Understanding Tendinopathy
The patella tendon is a large tendon connecting the kneecap to the lower leg. It is a continuation of the quadriceps tendon which connects to the upper part of the knee cap and the quadriceps muscles in the front of the knee. Injury to the tendon can be problematic for athletes in a variety of sports. Due to significant stresses with sprinting sports as well as with lower body exercises such as squats, the patella tendon is susceptible to overuse injuries such as tendonitis or tendinopathy. Over time, typically within 1 to 3 months, if the tendonitis persists, the tissue can undergo degenerative changes that cause the tendon to develop a more chronic pain. The underlying changes to the tendon do not usually have definitive inflammation, and so the name changes to tendinopathy, rather than tendonitis.
Evaluation of Patella Tendon
Athletes will usually have no notable swelling over the front of the knee, rather pain directly over the tendon. If there is swelling, it is usually concentrated over the tendon rather than throughout the entire knee such as in an ACL tear or Meniscus tear. Tenderness is typically seen with deep pressure directly over the patella tendon (pictured below). Pain may also be reported at the patella tendon with extension of the knee against resistance, as well as with exercises like lunges or squats. In my experience, the pain is typically most severe at the proximal portion just below the knee cap.
Imaging of Tendinosis
Tendinosis can usually be easily imaged using MSK ultrasound detecting a thickened and heterogeneous tendon compared to the normal width and uniform normal appearance. In the photos below, the large black (hyperechoic) region within the affected tendon is consistent with patella tendinosis.
If tendinosis is identified under ultrasound visualization, the doppler setting can be used to visualize neovascularization within the tendon as indicated in the image below.
Treatment and Return to Play
My recommendation on a plan of action for patella tendinopathy really depends on the individual situation. If it is relatively early on and the patient hasn’t tried much in the way of therapy, I usually will give them a trial of physical therapy for 4 to 6 weeks utilizing eccentric exercises and dry needling. If they fail a trial of physical therapy or have had symptoms for years I will recommend an ultrasound-guided needle tenotomy. Essentially, under ultrasound guidance, we will take an 18 G needle and pass it through the area of tendinosis to stimulate an inflammatory reaction within the tendon to hopefully improve pain. The tenotomy procedure can be augmented with injecting PRP or hypertonic saline to try to improve the response. I am aware of other techniques where providers will use normal saline to dissect away the underlying Hoffa's fat pad which is thought to contribute to the condition.