Should you drain prepatellar bursitis?

Management of Prepatellar Bursitis: Drainage Recommendations

Drainage of prepatellar bursitis should be performed for septic cases, while non-septic cases should generally be managed conservatively without drainage.

Differentiating Septic vs. Non-Septic Bursitis

Initial differentiation between septic and non-septic prepatellar bursitis is crucial for determining appropriate management:

Clinical Indicators of Septic Bursitis:

• Fever >37.8°C, prebursal temperature difference >2.2°C, and visible skin lesions 1
• Rapid onset of symptoms with significant pain, erythema, and warmth 2
• History of trauma with skin break preceding infection 3
• Occupational exposure (kneeling occupations increase risk) 3, 2

Diagnostic Aspiration Findings Suggesting Septic Bursitis:

• Purulent aspirate appearance 1
• Fluid-to-serum glucose ratio <50% 1
• White cell count >3,000 cells/μl in aspirate 1
• Polymorphonuclear cells >50% in aspirate 1
• Positive Gram staining and/or positive culture 1, 2

Management Algorithm

For Non-Septic Prepatellar Bursitis:

• Conservative management with PRICE (Protection, Rest, Ice, Compression, Elevation) 1
• NSAIDs for pain and inflammation 1
• Aspiration may be performed for symptomatic relief of large effusions, but without drainage catheter placement 1
• For recalcitrant cases, consider intrabursal steroid injection (for patients with high athletic or occupational demands) 1
• For chronic recurrent cases, sclerotherapy may be considered as an alternative to surgery 4

For Septic Prepatellar Bursitis:

• Aspiration with appropriate cultures to guide antibiotic therapy 1, 2
• Initiate empiric antibiotic therapy targeting Staphylococcus aureus (most common pathogen in 76-88% of cases) 2
• For mild cases: oral antibiotics with close follow-up 3
• For moderate to severe cases: intravenous antibiotics with splinting 3
• Drainage is indicated for septic bursitis that is severe or unresponsive to initial aspiration and antibiotics 5

Drainage Options for Septic Bursitis:

• Percutaneous catheter drainage with suction-irrigation system for continuous drainage 6
• Surgical incision and drainage for severe cases with extensive infection or abscess formation 3
• Complete bursectomy should be reserved for chronic/recurrent cases or those failing other interventions 1

Important Considerations

• Oral antibiotics alone are often inadequate for treating septic bursitis 3
• Septic bursitis must be distinguished from septic arthritis (which involves the joint space rather than the bursa) 2
• Staphylococcus aureus is the most common causative organism, with many strains resistant to penicillin 2
• Percutaneous drainage with suction-irrigation systems has shown excellent results with no complications or recurrences in small studies 6
• Patients with preexisting chronic bursitis or occupational kneeling may continue to have symptoms even after successful treatment of infection 3

Pitfalls to Avoid

• Misdiagnosing septic bursitis as non-septic bursitis despite characteristic bursal fluid leukocytosis and positive cultures 2
• Delaying drainage in severe septic cases, which can lead to extensive tissue damage 5
• Immediate surgical bursectomy for all septic cases is not supported by evidence; a more conservative approach should be pursued initially 1
• Failing to address underlying risk factors (occupation, protective equipment) may lead to recurrence 3, 2

Remember that cellulitis surrounding a suppurative focus like an infected bursa should be termed "septic bursitis with surrounding inflammation" rather than "cellulitis," as this distinction guides proper treatment (drainage for the collection plus antibiotics) 5.