Iliopsoas Bursa Injection

Indications and Clinical Considerations

Bursae are formed from synovial sacs that allow easy sliding of muscles and tendons across one another at areas of repeated movement. These synovial sacs are lined with a synovial membrane, which is invested with a network of blood vessels that secrete synovial fluid. Inflammation of the bursa results in an increase in the production of synovial fluid with swelling of the bursal sac. With overuse or misuse, these bursae may become inflamed, enlarged, and on rare occasions infected. Although there is significant intrapatient variability as to the number, size, and location of bursae, anatomists have identified a number of clinically relevant bursae, including the iliopsoas bursa. The iliopsoas bursa lies medially in the femoral triangle between the psoas tendon and the anterior aspect of the neck of the femur ( Fig. 127.1 ). This bursa may exist as a single bursal sac or in some patients as a multisegmented series of sacs that may be loculated.

The iliopsoas bursa is vulnerable to injury from both acute trauma and repeated microtrauma. Acute injuries frequently take the form of direct trauma to the bursa from seatbelt injuries as well as overuse injuries from activities that require repeated hip flexion, such as javelin throwing and ballet. If the inflammation of the iliopsoas bursa becomes chronic, calcification of the bursa may occur.

The patient with psoas bursitis frequently reports pain in the groin localized to the area just below the crease of the groin anteriorly, with referred pain noted into the hip joint. Often the patient is unable to sleep on the affected hip and may note a sharp, “catching” sensation with range of motion of the hip.

Physical examination may reveal point tenderness in the upper thigh just below the crease of the groin. Passive flexion, adduction, and abduction, as well as active resisted flexion and adduction of the affected lower extremity, reproduce the pain. Sudden release of resistance during this maneuver markedly increases the pain ( Fig. 127.2 ).

Plain radiographs, computed tomography, magnetic resonance imaging (MRI), or ultrasound imaging of the hip and pelvis may reveal calcification of the bursa and associated structures consistent with chronic inflammation ( Figs. 127.3 and 127.4 ). MRI and/or ultrasound imaging is indicated if occult mass or tumor of the hip or groin is suspected. The injection technique described later serves as both a diagnostic and a therapeutic maneuver.

Clinically Relevant Anatomy

The iliopsoas bursa lies between the psoas tendon and the anterior aspect of the femoral neck. The bursa lies deep to the femoral artery, vein, and nerve. The psoas muscle arises from the transverse processes, vertebral bodies, and intervertebral disks of the T12-L5 vertebrae and inserts into the lesser trochanter of the femur. The psoas muscle flexes the thigh on the trunk or, if the thigh is fixed, flexes the trunk on the thigh, as when moving from a supine to sitting position (see Fig. 127.1 ). This action can irritate the iliopsoas bursa, as can repeated trauma from repetitive activity, including running up stairs or overuse of exercise equipment for lower extremity strengthening. The psoas muscle is innervated by the lumbar plexus.