Summary
This randomized control trial found that using 3D-printed models for arthroscopic hip surgery improved pre-operative planning, enhanced intra-operative visualization, and resulted in better CAM resection compared to traditional imaging methods.
Abstract
Purpose
Femoroacetabular impingement (FAI) is a painful condition caused by abnormal contact between the acetabulum and the femur. CAM-type impingement, due to abnormal femur morphology, can cause labral and cartilage damage, and contribute to osteoarthritic changes in the hip. Arthroscopic surgery can treat FAI; however, the anatomy of the hip joint makes visualization during surgery challenging. Innovations like 3D printing offer an avenue for advancing surgical planning and improving intra-operative visualization, however the use of 3D models for hip arthroscopy remains unexplored in the literature. This randomized control trial sought to determine whether 3D-printed models enhance pre-operative planning and intra-operative identification of CAM-type FAI, thereby improving resection over traditional imaging.
Methods
This randomized control trial included 126 patients who underwent arthroscopic hip surgery for CAM-type FAI. Patients were randomized to either a 3D Print (n = 63) or No Print (n = 63) group. The primary outcome was CAM resection measured by alpha-angle on post-operative AP, 45° Dunn and frog-leg X-ray views. The secondary outcomes were the number of times the 3D print and traditional imaging (X-Ray, CT, 3D CT, MRI or MRA) were referenced intra-operatively, International Hip Outcome Tool (iHOT-33) scores, and rate of revision surgery.
Results
There were no between-groups differences at baseline. On all radiographic views, alpha angle improved from pre- to post-operative in both groups. Alpha angle was lower on all x-ray views in the 3D Print group. Within the 3D Print group, 3D models were referenced more than all other imaging modalities (p<0.001). iHOT scores improved from pre- to post-operative for both groups (p<0.001), with no between-groups differences. Two patients underwent revision surgery, both in the No Print group (p=0.355).
Conclusions
Although both groups had significant pre- to post-operative improvements in alpha angle and patient-reported outcomes, the use of 3D models resulted in higher quality CAM resection. 3D models were referenced more frequently during surgery than traditional imaging. 3D models are a valuable tool for both pre- and intra-operative planning for arthroscopic FAI surgery.