M71.06 Abscess of bursa, knee

Name of the Condition

• Abscess of bursa, knee

Summary

An abscess of the bursa, knee is a localized collection of pus within the bursa of the knee, a small fluid-filled sac that reduces friction between tissues. This condition typically causes pain, swelling, and warmth at the affected site. The knee-specific designation indicates the abscess is localized to the bursa in the knee region.

Causes

Abscesses of the knee bursa usually result from bacterial infection, often introduced through direct trauma, skin breakdown, or spread from adjacent tissues. Staphylococcus aureus is a common causative organism. Non-infectious causes, such as foreign body reaction or sterile inflammation, are less frequent.

Risk Factors

• Recent injury or surgery near the knee bursa
• Skin infections or open wounds in the knee area
• Immunocompromised states (e.g., diabetes, HIV)
• Chronic inflammatory conditions (e.g., rheumatoid arthritis)
• Repetitive motion or pressure on the knee bursa

Symptoms

• Localized pain, tenderness, or throbbing in the knee
• Swelling, redness, or warmth over the bursa
• Limited range of motion in the knee joint
• Possible fever or systemic signs if infection spreads
• Pus drainage if the abscess ruptures

Diagnosis

Diagnosis involves a physical examination to assess bursal swelling, warmth, and tenderness. Imaging (e.g., ultrasound) may confirm fluid collection. Aspiration of the bursa may be performed to identify the causative organism and guide treatment.

Treatment Options

Treatment typically includes antibiotics to address infection and drainage of the abscess if necessary. Rest, elevation, and anti-inflammatory medications may help reduce symptoms. Severe cases may require surgical intervention to remove the abscess.

Prognosis and Follow-Up

With appropriate treatment, most cases resolve without long-term complications. Follow-up care ensures infection clearance and monitors for recurrence. Physical therapy may be recommended to restore joint function.

Complications

Untreated abscesses can lead to spread of infection, joint damage, or systemic sepsis. Chronic inflammation may result in persistent pain or limited mobility.

Lifestyle & Prevention

Avoiding trauma to the knee, maintaining skin integrity, and managing underlying conditions (e.g., diabetes) can reduce risk. Proper wound care and prompt treatment of infections are important preventive measures.

When to Seek Professional Help

Seek care if symptoms worsen, fever develops, or pus drainage occurs. Persistent pain, swelling, or limited mobility should also prompt evaluation.

Tips for Medical Coders

Document the specific bursa involved (knee) and any associated infection or trauma. Ensure clinical notes support the diagnosis and treatment provided. Code M71.06 is specific to the knee bursa and should not be used for other sites.