Ultrasound Can Determine Joint Distraction During Hip Arthroscopy but Fluoroscopic-Guided Portal Placement Is Superior.

Purpose: To compare joint distraction measured on ultrasound (US) with joint space width (JSW) measured on fluoroscopy in hip arthroscopy and to determine whether ultrasound guidance is as safe and effective as fluoroscopy, the current gold standard, for establishing arthroscopic portals.

Methods: Cadaveric whole-body specimens were positioned supine and subjected to 60 lbs. of unilateral axial traction using a distal femoral Steinman pin. Joint distraction was measured via JSW on fluoroscopic and ultrasound images. A single, fellowship-trained orthopaedic surgeon established anterolateral arthroscopy portals via ultrasound or fluoroscopic guidance in a randomized sequence. Total procedure time, number of times the spinal needle pierced the capsule, and iatrogenic chondral or labral injury were recorded.

Results: Twelve full-body specimens (20 hips) underwent distraction, and 17 hips underwent portal placement with fluoroscopic (n = 8) or ultrasound (n = 9) guidance. JSW measured on ultrasound was significantly less laterally (13.0 vs 9.2 mm, < .001), apically (16.7 vs 9.2 mm, < .001), and medially (17.9 vs 9.2 mm, < .001). Successful portal entry was achieved in every specimen. Average procedure time was 133 ± 51 seconds for the fluoroscopy group and 371 ± 260 seconds for the ultrasound group ( = .026). Fluoroscopic guidance required significantly less needle insertion attempts at 1.13 compared with 3.33 attempts for ultrasound ( = .022). Labral damage was greater in the ultrasound group at 66.67% compared with 12.50% for fluoroscopy ( = .0497).

Conclusions: Joint distraction measured on ultrasound can be used to subjectively determine if the joint is adequately distracted in hip arthroscopy. Ultrasound-guided portal placement was associated with more needle insertion attempts, iatrogenic injury of the labrum, and overall procedure time in comparison to fluoroscopic guidance.

Clinical Relevance: Fluoroscopy is the gold standard to confirm adequate joint distraction, aid in establishing arthroscopy portals, and evaluate resection of the femoral head during hip arthroscopy but exposes the patient to ionizing radiation, requires additional operators in the operating room, and involves the need for a heavy lead shield. Alternatives to fluoroscopy are needed, but ultrasound has not proven superior in our cadaveric model.