Pes Anserine Bursitis: Symptoms, Types, Causes and Treatment

Pes anserine bursitis is a common and often misunderstood cause of knee pain, particularly affecting adults and those with certain risk factors. This condition involves inflammation of the pes anserine bursa, a small fluid-filled sac located on the inner side of the knee. It can significantly impact daily activities and quality of life if left untreated. In this comprehensive article, we’ll explore the key symptoms, types, causes, and the most up-to-date treatment options for pes anserine bursitis, synthesizing the latest research for a clear and practical guide.

Symptoms of Pes Anserine Bursitis

Pes anserine bursitis can make daily movements and even rest uncomfortable for those affected. Recognizing the symptoms early can help prevent misdiagnosis and avoid unnecessary interventions.

Pain Location	Tenderness Area	Swelling	Source
Medial knee	Inferomedial knee	Present/Absent	1 2 3
Medial joint line	Proximal tibia	Variable	1 2
Inner knee below joint	Medial shin	Sometimes mass	3 6

Table 1: Key Symptoms

Medial Knee Pain

The most prominent and consistent symptom is pain along the medial (inner) side of the knee, particularly just below the joint line. This pain can be sharp or aching and often worsens with activities like climbing stairs, rising from a seated position, or at night 1 2.

Localized Tenderness

Patients frequently report tenderness when pressure is applied to the inner knee, about 2–4 centimeters below the joint line, over the proximal medial tibia. This tenderness is highly suggestive of pes anserine bursitis and helps distinguish it from other knee problems such as meniscal tears 1 2.

Swelling and Mass Formation

Swelling over the bursa area is common but not universal. In some chronic cases, the bursa can enlarge significantly and may even present as a palpable mass. This mass is usually well-demarcated and may be mistaken for other soft-tissue lesions or, rarely, for neoplasms if associated with bony changes 3 6.

Associated Functional Impairments

• Limited range of motion: Movement, especially knee flexion, may become painful and restricted.
• Difficulty with daily activities: Tasks like climbing stairs, walking, or getting up from chairs can be challenging 2 9.
• Night pain and sleep disturbance: Some patients experience increased pain at night, interfering with sleep 2.

Types of Pes Anserine Bursitis

Understanding the different types of pes anserine bursitis is essential for proper diagnosis and management. Although often discussed as a single entity, this condition can present in several distinct forms.

Type	Features	Diagnostic Challenge	Source
Acute	Simple fluid in bursa	Mimics meniscal tear	1 3
Chronic	Mass-like, heterogeneous	Resembles tumors	3 6
Pigmented Villonodular	Benign proliferative lesion	Diagnostic rarity	4 5
Syndrome/Overlap	Tendinitis + bursitis	Variable presentation	2

Table 2: Types of Pes Anserine Bursitis

Acute Pes Anserine Bursitis

Typically presents as a simple fluid collection within the bursa. Acute cases are often associated with recent increase in physical activity, trauma, or repetitive strain. Symptoms develop rapidly and respond well to conservative treatment 1 3.

Chronic Pes Anserine Bursitis

Chronic cases may present as a persistent, sometimes mass-like swelling that can be confused with tumors or other synovial diseases. MRI imaging may reveal heterogeneous signal patterns and, in rare cases, bony changes such as cortical scalloping or intramedullary extension 3 6. Chronicity often results from ongoing irritation or underlying biomechanical issues.

Pigmented Villonodular Bursitis

This rare form is a benign but potentially aggressive lesion characterized by synovial proliferation and pigmentation (pigmented villonodular synovitis, or PVNS). It can mimic other soft tissue tumors and is confirmed by histological examination. It is extremely rare in the pes anserine bursa but important to recognize due to its unique management requirements 4 5.

Anserine Syndrome / Overlap with Tendinitis

In some patients, inflammation of the pes anserine bursa occurs alongside tendinitis of the associated tendons (sartorius, gracilis, semitendinosus). This overlap, sometimes referred to as “anserine syndrome,” complicates the clinical picture and can make diagnosis less straightforward 2.

Causes of Pes Anserine Bursitis

Pinpointing the underlying causes of pes anserine bursitis is crucial for both prevention and targeted treatment. The condition can arise from a combination of mechanical, anatomical, and systemic factors.

Cause	Risk Group	Mechanism	Source
Overuse	Athletes, active	Repetitive friction	2 10
Obesity	Overweight adults	Increased load	2 8
Osteoarthritis	Elderly, OA patients	Joint alignment/stress	2 8 9
Diabetes	Diabetics	Metabolic changes	2
Trauma	All ages	Direct impact	10
Tumors/Osteochondroma	Children, rare	Local irritation	7

Table 3: Key Causes and Risk Factors

Mechanical Overuse and Repetitive Friction

Repeated movements, particularly those involving knee flexion and extension, can lead to irritation of the bursa. This is common in runners, athletes, or individuals whose activities involve a lot of kneeling or stair climbing 2 10.

Obesity

Excess body weight increases pressure on the knee's inner structures, making overweight individuals more susceptible to pes anserine bursitis. Obesity is a well-established risk factor and is particularly common among adult women with the condition 2 8.

Osteoarthritis

Individuals with osteoarthritis (OA) of the knee have an altered joint structure and gait, which increases stress on the pes anserine region. Studies demonstrate a significant overlap between OA and pes anserine bursitis, with the latter contributing to increased pain and disability in OA patients 2 8 9.

Diabetes Mellitus

Diabetes is associated with a higher risk of developing pes anserine bursitis, possibly due to metabolic changes affecting soft tissues and healing capacity 2.

Trauma and Direct Injury

A direct blow to the inner knee or a fall can acutely inflame the bursa, leading to bursitis. This can occur in any age group but is a less common cause compared to chronic overuse 10.

Tumors and Anatomical Variations

Rarely, anatomical abnormalities such as osteochondromas (benign bone tumors) can cause mechanical irritation and lead to pes anserine bursitis, especially in pediatric populations. Surgical resection may be required in these cases 7.

Treatment of Pes Anserine Bursitis

Effective treatment of pes anserine bursitis is tailored to the underlying cause, severity, and chronicity of symptoms. Both conservative and interventional options are available, with new therapies continually being explored.

Treatment Type	Example	Efficacy/Notes	Source
NSAIDs	Diclofenac, Naproxen	Pain, swelling relief	8 10
Physical Therapy	Exercises, modalities	Improves function	9 10
Injections	Corticosteroid, PDRN	Fast, effective	9 12
Kinesiotaping	Lifting technique	Reduces pain/swelling	10
Mesotherapy	Subcutaneous NSAIDs	Local effect, fewer side effects	8 11
Surgery	Tumor resection	For anatomical causes	7

Table 4: Common Treatments

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

NSAIDs such as diclofenac and naproxen remain first-line treatments, helping to control pain and reduce inflammation. These can be administered orally or, in some cases, via mesotherapy (local subcutaneous injection), which may provide more targeted effects with fewer systemic side effects 8 10 11.

Physical Therapy

A structured physical therapy program can address muscle imbalances, improve flexibility, and strengthen the knee. Modalities such as ultrasound therapy, stretching, and strengthening exercises are commonly employed, with significant improvements in pain and function 9 10.

Corticosteroid Injections

Direct injection of corticosteroids into the pes anserine bursa can offer rapid pain relief, particularly in cases unresponsive to other treatments. These injections are safe when performed under sterile conditions and can be repeated if necessary 9.

Kinesiotaping

Recent studies suggest kinesiotaping is more effective than NSAIDs and physical therapy in reducing pain and swelling. This non-invasive technique, applied by trained professionals, has minimal side effects and can be especially helpful for those seeking drug-free options 10.

Mesotherapy

Mesotherapy involves subcutaneous injection of small doses of NSAIDs directly at the site of inflammation. This technique has shown promise in reducing pain and improving function in patients with pes anserine bursitis associated with knee osteoarthritis 8 11.

Polydeoxyribonucleotide (PDRN) Injection

A newer intervention, PDRN injection, has been reported to provide long-term improvement in pain and function in select cases, although more research is needed to confirm its widespread efficacy 12.

Surgical Management

Surgery is rarely required but may be indicated in cases where anatomical abnormalities (such as osteochondromas) are the underlying cause, or when there is suspicion of mass-like lesions such as pigmented villonodular bursitis 7 4 5.

Conclusion

Pes anserine bursitis is a frequent but often under-recognized cause of knee pain, especially in adults with specific risk factors. Accurate diagnosis is essential to avoid unnecessary procedures and enable early, effective treatment. With a broad range of therapeutic options, most patients can achieve significant relief and return to normal activities.

Main Points Covered:

• Pes anserine bursitis presents with medial knee pain, tenderness, and sometimes swelling or a palpable mass.
• Types range from acute simple inflammation to chronic mass-like forms and rare tumorous variants.
• Causes include overuse, obesity, osteoarthritis, diabetes, trauma, and rare anatomical factors.
• Treatment options include NSAIDs, physical therapy, corticosteroid injections, kinesiotaping, mesotherapy, and rarely surgery.
• Early recognition and tailored therapy are key for optimal recovery and improved quality of life.