Effectiveness of Flat Panel Fluoroscopy in Direct Anterior Total Hip Arthroplasty: A Comparison to Image Intensifier Fluoroscopy with Radiopaque Grid

The use of traditional, image-intensifier fluoroscopy with a radiopaque grid during direct anterior total hip arthroplasty (DA THA) has demonstrated reduced variability in component positioning and operative time compared to fluoroscopy without a grid. A disadvantage of image intensifier fluoroscopy is spatial distortion, particularly as compared to flat panel fluoroscopy systems. The purpose of this study is to determine whether flat panel fluoroscopy decreases variability in component positioning during DA THA compared to use of traditional grid fluoroscopy We retrospectively reviewed 70 consecutive, DA THAs between February 2020 and February 2021: 36 using flat panel fluoroscopy, 34 using traditional, image intensifier fluoroscopy with a grid. Radiographs were independently reviewed by two authors to identify components exceeding goal parameters: cup abduction of 40 +/- 10 degrees, as well as offset and limb lengths within 10 mm of the contralateral side. A secondary limb length goal of 5 millimeters was set to further distinguish between the groups. Binary values for goal parameter achievement were assigned for each THA. No significant difference was observed in the number of hips that met goals for cup abduction (100% vs 97%, p= 1.00), hip offset (88% vs 88%, p= 1.00), limb length (91% vs 94% (+/-10mm), p=0.669, 65% vs. 72% (+/-5mm), p=0.498), or for the number of hips that met all three component goals (79% vs 80%, p= 1.00). No significant difference in operative time was noted between the two groups (110.2 min vs 100.9, p= 0.76). We demonstrated no significant difference in component positioning in DA THAs utilizing flat panel fluoroscopy as compared to using traditional fluoroscopy with a grid.