Abstract
BACKGROUND: Restoration of limb length is important in total hip arthroplasty. Clinical evaluation and preoperative templating establish the intended lengthening. The purpose of this study was to assess whether digital fluoroscopic navigation (DF) improved the accuracy of planned lengthening in direct anterior approach total hip arthroplasty (DAA-THA). METHODS: Planned lengthening measurements on 100 consecutive unilateral DAA-THA patients, along with patient characteristics, were prospectively collected by 2 surgeons. One surgeon utilized DF to achieve intended length (n = 50), while the other utilized unaided standard fluoroscopy (SF; n = 50). A third surgeon blinded to the procedures assessed actual limb length using an ipsilateral overlay technique on the 6-week postoperative radiograph. The difference between the mean planned and actual limb lengthening stratified by DF and SF was assessed using bivariate and multivariate statistics. RESULTS: The mean (standard deviation) planned lengthening in DF and SF groups was 3.96 (2.1) and 3.47 (2.2) mm, respectively. The mean (standard deviation) actual lengthening in DF and SF groups was 3.11 (4.0) and 0.68 (4.6) mm, respectively. After accounting for age, sex, body mass index, laterality, and the Bone Index, multivariate regression results showed that the average difference between planned and actual limb lengthening in the DF group was significantly lower than that in the SF group (β = -1.92; 95% confidence interval: -3.51, -0.33; P < .02). A greater percentage of patients in the DF group (66% vs 40%) were within 3 mm of the intended plan (P < .01). CONCLUSIONS: Fluoroscopy helps achieve the intended surgical lengthening in DAA-THA. The use of DF resulted in more accurate execution of lengthening.