This is a hyperextension injury, which is essentially a ligamentous injury, although it may involve a portion of bone avulsed off by a ligament. It usually involves a piece of bone avulsed off the base of the middle phalanx by the volar plate, which is usually not significantly displaced and usually will heal without problem. It also usually involves a collateral ligament tear, which heals without problem but often heals with abundant scar tissue, leading to an appearance of chronic swelling on one side of the joint, which is permanent.
No more than a few days of immobilization is necessary, and it is important to work on obtaining full range of motion of the joint. The middle joint of the fingers is the worst with regards to stiffness and early range of motion is very important. Range of motion exercises may be explained to the patient or therapy with a hand therapist may be necessary.
"Buddy taping" of the fingers after the initial few days of immobilization is all that is necessary for finger support. At first, "buddy taping" will be necessary all the time, gradually progressing to "buddy taping" only with exertive or sporting activities with effected hand.
If motion is begun early, full range of motion can be expected. For those who have been immobilized longer, permanent stiffness may result. Rarely, with severe stiffness, surgical release of the scarred tendons and joint capsule may be necessary. Also rarely, instability may result, which may require reconstructive surgery. Most patients do extremely well, being able to progress to painless activity with full function, with minimal abnormal appearance.