OR / Prep · Orthopedic Surgery · endoscopic
You’re scrubbing into
Arthroscopic washout of septic arthritis
Why are we operating?
Pus in a joint is an emergency for cartilage: the scope washes the knee with litres while the cultures are still growing.
Indication: Septic arthritis of the native knee, on aspiration findings and clinical picture; prosthetic joints follow different rules.
The operation in 4 steps
01Confirming and culturing
The joint is aspirated before antibiotics when possible: cell count, Gram stain, crystals, culture.
Why: The aspirate is the diagnosis and the antibiogram; crystals are sought in the same fluid because gout is the great impersonator, and the treatment differs completely.
02Portals and inspection
Standard arthroscopy portals; the joint is inspected compartment by compartment and synovitis graded.
Why: The scope sees what a needle cannot: loculations, fibrin membranes, cartilage state. Each compartment is visited because pus hides behind the fat pad and in the posterior recesses.
03Lavage and debridement
Six to nine litres of saline through the joint; fibrin and infected synovium debrided with a shaver as needed.
Why: Bacterial enzymes and the host's own response digest cartilage within days, and cartilage does not regrow. Volume dilutes the enzymes; debridement removes the surfaces that harbour organisms.
04Drains, antibiotics, reassessment
The joint may be drained, antibiotics run long guided by cultures, and re-washout booked on response rather than by routine.
Why: One washout is often not enough; a knee that stays hot and effused earns a return trip. The prosthetic joint is named as the different disease it is, with its own biofilm rules.
Anatomy you need
Femur, tibia and patella around the joint space the arthroscope enters through its two portals.
What can go wrong
Watch it done
Conceptual teaching for learners preparing to observe and assist under supervision, not operative instructions. Five minutes from now you should know why this operation exists, what its shape is, and which structures it is designed not to injure.