Ryandeo30,
You do not say how the fracture was treated, but in today's medical world, it is usually with an IM nail.
It usually take around 16 to 20 weeks for a femur fracture to unite. Some patients heal a little faster, some slower. But, this is just the time for the bone to heal.
This does not include the time for soft tissue rehabilitation. That can take up to 12 to 18 months.
You have to remember that you broke the largest bone in the body. It takes a lot of energy to do that. Not only the bone is injured. The periosteum is ripped off the bone, the muscles attachments are torn off, and the tendons, ligaments, fascia, nerves, blood vessels all get stretched and twisted while the thigh is not supported by an intact bone.
All of that soft tissue damage has to heal. Soft tissue heals with scar tissue. Scar tissue does not stretch or contract like regular tissues. It takes a while for the scar to mature, then it has to be rehabilitated.
At four months, you are just barely into the rehab phase. But, you are 90% back, that is really pretty good.
However, if you are having a lot of problems in the knee, you should have your orthopedic surgeon exam the knee. Occasionally, the knee is also injured in a femur fracture, but since the fracture is most important to treat right away, sometimes the knee injury gets overlooked till the patient start doing rehab.
Hang in there. You still have quite a ways to go. Have your surgeon take a look at your knee, the next time you see him/her.
Good luck.