Question

1) should you perform a below knee amputation (BKA) immediately? (2) Should you perform a surgical debridement followed by antibiotic treatment to save the ankle? Although the second option offers a chance of complete recovery, it is associated with a substantial risk of infection that spreads, possibly leading to an above the knee amputation (AKA) or a BKA, or even death. Even if this second option is successful, there is still a chance of minor long term disability of the limb

create a decision tree:

Outcomes	Probability
Foot saved using antibiotics	0.55
Full recovery after foot saved	0.80
Recovery with a limp after foot saved	0.20
Death after infection is not controlled by antibiotics	0.10
AKA after infection not controlled by antibiotics	0.75
BKA after infection not controlled by antibiotics	0.15
Survival after immediate BKA	1.00

Possible Outcome	Utility
Recovery with a limp	0.98
Recovery with BKA	0.70
Recovery with AKA	0.60
Entire limb saved and no limp	1.00
Death	0.00

Answer 1