Short-axis lateral ultrasound-guided hip injection is a safe, reliable, and reproducible technique, validated by magnetic resonance arthrography in a large clinical cohort

The aim of this study was to validate the safety and reliability of a lateral short-axis ultrasound-guided intra-articular hip injection (IAHI) technique using magnetic resonance arthrography (MRA). A retrospective review was conducted of 273 hips that underwent ultrasound-guided IAHI followed by MRA between May 2012 and October 2023. All injections were performed using a lateral short-axis image parallel technique with the hip in slight flexion and internal rotation. Successful intra-articular injection was assessed based on contrast distribution on axial MRA. Contrast patterns were classified descriptively, and intra- and interobserver reliability were evaluated using Cohen's κ statistic. Procedure-related complications were recorded. The cohort included 148 women and 125 men with a mean age of 40.3 ± 14.1 years. Successful intra-articular contrast enhancement was achieved in 271 of 273 hips (99.3%). Contrast distribution was graded as excellent in 195 hips (71.4%), good in 70 (25.6%), fair in 6 (2.2%), and poor in 2 (0.7%). No infections occurred. One transient femoral nerve palsy resolved within several hours. Intra- and interobserver agreement for contrast assessment was substantial (κ = 0.60–0.73). The lateral short-axis ultrasound-guided hip injection technique provides a safe and highly reliable method for intra-articular access, as validated by MRA in a large clinical cohort, and demonstrates acceptable reproducibility for diagnostic hip injections. • A lateral short-axis ultrasound-guided technique enables reliable hip injection. • Magnetic resonance arthrography confirmed a high rate of intra-articular contrast delivery. • The technique demonstrated acceptable safety and reproducibility.