Background and indications: The hip is one of the deepest joints, and ultrasoundguided injections may be challenging. Nevertheless, ultrasound has an advantage over fluoroscopy in performing intra-articular hip injections. The need for intra-articular access may be for the purpose of arthrograms, corticosteroid injections, viscoelastic supplementation and, in the future, cellular and other biologic therapies. Intra-articular hip injections may also be necessary to rule out hip pain from other potential sources of pain such as the spine, the sacroiliac joint, and other soft tissues. Injections based on surface anatomy are inaccurate in 20% to 50% of cases, and needles dangerously pass within 4 to 5 mm of the femoral nerve.¹

The accuracy of ultrasound-guided hip injections has been evaluated. Pourbagher et al.² performed 30 sonographic-guided hyaluronidate injections with contrast-enhanced computed tomography (CT) documentation and demonstrated accuracy in all injections. Smith et al.³ reported ultrasound-guided arthrography with an average procedure time of 112 seconds and a 97% rate of accuracy.

Anatomy: The hip joint is a ball and socket joint consisting of the femoral head and acetabulum. The acetabulum is surrounded by the triangular fibrocartilaginous labrum, which is clearly visible on ultrasound exam (Fig. 68.1). The femoral head is a rounded structure that is two-thirds of a sphere covered by hyaline cartilage except for the region at the fovea. The anterior synovial recess extending to the neck of femur is the most accessible target for ultrasound-guided injections (Fig. 68.2). The neurovascular bundle of the femoral vein, nerve, and artery lies medially to the hip joint. The articular capsule is a strong and dense fibrous structure that thickens closer to the femoral head and tapers as it extends over the femoral neck and attaches to the intertrochantEric region. The iliofemoral ligament forms the superior band and an inferior band, which together is called the Y ligament Bigelow. This ligament reinforces the anterior aspect of the capsule.⁴