US hip dysplasia

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Article about real time US in hip dysplasia evaluation

Text of US hip dysplasia

  • 1. REAL-TIME ULTRASOUND IN THE DIAGNOSIS OF CONGENITAL DISLOCATION AND DYSPLASIA OF THE HIP N. M. P. CLARKE. H. THEODORE HARCKE, PETER McHUGH, MYUNG 500 LEE, PATRICIA F. BORNS, G. DEAN MAcEWEN From the Alfred I. duPont Institute, Wilmington, Delaware A technique of examining the infant hip joint with real-time ulfrasound is described. Since the cartilaginous femoral head is clearly imaged by ultrasound, anatomical structures and their relationships can be accurately determined. Dislocated hips are easily detected and subluxations also can be visualised. We report our experience with 131 examinations in 104 patients, comprising 259 single hip studies. Of 83 patients who were previously untreated, there were 178 hip studies with three false-negative and four false- positive ulfrasound results. No dislocations were missed. Twenty-seven patients who were already being treated were examined to assess hip location, comprising a total of 81 hip studies. In some cases the patients were examined while in an abduction device, cast, or Pavlik harness. In one case a disloction was not detected. The method of examination using real-time ultrasound is considered to be reliable, accurate, and a useful adjunct to radiography. The advantages are that it is non-invasive, portable, and involves no exposure to radiation.The diagnosis of instability and dysplasia in the hip of definitely abnormal. At present, clinical and radio-the newborn infant remains difficult. Although clinical graphic examinations are used to complement eachexamination is recognised as an effective screening other. A single examination by itself may be unsatis-method for dislocations, there remains a small popula- factory, and invasive arthrography may, in sometion of neonates in whom a confirmatory image is patients, be the only means of obtaining a clear imagedesirable. Radiographs are, of course, helpful in the of the developing hip joint.assessment of unstable hips (Bertol, Macnicol and Since Kleinberg and Lieberman (1936) introducedMitchell 1982) or frankly dislocated hips. However, the the acetabular index as a possible means of identifyingexact indications for and limitations of radiographic abnormal hips, confusion and controversy have existedexamination of the neonatal hip are still unclear. Un- and many attempts to clarify the exact radiographiccertainties arise in the interpretation of radiographs of indices for dysplasia have been made (Caffey et a!. 1956;the immature pelvis, regardless of the intended position Laurenson 1959). In some methods of evaluation,of the hip; indeed, position may be an important cause of complicated calculations are required (Tonnis I 976;simulated abnormality (Blank 1981). Wientroub 1981). Misinterpretation arises because the only structures In the context of this diagnostic dilemma, ultra-imaged by radiographs are the ossified portions of the sound has obvious potential for examining the infantpelvis. It therefore becomes necessary to extrapolate the hip. It requires no exposure to radiation and clearlyimage of the cartilaginous structures. Clearly this has images the cartilaginous structures that are so poorlydisadvantages, and a radiograph only contributes signifi- delineated by radiography.cantly to the diagnosis and management ofthe hip ifit is Graf(1983) was the first to realise this potential. He used a fixed-arm B-scanning unit to obtain sonographic images ofinfant hipjoints. His technique was necessarily complicated because of the equipment he used, and itN. M. P. Clarke, FRCS. Senior Registrar took considerable expertise and time to obtain a satis-Royal Orthopaedic Hospital, Woodlands, Northfield, Birmingham factory examination. Real-time ultrasound is muchB3l 2AP, England.H. T. Harcke. MD, Director, Department of Medical Imaging simpler to operate and is portable, and the ultrasoundP. McHugh, Research Student image changes rapidly enough to portray movement.M. S. Lee, MD, Radiologist. Department of Medical Imagingp. F. Borns, MD, Radiologist, Department of Medical Imaging Images are obtained by placing a transducer on the skinG. D. MacEwen, MD, Medical Director and scanning a specific sector of the anatomy. The sectorA