Abstract
The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinous muscles on the medial side of the tibia. This bursa may exist as a single bursal sac or, in some patients, as a multisegmented series of loculated sacs. The pes anserine bursa is susceptible to the development of inflammation from overuse, misuse, or direct trauma. If inflammation of the pes anserine bursa becomes chronic, calcification may occur. Rarely, the pes anserine bursa becomes infected.
With trauma to the medial knee, the medial collateral ligament is often involved, along with the pes anserine bursa. This broad, flat, bandlike ligament runs from the medial condyle of the femur to the medial aspect of the shaft of the tibia, where it attaches just above the groove of the semimembranosus muscle; it also attaches to the edge of the medial semilunar cartilage. The medial collateral ligament is crossed at its lower part by the tendons of the sartorius, gracilis, and semitendinosus muscles.
Patients with pes anserine bursitis present with pain over the medial knee joint and increased pain on passive valgus and external rotation of the knee. Activity, especially that involving flexion and external rotation of the knee, makes the pain worse, whereas rest and heat provide some relief. Often, patients are unable to kneel or walk down stairs. The pain of pes anserine bursitis is constant and is characterized as aching; it may interfere with sleep. Coexistent bursitis, tendinitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee.
Keywords
pes anserine bursitis, knee pain, patellar tendon, overuse injury, diagnostic sonography, ultrasound guided procedure, magnetic resonance imaging, nonsteroidal antiinflammatory drugs, septic arthritis, Rice bodies
ICD-10 CODE M76.899
The Clinical Syndrome
The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinous muscles on the medial side of the tibia ( Fig. 118.1 ). This bursa may exist as a single bursal sac or, in some patients, as a multisegmented series of loculated sacs. The pes anserine bursa is susceptible to the development of inflammation from overuse, misuse, or direct trauma. If inflammation of the pes anserine bursa becomes chronic, calcification may occur. Rarely, the pes anserine bursa becomes infected.
With trauma to the medial knee, the medial collateral ligament is often involved, along with the pes anserine bursa. This broad, flat, bandlike ligament runs from the medial condyle of the femur to the medial aspect of the shaft of the tibia, where it attaches just above the groove of the semimembranosus muscle; it also attaches to the edge of the medial semilunar cartilage. The medial collateral ligament is crossed at its lower part by the tendons of the sartorius, gracilis, and semitendinosus muscles.
Signs and Symptoms
Patients with pes anserine bursitis present with pain over the medial knee joint and increased pain on passive valgus and external rotation of the knee. Activity, especially that involving flexion and external rotation of the knee, makes the pain worse, whereas rest and heat provide some relief. Often, patients are unable to kneel or walk down stairs ( Fig. 118.2 ). The pain of pes anserine bursitis is constant and is characterized as aching; it may interfere with sleep. Coexistent bursitis, tendinitis, arthritis, or internal derangement of the knee may confuse the clinical picture after trauma to the knee.
Physical examination may reveal point tenderness in the anterior knee just below the medial knee joint at the tendinous insertion of the pes anserine. Swelling and fluid accumulation surrounding the bursa are often present. Active resisted flexion of the knee reproduces the pain. Sudden release of resistance during this maneuver causes a marked increase in pain.
Testing
Plain radiographs and ultrasound imaging of the knee may reveal calcification of the bursa and associated structures, including the pes anserine tendon, findings consistent with chronic inflammation. Magnetic resonance imaging (MRI) and ultrasound imaging are indicated if internal derangement, an occult mass, or a tumor of the knee is suspected ( Figs. 118.3 through 118.5 ). Electromyography can distinguish pes anserine bursitis from neuropathy, lumbar radiculopathy, and plexopathy. The injection technique described later serves as both a diagnostic and a therapeutic maneuver.
