Fri., 10/19/07 Pelvis, Paper #26, 11:22 am OTA-2007
Single-Leg Stance (Flamingo) Radiographs to Assess Pelvic Instability: How Much Motion Is Abnormal?
David N. Garras1 (n); Joshua T. Carothers, MD2 (n); Steven A. Olson, MD2 (n);
1Duke University School of Medicine, Durham, North Carolina, USA (n);
2Division of Orthopaedic Surgery, Duke University Medical Center,
Durham, North Carolina, USA
Introduction: Chronic pelvic instability is a relatively uncommon cause of pelvic and low back pain. Patients present with feelings of instability and mechanical symptoms. Static radiographs are often inadequate for diagnosis, requiring dynamic views of the pelvis. The present study sought to determine the amount of physiologic motion that is present in the pubic symphysis in a group of males, nulliparous, and multiparous females. This will help define the limits of physiologic motion to aid in diagnosis of pelvic instability.
Materials and Methods: In this study, 45 asymptomatic adults were evaluated with a standing AP pelvis radiograph as well as right and left single-leg stance AP pelvis radiographs. Patients completed a questionnaire to determine eligibility for participation and an examination to exclude certain physical anomalies that might alter radiographic findings.
Results: Total translation (TT) at the pubic symphysis was measured by three blinded observers. The mean total pubic translation was 1.4 mm (± 1.0), 1.6 mm (± 0.8), and 3.1 mm (± 1.5) for males, nulliparous, and multiparous females, respectively. There was no significance between males and nulliparous females (P = 0.63). Multiparous females had significantly more translation from nulliparous females (P = 0.002) and males (P = 0.0005). There was significance between the number of pregnancies and TT (P <0.0001).
Discussion: Our findings support the use of single-leg stance radiographs for evaluation of pelvic motion. The method of measurement demonstrates high interobserver reliability and statistically significant differences in physiologic ranges between males and nulliparous, with respect to multiparous, females. These ranges provide a standard whereby single-leg stance radiographs can be evaluated for pathologic motion.
If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options; e-consultant or employee; n-no conflicts disclosed, and *disclosure not available at time of printing.
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing.