2 weeks ago today I was playing in a soccer game, I had my foot planted and attempted to move quickly out of the opposing girls way, well since my foot was planted, my body went and my knee/leg stayed.. I heard a loud pop and also felt it. Other people around me heard it as well. I immediately hit the ground, I'm pretty sure I was thrashing around like a fish out of water, it was so painful!!! I couldn't walk on it or bend it. I went to the ER (veterans hospital, not the best healthcare), he performed a lachmans test, but it was about 3-4 hours after injury and I was sitting in a wheel chair, not laying down! He said it was a sprain but to follow up with my PCP.. It began to swell, not a lot like double but it was a little swollen for 4 days. A few days later I was walking on it with a limp.. It still hurts to go up and down stairs or curbs. I tried running on it just to see if it was better, it didn't hurt but there was a weird sensation, hard to explain. Yesterday I was walking, my knee just gave out, I didn't fall but it was noticale to those around me. I don't know if it has to do with the injury of if it was just coincedence.. Maybe I'm in denial.
My question is do you think this is just a sprain? Should I cancel my MRI appt?
Any injury to a ligament is termed a sprain. There are four major ligaments in the knee; the MCL and LCL (the collateral ligaments) and the PCL and ACL (the cruciate ligaments).
The collateral ligaments, on either side of the knee, are on the outside of the joint, and as such, will usually heal on their own. These ligaments are usually injured in contact injuries. Where the foot is planted and the athlete is hit on the side of the knee. The knee then buckles sideways. Often the athlete will hear or feel a clunk or snap. The swelling from these injuries is outside of the joint, located directly over the injured ligament.
The cruciate ligaments are inside of the joint capsule. They are bathed in synovial fluid, and as such, will not heal on their own. The ACL is usually injured in noncontact twisting injuries. A wide receiver goes up for a pass, comes down, and falls to the ground in pain. Or a basketball play goes up to a lay up with no one around, comes down, and falls to the ground. Sometimes the athlete will hear or feel a pop. The swelling associated with an ACL injury is called an effusion, as it is inside the joint. As such, the swelling is generalized and if massive can be seen as a horseshoe at the proximal end of the patella (kneecap).
Lachman's can be done with the patient in any position (even lying prone) but the knee should be at a 30 degree flexion. It should really be done at 30 and 90, to get a good assessment, as should the varus and valgus stress testing.
To do a thorough exam, the patient should be lying down, relaxed. But, if you are just triaging and are not going to be treating the injury, as soon as you know what your next diagnostic step is going to be, there is no need torturing the patient any more. So, once the decision that an MRI was necessary, that's about as far as the exam needed to go at that time.
However, the surgeon who is going to be doing the definitive treatment will need to do a very thorough examination. Many times, the full exam is delayed a few days, till the patient is more comfortable and can relax for the exam. An extensively guarding patient makes the exam impossible.
So, by the time you get the MRI, you should be able to have a full exam of the knee. And the exam is actually the most important diagnostic test. The MRI will help to know if there are any bone bruises or meniscal injuries. But, as to the instability, the exam in the gold standard. But, the physician has to have been trained to do a thorough knee exam, which is the realm of the orthopedic surgeon. Most physicians can to a cursory exam of the knee, but that is all. Just like, you do not want an orthopedic surgeon looking at your EKG, that's the cardiologist's realm.
As to the giving way yesterday, that could be from the ligament instability, but after an injury, it is usually from the quads giving out. The quad strength goes down very quickly after an injury. And, the quads are the main postural muscles in the lower limbs, they keep your knees from buckling. Pain can also cause the knee to buckle or give way.
While you are waiting for the MRI and orthopedic evaluation, be sure to maintain the knee range of motion, especially extension. Do not sleep with the knee draped over a pillow, as that allows the posterior capsule to contract. And it is very hard to regain extension if you lose it. It is also very hard to walk with a bent knee, you end up walking on your toes. So, work on keeping your motion going and be sure to get the knee straight.
You can also work on your quad strength, as the pain allows. You may want to ice before and after your exercises.
Good luck. Hope that you do not have an ACL injury, that would not be great. But, if you have an MRI scheduled, you should probably have it done. Again, good luck.