Is Screening for Congenital Dislocation of the Hip Effective?
ABSTRACT & COMMENTARY
Synopsis: Universal clinical screening for hip dysplasia was mandated in the United Kingdom in 1969. The number of children subjected to surgery for congenital hip dysplasia was similar to that seen before universal screening was implemented. Current screening strategies do not detect 70% of neonates who subsequently require surgery.
Source: Godward S, Dezateux C. Surgery for congenital dislocation of the hip in the U.K. as a measure of outcome of screening. Lancet 1998;351:1149-1152.
Universal clinical screening for congenital dislocation of the hip to detect hip instability in neonates was introduced in the United Kingdom as a national policy in 1969. However, the effectiveness of this policy is not known. Godward and Dezateux on behalf of the Medical Research Council Working Party on Congenital Dislocation of the Hip established a national orthopedic surveillance scheme and used routine hospital data for inpatients for 20% of births in the United Kingdom. They ascertained the number of children younger than 5 years of age per 1000 live births who had received at least one operative procedure for congenital hip dysplasia from April 1993 to April 1994. The annual incidence of an operative procedure for hip dysplasia was found to be 0.78 per 1000 live births. Congenital hip dysplasia was not suspected by routine screening (the detection of hip instability) three times in the first six weeks of life. Seventy percent (222/318) of children who required surgical procedures had not been detected. Rather, they were usually diagnosed because of parental concern about gait after they began walking, at which time surgery is necessary. The estimated frequency of congenital dislocation of the hip in the United Kingdom before routine neonatal screening was 1-2 per 1000 live births. Godward and Dezateux conclude that the incidence of congenital hip dysplasia requiring surgery was similar to what was seen prior to the introduction of universal neonatal screening in 1969. They call for formal evaluation of current and alternative screening procedures including the possibility of universal primary ultrasound imaging.
COMMENT BY PETER A. DELUCA, MD
Godward and Dezateux unhappily, and possibly erroneously, conclude that the majority of children in their study (222 or 70%) who undergo surgery younger than the age of five have failed their program of universal clinical screening for neonatal hip instability. This program specifically calls for evaluations within 24 hours of birth, hospital discharge, and six weeks. Apparently, 96 (30%) of the 318 surgical cases were captured in this period. (We are not provided with the number that were successfully detected and treated non-operatively.) An additional 110 (35%) were, however, detected by examinations performed for the detection of hip dysplasia after the age of 3 months. Therefore, clinical examination was a successful detection tool for 65% of these children. Obviously, a total lack of clinical competence could conceivably lead to a much higher rate of surgeries than their 0.789 per 1000, if one considers that the incidence of hip instability is as high as one per 100. The signs of instability in the neonate, the Barlow and Ortolani, and the signs of limited abduction and shortening seen later, remain the principle tools of diagnosis.
It should be and is noted by Godward and Dezateux that much of the reported surgery is actually diagnostic and/or minimally invasive and may reflect progress in the overall management of congenital hip dislocation. These include arthrography, closed reduction, and spica casting, or adductor tenotomy. Together, these account for between 80-90% of the cases reported. These procedures have been more readily used to ensure that a perfect reduction of a dislocated hip is achieved and maintained. An understanding of the importance for perfect reduction has been emphasized since the mid 1980s, and this may certainly account for the number of "surgeries" reported in this study. Also, the low average age of surgery (11 months, range 6-18) is more consistent with the sophisticated use of minor or intermediate procedures in the treatment of the dislocated hip.
We should pay close attention to the importance of parental concerns as related to their child's hips. Thirty-five percent of the cases were diagnosed as a result of such worries. How often have we heard "the leg turns in," "the leg turns out," "she crawls funny," or "I feel a clunk?"
Godward and Dezateux do not report on the frequency of risk factors in their population. The examiner of the child's hip should pay close attention to family history of hip dysplasia, the dreaded first born breech female, the "molding" of stress conditions, such as metatarsus adductus and torticollis, and oligohydramnios. Such children warrant especially close attention, and possibly radiographic evaluation such as screening ultrasound at 1 month or radiograph after age 4 months. (Neonatal ultrasound does not seem to be as cost effective as screening of the high-risk child.)
The data in this study are not as negative, as Godward and Dezateux conclude. A well carried out examination of the hip from birth through the toddler years remains our strongest and most cost effective tool for the early detection and treatment of congenital dislocation of the hip. It will remain so only if training programs continue to teach the techniques and emphasize their importance. (Dr. DeLuca is Clinical Instructor of Orthopedics, specializing in Pediatric Orthopedics and Rehabilitation, Yale University School of Medicine.)