In a car accident, your entire body is moved forcefully, often coming into contact with the hard or protective surfaces in your vehicle. For someone in the front seat, this can mean hitting your head or knee against the dashboard. This is common enough that “dashboard knee” is a term for certain injuries that many car accident chiropractors use. Because this kind of injury can be extremely painful and lead to knee problems if untreated, it’s important to understand the impact and treatment of dashboard knee.
Types of Knee Injuries from Dashboards
There are two main types of injuries that knees sustain when they collide with a dashboard. The less common of the two is a fracture of the patella, which is the kneecap. When this occurs, the bone can be split in two or can shatter into many tiny fragments on impact. In both cases, you may experience difficulty or inability to walk and bear weight on the leg soon after the incident.
The more common injury is a tear to the posterior cruciate ligament (PCL). This ligament is located in the back of the knee and connects the thighbone and the shinbone, also keeping the shinbone in place and preventing it from being pushed back too far. It crosses with an anterior ligament (the ACL), which together create the stability your knee needs to move back and forth and sideways.
When the knee hits the dashboard, it can push the shinbone backward, stretching it beyond its capability and tearing the PCL. This can also happen during sports injuries or slip and falls, usually in conjunction with other injuries to the knee. It can be difficult to diagnose a PCL injury, though symptoms may include pain, swelling, and trouble walking.
Diagnosing Dashboard Knee Injuries
Both fractures and PCL tears can be found on imaging. An x-ray would show a fracture but not ligament damage, so if bone problems are ruled out, you may be sent for an MRI. A swollen knee can be difficult for doctors to examine, so they may rely on certain tests in addition to imaging. One such test is the “posterior drawer test,” where the doctor pushes your shin back with the knee bent at 90 degrees. If the tibia gives more than 5 millimeters, a PCL tear is likely. Imaging can further help doctors to understand the extent of your tear.
Treating Dashboard Knee Injuries
The type and invasiveness of your treatment will depend on both the type of injury you have sustained and how severe it is.
For a fractured patella, a splint or cast will usually be placed to keep your knee in place and allow it to heal. However, if the fractured pieces of the patella aren’t properly placed, these measures may not work, and surgery may be necessary.
PCL tears can sometimes be treated with rest and a regiment of physical therapy designed to strengthen the muscles and improve knee function. This conservative method is usually preferred, but surgery could be necessary in severe cases. The right treatment can depend on the stage or grade of your PCL tear. The injury can be broken down into three stages:
- Stage 1: a partial tear of the PCL
- Stage 2: a complete tear of only the PC
- Stage 3: a complete tear of the PCL as well as injuries to other parts of the knee.
Stage 1 injuries almost ever require surgery, while Stage 2 injuries can be treated conservatively in some cases to avoid surgery. Stage 3 almost always requires more invasive procedures.
One of the most important things you can do to prevent any injury during a car accident is to properly use your seatbelt. In most cases, these will restrain you enough that your knee cannot reach the dashboard, avoiding fractures and PCL tears. But it is still possible to slip beneath the seatbelt and have this happen. A history of knee injuries can put you at higher risk as well.
If you do suffer a knee injury during a car accident, seeking treatment quickly will be critical to ensure you are able to use the knee fully in the future. At AICA College Park, our doctors will be able to diagnose your injury and create a customized treatment plan designed around your goals. With access to imaging, physical therapy, chiropractic care, and even surgery onsite, AICA College Park offers comprehensive solutions to the injuries you sustain during car accidents.