Fluoroscopy-Assisted Computer Navigation Accurately Determines Cup Position and Leg Length for Anterior Hip...

Area of Science:

• Orthopedic Surgery
• Medical Technology
• Surgical Navigation

Background:

• Fluoroscopy-assisted computer navigation is a recent advancement for intraoperative assessment in total hip arthroplasty.
• Limited studies compare the accuracy of this navigation software with postoperative radiographic assessments.

Purpose of the Study:

• To prospectively evaluate the accuracy of fluoroscopy-assisted computer navigation for intraoperative cup positioning and leg-length discrepancy (LLD) in anterior total hip arthroplasty.
• To compare navigated measurements with postoperative radiographic findings.

Main Methods:

• 211 patients undergoing navigated anterior total hip arthroplasty were enrolled.
• Intraoperative navigated measurements of cup inclination/anteversion and LLD were compared with postoperative anteroposterior radiographs.
• Statistical analysis included Student's t-test for continuous variables and Fisher's exact test for categorical variables.

Main Results:

• 99.1% of cups were within the desired "safe zone" intraoperatively versus 94.3% postoperatively (P=.01).
• Intraoperative navigation achieved LLDs within ±2 mm in 82% of hips, compared to 65% on postoperative radiographs (P=.0001).
• Both intraoperative navigation and postoperative radiographs showed high accuracy for LLDs within ±5 mm (100% vs 98%, P=.12).

Conclusions:

• The fluoroscopy-assisted computer navigation platform demonstrated accuracy in assessing intraoperative cup position and LLD during anterior total hip arthroplasty.
• Surgeons must consider fluoroscopic technique, landmark positioning, and limitations like parallax effect for effective use.