It is an inflammation of the anserine bursa (crow’s feet bursa) which is located under the tendons of the crow’s feet muscles, i.e. the semi-tendinous, slender muscles and sartorius. These muscles are inserted on the medial side of the tibia (on its internal face).
This pathology is particularly common in young people who practice sports characterized by sudden lateral movements of the knee and in older people with concomitant lesions in the joints.
How is pes anserine bursitis manifested?
The pain is felt on the inside of the knee joint and gets worse with a passive valgus and external rotation of the knee. Movements, especially flexion and external rotation of the knee, make the pain worse, while rest and warmth provide some relief.
Frequently, the patient is unable to kneel or descend stairs. The pain is constant and dull and vague in nature.
It can create sleep disturbances. The concomitant presence of superficial and deep prepatellar bursitis, tendinitis, arthritis or internal dislocation of the knee can complicate the clinical picture after trauma to the knee joint.
Frequently, the internal lateral ligament is also affected if the patient has suffered trauma to the internal side of the knee joint. If the inflammation becomes chronic, calcification of the crow’s feet bursa may occur.
Diagnosing pes anserine bursitis
First, a consultation with a specialist doctor (orthopedics, rheumatologist or sports doctor). The review reveals:
• Point pain on palpation of the anterior side of the knee just below the inner side, where the crow’s feet tendon is inserted.
• Swelling and a collection of fluid surrounding the bursa are often present.
• Sometimes there is swelling (lump) due to the accumulation of fluid around the bursa anserine.
• When the patient is asked to bend his knee while opposing this flexion, there is the appearance of pain. If you stop resisting this flexion suddenly, you will notice a marked increase in pain.
Additional examinations of crow’s feet bursitis
• Standard knee x-rays: they sometimes show the presence of calcifications of the anserine bursa. There are also calcifications of the tendons of the crow’s feet muscles. This may be the result of a possible chronic inflammation (i.e. spread over a long period).
• MRI of the knee: it is requested when a tumor or other pathology is suspected.
• According to the clinical picture presented, additional biological analyzes, including a blood count (FNS) and a sedimentation rate (VS), can be performed.
How to treat pes anserine bursitis?
Initial treatment for pain and functional impairment due to pes anserine bursitis should include the combination of nonsteroidal anti-inflammatory drugs (NSAIDs) or cyclo-oxygenase-2 inhibitors (COX) -2) and physiotherapy.
The local application of heat and cold can also be beneficial. It is also necessary to avoid repetitive activities that are at the origin of the development of this painful pathology.
In patients who do not meet these therapeutic modalities, infiltration of the crow’s feet bursa with a local anesthetic and a corticosteroid (bupivacaine and methylprednisolone) may constitute the next therapeutic step.