An in vivo determination of total hip arthroplasty pistoning during activity.

摘要: The purpose of this study was to determine what extent hip joint separation occurs during normal gait on a treadmill and an abduction/adduction leg-lift maneuver in patients who have undergone total arthroplasty (THA). Eight had 10 successful unconstrained THAs (Harris Hip Scores >90) performed successive motions electronically powered leg lift while under fluoroscopy. fluoroscopic video images were analyzed using 3-dimensional model-fitting technique that converts 2-dimensional into real-time images. determined be present if the amount >0.75 mm, calculated linear error. During both activities, all experienced femoral head/acetabular component separation. For gait, maximum 2.8 minimum 0.8 mm (average, 1.2 mm). lift, 3.0 minimal 1.7 2.4 It appears head separates from acetabular but remains contact with superior-most tip component. Potential detrimental effects resulting include premature polyethylene wear loosening. Wear may enhanced because creation multidirectional vectors or excessive loads eccentric pivoting. These data valuable simulation studies better duplicate patterns observed retrieval analysis.