Septic Bursitis (Olecranon / Prepatellar)

Which Antibiotic, at What Dose

Empirical cover is directed at Staphylococcus aureus while also covering streptococci. Typical adult regimens, to be adjusted to local antimicrobial policy, renal function and the culture result:

Duration is the part that changes outcome. A course of at least 14 days applies whether the patient was treated medically or surgically - shorter courses failed more often in the multicentre data, and duration was the variable that separated success from failure rather than the choice between antibiotics and an operation.

Streptococci account for about a fifth of cases, so a regimen must cover them as well as staphylococci. In the immunocompromised, remember that mycobacterial and fungal bursal infection exist and will not grow on routine culture - ask the laboratory specifically if the picture is indolent and standard cultures are sterile.

Where the Patient Is Treated

Septic bursitis is largely an outpatient problem, which is worth stating because the inflamed elbow or knee looks alarming. In a prospective series of 47 patients with acute olecranon or prepatellar bursal swelling - 22 of them septic - managed by a structured protocol, no patient was admitted initially; only two were admitted later, for two days each, and only one required incision and drainage. Pain scores fell from 4.8 to 1.7 for olecranon and 3.8 to 2.7 for prepatellar septic bursitis by the first review, which was at two to three days - so a definite early review, rather than admission, is what the structured approach depends on.

Reserve admission for genuine systemic sepsis, extensive or rapidly spreading cellulitis, significant immunocompromise or uncontrolled diabetes, an abscess needing drainage, or an unreliable social situation where early review cannot be guaranteed.

Open Versus Endoscopic Bursectomy

When surgery is needed, the wound is the problem, and the reason is anatomical: an open bursectomy is performed through an incision directly over the bursa, where the skin has a tenuous blood supply and is the surface the patient leans or kneels on - hence the well-recognised rate of necrosis and dehiscence.

• Placing an open incision. Avoid a midline longitudinal incision over the kneeling or leaning surface; a transverse or parapatellar approach keeps the scar off the point of contact - the part of the knee that meets the floor, or the part of the elbow that meets the desk.
• Endoscopic bursectomy is the alternative, initially described for aseptic disease and since applied to infection. In a series of 27 recalcitrant septic bursae (14 olecranon, 13 prepatellar) it produced no wound-healing complications and one minor recurrence, with shorter hospital stays - directly addressing the wound problem that makes the open operation unattractive. The concern it was designed to answer was whether endoscopy debrides infected tissue thoroughly enough to prevent recurrence; that series suggests it does.