Injection Technique for Quadriceps Expansion Syndrome

Indications and Clinical Considerations

The quadriceps expansion syndrome is characterized by pain at the superior pole of the patella. It is usually a result of overuse or misuse of the knee joint, as in running marathons, or direct trauma to the quadriceps tendon from kicks or head butts during football. The quadriceps tendon also is subject to acute calcific tendinitis, which may coexist with acute strain injuries. Calcific tendinitis of the quadriceps has a characteristic radiographic appearance of “whiskers” on the anterior superior patella.

Patients with quadriceps expansion syndrome experience pain over the superior pole of the sesamoid, more commonly on the medial side. The patient notes increased pain on walking down slopes or down stairs. Activity using the knee makes the pain worse; rest and heat provide some relief. The pain is constant and is characterized as aching and may interfere with sleep. On physical examination, there is tenderness under the superior edge of the patella, occurring more commonly on the medial side. Active resisted extension of the knee reproduces the pain ( Fig. 155.1 ). Coexistent suprapatellar and infrapatellar bursitis, tendinitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee joint.

Plain radiographs are indicated for all patients with quadriceps ligament syndrome pain. On the basis of the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging and ultrasound imaging of the knee are indicated if internal derangement of the joint, complete disruption of the quadriceps tendon, or occult mass or tumor is suspected ( Figs. 155.2 and 155.3 ). Bone scan may be useful to identify occult stress fractures involving the joint, especially if trauma has occurred.

Clinically Relevant Anatomy

The quadriceps tendon is made up of fibers from the 4 muscles that make up the quadriceps muscle: the vastus lateralis, the vastus intermedius, the vastus medialis, and the rectus femoris. These muscles are the primary extensors of the lower extremity at the knee. The tendons of these muscles converge and unite to form a single, exceedingly strong tendon ( Fig. 155.4 ). The patella functions as a sesamoid bone within the quadriceps tendon, with fibers of the tendon expanding around the patella and forming the medial and lateral patella retinacula, which help strengthen the knee joint. These fibers are called expansions and are subject to strain; the tendon proper is subject to the development of tendinitis. The suprapatellar, infrapatellar, and prepatellar bursae also may concurrently become inflamed with dysfunction of the quadriceps tendon.