Pes anserinus syndrome is the name given to pain occurring on the inside of the lower leg just below the knee joint. There is irritation in the tendon, and the synovial bursa may also be inflamed. Pain worsens under stress, such as when climbing stairs, when crouching, or after walking/running and jumping. Pes anserine bursitis occurs when the bursa — or fluid-filled sac — inside your knee joint becomes irritated and produces too much fluid. The bursa then swells, causing knee pain and tenderness. This condition is sometimes called pes anserinus pain syndrome (PAPS). The symptoms of pes anserine bursitis include Pain slowly developing on the inside of your knee and/or in the center of the shinbone, approximately 2 to 3 inches below the knee joint. Pain increases with exercise or climbing stairs. Puffiness or tenderness to the touch in this area.
Other Names
- Pes Anserine Pain Syndrome (PAPS)
- Anserine bursitis
- Pes Anserine Pain
- Pes Anserinus Tendinitis or Bursitis (PATB)
Pathophysiology
- Mechanical Derangement
- Thought to cause local inflammation to surround tendinous structures
- Includes Medial Meniscus, Medial Collateral Ligament which may irritate pes anserine bursa
- Overuse
- Thought to be due to repetitive flexion, adduction
- Other implicated etiologies
- Direct trauma
- Obesity
Pathoanatomy
- Pes Anserine
- “Pes Anserine” comes from the Latin referring to “goose’s foot”
- Conjoined tendinous attachment of Semitendinosus, Gracilis, and Sartorius
- Bursa between proximal medial Tibia and the insertion point of the 3 tendons[1]
Associated Conditions
- Knee Osteoarthritis
- Specifically, the medial joint space
- Up to 90% of cases
- Sports]
- Running
- Basketball
- Basketball
- Racquet Sports
- Racquet sports
- Obesity
- Diabetes Mellitus
Differential Diagnosis
- Fractures
- Distal Femur Fracture
- Patellar Fracture
- Tibial Plateau Fracture
- Dislocations & Subluxations
- Patellar Dislocation (and subluxation)
- Knee Dislocation
- Proximal Tibiofibular Joint Dislocation
- Muscle and Tendon Injuries
- Quadriceps Contusion
- Iliotibial Band Syndrome
- Quadriceps Tendonitis
- Patellar Tendonitis
- Popliteus Tendinopathy
- Extensor Mechanism Injury
- Patellar Tendon Rupture
- Quadriceps Tendon Rupture
- Patellar Fracture
- Ligament Pathology
- ACL Injury
- PCL Injury
- MCL Injury
- LCL Injury
- Meniscal Pathology
- Posterolateral Corner Injury
- Multiligament Injury
- Arthropathies
- Knee Osteoarthritis
- Septic Arthritis
- Gout
- Bursopathies
- Prepatellar Bursitis
- Pes Anserine Bursitis
- MCL Bursitis
- Infrapatellar Bursitis
- Patellofemoral Pain Syndrome (PFPS)/ Anterior Knee Pain)
- Chondromalacia Patellae
- Patellofemoral Osteoarthritis
- Osteochondral Defect Knee
- Plica Syndrome
- Infrapatellar Fat Pad Impingement
- Patellar Instability
- Neuropathies
- Saphenous Nerve Entrapment
- Other
- Bakers Cyst
- Patellar Contusion
- Pediatric Considerations
- Patellar Apophysitis (Sinding-Larsen-Johansson Disease)
- Patellar Pole Avulsion Fracture
- Tibial Tubercle Avulsion Fracture
- Tibial Tuberosity Apophysitis (Osgood Schalatters Disease)
Diagnosis
- History
- Medial knee pain
- Worse withstanding, stairs, crossing leg
- Subjective weakness, diminished range of motion
- Physical Exam
- Swelling may or may not be present
- Tenderness over the pes anserine at the medial, proximal tibia, with the knee at 90°
- In extension, tenderness may be over the medial joint line
- Pain with resisted internal rotation and flexion of the knee
- Location: 3-4 cm medial to the tibial tubercle, 3 cm below anteromedial tibial plateau
- Special Tests
Pes Anserine bursitis with fluid in the bursa seen in long axis (arrow)
Radiographs
- Standard Knee Radiographs
- Findings
- Underlying osteoarthritis is common
Ultrasound
- Findings
- Swelling
- Bursal fluid
- Thickened pes anserine, especially in patients with knee OA[5]
MRI
- Not typically indicated
- Findings[6]
- Increased bursal fluid
- Thickened bursal wall
- Surrounding tissue edema
- Abnormal wall / surrounding tissue enhancement
Treatment
Nonoperative
- Indication
- The vast majority of cases
- When appropriate, treatment should be directed at the underlying etiology
- For example, osteoarthritis
- Relative rest
- Activity modification
- NSAIDS
- Weight Loss
- Physical Therapy
- Emphasis on strengthening quadriceps muscles
- Corticosteroid Injection
- One small study showed potential benefit[7]
- Consider an intra-articular injection for knee OA + intra-bursa injection for pes anserine pain
Operative
- Indications
- Rarely, failure of conservative treatment
- Technique
- Bursal incision and drainage
- Bursectomy
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