There's been a lot of debate over what really is wrong with Garnett. Hopefully this helps clear some of the confusion up (Globe):
Kevin Garnett will miss the NBA playoffs and likely have surgery on his right knee during the offseason, Celtics coach Doc Rivers said today.
The surgery will be to remove a spur in Garnett's knee. But a strained popliteus tendon -- and not the spur -- has affected Garnett's inability to return from a Feb. 19 injury. The tendon strain must heal naturally, and has taken longer than anticipated.
Wyc seems to be optimistic of the long term:
Celtics owner Wyc Grousbeck said he's confident Garnett is going to be "absolutely fine, 100 percent, over the long term. The short term is much less clear at this point."