AJVR • Vol 79 • No. 11 • November 2018 1217 H ip dysplasia, a common orthopedic disease of me- dium- and large-breed dogs, includes subluxation of the hip joint, leading to osteoarthritis. 1–4 Several of the surgical procedures used to manage hip dysplasia are aimed at decreasing or eliminating subluxation of the hip joint to prevent or slow the development of osteoarthritis. 1,5 Juvenile pubic symphysiodesis sur- gically induces premature closure of the pubic por- tion of the ischiopubic symphysis without affecting growth of the caudal portion of the symphysis and the acetabula. 6–8 When JPS is performed at an early age, it results in ventrolateral rotation of the acetabu- lar rims, thereby increasing dorsal coverage of the femoral heads and potentially decreasing subluxation of the hip joint. 6,7,9,10 Three-dimensional assessment of the influence of juvenile pubic symphysiodesis on the pelvic geometry of dogs Anna E. Dunlap DVM Kyle G. Mathews DVM, MS Bethany L. Walters DVM Kent A. Bruner DVM Hongyu Ru PhD Denis J. Marcellin-Little DEDV Received November 14, 2017. Accepted March 16, 2018. From the Departments of Clinical Sciences (Dunlap, Mathews, Walters, Marcellin-Little) and Population Health and Pathobiology (Ru), College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607; and Canine Assistants, 3160 Francis Rd, Milton, GA 30004 (Bruner). Dr. Walters’ present address is Triangle Veterinary Referral Hospital, 608 Morreene Rd, Durham, NC 27705. Dr. Marcellin- Little’s present address is Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616. Address correspondence to Dr. Marcellin-Little (djmarcel@ucdavis.edu). OBJECTIVE To evaluate the 3-D geometry of canine pelves and to characterize the long- term effects of juvenile pubic symphysiodesis (JPS) on pelvic geometry by comparing the pelvic confguration between littermates that did and did not undergo the procedure. ANIMALS 24 Labrador Retriever, Golden Retriever, or Labrador Retriever–Golden Retriever crossbred service dogs from 13 litters. PROCEDURES At 16 weeks old, puppies with a hip joint distraction index ≥ 0.5 were randomly assigned to undergo thermal JPS (n = 9), mechanical JPS (7), or a sham (control) surgical procedure (8). Ten years later, each dog underwent a CT scan of the pelvic region. Modeling software was used to create 3-D reconstructions from the CT scans, and various pelvic measurements were made and compared among the 3 treatments. RESULTS Compared with the control treatment, thermal and mechanical JPS in- creased the hemipelvis acetabular angle by 4°, the acetabular angle of lat- eral opening by 5°, and the orientation of the medial acetabular wall in a transverse plane by 6°, which indicated that JPS increased dorsal femoral head coverage by the acetabulum. Both JPS procedures decreased the pelvic canal area by approximately 20% and acetabular inclination by 6° but did not alter acetabular retroversion. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that thermal and mechanical JPS were equally effective in altering the 3-D pelvic geometry of dogs. These fndings may help guide future studies of alternatives for optimizing canine pelvic anatomy to mini- mize the risk of hip dysplasia and associated osteoarthritis. (Am J Vet Res 2018;79:1217–1225) The geometry of the pelvis and acetabula has an important role in the pathogenesis of osteoarthritis secondary to hip dysplasia in both dogs and human patients. 2,6,11 Pelvic conformation has been evaluated radiographically and with cross-sectional imaging (eg, CT). The accuracy of those methods is negatively affected by variability in patient positioning and the imaging protocol used. 2,6,9 For example, geometric analysis of the acetabula is particularly challenging when 2-D radiographic or CT images are used. 2–4 Three-dimensional reconstruction of CT images elim- inates the shortcomings of 2-D images and offers a more detailed and accurate representation of skeletal changes. 2,4,12 In human medicine, 3-D reconstruc- tion of the pelvis and acetabula has led to advances in the understanding of hip dysplasia in children, aided in the reconstruction of acetabular fractures, and improved preoperative planning for total hip arthroplasty. 4,13–15 The purpose of the study reported here was to evaluate the 3-D geometry of canine pelves and to ABBREVIATIONS ALO Angle of lateral opening DARA Dorsal acetabular rim angle DI Distraction index HPAA Hemipelvis acetabular angle JPS Juvenile pubic symphysiodesis Unauthenticated | Downloaded 02/23/23 03:37 PM UTC