Traction versus distension for distraction of the joint during hip arthroscopy.

Distraction is the most popular technique used in hip arthroscopy. It has been postulated that, if adequate distraction cannot initially be achieved with traction, it will be overcome by distension. The purpose of this study is to quantitate the additive effects of traction and distension in achieving distraction of the hip joint for arthroscopy. Eleven consecutive patients undergoing hip arthroscopy in the supine position on a fracture table were studied. Radiographs of the hip were obtained before and immediately after applying 50 pounds of traction. The hip was then immediately distended with 40 mL saline, and a third radiograph was obtained. After correcting for magnification, distraction was measured for traction alone (DT) and traction plus distension (DTD). A paired t-test was used to compare DT and DTD. Additionally, the ratio of distraction attributed to distension was compared with distraction attributed to traction ([DTD--DT]/DT) and was defined as the delta percent (delta %). Adequate distraction for arthroscopy was able to be achieved in all cases. Distraction due to traction alone (DT) ranged from 2.8 mm to 10.3 mm, with an average of 6.2 mm. Distraction due to traction plus distension (DTD) ranged from 4.8 m to 10.3 mm, with an average of 7.2 mm. The difference between DT and DTD was statistically significant (P < .05). The change in distraction due to distension (delta %) ranged from 0% to 81% with an average of 22%. This study shows that distension may facilitate distraction but the degree is variable.