A recent patient is a great example of how good the body is at compensating for biomechanical imbalances. He is a young NFL receiver with a one year history of left knee pain. There was no history of trauma to the knee and he described soreness and pain over the front of the knee surrounding the kneecap. He reported pain with squatting, lunging, running, and descending stairs. His training during the football season, and offseason, had to be cut back significantly.
Examination revealed no damage to the knee ligaments or cartilage, and no swelling. He was obviously very muscular and had excellent general fitness. A previous MRI also confirmed no significant structural damage in the knee. Orthopedically, all the tests to his knee were essentially “normal” and we could not elicit his pain with any hands-on tests. So where do you look for the root cause of his pain if the knee exam is normal?
The key to biomechanical testing is to look above and below the injured body part, and even to the opposite side for the underlying causes and imbalances. As the old song goes, “…the leg bone is connected to the…thigh bone….the thigh bone’s connected the hip bone….” For humans to move efficiently (crawl, walk, run), ideally there is symmetry in joint range of motion, alignment and muscle activity.
Looking below this athlete’s knees there were no obvious asymmetries in the lower leg muscles, or foot/ankle joints. However looking above the knees, at the hips and pelvis, there were some remarkable differences between the two sides. The right and left pelvic bones were not aligned with each other, and this caused one leg to appear longer than the other. It also caused his hips to show very asymmetrical range of motion. In fact, the inward rotation of his right hip measured 35 degrees while the rotation on the injured left hip was just 25 degrees.
This asymmetry in hip rotation was a significant problem. Hips are wonderful joints in that they are built for rotation, but knees are not. Knees are essentially “hinge joints”, designed for bending and straightening but not for rotation.
When joints lose motion, the body has to compensate and “find” that mobility from another area. In this athlete the rotational demands that his left hip could not provide were passed down to his knee. This was confirmed when we asked him to rise from sitting up to standing on just one leg. On the right his knee appeared stable and getting up was easy. On the injured left, not only did he struggle to rise up (weaker not painful), his knee dove inward as a compensation for his mis-aligned pelvis, lack of hip rotation, and weakness.
Further assessment included muscle testing measuring strength, and more specifically whether he was able to “activate” key muscles that stabilize the knee without compensation. You would think as a professional football player that his strength would be off the charts. Not so. Numerous left core and hip muscles were “inhibited” and difficult for him to isolate, yet the right side was normal. Initially this was very difficult for him to comprehend since he was regularly in the weight room for core and leg strengthening.
The key for him to understanding this muscular compensation pattern was realizing that while he can leg press 500 lbs. or more, that doesn’t tell me what muscles he is using. In his case, a lack of core and hip muscle control likely increased the demand on his quad/thigh muscles which put even more torque on the front of his knee.
The treatment plan for this patient included three key strategies.
- Correct his pelvic alignment so that he was ‘neutral.’ This would also restore symmetrical hip range of motion.
- Train the weak or inhibited muscles to activate without compensation.
- Functionally strengthen all muscles that work to stabilize the left leg.
By the 3rd visit he had completely corrected the pelvic mal-alignment and could isolate previously inhibited muscles. At the 4th visit he reported that 80 to 85% of his knee pain was gone. At that point he was a true believer in the idea that while his pain may have manifested itself in the knee, the true problem or root cause was elsewhere. I’m fairly confident with a few more exercise progressions that the pain will be 100% abolished.
This post was written by Brad Ott, Owner, Cert MDT, MSPT