What is a dislocation ?
Dislocation of a joint means that the two surfaces are no longer in contact with each other (See diagram). This can happen at any joint in the finger or thumb. The most common joint to be dislocated is the middle joint in the finger the proximal interphalangeal joint (PIPJ). The direction of dislocation will depend on the forces applied at the time of the injury. Some dislocations will be associated with a fracture (break) in the bones involved, this may make the treatment more difficult and the outcome more uncertain. The dislocation may damage the ligaments that support the sides and front of the joint with the risk of long term instability.
How does it happen ?
Most dislocations occur as the result of a fall or a sporting accident. Less commonly dislocations can occur as the result of being involved in a violent incident or in a road accident. Dislocations occur because the joint is pushed into an abnormal position and the ligaments, that support the joint and hold the bones in the correct place, give way. This allows the bones to slip out of position.
What is the treatment ?
The treatment is to reduce the joint back into its normal position. This can be a simple task which is performed under local anaesthetic or if the injury is more complicated require a surgical operation under anaesthetic. The majority of dislocations are simple and can be manipulated back into the correct position easily. This is usually done in the accident and emergency department.
Following the initial treatment you may need to wear a splint for a few weeks and to attend therapy to help move the joint while protecting it from further damage. The precise nature of the rehabilitation programme will depend on the type of injury sustained. Your surgeon and therapist will discuss the exact programme with you.
What is the outcome ?
For most simple cases there will be a return to normal function. However a dislocation is a serious injury and in some cases there may be residual stiffness of the joint, which could require further therapy or surgical treatment.
Any dislocation where there is a fracture involving the surface of the joint is likely to have some long term stiffness and is also at risk of developing arthritis in the joint. The arthritis usually takes many years to develop but can occur rapidly on occasion.
Should the ligaments not heal satisfactorily there is a risk that the joint will become unstable and prone to further dislocations. An unstable joint may also cause loss of function in the finger. If this happens further surgery may be needed.