Statistical Shape Modeling of US Images to Predict Hip Dysplasia Development in Infants.

Background The current widely applied Graf classification used on US images for developmental dysplasia of the hip in infants does not enable prediction of the development and outcome of well-centered stable dysplastic hips (Graf type II). Purpose To use statistical shape modeling on US images to identify acetabular shape characteristics of Graf type II hips, which enable prediction of the development of Graf type II hips, and to identify which hips benefit from Pavlik harness treatment. Materials and Methods In this secondary analysis of a prospective multicenter randomized trial on treatment of 104 infants aged 3-4 months with Graf type IIb or IIc hip dysplasia conducted between 2009 and 2015, a statistical shape model was developed on baseline US images. With multivariable logistic regression adjusted for infant sex and treatment (Pavlik harness treatment vs active observation), shape modes were correlated with the outcomes of persistent hip dysplasia on US images (α angle <60°) after 12-week follow-up and residual hip dysplasia on pelvic radiographs (Tönnis classification: acetabular index greater than 2 standard deviations) around 1 year of age. An interaction term (treatment with mode) was used to investigate if this result depended on treatment. Results Baseline US images were available in 97 infants (mean age, 3.37 years ± 0.43 [standard deviation]; 89 [92%] girls; 90 cases of Graf type IIb hip dysplasia; 52 cases treated with Pavlik harness). Shape modes 2 and 3 of the statistical shape modeling were associated with persistent hip dysplasia on US images (odds ratio [OR] = 0.43; P = .007 and OR = 2.39; P = .02, respectively). Mode 2 was also associated with residual hip dysplasia on pelvic radiographs (OR = 0.09; P = .002). The interaction term remained significant after multivariable analysis, indicating that Pavlik harness treatment was beneficial in patients with negative mode 2 values (OR = 12.46; P = .01). Conclusion Statistical shape modeling of US images of infants with Graf type II dysplastic hips predicted which hips developed to normal or remained dysplastic and identified hips that benefited from Pavlik harness treatment. © RSNA, 2022.

Morphological variants to predict outcome of avascular necrosis in developmental dysplasia of the hip.

AIMS: The most important complication of treatment of developmental dysplasia of the hip (DDH) is avascular necrosis (AVN) of the femoral head, which can result in proximal femoral growth disturbances leading to pain, dysfunction, and eventually to early onset osteoarthritis. In this study, we aimed to identify morphological variants in hip joint development that are predictive of a poor outcome. METHODS: We retrospectively reviewed all patients who developed AVN after DDH treatment, either by closed and/or open reduction, at a single institution between 1984 and 2007 with a minimal follow-up of eight years. Standard pelvis radiographs obtained at ages one, two, three, five, and eight years, and at latest follow-up were retrieved. The Bucholz-Ogden classification was used to determine the type of AVN on all radiographs. Poor outcome was defined by Severin classification grade 3 or above on the latest follow-up radiographs and/or the need for secondary surgery. With statistical shape modelling, we identified the different shape variants of the hip at each age. Logistic regression analysis was used to associate the different modes or shape variants with poor outcome. RESULTS: In all, 135 patients with AVN were identified, with a minimum of eight years of follow-up. Mean age at time of surgery was 7.0 months (SD 0.45), and mean follow-up was 13.3 years (SD 3.7). Overall, 46% had AVN type 1 while 54% type 2 or higher. More than half of the patients (52.6%) had a poor outcome. We found 11 shape variants that were significantly associated with a poor outcome. These shape variants were predominantly linked to AVN type 2 or higher. CONCLUSION: Specific morphological characteristics on pelvis radiographs of AVN hips were predictive for poor outcome, at a very young age. There was an overall stronger association to Bucholz-Ogden types 2-3-4 with the exception of two modes at age two and five years, linked to AVN type 1. Cite this article: Bone Joint J 2021;103-B(5):999-1004.

The Dutch version of the Oxford Ankle and Foot Questionnaire for Children: Useful for evaluation of pediatric foot problems in groups.

BACKGROUND: The purpose of this study is to develop a Dutch version of the Oxford Ankle and Foot Questionnaire for Children (OxAFQ-c) to allow evaluation of pediatric foot care. METHODS: The OxAFQ-c was translated into Dutch, according to the ISPOR-guidelines. Children with different foot and ankle complaints completed the OxAFQ-c at baseline, after two weeks, and after 4-6 months. Measurement properties were assessed in terms of reliability, responsiveness, and construct validity. RESULTS: Test-retest reliability showed moderate intraclass correlation coefficients. Bland-Altman plots showed wide limits of agreement. After 4-6 months, the group that experienced improvement also showed improved questionnaire outcomes, indicating responsiveness. Moderate correlation between the OxAFQ-c and the Kidscreen and foot-specific VAS-scores were observed, indicating moderate construct validity. CONCLUSIONS: The Dutch OxAFQ-c showed moderate to good measurement properties. However, because we observed limited sensitivity to changes and wide limits of agreement in individual patients, we think the questionnaire should only be used in groups.

A long term follow-up study of the development of hip disease in Mucopolysaccharidosis type VI.

Hip problems in Mucopolysaccharidosis type VI (MPS VI) lead to severe disability. Lack of data on the course of hip disease in MPS VI make decisions regarding necessity, timing and type of surgical intervention difficult. We therefore studied the development of hip pathology in MPS VI patients over time. Data were collected as part of a prospective follow-up study. Standardized supine AP pelvis and frog leg lateral radiographs of both hips were performed yearly or every 2years. Image assessment was performed quantitatively (angle measurements) and qualitatively (hip morphology). Clinical burden of hip disease was evaluated by physical examination, six minute walking test (6MWT) and a questionnaire assessing pain, wheelchair-dependency and walking distance. A total of 157 pelvic radiographs of 14 ERT treated MPS VI patients were evaluated. Age at first image ranged from 2.0 to 21.1years. Median follow up duration was 6.8years. In all patients, even in the youngest, the acetabulum and os ilium were dysplastic. Coverage of the femoral head by the acetabulum improved over time, but remained insufficient. While the femoral head appeared normal in the radiographs at young age, the ossification pattern became abnormal in all patients over time. In all patients the distance covered in the 6MWT was reduced (median Z scores -3.3). Twelve patients had a waddling gait. Four patients were partially wheelchair-dependent and ten patients had limitations in their maximum walking distance. In conclusion, clinically significant hip abnormalities develop in all MPS VI patients from very early in life, starting with deformities of the os ilium and acetabulum. Femoral head abnormalities occur later, most likely due to altered mechanical forces in combination with epiphyseal abnormalities due to glycosaminoglycan storage. The final shape and angle of the femoral head differs significantly between individual MPS VI patients and is difficult to predict.

Relative Risk and Incidence for Developmental Dysplasia of the Hip.

OBJECTIVE: To determine the incidence and associated risk factors of developmental dysplasia of the hip (DDH) in a modern population without universal screening. STUDY DESIGN: Children with DDH were identified from the Manitoba Centre for Health Policy's Data Repository by the use of International Classification of Diseases diagnosis codes as well as physician billing tariffs for surgical procedures for DDH for all children born between 1995 and 2012. To identify the outpatient-treated patients, ultrasound scans and radiographic imaging for DDH were reviewed for 2004-2012. Overall incidence was calculated on the basis of birth rate for the province per year. Relative risks of sex, first born, breech position, clubfoot deformity, multiple gestations, as well as regional health areas were analyzed with χ2 tests. RESULTS: We identified 1716 cases of DDH of 258 499 newborns. The incidence of DDH was calculated at 6.6/1000 newborns. Late-presenting DDH was detected in 2.2/1000 newborns. Female first-born children, clubfoot deformity, and breech position were associated significantly with an increased risk. Children with DDH born in rural areas of the Northern and Central part of Manitoba presented at a later age than those who are born in the urban areas (P < .0001) CONCLUSION: This study shows the need for improved early detection and awareness at well-baby clinics of risk factors and regional differences for DDH.

Results of Pavlik harness treatment in children with dislocated hips between the age of six and twenty-four months.

BACKGROUND: We retrospectively studied the outcome of Pavlik harness treatment in late-diagnosed hip dislocation in infants between 6 and 24 months of age (Graf type 3 and 4 or dislocated hips on radiographs) treated in our hospital between 1984 and 2004. The Pavlik harness was progressively applied to improve both flexion and abduction of the dislocated hip. In case of persistent adduction contracture, an abduction splint was added temporarily to improve the abduction. METHODS: We included 24 patients (26 hips) between 6 and 24 months of age who presented with a dislocated hip and primarily treated by Pavlik harness in our hospital between 1984 and 2004. The mean age at diagnosis was 9 months (range 6 to 23 mo). The average follow-up was 6 years 6 months (2 to 12 y). Ultrasound images and radiographs were assessed at the time of diagnosis, one year after reposition and at last follow-up. RESULTS: Twelve of the twenty-six hips (46%) were successfully reduced with Pavlik harness after an average treatment of 14 weeks (4 to 28 wk). One patient (9%) needed a secondary procedure 1 year 9 months after reposition because of residual dysplasia (Pelvis osteotomy). Seventeen of the 26 hips were primary diagnosed by Ultrasound according to the Graf classification. Ten had a Graf type 3 hip and 7 hips were classified as Graf type 4. The success rate was 60% for the type 3 hips and 0% for the type 4 hips. (P=0.035). None of the hips that were reduced with the Pavlik harness developed an avascular necrosis (AVN). Of the hips that failed the Pavlik harness treatment, three hips showed signs of AVN, 1 after closed reposition and 2 after open reposition. CONCLUSION: The use of a Pavlik harness in the late-diagnosed hip dislocation type Graf 3 can be a successful treatment option in the older infant. We have noticed few complications in these patients maybe due to progressive and gentle increase of abduction and flexion, with or without temporary use of an abduction splint. The treatment should be abandoned if the hips are not reduced after 6 weeks. None of the Graf 4 hips could be reduced successfully by Pavlik harness. This was significantly different from the success rate for the Graf type 3 hips. LEVEL OF EVIDENCE: Therapeutic study, clinical case series: Level IV.