M71.16 Other infective bursitis, knee

Name of the Condition

• Other infective bursitis, knee

Summary

Other infective bursitis, knee refers to an infection of the bursa in the knee region that is not classified under more specific infective bursitis codes. This condition involves microbial invasion of the bursa, leading to inflammation, pain, and potential functional impairment of the knee joint.

Causes

Other infective bursitis, knee typically results from bacterial infection, often introduced through direct trauma, skin breakdown, or spread from adjacent tissues. Common causative organisms include Staphylococcus aureus. Non-bacterial infections or secondary infection of a pre-existing bursitis may also occur, though the exact etiology varies by case.

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, swelling, and warmth over the knee bursa
• Redness or erythema at the site
• Fever or systemic signs of infection
• Limited range of motion in the knee joint
• Pus drainage if the infection progresses

Diagnosis

Diagnosis involves a physical examination to assess bursal characteristics, including tenderness, warmth, and swelling. Imaging studies (e.g., ultrasound or MRI) may be used to evaluate the bursa and surrounding tissues. Aspiration of the bursa for fluid analysis (e.g., culture, cell count) helps confirm infection and identify causative organisms.

Treatment Options

Treatment typically includes antibiotic therapy targeted at the identified or suspected pathogen. For localized infections, oral antibiotics may suffice, while severe or systemic cases may require intravenous antibiotics. Aspiration or surgical drainage of the bursa may be necessary for abscess formation or persistent fluid accumulation. Rest, elevation, and anti-inflammatory measures can help reduce symptoms.

Prognosis and Follow-Up

With appropriate treatment, most cases of infective bursitis resolve without long-term complications. Follow-up care ensures infection resolution and monitors for recurrence. Patients with underlying risk factors (e.g., immunocompromise) may require extended antibiotic courses or closer monitoring.

Complications

Untreated or severe infections can lead to abscess formation, spread to adjacent tissues, or sepsis. Chronic bursitis or persistent pain may occur if the infection is not fully resolved. Rarely, joint involvement or functional impairment of the knee may result.

Lifestyle & Prevention

• Avoid trauma or excessive pressure on the knee bursa.
• Promptly treat skin infections or wounds near the knee.
• Maintain good hygiene and wound care.
• Manage underlying conditions (e.g., diabetes) to reduce infection risk.
• Use protective gear during activities that stress the knee.

When to Seek Professional Help

Seek medical attention if symptoms worsen (e.g., increased pain, swelling, fever) or if pus drainage occurs. Immediate care is needed for signs of systemic infection (e.g., chills, confusion) or if the knee becomes increasingly immobile.

Tips for Medical Coders

Document the specific site (knee) and confirm infective etiology to justify M71.16. Ensure clinical notes specify the bursa involved and evidence of infection (e.g., culture results, aspiration findings). Differentiate from non-infective bursitis or other knee conditions to avoid miscoding.