No Benefit of the Two-incision THA over Mini-posterior THA: A Pilot Study of Strength and Gait

Proponents of the two-incision minimally invasive approach for THA have claimed recovery is dramatically better than after other methods of THA, but this has not been confirmed with any objective data. We designed a prospective randomized trial of the two-incision THA versus the mini-posterior technique to determine whether patients having two-incision THA, when compared with patients having mini-posterior THA, had evidence of less muscle damage as reflected by changes in hip muscle strength after surgery, a less antalgic gait as reflected by changes in the single-leg stance time and walking velocity, and better hip function as reflected by changes in the hip moments during level walking and stair climbing as assessed by comprehensive gait analysis testing. Twenty-one patients, including 13 men and eight women, were prospectively randomized to either the two-incision or the mini-posterior approach and completed preoperative and 6-week postoperative three-dimensional gait analyses and isometric strength testing. We found no evidence that patients who had two-incision THA had less muscle damage, less antalgic gait, or better gait kinematics than patients who had mini-posterior THA. Instead, when there was a difference in strength or gait parameters, it was the patients who had mini-posterior THA who tended to have quicker recovery.

Level of Evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.