ANTOINE BERNARDÉ, DMV, MS, Diplomate ECVS 1 1 Clinique Vétérinaire des Quais, Blois, France. Vet Surg February 2010 39 2 158-164 ABSTRACT Objectives—(1) To compare short-term outcome of juvenile pubic symphysiodesis (JPS) in puppies aged 12–17 weeks with lax hips (group JPS1), in puppies aged 18–22 weeks (group JPS2), and control (group C) puppies; and (2) to document outcome of bilateral pectineus myotomy (PM) associated with JPS in 18–22-week-old puppies (group JPS–PM). Study Design—Prospective study. Methods—Puppies (12–22 weeks) from large and giant breed dogs with a combination of a positive Ortolani sign, poor acetabular coverage (Norberg angle [NA]≤100°), and a subluxation index (SI) >0.5 for one or both hips were selected. Puppies aged <18 weeks were randomly assigned to group JPS1 or C. Puppies aged 18–22 weeks were randomly assigned to group JPS2, JPS–PM, or C. Three to 4 months later, surgery was considered successful in pain-free dogs with negative Ortolani sign, normalized acetabular coverage (NA≥105°), and SI>0.5. Success rates were compared using Fisher's exact tests: JPS1 versus JPS2 versus C; JPS2 versus JPS–PM. Significance was set at P<.05. Results—All dysplastic hips from nonoperated (C) groups were dysplastic at follow-up, meaning that our criteria for case selection were accurate. JPS1 had significantly better success rate than JPS2 (85 versus 17.8%, respectively). JPS–PM dysplastic hips failed to demonstrate a better outcome than JPS2 hips. Clinical Relevance—This study confirms, on a large series of dysplastic hips, the age-dependent effects of JPS, with better results if performed before 18 weeks of age. There is no benefit of adding PM to the procedure in candidates >18 weeks at surgery.