverted labrum was observed. Secondary surgery was performed in four hips with redislocation and seven hips with subluxation during follow-up. The remaining 47 hips (81.03%) maintained their reduction at the last follow-up. Excellent and good clinical outcomes were achieved in 95.74% of patients according to McKay's criteria. Two hips, three hips, and one hip were diagnosed with grade I, II, and III osteonecrosis of the femoral head, respectively.

CONCLUSION

This study demonstrated that arthroscopic debridement and reduction is a safe and feasible choice for treating irreducible DDH.

Preoperative Gallows traction as an adjunct to hip open reduction surgery: Is it safe and is it effective?

Background

Traction is used at our hospital before open reduction in infants with developmental dysplasia of the hip. Theoretically, it reduces soft-tissue tension, allowing an easier surgical reduction and therefore lower surgical complications. Owing to extended hospital stays, potential complications, and lack of evidence, the use of traction has decreased. This study aims to quantify whether traction is safe and whether it has any demonstrable effect.

Methods

The perioperative course of 80 patients undergoing preoperative traction and hip open reduction were reviewed. The height of hip dislocation was classified using the International Hip Dysplasia Institute classification system on both radiographs taken before and after traction. Any complications related to traction were recorded, along with the requirement for femoral shortening osteotomies, incidence of re-dislocation, and longer-term rate of avascular necrosis.

Results

Traction lowered the resting position of the majority of hips, with the median International Hip Dysplasia Institute grade before traction improving from 4 to 3, a statistically significant improvement (p < 0.00001). There were no neurovascular complications. Two babies were complicated with broken skin sores; however, surgery still progressed uneventfully. Zero hips in the cohort required femoral shortening osteotomies to achieve a tension-free reduction, and the re-dislocation rate was 0%. However, 96% of hips were Severin 1 or 2 at 6-year follow-up.

Conclusion

Notably, 1 week of preoperative traction significantly improves the resting position of the hip in high dislocations. It is safe when used in infants weighing <12 kg, and subsequent surgical outcomes are excellent, thus supporting its use ahead of developmental dysplasia of the hip open reduction surgery.

Level of evidence

Level IV.

Femoral Head Remodeling After Surgical Reduction of Developmental Hip Dislocations

OBJECTIVE

Developmental dysplasia of the hip is prevalent and is associated with dysplasia of both the femoral head and acetabulum. There is a paucity of literature describing femoral head remodeling after surgical reduction of developmentally dislocated hips. The purpose of this study was to describe and quantify changes in femoral head sphericity after closed or open reduction for developmental dysplasia of the hip.

METHODS

A retrospective cohort study was performed including patients with typical developmental hip dislocations who underwent closed or open reduction from 2009 to 2022 at a single institution and had immediate postoperative and average 3-week follow-up magnetic resonance imaging (MRI) scans. A subset of patients also had 3-year follow-up MRI scans. Patients with insufficient imaging or bony procedures at the time of reduction were excluded. We developed a technique to quantify femoral head "sphericity" by comparing differences in measured radii of the femoral head on axial and coronal plane MRI slices. We then calculated the variance of the radii for each plane and averaged these to calculate a combined variance. The variance was used to represent "sphericity," with a larger variance indicating a wider distribution of radii and thus a less spherical shape.

RESULTS

A total of 74 patients (69 females) with 96 hips were included in this series. The median age of the child at the time of reduction was 8.7 months [interquartile range (IQR): 2.2]. Over half (58.3%) of the hips had a closed reduction, whereas the remaining were open reduced (41.7%). Immediately postoperatively, at the 3-week time point, and at the 3-year time point the median combined variance was 1.1 (IQR: 3.93), 0.51 (IQR: 1.32), and 0.31 (IQR: 0.50), respectively, indicating improved sphericity over time.

CONCLUSIONS

Sphericity of the femoral head in developmental hip dislocations improves in both the immediate postoperative period, as well as the first few years after reduction. Further research is needed to evaluate the mechanism of remodeling, the ideal timing of reduction, and the relationship between femoral head and acetabular remodeling.

LEVEL OF EVIDENCE

Level IV-case series, therapeutic study.