Congenital dislocation of the hip in boys

Prognostic factors for failed Pavlik harness treatment in infants with developmental dysplasia of the hip: a retrospective cohort study

PURPOSE

Pavlik harness treatment is the most common treatment in newborns diagnosed with developmental dysplasia of the hip (DDH). The success rates and predictors for failure have been debated over the last decade. In this study, we explored our treatment failure rate and potential prognostic factors that could predict the failure of Pavlik harness (PH) treatment in patients with DDH.

METHODS

Two hundred and sixty-five patients were treated with PH based on the Graf hip types of classification. Age, gender, first born status, family history, foot deformity, plagiocephaly, breech presentation, hip abduction, hip stability, Graf hip type, Galeazzi sign, bilateralism, and femoral nerve palsy were tested as predictors for failure in multivariate logistic regression mode. Success and failure were determined by the normalization of the hip based on the Graf hip classification.

RESULTS

The failure rate of patients treated with Pavlik harness was 16.6% which is within the reported range of failure rate. The mean age of patients who were successfully treated was 6.73 weeks in comparison to 8.84 weeks for those who failed. Age, plagiocephaly, hip instability, Graf classification, and the development of femoral nerve palsy were found to be predictors for failure of PH treatment upon univariate analysis only. However, only the presence of Galeazzi sign, hip instability, high grades of Graf hip classification, and the development of femoral nerve palsy proved to be independent predictors for failed PH treatment upon multivariate logistic regression analysis.

CONCLUSIONS

Pavlik harness treatment is a successful treatment with an average success of 83.4%. Several independent predictors for failure of PH treatment have been identified. These include a positive Galeazzi sign, a frankly dislocated hip, Graf types III and IV, and the development of femoral nerve palsy.

Clinical and sonographic improvement of developmental dysplasia of the hip: analysis of 948 patients

BACKGROUND

Developmental dysplasia of the hip is a common condition, which varies in severity. Abduction treatment is widely used to correct the development of the hips, but mild forms of DDH can also recover spontaneously. The purpose of this study was to evaluate factors affecting the rate of improvement of developmental dysplasia of the hip, and evaluate any risk factors slowing the process.

MATERIAL AND METHODS

The study population consisted of patients diagnosed with DDH in Tampere University hospital in the years 1998-2018. Data were retrospectively collected, and associations between clinical variables and rate of improvement were analyzed. Alpha angles were assessed monthly, and associations between risk factors and improvement of alpha angles were studied. A total of 948 patients were included in the analysis.

RESULTS

More severe first status of the hips was associated with faster improvement in dynamic ultrasound compared to milder DDH in univariate design in first 3 months of age; in the multivariable design, Ortolani positivity was conversely associated with lower alpha angles in 1-month follow-up. Immediate abduction treatment was associated with faster recovery rate compared to delayed abduction or watchful waiting. Female sex and positive family history were associated with slower rate of improvement and lower alpha angles. In multivariable design, female sex, positive family history and treatment strategy remained statistically significant as initiation time of the treatment explained the first found association of clinical hip status and the recovery rate after 2 months of age.

CONCLUSION

Female sex and positive family history might be independent risk factors for slower recovery in DDH before 6 months of age. These children might need special attention in their follow-up plans and abduction treatment.

Can Medialization of Acetabular Rim Be a Prognostic Factor in Treatment of Developmental Dysplasia of Hip?

OBJECTIVES

To investigate if acetabular rim medialization (ARM) can be used as a new parameter in determining the treatment choice and duration in Graf type III and IV hips.

METHODS

Among the 12,300 infants who underwent hip ultrasound (US) according to Graf's method between 2015 and 2019, 26 infants (9 had bilateral pathology hence 35 hips) with type III and IV hips, whose follow-up data could be obtained were included in the study. Age of the infants at the initial diagnosis, ARM measurement, the duration of harness treatment, and the treatment results were noted. To determine the extent of ARM, distance between a line that is drawn tangential to the iliac wing and acetabular rim was measured.

RESULTS

In cases with poor prognosis, ARM measurement was 6 to 8.5 mm on the right hip and 4 to 9 mm on the left hip. Bilaterality or unilaterality, left or right pathology, and gender did not have a significant effect on the prognosis (P >.05). Age at the initial diagnosis and ARM had significant effects on treatment success (P = .04, P = .00, respectively). In predicting the prognosis, ARM was found to be more successful than age (AUC = 0.95 versus AUC = 0.68). When these two variables were evaluated together, the success in predicting the prognosis significantly increased (AUC = 0.98).

CONCLUSIONS

ARM measurement may have an important role in determining the treatment method and duration in Graf type III and IV hips. It can be used as a prognostic factor alone or in combination with treatment initiation time. When the two factors are combined, prognostic value significantly increases.

Clinical features and management of the developmental dysplasia of the hip in congenital muscular torticollis

PURPOSE

A consistent relationship between CMT and DDH has been established. However, whether the presence of CMT has effect on clinical outcomes of DDH remains unanswered. This study aimed to evaluate clinical features and management of DDH in patients with CMT.

METHODS

We reviewed the medical records of 54 patients (91 hips) simultaneously diagnosed with DDH and CMT and included 54 patients (97 hips) with only DDH by random number method as the control group. Clinical and examination outcomes were recorded and compared, respectively.

RESULTS

The mean follow-up was 18.1 ± 14.5 months (range, 2 to 72 mo). In the DDH and CMT group, the age of initial treatment was lower (100.8 ± 92.3 vs. 229.0 ± 157.4 d, P < 0.001), and the rate of male significantly increased (42.6% vs. 11.1%, P < 0.001). Before treatment, development degree of hip was better than that of the DDH group. Therefore, patients with CMT had approximately 14 times greater odds of conservative treatment success than children in the DDH group (OR, 13.84; 95% CI, 3.16 to 60.60).

CONCLUSION

We concluded that CMT was not the risk factor for the failure of treatment. On the contrary, the identification of CMT may be beneficial to early discovery and treatment of DDH when we remain vigilant to perform physical exam and screen imaging of DDH for patients with CMT.

The nomogram predicting the early failure rate of the Pavlik harness for developmental dysplasia of the hip in infants under 6 months of age

BACKGROUND

The aim of our study was to develop a nomogram predicting the early failure rate of Pavlik harness in infants under 6 months of age with developmental dysplasia of the hip (DDH).

METHODS

We retrospectively analyzed the clinical data of 227 patients (372 hips) with DDH who were treated with Pavlik harness at our institution from August 2019 to January 2022. Fifty-eight patients (102 hips) failed the Pavlik harness treatment, and 169 patients (270 hips) were successfully treated. Then, the independent risk factors for treatment failure were determined via univariate and multivariate logistic regression and used to generate the nomogram predicting the failure rate of the Pavlik harness.

RESULTS

It was found that age at initial treatment (OR 1.031, 95% CI 1.022-1.040, P < 0.001), angle α (OR 0.723, 95% CI 0.671-0.779, P < 0.001), and concomitant deformity (OR 0.129, 95% CI 0.036-0.459, p = 0.002) were independent risk factors for treatment failure. The nomogram showed good discrimination [the area under the curve (AUC): 0.862], good calibration, and a net benefit in the range of probabilities between 5 and 90% according to the decision curve analysis.

CONCLUSION

This study successfully established the nomogram prediction model based on three independent risk factors. Due to the high level of predicting accuracy, this nomogram could be a useful resource for pediatric orthopedic surgeons to identify patients at major risk of Pavlik harness failure who might need more reliable treatments.

Narrative Review of Complications Following DDH Treatment

BACKGROUND

The purpose of this narrative review was to survey the literature for common complications following treatment of DDH in children less than 4 years old.

METHODS

The Pubmed database was queried. Search result titles were reviewed to identify papers that were pertinent to the topic. Abstracts for these papers were obtained and read, and a subset of these were selected for review of the complete manuscript.

RESULTS

92 manuscripts were reviewed. Residual dysplasia, redislocation, and osteonecrosis are the primary complications of treatment in this age group. In the long term, hips without complications related to DDH treatment tend to do well, although a significant percentage of them will inevitably require joint replacement surgery.

CONCLUSION

Although there is excellent potential for a good outcome when DDH is diagnosed and treated under age 4 years, osteonecrosis continues to be a concern with all treatment methods. A subset of patients from this young cohort will continue to have residual dysplasia or recurrent dislocation requiring return to the operating room.

Risk Factors for Failure of Pavlik Harness Treatment in Infants With Dislocated Hips That Are Evaluated by Dynamic Sonography

BACKGROUND

Frankly dislocated hips occur in ∼1% to 3% of infants with developmental dysplasia of the hip and are often difficult to treat. In the most severely dislocated hips, the femoral head is positioned outside the posterior/lateral rim of the acetabulum and is irreducible, that is, the femoral head will not reduce by positioning the leg. The purpose of this study was to determine risk factors, using univariate and multivariate analyses, for Pavlik harness failure in infants who initially presented with irreducible/dislocated hips (confirmed by dynamic sonography).

METHODS

Following institutional review board approval, 124 infants (170 hips) with frankly dislocated hips treated using a Pavlik harness between 2000 and 2018 were evaluated. Patients' demographic characteristics, clinical findings, dynamic sonographic findings (dislocated-fixed vs. dislocated-mobile), age at onset of Pavlik harness treatment, duration of harness usage, and follow-up treatments were recorded. Univariate analyses were used to determine risk factors for treatment failure.

RESULTS

In frankly dislocated hips (confirmed by dynamic sonography to be positioned outside the posterior/lateral rim of the acetabulum), Pavlik harness treatment was successful in 104 of 170 hips (61%) while it failed in 66 hips. Mean follow-up was 4.86±4.20 years. Univariate analysis determined the risk factors to be onset of treatment after the seventh week of age (P=0.049) and initial mobility (dislocated-fixed group) (P<0.001) by dynamic sonography. In addition, multivariate analysis (P=0.007) showed infants of multigravida mothers (non-firstborn) to be another risk factor for failure. Six percent of hips with no risk factors failed Pavlik harness treatment, those with 1 risk factor had 42% failure, 2 risk factors had 69% failure, and all 3 risk factors had 100% failure.

CONCLUSIONS

In our patients with frankly dislocated irreducible hips, 39% of hip failed Pavlik harness treatment. Independent multivariate, logistic regression analysis, and multivariate analysis determining the risk factors for failure of Pavlik harness treatment were onset of treatment after the seventh week of age, infants of multigravida mothers, and initial hip mobility (fixed-dislocated hips) by dynamic sonography.

LEVEL OF EVIDENCE

Level III.

THE EPIDEMIOLOGY OF DEVELOPMENTAL DYSPLASIA OF THE HIP IN MALES

Developmental Dysplasia of the Hip (DDH) is one of the most common orthopedic hip diseases of the pediatric population. There is a predominance in females and patients with known risk factors.

Management of Irreducible Hip Dislocations in Infants With Developmental Dysplasia of the Hip Diagnosed Below 6 Months of Age

BACKGROUND

Infants with dislocated irreducible (D/I) hips can be substantially harder to treat than infants with dislocated but reducible hips. The purpose of this study was to compare treatment methods and outcomes for infants with D/I hips in order to optimize management of this difficult patient cohort.

METHODS

A multicenter prospective hip dysplasia study database was analyzed from 2010 to 2016. Infants aged below 6 months with clinically and radiologically confirmed D/I hips were included in the study. Teratological hips (syndromic/neuromuscular) were excluded.

RESULTS

In total, 59 hips in 52 patients were included. All hips were clinically Ortolani negative and radiologically dislocated but irreducible on presentation and had at least 20 months of follow-up. Mean age at diagnosis was 1.9 months (range, 0.1 to 5.9 mo). There were 33 left hips, 12 right hips, and 14 bilateral hips (7 patients). In total, 48 of 59 hips were treated in Pavlik harness. The remainder were treated by alternative braces or primary closed or open reductions. Pavlik treatment was successful in 27 of 48 hips. Pavlik treatment was abandoned in 21 D/I hips, 3 due to femoral nerve palsy and the remainder due to failure to achieve reduction. There was no statistical correlation between Pavlik success and age at diagnosis (P=0.22), patient sex (P=0.61), or bilateral compared with unilateral D/I hips (P=0.07). Left hips were more likely to be successfully reduced in Pavlik harness than right hips (P=0.01). Five complications occurred: 3 patients developed femoral nerve palsy in Pavlik harness, while 2 patients developed avascular necrosis, both after failed Pavlik treatment and subsequent surgery.

CONCLUSIONS

Pavlik harness treatment has been demonstrated to be a safe and sensible first-line treatment for infants with D/I hips. Left hips were more likely to be successfully reduced in Pavlik harness than right hips, but age, sex, and bilaterality were not correlated. The outcomes demonstrated from this multicentre prospective database inform management of this complex patient cohort.

LEVEL OF EVIDENCE

Level II-prognostic study: less-quality prospective study.

Treatment of developmental dysplasia of the hip with the Pavlik harness in children under six months of age: indications, results and failures

PURPOSE

The aim of this article is to review the current concepts in the indications, results and failure causes of the treatment of developmental dysplasia of the hip (DDH) with the Pavlik harness.

METHODS

The reported variables influencing the outcome in the Pavlik harness treatment were analyzed.

RESULTS

Significant discrepancies about the clinical and radiological outcomes, the rates of failure and complications as well as the variables influencing the treatment outcome occur in the published studies due to the heterogeneity of the data and the differences in the methods used. The overall short-, mid- or long-term success rate of the treatment ranges from 45% to 100% and it is commonly over 75%. The rate of osteonecrosis of the femoral head ranges from 1% to 30%. Age, gender, laterality, radiological or clinical severity of the initial hip pathology and parents' compliance are the commonly reported determinants of failure of the treatment.

CONCLUSION

The failure in treatment with the Pavlik harness is multifactorial, initial type of hip dysplasia being the most prominent followed by the treatment initiation age. This type of treatment cannot be considered as the best option in Graf IV hips (hip ultrasonography) or highly dislocated hips (plain radiography) and in infants older than three months of age, as the risk of failure and development of complications including osteonecrosis and femoral nerve palsy seem to increase in such circumstances. Large-scale, comparative studies including homogenous data are needed to answer the unsolved questions concerning indications.

Higher Pavlik Harness Treatment Failure Is Seen in Graf Type IV Ortolani-positive Hips in Males

BACKGROUND

Patients with developmental dysplasia of the hip (DDH) whose hips are dislocated but reducible (Ortolani positive) are more likely to experience Pavlik harness treatment failure than are patients with dysplastic and reduced but dislocatable (Barlow positive) hips. However, data regarding factors associated with failure are limited and conflicting.

QUESTIONS/PURPOSES

We asked: (1) What is the frequency of Pavlik harness treatment failure among Ortolani-positive hips, Barlow-positive hips, and dysplastic hips? (2) What are the factors predictive of failure of Pavlik harness treatment for Ortolani-positive hips?

METHODS

In this retrospective study we identified 150 patients who underwent the Pavlik harness method for treatment of DDH between August 2011 and July 2015. Six patients initially treated at an outside facility, four patients with associated conditions, and three who pursued treatment elsewhere were excluded. A total of 137 patients (215 hips) with a median age at the time of Pavlik placement of 30 days (range, 4-155 days) were included. Of the 215 hips, 78 (36.3%) were Ortolani positive, 60 (27.9%) were Barlow positive, and 77 (35.8%) were stable, with the diagnosis of dysplasia made on ultrasound. All patients were treated with the Pavlik harness method. The primary outcome was failure of the Pavlik harness to achieve and maintain concentric hip reduction assessed by examination and ultrasound. All patients were followed after completion of Pavlik treatment for a minimum of 2 months (mean, 3 months; range, 2-4 months). In addition, 90% (122 of 137) of the patients were followed for a minimum of 6 months. Patient-specific data including family history, breech versus cephalic presentation at birth, age, sex, laterality, and hip abduction were recorded. Ultrasound data at the time of diagnosis included Graf classification, alpha angle, and percentage of femoral head coverage.

RESULTS

The Pavlik harness method failed in 27% (21 of 78) of hips that were Ortolani positive, 8% (six of 77) with dysplasia, and 5% (three of 60) that were Barlow positive. After controlling for potential confounding variables, such as range of hip abduction, male sex (adjusted odds ratio [OR], 6.9; 95% CI, 2.0-24.2; p = 0.002) and Graf Type IV ultrasound classification (dislocated hip with alpha angle less than 43° and labrum displaced downward) (OR, 4.4; 95% CI, 1.3-15.4; p = 0.019) were identified as independent predictors of failure of Pavlik treatment among Ortolani-positive hips.

CONCLUSIONS

Ultrasound imaging of the hip should be part of the initial assessment for Ortolani-positive hips, as the ultrasound classification was found to have prognostic implications. Parents of male infants with Graf Type IV hips should be counseled regarding the higher risk of Pavlik failure. Future well-designed prospective controlled studies are necessary to establish whether alternative strategies to the Pavlik harness might improve the early outcomes of DDH in males with Graf Type IV hips.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Success of Pavlik Harness Treatment Decreases in Patients ≥ 4 Months and in Ultrasonographically Dislocated Hips in Developmental Dysplasia of the Hip

BACKGROUND

Treatment of developmental dysplasia of the hip (DDH) using the Pavlik harness has been a widely used method in patients between 0 and 6 months of age for many years. However, the factors influencing the success rate of this treatment modality have still not exactly been determined as a result of the limited number of clinical studies with higher level of evidence.

QUESTIONS/PURPOSES

We, therefore, asked whether (1) patient-related variables such as age, gender, and laterality; coexisting risk factors including family history, breech presentation, intrauterine packing, first-born girl, oligohydroamnios, and swaddling; and (2) the severity of hip dysplasia, defined by ultrasonography, are associated with differences in the success rate of Pavlik harness treatment in infants with DDH.

METHODS

Between 2012 and 2014, we treated 153 children (≤ 6 months of age) with DDH using the Pavlik harness. Hip dysplasia apart from coexisting neuromuscular disorders, congenital abnormalities, or syndromes was our inclusion criteria. Of patients thus treated, 130 (85%) were available for the evaluation of patient- and hip-related variables against the success of Pavlik harness treatment. Mean age of these patients on day of diagnosis and initiation of treatment was 108 days. The diagnostic and followup examinations of the hips were made by ultrasonography using Graf's method. Pavlik harness treatment was initiated in Graf Type IIa- and worse hips and treatment was considered "successful" when a Graf Type I hip was achieved. Pavlik harness treatment was successful in 92 (71%) patients (130 of 181 hips [72%]).

RESULTS

Age was the only patient-related variable influencing the success rate of the treatment; the mean age of children in whom Pavlik harness treatment succeeded (97 ± 38 days; 95% confidence interval [CI], 90-112) was lower than the age of those who failed (135 ± 37 days; 95% CI, 123-147; p < 0.001). The highest success rate was obtained in children younger than age 3 months (37 of 40 [93%]) and the lowest one older than age 5 months (nine of 24 [37%]) (p < 0.001). The threshold age value related to an increased risk of failure was found to be 4 months and older, which had a sensitivity of 66% and a specificity of 77% (p < 0.001). A higher initial α angle was observed in the hips in which the treatment succeeded (53° ± 6°; 95% CI, 51°-53°) than in those that failed (47° ± 7°; 95% CI, 45°-50°; p < 0.001). The threshold α angle value related to an increased risk of treatment failure was 46° and less, which had a sensitivity of 47% and a specificity of 86% (p < 0.001). Dislocated hips (Graf Type III and IV hips) had the lowest rate of treatment success (five of 19 [26%] and two of four [50%], respectively), whereas Graf Type IIa- hips had the highest (27 of 29 [93%]) (p < 0.001).

CONCLUSIONS

We conclude that Pavlik harness treatment is less effective in children at and over the age of 4 months at the time the harness is first applied as well as in hips with complete dislocations and hips with severely deficient acetabular bony roofs. In such older patients and worse hip types, the use of initial Pavlik harness treatment needs to be revisited. Future studies, comparing the outcomes of the Pavlik harness treatment and other types of interventions in such patients and hip types, are needed.

LEVEL OF EVIDENCE

Level III, therapeutic study.

High failure rate of the Pavlik harness in dislocated hips: is it bilaterality?

BACKGROUND

The purpose of this study was to evaluate the efficacy of Pavlik harness treatment in patients with bilaterally dislocated Graf type IV hips and compare them to cases with unilaterally dislocated hips.

METHODS

Twenty-one patients (42 hips) who presented with bilaterally dislocated hips with no prior treatment were studied. The comparison group consisted of 33 patients (33 hips) with unilateral hip dislocation treated with the same protocol. Successful treatment was defined as relocation of the hips within 3 weeks of Pavlik harness application.

RESULTS

Twelve of 21 patients (57%) in the bilateral group (6 failed bilaterally, 6 unilaterally) and 18/33 patients (54.5%) in the unilateral group failed harness treatment.

CONCLUSIONS

The use of the Pavlik harness in dislocated hips is associated with a high failure rate. Patients presenting with bilaterally dislocated hips however, are at no greater risk for failure than patients presenting with unilateral hip dislocation.

LEVEL OF EVIDENCE

Level III.

Inherited thrombophilia may be a causative factor for osteonecrosis of femoral head in male patients with developmental dysplasia of the hip: a case series

PURPOSE

The aim of this case series was to assess the effect of two common causes of inherited thrombophilia, factor V Leiden (FVL) and prothrombin mutation (PTM) on the development of osteonecrosis of the femoral head (ONFH) following the treatment of developmental dysplasia of the hip (DDH).

METHODS

FVL and PTM analysis of 58 patients (45 females and 13 males; mean age 12.2 years) with ONFH due to DDH treatment was done.

RESULTS

Rate of inherited thrombophilia (FVL plus PTM) was 15.5 %. Inherited thrombophilia was nearly four times higher in male patients than in female patients and this difference was mainly due to FVL (P < 0.05). This finding was against the common belief that, coagulation abnormalities were equally distributed across the sexes in normal population. Rates of overall inherited thrombophilia, FVL and PTM were not correlated with the type of ONFH (P > 0.05).

CONCLUSION

Hereditary thrombophilia, especially FVL, may be one of the causative factors for the development of ONFH following DDH treatment in male patients. Further prospective, controlled studies are needed to undoubtedly enlighten this issue.

Bilaterally dislocated hips treated with the Pavlik harness are not at a higher risk for failure

BACKGROUND

The purpose of this study is to evaluate the efficacy of the Pavlik harness treatment in patients with bilaterally dislocated hips, and to compare them with cases with unilaterally dislocated hips.

METHODS

Twenty-nine patients (58 hips) were identified who presented with bilateral dislocated hips with no earlier treatment and received dynamic ultrasound examination. The comparison group consisted of 38 patients (38 hips) with unilateral hip dislocation treated with the same protocol. Successful treatment was defined as relocation/reduction of the hips within 3 weeks of Pavlik harness application.

RESULTS

Seventeen of 29 patients (59%) in the bilateral group (7 bilateral, 10 unilateral) and 22 of 38 patients (58%) in the unilateral group failed the harness treatment. There was no difference in the duration of harness wear for successful patients regardless of presentation.

CONCLUSIONS

Patients presenting with bilaterally dislocated hips treated with the Pavlik harness are at no greater risk for failure than patients presenting with unilateral hip dislocation.

LEVEL OF EVIDENCE

Level 3.

Predictive factors for unsuccessful treatment of developmental dysplasia of the hip by the Pavlik harness

BACKGROUND

The Pavlik harness is a widely used and effective means of initial treatment of developmental dysplasia of the hip (DDH), but some hips fail to stabilize with the use of harness and avascular necrosis (AVN) of the femoral head can occur. Predictive factors for unsuccessful Pavlik harness treatment should be determined for appropriate indication of the treatment and prevention of AVN.

METHODS

The outcome of Pavlik harness treatment for DDH was retrospectively examined in 221 hips of 210 patients who were treated initially at our institution and followed up for at least 1 year after the application of the harness. Univariate analysis was performed to determine predictors for failure of reduction and for the incidence of AVN by using the Mann-Whitney U test for continuous variables and the Fisher exact test or the Pearson test for categorical variables. Next, independent multivariate predictors for the failure of reduction and the incidence of AVN were identified using logistic regression analysis.

RESULTS

One hundred and eighty-one hips were reduced and the overall rate of reduction was 81.9%. AVN that was diagnosed according to the criteria of Salter et al was identified in 16 of the 181 reduced hips and the rate of incidence of AVN was 8.8%. Bilaterality and decreased distance "a," as defined by Yamamuro and Chene, were statistically significant univariate and multivariate risk factors for the failure of reduction. Between them, distance a was the most powerful predictor. Adduction contracture of the hip (abduction with the hips flexed to 90 degrees <60 degrees) was the only significant univariate and multivariate predictor for the incidence of AVN.

CONCLUSIONS

Distance a and adduction contracture of the hip were important predictors for the outcome of Pavlik harness treatment. We concluded that the Pavlik harness is a very safe and effective means of DDH treatment for the hips with abduction > or = 60 degrees and distance a > or = 6 mm.

LEVEL OF EVIDENCE

Therapeutic studies, level III (retrospective study).

Dynamic gadolinium-enhanced MRI in early ischaemia of the proximal femoral epiphysis--a preliminary study

AIM

To compare the sensitivities of dynamic Gadoteridol (Gd)-enhanced magnetic resonance imaging (MRI) and conventional Gd-enhanced spin-echo (SE) T1-weighted imaging (WI) in the detection of decreased perfusion of early epiphyseal ischaemia, and to determine the contribution of metaphyseal vascularity to physeal perfusion in epiphyseal vascular occlusion by dynamic Gd-enhanced MRI.

MATERIALS AND METHODS

Twenty-eight 2-week-old piglets were divided evenly into four groups: control groups A and B, and ischaemic groups A and B (seven animals in each). In the ischaemic groups, MRI was performed bilaterally on hips in persistent hyperabduction for 30 min. In the control and ischaemic group A the piglets underwent dynamic Gd-enhanced MRI, and in control and ischaemic group B the piglets were subjected to Gd-enhanced SE T1WI.

RESULTS

In ischaemic group A, the enhancement ratio (ER) and enhancement speed (ES) of the various tissues (except the metaphysis) were significantly lower than those in control group A on dynamic Gd-enhanced MRI (p<0.05). However, in ischaemic group B, no significant decrease in the ER of each tissue was found, compared with the ER in control group B as viewed using Gd-enhanced SE T1WI (p>0.05). On dynamic Gd-enhanced MRI, the ER and ES of the physis were less than those of metaphysis in the ischaemic group A (p<0.05); however, the ER and ES of the physis were similar to those of metaphysis in control group A (p>0.05).

CONCLUSION

Dynamic Gd-enhanced MRI is more sensitive than conventional Gd-enhanced SE T1WI in the detection of early epiphyseal ischaemia. Physeal perfusion might be from the metaphysis in epiphyseal vascular occlusion.

Early reversible ischemia of femoral head epiphysis in piglets on gadolinium-enhanced MRI: an experimental study

The purpose of this study is to demonstrate if Gadolinium-enhanced MRI can detect early reversible ischemia of the femoral head epiphysis caused by hip hyper-abduction in piglets. Between 3 and 6 h consistent hyper-abduction, gadolinium-enhanced MRI was performed in 20 femoral heads of 10 piglets. After completion of MRI scan, the piglets were allowed to ambulate freely for 1 or 7 days and re-imaged. The enhanced-MRI results of epiphyseal and physeal cartilage and the secondary center of ossification were observed. MRI appearances and histological findings were compared. On Gadolinium-enhanced MRI, decreased or absent enhancement was seen in 14 cartilaginous epiphyses of all 20 femoral heads. Reperfusion was completed in 10 of 14 femoral heads after one day of ambulation and in the rest 4 after 7 days of ambulation. Gadolinium-enhanced MRI can identify early ischemia and its reversal of the capital femoral epiphysis induced by hip hyper-abduction.

Learning curves in orthopaedic surgery: a case for super-specialisation?

INTRODUCTION

The objective of this study was to assess if there is a significant learning curve in the treatment of developmental dysplasia of the hip.

PATIENTS AND METHODS

We followed up cases of developmental dysplasia of the hip treated by a single surgeon over a 12-year period. There were 96 cases, 56 treated by open reduction and 40 treated by closed reduction. Assessment was made of the incidence and degree of avascular necrosis in the treated hips, as a radiological outcome measure.

RESULTS

Plotting the cumulative percentage of satisfactory outcomes demonstrated an increasingly high percentage of satisfactory results with increasing number of procedures performed, i.e. as the surgeon progressed up the 'learning curve'.

CONCLUSIONS

This study demonstrates a learning curve in the treatment of developmental dysplasia of the hip. It may be possible to draw parallels to other treatments, and also support for the growing trend to specialisation.

The surgical treatment of established congenital dislocation of the hip: results of surgery after planned delayed intervention following the appearance of the capital femoral ossific nucleus

It has been proposed that the presence of the capital femoral ossific nucleus confers protection against ischemic injury or avascular necrosis (AVN) at the time of reduction of a congenitally dislocated hip. The current literature is contradictory. A prospective study was undertaken of the clinical and radiologic outcomes following closed or open reduction. Fifty hips were included in the study. These cases had presented late or had failed conservative treatment. In 28 hips treatment was intentionally delayed until the appearance of the ossific nucleus (but not beyond 13 months) and in 22 the ossific nucleus was present at clinical presentation. Six hips reached the age of 13 months without an ossific nucleus appearing and progressed to treatment. The significant AVN rate (more than grade 1) was 7% for closed reduction and 14% for open. However, the amended rate if hips were excluded that had failed Pavlik harness treatment was 0.0% and 9%, respectively (4% overall). Further surgical procedures were necessary in 57% of hips undergoing closed reduction and 41% after open, which compares favorably with other series. The authors conclude that the presence of the ossific nucleus is an important factor in the prevention of AVN, particularly after late closed reduction. Intentional delay in the timing of surgery does not condemn a hip to open surgery, but there is a comparable rate of secondary procedures becoming necessary, particularly after closed reduction. A simultaneous pelvic procedure may be appropriate after late closed reduction. The delayed strategy to await the appearance of the ossific nucleus for previously untreated dislocation allows a simple treatment algorithm to be employed that produces good clinical and radiologic outcomes.

Correlation of contrast-enhanced power Doppler sonography and conventional angiography of abduction-induced hip ischemia in piglets

OBJECTIVE

The purpose of this study was to determine if enhanced power Doppler sonography can detect early ischemia of the capital femoral epiphysis induced by hip hyperabduction in piglets and to correlate these findings with angiography.

MATERIALS AND METHODS

Proximal femoral perfusion was evaluated in 18 studies of 10 piglet hips with unenhanced power Doppler sonography, enhanced power Doppler sonography with IV contrast agent, and digital angiography, in neutral position, hyperabduction, and after release to neutral position. Enhancement ratios between pixel intensities of power Doppler sonography and enhanced power Doppler images in each position were calculated. Angiograms were analyzed for differences in flow with changes in hip position.

RESULTS

With the piglet in neutral position, power Doppler sonography revealed few vessels in the femoral head. Contrast administration resulted in a temporary marked increase in the visualization of vessels in the femoral head. Quantitative enhanced power Doppler sonography revealed a marked decrease in pixel intensity with abduction (p < 0.001) that was not apparent on unenhanced studies (p = 0.28). The enhancement ratio decreased from 0.45 (mean +/- SD, +/- 0.26) in neutral position to 0.10 (+/- 0.21) after abduction; it returned to 0.41 (+/- 0.14) after release of abduction (p < 0.001 for each comparison). Angiographic studies in hyperabduction revealed a variable level of ischemia.

CONCLUSION

Enhanced power Doppler sonography can be used to visualize the vascular supply to the cartilaginous femoral head in piglets and can detect reversible ischemia induced by hip hyperabduction. These differences correlate with digital angiographic evidence of ischemia.

Evaluation of the risk factors of avascular necrosis of the femoral head in developmental dysplasia of the hip in infants younger than 18 months of age

Sixty-seven dysplastic hips of 54 infants with an average age of 11.9 months were treated by the same surgical technique, including iliopsoas and adductor tenotomies via medial approach and arthrography for verification of the concentric reduction. The average follow-up period was 44.5 months. The rate of overall avascular necrosis (AVN) was 27% and that of severe AVN was 7%. With the numbers available in the study, a statistically significant relationship could not be found between the rate and severity of AVN and several preoperative and intraoperative components such as age, sex, side, dislocation grade, development of the ossific nucleus and qualitv of intraoperative reduction. Nevertheless, hips of infants treated between 13 months and 15 months of age, hips of male patients and left hips had slightly higher ratios of ischemic changes that were not statistically significant.

Early failure of Pavlik harness treatment for developmental hip dysplasia: clinical and ultrasound predictors

A cohort of 93 patients with developmental dysplasia of the hip (DDH) treated with a Pavlik harness were evaluated to determine predictors of treatment failure. Failure was defined as failure to achieve or maintain hip reduction in the Pavlik harness. Of 93 patients (137 hips), 17 (26 hips) failed Pavlik harness treatment. Univariate risk factors for failure included bilaterality, initial clinical exam, and initial ultrasound (US) percent coverage. Clinical exam and initial percent coverage were multivariate risk factors for failure. Among initially clinically dislocatable hips, a low initial US alpha angle correlated with an increased likelihood of failure. All (6/6) patients with an initially irreducible hip and an initial coverage of <20% by US eventually failed treatment. Gender, side of pathology, and age at diagnosis and initiation of treatment did not correlate with failure. Irreducibility by physical exam combined with US coverage of <20% identified a patient group that uniformly failed Pavlik harness treatment. These patients may be candidates for alternative bracing, traction, or closed or open reduction.

Early failure of Pavlik harness treatment for developmental hip dysplasia: clinical and ultrasound predictors

A cohort of 93 patients with developmental dysplasia of the hip (DDH) treated with a Pavlik harness were evaluated to determine predictors of treatment failure. Failure was defined as failure to achieve or maintain hip reduction in the Pavlik harness. Of 93 patients (137 hips), 17 (26 hips) failed Pavlik harness treatment. Univariate risk factors for failure included bilaterality, initial clinical exam, and initial ultrasound (US) percent coverage. Clinical exam and initial percent coverage were multivariate risk factors for failure. Among initially clinically dislocatable hips, a low initial US alpha angle correlated with an increased likelihood of failure. All (6/6) patients with an initially irreducible hip and an initial coverage of <20% by US eventually failed treatment. Gender, side of pathology, and age at diagnosis and initiation of treatment did not correlate with failure. Irreducibility by physical exam combined with US coverage of <20% identified a patient group that uniformly failed Pavlik harness treatment. These patients may be candidates for alternative bracing, traction, or closed or open reduction.

Development dysplasia of the hip from birth to six months

The term "developmental dysplasia or dislocation of the hip" (DDH) refers to the complete spectrum of abnormalities involving the growing hip, with varied expression from dysplasia to subluxation to dislocation of the hip joint. Unlike the term "congenital dysplasia or dislocation of the hip," DDH is not restricted to congenital problems but also includes developmental problems of the hip. It is important to diagnose these conditions early to improve the results of treat- ment, decrease the risk of complications, and favorably alter the natural history. Careful history taking and physical examination in conjunction with advances in imaging techniques, such as ultrasonography, have increased the ability to diagnose and manage DDH. Use of the Pavlik harness has become the mainstay of initial treatment for the infant who has not yet begun to stand. If stable reduction cannot be obtained after 2 weeks of treatment with the Pavlik harness, alternative treatment, such as examination of the hip under general anesthesia with possible closed reduction, is indicated. If concentric reduction of the hip cannot be obtained, surgical reduction of the dislocated hip is the next step. Toward the end of the first year of life, the toddlerTs ability to stand and bear weight on the lower extremities, as well as the progressive adaptations and soft- tissue contractures associated with the dislocated hip, preclude use of the Pavlik harness.

Legg-Calvé-Perthes disease in girls. A comparison of the results with those seen in boys

We reviewed the records and roentgenograms of all patients with Legg-Calvé-Perthes disease who had been seen at our institution between 1940 and 1996. One hundred and five girls (122 hips) and 470 boys (531 hips) were identified. Thus, 18 per cent of the 575 patients in the present series were girls. Seventeen (16 per cent) of the girls and sixty-one (13 per cent) of the boys had bilateral involvement. Although more girls than boys had severe involvement of the femoral head and the lateral pillar, we could not detect a significant difference between the two groups with respect to the distribution of the involvement of the hips according to the system of Catterall or the lateral pillar classification (p > 0.05, beta = 0.99). Serial roentgenograms that showed all four stages of the disease according to the system of Waldenström were available for fifty-two hips in girls and 184 hips in boys. A review of these roentgenograms revealed that the average ages of the girls at the stages of necrosis, fragmentation, reossification, and remodeling were 6.8, 7.3, 7.9, and 9.5 years, respectively, whereas the average ages of the boys were 6.8, 7.3, 7.9, and 9.9 years, respectively. Girls, however, had closure of the affected proximal femoral physis at an average age of 12.9 years, whereas boys had closure at an average age of 15.8 years. Therefore, girls had a shorter potential period for remodeling of the femoral head (average, 3.4 years) compared with boys (average, 5.9 years). Sixty-four girls (seventy-eight hips) and 363 boys (416 hips) had reached skeletal maturity by the time of the latest follow-up and were evaluated according to the system of Stulberg et al.; we could not detect a significant difference between boys and girls with respect to the distribution of the hips according to this system (p > 0.05, beta = 0.99). Although the numbers were too small for statistical analysis, our findings suggest that boys and girls who have the same Catterall or lateral pillar classification at the time of the initial evaluation can be expected to have similar outcomes according to the classification system of Stulberg et al.

Gadolinium-enhanced MR imaging demonstrates abduction-caused hip ischemia and its reversal in piglets

Purpose. To determine whether gadolinium-enhanced MR imaging can detect early reversible ischemia of the capital femoral epiphysis and physis induced by hip hyperabduction in piglets. Materials and methods. Thirteen 1- to 3-week-old piglets were placed in maximal abduction of both hips and studied with dynamic gadolinium-enhanced MR imaging 1-6 h later to assess ischemia of the 26 femoral heads. They were then allowed to ambulate freely for 1 or 7 days, and reimaged in neutral position to assess reperfusion. Enhancement was evaluated on MR images and compared with histologic findings.Results. Ischemia after hyperabduction developed in all 26 cartilaginous epiphyses and in 85 % of the physes. The most frequent abnormality was a sharply marginated nonenhancing area in the anterior part of the femoral head. A smaller area of ischemia developed in the posterior part of the femoral head, adjacent to the acetabular rim. The secondary center of ossification was ischemic in 56 % of the hips after 1 h of abduction and in all hips after 4 or 6 h (p = 0.02). The overall severity of ischemia was greater with increasing abduction time (p < 0.001) and increasing degree of abduction (p < 0.01). There was partial reperfusion in 83 % of the hips after 1 day of ambulation and complete reperfusion in all 26 hips (100 %) after 1 week.Conclusion. Enhanced MRI detects early ischemia of the epiphyseal and physeal cartilage and the epiphyseal marrow. In piglets, ischemia due to hyperabduction is reversible if corrected within 6 h.