Traumatic knee dislocations are fairly rare so we don’t have a lot of data from high-quality studies to base treatment recommendations on. The surgeon assesses the damage; takes into consideration the patient’s age, general health, and activity level; and formulates the best plan of action possible.
Most of the time, knee injuries severe enough to cause the joint to dislocate also cause significant soft tissue damage. Multiple ligaments are torn or ruptured requiring surgery. There can also be damage to the nerves and blood vessels in the knee creating even more complications.
Although there’s no way to predict for sure the final result being a joint replacement, there are ways to work against that outcome. A rehab program aimed at increasing joint stability through muscle strengthening is advised. The physical therapist will check for any postural problems that might add uneven load or force to the joint and help you achieve better alignment if possible. Specific training will be needed to restore joint proprioception (joint sense of position) and kinesthesia (awareness of movement).
Rehab to prevent joint replacement is the type of approach that requires some discipline and dedication on your part. You won’t be able to follow the exercise program for six weeks and call it quits. This type of prevention requires ongoing perserverance. But it can pay off in the end as many patients (especially athletes) can report.