Computer-Assisted Models Effective in Treating FAI

Computer-assisted model are becoming more useful and more accurate in the treatment of patients with femoroacetabular impingement both before and after surgery, according to recent research.

“When we compared the actual surgery performed by a high-volume arthroscopist compared to that which was recommended by the software, we found little differences,” Asheesh Bedi, M.D., said.

Bedi and colleagues studied 49 patients who underwent hip arthroscopy for symptomatic bilateral femoroacetabular impingement (FAI) who underwent preoperative and postoperative computed tomography of the affected hip. Bedi and colleagues created a computer-assisted, 3-D dynamic simulation modeling of the involved hip before and after the procedure. A virtual osteoplasty was then made to establish normal head-neck offset, head sphericity, and to eliminate focal retroversion/over-coverage of the acetabular rim. Alpha angles and cam deformity locations were measured on all radial sequences while 3-D acetabular coverage and dynamic range-of-motion assessments were also performed.

Both virtual and actual osteoplasties in regions of impingement resulted in statistically significant improvements in alpha angles, acetabular impingement areas, hip flexion, internal rotation, and flexion/adduction/internal rotation (FADIR) values. In the revision surgery cohort, pre-revision mean alpha angle was 68 degrees, and mean hip flexion of 115 degrees, internal rotation of 28 degrees, and FADIR of 20 degrees. The virtual correction found substantial residual deformity with a significant difference in post-correction alpha angle of 48 degrees and postoperative range-of-motion with mean flexion of 121 degrees, internal rotation of 34 degrees, and FADIR of 25 degrees.

“Residual deformity can still be a persistent cause for symptoms after surgery, but more important [is] that the software can recognize this and distinguish it from a well-done correction,” Bedi said.