Knee pain and injuries are very rarely life threatening, but severe pain and injuries of knee might cause disabling. Some knee injuries might lead to irreversible and chronic complications to the health such as long lasting knee dysfunction. Some knee injuries, including knee joint or kneecap dislocations can result in blood vessel injuries and severe disability. Moreover, some knee pain, especially in the case of osteoarthritis is likely to stay permanently and the reason is that the structure of the knee suffers immense damage. Without seeking a proper treatment or any extensive surgery the sufferer will continue to feel swollen, inability to move, and significant pain.
The long term presence of knee pain symptoms leads to irritation in the knees, flair ups of pain, and reduced range of motion. Luckily, knee pain subsides on its own in the case of acute knee pain without ever looking for a specific cause. The condition of knee pain can advance and might light to more severe injuries or complications depending on the underlying cause of pain. Some commonly occurring complications include infections, fractures, neurological and vascular complications, persistent laxity issues, loss of motion, and gait changes. Following is the description of some complications that might arise due to persistent knee pain:
Soft tissue injury
There is an occurrence of significant soft tissue injuries after the initiation of chronic knee pain which is an indicator of serious complication. It is important to address these soft tissue injuries first before taking any medication or going for a surgical treatment. The injuries in the soft tissues surrounding the knee joint and its associated structures increase the risk of causing an infection in the knee joint. Although it is very rare, but the soft tissue injuries causing an infection might lead to amputation from above knee leg in severe cases. The doctors first ensure the healing of any soft tissue injury and then treat the underlying knee problem. 
1Multiple Ligament Knee Injuries (MLKI)
Multiple ligament knee injuries usually arise after the incidence of knee or kneecap dislocations either due to a low velocity sport injury or a high energy accident of motor vehicle. There is potential morbidity resulting after knee dislocation along with neurovascular damage. The chronic knee pain persistence after a knee dislocation leads to disruption of multiple ligaments surrounding the knee thus making the patient more disable. The complication rates are particularly higher in the case of knee dislocation patients and require extensive operative treatments.