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

Protective effect of modified lange "second position" for developing avascular necrosis following closed reduction for developmental dysplasia of the hip

BACKGROUND

Developmental Dysplasia of the Hip (DDH) is a condition affecting hip joint development in children, presenting multiple manifestations. Immobilization methods to ensure hip concentricity, such as the human position and modified Lange position, vary in effectiveness and risks, especially avascular necrosis. The purpose of this study was to identify whether closed reduction (CR), with two different immobilization techniques, is effective in avoiding complications such as residual hip dysplasia (RHD), re-dislocation, and Avascular Necrosis (AVN).

METHODS

A total of 66 patients with DDH (84 hips) were treated with two different techniques of immobilization (groups A and B); the mean age at the time of reduction was 8 (6-13) months. The rates of RHD, Re-dislocation, and AVN were determined with a minimum follow-up of 48 months in both techniques.

RESULTS

The Chi-square analysis conducted across the study groups unveiled that patients in Group B demonstrated a protective effect against AVN compared to those in Group A (OR: 0.248, 95% CI: 0.072-0.847, p = 0.026). However, no statistically significant differences were found between the groups concerning RHD (p = 0.563) and re-dislocation (p = 0.909).

CONCLUSIONS

After the initial Human Position immobilization, the second cast with the modified Lange "second position" demonstrated a protective effect compared with maintaining the Human Position immobilization throughout the immobilization period, reducing the likelihood of AVN development in patients undergoing closed reduction for developmental dysplasia of the hip.

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

Aim

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.

Methods

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.

Results

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).

Conclusion

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.

Outcome Prognostic Factors in MRI during Spica Cast Therapy Treating Developmental Hip Dysplasia with Midterm Follow-Up

Closed reduction followed by spica casting is a conservative treatment for developmental dysplasia of the hip (DDH). Magnetic resonance imaging (MRI) can verify proper closed reduction of the dysplastic hip. Our aim was to find prognostic factors in the first MRI to predict the possible outcome of the initial treatment success by means of ultrasound monitoring according to Graf and the further development of the hip dysplasia or risk of recurrence in the radiological follow-up examinations. A total of 48 patients (96 hips) with DDH on at least one side, and who were treated with closed reduction and spica cast were included in this retrospective cohort study. Treatment began at a mean age of 9.9 weeks. The children were followed for 47.4 months on average. We performed closed reduction and spica casting under general balanced anaesthesia. This was directly followed by MRI to control the position/reduction of the femoral head without anaesthesia. The following parameters were measured in the MRI: hip abduction angle, coronal, anterior and posterior bony axial acetabular angles and pelvic width. A Graf alpha angle of at least 60° was considered successful. In the radiological follow-up controls, we evaluated for residual dysplasia or recurrence. In our cohort, we only found the abduction angle to be an influencing factor for improvement of the DDH. No other prognostic factors in MRI measurements, such as gender, age at time of the first spica cast, or treatment involving overhead extension were found to be predictive of mid-term outcomes. This may, however, be due to the relatively small number of treatment failures.

Evaluation of avascular necrosis risk factors after closed reduction for developmental dysplasia of the hip before walking age

Avascular necrosis (AVN) of the femoral head is one of the most important complications after closed reduction and spica cast application in developmental dysplasia of the hip (DDH) treatment. This study aims to put forth the impact of closed reduction age and other factors which can cause AVN. Inclusion criteria of the study were: closed reduction and spica cast application before walking age (12 months) and minimum 2 years duration of follow-up. The presence of femoral head ossific nucleus, International Hip Dysplasia Institute (IHDI) score, acetabular indices and AVN were evaluated from radiographies. Hip abduction angles were evaluated on CT images. The absence of the ossific nucleus at the closed reduction time and preoperative IHDI grade were not significant risk factors for AVN (respectively OR = 2.83; 95% CI, 0.99-8.07; P = 0.052; OR = 2.5; 95% CI, 0.85-7.32; P = 0.094). For the patients older than 10 months, (1) the absence of the ossific nucleus was a significant risk factor for grade 2 or higher AVN according to the Bucholz Ogden criteria (P = 0.020) and (2) the higher preoperative IHDI grade (IHDI 3-4) was a significant risk factor for AVN (P = 0.032). AVN of the femoral head was a significant risk factor for fair or poor clinical outcome (P = 0.001). It is not reasonable to wait for radiological visibility of the ossific nucleus to prevent femoral head AVN before applying closed reduction and spica cast, irrespective of the age interval.

Developmental dysplasia of the hip: can contrast-enhanced MRI predict the development of avascular necrosis following surgery?

OBJECTIVE

To investigate the performance of contrast-enhanced MRI for predicting avascular necrosis (AVN) of the treated femoral head after surgical reduction for developmental dysplasia of the hip (DDH) using qualitative and quantitative methods.

METHODS AND MATERIALS

This IRB-approved, HIPAA compliant retrospective study included 47 children who underwent same-day contrast-enhanced MRI following unilateral surgical hip reduction between April 2009 and June 2018. Blinded to the clinical outcome, 3 reviewers (2 pediatric radiologists and 1 pediatric orthopedist) independently categorized the enhancement pattern of the treated femoral head. Signal intensities, measured using regions of interest (ROI), were compared between treated and untreated hips and percent enhancements were compared between hips that developed and did not develop AVN. Post-reduction radiographs were evaluated using Salter's criteria for AVN and Kalmachi and MacEwen's classification for growth disturbance. Non-parametric tests and Fisher exact test were used to compare enhancement values between AVN and non-AVN hips. Bonferroni correction was used for multiple comparisons.

RESULTS

Ten (21%) out of the 47 children (7 boys and 40 girls; mean age 9.0 ± 4.7 months) developed AVN. Age at surgical reduction was significantly higher (p = 0.03) for hips that developed AVN. No significant differences were found in gender (p = 0.61), laterality (p = 0.46), surgical approach (p = 0.08), history of pre-operative bracing (p = 0.72), abduction angle (p = 0.18-0.44), enhancement pattern (p = 0.66-0.76), or percent enhancement (p = 0.41-0.88) between AVN and non-AVN groups.

CONCLUSION

Neither enhancement pattern nor percent enhancement predicted AVN, suggesting that post-reduction conventional MRI does not accurately distinguish between reversible and permanent vascular injury.

Effect of age on radiographic outcomes of patients aged 6-24 months with developmental dysplasia of the hip treated by closed reduction

This study aimed to investigate the effect of age on the rates of redislocation, avascular necrosis (AVN) of the femoral head, and final radiographic outcomes in patients with developmental dysplasia of the hip (DDH) treated with closed reduction. A total of 308 hips (276 patients) with DDH treated with closed reduction were included and divided into three groups according to age (<12, 12-18, 18-24 months). Tönnis grade, rate of redislocation and AVN, Severin radiographic grade, and risk of surgery were evaluated on radiographs. Tönnis grade significantly increased with age (P < 0.001). Redislocation occurred in 17 (5.5%) and AVN occurred in 36 (11.7%) hips. The rate of redislocation and AVN was similar among the three age groups in all Tönnis grades. However, redislocation rate significantly increased with Tönnis grade (P = 0.027). Overall, 246 hips (79.9%) had satisfactory final outcomes, and 62 hips (20.1%) had unsatisfactory outcome; no difference was observed among three age groups. A total of 103 hips (33.4%) were found to be at risk for secondary surgery. The surgical risk (25%) in patients younger than 12 months was lower than that of older patients (12-18 months: 34.4%; 18-24 months: 37.9%). Logistic regression analysis also confirmed that age was not a risk factor for redislocation, AVN, or poor radiographic outcome. In conclusion, age has no significant impact on redislocation and AVN in patients aged 6-24 months with DDH treated by closed reduction. Although older patients have a higher risk developing residual acetabular dysplasia, secondary pelvic surgery provides favorable outcomes in most patients.

Radiographic outcome of children older than twenty-four months with developmental dysplasia of the hip treated by closed reduction and spica cast immobilization in human position: a review of fifty-one hips

PURPOSE

This study aimed to investigate the radiographic outcomes, rate of redislocation, and avascular necrosis of proximal femoral epiphysis (AVN) in patients aged 24 to 36 months with developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization in human position.

MATERIAL AND METHODS

We reviewed the medical records of 39 patients (51 hips) aged 24 to 36 months 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.

RESULTS

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.

CONCLUSIONS

Our study showed that stable CR could be achieved in 76.5% of patients aged 24 to 36 months 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.

Reduction by Pelvic External Fixator Followed by Innominate and Derotational Femoral Osteotomies for Late Presenting Bilateral Developmental Dysplasia of the Hip

Introduction

Bilateral developmental dysplasia of the hip is a challenging situation, closed and open reduction with or without pelvic and femoral osteotomies are all proposed.

Methods

We investigated the feasibility of closed ilizarov reduction combined with Salter and femoral osteotomy to provide stable concentric hips.

Results

We retrospectively reviewed 19 patients (38 hips). Tonnis Criteria, acetabular index and Center-edge angle were measured preoperatively and postoperatively. Acetabular index changed significantly (P<0,001), 80% were excellent or good according to Mckay, 25% were Ia and 69% were IIa Severin's criteria with at least three years follow-up.

Conclusion

The midterm overall results are favorable for application of this technique.

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.

Does Perfusion MRI After Closed Reduction of Developmental Dysplasia of the Hip Reduce the Incidence of Avascular Necrosis?

BACKGROUND

Gadolinium-enhanced perfusion MRI (pMRI) after closed reduction/spica casting for developmental dysplasia of the hip (DDH) has been suggested as a potential means to identify and avoid avascular necrosis (AVN). To date, however, no study has evaluated the effectiveness of pMRI in clinical practice or compared it with other approaches (such as postreduction CT scan) to show a difference in the proportion of AVN.

QUESTIONS/PURPOSES

(1) Can a pMRI-based protocol be used immediately post closed reduction to minimize the risk that AVN would develop? (2) What are the overall hip-related outcomes after closed reduction/spica casting using this protocol? (3) Do any patient-specific factors at the time of closed reduction predict future AVN?

METHODS

This was a retrospective cohort study at a large tertiary care children's hospital. Between 2009 and 2013 we treated 43 patients with closed reduction/spica casting for DDH, of whom 33 (77%) received a postreduction pMRI. All patients were indicated for pMRI per treating surgeon preference. A convenience sample totaling 25 hips in 22 patients treated with pMRI was then established using the following exclusion criteria: DDH of neuromuscular/syndromic origin, failed initial closed reduction, less than 1 year of clinical and radiographic followup, and subsequent open reduction. Next, the 40 patients treated with closed reduction between 2004 and 2009 were screened until the chronologically most recent 25 hips (after applying the previously mentioned exclusion criteria) were identified in 21 of the first 34 patients (62%) screened. Although termed the CT group, specific postreduction imaging was not a defined inclusion criterion in this group with the majority (21 of 25 [84%]) receiving postreduction CT and the remainder (four of 25 [16%]) receiving only postreduction radiographs. All hips with globally decreased femoral head perfusion on postreduction pMRI were treated with immediate cast removal followed by repeat closed reduction or open reduction, as per surgeon preference, with two of 33 (6%) requiring such further interventions. Salter criteria were then used to determine the proportion of AVN on radiographs at 1-year and final followup. Secondary outcomes including residual dysplasia and the need for further corrective surgery were ascertained through radiographic and retrospective chart review.

RESULTS

At 1-year followup there was no difference in the proportion of AVN in the historical CT group as compared with the pMRI group (six of 25 [24%] versus one of 25 [4%]; odds ratio [OR], 7.6; 95% confidence interval [CI], 0.8-363; p = 0.098). However, by final followup there was a statistically higher proportion of AVN in the CT group (seven of 25 [28%] versus one of 25 [4%]; OR, 9.3; 95% CI, 1.0-438; p = 0.049). No patient with normal perfusion on postreduction pMRI went on to develop AVN. In those pMRI patients in whom a successful reduction was initially obtained, two of 25 (8%) went on to require further corrective surgery and one of 25 (4%) had a redislocation event. With the numbers available, no patient-specific factors at the time of closed reduction were predictive of future AVN, including the patient's age/weight, the presence of an ossific nucleus, history of previous bracing treatment, or the abduction angle in spica cast.

CONCLUSIONS

A pMRI-based protocol immediately after closed reduction/spica casting may decrease the risk of AVN by helping the surgeon to evaluate femoral head vascularity. Although preliminary in nature, this study could serve to guide further investigation into the potential role of pMRI for the treatment of patients who require closed reduction/spica casting for DDH.

LEVEL OF EVIDENCE

Level III, therapeutic study.