Here’s how overuse, damage or disease can cause inflammation inside the knees. Know what’s the science behind it and how to recover!
Have you experienced pain inside the knee ever? It could be a case of Pes anserine bursitis.First described in 1937, it is a condition caused by repetitive friction and stress or direct trauma to the pes bursa and surrounding structures, especially in the setting of obesity, arthritis, or anatomic dysmorphism of the knee joint. It may result in acute inflammation and fluid distension of this bursa.
In particular, sports may make one prone to pes-anserine inflammatory conditions, including running or sprinting, basketball, and racquet sports.
The prevalence of pes anserine bursitis is variable (2.5-70%) in patients with knee pain. However, in one large study of over 10,000 persons, pes anserine pain was prevalent in approximately one-third of 1% of these individuals.
The origin
The term “pes anserine” (Latin for goose foot) refers to the common insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the anteromedial surface of the proximal tibia.It inserts onto the proximal anteromedial tibia about 5cm distal to the medial tibial joint line.
The pes bursa is a synovial lined sac that lies deep to the pes anserine and superficial to the tibial attachment of the medial collateral ligament (MCL) and the medial tibial plateau and this bursa does not communicate with the knee joint. When the three muscles that form the pes anserine are contracted, it results in knee flexion and tibial internal rotation.
Clinical presentation & risk factors
- Patients usually complainabout aggravating factors including activities that require movements like flexion and Internal rotation (IR), as well as external rotation (ER) and adduction.
- Pivoting, kicking, squatting or quick movements from side to side, such as in the sports mentioned earlier may also cause further irritation.
- Ascending or descending stairs or rising from a seated position may also aggravate their symptoms.
- Based upon clinical experience and limited available evidence, risk factors for pes anserine bursitis includeobesity, diabetes, knee osteoarthritis, and knee malalignment.
Differential diagnosis
- Proximal medial tibial pain
- Swelling 4-5 cm distal to the medial tibial joint line
- Muscle Weakness
- Decreased range of motion of the knee joint
- Tenderness to palpation in the region of their pes anserine bursa and may have local oedema
- Stress-fracture of the shin bone
- Patellofemoral syndrome
- Medial meniscus lesion and osteoarthritis
- Panniculitis: Occurs in obese individuals, and causes painful inflammation of subcutaneous fat at night
- Semimembranosus tendinitis will often occur as a running injury
- Medial Plica Syndrome
- Extra-articular cystic lesions: synovial cyst, ganglionic cyst, parameniscal cyst, synovial sarcoma
- Semimembranosus bursitis
- Tibial collateral ligament bursitis
Diagnosis
- Diagnosis of pes anserine bursitis is clinical, but diagnostic studies such as ultrasonography, computed tomography (CT) and magnetic resonance imaging (MRI) can be used to diagnose this condition.
- Sinography (radiography of a sinus following the injection of a radiopaque medium) is the best method for establishing the diagnosis when other imaging modalities, including MRI and CT, are not feasible.
- A Lidocaine/Corticosteroid injection in the area of the bursa which will help determine the contribution of this pathology to the patient’s overall knee pain.
- On physical examination, the pes anserine bursa can be palpated at a point slightly distal to the tibial tubercle and about 3-4 cm medial to it (about 2 fingerbreadths).
- Tenderness will likely be present in the medial knee joint and may extend along the proximal, medial tibial region.
- With knee flexion to 90 degrees, tenderness may be palpated along the medial tendinous structures of the pes anserine group as they travel to insert along the medial tibial region.
- With the sports-related variant of pes anserine bursitis, symptoms may be reproduced by means of resisted internal rotation and resisted flexion of the knee.
- With the chronic variant in older adults, flexion or extension of the knee usually does not elicit pain.
Treatment
- The initial treatment of pes anserine bursitis should include relative rest of the affected knee and non-steroidal anti-inflammatory drugs (NSAID).
- Additional modalities, including local injection of a corticoid such as methylprednisolone, are indicated in some cases.
- Intra-bursal injection of local anaesthetics, corticosteroids, or both constitutes a second line of treatment.
- Surgical treatment is indicated in cases with failure to conservative treatments or if the bursa gets infected, Simple incision and drainage of the distended bursa can improve symptoms in some reported cases.
Physiotherapy interventions
- To reduce the pain caused by the bursitis, the patient can be advised to restrict movement and alternately apply ice during the inflammatory phase.
- An ice massage of 15 minutes every 4-7 hours will reduce the inflammation.
- Ultrasound Therapy has been documented as effective in the reduction of the inflammatory process in pes anserine bursitis.
- An elastic bandage can be wrapped around the knee to reduce swelling or prevent swelling from occurring and avoid friction, stair climbing, and other aggravating movements.
- Once pain subsided, exercises which include stretching exercises such as hamstring stretch, standing calf stretch, standing quadriceps stretch, hip adductor stretch, heel slide, quadriceps isometrics, and hamstring isometrics can be advised.
- Further progression of exercises includes closed-kinetic chain exercises such as single-knee dips, squats, and leg presses.
- Resisted leg-pulls using elastic tubing are also included.
- The closed-kinetic chain exercises are also a recommended method to prevent the development of collateral knee instability, which occurs to be a risk factor of Pes anserinus bursitis/tendinopathy.
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