EFFECT OF PUBIC SYMPHYSIODESIS ON ACETABULAR ROTATION AND PELVIC DEVELOPMENT IN GUINEA-PIGS

Objective-To evaluate the effect of premature closure of the pubic sym physis on pelvic development. Animals-18, 21-day-old male guinea pigs. Procedure-The pubic symphysis was surgically approached in 10 guinea pigs of the symphysiodesis group and in 4 of the sham-operated group; 4 guinea pigs served as unoperated controls. The pubic symphysis was d estroyed by use of electrocautery in the 10 guinea pigs of the symphys iodesis group. Ail guinea pigs were allowed to grow to skeletal maturi ty and were euthanatized at 33 weeks of age. Body weight was recorded throughout the study and was compared between groups. Histologic exami nation of the symphyses confirmed premature closure of the pubic symph yseal growth plates in guinea pigs of the symphysiodesis group. Pelvic measurements taken from pretreatment radiographic views and from vide o images of harvested pelves were compared between groups. Results-The re were no significant differences between groups with regard to pretr eatment radiographic variables, rate of weight gain, or body weight at any time. Pubic symphysiodesis resulted in significant narrowing of t he caudal aspect of the pelvis, narrowing and shortening of the pubic bones, and outward rotation of the acetabula. Conclusions-The pubic sy mphyseal growth plates contribute significantly to development of the pelvis. Premature closure of these growth plates (pubic symphysiodesis ) results in outward rotation of the acetabula, which might be benefic ial in some cases of canine hip dysplasia; however, this rotation is a ccompanied by concomitant narrowing pf the caudal aspect of the pelvis .