A patient with grossly contaminated wound presents 12 hours after an accident. His wound should be managed by -
Any wound can be closed by
primary suture or
delayed primary suture or
left open to heal by secondary closure

Primary suture is suitable for

clean wounds &
selected contaminated wounds after thorough wound toileting & debridement

Delayed primary closure is done for

heavily contaminated wounds
wounds in which wound toileting has been delayed for 6-8 hrs.
But these were the indications earlier. Now the recent approach is:
if the blood supply to the wound is adequate and bacterial invasion is absent, wounds can be safely closed anytime following proper debridement & irrigation. 
if there is established infection and tissue of doubtful viability has been left in situ, then the wound is left open and re-explored after 48 hrs. If there is no infection, and the doubtful viable tissue is now healthy, the deep tissues can be repaired & the wound closed. If however there is further necrosis & infection the wound is again debrided & left open.
Thorough cleaning and primary repair
Thorough cleaning with debridement of all dead and devitalised tissue without primary closure
Primary closure over a drain
Covering the defect with split skin graft after cleaning