A patient with grossly contaminated wound presents 12 hours after an accident. His wound should be managed by -
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
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.