Knee Pain and your VMO
There are many different factors which may influence the onset of knee pain. Overuse injuries, trauma, post surgical and muscular imbalances to name a few. One general theme that seems to hold true in rehabbing knee pain despite the above etiologies I mentioned is the isolation of the medial compartment. This is often referred to as the VMO (Vastus Medialis Oblique). This muscle is one of the four quadriceps which rests closer to the midline of the body. It plays a crucial role in the distribution of forces on the patella. Quite often we find knee pain associated with an inflammatory response with the structures involved in that area (whether this be inert structures like cartilage/ligament and bursa or contractile tissue such as muscle and tendon.). With only a trace of inflammation, the VMO can literally be shut down or non-effective in its function. Post surgically, e.g., Meniscus or ligament, the VMO is the first muscle of the quadriceps to atrophy and the last one to regain full functional strength. The VMO functions to initiate the contraction of the quadriceps. Its timing sequence is crucial. Any inflammation in this region of the knee can delay its firing sequence causing it lag behind. When this happens, the patella can deviate laterally or away from the midline of the body. In extreme cases, this can lead to subluxation of the patella or even dislocated patella. More common post surgical secondary issues seen with knee rehab is irritation from improper tracking of the patella over the femoral condyle’s. PT recommendation: Isolated strengthening for the medial quadriceps (VMO) of the knee and stretching of the lateral compartments (distal IT band, vastus lateralis and lateral retinaculum). Isolated strengthening can be done by performing quadriceps sets, straight leg raises, theraband in sitting ( 0°-> 30°). Stretching the lateral structures can be done in standing, e.g., for the right knee, cross the left foot over the right with both knees fully extended, then slowly slide your hands down towards the left side of the right foot until a gentle stretch is felt and hold for 30 seconds. These are but a few basic exercises to help relieve pain in the knee by promoting proper symmetry between strengthening of the VMO and stretching of lateral compartment.
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As always, if you have further questions or specific physical therapy needs regarding treatment, please call me. Oregon Physical Therapy & Sports Medicine Center (971) 238-3343.