Reliability of a simple fluoroscopic image to assess leg length discrepancy during direct anterior approach total hip arthroplasty

Figure 1 Intra-operative fluoroscopy image capture. Representative image of observer obtained leg length discrepancy measurements on a saved intra-operative fluoroscopic view of the pelvis. Image capture was performed by the OEC image intensifier intra-operatively as described. Shown is a line drawn through bilateral radiographic teardrops with perpendicular lines to the medial prominence of bilateral lesser trochanters.

Figure 2 Post-operative x-ray image capture. Representative image of observer obtained leg length discrepancy measurements on a corresponding post-operative anterior-posterior x-ray of the pelvis. Single line drawn through bilateral radiographic teardrops with perpendicular lines to the medial prominence of bilateral lesser trochanters.

Figure 3 Measured leg length discrepancy. A: Measured leg length discrepancy based on teardrop reference point. Comparison showing mean x-ray leg length discrepancy (LLD) and fluoroscopic LLD using radiographic teardrop reference points as measured by two independent observers. Corresponding linear regression r² value of 0.56; B: Measured leg length discrepancy (LLD) based on ischium reference point. Comparison showing mean x-ray and fluoroscopic LLD using ischium references points as measured by two independent observers. Corresponding linear regression r² value of 0.87. LLD: Leg length discrepancy.