Improving Cephalad Lag Screw Placement in the Femoral Head During Cephalomedullary Nailing Using a Novel Augmented Reality System.

Objectives: To measure the effect of a novel augmented reality software designed to aid in lag screw placement into the femoral head for cephalomedullary nails.

Design: Retrospective cohort study.

Setting: Single Level I trauma center.

Patients: Between November 2017 and December 2020, 114 consecutive patients with a hip fracture that underwent repair with a cephalomedullary nail by one of 2 orthopaedic trauma surgeons were reviewed. Fracture classifications included OTA/AO 31-A1, 31-A2, 31-A3, and 31-B3.

Intervention: The first 57 patients underwent fracture repair without the software (control) and the subsequent 57 patients underwent repair with use of the augmented reality software (AR).

Main Outcome Measurements: Tip apex distance (TAD) and femoral head zone (AP: superior, center, inferior; Lateral: anterior, center, posterior) were measured using standardized techniques.

Results: The mean TAD was lower for the AR versus control cohort (10.7 ± 2.9 mm vs. 15.4 ± 3.8 mm; P < 0.001). TAD <10 mm for AR versus control: 25 (43.9%) versus 3 (5.3%), P < 0.001. TAD <15 mm for AR versus control: 50 (87.7%) versus 44 (77.2%), P < 0.001. On the AP view, center position was achieved in 50.9% versus 7.0% of cases for the AR versus control cohort, respectively. On the lateral view, center position was achieved in 68.4% versus 12.3% of cases for the AR versus control cohort, respectively.

Conclusion: This study suggests that use of the novel augmented reality software for assistance in lag screw positioning within the femoral head improves overall TAD and ability to achieve the center-center position.

Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.