Repair of acetabular fractures in 20 dogs using a dorsal muscle separation approach

FRACTURES of the acetabulum account for 29 per cent of pelvic fractures (Wheaton and others 1973) and can involve the cranial, middle or caudal regions; conservative treatment can be an option for the latter site (Boudrieau and Kleine 1988, Butterworth and others 1994). The acetabulum can be approached surgically via osteotomy of the greater trochanter or gluteal tenotomy (Piermattei and Greeley 1979), osteotomy of the ischial tuberosity (Chalman and Layton 1990) or muscle separation (Wadsworth and Henry 1974). Repair of acetabular fractures can be achieved by the use of plates (Robins and others 1973, Denny 1978, Ost and Kaderly 1986, Dyce and Houlton 1993), screws and wire (Herron 1977), and screws and polymethylmethacrylate (Lewis and others 1997). Anatomic reduction of acetabular fractures decreases the level of post-traumatic osteoarthritis (Hulse and Root 1980, Matta and Merrit 1988). This short communication describes the treatment of 20 dogs (Table 1) using the muscle separation technique during the period 1992 to 2005. Twelve of the dogs were male and eight were female; the age of the dogs ranged from six months to 10 years, with seven dogs aged less than one year. Selection of dogs for the study took into account the weight of the dog; six dogs were over 20 kg bodyweight and seven dogs were under 10 kg bodyweight (Table 1). A further aspect of case selection was the character of the acetabular fracture itself. The muscle separation technique used was based on the dorsal approach of Wadsworth and Henry (1974). An incision was made in line with the greater trochanter in a medial direction slanted cranially; the superficial gluteal was completely isolated and dissected to its origin on the third trochanter and retracted caudally exposing the underlying middle gluteal muscle; and the middle gluteal was exposed and retracted cranially using a Hohman retractor on the ventral ilium. If there was insufficient exposure of the cranial acetabulum using this method some of the muscle fibres were split in the caudal aspect of the middle gluteal and retracted caudally using self-retaining retractors. The deep gluteal muscles were split between fibres and elevated from the fracture site. Further exposure of the caudal acetabulum could be achieved by incising the internal obturator/gemelli muscle insertions. The separation and retraction of the muscles was continued down to the fracture site and maintained using self-retaining retractors. Soft tissue attachments were removed from the dorsal acetabular rim using a periosteal elevator. The joint capsule of the acetabulum was incised at the site of the fracture, if not already torn, to view the hip joint. Trial reduction using Hohman retractors combined with movement of the femur was applied to confirm that reduction could be achieved. This usually involved pushing some of the fragments ventrally using a hand-held retractor or elevator, while simultaneously levering the femur or other acetabular fragment. A plate was aligned on the reduced acetabulum and contoured as required. The plates chosen were either acetabular plates, reconstruction plates or malleable cuttable plates (Veterinary Instrumentation). A screw was placed into the caudal fragment following drilling and tapping within a predetermined plate hole, but not fully tightened down. A