2 JOURNAL OF SMALL ANIMAL PRACTICE • VOL 43 • JANUARY 2002 INTRODUCTION T he ventrodorsal (VD) view with extended hindlimbs, introduced in the 1960s (Riser 1962), is the most commonly used technique for the assessment of the canine hip joint according to the Fédéra- tion Cynologique Internationale (FCI), the Orthopaedic Foundation for Animals (OFA) and the British Veterinary Associa- tion/Kennel Club. More recently, different procedures have been proposed for the evaluation of articular laxity (Belkoff and others 1989, Smith and others 1990, Farese and others 1998, Fluckiger and oth- ers 1999), the likely precursor of radio- graphic signs of degenerative joint disease in canine hip dysplasia (CHD) (Smith and others 1990, Madsen and others 1994, Lust 1997). T hese approaches, while quite helpful in the early detection of disease and breeding selection, have a more limited impact on the treatment of CHD, since specific therapeutic procedures for articu- lar laxity have not been developed so far. T he conventional VD view can be used as a reference for surgical treatment planning (Schrader 1986, Prieur 1987). However, the dorsal portion of the acetabulum, the area believed to receive the highest mechan- ical stress, both in the standing position and in motion (Weigel and Wasserman 1992), cannot be directly evaluated in this view. In 1990, Slocum and Devine intro- duced the dorsal acetabular rim (DAR) view for the assessment of the dorsal por- tion of the acetabulum and of the femoral neck – crucial anatomical landmarks for pelvic osteotomy (Slocum and Devine 1992). According to those authors, the required degree of pelvic rotation could be based on a combined measurement of the acetabular slope (AS) angle in the DAR view, and of the angle of reduction of the femoral heads, during the Ortolani manoeuvre (Slocum and Devine 1992). However, the current authors’ first impression with using the above technique was that measurement of the AS angle was prone to frequent inter-observer disagree- ment. Based on a retrospective analysis of both the veterinary and human literature, it was therefore decided to compare the acetabular coverage measured by the centre-edge (CE) angle (Wiberg and Lund 1953) and the AS angle in a prospective study of D AR views. Over a period of 24 months, the authors routinely obtained both the DAR and the conventional VD view in a series of 106 dogs of large and giant breeds. T he purposes of the study were therefore:  To test the potential value of the CE angle in comparison with the AS angle for assessment of DAR coverage in the D AR view; PAPERS L. MEOMARTINO, G. F ATONE, A. POTENA AND A. BRUNETTI Journal of Small Animal Practice (2002) 43 , 2–6 The dorsal acetabular rim (DAR) view of the hip joint can be used to assess the weightbearing portion of the acetabulum and the acetabular coverage, providing an adjunct to the conventional ventrodorsal (VD) view in the radiographic evaluation of hip dysplasia in the dog. A quantitative index of acetabular coverage in the DAR view, the acetabular slope (AS) angle, was originally proposed in 1990. The aim of the present study was to make a prospective, comparative assessment of a new parameter, the centre-edge (CE) angle, with the AS angle, for the evaluation of the acetabular coverage of the femoral head in the DAR view. The reliability and repeatability of the two parameters was assessed using the r I value of intraclass correlation coefficient (ICC) in a prospective study of 208 hip joints in large and giant breed dogs. An estimation of the added value of using the DAR view, compared with that of the VD standard view alone, was also assessed. The CE angle showed a higher r I value compared with the AS angle; in 26 per cent of hips of FCI classes A, B and C, the DAR view provided additional diagnostic information compared with the VD view, with respect to lateralisation and/ or initial changes to the dorsal rim. It is concluded that the CE angle is more reliable than the AS angle in the evaluation of acetabular coverage, and that the DAR view provides valuable data compared with the VD view alone in the early stages of canine hip dysplasia. Morphometric assessment of the canine hip joint using the dorsal acetabular rim view and the centre-edge angle Centro di Radiologia Veterinaria, Dipartimento di Scienze Cliniche Veterinarie, Facoltà di Medicina Veterinaria, Università degli Studi di Napoli ‘Federico II’, Via F. Delpino 1, I-80137 Napoli, Italy