Peter J. Cundy

Perinatal risk factors for developmental dysplasia of the hip

AIMS To identify perinatal risk factors for developmental dysplasia of the hip (DDH) and define the risk for each factor. METHODS In this case control study, using logistic regression analysis, all 1127 cases of isolated DDH live born in South Australia in 1986-93 and notified to the South Australian Birth Defects Register were included; controls comprised 150 130 live births in South Australia during the same period without any notified congenital abnormalities. RESULTS Breech presentation, oligohydramnios, female sex and primiparity were confirmed as risk factors for DDH. Significant findings were an increased risk for vaginal delivery over caesarean section for breech presentation (as well as an increased risk for emergency section over elective section), high birthweight (⩾4000 g), postmaturity and older maternal age; multiple births and preterm births had a reduced risk. There was no increased risk for caesarean section in the absence of breech presentation. For breech presentation, the risk of DDH was estimated to be at least 2.7% for girls and 0.8% for boys; a combination of factors increased the risk. CONCLUSIONS It is suggested that the risk factors identified be used as indications for repeat screening at 6 weeks of age and whenever possible in infancy. Other indications are family history and associated abnormalities.

Synovial hemangioma of the knee.

Hemangioma of the knee is a cause of pain and recurrent hemarthroses in the pediatric age group, often seen as an internal derangement of the knee. Historically, long delays in diagnosis have occurred. Conventional radiographic techniques can miss the presence of the lesion. However, magnetic resonance imaging (MRI) is a noninvasive and frequently diagnostic investigative modality. Five cases of diffuse synovial hemangioma of the knee are presented. Diffuse lesions are difficult to excise arthroscopically, and open wide excision is recommended after MRI and arthroscopic assessment.

Late diagnosis of congenital dislocation of the hip and presence of a screening programme: South Australian population-based study

BACKGROUND The Medical Research Council Working Party on Congenital Dislocation of the Hip have reported an ascertainment-adjusted incidence of a first operative procedure for congenital dislocation of the hip (CDH) of 0.78 per 1000 livebirths, which is similar to the incidence of CDH before the start of the UK screening programme. The report showed that CDH had not been detected by routine screening before age 3 months in 70% of children reported to the national orthopaedic surveillance scheme. This report raised concerns about the merit of screening at birth for CDH. We aimed to find out the incidence of an operative procedure for CDH in the first 5 years of life among children born in South Australia between 1988 and 1993, and the proportion of these patients that were detected at age 3 months or older. METHODS The states database for inpatient separations between January, 1988, and April, 1998 was searched. Case records were examined for the age and circumstances of diagnosis, and type of operative procedures. Prevalence rates of CDH were obtained from the South Australian Birth Defects Register, which receives notifications from a statutory perinatal data collection of birth defects detected at birth and subsequent voluntary notifications for children up to age 5 years. FINDINGS Of the 55 children born in South Australia between 1988 and 1993 identified as having non-teratological CDH and operative procedures, only 22 (40%) had been diagnosed at age 3 months or older. 18 had an open reduction of the hip joint or osteotomy, or both, and the remainder had arthrograms, closed reductions, and/or tenotomy. The prevalence of non-teratological CDH in children was 7.74 per 1000 livebirths. The incidence of surgery for CDH in the first 5 years of life was 0.46 per 1000 livebirths (95% CI 0.34-0.59) and only 0.19 per 1000 livebirths (0.11-0.26) for those diagnosed late (age 3 months or older). These children diagnosed late represented 2.4% of all known cases of CDH. INTERPRETATION Only 2.4% of known cases of CDH in children born in South Australia had been detected late and required surgery. These results show that a screening programme for CDH can be successful, contrary to the findings of the UK Medical Research Council Working Party.

Skeletal age estimation in leg length discrepancy.

Sixty hand radiographs of children with known leg length discrepancy were reported independently in a “blind” manner by four radiologists using the Greulich and Pyle Atlas. Significant variation was found. Fifty percent of the children were assigned a skeletal age that differed by more than 1 year between radiologists; 10% varied by more than 2 years (p < 0.05). Female skeletal age was considerably understimated by an average of 11 months. Skeletal age estimation is one source of error in the timing of surgery for leg length equalization, especially when a single estimate is used. Skeletal age also appears to be more variable in children with leg length discrepancy.

Differences in risk factors between early and late diagnosed developmental dysplasia of the hip.

Background: Developmental dysplasia of the hip (DDH) is common, affecting 7.3 per 1000 births in South Australia. Clinical screening programmes exist to identify the condition early to gain the maximum benefit from early treatment. Although these screening programmes are effective, there are still cases that are missed. Previous research has highlighted key risk factors in the development of DDH. Objective: To compare the risk factors of cases of DDH identified late with those that were diagnosed early. Methods: A total of 1281 children with DDH born in 1988–1996 were identified from the South Australian Birth Defects Register. Hospital records of those who had surgery for DDH within 5 years of life were examined for diagnosis details. Twenty seven (2.1%) had been diagnosed at or after 3 months of age and were considered the late DDH cases (a prevalence of 0.15 per 1000 live births). Various factors were compared with early diagnosed DDH cases. Results: Female sex, vertex presentation, normal delivery, rural birth, and discharge from hospital less than 4 days after birth all significantly increased the risk of late diagnosis of DDH. Conclusions: The results show differences in the risk factors for early and late diagnosed DDH. Some known risk factors for DDH are in fact protective for late diagnosis. These results highlight the need for broad newborn population screening and continued vigilance and training in screening programmes.

Cotrel-Dubousset instrumentation and vertebral rotation in adolescent idiopathic scoliosis

We have studied 34 consecutive patients receiving Cotrel- Dubousset instrumentation for a single and flexible thoracic scoliotic curve, evaluating the rib hump deformity from a single CT scan through the apical vertebra of the curve. Using two measures of rotation we found a mean improvement of 25% in the rotation of the vertebra after operation. Any, usually minor, deterioration occurred in the first six months postoperatively, and there was no significant further deterioration in 19 patients assessed over two years after surgery. Cotrel-Dubousset instrumentation can produce a significant correction of vertebral rotation and of the associated rib hump deformity.

Developmental dysplasia of the hip in South Australia in 1991: prevalence and risk factors.

To determine the prevalence of developmental dysplasia of the hip (DDH) in South Australia (SA) in 1991, the proportion of cases detected in the neonatal period and the perinatal risk factors for DDH.

Zebra Lines of Pamidronate Therapy in Children

BACKGROUND Pamidronate therapy is increasingly used in children for the treatment of low bone mineral density and increased bone fragility resulting from a spectrum of conditions. The aim of the present study was to determine and describe the radiographic features associated with cyclical bisphosphonate therapy in the growing skeleton. METHODS A retrospective review of the radiographs of thirty-five children who had been managed with cyclical pamidronate was carried out. The physeal growth rates were estimated by measuring the band intervals on radiographs and the corresponding time intervals between the administered doses of pamidronate. RESULTS Metaphyseal bands, which we call zebra lines, were observed with band intervals that were dependent on the age of the patient, the rate of growth, and the dosing regimen. Epiphyseal and apophyseal bands were also observed in some patients. A distinction was made between Harris growth arrest lines and zebra lines. There was no evidence to suggest a deceleration in bone growth in children managed with pamidronate. CONCLUSIONS The term zebra lines is proposed as a descriptive term for the characteristic pattern of metaphyseal banding seen on the radiographs of children receiving cyclical bisphosphonate therapy.

Helmets for snow sports: prevalence, trends, predictors and attitudes to use

BACKGROUND Traumatic head injury is the leading cause of mortality and serious morbidity in snow sports and is increasing in incidence. Helmet use in snow sports can reduce the incidence of head injury by up to 60%. Mandatory helmet use is not legislated in most recreational settings for snow sports. This study aimed to quantify the prevalence and trends of helmet use by skiers and snowboarders as well as to investigate predictors of helmet use and reasons why they are worn. METHODS A cross-sectional study including observation of skiers and snowboarders allocated to adult and child groups (5,267 persons), retrospective review of ski patrol accident report forms recorded between 2003 and 2008 (3,984), and completion of specially designed questionnaires by randomly approached snow sport participants (1,029). RESULTS In 2008, 16% of adults and 67% of children wore helmets. Helmet use increased for adult and child participants between 2003 and 2008. Children, men, and snowboarders were significantly more likely to wear a helmet than their respective counterparts. Significant predictors of helmet use were level of experience, past major crash requiring medical assistance, snow sport lessons, and location of activity. Key reasons for helmet use and disuse were identified. DISCUSSION Child helmet use far exceeded adult helmet use. Rates of voluntary helmet use are increasing but many remain unprotected from the benefits of a helmet. Identification of the snow sport participants least likely to wear a helmet and their reasons for not doing so should allow targeted helmet promotion and injury prevention strategies to reduce serious head injuries in snow sports.

Syringomyelia in children with primary scoliosis

Abstract The clinical notes of 35 children presenting with scoliosis were reviewed; all 35 had been investigated with MRI. Seven were found to have syringomyelia, and six of these had Chiari malformation. Correction of the syrinx resulted in improvement or stabilisation of the spinal curvature. We recommend that all cases presenting with primary scoliosis should have MRI and should be treated if a syrinx is found.